an investigation into the development of environmentally

An Investigation into the

Development of Environmentally

Friendly Pigment Colouration

A thesis submitted to the University of Manchester for the degree of

Doctor of Philosophy (PhD)

in the Faculty of Engineering and Physical Sciences

2013

Qingqing Cao

School of Materials

Contents

1

Contents

Contents 1

List of Figures 6

List of Tables 13

Glossary of Terms 16

Abstract 17

Declaration 18

Copyright Statement 19

Acknowledgements 20

Chapter 1 Textile Colouration 21

1.1 Definition 21

1.2 History 21

1.3 Classification 23

1.3.1 Textile printing 23

1.3.2 Textile dyeing 24

1.4 Textile colouration of cotton 25

1.4.1 Cotton fibres 25

1.4.2 Colourants for cotton 27

1.5 Textile colouration for polyester 30

1.5.1 Polyester 30

1.5.1.1 Poly (ethylene terephthalate) Fibres 32

1.5.1.2 Poly (lactic acid) Fibres 32

1.5.2 Dyeing polyester 33

1.6 Machinery 34

1.6.1 Dyeing machinery 34

1.6.1.1 Dyeing in the loose fibre form 35

1.6.1.2 Dyeing yarn 35

1.6.1.3 Dyeing fabrics 36

1.6.1.4 Continuous dyeing equipment 39

1.6.2 Printing machinery 40

1.7 References 42

Contents

2

Chapter 2 Pigment Colouration 46

2.1 Definition and overview 46

2.2 History 46

2.3 Pigments 47

2.3.1 Definition 47

2.3.2 History 47

2.3.3 Dyes and pigments 48

2.3.4 Classification of pigments 50

2.3.4.1 Organic pigments 50

2.3.4.2 Water-soluble dyes 54

2.3.4.3 Inorganic pigments 54

2.4 Binder system 55

2.5 Softeners 56

2.6 Other Auxiliaries 58

2.7 Pigment Application System 60

2.7.1 Print System 60

2.7.2 Padding System 60

2.7.3 Exhaust Dyeing System 61

2.7.4 Modification of Pigment Application System 61

2.7.4.1 Cationization 61

2.7.4.2 Plasma Treatment 62

2.7.4.3 Fluorocarbon Treatment of dyed fabrics 64

2.8 Advantages and Disadvantages of Pigment Colouration 66

2.9 Aims and Objectives of Research 67

2.10 References 68

Chapter 3 Instrumental Techniques 73

3.1 Introduction 73

3.2 Physical Testing 73

3.2.1 Colour fastness 73

3.2.1.1 Rub fastness 74

3.2.1.2 Wash fastness 75

3.2.2 Colour Strength 76

3.2.3 Martindale Abrasion Test 77

3.2.4 KES-F System 77

3.2.5 Oil and Water Repellency Measurements 80

3.3 Analytical Methods 82

3.3.1 Scanning Electron Microscopy (SEM) 82

Contents

3

3.3.2 X-ray Photoelectron Spectroscopy (XPS) 83

3.3.3 Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) 84

3.4 References 85

Chapter 4 Investigation of Basic Binder System 87

4.1 Introduction 87

4.2 Experimental 88

4.2.1 Materials 88

4.2.2 Dyeing System 89

4.2.3 Matrix OSD System 89

4.2.4 Modified Matrix OSD System 90

4.2.5 Matrix OSD without Softener 90

4.3 Results and Discussion 91

4.3.1 Matrix OSD System 91

4.3.2 Modified Matrix OSD System 94

4.3.2.1 Treatment on Cotton 94

4.3.2.2 Treatment on PET and Polycotton 106

4.3.3 Effect of Curing Time on the Performance of the Matrix OSD System 107

4.3.4 Performance of Matrix OSD without Softener System 109

4.4 Conclusions 112

4.5 References 113

Chapter 5 Investigation into the Effect of Crosslinkers, Cationisation and

Surface Modification on the Performance of Matrix OSD Treatments 115

5.1 Introduction 115

5.2 Experimental Work 117

5.2.1 Materials 117

5.2.2 Pigment Dyeing System 117

5.2.3 Fabric Pretreatment by Cationic Fixing Agent 117

5.2.4 Crosslinker Treatment 118

5.2.5 UVO treatment 119


5.3.1 Effect of Cationization Treatment 120

5.3.2 Effect of Crosslinkers 122

5.3.2.1 Effect of Nanolink 122

5.3.2.2 Effect of Citric Acid 123

5.3.2.3 Effect of Knittex MLF New 126

5.3.2.4 Effect of Citric Acid and Knittex MLF New 128

5.3.2.5 Effect of DMDHEU Pre-Treatment 131

5.3.3 Effect of UVO Treatment 132

Contents

4

5.4 Conclusions 139

5.5 References 140

Chapter 6 Investigation into the Effect of Flurocarbon Treatments on Matrix

OSD Treated Fabric Performance 141


6.2 Experimental Work 142

6.2.1 Materials 142


6.2.3 Fluorocarbon Treatment 143

6.2.3.1 Scotchguard FC3548 143

6.2.3.2 Shield F-01 with Shield Extender FCD 143

6.2.3.3 Shield FRN6 144

6.2.3.4 P2i 144

6.2.3.5 Oleophobol 7713 with Hydrophobol XAN 144

6.2.3.6 Rucoguard LAD and Oleophobol 7713 145


6.3.1 Effect of Scotchguard FC3548 146

6.3.2 Shield F-01 with Shield extender FCD 154

6.3.2.1 Treatments on Cotton 154

6.3.2.2 Fluorocarbon Treatments on Polycotton Fabric 159

6.3.3 Shield FRN6 161

6.3.4 Effect of P2i dry plasma polymerisation treatments on pigment dyed

fabric fastness and liquid repellency performance 169

6.3.5 Effect of Oleophobol on repellency performance 175

6.3.6 Water/Oil Repellency Performance 178

6.3.6.1 Fluorocarbon Application to Undyed Cotton Fabric 178

6.3.6.2 Matrix OSD System with No Softener 179

6.3.6.3 Rucoguard LAD and Oleophobol 7713 180

6.4 Conclusions 181

6.5 References 182

Chapter 7 Investigation into the Effect of Plasma Treatment on Matrix OSD

Treated Cotton Fabric 183


7.2 Experimental work 184

7.2.1 Materials 184


7.2.3 Plasma Treatment 184

7.2.3.1 Plasma pre-treatment 184

Contents

5

7.2.3.2 Plasma after-treatment 185


7.3.1 Effect of Pre-treatment 185

7.3.2 Effect of Plasma After- treatment on the Fastness of Pigment Dyed

Fabrics 187

7.4 Conclusions 194

7.5 References 195

Chapter 8 Surface Analysis 197

8.1 XPS Analysis of Blue Pigment-dyed Cotton Treated with Fluorocarbons 197

8.2 ToF-SIMS Analysis of Blue Pigment-dyed Cotton Treated with Fluorocarbon

Finishes 211

8.2.1 ECE Detergent with Phosphates 211

8.2.2 Matrix OSD Binder Applied to Cotton Fabric 214

8.2.3 P2i Process 3 Treatment 222

8.2.4 FRN6 Treatment 230

8.2.5 F-01 Treatment 237

8.3 Conclusions 244

8.4 References 245

Chapter 9 Conclusions and Future Work 246

9.1 Summary and Conclusions 246

9.2 Future Work 250

Counted words: 45,037

List of Figures

6

List of Figures

Figure 1.1 Scanning electron micrograph of cotton fibres 26

Figure 1.2 Morphology of the cotton fibre [17] 26

Figure 1.3 Cellulose polymer 27

Figure 1.4 Chemical synthesis of PET 32

Figure 1.5 Winch dyeing machine 37

Figure 1.6 Jig dyeing machine 37

Figure 1.7 Beam dyeing machine 38

Figure 1.8 Jet dyeing machine 39

Figure 1.9 Continuous dyeing equipment 40

Figure 2.1 CI Pigment Red 1 Para Red 51

Figure 2.2 Copper phthalocyanine 52

Figure 2.3 CI Pigment Violet 19 53

Figure 2.4 Brilliant sulfoflavine FF (yellow) 53

Figure 3.1 AATCC crockmeter 74

Figure 3.2 Grey scale assessment for staining 75

Figure 3.3 Grey scale for assessing colour change 76

Figure 3.4 Schematic of a typical SEM 83

Figure 4.1 Effect of varying the concentration of the formulation applied to cotton

fabric on the KES-F bending stiffness, B 93


fabric on the KES-F bending stiffness, B 97


fabric on the KES-F shear stiffness, G 98


fabric on shear hysteresis at 5o, 2HG5 98

Figure 4.7 SEM micrographs of untreated cotton 99

Figure 4.8 SEM micrographs of 9 g/L binder covered cotton 99

Figure 4.9 SEM micrographs of 90g/L binder covered cotton 100

Figure 4.10 SEM micrographs of 135 g/L binder covered cotton 100

Figure 4.11 SEM micrographs of yellow dyed cotton at a stock formulation

concentration of 10g/L 101


concentration of 100 g/L 101



Figure 4.14 SEM micrographs of red dyed cotton at a stock formulation concentration

of 10g/L 102


List of Figures

7

of 100g/L 103


of 150g/L 103

Figure 4.17 SEM images of blue dyed cotton at stock formulation conc.10g/L 104

Figure 4.18 SEM micrographs of blue dyed cotton at a stock formulation



concentration 150g/L 105

Figure 4.20 SEM micrographs of abraded red dyed cotton 105

Figure 4.21 Effect of softener incorporated into binder system on the bending stiffness,

B, of pigment dyed cotton fabric 111

Figure 4.22 Effect of softener incorporated into binder system on the shear stiffness,

G, of pigment dyed cotton fabric 111

Figure 4.23 Effect of softener incorporated into binder system on the shear hysteresis

at 5o, 2HG5, of pigment dyed cotton fabric 112

Figure 5.1 Effect of varying the cationic fixing agent concentration on the colour

strength of pigment dyed cotton fabric 122

Figure 5.2 Effect of UVO exposure on the colour strength of pigment dyed cotton

fabric 134

Figure 5.3 SEM micrographs of 5 minutes-UVO treated red dyed cotton at 10g/L

stock formulation concentration 135

















Figure 6.1 Effect of varying FC3548 concentration on the colour strength of

increasing concentrations of pigment formulation applied to cotton fabric 150

Figure 6.2 Effect of varying FC3548 concentration on the colour strength of pigment

dyed cotton fabrics 150

Figure 6.3 SEM micrographs of 5g/L FC3548 treated red-dyed cotton at a stock

List of Figures

8

formulation concentration of 10g/L 151























Figure 6.15 Effect of varying F-01 concentration on the colour strength of pigment

dyed cotton fabrics 156

Figure 6.16 SEM micrographs of 20g/L F-01 treated red-dyed cotton at a stock

















List of Figures

9



dyed polycotton fabrics 161

Figure 6.26 Effect of varying FRN6 concentration on the colour strength of pigment

dyed cotton fabric 165

Figure 6.27 Effect of varying FRN6 concentration on the bending stiffness of red

pigment dyed cotton fabric 165

Figure 6.28 Effect of varying FRN6 concentration on the shear stiffness of red


Figure 6.29 Effect of varying FRN6 concentration on the shear hysteresis, 2HG5, of

red pigment dyed cotton fabric 166

Figure 6.30 SEM micrographs of 30g/L F6 treated red-dyed cotton at a stock


















Figure 6.39 Effect of varying P2i treatment on the colour strength of blue pigment


Figure 6.40 Effect of varying P2i treatment on the bending stiffness blue pigment


Figure 6.41 Effect of varying P2i treatment on the shear stiffness of blue pigment


Figure 6.42 Effect of varying P2i treatment on the shear hysteresis, 2HG5, of blue


Figure 6.43 SEM micrographs of P2i process 1 treated blue-dyed cotton at a stock





List of Figures

10

formulation concentration 10g/L 174













Figure 6.52 Effect of varying Oleophobol concentration on the colour strength of blue

pigment dyed cotton fabric (λmax=610nm) 177

Figure 7.1 Effect of plasma pre-treatment on colour strength (λmax=610nm) 187

Figure 8.1 C (1s) XP spectrum of untreated cotton fabric 200

Figure 8.2 C (1s) XP spectrum of 10g/L blue dyed cotton fabric 200



Figure 8.5 C (1s) XP spectrum of 10g/L blue dyed cotton fabric treated with 40g/L

F-01 201


F-01 201


F-01 202


F-01 202


F-01 202


F-01 203

Figure 8.11 C (1s) XP spectrum of washed 150g/L blue dyed cotton fabric treated with

60g/L F-01 203

Figure 8.12 C (1s) XP spectrum of washed & heat pressed 150g/L blue dyed cotton

fabric treated with 60g/L F-01 203


FRN6 204


FRN6 204


FRN6 204

List of Figures

11


FRN6 205


FRN6 205


FRN6 205


60g/L FRN6 206


fabric treated with 60g/L FRN6 206

Figure 8.21 C (1s) XP spectrum of 10 g/L blue dyed cotton treated with P2i Process 1

207

Figure 8.22 C (1s) XP spectrum of 100g/L blue dyed cotton treated with P2i Process 1

207


208


208


208


209


209


209


210

Figure 8.30 C (1s) XP spectrum of washed 150g/L blue dyed cotton treated with P2i

Process 3 210


treated with P2i Process 3 210

Figure 8.32 Typical composition of the linear alkyl benzene sulphonates (LAS) 211

Figure 8.33 (a)-(d) ToF-SIMS positive ion spectra of ECE detergent powder 213

Figure 8.34 (a)-(c) ToF-SIMS negative ion spectra of ECE detergent powder 214

Figure 8.35 Cellulose-specific 214

Figure 8.36 ToF-SIMS spectra of untreated cotton fabric 215

Figure 8.37 (a)-(e) ToF-SIMS positive ion spectra of Matrix OSD binder applied to

cotton fabric 218

Figure 8.38 (a)-(c) ToF-SIMS negative ion spectra of Matrix OSD binder applied to

cotton fabric 219

Figure 8.39 The intensity of the more hydrophobic LAS 220

List of Figures

12

Figure 8.40 (a)-(e) ToF-SIMS positive ion spectra of ISO CO6 washed cotton fabric

with applied Matrix OSD Binder 221

Figure 8.41 (a)-(c) ToF-SIMS negative ion spectra of ISO CO6 washed cotton fabric

with applied Matrix OSD Binder 222

Figure 8.42 (a)-(c) ToF-SIMS positive ion spectra of P2i Process 3 treated cotton

fabric with applied Matrix OSD 225

Figure 8.43 (a)-(c) ToF-SIMS negative ion spectra of P2i Process 3 treated cotton

fabric with applied Matrix OSD 226

Figure 8.44 (a)-(e) ToF-SIMS positive ion spectra of ISO CO6 washed P2i Process 3

treated cotton fabric with applied Matrix OSD 227

Figure 8.45 (a)-(c) ToF-SIMS negative ion spectra of ISO CO6 washed P2i Process 3


Figure 8.46 (a)-(c) ToF-SIMS positive ion spectra of washed and heat pressed P2i

Process 3 treated cotton fabric with applied Matrix OSD 229

Figure 8.47 (a)-(c) ToF-SIMS negative ion spectra of washed and heat pressed P2i

Process 3 treated cotton fabric with applied Matrix OSD 230

Figure 8.48 (a)-(d) ToF-SIMS positive spectra of 60g/L FRN6 treated cotton fabric

with applied Matrix OSD 232

Figure 8.49 (a)-(c) ToF-SIMS negative spectra of 60g/L FRN6 treated cotton fabric

with applied Matrix OSD 233

Figure 8.50 (a)-(c) ToF-SIMS positive ion spectra of ISO CO6 washed 60g/L FRN6


Figure 8.51 (a)-(c) ToF-SIMS negative ion spectra of ISO CO6 washed 60g/L FRN6


Figure 8.52 (a)-(c) ToF-SIMS positive ion spectra of washed & heat pressed 60g/L

FRN6 treated cotton fabric with applied Matrix OSD 236

Figure 8.53 (a)-(c) ToF-SIMS negative ion spectra of washed & heat pressed 60g/L

FRN6 treated cotton fabric with applied Matrix OSD 237

Figure 8.54 (a)-(c) ToF-SIMS positive spectra of 60g/L F-01 treated cotton fabric with

applied Matrix OSD 239

Figure 8.55 (a)-(c) ToF-SIMS spectra of 60g/L F-01 treated cotton fabric with applied

Matrix OSD 240

Figure 8.56 (a)-(c) ToF-SIMS positive ion spectra of ISO CO6 washed 60g/L F-01


Figure 8.57 (a)-(c) ToF-SIMS negative ion spectra of ISO CO6 washed 60g/L F-01



F-01 treated cotton fabric with applied Matrix OSD 243


F-01 treated cotton fabric with applied Matrix OSD 244

List of Tables

13

List of Tables

Table 1.1 Physical & chemical properties of polyester fibres 31

Table 2.1 A comparison of the general characteristics of dyes and pigments 49

Table 3.1 Test intervals for abrasion testing 77

Table 3.2 Parameters measured in the Kawabata Evaluation System 79

Table 3.3 Range of test liquids with decreasing surface tension for the oil-repellency

test 81

Table 3.4 Range of test liquids employed with decreasing surface tension 81

Table 4.1 Concentration of stock formulations 90

Table 4.2 Concentration of stock formulation 90

Table 4.3 Effect of varying the concentration of the formulation applied to cotton

fabric on the wet/dry rub fastness 92


fabric on the colour strength 92


fabric on the rub and wash fastness 96


fabric on the colour strength 96


fabric on the Martindale flat abrasion 97

Table 4.8 Effect of varying the concentration of the pigment formulation applied to

cotton, PET and polycotton fabrics on the fastness 106


cotton, PET and polycotton fabrics on the colour strength 106

Table 4.10 Effect of different curing times on the fastness of yellow pigment dyed

cotton fabric 107

Table 4.11 Effect of different curing times on the fastness of red pigment dyed cotton

fabric 108

Table 4.12 Effect of different curing times on the fastness of blue pigment dyed cotton

fabric 109

Table 4.13 Effect of varying concentration of formulation applied to cotton fabric on

rub and wash fastness 110


colour strength 110

Table 5.1 Effect of varying the cationic fixing agent concentration on the fastness of


Table 5.2 Effect of 2% o.w.f. application of Nanolink on the fastness properties of of


Table 5.3 Effect of citric acid pre-treatment of cotton on the fastness of the yellow

pigment dyed fabric 124

List of Tables

14

Table 5.4 Effect of citric acid pre-treatment of cotton on the fastness of the red


Table 5.5 Effect of citric acid pre-treatment of cotton on the fastness of the blue


Table 5.6 Effect of the application of Knittex MLF New pre-treatment to cotton on the

fastness of pigment dyed fabric 127

Table 5.7 Effect of incorporating Knittex MLF New into the pigment dyeing

formulation applied to cotton fabric on colour fastness 128

Table 5.8 Effect of pre-treatment with citric acid and Knittex MLF New on the

fastness performance of yellow pigment dyed cotton fabric 129


fastness performance of red pigment dyed cotton fabric 130


fastness performance of blue pigment dyed cotton fabric 131

Table 5.11 Effect of 100g/L DMDHEU pre-treatment on the fastness performance of


Table 5.12 Effect of UVO treatment on the fastness performance of pigment dyed

cotton fabric 133

Table 6.1 Concentration of Shield F-01aftertreating system 144

Table 6.2 Effect of varying FC3548 concentration within the pigment dyeing

formulation on the fastness of coloured cotton fabric 148

Table 6.3 Effect of varying FC3548 concentration on the fastness performance of red


Table 6.4 Effect of FC3548 concentration on the Martindale Flat Abrasion

performance of pigment dyed cotton fabrics 149

Table 6.5 Effect of varying F-01 concentration on the fastness of pigment dyed cotton

fabrics 155

Table 6.6 Effect of varying F-01 concentration on the water and oil repellency of

pigment dyed cotton fabrics 156

Table 6.7 Effect of varying F-01 concentration on the fastness of pigment dyed

polycotton fabrics 160

Table 6.8 Effect of varying FRN6 concentration on the fastness performance of


Table 6.9 Effect of varying FRN6 concentration on the flat abrasion of pigment dyed

cotton fabric 164

Table 6.10 Effect of varying FRN6 concentration on the water and oil repellency of

red pigment dyed cotton fabric 164

Table 6.11 Effect of varying P2i treatment on the fastness of blue pigment dyed cotton

fabric 170

Table 6.12 Effect of varying P2i treatment on the water and oil repellency of blue


Table 6.13 Effect of varying Oleophobol concentration on the fastness of blue

List of Tables

15


Table 6.14 Effect of varying Oleophobol concentration on the water and oil repellency

of blue pigment dyed cotton fabric 177

Table 6.15 Water and oil repellency of cotton fabric treated with fluorocarbons and

subsequently washed and heat pressed 178

Table 6.16 Abrasion resistance on cotton fabric treated by fluorocarbons 179

Table 6.17 Water and oil repellency of red pigment dyed cotton treated with F-01 and

FRN6 fluorocarbon finishes 180

Table 6.18 Water and oil repellency of plain untreated cotton and red pigment dyed

cotton treated by Rucoguard LAD and Oleophobol 7713 by exhaustion and padding

applications 181

Table 7.1 Plasma treatment conditions 185

Table 7.2 Effect of plasma pre-treatment on colour fastness 186

Table 7.3 Effect of plasma after-treatment on heat cured yellow pigment dyed fabric

fastness 189

Table 7.4 Effect of plasma after-treatment on heat cured red pigment dyed fabric

fastness 190

Table 7.5 Effect of plasma after-treatment on heat cured blue pigment dyed fabric

fastness 191

Table 7.6 Effect of plasma after-treatment on uncured yellow pigment dyed fabric,

followed by heat curing, fastness 192

Table 7.7 Effect of plasma after-treatment on uncured red pigment dyed fabric,


Table 7.8 Effect of plasma after-treatment on uncured blue pigment dyed fabric,


Table 8.1 XPS surface elemental composition of blue pigment dyed cotton fabric

treated with fluorocarbons 199

Table 8.2 ToF-SIMS Fatty alcohol ethoxylates ion assignments 212

Table 8.3 Polyacrylate positive ion assignments 216

Table 8.4 Poly(acrylate) negative ion assignments 217

Table 8.5 PDMS (-[(CH3)2SiO]n-) ion assignments 217

Table 8.6 Positive fluorocarbon species 224

Table 8.7 Negative fluorocarbon species 224

Glossary of Terms

16

Glossary of Terms

Polyethylene terephthalate PET

Polylactic acid PLA

Kawabata Evaluation System KES

Scanning Electron Microscopy SEM

X-ray Photoelectron Spectroscopy XPS

Time-of-Flight Secondary Ion Mass Spectrometry ToF-SIMS

Dimethylol Dihydroxy Ethylene Urea DMDHEU

Ultraviolet/ozone UVO

Abstract

17

Abstract

University of Manchester

Qingqing Cao

Doctor of Philosophy (PhD)

An investigation of environmentally friendly pigment colouration

12th

, February 2013

This research has investigated the modification of cotton fabric and pigment dyeing

system in order to improve the colouration properties, such as rub fastness, wash

fastness, colour strength and fabric handle of the textile material. It involved four

different approaches based on pre-cationization of the fabric, incorporation of

crosslinkers into the binder formulation, UVO pre-treatment of the fabric, and wet

fluorocarbon treatment and dry plasma polymerisation treatments.

It has been reported that the Matrix OSD pigment dyeing system offers benefits in

terms of processing cost and environmental impact and from the initial studies it was

apparent that while dry rub fastness, mechanical rigidity and washing performance

were generally acceptable the wet rub fastness of the printed fabrics presented a

technical challenge. Therefore in this study the colour wet rub fastness was regarded

as the main performance indicator to be targeted and improved. Cationizing the

cotton fabrics prior to pigment dyeing improved the wet rub fastness performance of

the Matrix OSD dyeing system, while the other fastness properties were in general

unchanged. Similarly crosslinking treatments enhanced the colour fastness

performance, due to the improvement of the bonding between the binder and fabrics.

The crosslinking/crease resist pre-treatment offers better performance than the

combined application method in terms of improving the wet rub fastness. Surface

modification of textile materials is able to modify the textile wettability, adhesion,

dyeability and handle and therefore has been studied with a view to improving the

durability of the surface pigment dyed coating. However in this study the benefits of

a UV/Ozone (UVO) pre-treatment previously observed for other long liquor fabric

dyeing studies of textiles was not observed and it was established that the pigment

dyeing performance was reduced after the sensitised photo-oxidation treatment. The

investigation demonstrated that the fluorocarbon treatments had a beneficial effect

on colour wash fastness and wet rub fastness, while dry rub fastness was marginally

reduced at higher fluorocarbon application levels. Different fluorocarbons were

examined in this study, and the aftertreatment with Shield F-01 and Shield extender

FCD offered the best results. A range of plasma pre-treatments prior to pigment

dyeing were also examined but only a marginal benefit on the colour fastness

properties and to some extent slightly decreased dry rub fastness was observed. In

contrast the plasma after-treatments, using both argon (Ar) and nitrogen (N2)

atmospheres, improved the fastness, particularly wet fastness, particularly when the

binder heat curing process was before plasma after-treatment.

Declaration

18

Declaration

No portion of this work has been submitted in support of any application for another

degree or qualification of this or any other University or other institution of learning.

Qingqing Cao

Copyright Statement

19

Copyright Statement

Copyright in text of this thesis rests with the Author. Copies (by any process)

either in full, or of extracts, may be made only in accordance with instructions

given by the Author and lodged in the John Rylands University Library of

Manchester. Details may be obtained from the librarian. This page must form part

of any such copies made. Further copies (by any process) of copies made in

accordance with such instructions may not be made without the permission (in

writing) of the Author.

The ownership of any intellectual property rights which may be described in this

thesis is vested in the University of Manchester, subject to any prior agreement to

the contrary, and may not be made available for use by third parties without the

written permission of the University, which will prescribe the terms and

conditions of any such agreement.

Further information on the conditions under which disclosures and exploitation

may take place is available from the Head of School of Materials.

Acknowledgements

20

Acknowledgements

I would like to thank my supervisors Professor C. M. Carr and Dr M. Rigout for

their valuable advice, guidance and encouragement during my study.

I am very grateful to the support of Mr. Phil Cohen and Mr. David Kenyon for their

really helpful suggestions and patience. I would also thank Ms Xiangli Zhong for

her excellent SEM training session and suggestions in the SEM analysis. I would

like give special thanks to Ms Alison Harvey for the KES handle properties and XPS

studies which required great patience.

I would like to thank my parents. I would give my greatest gratitude for my mother’s

support, encouragement and love. I would thank all my friends in Manchester for all

those lovely memories.

Chapter 1 Textile Colouration

21


1.1 Definition

Textile colouration mainly involves textile printing, textile dyeing and mass

pigmentation of synthetic filaments during melt spinning [1]. Dyeing and printing of

textile materials typically relies on the transfer of dye chromophoric molecules from

the application medium, such as aqueous dye solutions or print pastes, and diffusion

of the colourant into the fibres [1, 2]. In contrast pigments can be bound to the fabric

structure by a polymeric binder, in pigment print or dyeing, or incorporated inside

the filament during mass pigmentation.

Textile printing is a process to pattern a fabric by applying colourant (dyes or

pigments) and other auxiliary chemicals, usually in a repeated structure [3]. Textile

dyeing, unlike textile printing, refers to the colouration of the entire fabric, while

printing is just a particular area patterning and normally a one-sided effect. Dyeing

can be described as the process of applying a comparatively permanent colour to

fibre, yarn or fabric by immersing in a bath of dye [4]. Dyeing is double-side

coloured while printing is usually one-side coloured.

1.2 History

The textile industry is considered as one of the largest global industries, and if all

aspects of the diverse textile supply chain are taken into account, it is recognised that

the textile industry involves more people and more assets than most other

manufacturing industries. At the same time, the textile industry is also one of the

oldest industries [5]. Archaeological evidence indicates that fine quality textiles were

produced thousands of years ago, long before the oldest preserved written documents

first mentioned them. The ancient history of textile fibres and fabrics has been shown


22

by such archaeological discoveries as spinning whorls, distaffs, loom weights, and

fragments of fabrics found in the Swiss lake regions and Egyptian tombs [5].

As an integral part of the textile aesthetics and functionality, colouration is as old as

textiles themselves. The origins of textile dyeing are uncertain, but some coloured

fabrics which were dyed yellow, a colour obtained from the safflower plant, were

discovered in ancient Egyptian tombs from about 3500 BC [2, 6]. Until 1856, all dyes

were made from natural materials, mainly animal and vegetable sources, with a few

minerals being used for special colours. Then in 1856 Sir William Henry Perkin, when

trying to create artificial quinine from coal tar, happened to produce the first synthetic

dyestuff, a purple basic dye, mauveine. Nowadays almost all commercial dyes are

manufactured synthetically with the synthetic derivatives being superior in most

performance aspects when compared to natural dyes [5].

It is likely that the ancient dyeing originated from India [2, 6] where at that time,

soaking fabric in aqueous natural colourant plant extracts was the primary dyeing

method. Consequently, the range of colours was limited, the hue was dull and the

products invariably had poor wash fastness and light fastness [7]. In the

mid-seventeenth century, because of the development of systematic quality control in

the French dyeing industry, textile dyeing gained a new momentum which during the

eighteenth and early nineteenth centuries provided a greater understanding and

associated scientific methodology. This new enlightened and better informed

approach has continued with general advancements in the broader scientific field [8].

As an important component of overall garment appearance, the influence and

development of textile printing has played a critical role in the history of clothes and

their aesthetics. In ancient times, natural substances like charcoal and coloured earths

(ochres) were used as printing paste with oils and fats, and applied as a kind of paste


23

with people’s hands to decorate their body, caves and containers [9]. The origin of

earliest textile printing has not yet been established, but it is likely it originated from

China, India, Egypt or the East. Unfortunately, the sole early examples of printed

textiles have only survived on account of the dryness of the Egyptian environment

while in other climates have degraded quickly. In reviewing the various printing

processes, there are three stages that may be distinguished in the historical

development of textile printing. The first stage is simple hand printing of dyestuffs to

form the design pattern, or alternatively painting on a fabric first with a special resist

chemical, which can form a barrier to the dyestuff, and then dyeing the whole fabric

apart from the “protected” areas (resist printing). The second stage consists of a wide

range of techniques for the purpose of taking the artist’s original artwork and

reproducing it more rapidly. In this stage, the dyeing processes are manual and

semi-automatic, such as the surface (block), intaglio and screen methods. The most

advanced stage involves an enormous increase in the degree to which mechanisation

is utilised, such as the fully automatic screen printing and ink jet printing [10].

1.3 Classification

1.3.1 Textile printing

There is no classification system for textile printing. However, it can be broadly

categorised into four different styles: direct, discharge, resist and mordant style. Of

these, the last two processes are the oldest [3].

The principle of direct printing is to print directly onto the white or pre-dyed fabric.

Therefore, the printed pattern is usually much deeper in colour than the background.

It is the most common method in the textile industry, especially in terms of pigment

printing. It does not require any pre-treatment or application of mordant to the fabric

and fixation is achieved just by steaming or dry baking [11].


24

Secondly, the discharge style is a process involving dye destruction which replaces

the original colour by a white or coloured pattern. Therefore in this process it is

necessary to dye the fabric first and then apply the discharge paste on specified area,

pre-determined for the design [9]. There are several factors that are necessary to

consider when patterning: the type of dyes needed to colour the background, the

discharging agent to choose in the illuminating areas, the associated print auxiliaries

and their effect on the final print, and finally the type of thickener required to control

the discharge chemicals and dyes [11].

Thirdly, the resist style produces a visual effect which is almost the same as in the

discharge style. Consequently, it can be difficult to distinguish them. However, the

printing process of resist style is opposite to the discharge style. The motif is printed

on the fabric with the resist agent, which may be composed of rice paste, clay or

some type of wax prior to colouration. In this way, the colour is just dyed on the area

not covered by resist agent [9]. Either a white resist or a coloured resist can be

achieved in this style.

Lastly, the mordant style is different from the resist style because here, the colour

adheres only to the area where the mordant has been applied. For the colourants

which are obtained from animals and vegetables, a fixing agent (mordant) needs to

be used in conjunction with colourant. Once the fabric was dyed, only the area to

which mordant was applied area formed an insoluble colour after fixation, whereas

the non- mordanted parts were washed clear and clean in water [3].

1.3.2 Textile dyeing

Textile material colouration can be achieved in a number of different ways, and

classifications can be made mainly by the categories of dye used [7, 12]:


25

In direct dyeing the dye in the aqueous solution in contact with the material is

gradually absorbed into the fabrics due to its inherent substantivity for the fibre. This

type of dyeing includes the following dyes: acid dyes, direct dyes, basic dyes,

reactive dyes, and disperse dyes.

Alternatively, dyeing can be achieved with a soluble derivative of the dye, which

forms an insoluble pigment within the fibres following the appropriate treatment

after dyeing. This category encompasses: vat dyes and sulphur dyes. Moreover the

water soluble uncoloured precursors can be adsorbed into the fibre and for the

insoluble dye stuff in situ, i.e. the azoics.

Lastly, pigmentation is a process whereby pigment is bound to the surface of the

fibres through the use of an appropriate binder or by mass pigmentation in synthetic

fibres [7, 12].

All of these methods, except the last, require that the fibres, at some stage, absorb

the dye or an appropriate precursor from a dyeing solution. This absorption process

is essentially reversible. However, pigmentation and covalent bonding of the

reactive dye with appropriate functionalities, such as hydroxyls in the fibre are

irreversible processes [7].

1.4 Textile colouration of cotton

1.4.1 Cotton fibres

Cotton fibres are related to mallows, hollyhocks, and hibiscus, and all kinds of the

mallow family (Malvaceae) [13]. The word cotton is derived from Arabic, Qutun or

Qoton, which refers to a “plant found in a conquered land”. It is the purest

cellulose-based plant in nature [14]. Representing one of the most useful natural


26

fibres, cotton production occupied 42.8% of the whole world fibre production [15].

The complex structure of cotton fibres only becomes apparent when observed under

an optical or electron microscope. The cotton fibre has a flat ribbon-like structure

with occasional convolutions along its length, as shown in Figure 1.1. These prevent

parallel fibres from sliding off each other, thus imparting the strength of the yarns

when they are spun together [2].

Figure 1.1 Scanning electron micrograph of cotton fibres

The morphology of the cotton fibre can be differentiated into four parts: the cuticle,

the primary wall, the secondary wall and the lumen, Figure 1.2 [16].

Figure 1.2 Morphology of the cotton fibre [17]


27

The cuticle covers the primary wall with a waxy film which is composed of fats,

waxes and pectin. It is degraded and more or less removed during scouring and

bleaching processes in order to improve the water-absorbent properties [18]. The

majority of the fibre (about 90%) is formed by the secondary wall, which essentially

consists of three layers. The first two, which are next to the primary wall, consist of

entwined cellulosic fibrils of varying pitch. In some cotton fibres, there is also a thin

third layer which consists of mineral salts and proteins [19]. The lumen is the central

vacuole which is used by the growing fibre to provide nutrients and deposit cellular

wastes. Due to the evaporation of the sap, the components dry out and impart the

colour of the cotton fibre. The lumen then collapses and imparts to the cotton fibre

its characteristic ‘kidney bean’ shape [17].

Linear cellulose polymer is the major component of the cotton fibre, typically 65-70%

crystalline and 30-35% amorphous, with cellobiose consisting of two glucose units,

the repeating unit of the cotton cellulose polymer [14]. The degree of polymerization

of cotton cellulose ranges from 6,000 to 10,000.

Figure 1.3 Cellulose polymer

1.4.2 Colourants for cotton

Cotton fabric can be coloured using a relatively large range of colourant classes

including pigments, direct, reactive, sulphur, azoic and vat dyes [17]. Each class has

its own performance and application advantages and disadvantages. However, a key

factor in the success of the colouration process is to ensure that the fabric has been

well-prepared for the purpose of removing surface impurities, ensuring uniform


28

uptake of the dye, good dye penetration into the fibre and avoiding any non-uniform

faults. Most of the deficiencies in the cotton fabric preparation will become more

apparent after dyeing and printing and cause commercial problems. The essential

desizing, scouring and bleaching operations are applied to the cotton fabrics to

remove the impurities [17]. Mercerisation is also considered as a useful treatment to

achieve fabric colouration uniformity and obtain a deeper shade by increasing the

uptake of dye [17].

Pigment printing is suitable for most types of fabric compositions, so accordingly it

is a very common colourant in textile dyeing and printing. Pigments are used in two

ways to colour fabrics. For colouring cotton, they are used together with binding

polymers to achieve a localised surface colouration, but also to some extent in so

called “pigment dyeing” where all areas of the fabric are treated [12].

Direct dyes are soluble anionic dyes which have substantivity for cellulosic fibres,

and are mostly applied from an aqueous dye bath with an electrolyte such as sodium

chloride [17]. They consist of an aromatic structure which contains one chromogen,

an auxochrome and typically several solubilizing groups. Direct dyes were the

earliest dyes to dye cellulosic fibres directly with no pre-treatment of the fibres with

a mordant, hence their description as “direct” dyes. The major groups of the direct

dyes are disazo and trisazo derivatives [20]. As one of the most easily applied dyes

for cotton, direct dyes are widely used as ‘fashion’ dyes where high performance is

not demanded. The cost of direct dyes is relatively low and the spectral range of

colours is relatively large. Their fastness properties, however, are in general low, in

particular the wet fastness. Nevertheless the fastness properties of direct dyes can be

improved by the diazotisation of the dye, crease resist treatment of the direct dyed

fabric, after coppering of the dyed substrate and a cationic fixing agent

aftertreatment of the direct dyed fabric [17].


29

Reactive dyes are different from other dye application classes in that they can react

chemically with cellulosic fibres by forming covalent bonds. In order to facilitate

and maximise the covalent bonding alkali is commonly added to the aqueous

processing media. The amount of reactive dye, which can exhaust into the cotton

fibres, is related to their substantivity. They are not required to have low solubility in

water to achieve great fastness but rather need to be highly substantive to the

cellulosic fibres. Therefore, reactive dyes can be designed to be relatively small,

simple molecules. In fact, their relatively low molecule weight is often beneficial, in

order to achieve good penetration and uniformity within the fibres before chemical

reaction [19]. However despite “chemical engineering” the reactive dye 50% of the

cost of dyeing is still spent on washing off unfixed dye and effluent treatment.

Reactive dyes provide a comprehensive range of colours with good brightness,

excellent wash fastness, stability to peroxide bleach and moderate to very good light

fastness. However reactive dyes are comparatively expensive dyes [17].

Vat dyes are mainly divided into two chromophore categories, the anthraquinonoid

dyes and the indigoid dyes, with both offering a wide range of molecular structures

[19]. Vat dyeing is the process where a water insoluble aromatic keto-substituted

colourant is reduced by alkali and a reductive agent to form a water soluble leuco

compound which is substantive to cellulose. This reduced product will penetrate into

the fibre, and it is then re-oxidised back to the original insoluble form. Two or more

keto (C=O) groups, which are separated by a conjugated system of double bonds,

typically occur in the dye. There are highly condensed aromatic ring systems in most

of the anthraquinone derivatives. Indigo is a relatively poor performance dye and its

substantivity to cellulose is lower than other dyes but nevertheless due to its

widespread use in fashion garments is still widely used.

Similar to vat dyes, sulphur dyes are low solubility dyes which are applied as water


30

soluble reduced leuco compounds under alkali conditions. In this case during the

dyeing process only sodium sulphide is incorporated to act as both an alkali and

reducing agent. Sulphur dyes are similarly widely used in view of the fact that they

provide a combination of a comparatively simple method to dye cellulosic coupled

with good-to-excellent wash and light fastness at a low cost. Their price is lower

than vat dyes, and they are usually used to impart deep colour shades to cotton.

Typically the shades are confined to black, mauves, olives, Bordeaux and reddish

browns [21]. The main drawbacks of sulphur dyes are their spectral limitation to dull

colours, and their relatively poor light fastness and stability to peroxide in pastel

shades [20].

1.5 Textile colouration for polyester

1.5.1 Polyester

As opposed to cotton as a natural fibre, polyester is an important class of synthetic

fibres. Polyethylene terephthalate and cellulose acetates are the most important

polyesters from a commercial point of view, with polyethylene terephthalate (PET)

being the most widely used fibre in the manufacturing of textile products because of

its good performance properties. However, PET is derived from fossil fuel for its

raw materials, which are the main cause of greenhouse emissions and in addition the

disposal of synthetic fibres creates carbon dioxide after incineration. It is the carbon

dioxide emissions which contribute significantly to global warming. Environmental

concerns call for materials which are developed from renewable resources and in the

textile sector biodegradable polyesters such as Poly (lactic acid) (PLA) are regarded

as potentially significant in addressing these concerns [22].

Generally, good physical and chemical properties are required for textile fibres

during processing and in domestic end-use. Physical properties are principally


31

concerned with the mechanical aspects, which include tensile, tear and bursting

strength while chemical properties reflect the stability of fibres during processing

and during their use, in particular the thermal and hydrolytic processes. Table 1.1

details the physical and chemical properties of several kinds of polyester fibres [23].

Polyesters are produced with raw materials from various sources, for example, the

first polyester, acetate rayon, was manufactured from the acetylation of cellulose and

although still produced, their output has decreased.

Table 1.1 The physical and chemical properties of polyester fibres

Property PET PCDT 2o Acetate 3

o Acetate PLA

Chemical

class Aromatic

Aromatic-

Aliphatic

Modified-

carbohydrate

Modified-

carbohydrate Aliphatic

Specific

gravity 1.39 1.23 1.30 1.32 1.25

Tenacity

(gm/d) 2.4 ~ 7.0 2.5~3.5 1.1~1.3 1.2~1.4 2.0 ~ 6.0

Elastic

Recovery

(5% strain)

65% ---- 45 – 65 % 50 – 65 % 93%

Glass

Transition

Temperature

(Tg) ℃

125 ---- ----- ----- 55~60

Melting

Temperature

(™) ℃

255 290 232 300 130 ~

175

LOI (%) 20 ~ 22 ---- ---- ---- 26 ~ 35

Refractive

Index 1.54 ---- ---- ----

1.35 ~

1.45

Moisture

Regain (%) 0.2 ~ 0.4 0.4 6.5 4.5 0.4 ~ 0.6

UV

Resistance Fair ---- ---- ---- Excellent

Alkali

Resistance Good Good

Little effect up

to pH 9.5

Attacked by

strong alkalies Poor

Acid

Resistance Good Good

Strong acids

decompose

Strong acids

decompose Fair


32

1.5.1.1 Poly (ethylene terephthalate) Fibres

PET fibres are produced for the varying requirements of textile applications, such as

mono-filament, multi-filament, staple fibre and tow in a wide range of counts and

staple lengths. These fibres are available in bright, semi-dull and dull lustres and

usually produced in circular cross-section. Crimped and textured yarns can also be

also made since PET is a thermoplastic [23, 24].

Poly (ethylene terephthalate) is created by the condensation polymerization of

ethylene glycol and terephthalic acid or dimethyl terephthalate, Figure 1.4. When the

polymerization has achieved a certain polymer length, the polymer is extruded into an

endless ribbon and then cut into small pieces. After being melted in an inert

atmosphere at 260℃, these chips are extruded into continuous filaments which are

stretched to about five times their original length in order to achieve the required

mechanical strength [23, 24].

Figure 1.4 Chemical synthesis of PET

1.5.1.2 Poly (lactic acid) Fibres

Polylactic acid (PLA) is the first melt-spun fibre where the raw material is obtained

from sustainable resources and is a rigid thermoplastic aliphatic polymer [25]. PLA

molecules have a helical structure, the reversed carbonyl functional groups, and it can

be semi-crystalline or completely amorphous, depending on the stereo-purity of the

polymer backbone [26].


33

PLA mostly behaves like PET, but also performs similarly to the polyolefin

polypropylene (PP). Therefore PLA usage can cover a wide range of applications

due to its ability to be modified by stress and heat, impact modified, filled,

copolymerized, and processed in most polymer processing equipment. It can be

manufactured into transparent films, fibres and injection bottles. PLA can also be

used as an excellent material relating to food contact and related packaging

applications [27].

1.5.2 Dyeing polyester

Since polyester fibres are hydrophobic and do not swell in water, penetration by

water and water-soluble dyes is difficult. Against this background, the development

of disperse dyes was a logical solution to the colouration of polyester fibre. Disperse

dyes are typically non-ionic, sparingly soluble in water even at a very high

temperature of 130℃ and held in aqueous dispersion by surface-active agents [2,

28]. These types of dyes exhibit good light fastness, variable heat fastness and good

wash fastness [20]. Polyester fibres are essentially undyeable below 70-80℃, and

accordingly atmospheric dyeing below 100℃ can only be achieved using carriers [2,

18]. The other alternative is to dye polyester at temperatures above 100℃ using

pressurised vessels. Temperatures as high as 140℃ are used and results in the

amorphous molecular structure of polyester becoming more “open and mobile” and

the diffusion of dye into the fibre is faster and commercially acceptable [2].

When polyester is dyed by disperse dyes, some of the dye is deposited on the

fibre/fabric surfaces. It is essential to remove these residual dyes otherwise the washing

and rubbing fastness of the dyed fabric could be decreased and cross-staining could

increase during laundering. Normal washing or soaping is not strong enough to remove

the surface deposits due to the “insolubility” of disperse dyes. Accordingly a reduction

clear, based on an alkaline reductive treatment, is commercially utilised [29, 30].


34

Sodium dithionite and sodium hydroxide are the most widely used reducing agent.

Some of recently introduced commercial disperse dyes do not require a reductive

environment. They are termed as “Alkali clearable” since alkaline scouring conditions

are sufficient to remove them [7, 31, 32].

In addition to using disperse dyes colouration of polyester can be achieved

incorporating pigments in the mass pigmentation process during fibre extrusion.

Typically the pigments are dispersed in the molten polymer immediately prior to its

extrusion. The pigments which are used for this process must be stable even under

the high temperatures employed in extrusion (about 230℃) [19].

1.6 Machinery

1.6.1 Dyeing machinery

A wide range of machines are available for the dyeing of textile fabrics due to the

fact that textile materials can be dyed at different stages of manufacture, and can be

processed batchwise, semi-continuously and continuously. The dyeing process can

be applied at the loose fibre, tow, yarn, fabric or garment stages. The choice of at

which stage of manufacture to dye, depends on various factors, undoubtedly the

most important of which are cost and fashion considerations. In recent years, late

stage dyeing has increased enormously in order to avoid over-production of

unpopular colours and to respond quickly to repeat orders of those which are more

popular for those manufacturers [19].

The essential aim of the dyeing process is to transfer the dye molecules from the dye

solution into the fibre in a uniform and efficient approach. The rate of dye taken up

by the fibre is increased by the movement of the dye liquor around the fibres [19].

There are three main processing or mechanical principles usually employed for


35

dyeing textiles: (a) the dye liquor is moved and the textile is stationary; (b) the

textile is moved and the dye liquor has no mechanical movement; (c) both the dye

liquor and the textile move or mechanical agitated [33]. During the dyeing process,

three distinctive stages can be identified: (a) transfer of dye from the bulk solution to

the fibre surface; (b) adsorption of dye onto the fibre surface; (c) diffusion of dye

from the surface in to the fibre [19].

1.6.1.1 Dyeing in the loose fibre form

The main advantage of dyeing textile in loose fibre form is the ease of circulation of

the dye solution through the fibres and the fact that any unlevelness in dyeing can be

randomised during the following carding and spinning procedures. The method has

conventionally been employed more for dyeing wool than cotton or synthetic fibres,

especially the application of acid milling dyes due to their relatively poor migration

properties. However, even in the dyeing of wool, the extent of loose stock dyeing

has been reduced in recent years [19].

The most common types of this kind of machine holds the textile materials in a

tapering pan with perforated inward sloping sides, or in a perforated cage. After the

fibres are gradually packed into the pan, they are wetted and compressed by

screwing down a solid plate which is laid on the fibrous top [7]. Another type of

machine is the radial flow type where the fibres are held in a cage of about 150cm

diameter, with perforated sides and a central perforated column.

1.6.1.2 Dyeing yarn

Yarns can be dyed in two different forms: hank and package. Hank dyeing has

always been carried out on yarns which are inherently bulky in nature, while

package dyeing is used for thinner yarns [19]. Nowadays, most yarns are dyed as

packages, which are wrapped around a series of hollow, perforated vertical spindles


36

set around the circular vessel containing the dye liquor. The whole system is

generally in a cylindrical vessel with a round bottom and lid. Appropriate pumps

drive dye liquor, which is reversed from time to time, up through the hollow spindle

and through the wool packages [2].

1.6.1.3 Dyeing fabrics

A variety of machine types are available for dyeing fabrics and the choice of

machine used depends on the nature of the fibre (e.g. wool, cotton, polyester, etc.)

and the structure of the fabric. At the same time, the quantity of cloth to be dyed will

decide whether a batch or continuous process is employed [19].

Winch dyeing machine

The winch or beck dyeing machine, which is quite simple compared to other dyeing

machines, and is able to function in other wet processing such as scouring, bleaching,

dyeing, washing-off and softening. It is the oldest kind of equipment used for dyeing

fabric [2]. A length of fabric with the ends sewn together forms a continuous rope

and the rope passes through the dyebath driven by two elevated reels and follows to

fall back into the bath. The jockey or fly roller, shown in Figure 1.5, is free-running

to act as a support for the rope while it is pulled forward. The winch reel, over which

the rope of fabric is looped over, is driven and controls the rate of rope

transportation and the amount of pleating where the rope accumulates below and

behind the winch. The fabric rope is held on the winch due to its own weight and

friction that can be improved by covering the winch roller with polypropylene or

polyester tape. Once the fabric drops into the dyebath, it turns fold over and the

pleating and opening action keeps the dye liquor flowing through the fabric [2, 7].


37

Figure 1.5 Winch dyeing machine

Jig dyeing machine

The jig or jigger dyeing machine is one of the oldest types of machine which can

dye a variety of materials in open width, Figure 1.6. It is particularly suited for

fabrics such as satins and taffetas that are readily creased. The open-width fabric is

moved from one roller through the dye liquor at the bottom of the machine and then

onto another roller on the other side. The direction of movement is automatically

reversed when all the fabric has passed through the bath. The dyeing duration is

controlled by the number of passages, which is called ends, through the dye liquor.

Dyeing always consist of an even number of ends in order to ensure uniformity [2,

7].

Figure 1.6 Jig dyeing machine


38

Beam dyeing machine

In theory, beam dyeing is similar to yarn package dyeing but with a single large

package used instead, Figure 1.7. Beam dyeing involves winding fabric onto a

perforated beam and pumping dye liquor through the beam and through the fabric

layers [7]. The machines are usually pressure vessels, which can be operated at high

temperatures. The largest vessels can be 4.5 metres and the internal diameter is

nearly 2 metres, and can accommodate beams with approximate 7000 metres of

fabric [19].

Figure 1.7 Beam dyeing machine

Jet dyeing machine

Jet dyeing machines based on the principles of winch dyeing, were gradually

developed from the 1960s, Figure 1.8. In this kind of machine, the fabric rope is

moved by the high-speed dye liquor injection and the fabric folds around the

machine before passing through the jet to start another cycle. 200-250 m/minute is

the usual fabric speed, but higher speeds can be achieved. A typical complete cycle

of the rope takes about one minute [7, 19].


39

Figure 1.8 Jet dyeing machine

1.6.1.4 Continuous dyeing equipment

The major types of fabrics which are dyed continuously are either 100% cotton or a

blend of cotton/polyester and cotton/viscose. For dyeing cotton or the cotton

component in blends, reactives, vats, sulphurs and directs are usually used, whilst

disperse dyes are used for the polyester. In the dyeing process of blends, the dyes

can be applied either together, when they must be compatible with each other and

with the particular auxiliaries in the dyebath, or separately [19]. Continuous dyeing

of fabrics basically involves padding, drying and fixation, Figure 1.9.

Padding

The fabric is first immersed in the dye solution or dispersion and then passed in

open width through a padding mangle nip to squeeze out the excess dye liquor [2].

The aim of this stage is to mechanically impregnate the fabric with dye and

appropriate dyebath auxiliaries, so uniformity in this process is vital [7]. The

duration of immersion of the fabric in the liquor, the time of contact with the nip

rollers and the pressure that those rollers exert on the cloth are all the aspects


40

affecting the uniformity of the distribution of any chemicals in the padded fabric

[19].

Drying and fixation

After the padding operation, in order to avoid unwanted migration of the dye, it is

required to dry the fabric in a controlled manner. Firstly the fabric is pre-dried,

which involves passing the fabric through a bank of infra-red heaters to remove

about 50% of the water. Then all moisture is removed by a conventional drying

machine, such as cylinder cans [19]. The disperse dye is transferred from the cotton

fibre surface into the polyester by sublimation of the dye during the thermosol

process. A steamer is utilized for the continuous fixation of vat, sulphur, reactive and

direct dyes on cotton, especially in blends with polyester. The padded fabrics pass

through a zone which fills with saturated air-free steam for about 20-60s [7].

Figure 1.9 Continuous dyeing equipment

1.6.2 Printing machinery

There are five major methods to print a fabric: the block, roller, screen, heat transfer

and ink-jet printing systems. Only the heat transfer method is distinctly different

because this printing is transferred from a designed and coloured paper while the

other methods are printed through a print paste medium [19]. Block printing,


41

conventional roller printing and hand-screen printing were the three earliest methods

used, and the ink-jet printing method is a relatively new innovation [33].

Block printing

Block printing usually includes applying the printing paste to the designed surface of

wooden blocks to make an impression on the fabrics, and the process is repeated

with varying design blocks and colours until the pattern is complete. However, today

in commercial textile printing operations, this method is rarely used [19, 33].

Roller printing

Roller printing machines underwent few major changes since the first of these

machines was introduced in the 1780’s. They are extremely durable because the

cylindrical print rollers are copper, in which the design is etched. There are separate

rollers for printing each colour. The fabric passes around a large cylinder which is a

pressure bowl covered by a thick layer, the lapping. A blanket and backing cloth

travel around the lapping under the fabric and provide a resilient backing and

flexible support [2, 19]. The printing paste is shifted from a reservoir or trough onto

the surface of the engraved rolls, and a steel doctor blade completely removes the

colourant on smooth areas of the roller. Under pressure, colour is transferred from

the engraved rolls to the fabric surface.

Screen printing

Screen printing has grown from a specialized, labour-intensive art (hand printing or

silk screening on long tables) to a highly mechanized process, using flat and rotary

screen printing machines. Screen printing is a process in which the printing paste is

transferred to the fabric through a stencil or screen which is usually made of silk,

polyester, polyamide or nickel mesh. For the traditional hand screen printing, the

fabric is rolled out and fixed in place on long tables (up to 100 yards in length)


42

which are covered by waterproof covers. Then the screen is placed on the surface of

the fabric and the printing paste is drawn across the screen in a transverse direction

to the fabric length with a rubber squeegee blade. Different screens are used for

different colours. In rotary screen printing, movement of the screen produces the

dynamic pressure which is “neutralised” by the penetration resistance of the fabric

and flow resistance of the screen [33].

Heat transfer printing

In this kind of printing, a designed and coloured paper is prepared before printing

the fabric. The colourants used on paper are volatile disperse dyes that are capable of

being sublimed at elevated temperature. When the paper is heated and held in

contact with the fabric, the dye is transferred to the textile fabric in the vapour phase

[9].

Ink-jet printing

This type of printing has been developing rapidly in recent years following its

primary use for the colouration of paper and documents, and has been adapted to

print on textiles. This type of printing is illustrated by a non-contact method that

emits drops of ink on the surface of the substrate to be printed, and at the same time

affords high print quality art and high speeds. There are two important types of

ink-jet printers, which are the continuous type characterised by high speed and cost

and the drop-on-demand (DOD) or impulse jet printer [33].

1.7 References

1. Johnson, A. E., The Theory of Coloration of Textiles. 2nd. ed. 1989,

Bradford: Society of Dyers and Colourists.

2. Ingamells, W., Colour for Textiles: A User's Handbook, 1993, Bradford:

Society of Dyers and Colourists. vii,179p.


43

3. Storey, J., The Thames and Hudson Manual of Textile Printing. Rev. edn.

1992, New York, N.Y.: Thames and Hudson. p.192.

4. Cegarra, J., Puente, P., and Valldeperas, J., The Dyeing of Textile Materials:

The Scientific Bases and the Techniques of Application, 1992, Biella:

Textilia. p.703.

5. Joseph, M. L., Introductory Textile Science, 5th ed. 1986, New York; London:

Holt, Rinehart and Winston. xv, p.432.

6. Hall, A. J., A Handbook of Textile Dyeing and Printing, 1955, London:

National Trade Press. vii, p.216.

7. Broadbent, A. D., Basic Principles of Textile Coloration, 2001, Bradford:

Society of Dyers and Colourists. xiv, p.578.

8. Waring, D. R. and Hallas, G., The Chemistry and Application of Dyes, 1990:

Plenum. p.414.

9. Miles, L. W. C., Textile Printing. Rev. 2nd edn. 2003, Bradford: Society of

Dyers and Colourists. X, p.339.

10. Dhariwal, J., An Investigation into the Effect of Pigment Printing on Fabric

Handle, 1996, MSc Thesis, UMIST.

11. Wells, K., Fabric Dyeing & Printing, 1997, London: Conran Octopus. p.192.

12. Carr, C. M., Chemistry of the Textiles Industry, 1995, London: Blackie

Academic & Professional. xiii, p.361.

13. Kassenbe, P., Bilateral Structure of Cotton Fibers as Revealed by Enzymatic

Degradation, Textile Research Journal, 1970. 40 (4), p.330.

14. Joseph, M. L., Joseph's Introductory Textile Science. 6th edn., 1992, Fort

Worth: Harcourt Brace Jovanovich College Publishers. xiv, p.417.

15. Society of Dyers and Colourists and A.A.T.C.C, Colour Index. 3d edn., 1971,

Bradford.

16. Cockett, S. R. and Hilton, K. A., Dyeing of Cellulosic Fibres and Related

Processes, 1961, London: Leonard Hill, p. 417.


44

17. Shore, J., Cellulosics Dyeing, 1995, Bradford: Society of Dyers and

Colourists. ix, p.408.

18. James, W., Practical Textile Chemistry: with Special Reference to the

Structure, Properties and Processing of Wool, 1955: National Trade P. p.259.

19. Christie, R. M., Mather, R. R., and Wardman, R. H., The Chemistry of

Colour Application, 2000, Oxford: Blackwell Science. viii, p.288.

20. Rivlin, J., The Dyeing of Textile Fibers: Theory and Practice, 1992,

Philadelphia: J. Rivlin. xiii, p.220.

21. Parfitt, M., Investigation into the Surface Chemistry of Cotton Fibres, PhD

Thesis, UMIST, 2001.

22. Blackburn, R. S., Biodegradable and Sustainable Fibres, 2005, Cambridge:

Woodhead. xxii, p.546.

23. Cook, J. G., Handbook of Textile Fibres. 5th ed. Edn. 1984, Shildon:

Merrow.

24. McIntyre, J., Synthetic Fibres: Nylon, Polyester, Acrylic, Polyolefin, 2005,

CRC Press.

25. Drumright, R. E., Gruber, P. R., and Henton, D. E., Polylactic Acid

Technology, Advanced Materials, 2000, 12(23): p.1841-1846.

26. Hoogsteen, W., Crystal Structure, Conformation and Morphology of

Solution-spun Poly(L-lactide) Fibers, Macromolecules, 1990, 23(2):

p.634-642.

27. Schmack, G., Biodegradable Fibers of Poly(L-lactide) Produced by

High-speed Melt Spinning and Spin Drawing, Journal of Applied Polymer

Science, 1999, 73(14): p.2785-2797.

28. Bogle, M., Textile Dyes, Finishes and Auxiliaries. Rev. edn. Garland Library

of Textile Science and Technology, v 11977, New York: Garland Pub. xiii,

p.166.


45

29. Nunn, D., The Dyeing of Synthetic Polymer and Acetate Fibres, 1979, Dyers

Co. Publications Trust.

30. Moncrieff, R. W., Man-made Fibres, 1975: Newnes-Butterworths London.

31. Aspland, J., Vat Dyes and Their Application. Textile Chem. Color, 1992.

24(1): p.22-24.

32. Provost, J. R. and Connor, H. G., The Printing of Polyester/Cellulose

Blends‐A New Approach. Journal of the Society of Dyers and Colourists,

1987. 103(12): p.437-442.

33. Vigo, T. L., Textile Processing and Properties : Preparation, Dyeing,

Finishing and Performance, 1994, Amsterdam ; London: Elsevier. xvii,

p.479.

Chapter 2 Pigment Colouration

46


2.1 Definition and overview

Colouration of textiles can be achieved by using a pigment through printing or mass

pigmentation. Unlike dyes which are absorbed into the fibre, pigments due to their

insolubility and their lack of affinity for fibre, when printed, are usually in the form

of dispersions and mixed into the print paste or dyeing solution containing binders,

thickeners and other auxiliaries [1]. Therefore, pigment printing is a physical process,

in which there is no reaction between pigment and fabric. After the printing, drying

and curing processes, unlike other textile colouration processes there is no necessity

for after-washing, which reduces costs and eliminates associated pollution [2, 3].

Pigment dyeing and printing as a part of the wider textile colouration sector is

becoming increasingly popular and important. When printed the print paste includes

thickeners while for pigment dyeing system the thickener is omitted. Further,

pigment dyeing can be subdivided into pigment exhaustion dyeing and pigment pad

dyeing. The early method of pigment dyeing proved to be unsuccessful because of

low exhaustion and poor uniformity, but later alternative auxiliaries were introduced

to improve the pigment dyeing quality [4]. Although of lesser significance today

than pigment printing, pigment dyeing still offers significant potential.

2.2 History

About 30,000 years ago, Palaeolithic man discovered the use of pigments for

decoration and was undoubtedly the easiest and earliest application method for

colouring fabrics. Some of the pigments used were earth pigments, for example,

natural iron oxides and carbon black from soot although early prints tended to be

stiff and easily faded [5]. Millennia later the period following the Second World War


47

was characterized by a concerted period of focused further development of pigment

colourants. However prior to the war in 1937, the first modern pigment printing

system, the Aridye system, was introduced by the Interchemical Corporation, but

there were so many limitations that it was not widely adopted [6, 7]. However

progressively there was a dramatic growth in the use of pigment printing, especially

from the 1960s onward when aqueous dispersions of film-forming binders

composed of self-crosslinking copolymers became established [7]. Subsequently

pigments gradually achieved a dominant position in the textile printing sector with

now more than 50% of all textile prints being pigment-based [1].

2.3 Pigments

2.3.1 Definition

Pigments are particles which are not soluble in typical liquid media which is in

obvious contrast to dyes [3, 8]. However they can be mechanically dispersed in a

specific medium to improve its colour or light-scattering properties [9]. For

pigmentary purposes, the range of particle sizes from very fine colloidal particles

(~0.01μm) to relatively coarse particles (~100.0μm) [10].

2.3.2 History

Discoveries by archaeologists indicate that earth pigments were the earliest

colourants used to decorate both people and their possessions. Earth pigments were

probably first recognized simply because their colours stood out when hard lumps of

rock were examined. Such rocks were smashed and the desirable colour was

extracted. The coloured rocks were then ground to fine powder and blown onto the

painting surface by a hollow tube, or mixed with fatty materials to form a kind of

natural paint which was applied with the fingers or a reed. Some of the prehistoric

cave paintings were based on this methodology and examples are widely distributed


48

around the world due to their high resistance to decomposition by heat, light and

weather. Indeed, without these excellent properties, pigments would not have

survived the many centuries.

Pigments have also been derived from natural colouring matter in many plants and

even in some animals. For example both the red pigment madder and the blue indigo

are extracted from plants, while cochineal and lac lake are derived from insects, the

much-prized Tyrian purple is obtained from certain shellfish, and finally sepia is

obtained from cuttlefish [11].

The era following the Second World War was the golden age for the development of

pigments. The manufacture of inorganic pigments began in the 19th

century, while

the production of organic pigments has always been a part of the dyestuff industry

since pigments became a secondary product of dyestuff manufacturing. Indeed

typically new chromophoric colourant systems were often first used as a pigment

[12].

2.3.3 Dyes and pigments

Colour may be introduced into manufactured objects, such as textiles and plastics, or

into a range of colour application media, such as paints and printing inks, for a

variety of reasons. Yet in most occasions, the ultimate purpose is to decorate and

improve the attractiveness of a product and enhance its market appeal [13]. Colours

are related to the region of the electromagnetic spectrum which can be recognised by

human eyes, that is, the range between 400nm and 700nm in which light is absorbed

at different wavelengths [14]. The resultant colour is generally achieved by the

individual colourants or as a combination of dyes or pigments. The term colourant is

commonly used to encompass both types of colouring materials [13].


49

Dyes and pigments are both commonly produced by the manufacturers as coloured

powders, and they may often be chemically quite similar. However, they are

specifically different in their properties and particularly in the way they are used.

Dyes and pigments are typically distinguished on the basis of their solubility

properties. Essentially, dyes are soluble, whilst pigments are insoluble. A

comparison of the general characteristics of dyes and pigments is presented in Table

2.1 [13].

Table 2.1 A comparison of the general characteristics of dyes and pigments [13]

Property Dyes Pigments

Solubility

Required to have solubility or

capable of solubilisation mainly

in water

Required to resist dissolution in

any solvents

Traditional

applications Textiles, leather, paper Paints, printing inks, plastics

Method of

application

Applied to textile fibres from an

aqueous dyebath solution

Dispersed into a liquid medium

which subsequently solidifies

Main chemical

types

Organic only: azo, carbonyl and

arylcarbonium ion etc.

Organic types: azo, carbonyl and

phthalocyanine; inorganic types

Application

classification

For textile applications, the

subdivision into dye application

classes is important

Pigments are multi-purpose

objects and application class is

relatively unimportant

Colour

properties Full range of coloured species

Include coloured, white and

metallic species

A further difference between dyes and pigments is that while dye molecules are

intended to be attracted strongly to the polymer molecules which constitute the

textile fibre, pigment molecules are not required to present such affinity for their

medium. Pigment molecules are, nevertheless, required to be attracted strongly to

one another in their solid crystal lattice structure in order to resist dissolution in

solvents [13].


50

2.3.4 Classification of pigments

The range of pigments can be divided into three main series according to their

chemical constitution and form of preparation for use: organic pigments

(approximately 60% of the total number of pigment products), water insoluble dyes

(approximately 20% of the total number of pigment products) and inorganic

pigments (approximately 20% of the total number of pigment products) [11].

Generally, organic pigments are characterised by high colour strength and brightness

and variable in the range of fastness properties which they offer. The properties of

pigments temporarily converted into soluble dyes are the same as the organic

pigment due to their organic nature and the reversible nature. Inorganic pigments

generally provide excellent resistance to heat, light, weathering, solvents and some

chemical attack. In these aspects, they have technical advantage over most organic

pigments although they suffer from the disadvantage of considerably lower intensity

and brightness of the colour compared with organic pigments. Additionally

inorganic pigments are usually significantly cheaper than organic-based materials

[13].

2.3.4.1 Organic pigments

Organic pigments are typically non-ionic colourants based various chemical

chromophoric classes [11, 12]. Organic pigments are usually brighter, purer, and

richer in colour than comparable inorganic pigments [10]. They can be treated with a

suitable surfactant and milled in order to reduce and optimise the particle size

(typically 0.03-0.5µm) and improve colour strength/yield [11]. The coloured organic

pigments are mostly used in the form of printing inks, followed by paints and

plastics. They are commonly used to print postage stamps and currency notes, and

different coloured organic pigments can be used to identify and differentiate cable

coatings, gas conduits, electric switches, yellow school buses and so on for safety

reasons [15].


51

Approximately 25% (by weight) of the organic colourant production is comprised of

organic pigments and this share of pigments compared with dyes is increasing. The

classification of organic pigments can be defined as either classical or high

performance pigments. Classical organic pigments mainly consist of azo pigments

and phthalocyanines, which are relatively inexpensive products and used extensively

in a large range of printing ink, plastics and paint applications. High performance

pigments are able to provide greater technical performance, usually at higher cost

and are more sophisticated in nature [13]. Some of the major organic pigments are

discussed in the following sections.

Azo pigments

Of the organic pigments azo compounds are considered as the largest group,

regardless of the number of different chemical structures or of the total production

volume. Normally azo chromophores are synthesised by diazotising a primary

aromatic amine, and then coupling this to a second component, usually a derivative

of beta naphthol, acetoacetanilide or pyrazolone. The commercial colour range

encompasses the yellows, oranges and reds [11]. Typical azo pigment structure, CI

Pigment Red 1 Para Red, is shown in Figure 2.1.

Figure 2.1 CI Pigment Red 1 Para Red

Phthalocyanine pigments

As the first new chromogenic type to be introduced into the field of organic pigment


52

chemistry, the development of phthalocyanine is interesting both technically and

scientifically. Before this discovery, making dyes insoluble and synthesizing new

insoluble azo compounds were the two approaches to develop all organic pigments

[11]. An important constituent in the phthalocyanine range of pigments is copper

phthalocyanine which provides almost all the important blue and green pigments.

Incorporating copper creates a pigment of outstanding resistance, strength and

brilliance of colour [16]. It is widely used in most pigment applications due to its

brilliant blue colour and its excellent fastness to light, heat, solvent, acids and alkalis.

Moreover, despite its structural complexity, copper phthalocyanine has a relatively

low price, Figure 2.2 [13].

Figure 2.2 Copper phthalocyanine

Quinacridone pigments

Quinacridone pigments are generally known generally as linear trans-quinacridones.

The linear trans-quinacridones are infusible or high-melting solids, insoluble in

normal solvents, non-bleeding/migrating and fairly heat resistant as pigments. In

addition, they are chemical resistant to both alkali and acid although their alkali

resistance is not suitable to use directly on concrete or glazed cement-asbestos


53

powders. They have good light fastness, particularly in light tints [11].

Figure 2.3 CI Pigment Violet 19

Fluorescent pigments

Fluorescent pigments are derived from fluorescent dyes which are soluble in certain

polymeric resins. A resin coloured in this manner is based on fluorescent pigment

powder, which is dispersed into the media in the same way as other pigments. The

overall impact is that the paints, printing inks and plastics into which fluorescent

pigments have been combined have very vivid bright colours which attract the eye

[11].

Figure 2.4 Brilliant sulfoflavine FF (yellow)


54

2.3.4.2 Water-soluble dyes

Water-soluble dyes are converted into insoluble dyes by means of various

precipitation techniques. Traditional dyes can be insolubilized by precipitation by

reacting with phosphomolybdic or phosphotungstic acids, or alternatively copper

hexacyanoferrate. These complexes show higher light fastness than their parent

basic dyes or a traditional tannate mordant. Although reducing in importance soluble

dyes can be converted into pigments by precipitation using an inert substrate such as

alumina hydrate [11].

Vat dyes, although they may be intended as pigments in view of their aqueous

insolubility, are typically used as dyes. When they are prepared for dyeing, their

particle size is a significant technical element which influences their rate of

reduction. When vat dyes function as pigments, particle size be even more

important.

2.3.4.3 Inorganic pigments

Inorganic pigments exist as the coloured natural minerals commonly used to

embellish ceramics, glass and many other artefacts [11]. Some of them are

single-component particles, such as oxides, hydroxides or sulphides, while others

are mixed-phase pigments, which contain mixed crystals of oxides or sulphides,

which are distinct from pigments that are pure physical mixtures.

This kind of pigment crystallises as a stable oxide lattice and the colour occurs by

reason of the incorporation of coloured metal cations in a variety of valency states

[17]. Some inorganic pigments are still in use commercially, and they can be

classified further as non-coloured pigments (hiding white pigments, non-hiding

white pigments, black pigments and metallic pigments) and coloured pigments [13].


55

Inorganic pigments play a special role in pigment chemistry for several reasons.

Some of them are relevant to culture heritage and history. For example, the colours

of oil paintings in the art galleries around the world were, until the industrial

revolution, produced entirely from mixtures of inorganic pigments obtained from

natural sources which are so-called earth pigments. Another reason why inorganic

pigments are so important is that there are no white organic pigments. White

pigments are fundamental to provide opacity to the paints and printing inks which

are used on metal, wood, paper, textile fabrics and plastic films. White inorganic

pigments are also applied to provide opacity to synthetic fibres and plastics

produced by moulding and extrusion processes [11].

2.4 Binder system

Since pigments have no affinity for the fibres/fabric, the polymeric binder plays an

important role in linking the pigment and fabric and influences the colour durability,

including wet, dry and washing fastness [18]. Pigment binders are polymer latexes

which are formed by selecting monomers which contribute specific properties to the

binder. The process, combining monomers together to form polymer, is called

polymerisation, and in pigment colouration it is called emulsion polymerisation [19].

There are several advantages offered by the emulsion polymerisation process, but

most of the polymer advantageous properties are due to the high molecular weight

improving the physical properties. An aqueous dispersion is the most common form

of binder, in which 40%-45% binder solids are incorporated into water [1, 7, 20].

The droplets are similar sizes with those of the pigment particles, at most, less than

0.5 microns in diameter.

After evaporation of the solvent or other dispersion medium on heating, the particles

coalesce together to form a thin coherent coating, the film, which is several micron

thick, enclosing the pigment particles and adhering to the fibre [7]. The binder film


56

is a three-dimensional structure with the first and second dimensions being more

important than the third [1]. A binder must be compatible with the pigment

application and have other characteristics to improve the colouring impact of the

pigment [21]. A “good” binder typically has following properties:

The binder film is tenacious and elastic;

The binder film should be colourless and transparent in order to present the

pigment hue efficiently;

The binder film should exhibit good flexing resistance, abrasion resistance,

chemical resistance and light resistance.

Binders are usually produced from synthetic polymers, but also natural wood resin,

wax, linseed or safflower oils and chitosan have been examined in order to

incorporate their biodegradability [22]. Following industrial trials chitosan has been

identified as the best choice and such ecologically friendly binders are already used

in production [22].

2.5 Softeners

Aside from appearance, the handle of the textile is also a very important quality

indicator for most manufacturers and customers. Accordingly, almost all apparel and

home furnishing textiles are treated with softeners [23]. During laundering there is

strong mechanical agitation giving rise to fabric deformation and harshening of the

fabric handle. Subsequent drying, particularly line drying sets this effect imparting

an uncomfortable hand. Similarly prior to domestic processing the binder utilised in

pigment printing and dyeing produces a stiffening of the fabric handle. In contrast

the use of low solubility alkali soaps in scouring processes resulted in incomplete

removal of the soap and the residual soap on the fibre imparted a softer feel and

generally a better handle to the fabric [24].


57

A softener can be defined as “an auxiliary that imparts a pleasant handle and

smoothness when applied to textiles” [25, 26]. The softening effect is not only

evident in the handle property but also produces easier ironing, sewing and other

operations in which friction affects the performance. Most softeners are composed

of molecules with both a hydrophobic and hydrophilic constituent. According to

their ionic nature and structures, softeners can be subdivided into three types:

cationic, anionic or non-ionic [27].

As the most important softeners, cationic softeners are most widely used and

achieve the best results. Their cationic character is typically based on a positive

charged quaternary ammonium ion [24, 28]. Since most textile materials possess a

negative charge when immersed in water, cationic softeners are electrostatically

attracted to the fabric surface. They usually are applied by exhaustion methods.

However, there are some problems due to the positive charge, such as when they

react with anionic dyes creating problems such as shade changes and colour

bleeding. Because of their interaction with anionic detergents, their wash fastness is

usually limited but can be improved by incorporating reactive functionalities into the

softener that can react with the fibre [24].

Anionic softeners with a negative charge are composed of hydrophobes linked to

anionic groups as carboxylates, carboxymethyls, sulphates, sulphonates or even

phosphates [28]. Anionic surfactants can be used as softening agents, wetting agents

and detergents, because they give a good handle after a domestic wash. They are

generally applied by padding due to the low affinity for most of the fibres.

Non-ionic softeners contain the similar hydrophobe chains to the anionic type, but

the hydrophobes are ethoxylated, R-(OCH2CH2)x-OH. Non-ionic softeners are


58

applied by padding method because they have little affinity for the textile fibres and

can be co-applied with other ionic or non-ionic textile chemicals/auxiliaries.

In addition, silicone softeners are based on a siloxane backbone, Si-O. They can be

emulsified in water and then pad applied onto the fabric, since they do not have a

high affinity for the fibre. Three types of silicones can be distinguished.

Polydimethylsiloxanes, which offer flexibility due to the elastic polymer backbone,

lacks affinity for the fabric and they tend to be removed during washing. They are

held to the substrate through weak intermolecular forces. In order to get better wash

fastness polydimethylsiloxanes with reactive groups were developed which can react

as a crosslinking agent and so gives elastomeric structures between the siloxane

chains. A further development of the siloxanes are the amino-functional type silicone

softeners which exhibit a slight cationic character due the NH group, especially in

acidic media, and exhibit higher affinity for the negatively charged fibre. However,

the primary and secondary amino groups can introduce yellowing during subsequent

processing and teriary derivatives need to be used [24].

2.6 Other Auxiliaries

Crosslinking agents

A crosslinker may also be incorporated into the binder formulation in order to

enhance the fastness of coloured fabrics [29]. However, an excess of the crosslinker

may result in an unacceptably stiff handle. The crosslinking process is typically a

condensation reaction involving formaldehyde-based derivatives which eliminate

water, and are required when the binder has no self-crosslinking groups, just reactive

groups for bonding to the substrate. When crosslinkers are applied to cellulosic

fibres, chemical bonds will also be formed between the binder and fabrics. A

crosslinker should be selected on the basis of optimised temperature, pH and curing

time. In addition the reactivity of the crosslinker needs to be considered in order to


59

ensure premature reaction does not occur in the print/dye paste leading to damage in

the subsequent film formed by the binder particles, or even cause the print paste or

dye solution to gel [7].

Thickeners

In pigment printing it is necessary to incorporate a thickener in order to achieve the

correct viscosity in locating the print motif correctly and preventing diffusion. In

pigment dyeing no such thickener is necessary. The thickener is usually a long chain

acrylic acid-based polymer, although both natural and synthetic thickeners are

commonly used [1]. It increases the viscosity of the paste so as to achieve sharp

well-defined patterning and uniform coverage. Water-soluble thickening agents are

macro-molecular substances, which may form a hard film which will cause a stiff

handle and would reduce the benefit of eliminating the washing off process in

pigment printing. Accordingly some of the polymer binder may provide the

thickening role as well as the pigment binding structure [7, 30].

Wetting agent

A further formulation additive is the wetting agent which expels air from the textile

assembly contained in the aqueous processing bath to lower the fibre/fabric surface

tension. This process increases spreading of the formulation and improves the

uniformity of the surface film. In continuous dyeing, a wetting agent is usually

added to pad liquors [22]. Typically the wetting agents are non-ionic or anionic in

nature although non-ionic surfactants have proved to be best wetting agents in

commercial practise and experimental tests [31].

Hand-modifiers

Hand-modifiers are mostly necessary in pigment colouration. Two types of hand

modifiers can be distinguished. The first chemical hand-modifier is the softeners


60

based on cationic, non-ionic and silicone chemistries [22]. These softeners can lower

surface friction, decrease stiffness and enhance rub fastness [1]. They will make the

binder film more flexible and impart a considerably softer hand [22]. Crosslinking

agents are again chemical in nature and increase fabric stiffness but also improve the

mechanical performance [1]. Handle modification can be achieved by the

mechanical processing (physical processing) as well, such as calendaring, pressing,

raising /cropping and shearing.

2.7 Pigment Application System

2.7.1 Print System

The pigment printing systems can be applied by textile printing machines which are

discussed in 1.6.2. Successful pigment printing systems are based on three equally

significant components: pigment dispersions; binders and crosslinking agents; and

thickeners and auxiliary agents giving the required rheology [1]. The printed sample

is passed through a drying section (usually a hot air oven) and then collected by

folding flat or winding up on a rolling device. The dyed fabric is then sent through

another heat stenter to cure the binder system and achieve polymerization of the

resin. The curing step is often incorporated with the drying step or it can be

combined with a post cure procedure [21]. Environmental impact gains even more

importance when preparing pigment printing paste. In particular toxicological

aspects lead to the development of paste in which hazardous substances are reduced.

Further development has led to biodegradable printing pastes, such as binders made

of chitosan and vegetable natural pigments [22].

2.7.2 Padding System

The padding system is just same as the machines used in continuous dyeing, as

discussed in 1.6.1.4. It essentially consists of a padding process and a drying/fixing


61

process. Only a few ingredients are needed in a conventional pigment pad bath: the

pigment dispersion, the binder dispersion, the anti-migration agent, the wetting

agent and, for some acrylic binders, ammonia. Occasionally some defoamer may be

used.

Most problems occurring in pigment padding can be attributed to just a few reasons:

the fabric preparation, the mix (mixing procedure, agitation/stirring, straining,

incompatibility), the binder (amount, type, buildup), the pigment (amount, type,

buildup), migration on drying (anti-migrant and equipment), the auxiliary chemicals

and the curing conditions [5].

2.7.3 Exhaust Dyeing System

Exhaust dyeing of pigments is commonly used in garment dyeing and is applied by

using a modified commercial laundry machine. The exhaust system application

mainly consists of four stages: fabric cationization, pigment exhaustion, binder

exhaustion and drying [21].

The overall result is very similar to that achieved when pigment padding fabrics, but

the application methodology is substantially different. Since the pre-treatment and

after-treatment chemicals (the particle fixative and the binder) are proprietary, the

precise mechanism of the process is uncertain [5].

2.7.4 Modification of Pigment Application System

2.7.4.1 Cationization

Cellulose fibres, when immersed in water, exhibit a negative zeta potential and most

of the dye classes suitable for cotton are anionic in nature. Accordingly there is

electrostatic repulsion between cellulose fibres and dye molecules, which results in


62

low colour yield [32]. Pre-treatment with a cationic fixing agent should improve the

colour strength and fastness due to the changed charge. Chemically cationized

cotton is usually produced by etherification cotton with a tertiary amino or more

often quaternary ammonium cationizing reagents. They can be reacted with cellulose

fibres under a variety of application conditions, such as exhaust, pad-batch,

pad-bake, pad-steam, jig-exhaust, jet-exhaust, etc. [33].

2.7.4.2 Plasma Treatment

Conventional wet pre-treatment processes of textiles are usually energy consuming

processes. Plasma modification of textiles minimises water, chemicals, and electrical

energy. Ecological and economical constrictions which are imposed on the textile

industry, to an increasing extent, encourage the development of environmentally

friendly and economic finishing processes. Large quantities of savings are achievable

since the plasma process does not produce large volumes of waste, effluent or toxic

byproducts [34].

So far, the required surface modification of the fibre is mainly achieved by wet

chemical processes. An appropriate option to conventional techniques is through the

pre-treatment of textile fibres with low temperature glow discharge plasma in air

[34]. The plasma treatment of textiles is attractive because that it is a clean, dry

technology, which dispenses with water or an organic solvent as a processing

medium. In some cases, plasma treatments can impart properties to textiles which

are otherwise unobtainable through wet processes. Plasma treatments of textiles

modify their surface character without affecting their bulk properties. The depth of

the surface treatment is <100nm. The topography of the textile surface is modified,

and its chemical properties may also be altered [27]. Improvements to the textile’s

properties may include increasing fibre wettability, fibre failure stress and strain,

improving shrink resistance and reducing fabric surface resistivity [35, 36]. This


63

depends on whether greater chemical affinity or inertness has been conferred on the

textile surfaces. Other properties which could be improved are adhesion,

biocompatibility, resistance to wear and tear, rate and depth of dyeing, cleaning of

fibre surfaces, and desizing [27].

The oxidation of the surface of a material, the generation of radicals, and the etching

of the surface are the general reactions which can be achieved by plasma. When

special monomer gases are used, a plasma-induced deposition polymerization may

occur. For the treatment of textiles, this action means that hydrophilization and

hydrophobization may be accomplished; furthermore, both the surface chemistry and

the surface topography could be influenced to result in improved adhesion or

repellency properties as well as the introduction of functional groups to the surface.

Plasma treatment has to be controlled carefully to minimise the damaging action of

the plasma onto the substrate [37].

Two main approaches of plasma treatments applied to the surface modification of

textiles are depositing or non-depositing plasmas. With the depositing plasmas, the

plasma is generally applied by using saturated and unsaturated gases such as fluoro-

and hydro-carbons or vapours (monomers) such as acetone, methanol, allylamine and

acrylic acid. Several reactive etching (Ar, He, O2, N2, F2) or non-polymerisable gases

(H2O, NH3) are utilised in the non-depositing plasmas [38].

Many studies on plasma surface modification of cotton have been undertaken, using

glow-discharge technology at low pressure as well as barrier discharge and corona

treatments at atmospheric pressure. In both conditions, active particles such as

radicals, ions, electrons and photons are generated. When they are under reduced

pressure, these particles have a much larger free path length as compared with the

process at atmospheric pressure. Subsequently, the treatment at atmospheric pressure


64

generally occurs in a narrow slit, while the treatment at low pressure is performed in a

reactor with a volume adapted to the size of the samples [39, 40].

Research on air and oxygen plasma treatments of cotton fibres have been studied for

many years, with parameters such as discharge power, treatment time and nature and

flow rate of the gas investigated. The chemical effect of the treatments on the cotton

fibres was evaluated via a range of different methods. In many experiments, it was

found that the plasma treatments resulted in surface erosion of the cotton fibres, which

caused a weight loss, accompanied by an increase in carboxyl group and carbonyl

group contents. The growth in carboxyl group concentration led to a more wettable

fibre and the increase of the rate of fabric vertical wicking. It was also shown that the

fabric yellowness is greater with the increase of treatment time. Several studies have

proved that exposure of the cotton fibres to fluorinated gas plasmas leads to a

decrease of water absorption or wettability. Fluorocarbon gas plasmas can modify

surface properties by means of either surface treatment or polymerisation and

deposition of a thin film [39, 41, 42].

2.7.4.3 Fluorocarbon Treatment of dyed fabrics

Fluorochemicals are defined as a man-made, organic fluorine containing compounds

in which most hydrogen atoms are replaced with fluorine. The first syntheses of

fluorochemicals, which are extremely chemically reactive, were conducted in 1886

by Moisson, who harnessed the most electronegative element in nature. The

electrons in fluorine atom are held close to the nucleus with the chemical bond

length between fluorine and carbon being relatively short, which causes the

chemical structure of fluorocarbons to be very compact. Therefore, in perfluorinated

carbon systems, the small fluorine atoms will cover and impart a shielding action to

the carbon-carbon bond [37].


65

The shielding action has an immense impact on the unique properties of

fluorocarbons and especially of perfluorinated carbon systems. Fluorochemical

products offer some advantageous properties, such as high thermal stability, high

chemical stability, insolubility, and extremely low surface tension. Hence, the use of

fluorochemicals is not limited only to the applications of textile materials, but also

spreads to many other diverse fields. They offer great benefit as a protective agent

against water, stain, and soil for leather, carpet, and paper [37].

A variety of fluorocarbon compounds and polymers can be used to achieve water as

well as oil and stain repellent effects on textiles. If only water repellency is required,

fluorocarbon chain lengths as short as two are adequate [14]. The repellency of

fluorocarbon finishes depends on the structures of the fluorocarbon section, the

non-fluororinated section of the molecule, the orientation of the fluorocarbon tail,

the distribution and the amount of the fluorocarbon moiety on fibres, and the

composition and geometry of the fabric [43].

The fluorochemicals are normally applied by standard finishing processes and

application and must be uniformly distributed so that they penetrate well into the

fabrics. They are applicable both as emulsion and solvent-based solutions. The most

widely used emulsions for fabrics and carpets are of the cationic type, while solvent

solutions are less common. Chemical additives, such as softeners, builders, flame

retardants, or chemical agents for static and bacteria control, could be added in

fabric treating processes. The co-application of these chemicals may have some

influence on final performance properties of the fluorochemical. One typical

example is that there should be no silicones on fabrics or carpets prior to the

fluorochemical treatment because traces of silicone can eliminate the oil repellent

characteristics of the treated fabrics. Silicones can dissolve in oil and reduce the

surface tension of treated fabrics, therefore allowing the oil to adhere to the fabric


66

[37].

There are three methods to treat the fabric by using fluorochemical products:

conventional padding, spraying, and foam application. Before the fluorochemical

treatment, it is necessary to ensure that the fabric is clean and its pH range is 5-7.

Every application method has the same post-processes involving drying and heat

curing operations. All aqueous fluorochemical-based finishes are required to be

oriented correctly in order to form an efficient repellent surface and produce the

bonding of chemical agents on fabrics. The drying process should be immediately

followed after chemical treating by exposing the treated samples to an elevated

temperature and typical drying machines are the forced-air oven type. Curing is

usually performed at 150-190℃, for a period of 2-10 minutes [37].

There are many diverse applications for fluorocarbons due to their versatility.

Because of their outstanding chemical and thermal stability, they can be used as

durable lubricants, corrosion protective coatings for metals, non-flammable plastics,

and fluorine elastomers in the rubber industry and as heat transfer fluids in

refrigeration technology. As a benefit of their non-miscibility, fluorocarbons are

treated as substitution products, and as protective agents against water, oil and soil in

the paper, leather and textile industries. Due to their effective wetting capacity, they

can be applied as fire fighting agents and wetting agents in electro-plating,

electronics and textile industries [44, 45].

2.8 Advantages and Disadvantages of Pigment Colouration

The advantages are:

Pigment colouration is the simplest colouring process as it just consists of

printing/dyeing, drying and fixation. Therefore it is a very economical process,

due to the elimination of all wet after-treatments;


67

The pigment technique can be applied to most substrates, including glass fibre,

imitation synthetic leather and PVC, at light to medium depth;

The spectral range of pigments is extensive, and the colours are bright;

Pigment printing presents the fewest problems for the printer in printing various

fabric blends;

Some special colouration effects can only be achieved using pigments. Also

pigment colouration can greatly decrease the influence of background colour,

such as printing a white pattern on deep shade fabric;

Good light fastness and colour fastness properties can be achieved with the

appropriate print/dyeing formulation;

In the colouration process, pigmentation offers lower labour and equipment

demands while keeping high production reliability;

If pigments are over-printed, the lower layer has almost no effect and the top

layer determines the colour [1, 5].

The disadvantages are:

The application of chemicals, like binders and crosslinkers can cause increased

stiffness and present handle issues;

The colour fastness, especially the wet rub fastness is poor. For medium or deep

shade pigment coloured fabric, which is made from polyester, wool or acrylic

fibres, the degree of colour fastness is ideally only suitable for products that will

not be subjected to a great quality of wear;

Although pigmented samples resist a certain degree of dry cleaning, the

problem of fading after cleaning is still present [1, 5].

2.9 Aims and Objectives of Research

The current research work was undertaken keeping in mind the growing interest in

environmentally friendly textile colouration. As the simplest colouring process


68

pigment colouration just consists of printing/dyeing, drying and fixation. Therefore it

is a very economical and environmentally friendly process, due to the elimination of

all wet after-treatments. There have been many studies in pigment printing area while

the use of pigment dyeing becomes increasingly popular recently due to the concern

of environmental and energy problems. This study aimed at modifying the pigment

dyeing system with a view to improving fastness, in particular improving the wet rub

fastness.

Chapter three details the methodology and standards that were followed in undertaking

the processing research and the subsequent characterisation. Chapter four discusses the

performance of Matrix OSD pigment dyeing system and the standard dyeing system

for this study was chosen. Chapter five deals with the cotton fabric surface

modification and the incorporation of crosslinkers into the binder formulation. The

cationization reagent and ultraviolet/ozone were pretreated on cotton fabrics to

improve the dyeability. Chapter six describes the fluorocarbon treatment in the

pigment dyeing system including plasma polymerized fluorocarbon treatment.

Chapter seven discussed the effects of plasma polymerisation treatments before and

after pigment dyeing. Scanning Electron Microscopy (SEM) analysis was used to

study the changes in the surface morphology of the pigment dyed cotton fibres,

especially for samples before and after rubbing. In addition X-ray Photoelectron

Spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectrometry

(ToF-SIMS) analysis allowed the surface chemistry of the pigment dyed cotton

fabrics to be probed in Chapter eight.

2.10 References

1. Miles, L. W. C, Textile Printing. Rev. 2nd edn, 2003, Bradford: Society of

Dyers and Colourists. x, p.339.


69

2. Kramrisch, B., Pigment Printing and Dyeing of Cotton. American Dyestuff

Reporter, 1986, 75(2): p.13.

3. Humphries, A., Muff, J. R., and Seddon, R., Aqueous System for Pigment

Printing. Colourage, 1985. 32(5): p.15-27.

4. Kass, M., Application of Pigment to Textiles. J. Soc. Dyers Col, 1958.

5. Aspland, J. R., Textile Dyeing and Coloration, 1997, Triangle Park, N.C.:

American Association of Textile Chemists and Colorists. p.410.

6. American Association of Textile Chemists and Colorists. Committee RA80

Printing Technology., Pigment printing handbook, 1995, Research Triangle

Park, N.C.: Committee RA-80 Printing Technology, American Association of

Textile Chemists and Colorists, iii, p.151.

7. Schwindt, W., and Faulhaber, G., The Development of Pigment Printing

Over the Last 50 Years. Review of Progress in Coloration and Related Topics,

1984, 14(1): p.166-175.

8. Printing of Pigments and Special Effects. Cotton Incorporated Technical

Bulletin, 2007, ISP(1017): p.1-14.

9. Denton, M. J., and Daniels, P. N., Textile Terms and Definitions. 11th edn.

2002, Manchester, UK: Textile Institute. ix, p.407.

10. Patton, T. C., Pigment Handbook, 1973, New York,: Wiley.

11. Shore, J., Colorants. 2nd edn. 2002, Bradford: Society of Dyers and

Colourists. ix, p.469.

12. Zollinger, H., Color Chemistry: Syntheses, Properties, and Applications of

Organic Dyes and Pigments. 2nd rev. edn. 1991, Weinheim ; Cambridge:

VCH. xvi, p.496.

13. Christie, R. M., Mather, R. R., and Wardman, R. H., The Chemistry of

Colour Application, 2000, Oxford: Blackwell Science. viii, p.288.

14. Vigo, T. L., Textile Processing and Properties: Preparation, Dyeing,



70

p.479.

15. Hao, Z. M. and Iqbal, A., Some Aspects of Organic Pigments. Chemical

Society Reviews, 1997. 26(3): p.203-213.

16. Smith, F. M., An Introduction to Organic Pigments. Journal of the Society of

Dyers and Colourists, 1962, 78(5): p.222-231.

17. Schwarz, S. and Endriss, H., Inorganic Colour Pigments and Effect Pigments

Technical and Environmental Aspects. Review of Progress in Coloration and

Related Topics, 1995, 25(1): p.6-17.

18. Whistenant, J., Pigments in Textile Printing. Pigment Printing Handbook,

1995, p.45.

19. Hammonds, A. G., Introduction to Binders. Pigment Printing Handbook,

1995, p.57.

20. Patel, D. C., Synthetic Binders for Pigment Printing. Textile Printing 1997.

21. Binders for Textile Applications. Cotton Incorporated Technical Bulletin,

2004, ISP(1008): p.1-16.

22. Lacasse, K. and Baumann, W., Textile Chemicals : Environmental Data and

Facts, 2004, Berlin ; London: Springer. xxvi, p.1180.

23. Schindler, W. D. and Hauser, P. J., Chemical finishing of textiles, Cambridge:

Woodhead in association with The Textile Institute ; Boca Raton. x, p.213.

24. Karypidis, M. I., Effect of Softening Agents on the Wear of Textiles, 2000,

PhD Thesis, Manchester: UMIST.

25. Arunyadej, S., Investigation into the Performance of A Fluorocarbon Finish

on Cotton Fabric, 1997, MSc Thesis, UMIST.

26. Anilin, B., Manual: Textile Finishing, 1973, Ludwigshafen: BASF AG.

27. Wei, Q., Surface Modification of Textiles, 2009, Cambridge: Woodhead Pub.

xx, p.337.

28. Shore, J., Colorants and Auxiliaries, Vol 2., 2nd edn. Society of Dyers and

Colourists.


71

29. Thompson, D., Pigment Printing Auxiliaries. Pigment Printing Handbook,

1995, p.97.

30. Schwindt, W., New Thickening Agents and New Possibilities for Pigment

Printing. Textilveredlung, 1969, 4(9): p.698.

31. Nettles, J. E., Handbook of Chemical Specialties: Textile Fiber Processing,

Preparation, and Bleaching, 1983, New York: Wiley. xviii, p.467.

32. Fang, K. J., Pigment Dyeing of Polyamide-Epichlorohydrin Cationized

Cotton Fabrics. Journal of Applied Polymer Science, 2010, 118(5):

p.2736-2742.

33. Wang, L. L., Preparation of Cationic Cotton with Two-bath Pad-bake Process

and Its Application in Salt-free Dyeing. Carbohydrate Polymers, 2009, 78(3):

p.602-608.

34. Karmakar, S. R., Chemical Technology in the Pre-treatment Processes of

Textiles, 1999, Amsterdam.

35. Cook, J. G., Handbook of Textile Fibres: By J. Gordon Cook, 1968: Merrow

Publishing Company.

36. McIntyre, J., Synthetic Fibres: Nylon, Polyester, Acrylic, Polyolefin, 2005,

CRC Press.

37. Arunyadej, S., Investigation into the Performance of A Flurocarbon Finish on

Cotton Fabric, 1997, MSc Thesis, Manchester: UMIST.

38. Drumright, R. E., Gruber, P. R., and D. E. Henton, Polylactic Acid

Technology. Advanced Materials, 2000, 12(23): p.1841-1846.

39. Shishoo, R., Plasma Technologies for Textiles, 2007, Cambridge: Woodhead

Pub.

40. Hua, Z., Mechanisms of Oxygen- and Argon-RF-plasma-induced Surface

Chemistry of Cellulose. Plasmas and Polymers, 1997, 2(3): p.199-224.

41. Özdogan, E., A New Approach for Dyeability of Cotton Fabrics by Different

Plasma Polymerisation Methods. Coloration Technology, 2002, 118(3):


72

p.100-103.

42. Malek, R. M. A. and Holme, I., The Effect of Plasma Treatment on Some

Properties of Cotton. Iranian Polymer Journal, 2003, 12(4): p.271-280.

43. Lewin, M. E. and Sello, S. B., Handbook of Fiber Science and Technology,

1984, New York: M. Dekker.

44. Grayson, M. E. and Eckroth, D. E., Encyclopedia of Chemical Technology,

Index to Volumes 1-24 and Supplement. 3rd edn . 1984, John Wiley & Sons.

45. Shekarriz, S., An Investigation into the Modification of Cotton Fibres to

Improve Crease Resist and Repellency Properties, 1999, PhD Thesis,

UMIST.

Chapter 3 Instrumental Techniques

73


3.1 Introduction

This chapter discusses the methodology and standards which were followed in

undertaking the processing research and the subsequent characterisation. In this study

dyed fabrics were analysed in terms of colour fastness, colour strength, “handle”,

surface analysis (X-ray Photoelectron Spectroscopy (XPS) and Time-of-Flight

Secondary Ion Mass Spectrometry (ToF-SIMS)) and appearance (Scanning Electron

Microscopy (SEM). There are various standards available for the testing of textiles, such

as ISO (International Standards Organization), AATCC (American Association of

Textile Chemists and Colorists) and B.S. (British Standards).

3.2 Physical Testing

3.2.1 Colour fastness

The definition of colour fastness, proposed by the American Association of Textile

Chemists and Colourists, is as follows: ‘The resistance of a material to change in

any of its colour characteristic, to transfer its colourants to adjacent materials, or

both, as a result of the exposure of the material to any environment that might be

encountered during the processing, testing, storage, or use of the material’ [1].

Colour changes of the test specimen and staining of undyed adjacent fabrics are two

aspects of the colour fastness assessment. There are two standard grey scales used to

assess change, colour change grey scales and the degree of cross-staining grey scales

[2].


74

3.2.1.1 Rub fastness

In this study, Rub fastness of the cotton fabric was performed in accordance with

ISO 105-X16: 2002 standard. The AATCC crockmeter, Figure 3.1, was used as the

rubbing fastness tester. Prior to testing, the crock squares and specimens were

conditioned for at least 24 hours in an atmosphere of 21±1℃ and 65±2% RH. The

specimen was then placed on the base of the crockmeter resting flat and the crock

square covered the end of the finger as presented in Figure 3.1. For the wet rub

fastness, the crock squares need to be wetted at a wet pick-up about 65±5%. The

finger was lowered onto the test specimen and moved 10 complete turns. The white

crock squares were evaluated in comparison to the Grey Scale for Staining, shown in

Figure 3.2. The dry and wet rub fastness was rated at 9 levels: 5, 4/5, 4, 3/4, 3, 2/3, 2,

1/2, 1 [3].

Figure 3.1 AATCC crockmeter


75

Figure 3.2 Grey scale assessment for staining

3.2.1.2 Wash fastness

The fastness to laundering of pigment dyed fabrics was determined according to the

ISO 105-C06: 2002 test method. A fabric sample, 100±2mm x 40±2mm, was stapled

to a piece of the same size multifibre adjacent fabric.

The wash liquor was prepared by dissolving 4 g/L of SDC ECE detergent (phosphate

based) and 1 g/L sodium perborate tetrahydrate in 1 litre distilled water and stirred at

60°C. There was 50mls of detergent solution and 25 steel balls added in each steel

container. The Roaches Washtec P machine was set at 60°C for 30 minutes. The

samples were then removed, rinsed in distilled water and air-dried. The change in

colour of the specimen and the staining of the adjacent fabric were assessed using the

Grey Scale for Staining and the Grey Scale for Colour Changing, Figure 3.3. The

wash fastness was rated at 9 levels similar to the rub fastness testing [4].


76

Figure 3.3 Grey scale for assessing colour change

3.2.2 Colour Strength

The strength of colourant can be measured in terms of the Kubelka-Munk (K/S)

value which has been derived from the Kubelka-Munk function (R) [5].

K/Sλ =(1 − R∞)

2

2R∞

Where R∞ = reflectance of light of a particular wavelength from a sample of infinite

thickness. Colour strength by a single wavelength method was measured at a

specified wavelength (λ) of maximum absorption using the above equation where K

is the absorption coefficient and S is scattering coefficient. Reflection of the samples

was measured from 400-700nm at intervals of 20nm [5]. In this study by measuring

reflectance (R) with a DataColor 500i spectrophotometer, K/S can be determined.

The samples (folded four times) were held on the spectrophotometer measuring port.

The spectrophotometer was calibrated under white, black and green standards with

the following settings: USVP, 10˚Standard Observer, UV/Specular excluded.


77

3.2.3 Martindale Abrasion Test

The Martindale abrasion test was performed according to BS 569091:1991. The

standard crossbred worsted abradant material used in the test was replaced at the

beginning of each new test. The samples to be tested were conditioned in a standard

atmosphere, with a relative humidity of 65±2% R.H. and a temperature of 20±2℃,

for at least 24 hours before testing. For each sample, four circular pieces were cut

with a 38 mm diameter using a press cutter. Each individual piece was mounted in a

sample holder on the abrasion machine with a circular 38 mm diameter piece of

polyurethane foam and placed behind the sample as backing. Each of the sample

holders was fastened on the moving plate under a load of 12 kPa and fabrics were

abraded under a cyclic planar motion. Samples were examined at suitable intervals,

shown in Table 3.1, using a low power stereomicroscope to ascertain whether two

yarns were broken while sample pieces were still on sample holders. The mean

values of the rubs for the four pieces of each fabric were not recorded until the

second yarn breakdown [6].

Table 3.1 Test intervals for abrasion testing

Test series

Number of rubs (N) at

which specimen

breakdown occurs

Test interval

(rubs)

A N ≤ 5000 Every 1000

B 5000 < N ≤ 20000 Every 2000

C 20000 < N ≤ 40000 Every 5000

D N > 40000 Every 10000

3.2.4 KES-F System

Fabric handle is a subjective judgement for each person according to touch and feel.

There are descriptive adjectives and hand feeling terms, such as smooth, rough, stiff,


78

soft and so on, used to describe this assessment [2, 7]. So, it is generally agreed that

the subjective assessment of handle is the transmission of information from finger

stimuli to human perception. Before the Kawabata system, fabric handle was

evaluated by skilled experts who had training to judge the quality with their hands,

but with the average consumer the results vary from person to person and

predictability and sensitivity were accordingly more variable.

The Kawabata Evaluation System (KES) measures the fabric’s mechanical and

surface properties at low load levels typical of normal handling and end-user

applications. The system has been used to predict performance in garment

manufacture and to develop optimal finishing routines in order to maximise the

quality of the final garment fabric.

In this research, the 20 x 20 cm fabrics were conditioned for 24 hours at 20ºC and 65%

R.H. prior to testing. The selected KES-F shear and bending mechanical property

values presented were the average of five measurements. However the full set of

KES parameters that can be measured are listed in Table 3.2.


79

Table 3.2 Parameters measured in the Kawabata Evaluation System

Parameter Symbol Units

Tensile Properties

Extensibility EM %

Linearity of Load-Extension Curve LT -

Tensile Energy WT g.cm/cm2

Tensile Resilience RT %

Bending Properties

Bending Stiffness B g.cm2/cm

Bending Hysteresis 2HB g.cm/cm

Shear Properties

Shear Stiffness G g/cm.deg

Shear Hysteresis at 0.5o 2HG g/cm

Shear Hysteresis at 5o 2HG5 g/cm

Surface Properties

Coefficient of Friction MIU -

Mean Variation of MIU MMD -

Geometrical Roughness SMD μm

Compression Properties

Linearity of Pressure-Thickness curve LC -

Compression Energy WC g.cm/cm2

Compression Resilience RC %

Miscellaneous

Thickness T mm

Weight W mg/cm2


80

Bending stiffness (B) relates to the ability of a fabric to be distorted by bending. It is

generally a function of fabric weight and thickness but can also reflect the effect of

chemical processing and/or finishing routines. Bending stiffness is particularly

important in the tailoring area for lightweight fabrics. It is difficult to sew a very

supple fabric which means that its bending stiffness is low, whereas a firm fabric can

be more manageable in sewing and offer a flat seam. However, lower bending

stiffness provides a higher total hand value and better flexibility/drapability.

Shear properties in association with bending stiffness can provide an indication of

the fabric drapability. Assessment of this property gives a measure of the resistance

to rotating movement of warp and weft yarns within a fabric. Certain chemical

treatments like the application of fabric softeners can moderate the fabric shear

stiffness property by lubricating the yarns and reducing the inter-yarn friction. They

are measured with a maximum shear angle of ±8˚. Lower values of shear stiffness

(G) would cause more difficulty in laying and handling because of the fabric

distortion and garment appearance would be worse. Shear hysteresis at 5˚ shear

angle (2HG5) is the measurement of energy loss during shear deformation. Mostly

this energy loss is caused by inter-yarn friction at crossing points. Higher shear

hysteresis indicates that more recovery forces would be required to overcome fabric

internal friction. Smaller 2HG5 values impart comfort, softness, drape, and garment

appearance. However, too low 2HG5 values could cause a reduction in fabric

sewability due to fabric high elastic behaviour in shear distortion [8].

3.2.5 Oil and Water Repellency Measurements

Several test methods are available to measure fabric wetting resistance to selected

liquids. In this study, the 3M oil and water repellency tests were chosen because of

the portability and simplicity of the instrumentation and test procedure. It is

applicable to any fabrics which are with or without a liquid resistant or liquid


81

repellent treatment [9].

In 3M test, the degree of water repellency ranges from W to 10W, while the degree

of oil repellency ranges from 1 to 8. If totally without repellency, it is marked

‘failed’. The liquids used in the water repellency test include water, water/isopropyl

alcohol mixtures and isopropyl alcohol. In oil repellency testing, the test liquids are

liquid-phase paraffin, n-hexadecane, n-dodecane, n-decane, n-octane, and n-heptane.

Different test liquids offer varying degrees of repellency and associated surface

tension as shown in Tables 3.3 and 3.4 [9].

Table 3.3 Range of test liquids with decreasing surface tension for the oil-repellency

test [10]

Oil-Repellency Test Liquid Surface Tension

(mNm-1

at 25℃)

1 Nujol oil 31.2

2 65/35 nujol/n-hexadecane 28.7

3 n-hexadecane 27.1

4 n-tetradecane 26.1

5 n-dodecane 25.1

6 n-decane 23.5

7 n-octane 21.3

8 n-heptane 19.6

Table 3.4 Range of test liquids employed with decreasing surface tension [11]

Test Liquid Composition of Test Liquid %

W 100 Water

W1 90/10 Water/Isopropyl Alcohol









W10 100 Isopropyl Alcohol


82

According to the 3M test procedure, a drop of test liquids is placed on several

locations of the fabric surface. Then the observations of wetting and contact angle

are made. The degree of water and oil repellency is determined, after the observation

period of 10 seconds for water repellency and 30 seconds for oil repellency, by

recording the highest numbered test liquid which does not wet the fabric surface [6].

3.3 Analytical Methods

3.3.1 Scanning Electron Microscopy (SEM)

The scanning electron microscope images the specimen’s surface by focusing an

electron beam onto the materials surface and collecting the reflected electrons from

the surface to form an image. It can achieve high magnification with excellent depth

of focus coupled to a simple sample preparation operation. Since most textile fibres

are usually non-conductive they have to be coated with a thin conducting film to

reduce the probability of ‘charging’ effect. Normally a 2 – 20nm coating should be

carefully applied, since an extremely thick coating may hide surface details [12].

Scanning Electron Microscopy is based on the interaction between a beam of

electrons and the solid surface onto which it collides. Figure 3.4 shows a simplified

schematic diagram of an SEM [13].

The electron gun is a thin, pointed filament of wire, which is electrically heated and

then emits electrons from its tip which are collected and focused. The energy and

direction of these electrons are controlled by the applied voltage between the filament

(forming the cathode) and an annular metal plate (the anode) which is placed under

the filament [13]. When the high-energy electron beam impinges the surface of fabrics,

a range of interactions occur leading to particle or radiation emissions. The image


83

detector collects the backscattered and low-energy (secondary) electrons in forming

the image [12].

Figure 3.4 Schematic of a typical SEM [13]

In this study, a Hitachi S-3000N Scanning Electron Microscope was used and after

attaching the samples on the sample holder, a gold coating was applied using a Gold

Sputter-Etch unit. The SEM analysis was performed with working voltage 5kV, a

working distance around 9.5mm and a magnification of 2000 times.

3.3.2 X-ray Photoelectron Spectroscopy (XPS)

Of all the surface chemical analysis techniques, X-ray photoelectron spectroscopy

(XPS) is the most widely used characterization tool. XPS can be also called Electron

Spectroscopy for Chemical Analysis (ESCA) [14]. The breadth of obtained

information and its flexibility in examining a wide range of materials are the reasons

why XPS is popular as a surface analysis technique [15]. The XPS technique

involves bombarding the surface with X-rays and determining the binding energy


84

(BE) of the emitted photoelectrons ejected from the outer depth 3-5nm of the tested

sample. The photoelectron BE value allows the emitting atom to be identified and its

oxidation state and chemical environment established. Quantitative information

about the elements can be also provided by XPS technique.

XP spectra were obtained from a Kratos Axis spectrometer. The textile samples were

attached on the spectrometer probe with double sided adhesive tape and analysed

with Al Kα radiation (1486.6eV). The spectrometer pressure was 4x10-8

torr. Wide

survey spectra were recorded at a pass energy of 100eV in order to determine the

surface chemical composition. High resolution spectra were recorded with a pass

energy of 20eV and all BE values were calculated in relation to the C(1s)

photoelectron peak at 285.0eV [6]. Charge compensation for the samples was

achieved using a 4–7eV beam at a flood current of ~0.1 mA, with an electrically

ground 90% transmission nickel mesh screen. All samples were analyzed in

duplicate and the data was analyzed using CASA XPS software.

The XPS spectrum contains peaks, which can be associated with the various

elements (except H and He) present in the outer 3-5 nm of the tested fabric. The

amount of each element is related to the area under these spectral peaks. Therefore,

the atomic compositions of each element detected can be determined by measuring

the peak areas and correcting using the photo-ionisation cross-section values [16].

3.3.3 Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS)

ToF-SIMS is a technique which can analyse surface chemistry with great precision

and sensitivity and is particularly useful for characterising organic species at

surfaces. In operation, the surface of a sample is bombarded by energetic particles,

usually ions, and the masses of the sputtered secondary ions from the surface are

characterised accordingly [17]. Both molecular and elemental details can be


85

provided. In addition, ToF-SIMS offers better surface sensitivity for fabric samples

with a sampling depth is approximately 1-2nm, while that of XPS is approximately

3-10nm [18]. The high mass resolution is a characteristic of ToF-SIMS, which

allows accurate mass analysis for clear identification of empirical formulae of

unknown materials.

In this research, pigment dyed, fluorocarbon treated, washed and washed and heat

pressed samples were analysed by CERAM, Stoke, UK. The operation involves

sputtering the sample with a pulsed beam of bismuth primary ions (Bin+ where n =

1-3). Elemental and molecular fragment ions formed at the surface were

mass-analysed and mass spectra were obtained. Positive and negative ion spectra

were acquired from an area of ~500µm x 500µm in the mass range 0-2000.

3.4 References

1. Colorfastness of Cotton Textiles. Cotton Incorporated Technical Bulletin,

2002.

2. Saville, B. P., Physical Testing of Textiles, 1999, Cambridge, England:

Woodhead Publishing.

3. Rivlin, J., The Dyeing of Textile Fibers: Theory and Practice, 1992,

Philadelphia: J. Rivlin. xiii, p.220.

4. British Standards Institution, Textiles. Tests for Colour Fastness. Colour

Fastness to Domestic and Commercial Laundering, 2010, BSI.

5. Tayyebkhan, A., Colour Physics, 1996, Oil and Colour Chemists

Association.


Improve Crease Resist and Repellency Properties, PhD Thesis, 1999,

UMIST.


86

7. Collier, B. J. and Epps, H. H., Textile Testing and Analysis, 1998, Upper

Saddle River, NJ: Prentice Hall. xx, p.374.

8. Dhariwal, J., An Investigation into the Effect of Pigment Printing on Fabric

Handle, 1996, Manchester: UMIST.


Academic & Professional. xiii, p.361.

10. Data, M. T., Test Method - Water Repellency Test II - Water/Alcohol Drop

Test, 1996.

11. Data, M. T., Test Methods - Oil Repellency I, 1996.

12. Greaves, P. H., Saville, B. P., and Royal Microscopical Society (Great

Britain), Microscopy of Textile Fibres. Microscopy Handbooks, 1995,

Oxford: BIOS Scientific in association with the Royal Microscopical Society.

xii, p.92.

13. Love, U. P. G., Scanning Electron Microscopy, in Centre for Electron Optical

Studies, 1999, University of Bath: UK. p.10.

14. Vigo, T. L., Textile Processing and Properties: Preparation, Dyeing,

Finishing, and Performance. Textile science and technology, 1994,

Amsterdam Netherlands ; New York: Elsevier. xvii, p.479.

15. Zeng, F., Investigation into the Colouration of Polypropylene, 2002, PhD

Thesis, UMIST.


Plasma Polymerisation Methods. Coloration Technology, 2002, 118(3):

p.100-103.

17. Vickerman, J. C. and Briggs, D., ToF-SIMS: Surface Analysis by Mass

Spectrometry, 2001, Chichester: IM; Manchester: SurfaceSpectra.

18. Höcker, H., Plasma Treatment of Textile Fibers. Pure and Applied Chemistry,

2002. 74(3): p.423-427.

Chapter 4 Investigation of Basic Binder System

87

Chapter 4 Investigation of Basic Binder

System

4.1 Introduction

As discussed in 2.4, the binder plays an important role as a key element in the

performance of the pigment colouration. It affects colour fastness, fabric handle, and

colour strength [1]. Thus, before providing further insight into pigment colouration,

it is necessary to first elaborate on the binder system. As the earliest textile printing

method, pigment printing is the most important technology which has been applied

for many years. There have been many investigations in this area but with the use of

pigment dyeing becoming increasingly popular recently due to the concern of

environmental and energy problems papers in this area have also appeared [2-7].

Therefore in order to reduce wastage and contribute to cost-effectiveness, pigment

dyeing may become one of the best choices for textile dyeing. The main limitation

of pigment colouration, however, is the relatively poorer colour performance, in

particular the low wet rub fastness and harsher handle [8-10].

This study investigates pigment dyeing and specifically two types of binders, Matrix

OSD and Matrix OSD without softener, manufactured by Beyond Surface

Technologies. Matrix OSD is a formulation containing a silicone-based softener and

binder. Matrix OSD is the only binder used in this research as it is specifically

marketed as offering environmentally beneficial performance. Also Matrix OSD

without softener was assessed due to potential non-compatibility with fluorocarbon

treatments, Chapter 6, and in order to assess the effect of the softener on the binder

properties. According to the supporting company information for Matrix OSD, it can

be used together with most products commonly encountered in high-grade finishing.

Thus it is suitable for the pre- or after-treatment of fabrics.


88

Mercerized and bleached cotton fabric was used in the initial studies and bleached

cotton fabric was used subsequently. Mercerization involves the modification of

cotton yarn or fabric by swelling when immersed in a concentrated aqueous solution

of caustic soda [11, 12]. In theory, the beneficial effects of cotton mercerization

include: increased tensile strength, softness, lustre (if mercerized under tension),

improved affinity for dyes, dyeability of immature fibres and higher water sorption

[11].

4.2 Experimental

4.2.1 Materials

Fabrics 100% bleached, mercerized plain weave cotton fabric, 135g/m2,

was supplied by Phoenix Calico, Stockport.

100% bleached plain woven cotton fabric, 191.5g/m2, was also

supplied by Whaleys, UK.

Pigments Helizarin EE-BBT was supplied by BASF, UK.

Lyosperse red 2BN LIQ and Lyosperse yellow MR LIQ were

supplied by Huntsman, UK.

Neoprint Green-LBS, Black-LBAC and Blue-LBS were supplied

by Beyond Surface Technologies, Switzerland.

Minerprint Blue B was supplied by Quality Colours, UK.

Binders Matrix OSD was supplied by Beyond Surface Technologies,

Switzerland.

Matrix OSD, without softener, was supplied by Beyond Surface

Technologies, Switzerland.

Wetting agent Alcopol 070 was supplied by Huntsman, UK.


89

4.2.2 Dyeing System

Distribution of the pigment over the “wettable” textile during pigment dyeing is first

and foremost a function of the application machine technology. In this study, the

padding system was chosen as the main application system. Normally, pigment

dyeing is performed in several steps, in particular the three stages are: pad bath

preparation; padding; drying and curing [13].

A 2-roll horizontal padder, Werner Mathis HF, was used throughout the study with the

wet pick up controlled by pneumatic pressure transmission at the nip. The pigment

dyeing solution filled the nip through which the fabrics passed during immersion and

subsequent squeezing. The fabric was evenly padded to avoid non-uniformity, with

the padding speed and wet pick up being 2m/minute and 80%, respectively.

The Benz stenter, JT/M 500, was used for thermal treatments of textile materials

throughout the study. It can be used for drying and stabilizing surface materials, fixing

of dyes, and offers the possibility of continuous processes with pre-padding on the

padder. The samples were pinned on the frame evenly and the process of drying

controlled, in case of the migration of pigment solution introducing non-uniformity.

For the pigment dyeing system, the temperature is 110℃ for 3 minutes in the drying

process and 180℃ for 1 minute during the fixation period.

4.2.3 Matrix OSD System

The 100ml stock formulation consisted of 90mls Matrix OSD binder and 10mls

pigment colourant. Five different stock formulations were made containing the red,

yellow, black, blue and green pigments. For each colour, three different

concentrations were prepared contained 10g/L, 50g/L and 100g/L stock formulation,


90

listed in Table 4.1. The cotton fabrics were padded at 80% wet pick up (w.p.u.), then

dried at 110℃ for 3 minutes, and cured 1 minute at 180℃.

Table 4.1 Concentration of stock formulations

Red Yellow Blue

Formulation Conc. g/L 10 50 100 10 50 100 10 50 100

Black Green

Formulation Conc. g/L 10 50 100 10 50 100

4.2.4 Modified Matrix OSD System

Following the preliminary studies in 4.2.3 the Matrix OSD 100ml stock formulation

consisting of 90ml Matrix OSD and 10ml pigment colourant was prepared using the

red, yellow and blue pigments at 10g/L, 100g/L and 150g/L, representing light,

medium and heavy shades, Table 4.2. In the dyeing solution, 1g/L wetting agent was

added to improve the wettability of fabrics. Three different fabrics were treated

using this formulation set, cotton, poly/cotton (55/45) and polyester (PET). They

were padded twice at 80% wet pick up (w.p.u.), then dried at 110℃ for 3 minutes,

and cured 1 minute at 180℃.

Table 4.2 Concentration of stock formulation

Red Yellow Blue

Formulation Conc. g/L 10 100 150 10 100 150 10 100 150

4.2.5 Matrix OSD without Softener

The formulation composition was the same as the modified Matrix OSD system, the

only difference being the use of the binder, which does not contain any silicone

softener. The application process and formulation concentration was exactly the

same as in the modified matrix OSD system.


91

4.3 Results and Discussion

4.3.1 Matrix OSD System

The main indicators of the performance of the binder/colourant system, the rub

fastness, wash fastness, colour strength and fabric handle were tested for the Matrix

OSD system. From the results presented in Table 4.3, it can be seen that the different

pigment colourants in each concentration level show the similar fastness results

except wet rub fastness. It is apparent that wash fastness and dry rub fastness remain

at a high level, whereas wet rub fastness was relatively poorer. Interestingly, the

results of lighter colours are visible better than those of darker coloured fabrics,

indicating wet rub fastness performance was affected by the depth of colour. The

colour strength (Table 4.4) of the dyed fabrics increased with the higher levels of

stock formulation concentration.

Figures 4.1-4.3 show the effect of varying the concentration of formulation applied

to cotton fabric on bending stiffness, shear stiffness and shear hysteresis,

respectively, indicating that the bending stiffness increased as the stock formulation

concentration was raised. The handle properties of the fabric samples with lighter

colours were in general “softer” than those the heavier shades, with the trends for

each colour similar. The bending stiffness of the plain cotton fabric was higher than

the 10g/L dyed samples. This was caused by the “relaxing” aqueous treatment and

the softener in the binder formulation at low application levels reducing the

stiffening action of the binder. The shear stiffness shows the same trend as bending

stiffness although again the increases were relatively small. The shear stiffness of

the untreated cotton was lower than those fabrics with concentrations of 50g/L and

100g/L, but higher than those fabrics treated with 10g/L formulation. Examination

of the shear hysteresis at 5o values indicated variable behaviour with any increases

in interyarn surprisingly small. 2HG5 has been identified as the KES-F parameter


92

most sensitive to fabric softness with any lubrication by softeners of fibre surfaces

being reflected in lower interyarn friction.


fabric on the wet/dry rub fastness

Formulation

Conc. g/L

Rub Fastness Wash Fastness

Dry Wet Colour Change Staining

Yellow

10 4/5 4 5 5

50 5 3 5 5

100 5 3 4/5 5

Red

10 5 4 5 5

50 4/5 3/4 5 5

100 4/5 3 4/5 5

Green

10 4/5 3 4/5 5

50 4/5 2/3 4/5 5

100 4/5 2/3 5 5

Blue

10 4/5 3 4/5 5

50 4 2/3 5 5

100 4 2/3 5 5

Black

10 5 3/4 4/5 5

50 4 2/3 4/5 5

100 4/5 2/3 4/5 5


fabric on the colour strength

Formulation Conc. g/L λmax (nm) (K/S) λmax

Yellow

10 430 0.87

50 440 3.81

100 440 6.31

Red

10 570 0.56

50 570 2.31

100 570 4.4

Green

10 640 0.67

50 640 2.86

100 640 5.35

Blue

10 610 0.88

50 610 3.05

100 610 5.26

Black

10 400 0.95

50 400 2.92

100 400 5.08


93

0 10 20 30 40 50 60 70 80 90 100 110

0.15

0.20

0.25

0.30

0.35

Ben

din

g S

tiff

nes

s (g

.cm

2/c

m)

Formulation Conc. (g/l)

Red

Yellow

Blue

Green

Black


fabric on the KES-F bending stiffness, B

0 10 20 30 40 50 60 70 80 90 100 110

2.0

2.2

2.4

2.6

2.8

3.0

3.2

Sh

ear

Sti

ffn

ess

(g.c

m/d

eg)


Red

Yellow

Blue

Green

Black


fabric on the KES-F shear stiffness, G


94

0 10 20 30 40 50 60 70 80 90 100 110

7

8

9

10

11

Sh

ear

Hy

ster

esis

(g

/cm

)


Red

Yellow

Blue

Green

Black


fabric on the KES-F shear hysteresis at 5o, 2HG5

4.3.2 Modified Matrix OSD System

4.3.2.1 Treatment on Cotton

In subsequent studies a higher concentration of the stock formulation, 150g/L, was

used to achieve a better understanding of the matrix OSD system. A wetting agent

was also added in order to achieve treatment uniformity. Although the concentration

of formulation was increased to a relatively high concentration of 150g/L, it is

shown in Table 4.5 that dry rub fastness and wash fastness were maintained at an

acceptable performance level of 4/5 to 5. The wet rub fastness was relatively poor at

the higher concentration and becomes worse with the increase of depth. The reason

why colour strength was different for the same colour at the same concentration to

the previous dyeing applications was probably due to different pigments were used.


95

From Figures 4.1-4.3, the main trend of each handle property for different colours

was almost the same, so in this section only blue dyed samples are shown as Figures

4.4-4.6. The numerical values are slightly different from those observed in Figure

4.1-4.3, due to the change of cotton fabric quality. However, the main trends were

still observed.

Figure 4.7(a)-(c) show the SEM micrograph images of untreated cotton fabric that

had been dry and wet rubbed, and it is evident that the wet-rubbed damage is more

obvious than in the dry-rubbed materials due to the water swelling the fibre and

increasing its propensity to wet fibrillation and reducing interface adhesion.

Figures 4.8-4.10 illustrate the SEM micrographs of fabrics treated with the modified

Matrix OSD system without pigment. The binder concentrations are 9g/L, 90g/L and

135g/L, which was the same as the binder concentration in the formulation.

Compared with the micrographs of the untreated cotton, it was apparent that there

was polymer binder deposited on the surface of fibres and at the 9g/L binder

concentration application threadlike interfibre bonding was observed. While at

90g/L and 135g/L application levels the spaces between fibres are filled by binder,

suggesting that the film on the fabrics becomes thicker and covers the fabrics more

uniformly and interfibre interstices.

The micrographs of the dyed modified matrix OSD dyeing system indicated that

although this binder film is beneficial for cotton surface protection, the colour loss

increased, especially under the wet rub conditions and at the higher concentrations.

The SEM micrographs of the wet-rubbed areas, Figures 4.11-4.19, show that when

the formulation concentration increased, the condition of the fabric surface was

increasingly disrupted but that the effect of the pigment type was not significant.

Red and yellow pigment dyed samples were tested with the Martindale abrasion


96

tester, as shown in Table 4.7. The number of rubs, when two yarns were broken, is

almost the same for red and yellow pigment dyed samples. Higher formulation

concentrations increased the number of rubs to break, indicating the fabrics were

being “protected” by the polymer overlayer. When the formulation concentration

was 10g/L, the number of rub cycles was slightly lower than the untreated cotton,

maybe because the binder layer was not thick enough to avoid cotton damage during

high temperature fixation and as it peels away it removes the cotton subsurface as

well. The SEM of abraded fabrics was also observed, Figure 4.20, and again

reflected the same behaviour flat abrasion performance.


fabric on the rub and wash fastness

Formulation

Conc. g/L



Yellow

10 5 4 5 5

100 5 2/3 5 5

150 4/5 2/3 4/5 5

Red

10 4/5 3/4 5 5

100 4/5 2/3 4/5 5

150 4/5 2 4/5 5

Blue

10 4/5 3 5 5

100 4/5 2/3 4/5 5

150 4/5 2 4/5 4/5


fabric on the colour strength

Formulation Conc. g/L λmax (nm) K/S

Yellow

10 430 1.08

100 440 5.98

150 440 7.76

Red

10 570 0.68

100 570 5.17

150 570 6.25

Blue

10 620 0.78

100 610 6.49

150 610 8.18


97


fabric on the Martindale flat abrasion

Formulation Conc. g/L Rubs

(1 Yarn broken)

Rubs

(2 yarns broken)

Yellow

10 12000 12125

100 14025 15375

150 23000 25000

Red

10 10000 10750

100 16500 17750

150 25500 26000

Untreated cotton 0 12500 14000

0 20 40 60 80 100 120 140 160

0.10

0.15

0.20

Ben

din

g S

tiff

nes

s (g

.cm

2/c

m)



fabric on the KES-F bending stiffness, B


98

0 20 40 60 80 100 120 140 160

1.5

2.0

2.5

3.0

3.5

4.0

Sh

ear

Sti

ffn

ess

(g/c

m·d

eg)



fabric on the KES-F shear stiffness, G

0 20 40 60 80 100 120 140 160

5

6

7

8

9

Sh

ear

Hy

ster

esis

(g

/cm

)



fabric on shear hysteresis at 5o, 2HG5


99

(a) Plain cotton

(b) Dry-rubbed (c) Wet-rubbed

Figure 4.7 SEM micrographs of untreated cotton

(a) Binder covered cotton


Figure 4.8 SEM micrographs of 9 g/L binder covered cotton


100



Figure 4.9 SEM micrographs of 90g/L binder covered cotton



Figure 4.10 SEM micrographs of 135 g/L binder covered cotton


101

(a) Dyed cotton



concentration of 10g/L

(a) Dyed cotton



concentration of 100 g/L


102

(a) Dyed cotton




(a) Dyed cotton


Figure 4.14 SEM micrographs of red dyed cotton at a stock formulation



103

(a) Dyed cotton




(a) Dyed cotton





104

(a) Dyed cotton


Figure 4.17 SEM images of blue dyed cotton at stock formulation conc.10g/L

(a) Dyed cotton





105

(a) Dyed cotton



concentration 150g/L

(a) 10g/L

(b) 100g/L (c) 150g/L

Figure 4.20 SEM micrographs of abraded red dyed cotton


106

4.3.2.2 Treatment on PET and Polycotton

Examination of Tables 4.8 and 4.9 indicates the fastness results of cotton, PET and

poly/cotton red pigment Matrix OSD (with softener) dyed fabrics where the dyed

cotton and PET fabrics offer similar performances. Interestingly the poly/cotton

fabric showed better wet fastness than the comparable cotton and polyester fabrics

but the colour strength of pigment dyed cotton fabrics was significantly higher than

the poly/cotton and polyester fabrics, Table 4.9. This effect may be due to the greater

amount of the colourant/binder formulation bonding to the cotton fabric or more

likely an optical effect related to fabric or fibre structure.


cotton, PET and polycotton fabrics on the fastness

Formulation Conc.

g/L

Rub fastness Wash fastness


Cotton

Red 10 4/5 3/4 5 5

Red 100 4/5 2/3 4/5 5

Red 150 4/5 2 4/5 5

PET

Red 10 4 3/4 4/5 5

Red 100 4 2/3 4/5 5

Red 150 4/5 2 4 4/5

Polycotton

Red 10 4/5 4/5 5 5

Red 100 4/5 3 5 5

Red 150 4/5 3/4 5 5


cotton, PET and polycotton fabrics on the colour strength

Formulation Conc. g/L λmax K/S

Cotton

Red 10 570 0.68

Red 100 570 5.17

Red 150 570 6.25

PET

Red 10 570 0.46

Red 100 570 2.44

Red 150 570 3.64

Polycotton

Red 10 570 0.44

Red 100 570 3.51

Red 150 570 5.14


107

4.3.3 Effect of Curing Time on the Performance of the Matrix OSD

System

Although one minute was the recommended curing period for the Matrix OSD

system, a longer period of time was evaluated to establish the optimal cure

conditions. However, it was apparent an increase of the curing time offered no

benefits for dry rub fastness and wash fastness, Tables 4.10-4.12. In contrast for the

wet rub fastness performances there were some marginal benefits for the pale shades,

in terms of extending the curing time to 2-3 minutes. However it is likely when the

additional energy increase is considered, one minute may well be the “best” curing

time in accordance with the Matrix OSD recommendations.

Table 4.10 Effect of different curing times on the fastness of yellow pigment dyed

cotton fabric

Formulation

Conc. g/L

Curing time

min



Yellow 10

1 5 4 5 5

1.5 5 4 5 5

2 5 4/5 5 5

3 5 4/5 5 5

4 5 4 5 5

5 4/5 4 5 5

7 5 4 5 5

Yellow 100

1 5 2/3 5 5

1.5 4/5 3 4/5 5

2 5 3 5 5

3 5 3 5 5

4 4/5 3/4 4/5 5

5 4/5 3/4 4/5 5

7 5 3/4 4/5 5

Yellow 150

1 4/5 2/3 4/5 5

1.5 4/5 2/3 4 5

2 5 3 5 5

3 5 3 5 5

4 4/5 2/3 4/5 5

5 4/5 3 4/5 5

7 5 4 4/5 5


108

Table 4.11 Effect of different curing times on the fastness of red pigment dyed cotton

fabric

Formulation

Conc. g/L

Curing time

min



Red 10

1 4/5 3/4 5 5

1.5 4/5 3/4 4/5 5

2 4/5 3/4 4/5 5

3 4/5 3/4 4/5 5

4 4/5 4 4/5 5

5 4/5 4 4/5 4/5

7 4/5 4 4/5 4/5

Red 100

1 4/5 2/3 4/5 5

1.5 4/5 2 4/5 4/5

2 4/5 2/3 4/5 5

3 4/5 2 4/5 5

4 4/5 3 4/5 5

5 4/5 2/3 4/5 5

7 4/5 2/3 4/5 5

Red 150

1 4/5 2 4/5 5

1.5 4/5 2/3 4 4/5

2 4/5 2 4/5 5

3 4/5 2/3 4/5 5

4 4/5 2/3 4/5 5

5 5 2/3 4/5 5

7 4/5 2/3 4/5 5


109

Table 4.12 Effect of different curing times on the fastness of blue pigment dyed cotton

fabric

4.3.4 Performance of Matrix OSD without Softener System

In this system, the effect of varying pigment formulation concentration was the same

as in the standard matrix OSD system where colour strength increased with pigment

concentration, Table 4.14. However the absence of the silicone softener appears to

have resulted in a decrease in colour strength which may be due to the interaction of

the light with the “reflective” surface silicone layer. Similarly when KES-F fabric

handle parameters were compared, the binder with softener appears to be less stiff,

Figures 4.21-4.23, due the lubricating effect of the silicone softener. However the

Formulation

Conc. g/L

Curing time

min



Blue 10

1 4/5 3 5 5

1.5 4/5 3/4 4 5

2 4/5 4 4/5 5

3 4/5 4 4/5 5

4 4/5 4 4 5

5 4/5 4 4/5 5

7 4/5 4/5 4/5 5

Blue 100

1 4/5 2/3 4/5 5

1.5 4 2/3 4 4/5

2 4/5 2 4/5 4/5

3 4/5 2/3 4/5 4/5

4 4/5 2/3 4/5 4/5

5 4/5 3 4/5 4/5

7 4/5 3 4/5 5

Blue 150

1 4/5 2 4/5 5

1.5 4/5 2 4 4/5

2 4/5 2/3 4 4/5

3 4/5 2/3 4 4/5

4 5 2 4/5 5

5 4/5 3 4/5 5

7 4/5 3 4/5 5


110

reduction in stiffness becomes less obvious as the binder concentration was

increased and interfibre bonding increased.

Examination of the rub and wash fastness data, Table 4.13, indicated that in general

the presence of the softener had a beneficial effect on dry and wet abrasion and wash

fastness. These beneficial effects can be related to the lubricating effect of the

silicone in reducing dry and wet abrasion effects.


rub and wash fastness

Formulation

Conc. g/L



Yellow

10 4/5 4 5 5

100 4/5 3 5 5

150 4/5 3 5 5

Red

10 4/5 3 4/5 5

100 4/5 3 4 4/5

150 4/5 2/3 4 4/5

Blue

10 4/5 3 4 5

100 4 2 3/4 5

150 4 2 3/4 4/5


colour strength

Formulation Conc. g/L λmax K/S

Yellow

10 430 0.90

100 440 4.50

150 440 5.59

Red

10 570 0.62

100 570 4.46

150 570 5.29

Blue

10 620 0.63

100 620 3.85

150 610 6.32


111

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160

0.1

0.2

0.3

0.4

Ben

din

g S

tiff

nes

s (g

.cm

2/c

m)


without softener

with softener

Figure 4.21 Effect of softener incorporated into binder system on the bending

stiffness, B, of pigment dyed cotton fabric

0 20 40 60 80 100 120 140 160

1.5

2.0

2.5

3.0

3.5

4.0

4.5

Shea

r S

tiff

nes

s (g

/cm

¡¤deg

)


without softener

with softener

Figure 4.22 Effect of softener incorporated into binder system on the shear stiffness,

G, of pigment dyed cotton fabric


112

0 20 40 60 80 100 120 140 160

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

Shea

r H

yst

eres

is (

g/c

m)


without softener

with softener

Figure 4.23 Effect of softener incorporated into binder system on the shear hysteresis

at 5o, 2HG5, of pigment dyed cotton fabric

4.4 Conclusions

Matrix OSD pigment dyeing was reported to offer benefits in terms of processing

cost and environmental impact. From initial studies it is apparent that while dry rub

fastness, mechanical rigidity and washing performance are generally acceptable wet

rub fastness presents a technical challenge. On increasing the pigment incorporated

into the surface binder film colour strength increased but fastness properties

decreased and reflect the integrity of the film being compromised by the higher

pigment concentrations.

The pigment dyeability of the cellulosic fabric was better than the 100% polyester

synthetic fabric and poly/cotton blend. However, the blend fabric offers better

fastness than the individual 100% fabrics and further work in this area should be


113

undertaken.

SEM analyses demonstrated the presence of the polymer binder on the fibre surface

and between the fibres at higher application levels. The “protective effect” of the

binder on the cotton fibre/fabric in increasing the number of cycles to failure in the

Martindale Flat Abrasion test was due to this polymer binder overlayer. However,

with the increase of formulation concentration, more pigment was present on the

fabric surface and accordingly caused more colour loss during dry and wet rubbing.

However the presence of these colourants did not affect the fabric integrity/strength

but rather were a visual effect.

The recommended curing time for the Matrix OSD system was one minute and was

recommended as the optimal balance of end-fabric performance and processing

costs. However results in this study indicated marginally enhanced fastness can be

achieved by increasing the cure temperature to 2-3 minutes.

The presence of silicone softener in the binder formulation was found to offer

benefits in terms of colour strength, handle and fastness. These effects were most

likely due to the surface film increasing specular reflectance and lubrication at the

materials interface.

4.5 References

1. Binders for Textile Applications. Cotton Incorporated Technical Bulletin,

2004, ISP(1008): p.1-16.

2. Giesen, V. and Eisenlohr, R., Pigment Printing. Review of Progress in

Coloration and Related Topics, 1994, 24(1): p.26-30.

3. Humphries, A., Muff, J. R., and Seddon, R., Aqueous System for Pigment

Printing, Colourage, 1985, 32(5): p.15-27.


114

4. Bridge, C., Pigment Developments for the Printing Inks for the 90s. Journal

of the Oil & Colour Chemists Association, 1990, 73(7): p.282-284.

5. Khanna, S. R., Pigment Color Printing in Aqueous Phase, Colourage, 1992,

39(3): p.13-16.

6. Friedman, E. A., An Introduction to Phosphate Binders, Kidney International.

Supplement, 2005(96): p.2-6.

7. Wu, Q., Process and Auxiliary of Pigment Pad Dyeing. Dyeing and Finishing,

2007(12): p.3.

8. Yao, D., Surface Modification of Ultra-fine Pigment and Its Dyeing

Performance, Dyeing and Finishing, 2011(4): p.5.

9. Meng, C., An, G., and Cao, Y., Discussion on Pigment Dyeing of Modified

Cotton Fabric, Textile Auxiliaries, 2011, 28(1): p.4.

10. Yang, Y. and Xu, L., Optimization Process for Pad Dyeing of Cotton. Dyeing

and Finishing, 2009(18): p.4.

11. Wei, Q., Surface Modification of Textiles, 2009, Cambridge: Woodhead Pub.

xx, p.337.

12. Vigo, T. L., Textile Processing and Properties : Preparation, Dyeing,


p.479.

13. Hammonds, A. G., Introduction to Binders. Pigment Printing Handbook,

1995, p.57.

Chapter 5 Investigation into the Effect of Crosslinkers, Cationisation and Surface Modification on the Performance

of Matrix OSD Treatments

115

Chapter 5 Investigation into the Effect of

Crosslinkers, Cationisation and Surface

Modification on the Performance of Matrix

OSD Treatments

5.1 Introduction

The purpose of the cationic pre-treatment of cotton was to determine whether

improved dyeability with the pigment binder system could be achieved by

introducing positively charged sites onto the cotton surface. Previous studies have

investigated the effect of cationizing cotton on the colouration of cotton with direct

dyes, acid dyes, reactive dyes, and pigment with improvements in colour yield and

colour fastness reported [1, 2]. For pigment dyeing, modification of the pigment

dyeing system to achieve better results has been studied through the use of

fastness-improving reagents and of nanoscale pigment dispersion [3, 4]. In this

investigation, cotton has been modified using a cationic reagent Cibafix ECO which

is proprietary polyethylene polyamine manufactured and supplied by Ciba Specialty

Chemicals. It is also free from formaldehyde and zinc, and used in the dyeing

industry as a wet fastness modifier to improve dyeing [5]. Wang and Zhang have

recently evaluated Cibafix ECO as a means to improve pigment printing (not

pigment dyeing), and reported that the rub fastness improved and was only

acceptable when the fastness-improving reagent was applied [3].

The binder film which links fabrics and pigment is formed during the dry heat fixing

process which usually consists of dry heat and a change in pH value, bringing about

either self-crosslinking or reaction with other suitable crosslinking agents [2]. In this



116

chapter, four crosslinkers (Nanolink, citric acid, Dimethylol Dihydroxy Ethylene

Urea (DMDHEU) and Knittex MLF NEW) were used in the binder system.

Although Matrix OSD is a self-crosslinking binder, these preliminary studies were

undertaken to explore the effect of external crosslinkers in this binder system and if

possible further benefits could be identified.

In this chapter, fabrics were also pretreated by ultraviolet/ozone (UVO) with the

view to specifically modifying the surface interface as distinct from the bulk

modifications which would also affect the surface. UVO treatments were originally

considered as a surface cleaning method which was used to modify the surface

chemistry and improve the wetting characteristics of natural and synthetic polymers

[6, 7]. It functions through the combined effects of UV light and ozone produced in

situ from a gas phase photo-dissociation of molecular oxygen. Previous studies have

indicated the efficacy of UVO treatments in removing surface hydrophobes from

wool and other material surfaces, imparting wettability and improving dyeability

and shrink resistance [8, 9].

Much research has been conducted on the dyeing of cotton has focused on changing

the bulk and surface chemistry, through related processing such as dyeing, bleaching,

and washing. However, in most of the relative dyeing studies, the colourants used

were dyes, not pigments.



117

5.2 Experimental Work

5.2.1 Materials

Fabrics 100% bleached plain woven cotton fabric, 191.5g/m2, was also

supplied by Whaleys, UK.

Pigments Lyosperse red 2BN LIQ was supplied by Huntsman, UK.

Lyosperse yellow MR LIQ was supplied by Huntsman, UK.

Minerprint blue B, was supplied by Quality Colours, UK.


Switzerland.


Crossliners Nanolink was supplied by Devan-PPT Chemicals, UK.

Citric acid was purchased from Aldrich Chemicals, UK.

DMDHEU was kindly supplied by Huntsman, UK.

Knittex MLF NEW was supplied by Huntsman, UK.

5.2.2 Pigment Dyeing System

The standard Matrix OSD dyeing system, discussed in 4.2.4 was used as the pigment

dyeing system in this project component.

5.2.3 Fabric Pretreatment by Cationic Fixing Agent

Before applying the pigment dyeing solution onto the cotton fabric, the cationic

fixing agent Cibafix ECO was applied as a pre-treatment to the fabrics at

concentrations of 0.5%, 1% and 2% on the weight of fabric (owf) by an exhaustion

method at 40℃ for 30 minutes with a liquor to fabric ratio of 20:1. After rinsing in

water and air-drying, the treated fabrics were then pigment-dyed under standard

conditions.



118

5.2.4 Crosslinker Treatment

Nanolink

Cotton fabrics were pre-treated with 2.0% o.w.f. Nanolink by exhaustion from a

treatment bath at pH5, adjusted with acetic acid, and the exhaustion bath

temperature was heated from 20℃ to 40℃ for 10 minutes. After rinsing in water

the fabrics were air-dried, and then pigment-dyed under standard conditions (in

4.2.4).

Citric Acid

Two different kinds of citric acid applications were evaluated, as a pre-treatment and

incorporation of the citric acid into the treatment formulation.

a. The cotton fabrics were padded at 80% w.p.u., with the concentrations of 1g/L,

3g/L, 5g/L, 10g/L, 20g/L, 40g/L, 60g/L, 100g/L and 140g/L citric acid solutions

with the same amount of sodium hypophosphite incorporated. The fabrics were

dried at 100℃ for 3 minutes and then heat cured at 180℃ for 90 seconds. The

fabrics were rinsed in water and were then air-dried, followed by standard

pigment-dyeing (in 4.2.4).

b. Citric acid was incorporated with the pigment dyeing solution at the same

concentration as stated in previous method and pigment dyed under standard

conditions (in 4.2.4).

Knittex MLF New

Two different kinds of Knittex MLF New applications were performed, either as a

pre-treatment and incorporated into the pigment dyeing formulation.

a. The cotton fabrics were pre-treated with either 40g/L or 60g/L Knittex MLF

New by padding 80% w.p.u., drying at 100℃ for 3 minutes and then heat



119

curing at 180℃ for 90 seconds. The fabric samples were then pigment dyed

under standard conditions.

b. Knittex MLF New, 40-60 g/L, was combined with the pigment dyeing solution

and then pigment dyed as reported earlier.

Citric Acid with Knittex MLF New

The cotton fabrics were pre-treated with a citric acid and Knittex MLF New

combination, which was padded at 80% w.p.u. at the concentration of 40g/L and

60g/L, dried at 100℃ for 3 minutes, heat cured at 180℃ for 90 seconds and then

pigment dyed.

DMDHEU

The cotton fabrics were pre-treated with 100g/L DMDHEU and 10g/L magnesium

chloride, padded at 80% w.p.u., dried at 100℃ for 3 minutes, heat cured at 180℃

for 90 seconds. Following water rinsing and air drying the fabric samples were

pigment-dyed.

5.2.5 UVO treatment

Before fabric samples were dyed with the standard Matrix OSD system, the cotton

fabrics were pre-treated by UVO for 5, 10 and 15 minutes on each face of the fabric.



120


5.3.1 Effect of Cationization Treatment

Cationization of the cotton fabrics improved the wet rub fastness for the yellow

pigment dyed fabrics but offered almost no effect on the dry rub fastness, Table 5.1.

However surprisingly for the red and blue pigment dyed fabrics the cationic fixing

agent had relatively little effect on the fastness properties. Interestingly, cationization

treatment caused more change of colour after washing when 0.5% and 1% cationic

fixing agent were applied. When 2% cationic fixing agent was applied, the change of

colour after washing was better than with 0.5% and 1% cationic fixing agent, however,

the results are still lower than the control reference samples. It may be because the

temperature, at which Cibafix ECO can improve wash fastness, is identified as 50℃

in the Ciba technical data sheet, but the washing temperature used in this study was

60℃.

The colour strength K/S of the pigment dyed fabrics appeared to increase with

increasing application levels of the cationic reagent to the cotton, Figure 5.1. This

may be related to increased exhaustion of the pigment dyeing formulation onto the

positively charged fabric.



121

Table 5.1 Effect of varying the cationic fixing agent concentration on the fastness of

pigment dyed cotton fabric

Formulation

Conc. g/L

Cationic fixing

agent %


Dry Wet Colour change Staining

Yellow 10

0 5 4 5 5

0.5 4/5 4 4/5 5

1 4/5 4 4/5 4/5

2 4/5 4/5 5 5

Yellow 100

0 5 2/3 5 5

0.5 4/5 3/4 4/5 4/5

1 4/5 4 5 4/5

2 4/5 4 5 4/5

Yellow 150

0 4/5 2/3 4/5 5

0.5 4/5 3/4 4/5 4/5

1 4/5 3 5 4/5

2 4/5 3/4 4/5 4/5

Red 10

0 4/5 3/4 5 5

0.5 4 3 4/5 5

1 4 3 4/5 4/5

2 4/5 4 4/5 5

Red 100

0 4/5 2/3 4/5 5

0.5 4 2 3/4 4

1 4/5 2 3/4 4/5

2 4/5 2/3 4 4/5

Red 150

0 4/5 2 4/5 5

0.5 4 2 3/4 4

1 4 2/3 4 4/5

2 4/5 2/3 4 4/5

Blue 10

0 4/5 3 5 5

0.5 4 3 4 5

1 4 3 4/5 4/5

2 3/4 3 4/5 5

Blue 100

0 4/5 2/3 4/5 5

0.5 4 2 3/4 4/5

1 4 2/3 3/4 4/5

2 4 2/3 4 4/5

Blue 150

0 4/5 2 4/5 4/5

0.5 4 2 3/4 4/5

1 4 2/3 4 4/5

2 4 2/3 4/5 4/5



122

Figure 5.1 Effect of varying the cationic fixing agent concentration on the colour

strength of pigment dyed cotton fabric

5.3.2 Effect of Crosslinkers

5.3.2.1 Effect of Nanolink

Nanolink is reported by Devan-PPT to function effectively as a covalent linking

agent and increase surface adhesion between coatings and the fibre substrate.

However it is apparent that Nanolink imparts no beneficial effects on dry rub

fastness and may even slightly decrease performance for darker colours, Table 5.2.

However, the Nanolink pre-treatment clearly improved the wet rub fastness for all

colours and shades, especially for the yellow pigment shades. Wash fastness is rated

as excellent similar to the standard control samples.



123

Table 5.2 Effect of 2% o.w.f. application of Nanolink on the fastness properties of of


a- treated

b- reference control

5.3.2.2 Effect of Citric Acid

When citric acid was incorporated into the pigment dyeing system, insoluble

precipitates substrates appeared in the solution. Heating the solution and changing

the addition order into the aqueous formulation were assessed, but the deposits still

formed. Therefore, only pre-treatment of the fabric with citric acid was examined.

As can be seen from the data in Table 5.3-5.5, when the fabrics were pre-treated

with citric acid, the wet rub fastness was improved, especially for the light colours.

In contrast the dry rub fastness and wash fastness remained relatively unchanged but

still at commercially acceptable performance levels. The wet rub fastness

performance levels at the 5g/L concentration and most likely functions by reducing

the swelling of crosslinked cotton interface and maintaining coating adhesion. The

samples were also pre-treated with citric acid at 40g/L, 60g/L, 100g/L and 140g/L,

but the results showed no additional benefit. The results at 40g/L and 60g/L will be

presented in Table 5.3-5.5 to compare with Knittex MLF New treatments.

Formulation

Conc. g/L



a b a b a b a b

Yellow

10 5 5 4/5 4 5 5 5 5

100 4/5 5 4 2/3 5 5 5 5

150 4/5 4/5 4 2/3 5 4/5 5 5

Red

10 4/5 4/5 3/4 3/4 5 5 5 5

100 4/5 4/5 3 2/3 4/5 4/5 5 5

150 4/5 4/5 2/3 2 5 4/5 5 5

Blue

10 4/5 4/5 3/4 3 4/5 5 5 5

100 4 4/5 3/4 2/3 5 4/5 5 5

150 4 4/5 3 2 5 4/5 5 5



124

Table 5.3 Effect of citric acid pre-treatment of cotton on the fastness of the yellow

pigment dyed fabric

Formulation

Conc. g/L

Citric acid

g/L



Yellow 10

0 5 4 5 5

1 5 4 5 5

3 5 4/5 5 5

5 4/5 4/5 4/5 5

10 4/5 4/5 4/5 5

20 4/5 4/5 4/5 5

Yellow 100

0 5 2/3 5 5

1 5 2/3 4/5 5

3 5 3/4 4/5 5

5 5 4 4/5 5

10 4/5 3/4 4/5 5

20 4/5 4 4/5 5

Yellow 150

0 4/5 2/3 4/5 5

1 4/5 2 4/5 5

3 5 3 4/5 5

5 4/5 4 4/5 5

10 4/5 3/4 4/5 5

20 4/5 3 4/5 5



125

Table 5.4 Effect of citric acid pre-treatment of cotton on the fastness of the red

pigment dyed fabric

Formulation

Conc. g/L

Citric acid

g/L



Red 10

0 4/5 3/4 5 5

1 4/5 3/4 4/5 5

3 4/5 4 4/5 5

5 4/5 4 4/5 5

10 4/5 4 4/5 5

20 4/5 4 4/5 5

Red 100

0 4/5 2/3 4/5 5

1 4/5 3 4/5 4/5

3 4/5 3/4 4/5 4/5

5 4/5 3/4 4/5 4/5

10 4/5 2/3 4/5 5

20 4/5 3 4/5 5

Red 150

0 4/5 2/3 4/5 5

1 4/5 2/3 4 4/5

3 4/5 3 4/5 4/5

5 4/5 3 4/5 4/5

10 4/5 2/3 4/5 4/5

20 4/5 2/3 4/5 5



126

Table 5.5 Effect of citric acid pre-treatment of cotton on the fastness of the blue

pigment dyed fabric

5.3.2.3 Effect of Knittex MLF New

The effect of pre-treatment of the pigment dyed cotton fabric with Knittex MLF

New, Table 5.6, was to significantly improve the wet rub fastness at both low and

high pigment levels while the dry rub fastness and wash fastness remain

commercially acceptable. Increasing the application concentration from 40g/L to

60g/L had little benefits, so 40g/L was selected for further work.

After identifying the benefit of Knittex MLF New pre-treatment, the effect of a

combined pigment dyeing treatment incorporating Knittex MLF New was also

Formulation

Conc. g/L

Citric acid

g/L



Blue 10

0 4/5 3 5 5

1 4/5 4 4/5 5

3 4/5 4 4/5 5

5 4/5 4 4/5 4/5

10 4/5 4 4/5 4/5

20 4/5 3/4 4/5 4/5

Blue 100

0 4/5 2/3 4/5 5

1 4/5 3 4/5 4/5

3 4/5 3 4/5 4/5

5 4/5 3 4/5 4/5

10 4/5 3 4/5 4/5

20 4/5 3 4/5 4/5

Blue 150

0 4/5 2 4/5 5

1 4/5 2/3 4 4/5

3 4/5 3 4 4/5

5 4/5 2/3 4 4/5

10 4/5 2/3 4 4/5

20 4 2/3 4 4/5



127

assessed. However the improvement in the wet rub fastness performance results was

not as good as the pre-treated fabrics, Table 5.7. Samples probably due to the

increased wet swelling and lower cohesion between the coating and the fibre

interface. Nevertheless it was still beneficial for wet rub fastness particularly for the

light pale shade, especially at the concentration of 40g/L.

Table 5.6 Effect of the application of Knittex MLF New pre-treatment to cotton on

the fastness of pigment dyed fabric

Formulation

Conc. g/L

Knittex

g/L



Yellow 10

0 5 4 5 5

40 5 4/5 4/5 5

60 5 4/5 4/5 5

Yellow 100

0 5 2/3 5 5

40 4/5 4 4/5 5

60 4/5 3/4 4/5 5

Yellow 150

0 4/5 2/3 4/5 5

40 4/5 4 4/5 5

60 4/5 4 4/5 5

Red 10

0 4/5 3/4 5 5

40 4/5 4 4/5 5

60 4/5 4 4/5 5

Red 100

0 4/5 2/3 4/5 5

40 4/5 3/4 4/5 5

60 4/5 3 4/5 5

Red 150

0 4/5 2 4/5 5

40 4/5 3/4 4/5 5

60 4/5 4 4/5 5

Blue 10

0 4/5 3 5 5

40 4/5 4 4/5 5

60 4/5 3/4 4/5 4/5

Blue 100

0 4/5 2/3 4/5 5

40 4/5 3/4 4/5 5

60 4/5 4 4/5 5

Blue 150

0 4/5 2 4/5 5

40 4/5 4 4/5 5

60 4/5 3/4 4/5 5



128

Table 5.7 Effect of incorporating Knittex MLF New into the pigment dyeing

formulation applied to cotton fabric on colour fastness

5.3.2.4 Effect of Citric Acid and Knittex MLF New

The effect on pigment dyeing fastness by pre-treating the cotton fabric with a

combination of citric acid and Knittex MLF New and treating with a combination

mixture of Knittex MLF New and citric acid at 40g/L and 60g/L, shown in Tables

Formulation

Conc. g/L

Knittex

g/L



Yellow 10

0 5 4 5 5

40 5 5 5 5

60 5 4/5 4/5 5

Yellow 100

0 5 2/3 5 5

40 5 4 4/5 5

60 5 3 4/5 5

Yellow 150

0 4/5 2/3 4/5 5

40 4/5 3 4/5 5

60 5 3/4 4/5 5

Red 10

0 4/5 3/4 5 5

40 5 4/5 4/5 5

60 5 4/5 4/5 5

Red 100

0 4/5 2/3 4/5 5

40 4/5 2 4/5 5

60 4/5 2/3 4/5 5

Red 150

0 4/5 2 4/5 5

40 4/5 3 4/5 5

60 4/5 3 4/5 5

Blue 10

0 4/5 3 5 5

40 4/5 4 4/5 5

60 4/5 4 4/5 5

Blue 100

0 4/5 2/3 4/5 5

40 4 3 4/5 5

60 4 2 4/5 5

Blue 150

0 4/5 2 4/5 5

40 4 3/4 4/5 5

60 4/5 2/3 4/5 5



129

5.8-5.10. The obvious drawback of pre-treating with the mixture of citric acid and

Knittex MLF New was observed in the wet rub fastness and dry rub fastness

performances, where lower fastness than the control fabrics in almost all colours and

shades was demonstrated. The addition of citric acid offers almost no benefit for

fastness, while Knittex MLF New imparts significant improvement on wet rub

fastness. As mentioned in Section 5.3.2.3, 40g/L Knittex MLF New shows the better

application concentration.


fastness performance of yellow pigment dyed cotton fabric

Formulation

Conc. g/L

Citric acid

g/L

Knittex

g/L



Yellow 10

0 0 5 4 5 5

40 0 5 4/5 5 5

60 0 5 4/5 5 5

0 40 5 4/5 4/5 5

0

40

60

60

40

60

5

4/5

4/5

4/5

4

3/4

4/5

5

4/5

5

5

5

Yellow 100

0 0 5 2/3 5 5

40 0 4/5 2/3 4/5 5

60 0 4/5 2/3 4/5 5

0 40 4/5 4 4/5 5

0

40

60

60

40

60

4/5

4/5

4

3/4

2/3

1/2

4/5

4/5

4/5

5

5

5

Yellow 150

0 0 4/5 2/3 4/5 5

40 0 4/5 2 4/5 5

60 0 4/5 2 4/5 5

0 40 4/5 4 4/5 5

0

40

60

60

40

60

4/5

4

4/5

4

1/2

1/2

4/5

4/5

4/5

5

5

5



130


fastness performance of red pigment dyed cotton fabric

Formulation

Conc. g/L

Citric acid

g/L

Knittex

g/L



Red 10

0 0 4/5 3/4 5 5

40 0 4/5 4 5 5

60 0 4/5 4 5 5

0 40 4/5 4 4/5 5

0

40

60

60

40

60

4/5

4/5

4

4

4

3

4/5

5

4/5

5

5

5

Red 100

0 0 4/5 2/3 4/5 5

40 0 4/5 2/3 4/5 5

60 0 4/5 2/3 4/5 5

0 40 4/5 3/4 4/5 5

0

40

60

60

40

60

4/5

4

4

3

2

1/2

4/5

4/5

4/5

5

4/5

4/5

Red 150

0 0 4/5 2 4/5 5

40 0 4/5 2 4/5 5

60 0 4/5 2 4/5 5

0 40 4/5 3/4 4/5 5

0

40

60

60

40

60

4/5

4

4

4

2/3

1/2

4/5

4/5

4/5

5

4/5

4/5



131


fastness performance of blue pigment dyed cotton fabric

5.3.2.5 Effect of DMDHEU Pre-Treatment

Table 5.11 presents that the fastness results of cotton fabrics pre-treated with 100g/L

DMDHEU. The data indicates that the DMDHEU modification to the cotton fabric

has a lesser benefit than the Knittex MLF New for the wet rub fastness while dry rub

fastness and wash fastness still remain good. It is likely the difference was due to the

greater crosslinking and embrittlement of the fibre.

Formulation

Conc. g/L

Citric acid

g/L

Knittex

g/L



Blue 10

0 0 4/5 3 5 5

40 0 4/5 3/4 4/5 5

60 0 4/5 3/4 4/5 5

0 40 4/5 4 4/5 5

0

40

60

60

40

60

4/5

4/5

4

3/4

4

4

4/5

5

4/5

4/5

4/5

5

Blue 100

0 0 4/5 2/3 4/5 5

40 0 4 2/3 4/5 5

60 0 4 2/3 4/5 5

0 40 4/5 3/4 4/5 5

0

40

60

60

40

60

4/5

3/4

3

4

2

2

4/5

4/5

4/5

5

4/5

4/5

Blue 150

0 0 4/5 2 4/5 5

40 0 4 2/3 4/5 5

60 0 4 2/3 4/5 5

0 40 4/5 4 4/5 5

0

40

60

60

40

60

4/5

3/4

4

3/4

1/2

2

4/5

4

4

5

4/5

4/5



132

Table 5.11 Effect of 100g/L DMDHEU pre-treatment on the fastness performance of


a- Treated by DMDHEU

b- Reference

5.3.3 Effect of UVO Treatment

In previous studies UVO treatment has been used to modify the fabric surface and

improve dyeability and the effectiveness of polymer coating, however in this study

of pigment dyed cotton, the results indicate that UVO treatment imparts relatively

lower fastness performance than the original untreated cotton fabrics. There is a

clear reduction in wet rub fastness and the wash fastness is also adversely affected

by the UVO pre-treatment. The worst colour changing results are observed with the

darkest colours and is probably related to the change in adhesion properties

following surface oxidation. However the cross-staining values are unaffected

indicating the removed colour has little affinity for the test fabrics. Figure 5.2

illustrates that the colour was changed after UVO treatment, probably due to the

yellowness imparted by the treatment.

Formulation Conc.

g/L



a b a b a b a b

Yellow

10 5 4/5 4/5 3/4 5 5 5 5

100 4/5 4/5 3 2/3 5 4/5 5 5

150 4/5 4/5 2/3 2 4/5 4/5 4/5 5

Red

10 4/5 5 4 4 4/5 5 5 5

100 4/5 5 2/3 2/3 4/5 5 5 5

150 4/5 4/5 2/3 2/3 4/5 4/5 5 5

Blue

10 4/5 4/5 3/4 3 4/5 5 5 5

100 4/5 4/5 3 2/3 4/5 4/5 5 5

150 4 4/5 2/3 2 4/5 4/5 5 5



133

Table 5.12 Effect of UVO treatment on the fastness performance of pigment dyed

cotton fabric

Formulation Conc.

g/L

Time in UVO

min



Yellow 10

0 5 4 5 5

5 4/5 3 3/4 5

10 4/5 3 3/4 5

15 4/5 3 3 5

Yellow 100

0 5 2/3 5 5

5 4/5 2/3 3 5

10 4/5 2 3 5

15 4/5 2 2/3 5

Yellow 150

0 4/5 2/3 4/5 5

5 4/5 2/3 3/4 5

10 4/5 2 3/4 5

15 4/5 1/2 3 5

Red 10

0 4/5 3/4 5 5

5 4/5 3 3/4 5

10 4/5 3 3/4 4/5

15 4/5 3 3 5

Red 100

0 4/5 2/3 4/5 5

5 4/5 2 3/4 4

10 4/5 2 3 4/5

15 4/5 2/3 2/3 4/5

Red 150

0 4/5 2 4/5 5

5 4/5 2 4 4/5

10 4 2 2/3 4/5

15 4 2 2/3 4/5

Blue 10

0 4/5 3 5 5

5 4/5 3 2/3 4/5

10 4/5 2/3 2/3 4/5

15 4 2/3 2 4/5

Blue 100

0 4/5 2/3 4/5 5

5 4 1/2 2/3 4/5

10 4 1/2 2 4/5

15 4 1/2 1/2 4/5

Blue 150

0 4/5 2 4/5 4/5

5 4 2 3 5

10 4 2 2 5

15 4 1/2 1/2 4/5



134

Figure 5.2 Effect of UVO exposure on the colour strength of pigment dyed cotton

fabric

From the SEM analyses of the abraded standard pigment dyed cotton Section 4.3.2,

the presence of the colourants was not the reason for surface degradation. Therefore

in this study discussion, only the red pigment dyed samples were examined. After

UVO treatment, the degradation showed the same behaviour as the pigment

dyed-only fabric samples, i.e. when the concentration of formulation rises, there was

more binder evident on the fabric. Comparing the dry-rubbed areas with the

wet-rubbed areas, it was apparent that the wet-rubbed areas were damaged more.

The effect of increasing UVO treatment time on rubbing damage is illustrated in

Figures 5.3-5.11. At the concentration levels of 100g/L and 150g/L, the damage

appearance was more obvious with the increase of UVO treatment time.



135

(a) Dyed cotton



stock formulation concentration

(a) Dyed cotton






136

(a) Dyed cotton




(a) Dyed cotton






137

(a) Dyed cotton




(a) Dyed cotton






138

(a) Dyed cotton




(a) Dyed cotton






139

(a) Dyed cotton




5.4 Conclusions

Cationizing the cotton fabrics prior to pigment dyeing improved the wet rub fastness

performance of the Matrix OSD dyeing system, but the other fastness properties

were in general unchanged.

It was apparent from the results of the crosslinker studies, that the colour fastness

was influenced by the crosslinking treatment which improved the link between

binder and fabrics. The pre-treatment approach appears more suitable to the

crosslinker application than the combined application method to improving the wet

rub fastness. Moreover, the crosslinker has almost no effect on wash fastness which

always remains at an acceptable performance level with most crosslinkers. In

comparison the Knittex MLF New pre-treatment at 40g/L offered the best option to

improve the colour fastness.



140

Unlike the benefits of UVO pre-treatment previously observed for other fabric

dyeing studies, in this study it was established that the pigment dyeing performance

was reduced after the sensitised photo-oxidation treatment. The reason for this

worsening of performance is unclear but it is perhaps due to changed fibre surface

chemistry not encouraging binding to the pigment dyeing system.

5.5 References

1. Lu, Y. and C. Q. Yang, Fabric Yellowing Caused by Citric Acid as a

Crosslinking Agent for Cotton, Textile Research Journal, 1999, 69(9):

p.685-690.

2. Waris, M., Effect of Crosslinking in Textile Pigment Printing and

Enhancement of Fastness Properties. Journal of the Chemical Society of

Pakistan, 2009, 31(1): p.145-150.

3. Wang, C. X. and Y. H. Zhang, Effect of Cationic Pre-treatment on Modified

Pigment Printing of Cotton. Materials Research Innovations, 2007, 11(1):

p.27-30.

4. Fang, K. J., Dyeing of Cationised Cotton Using Nanoscale Pigment

Dispersions. Coloration Technology, 2005, 121(6): p.325-328.

5. Bogle, M., Textile Dyes, Finishes, and Auxiliaries. Revised edn. 1977, New

York ; London, Garland Publishing. xiii, p.168.


Academic & Professional. xiii, p. 361.

7. Fritz, A. and Cant, J., Consumer Textiles, 1986, Melbourne: OUP.

8. Parfitt, M., Investigation into the Surface Chemistry of Cotton Fibres,

UMIST PhD Thesis, 2001.

9. Shao, J., Hawkyard, C. J., and Carr, C. M., Investigation into the Effect of

UV/ozone Treatments on the Dyeability and Printability of Wool, Journal of

the Society of Dyers and Colourists, 1997, 113(4): p.126-130.

Chapter 6 Investigation into the Effect of Flurocarbon Treatments on Matrix OSD Treated Fabric Performance

141


Flurocarbon Treatments on Matrix OSD

Treated Fabric Performance

6.1 Introduction

Fluorine-based finishing agents are an important class of effect chemicals used in

textiles because they can provide combined water and oil repellency without

impairing the air permeability or modifying the handle of textiles [1]. The benefit of

fluorocarbon finishes in imparting water and oil repellency to textile fabrics has

been studied previously but more recently new research has focused on plasma

polymerized fluorocarbon films [2-5]. However there are few studies relating colour

properties to fluorocarbon treatment, especially for pigment colouration.

In this chapter, the performance of fluorocarbon treatments on fabrics treated with

Matrix OSD system was investigated. Five different fluorocarbon treatments were

applied to the cotton fabrics either by pre-mixing with the pigment dyeing system or

as an after-treatment. Rub fastness, wash fastness, colour strength, abrasion

resistance, water/oil repellency, SEM and handle properties were examined in order

to establish the effects of fluorocarbon treatment on the pigment dyeing system. In

addition the Matrix OSD without softener, discussed in Chapter 4, was also assessed

in order to compare the water and oil repellency with that of the Matrix OSD system

with softener. The aim was to study the possible deleterious effect of the silicone

softener in the Matrix OSD binder on the fluorocarbon oil repellency treatment.


142

6.2 Experimental Work

6.2.1 Materials

Fabrics 100% bleached plain cotton fabric, 191.5g/m2, was supplied by

Whaleys, Bradford, UK.

45/55 plain woven polycotton, 125 g/m2, were supplied by

Phoenix Calico, Stalybridge, UK.





Switzerland.

Matrix OSD, without softener, was supplied by Beyond Surface

Technologies, Switzerland.


Fluorocarbon

and related

chemicals

Scotchguard FC3548 was supplied by 3M, UK.

Shield F-01, Shield FRN-6 and Shield Extender FCD were

supplied by Beyond Surface Technologies, Switzerland.

Oleophobol 7713 and Hydrophobol XAN were supplied by

Huntsman, UK.

Rucoguard LAD was supplied by Rudolf Chemicals, UK.

6.2.2 Dyeing System

The modified Matrix OSD system discussed in Chapter 4 was used as the pigment

dyeing system in this study.


143

6.2.3 Fluorocarbon Treatment

The cotton fabrics were treated by five different fluorocarbons:

Scotchguard FC3548;

Shield F-01 with Shield Extender FCD;

Shield FRN-6;

P2i fluorocarbon plasma polymerisation process;

Oleophobol 7713 with Hydrophobol XAN.

6.2.3.1 Scotchguard FC3548

The fabrics were treated by FC3548 by two different methods, incorporation into

dyeing formulation and as an after-treatment.

a. FC3548 was incorporated with pigment dyeing solution at a concentration of

5g/L, 10g/L, 30g/L and 50g/L. The subsequent dyeing procedure followed the

standard pigment dyeing system;

b. The pigment-dyed samples were after-treated by FC3548 at the same

concentrations as stated in Method a. The pigment-dyed samples were padded

with the FC3548 solution, squeezed to 80% w.p.u., dried at 110℃ for 3 minutes

and then cured at 180℃ for 1 minute.

6.2.3.2 Shield F-01 with Shield Extender FCD

Both pigment-dyed cotton and polycotton samples were after-treated by Shield F-01

with Shield extender FCD. Before Shield F-01 and Shield extender FCD were added

into the bath, the pH of the bath was adjusted to between 4.0 and 5.0 by acetic acid.

The concentrations of applied chemicals are presented in Table 6.1. The

pigment-dyed samples were padded with the treating solution at 80% w.p.u., dried at

110℃ for 3 minutes and cured at 170℃ for 1 minute.


144

Table 6.1 Concentration of Shield F-01aftertreating system

Shield F-01 Conc.

g/L

Shield Extender FCD Conc.

g/L

Wetting agent Conc.

g/L

a 20 8 1

b 40 8 1

c 60 8 1

6.2.3.3 Shield FRN6

The pigment-dyed samples were after-treated by Shield FRN6 at 30g/L, 45g/L and

60g/L. The padding bath pH was adjusted between 4.0 and 5.0 by acetic acid.

Wetting agent was added at the concentration of 2g/L. The samples were padded

with the FRN6 solution at 80% w.p.u., dried at 110℃ for 3minutes and then cured

at 170℃ for 40 seconds.

6.2.3.4 P2i

The pigment-dyed samples were after-treated by P2i under three conditions:.

Process 1: ½monomer, flow 40 mTorr, Pw 40min;

Process 2: ½monomer, flow 40 mTorr, Pw 70min;

Process 3: Standard Process.

6.2.3.5 Oleophobol 7713 with Hydrophobol XAN

The fabrics were treated with the Oleophobol 7713 and Hydrophobol XAN

combination either by incorporation into the pigment dyeing formulation or as

after-treatment:

a. Oleophobol 7713 and Hydrophobol XAN were added into the pigment dyeing

solution. The concentrations of Oleophobol 7713 applied were 40g/L and 60g/L


145

while the concentration of Hydrophobol XAN was 10g/L. Before they were

added into the dyeing solution, the bath pH was adjusted first to 5-7 by acetic

acid and the cotton fabrics were treated by the standard pigment dyeing system

process;

b. Alternatively after pigment dyeing, the samples were after-treated by

Oleophobol 7713 and Hydrophobol XAN at the same concentrations as stated in

Method a. The formulation pH was adjusted to between 5.0 and 7.0 using acetic

acid. After the bath was prepared, the pigment-dyed samples were padded at 80%

w.p.u., dried at 110℃ for 3 minutes and then cured at 170℃ for 90 second.

6.2.3.6 Rucoguard LAD and Oleophobol 7713

The plain cotton and red pigment dyed samples were treated with 7% owf

Rucoguard LAD and 8% owf Oleophobol 7713 with a liquor-to-goods ratio of 10:1

by exhaustion and padding method. The bath pH was adjusted to 4-5 by the addition

of acetic acid. The red samples were dyed by both Matrix OSD system and Matrix

OSD without softener system.

a. The plain cotton and red pigment dyed samples were treated with treating

solution at 20℃ for 20 minutes. Then the temperature was raised from 20℃ to

40℃ for another 20 minutes and kept at 40℃ for 20 minutes. After that, the

treated samples were dried at 110℃ for 90 seconds and cured at 160℃ for 1

minute.

b. The plain cotton and red pigment dyed samples were padded at 80% wet pick up,

dried at 110℃ for 90 seconds and cured at 160℃ for 1 minute.


146


6.3.1 Effect of Scotchguard FC3548

Table 6.2 presents the fastness results of the combined Scotchguard FC3548/Matrix

OSD treated cotton fabric. Comparing the control 0g/L FC3548 treated fabric with

the combined FC3548 formulations indicates there was a clear beneficial effect on

the wet rub fastness while dry rub fastness and wash fastness remained relatively

unchanged. At the high concentrations of FC3548 the dry rub fastness was decreased,

especially for medium and dark colours (red and blue). Similarly although the

increasing concentration of FC3548 improved the wet rub fastness, it was reduced at

the highest application level, 50g/L. Therefore, the optimal treatment concentration

was 30g/L FC3548 and reflected the surface frictional properties of the film and its

cohesion and durability.

The effect of applying the fluorocarbon FC3548 on the fabric colour strength is

variable, Figure 6.1. The co-application of FC3548 improved colour yield at light

and dark colours (yellow and blue), whilst it decreased K/S at medium colour

strength (red). The nature of variability is uncertain but overall the colour change is

not perceived as a “problem”.

Table 6.3 presents the fastness results of red pigment dyed fabrics, which were

after-treated by FC3548. It is apparent that the Scotchguard FC3548 after-treatment

is beneficial in improving the wet and dry fastness performance and the optimal

application level would be 5g/L FC3548. In comparison to the pre-mixing

application, which offers “best” performance at 30g/L, the after-treatment method

appears to offer the better protection. Figure 6.2 illustrates the colour strength of the

control fabrics and red pigment dyed samples after-treated by FC3548. There

appears to be little colour change following the after-treatment.


147

Table 6.4 presents the abrasion results for fabrics treated both by incorporating the

fluorocarbon into the pigment dyeing formulation and aftertreating the dyed fabrics

with fluorocarbon. The use of FC3548 decreased the number of rub cycles to two

yarns broken, the abrasion resistance reducing with the increase of the fluorocarbon

concentration. The number of rub cycles to failure for these two treatment methods

are almost the same.

Figures 6.3-6.14 shows the SEM micrographs of pigment red-dyed fabrics

aftertreated with FC3548 at increasing concentrations. It is evident that the

wet-rubbed areas are damaged more than dry-rubbed area which is the same as

observed with the micrographs of the control samples shown in Figures 4.14-4.16.

The effect of FC3548 was hardly observed from these micrographs, however,

compared with the reference images, Figure 4.14-4.16, the rubbed damage is less

and the surface is smoother, especially for wet rub fastness. This may be caused by

the repellent function imparted by FC3548.


148

Table 6.2 Effect of varying FC3548 concentration within the pigment dyeing

formulation on the fastness of coloured cotton fabric

Formulation

Conc. g/L

FC3548

g/L



Yellow 10

0 5 4 5 5

5 4/5 4/5 5 5

10 4/5 4/5 5 5

30 4/5 4/5 5 5

50 4/5 4/5 5 5

Yellow 100

0 5 2/3 5 5

5 4/5 3 5 5

10 4/5 4 5 5

30 4/5 4/5 5 5

50 4 4 5 5

Yellow 150

0 4/5 2/3 4/5 5

5 4/5 3/4 5 5

10 4/5 4 5 5

30 4/5 4/5 5 5

50 4 4 5 5

Red 10

0 4/5 3/4 5 5

5 4/5 4/5 5 5

10 4/5 4/5 5 5

30 4/5 4/5 5 5

50 4 4/5 4/5 5

Red 100

0 4/5 2/3 4/5 5

5 4/5 4 5 5

10 3/4 3/4 4/5 4/5

30 4 4 5 5

50 3/4 3 4/5 5

Red 150

0 4/5 2 4/5 5

5 4/5 3/4 4/5 5

10 4 4 4/5 4/5

30 4 4 4/5 5

50 3 3 5 5

Blue 10

0 4/5 3 5 5

5 4/5 4/5 4/5 5

10 5 4/5 4/5 5

30 4 4/5 5 5

50 3/4 4 5 5

Blue 100

0 4/5 2/3 4/5 5

5 4/5 3 4/5 5

10 4/5 3/4 4/5 4/5

30 4/5 4 4/5 5

50 3 2/3 4 4/5

Blue 150

0 4/5 2 4/5 5

5 4 3/4 4/5 4/5

10 4 3 4/5 5

30 4 3/4 4/5 5

50 3 2 4 4/5


149

Table 6.3 Effect of varying FC3548 concentration on the fastness performance of red


Table 6.4 Effect of FC3548 concentration on the Martindale Flat Abrasion

performance of pigment dyed cotton fabrics

Formulation Conc.

g/L

FC3548

g/L



Red 10

0 4/5 3/4 5 5

5 4/5 4/5 5 5

10 4/5 4/5 4/5 5

30 4/5 4/5 5 5

50 4/5 4/5 5 5

Red 100

0 4/5 2/3 4/5 5

5 4/5 4 4/5 4/5

10 4/5 4 4/5 4/5

30 4/5 4/5 4/5 5

50 4 4 4/5 4/5

Red 150

0 4/5 2 4/5 5

5 4/5 3/4 4/5 4/5

10 4/5 3/4 4/5 4/5

30 4/5 3/4 4/5 5

50 4/5 3 4/5 4/5

Formulation Conc.

g/L

FC3548

g/L

Rubs

Incorporation Aftertreatment

Red 10

0 13500

5 11000 14500

10 12000 13500

30 8000 9000

50 8500 9000

Red 100

0 16500

5 11000 10500

10 9000 9000

30 9250 9000

50 10000 11000

Red 150

0 17850

5 10500 10000

10 12000 11000

30 10000 10000

50 8000 8000


150

Figure 6.1 Effect of varying FC3548 concentration on the colour strength of

increasing concentrations of pigment formulation applied to cotton fabric

Figure 6.2 Effect of varying FC3548 concentration on the colour strength of pigment

dyed cotton fabrics


151

(a) Dyed cotton (b) Dry-rubbed (c) Wet-rubbed


formulation concentration of 10g/L











152














153














154

6.3.2 Shield F-01 with Shield extender FCD

6.3.2.1 Treatments on Cotton

Table 6.5 shows the comparative fastness results of samples after-treated by F-01

and the control fabrics where the beneficial effects of the fluorocarbon are obvious

on the fabric’s wet rub fastness. However, increasing F-01 concentration does not

always improve wet rub fastness and when the F-01 concentration reached 60g/L,

rub fastness decreased, particularly for dark colours (blue). Even so, the wet rub

fastness was still better than the control fabrics. Although the fastness of the 20g/L

F-01 treated fabric was slightly lower than those of 40g/L samples for heavy shades,

20g/L probably still offers the best choice for application conditions due to the

consideration of cost.

The effect of the F-01 fluorocarbon aftertreatment on the fabric colour strength is

illustrated in Figure 6.15 and it is evident that in general the K/S value is marginally

increased. The colour difference may be a result of F-01 and extender surface film

altering the light interface interaction or less likely non-uniformity in application

during pigment dyeing.

The water and oil repellency of the pigment dyed fabrics treated with F-01 are

presented in Table 6.6 and indicate the water repellency remains fixed at W5, while

oil repellency has improved from OF at 20g/L to 3 at 60g/L. Nevertheless the

repellency performance is not particularly good and maybe related to the softener in

Matrix OSD.

Figures 6.16-6.24 show SEM micrographs of red-dyed fabrics aftertreated with F-01

at increasing concentrations. The micrographs indicate the wet-rubbed areas are

damaged more than dry-rubbed areas and the F-01 has a significant effect on the


155

visual abrasion damage with the rubbed damage less and the surface is smoother,

especially for wet rub fastness. This may be caused by the F-01 repellent finish

overlayer protecting the surface interface.

Table 6.5 Effect of varying F-01 concentration on the fastness of pigment dyed cotton

fabrics

Formulation Conc. g/L

F-01 g/L



Yellow 10

0 5 4 5 5

20 4/5 4/5 5 5

40 4/5 4/5 5 5

60 4/5 4/5 5 5

Yellow 100

0 5 2/3 5 5

20 4/5 4/5 5 5

40 4 4/5 5 5

60 4/5 4/5 5 5

Yellow 150

0 4/5 2/3 4/5 5

20 4/5 4 5 5

40 4/5 4/5 4/5 5

60 4/5 4 5 5

Red 10

0 4/5 3/4 5 5

20 4/5 4/5 5 5

40 4/5 4/5 5 5

60 4/5 4/5 5 5

Red 100

0 4/5 2/3 4/5 5

20 4/5 4 5 5

40 4/5 4/5 5 5

60 4/5 4 5 5

Red 150

0 4/5 2 4/5 5

20 4/5 4/5 4/5 5

40 4 4/5 5 5

60 4 4 5 5

Blue 10

0 4/5 3 5 5

20 4/5 4/5 4/5 5

40 4/5 4/5 5 5

60 4/5 4/5 5 5

Blue 100

0 4/5 2/3 4/5 5

20 4/5 4 4/5 5

40 4 4 5 5

60 4/5 3/4 5 5

Blue 150

0 4/5 2 4/5 5

20 4/5 4 4/5 5

40 4/5 4/5 5 5

60 4/5 3 5 5


156

Table 6.6 Effect of varying F-01 concentration on the water and oil repellency of

pigment dyed cotton fabrics


dyed cotton fabrics

Formulation Conc. g/L F-01 g/L Water repellency Oil repellency

Yellow 10

20

W5 OF

Yellow 100 W5 OF

Yellow 150 W5 OF

Red 10

40

W5 2

Red 100 W5 2

Red 150 W5 2

Blue 10

60

W5 3

Blue 100 W5 3

Blue 150 W5 3


157














158














159




6.3.2.2 Fluorocarbon Treatments on Polycotton Fabric

Polyester/cotton (Polycotton) fabric is the most common textile fabric blend and was

evaluated in this study in order to determine if the pigment dyeing system

functioned similarly on blends and whether fluorocarbon treatment could have a

similarly beneficial effect on blend performance. The fastness results of the

polycotton control fabric (F-01 concentration is 0g/L) and F-01 treated samples are

presented in Table 6.7, and indicated the performance of the control polycotton

fabrics are better than those observed for 100% cotton fabric. The wet rub fastness

was higher, while the dry rub fastness and wash fastness were maintained at an

excellent level. After the pigment dyed polycotton samples were treated with F-01,

the wet rub fastness significantly improved, the best application level being 20g/L.

Further as shown in Figure 6.25, it was apparent that a similar improvement in K/S

was observed, especially for blue-dyed samples, with increasing fluorocarbon

application.


160

Table 6.7 Effect of varying F-01 concentration on the fastness of pigment dyed

polycotton fabrics

Formulation Conc.

g/L

F-01

g/L



Yellow 10

0 4/5 4/5 5 5

20 4/5 4/5 5 5

40 4/5 4/5 5 5

60 4/5 5 5 5

Yellow 100

0 4/5 4/5 5 5

20 4/5 4/5 5 5

40 4/5 4/5 5 5

60 4/5 4/5 5 5

Yellow 150

0 4/5 4/5 5 5

20 4/5 4/5 5 5

40 4 4/5 5 5

60 4/5 4/5 5 5

Red 10

0 4/5 4/5 5 5

20 4/5 4/5 5 5

40 4/5 4/5 5 5

60 4/5 4/5 5 5

Red 100

0 4/5 3 5 5

20 4/5 4 5 5

40 4 4/5 5 5

60 4 4/5 5 5

Red 150

0 4/5 3/4 5 5

20 4/5 4 5 5

40 4/5 4/5 5 5

60 4/5 4 5 5

Blue 10

0 4/5 4 5 5

20 4/5 4/5 5 5

40 4/5 4/5 5 5

60 4/5 4/5 5 5

Blue 100

0 4 3 4/5 5

20 4/5 4 5 5

40 4 4/5 5 5

60 4 4 4/5 5

Blue 150

0 4 3/4 4/5 5

20 4/5 4/5 5 5

40 4 4/5 5 5

60 4 4 4/5 5


161


dyed polycotton fabrics

6.3.3 Shield FRN6

Table 6.8 presents the fastness results of fabrics treated with Shield-FRN6 and the

control fabrics. The benefits of FRN6 after-treatment are clear on wet rub fastness,

however, increasing the FRN6 concentration did not increase the fastness further.

The optimal concentration therefore appears to be ~30g/L. The colour strength of the

fabrics treated by FRN6 appeared to be little different to the control fabrics, Figure

6.26.

As can be seen from Table 6.9, the flat abrasion resistance of the pigment dyed

fabrics was reduced after the application of FRN6 probably due to the reducing

fibre/fabric coating cohesion. Although increasing FRN6 concentration improved

abrasion resistance, the number of rub cycles to failure are still lower than these of


162

control fabrics.

Figures 6.27-6.29 present the selected KES-F results of the mechanical properties of

the blue pigment-dyed fabrics treated by FRN6. The results indicate that increasing

the pigment binder concentration from 10g/L to 150g/L increased the fabric rigidity

and that the subsequent fluorocarbon addition further increased fabric stiffness.

Table 6.10 illustrates the water and oil repellency results of the pigment dyed fabrics

after-treated by FRN6 fluorocarbon. It is clear that the repellency property is only

related to the FRN6 concentration, not the pigment formulation concentration. The

observed repellency performance is similar to F-01 treated fabrics in Section 6.3.2.1.

Water repellency is at the W5 level at all concentrations, while oil repellency is just

1 to 2 similar to the F-01 treatment. These repellency results are not adequate, and

may be caused by the softener in Matrix OSD binder.

Figures 6.30-6.38 show SEM micrographs of the blue-pigment dyed fabrics

after-treated by FRN6 at different concentrations and indicated the wet-rubbed areas

are more disrupted than the dry-rubbed areas. Compared with the images of the

control samples, the rubbing damage in the fluorocarbon treated material is lower

and the surface is smoother, this is especially obvious in the wet-rubbed fabric

micrograph. However, the level of damage increased with the increase of FRN6

concentration, suggesting the 30g/L application level was the best in terms of the

fastness performance. The FRN6 protected the fabric surface probably due to

lubrication of the interface.


163

Table 6.8 Effect of varying FRN6 concentration on the fastness performance of


Formulation Conc.

g/L

F6

g/L



Yellow 10

0 5 4 5 5

30 4/5 4/5 5 5

45 4/5 4/5 5 5

60 4/5 4/5 5 5

Yellow 100

0 5 2/3 5 5

30 4/5 4 5 5

45 4/5 4 5 5

60 4/5 4/5 5 5

Yellow 150

0 4/5 2/3 4/5 5

30 4/5 4/5 5 5

45 4/5 4 4/5 5

60 4/5 3/4 5 5

Red 10

0 4/5 3/4 5 5

30 4/5 4/5 5 5

45 4/5 4/5 5 5

60 4/5 4/5 5 5

Red 100

0 4/5 2/3 4/5 5

30 4/5 3/4 4/5 5

45 4/5 4 4/5 5

60 4/5 3 5 5

Red 150

0 4/5 2 4/5 5

30 4/5 4 5 5

45 4/5 3/4 4/5 5

60 4/5 3/4 5 5

Blue 10

0 4/5 3 5 5

30 4/5 4/5 5 5

45 4/5 4/5 5 5

60 4/5 4 5 5

Blue 100

0 4/5 2/3 4/5 5

30 4/5 4 5 5

45 4/5 3/4 4/5 5

60 4/5 3 5 5

Blue 150

0 4/5 2 4/5 4/5

30 4/5 3/4 5 5

45 4 3 4/5 5

60 4/5 2/3 5 5


164

Table 6.9 Effect of varying FRN6 concentration on the flat abrasion of pigment dyed

cotton fabric

Table 6.10 Effect of varying FRN6 concentration on the water and oil repellency of

red pigment dyed cotton fabric

Formulation Conc. g/L F6 g/L Rubs

Red 10

0 13500

30 10250

45 10250

60 12500

Red 100

0 16500

30 12000

45 14500

60 15500

Red 150

0 17850

30 15000

45 15500

60 15750

Formulation Con. g/L F6 g/L Water repellency Oil repellency

10

30

W5 1

100 W5 1

150 W5 1

10

45

W5 2

100 W5 2

150 W5 2

10

60

W5 2

100 W5 2

150 W5 2


165

Figure 6.26 Effect of varying FRN6 concentration on the colour strength of pigment

dyed cotton fabric

Figure 6.27 Effect of varying FRN6 concentration on the bending stiffness of red



166

Figure 6.28 Effect of varying FRN6 concentration on the shear stiffness of red


Figure 6.29 Effect of varying FRN6 concentration on the shear hysteresis, 2HG5, of

red pigment dyed cotton fabric


167














168














169




6.3.4 Effect of P2i dry plasma polymerisation treatments on pigment

dyed fabric fastness and liquid repellency performance

The P2i plasma polymerisation treatment improved the fabric fastness properties,

but not as significantly as samples treated by F-01 and FRN6, Table 6.11. In addition

the standard process, designated number 3, decreased the dry rub fastness,

particularly for medium and dark shades. Process 2 achieved better results than

process 1, but the differences were not large. The dry plasma polymerisation will

only deposit a 100-200nm thick layer while aqueous treatment will deposit a much

thicker layer so aiding in the observed wet and dry fastness improvements.

As shown in Figure 6.39, the colour strength almost stays at the same level as the

control samples.

Water and oil repellency results are presented in Table 6.12 and indicate before P2i

treatment, fabric water and oil repellency are all failed, however post-P2i treatment

repellency was imparted. Process 3 showed a greater effect than the other two

processes for water repellency while oil repellency levels are the same. After ISO

CO6 washing, both water and oil repellency were decreased and for water repellency,

the initial advantages of process 3 were not observed anymore. The reason for this

behaviour is not certain. After heat pressing, water repellency still was W5 but the

oil repellency recovered to the original value of 7, except for process 1 which


170

increased but not to the original value. Overall the water and oil repellency of the

P2i treatments are better than those of the fabrics treated by the aqueous F-01 and F6

treatments.

In contrast to the aqueous fluorocarbon treatments the fabric handle properties of P2i

treated fabrics, as determined by the KES-F analysis indicated the fabric rigidity was

reduced, Figures 6.40-6.42. The reduction in stiffness was due most likely to the

lubricating effect of the thin fluorocarbon surface layer.

Figures 6.43-6.51 illustrate the SEM analyses of the blue pigment-dyed fabrics

after-treated by P2i under different conditions. No obvious surface film was

apparent on the cotton fibres but it is evident that the wet-rubbed areas were more

disrupted than the dry-rubbed areas. Comparison between the control samples, and

the P2i treated materials indicated relatively little difference in the abrasion

behaviour. In addition, in comparison with the aqueous fluorocarbon treatments, the

rubbing damage was more obvious which correlated with the poorer observed rub

fastness.

Table 6.11 Effect of varying P2i treatment on the fastness of blue pigment dyed cotton

fabric

Formulation conc.

g/L P2i process



10

Control 4/5 3 5 5

1 4/5 4 5 5

2 4/5 4 5 5

3 4/5 4 5 5

100

Control 4/5 2/3 4/5 5

1 4/5 3 4/5 5

2 4/5 3/4 4/5 5

3 3 3/4 4/5 5

150

Control 4/5 2 4/5 5

1 4/5 2/3 4/5 5

2 4/5 3 4/5 5

3 3/4 3/4 4/5 5


171

Table 6.12 Effect of varying P2i treatment on the water and oil repellency of blue


a- P2i treated samples b- P2i treated/washed samples c- P2i treated/washed/heat pressed samples

*Heat pressed for 20s, washed by the ISO CO6 method

Figure 6.39 Effect of varying P2i treatment on the colour strength of blue pigment

dyed cotton fabric

Formulation

conc. g/L

P2i

process

Water repellency Oil repellency

a b c a b c

10

Control WF OF

1 W7 W5 W5 7 3 7

2 W9 W5 W5 7 4 7

3 W10 W6 W5 7 6 7

100

Control WF OF

1 W7 W5 W5 7 3 6

2 W8 W5 W5 7 4 7

3 W10 W5 W5 7 4 7

150

Control WF OF

1 W6 W5 W5 7 3 5

2 W7 W5 W5 7 4 7

3 W8 W5 W5 7 4 7


172

Figure 6.40 Effect of varying P2i treatment on the bending stiffness blue pigment

dyed cotton fabric

Figure 6.41 Effect of varying P2i treatment on the shear stiffness of blue pigment

dyed cotton fabric


173

Figure 6.42 Effect of varying P2i treatment on the shear hysteresis, 2HG5, of blue









174



formulation concentration 10g/L











175










6.3.5 Effect of Oleophobol on repellency performance

Examination of the performance of the Oleophobol treated fabrics indicated there is

relatively little difference between the two application methods for the fluorocarbons,

Tables 6.13-6.14 and Figure 6.52. Nevertheless it was apparent that there was a

small decrease in the dry rub fastness with increasing Oleophobol concentration

application, whilst the wet rub fastness increased at the 40g/L application level.


176

Wash fastness remained excellent.

Interestingly there were some beneficial effects in colour strength with fluorocarbon

addition, Figure 6.52, although the improvement was reduced at 60g/L.

Table 6.14 indicated the water repellency was W5 for both pre-mixing and

after-treatment methods, while oil repellency is better when Oleophobol was mixed

into the pigment dyeing system possibly due to better orientation at the fibre surface.

In the wider context the repellency results were almost the same as those of F-01

and FRN6 treatments.

Table 6.13 Effect of varying Oleophobol concentration on the fastness of blue


Treatment Formulation

Conc. g/L

Oleophobol

Conc. g/L


Dry Wet Colour

Change Staining

Pre

-mixing

Blue 10

0 4/5 3 5 5

40 4/5 4 5 5

60 4 4/5 5 5

Blue 100

0 4/5 2/3 4/5 5

40 4 4 5 5

60 3/4 3/4 5 5

Blue 150

0 4/5 2 4/5 4/5

40 3/4 4/5 5 5

60 4 4 5 5

After

-treating

Blue 10

0 4/5 3 5 5

40 4 4/5 5 5

60 4/5 4/5 5 5

Blue 100

0 4/5 2/3 4/5 5

40 4 4 5 5

60 3/4 4 5 5

Blue 150

0 4/5 2 4/5 4/5

40 4 4 5 5

60 3/4 4 5 5


177

Table 6.14 Effect of varying Oleophobol concentration on the water and oil repellency

of blue pigment dyed cotton fabric

Treatment Formulation

Con. g/L

Oleophobol

Con. g/L

Water

Repellency

Oil

Repellency

Pre

-mixing

Blue 10

0 WF OF

40 W5 4

60 W5 4

Blue 100

0 WF OF

40 W5 4

60 W5 4

Blue 150

0 WF OF

40 W5 4

60 W5 4

After

-treating

Blue 10

0 WF OF

40 W5 2

60 W5 2

Blue 100

0 WF OF

40 W5 2

60 W5 2

Blue 150

0 WF OF

40 W5 2

60 W5 2

Figure 6.52 Effect of varying Oleophobol concentration on the colour strength of

blue pigment dyed cotton fabric (λmax=610nm)


178

6.3.6 Water/Oil Repellency Performance

6.3.6.1 Fluorocarbon Application to Undyed Cotton Fabric

Tables 6.15 and 6.16 show the results of the undyed cotton fabric treated with

fluorocarbons: Shield F-01 with Shield extender FCD; Shield FRN6; Oleophobol

7713 with Hydrophobol XAN. Surprisingly the ISO CO6 washing process had no

effect on water repellency, while it does reduce the oil repellency. However, oil

repellency is mainly recovered after heat pressing due to molecular re-orientation.

In general, the application of surface fluorocarbons improved flat abrasion resistance,

although the increased application levels tend to result in lesser improvements. For

F-01 and FRN6 treatment, the rub cycles to failure decreased with the increasing

fluorocarbon concentration, while in contrast the effect of increasing Oleophobol

concentration was higher abrasion resistance. Comparing the FRN6 results with

those following pigment dyeing, indicated non-pigment dyed materials had better

abrasion resistance, possibly due to better lubrication at the cellulosic interface.

Table 6.15 Water and oil repellency of cotton fabric treated with fluorocarbons and

subsequently washed and heat pressed

Fluorocarbon Concentration

g/L

Water repellency Oil repellency

a b c a b c

F-01

20 W5 W5 W5 2 OF 2

40 W5 W5 W5 4 OF 3

60 W5 W5 W5 4 OF 3

FRN6

30 W5 W5 W5 2 OF 2

45 W5 W5 W5 2 1 2

60 W5 W5 W5 3 OF 2

Oleophobol 40 W5 W5 W5 3 OF 3

60 W5 W5 W5 4 1 4

a- Fluorocarbon treated

b- Fluorocarbon treated and washed

c- Fluorocarbon treated, washed and heat pressed

OF- No oil repellency


179

Table 6.16 Abrasion resistance on cotton fabric treated by fluorocarbons

Fluorocarbon Concentration

g/L Rubs

Untreated cotton 0 14000

F-01

20 21500

40 19000

60 17000

FRN6

30 19000

45 16000

60 16000

Oleophobol 40 20000

60 24250

6.3.6.2 Matrix OSD System with No Softener

The comparison of the water and oil repellency of the red pigment dyed fabrics

treated by fluorocarbons, Table 6.17, indicated there was no repellency improvement

with the binder containing no silicone softener. Indeed the fabric water repellency

was relatively lower than the pigment dyeing system including softener.


180

Table 6.17 Water and oil repellency of red pigment dyed cotton treated with F-01 and

FRN6 fluorocarbon finishes

Fluorocarbon

Conc. g/L

Formulation Conc.

g/L Water repellency Oil repellency

F-01

20

10 4 1

100 4 1

150 4 1

40

10 4 2

100 4 2

150 4 2

60

10 4 2

100 4 2

150 4 2

FRN6

30

10 4 2

100 4 2

150 4 2

45

10 4 2

100 4 2

150 4 2

60

10 4 3

100 4 3

150 4 3

6.3.6.3 Rucoguard LAD and Oleophobol 7713

In order to establish the effect of incorporating the softener into the Matrix OSD and

identify possible alternative better application conditions to improve the repellency

of the pigment dyeing system, exhaustion and padding application conditions were

examined for fluorocarbon finishes, Table 6.18. From the results it was apparent that

the exhaustion method was better for water and oil repellency performance. Though

it is uncertain why the fabric’s oil repellency was so poor for the padding application.

The Matrix OSD binder with softener offered decreased repellency properties.


181

Table 6.18 Water and oil repellency of plain untreated cotton and red pigment dyed

cotton treated by Rucoguard LAD and Oleophobol 7713 by exhaustion and padding

applications

Treatment methods Treated fabrics Water

repellency Oil repellency

Exhausting

Plain untreated cotton W8 5

R100* (with softener) W4 3

R100* (without softener) W8 5

Padding

Plain untreated cotton W0 OF

R100* (with softener) W4 OF

R100* (without softener) W4 OF

*R100 – Samples dyed by 100g/L red pigment dyeing formulation.

6.4 Conclusions

In general the effect of applying fluorocarbons to the pigment dyed fabrics had a

beneficial effect on wash fastness and wet rub fastness, while dry rub fastness was

marginally reduced at higher application levels. Comparing the fastness results on

samples treated by different fluorocarbons, the best conditions were found when the

dyed samples were after-treated by Shield F-01 with Shield extender FCD at 20g/L.

At this F-01 concentration, rub fastness and wash fastness were all at an excellent

level, above rating 4. Similarly with the polycotton fabric the benefits of F-01

treatment were apparent, particularly at the 20g/L application level. Although the dry

P2i plasma treatment cannot achieve the fastness results as the aqueous fluorocarbon

treatments, it still imparted improved water/oil repellency and fabric handle.

SEM analysis of the fabric damage due to the wet and dry rubbing indicated wet

abrasion was more damaging but that there was less damage in the samples treated

with the F-01 fluorocarbon.

When the fluorocarbon treatment was combined with the pigment dyeing systems,


182

there was a deleterious effect on abrasion resistance and a reduced performance was

observed. However, in contrast when fluorocarbon was directly applied onto undyed

cotton fabrics, the abrasion resistance was improved, the Oleophobol treatment

giving the best result at the concentration of 60g/L.

Water and oil repellency of treated undyed cotton fabrics were the same as those on

coloured cotton. The only experiment which shows there was adverse effect related

to softener in the binder was the exhaustion application method with Oleophobol

7713 and Rucoguard LAD.

6.5 References

1. Celik, N., Icoglu, H. I., and Erdal, P., Effect of the Particle Size of

Fluorocarbon-based Finishing Agents on Fastness and Color Properties of

100% Cotton Knitted Fabric, Journal of the Textile Institute, 2011, 102(6):

p.483-490.

2. Grajeck, E. J. and Petersen, W. H., Oil and Water Repellent Fluorochemical

Finishes for Cotton, Textile Research Journal, 1962, 32(4): p.320-331.

3. Rijke, A. M., The Liquid Repellency of a Number of Fluorochemical

Finished Cotton Fabrics, Journal of Colloid Science, 1965, 20(3): p.205-216.

4. Vaswani, S., Koskinen, J., and Hess, D. W., Surface Modification of Paper

and Cellulose by Plasma-assisted Deposition of Fluorocarbon Films. Surface

& Coatings Technology, 2005, 195(2-3): p.121-129.

5. Von Gradowski, M., ToF-SIMS Characterisation of Ultra-thin Fluorinated

Carbon Plasma Polymer Films, Surface & Coatings Technology, 2005,

200(1-4): p.334-340.

Chapter 7 Investigation into the Effect of Plasma Treatment on Matrix OSD Treated Cotton Fabric

183


Plasma Treatment on Matrix OSD Treated

Cotton Fabric

7.1 Introduction

Plasma techniques are attractive for several reasons in that they allow selective

modification of the substrate surface and the hydrophilic/hydrophobic nature of the

surface can be engineered by selecting the appropriate gas [1]. In modern textile

industry, selective removal of surface hydrophobic layers, enhancement of the

hydrophilicity and production of cotton with improved bleachability and dyeability

is increasingly important. Plasma-related techniques have been gradually used more

owing to their low impact on the environment and targeted surface modification.

Plasma research has also been focused on improving wettability, water repellency,

anti-soiling, soil release, printing, dyeing and some other finishing treatments of

textile fibres and fabrics [2-5]. In most of these studies, low-pressure plasma has

been mainly considered, but the plasma operation at low pressure is relatively

expensive, slower and can create technical difficulties. In recent years, treatments

using atmospheric pressure plasma jet were developed in order to offer process

flexibility and to create homogeneous plasma at low temperature [6-8].

In this chapter, helium, oxygen, nitrogen and argon were used as the plasma treating

gases. The samples treated were under the atmospheric pressure before and after

pigment dyeing. There is currently little research on the use of plasma system on

pigment dyeing systems. In this study, the interaction between the pigment dyeing

system and plasma treatments was studied.


184

7.2 Experimental work

7.2.1 Materials

Fabrics 100% bleached plain cotton fabric, 191.5g/m2, was supplied by

Whaleys, Bradford, UK.





Switzerland.


7.2.2 Dyeing System

The modified Matrix OSD system discussed in 4.2.4 was used as the pigment dyeing

system.

7.2.3 Plasma Treatment

7.2.3.1 Plasma pre-treatment

The undyed and pigment dyed cotton fabrics were treated under atmospheric

pressure using three different plasma gases at Enercon using a Plasma4™

atmospheric plasma surface treatment system:

a. 100% Helium;

b. 80% Helium with 20% oxygen, O2;

c. 80% Helium with 20% nitrogen, N2.

During the treatment, the line speed was 10m/min and power level was 1kW. After

plasma treating, the fabrics were blue- pigment- dyed following standard


185

procedures.

7.2.3.2 Plasma after-treatment

The cotton fabrics were pigment-dyed first and then divided into two parts. Half of

the fabrics were cured after the drying process and another half had no heat curing

procedure. These fabrics were then plasma treated under six different conditions on

both sides of cotton fabrics. The treatment conditions are illustrated in Table 7.1.

After plasma treatment, the uncured fabrics were cured under the normal conditions

for pigment dyeing system.

Table 7.1 Plasma treatment conditions

a b c d e f

Gas N2 Ar N2 Ar N2 Ar

Line

speed

(m/min)

10 10 10 10 7 7

Power

level

(kW)

0.5 0.5 1 1 1.1 1.1

Watt

density

90W/m2/

min

90W/m2/

min

180W/m2/

min

180W/m2/

min

285W/m2/

min

285W/m2/

min


7.3.1 Effect of Pre-treatment

The fastness results of the samples pre-treated with He/O2/N2 gases and the control

fabrics are shown in Table 7.2. Due to this plasma process preferentially only

treating one side of the cotton fabric, the rub fastness was tested for both sides: the

face and the reverse/back. Examination of the results indicated the dry rub fastness

decreased while the wet rub fastness was improved, although both changes were just

half scale. Interestingly, the back rub fastness was worse than the face side. In


186

addition after washing, the colour changed more after plasma treatment, but was still

not a significant change.

As can be seen in Figure 7.1, the colour strength was improved after treatment with

all plasma gases, although there was no clear trend.

Table 7.2 Effect of plasma pre-treatment on colour fastness

Formulation

Conc. g/L Gas


Dry Wet Colour

Change Staining

face back face back

Blue10

Reference 4/5 3 4/5 5

He 4/5 4 3 2/3 4/5 5

He+O2 4 4 3 3 4/5 5

He+N2 4/5 4/5 4 4 4/5 5

Blue100

Reference 4/5 2/3 4/5 5

He 4/5 4 3 2/3 4 5

He+O2 4 3/4 2/3 2/3 4 5

He+N2 4 3/4 3 2/3 4 5

Blue150

Reference 4/5 2 4/5 5

He 4 3/4 3 3 4 5

He+O2 4 3/4 2/3 2/3 4 5

He+N2 4 4 2/3 2/3 4 5


187

Figure 7.1 Effect of plasma pre-treatment on colour strength (λmax=610nm)

7.3.2 Effect of Plasma After-treatment on the Fastness of Pigment

Dyed Fabrics

Tables 7.3-7.5 present the fastness results of heat cured pigment dyed fabrics with

plasma gas aftertreatment. It is evident that plasma treatment maintained the

excellent wash fastness and rub fastness was also either maintained or improved. In

particular the wet rub fastness was significantly improved. The plasma treatments

under the conditions of 0.5kW Ar, 1.0kW Ar and 1.0kW N2 achieved almost the

same effect but the 0.5kW Ar conditions were selected as the best condition based

on cost.

Further plasma after-treatments examined the effect of plasma treatment before the

final heat curing procedure of pigment dyeing, Tables 7.6-7.8. Similar to the

previous analysis the wash fastness and dry rub fastness remained almost unchanged


188

after plasma treatment. In contrast the wet rub fastness again was improved with the

1.0kW N2 plasma atmosphere offering the best treatment conditions. Comparing the

results of curing before plasma treatment and afterwards, the treatment with 1kW N2

(curing after plasma) achieved the better results.

The effect of plasma treatments on polymers is to create free radicals which can

either crosslink or react with oxygen or other reactive gases present [9, 10]. In this

study the effect of the argon and nitrogen plasma treatments was to increase rub

fastness which is probably due to creating a crosslinked outer surface layer that is

more resistant to abrasion and improves colour fastness. Similarly in plasma

treatment before heat curing the effect again was to increase rub fastness which is

probably due to creating a crosslinked outer surface layer that is more resistant to

abrasion and improves colour fastness. Previous studies examining the effect of

plasma processing on DMDHEU/acrylic acid treated cotton was to increase

crosslinking and improve crease recovery performance [11].


189

Table 7.3 Effect of plasma after-treatment on heat cured yellow pigment dyed fabric

fastness

Formulation

Conc. g/L Plasma treatment



Yellow 10

None 5 4 5 5

0.5kW Ar 5 4/5 5 5

0.5kW N2 4/5 4/5 5 5

1.0kW Ar 5 4/5 5 5

1.0kW N2 4/5 4/5 5 5

1.1kW Ar 4/5 4/5 5 5

1.1kW N2 4/5 4/5 5 5

Yellow 100

None 5 2/3 5 5

0.5kW Ar 4/5 3/4 4/5 5

0.5kW N2 4/5 3/4 5 5

1.0kW Ar 5 3/4 5 5

1.0kW N2 4/5 3/4 4/5 5

1.1kW Ar 4/5 3 5 5

1.1kW N2 4/5 3/4 5 5

Yellow 150

None 4/5 2/3 4/5 5

0.5kW Ar 4/5 3 4/5 5

0.5kW N2 4/5 2/3 5 5

1.0kW Ar 4/5 3/4 4/5 4/5

1.0kW N2 4/5 3/4 4/5 5

1.1kW Ar 4/5 3 5 5

1.1kW N2 4/5 2/3 5 5


190

Table 7.4 Effect of plasma after-treatment on heat cured red pigment dyed fabric

fastness

Formulation




Red 10

None 4/5 3/4 5 5

0.5kW Ar 5 4/5 5 5

0.5kW N2 4/5 4/5 5 5

1.0kW Ar 5 4 5 5

1.0kW N2 4/5 4 5 5

1.1kW Ar 4/5 4/5 5 5

1.1kW N2 4/5 4/5 5 5

Red 100

None 4/5 2/3 4/5 5

0.5kW Ar 4/5 3/4 4/5 5

0.5kW N2 4/5 3 4/5 5

1.0kW Ar 5 3 4/5 4/5

1.0kW N2 4/5 3 4/5 4/5

1.1kW Ar 4/5 2/3 4/5 4/5

1.1kW N2 4/5 3 4/5 5

Red 150

None 4/5 2 4/5 5

0.5kW Ar 4/5 3 4/5 5

0.5kW N2 4/5 3 4/5 5

1.0kW Ar 4/5 3 4/5 4/5

1.0kW N2 4/5 3 4/5 4/5

1.1kW Ar 4/5 2/3 4/5 4/5

1.1kW N2 4/5 3 4/5 5


191

Table 7.5 Effect of plasma after-treatment on heat cured blue pigment dyed fabric

fastness

Formulation




Blue 10

None 4/5 3 5 5

0.5kW Ar 4/5 4/5 5 5

0.5kW N2 4/5 4 5 5

1.0kW Ar 4/5 4 5 5

1.0kW N2 4/5 4 5 5

1.1kW Ar 4/5 4 5 5

1.1kW N2 4/5 4 5 5

Blue 100

None 4/5 2/3 4/5 5

0.5kW Ar 4/5 3 5 5

0.5kW N2 4/5 2/3 4/5 5

1.0kW Ar 4/5 3/4 4/5 5

1.0kW N2 4/5 3 4/5 4/5

1.1kW Ar 4/5 2/3 4/5 4/5

1.1kW N2 4/5 2/3 4/5 5

Blue 150

None 4/5 2 4/5 4/5

0.5kW Ar 4/5 2/3 4/5 5

0.5kW N2 4 2/3 4/5 5

1.0kW Ar 5 3 4/5 4/5

1.0kW N2 4/5 3 4/5 4/5

1.1kW Ar 4/5 2 4/5 4/5

1.1kW N2 4/5 2/3 4/5 5


192

Table 7.6 Effect of plasma after-treatment on uncured yellow pigment dyed fabric

followed by heat curing, fastness

Formulation




Yellow 10

None 5 4 5 5

0.5kW Ar 4/5 4/5 5 5

0.5kW N2 4/5 4/5 5 5

1.0kW Ar 4/5 4/5 5 5

1.0kW N2 4/5 4/5 5 5

1.1kW Ar 4/5 4/5 5 5

1.1kW N2 4/5 4/5 5 5

Yellow 100

None 5 2/3 5 5

0.5kW Ar 4/5 3/4 5 5

0.5kW N2 4/5 4 5 5

1.0kW Ar 4/5 3 5 5

1.0kW N2 4/5 4 5 5

1.1kW Ar 4/5 4 5 5

1.1kW N2 4/5 3 5 5

Yellow 150

None 4/5 2/3 4/5 5

0.5kW Ar 4/5 3/4 5 5

0.5kW N2 4/5 3/4 5 5

1.0kW Ar 4/5 3/4 5 5

1.0kW N2 4/5 3/4 5 5

1.1kW Ar 4/5 3/4 4/5 5

1.1kW N2 4/5 3 5 5


193

Table 7.7 Effect of plasma after-treatment on uncured red pigment dyed fabric


Formulation




Red 10

None 4/5 3/4 5 5

0.5kW Ar 4/5 4 5 5

0.5kW N2 4/5 4 5 5

1.0kW Ar 4/5 4 5 5

1.0kW N2 4/5 4 5 5

1.1kW Ar 4/5 4 4/5 5

1.1kW N2 4/5 4 5 5

Red 100

None 4/5 2/3 4/5 5

0.5kW Ar 4/5 3 4/5 4/5

0.5kW N2 4/5 3 5 4/5

1.0kW Ar 4/5 3 5 5

1.0kW N2 4/5 3/4 5 5

1.1kW Ar 4/5 3/4 4/5 5

1.1kW N2 4/5 2/3 5 4/5

Red 150

None 4/5 2 4/5 5

0.5kW Ar 4/5 3/4 4/5 4/5

0.5kW N2 4/5 3 4/5 4/5

1.0kW Ar 4/5 3 4/5 4/5

1.0kW N2 4/5 3/4 4/5 5

1.1kW Ar 4/5 3 4/5 5

1.1kW N2 4/5 2/3 4/5 4/5


194

Table 7.8 Effect of plasma after-treatment on uncured blue pigment dyed fabric


Formulation




Blue 10

None 4/5 3 5 5

0.5kW Ar 4/5 4 5 5

0.5kW N2 4/5 4 4/5 5

1.0kW Ar 4/5 4 5 5

1.0kW N2 4/5 4 5 5

1.1kW Ar 4/5 4 5 5

1.1kW N2 4/5 4 4/5 5

Blue 100

None 4/5 2/3 4/5 5

0.5kW Ar 4/5 3/4 4/5 5

0.5kW N2 4/5 3/4 4/5 5

1.0kW Ar 4/5 3/4 4/5 5

1.0kW N2 4/5 3 4/5 5

1.1kW Ar 4/5 3/4 4/5 5

1.1kW N2 4 2/3 4/5 5

Blue 150

None 4/5 2 4/5 4/5

0.5kW Ar 4/5 2/3 4/5 5

0.5kW N2 4/5 2/3 4/5 5

1.0kW Ar 4/5 3/4 4/5 4/5

1.0kW N2 4/5 3/4 4/5 5

1.1kW Ar 4/5 3 4/5 5

1.1kW N2 4/5 2/3 4/5 5

7.4 Conclusions

Plasma pre-treatment prior to pigment dyeing has a marginal benefit on fastness

properties, and to some extent slightly decreased dry rub fastness. However, colour

strength was improved under all gas conditions. Mixed gas treatments (He & O2 and

He & N2) are better than the single gas treatment (He).

Plasma after-treatments, both Ar and N2 atmospheres, improved the fastness,

particularly wet fastness, when the curing procedure was applied before plasma

treatment.


195

Compared with the P2i treatment, Chapter 6, the fastness results were almost the

same, no matter which gaseous system was applied. However, the P2i treatment

showed better colour strength and fabric properties. Accordingly this research

direction should be an interesting area for the future work of plasma treatment even

though the atmospheric plasma treatment offers more opportunity for continuous

treatment.

7.5 References

1. Zeng, F., Textiles., Investigation into the Colouration of Polypropylene,

UMIST PhD Thesis, 2002.


Plasma Polymerisation Methods, Coloration Technology, 2002, 118(3):

p.100-103.

3. Okuno, T., Yasuda, T., and Yasuda, H., Effect of Crystallinity of PET and

Nylon-66 Fibers on Plasma-etching and Dyeability Characteristics, Textile

Research Journal, 1992, 62(8): p.474-480.

4. Sarmadi, A. M. and Kwon, Y. A., Improved Water Repellency and Surface

Dyeing of Polyester Fabrics by Plasma Treatment, Textile Chemist and

Colorist, 1993, 25(12): p.33-40.

5. Wakida, T., Surface Characteristics of Wool and Poly (ethylene terephthalate)

Fabrics and Film Treated with Low-Temperature Plasma Under Atmospheric

Pressure, Textile Research Journal, 1993, 63(8): p.433-438.

6. Tian, L. Q., Helium/oxygen Atmospheric Pressure Plasma Jet Treatment for

Hydrophilicity Improvement of Grey Cotton Knitted Fabric, Applied Surface

Science, 2011, 257(16): p.7113-7118.

7. Peng, S., Influence of Argon/oxygen Atmospheric Dielectric Barrier

Discharge Treatment on Desizing and Scouring of Poly (vinyl alcohol) on

Cotton Fabrics, Applied Surface Science, 2009, 255(23): p.9458-9462.


196

8. Mitchell, R., Carr, C. M., Parfitt, M., Vickerman, J. C. and Jones, C., Surface

Chemical Analysis of Raw Cotton Fibres and Associated Materials, Cellulose,

2005, 12(6): p.629-639.

9. Sparavigna, A., Plasma Treatment Advantages for Textiles, arXiv:

0801.3727 [physics.pop-ph], 2008.

10. Morent, R., De Geyter, N., Verschuren, J., De Clerck, K., Kiekens, P. and

Leys, C., Surface and Coatings Technology, 2008, 202: p.3427-3449.

11. Chen, C. C., Chen, J. C. and Yao, W. H., Argon Plasma Treatment for

Improving the Physical Properties of Crosslinked Cotton Fabrics with

Dimethyloldihydroxyethyleneurea-Acrylic Acid, Textile Research Journal,

2010, 80 (8): p.675-682.

Chapter 8 Surface Analysis

197


8.1 XPS Analysis of Blue Pigment-dyed Cotton Treated

with Fluorocarbons

Since the colour fastness performance of the pigment dyed fabrics appeared to be

strongly influenced by the surface interface the surface sensitive techniques, XPS

and ToF-SIMS were used to characterise the outer region and potentially provide

insight in how to improve the durability of colourant/polymer binder layer.

Examination of the XP spectrum of untreated cotton fabric indicated the presence of

mainly carbon, oxygen and traces of nitrogen, Table 8.1. The C (1s) spectrum of the

untreated cotton, Figure 8.1, shows the presence of a number of carbon species

present in the outer 10nm as indicated by the characteristic binding energies:

285.0eV C-C, C-H;

286.6eV C-OH;

288.0eV C=O; O-C-O;

289.0eV HO-C=O;

If the cotton fibre surface was pure cellulose it would be expected that only two

carbon spectral features would be observed, that is the C-OH and O-C-O species

with relative intensities of 5:1. However it is evident that significant

hydrocarbon-based material, at a binding energy of 285.0eV, and carboxyl species,

at 289.0eV, were present at the fibre surface. In addition the expected C-O and

O-C-O species ratio of 5:1 was not apparent suggesting the peak intensity at

288.0eV has increased due to the presence of C=O species. The scouring and

bleaching of cotton fabric is known to oxidise the fibre surface giving rise to

oxycellulose and previous surface analysis of cotton has reported that not all the

cotton wax was removed from the fibre surface following these wet preparation

processes [1, 2].


198

Application of the Matrix OSD binder with increasing levels of pigment to the

untreated cotton fabric results in an concomitant increase in the N (1s) spectral peak

intensity related to the organic pigment, Table 8.1. Figures 8.1-8.4 present the C (1s)

spectra of the blue pigment dyed cotton fabrics and it is evident at the 10g/L

application level that there is an obvious difference in the C (1s) spectral component

intensities at the 10g/L application level. However at 100 and 150g/L levels the

spectral profile is similar to the original cotton surface composition and probably

reflects the increased level of pigment and its similar elemental composition to the

cotton surface.

The C (1s), O (1s), F (1s) and N (1s) atomic compositions of the blue-dyed fabrics

after-treated with the F-01 and F6 fluorocarbons and P2i plasma polymerisation

treatments are tabulated in Table 8.1 and indicate the obvious presence of surface

fluorine associated with the fluorocarbons. Examination of the C (1s) spectra of the

F-01 and F6 fluorocarbon treated cotton fabrics indicated the presence of peak

intensity at 291.1eV and 293.4eV which can be assigned to CF2 and CF3 species.

With both fluorocarbons the CF2 component is largest component reflecting their

greater contribution to the C6 and C8 perfluoro chains. The F-01 and F6

fluorocarbons are based on F8 and F6 perfluoro chains but the observed XPS

fluorine % atomic compositions are surprisingly similar and probably explains why

the water and oil repellency of the F-01 and FRN6 treated fabrics are similar, as

stated in Chapter 6.

The effect of ISO CO6 washing the fluorocarbon treated 150g/L pigment dyed fabric

was to reduce the intensity of F (1s) photoelectron emission due to polymer

re-orientation and the perfluoro chains being “buried” in the sub-surface, Table 8.1,

Figures 8.11 and 8.19. However the subsequent heat pressing re-orientated the

fluorocarbon surface polymer almost back to its original spectral intensity and


199

regenerated the liquid repellency, Table 8.1, Figures 8.12 and 8.20.

Table 8.1 XPS surface elemental composition of blue pigment dyed cotton fabric

treated with fluorocarbons

Pigment

Formulation

Conc. g/L

Fluorocarbon

Type

Fluorocarbon

Conc. g/L

Atomic Composition %

C1s O1s F1s N1s

Untreated

Cotton Control 1 0 78.8 20.9 ND 0.3

Blue 10

Control 0 69.6 28.8 ND 1.3

F-01 40 49.8 9.1 40.9 0.2

60 49.6 7.5 42.7 0.2

FRN6 45 50.9 8.8 40.2 0.1

60 49.8 8.5 41.6 0.1

P2i

Process1 46.9 7.4 45.6 0.2

Process2 45.4 6.1 48.4 0.05

Process3 44.5 6.1 49.4 0.04

Blue 100

Control 2 0 78.8 19.5 ND 1.8

F-01 40 50.4 7.1 42.4 0.1

60 49.9 7.1 42.9 0.2

FRN6 45 51.4 9.2 39.3 0.1

60 49.4 7.7 42.8 0.01

P2i

Process1 47.4 7.6 44.9 0.2

Process2 44.6 5.9 49.4 0.1

Process3 44.2 6.1 49.7 0.0

Blue 150

Control 3 0 78.9 19.1 ND 2.0

F-01

40 49.2 7.7 42.7 0.4

60 51.6 6.9 41.3 0.2

601 59.1 9.9 30.5 0.5

602 47.7 6.8 45.3 0.2

FRN6

45 49.7 8.6 41.5 0.2

60 49.9 8.2 41.7 0.2

601 55.5 10.1 34.1 0.3

602 50.3 8.0 41.5 0.2

P2i

Process1 48.0 8.2 43.5 0.3

Process2 45.2 6.1 48.7 0.01

Process3 45.2 6.2 48.6 0.1

Process31 53.2 14.8 31.7 0.3

Process32 49.4 11.9 38.4 0.3

1- Washed

2- Washed and heat pressed

ND- Not detected


200

Figure 8.1 C (1s) XP spectrum of untreated cotton fabric

Figure 8.2 C (1s) XP spectrum of 10g/L blue dyed cotton fabric


C 1s/6

C 1

s

x 102

10

20

30

40

50In

tensi

ty

300 296 292 288 284 280 276

Bi ndi ng E nergy (eV)

C 1s/14

C 1

s

x 102

5

10

15

20

25

30

35

40

45

Inte

nsi

ty

300 296 292 288 284 280 276


C 1s/22

C 1

s

x 102

10

20

30

40

50

60

Inte

nsi

ty

296 292 288 284 280 276



201



F-01


F-01

C 1s/30

C 1

s

x 102

10

20

30

40

50

60In

tensi

ty

300 296 292 288 284 280 276


C 1s/6

C 1s

C 1

s

x 102

2

4

6

8

10

12

14

16

18

20

22

Inte

nsi

ty

300 295 290 285 280 275 270


C 1s/14

C 1s

C 1s

C 1s

C 1s

C 1s

C 1

s

x 102

5

10

15

20

25

Inte

nsi

ty

300 295 290 285 280 275 270



202


F-01


F-01


F-01

C 1s/22

C 1s

C 1s

C 1

s

x 102

5

10

15

20

25

30

Inte

nsi

ty

300 295 290 285 280 275 270


C 1s/30

C 1sC 1s

C 1

s

x 102

5

10

15

20

25

Inte

nsi

ty

300 295 290 285 280 275 270


C 1s/38

C 1s

C 1s

C 1

s

x 102

5

10

15

20

25

30

Inte

nsi

ty

300 295 290 285 280 275 270



203


F-01


60g/L F-01


fabric treated with 60g/L F-01

C 1s/46

C 1sC 1s

C 1

s

x 102

5

10

15

20

25

30

Inte

nsi

ty

300 295 290 285 280 275 270


C 1s/38

C 1

s

x 102

5

10

15

20

25

30

35

40

45

Inte

nsi

ty

296 292 288 284 280 276


C 1s/46

C 1

s

x 102

5

10

15

20

25

30

Inte

nsi

ty

296 292 288 284 280 276



204


FRN6


FRN6


FRN6

C 1s/54

C 1s

C 1s

C 1

s

x 102

2

4

6

8

10

12

14

16

18

20

22

Inte

nsi

ty

300 295 290 285 280 275 270


C 1s/62

C 1s

C 1s

C 1

s

x 102

5

10

15

20

25

30

Inte

nsi

ty

300 295 290 285 280 275 270


C 1s/70

C 1s C 1s

C 1s

C 1

s

x 102

5

10

15

20

25

30

Inte

nsi

ty

300 295 290 285 280 275 270



205


FRN6


FRN6


FRN6

C 1s/78

C 1sC 1s

C 1

s

x 102

5

10

15

20

25

Inte

nsi

ty

300 295 290 285 280 275 270


C 1s/86

C 1s

C 1s

C 1

s

x 102

5

10

15

20

25

Inte

nsi

ty

300 295 290 285 280 275 270


C 1s/94

C 1s

C 1s

C 1

s

x 102

5

10

15

20

25

Inte

nsi

ty

300 295 290 285 280 275 270



206


60g/L FRN6


fabric treated with 60g/L FRN6

The high-resolution scans of the C (1s) region for fabrics treated in the P2i plasma

polymerisation chamber are presented in Figures 8.21-8.31. The CF3 fluorocarbon

species are present in higher concentration than the aqueous fluorocarbon polymer

chains and the P2i surface fluorine concentration was higher than the aqueous

fluorocarbon treatments. This spectral feature was more obvious with the fabrics

treated by the P2i Processes 2 and 3.

Similar to the F-01 and FRN6 surface treatments the effect of washing the P2i

treated fabrics was to reduce the surface fluorine which was only partially recovered

after heat pressing. This partial recovery was a reflection of the nature of the

C 1s/54

C 1s

C 1

s

x 102

5

10

15

20

25

30

35

40

Inte

nsi

ty

296 292 288 284 280 276


C 1s/62

C 1s

C 1

s

x 102

5

10

15

20

25

30

Inte

nsi

ty

296 292 288 284 280 276



207

fluoropolymer and the absence of a hydrophilic copolymer component. As identified

in Chapter 6, the water and oil repellency of fabrics treated with the P2i system was

higher than those of fabrics treated with the F-01 and FRN6 fluorocarbons and

maintained a good repellency levels even after washing, especially for Process 2 and

3 treatments. However subsequent hot pressing did not recover the original water

repellency performance but heat pressing did return the original oil repellency levels.

The nature of this difference in behaviour is unclear at present.



C 1s/102

C 1s

C 1s

C 1

s

x 102

5

10

15

20

Inte

nsi

ty

300 295 290 285 280 275 270


C 1s/110

C 1s

C 1s

C 1s

C 1s C 1s

C 1s

C 1

s

x 102

5

10

15

20

25

Inte

nsi

ty

300 295 290 285 280 275 270



208




C 1s/118

C 1s

C 1s

C 1s

C 1s

C 1

s

x 102

5

10

15

20

25In

tensi

ty

300 295 290 285 280 275 270


C 1s/126

C 1

s

x 102

5

10

15

20

25

Inte

nsi

ty

300 295 290 285 280 275 270


C 1s/134

C 1s

C 1s

C 1s

C 1sC 1s

C 1s

C 1

s

x 102

5

10

15

20

25

30

Inte

nsi

ty

300 295 290 285 280 275 270



209




C 1s/142

C 1s

C 1sC 1s C 1s

C 1s

C 1

s

x 102

5

10

15

20

25

30

Inte

nsi

ty

300 295 290 285 280 275 270


C 1s/150

C 1s

C 1s

C 1s

C 1s

C 1

s

x 102

5

10

15

20

Inte

nsi

ty

300 295 290 285 280 275 270


C 1s/158

C 1

s

x 102

5

10

15

20

25

30

Inte

nsi

ty

300 295 290 285 280 275 270



210


Figure 8.30 C (1s) XP spectrum of washed 150g/L blue dyed cotton treated with P2i

Process 3


treated with P2i Process 3

C 1s/166

C 1s

C 1s

C 1sC 1s

C 1s

C 1

s

x 102

5

10

15

20

25

30In

tensi

ty

300 295 290 285 280 275 270


C 1s/70

C 1s

C 1

s

x 102

5

10

15

20

25

30

Inte

nsi

ty

296 292 288 284 280 276


C 1s/78

C 1s

C 1

s

x 102

5

10

15

20

25

30

Inte

nsi

ty

296 292 288 284 280 276



211

8.2 ToF-SIMS Analysis of Blue Pigment-dyed Cotton

Treated with Fluorocarbon Finishes

Whilst the XPS technique can provide information about the fibre surface elemental

composition, oxidation state and chemical environment, the complementary

ToF-SIMS analysis is beneficial in that the molecular nature of the surface species

can also be characterised [1]. An important component of the study was the effect of

laundering with standard ECE detergent and the surfactant adsorption on the Matrix

OSD and fluorocarbon treated Matrix OSD fabrics. Therefore the ECE detergent

was first characterised in order to assign subsequent binding of surfactant

constituents.

8.2.1 ECE Detergent with Phosphates

The positive ion spectra show the presence of non-ionic surfactants which are a

mixture of C12-C18 fatty alcohol ethoxymers, Table 8.2 and Figures 8.33-8.34, but in

general the C16 and C18 components were the dominant species. Examination of the

relative peak intensities in the positive ion spectra indicated that the sociated C18EO7

and C18EO8 species were present in the highest concentration in the powder

formulation.

The negative ion spectra showed that the C11 alkyl benzene sulphonate was present

in the greatest concentration, Figure 8.34(c). The typical composition of the linear

alkyl benzene sulphonates (LAS) in the washing formulation is as Figure 8.32 [2]:

m/z = 297-, (conc. <1%)

m/z = 311

-, (conc. ~38%)

m/z = 325-, (conc. ~32%) m/z = 339

-, (conc. ~ 18%)

Figure 8.32 Typical composition of the linear alkyl benzene sulphonates (LAS)


212

Examination of the ToF-SIMS negative ion spectra indicates the C11 component was

present in the highest concentration. Other obvious negative ion species evident are

SO3 ,̄ HSO4 ̄and NaSO4 ̄at m/z = 80-, 96

- and 119

-, respectively. Weak signals due

to the C18, 20 and 22 sodium soaps at m/z = 283-, 327

- and 371

-, respectively, were

also observed.

Table 8.2 ToF-SIMS Fatty alcohol ethoxylates ion assignments

C12H25-[CH2CH2O]n-OH/Na+

N 1 2 3 4 5 6 7 8 9 10 11

mass/z 253 297 341 385 429 473 517 561 605 649 693


N 1 2 3 4 5 6 7 8 9 10 11

mass/z 267 311 355 399 443 487 531 575 619 663 707


N 1 2 3 4 5 6 7 8 9 10 11

mass/z 281 325 369 413 457 501 545 589 633 677 721


N 1 2 3 4 5 6 7 8 9 10 11

mass/z 295 339 383 427 471 515 559 603 647 691 735

N 12 13 14 15 16 17

mass/z 779 823 867 911 955 999


N 1 2 3 4 5 6 7 8 9 10 11

mass/z 309 353 397 441 485 529 573 617 661 705 749

N 12 13 14 15 16

mass/z 793 837 881 925 969


N 1 2 3 4 5 6 7 8 9 10 11

mass/z 323 367 411 455 499 543 587 631 675 719 763

N 12 13 14 15 16

mass/z 807 851 895 939 983


N 1 2 3 4 5 6 7 8 9 10 11

mass/z 337 381 425 469 513 557 601 645 689 733 777

N 12 13 14 15 16

mass/z 821 865 909 953 997


213

(a)

(b)

(c)

(d)

Figure 8.33 (a)-(d) ToF-SIMS positive ion spectra of ECE detergent powder


214

(a)

(b)

(c)

Figure 8.34 (a)-(c) ToF-SIMS negative ion spectra of ECE detergent powder

8.2.2 Matrix OSD Binder Applied to Cotton Fabric

The ToF-SIMS spectra of untreated cotton are shown in Figure 8.36, which indicate

the presence of a complex mixture of chemical species at the cotton fibre surface. The

cellulosic signals can be observed, for example the cellulose-specific m/z 71-, 87

-,

113- and 221

-, Figure 8.36(c)-(d).

CH2=CHCOO-

HOCH=CHCOO-

m/z = 71- m/z=87

-

m/z = 113- m/z = 221

-

Figure 8.35 Cellulose-specific


215

(a) positive ion mode

(b) positive ion mode

(c) negative ion mode

(d) negative ion mode

(e) negative ion mode

Figure 8.36 ToF-SIMS spectra of untreated cotton fabric


216

The “clean” cotton fabric also has residues from the scouring detergent where alkyl

benzene sulphonates were present in the negative ion spectrum at m/z = 311-, 325

-

and 339- and alkyl sulphates (C12H25OSO3

-, C14H29OSO3

-, C16H33OSO3

- and

C18H37OSO3-) present at m/z = 265, 309, 353 and 397

-.

The ToF-SIMS spectra of the cotton fabric treated with 135g/L of Matrix OSD

binder and the related washed binder treated cotton fabric are presented in Figures

8.37-8.40. The binder is reported to be a polyacrylate derivative with a siloxane

softener incorporated therefore the typical polyacrylate signals and PDMS

(polydimethylsiloxane) signals are presented in Tables 8.3-8.5. It is evident from the

spectra that the silicone is clearly present at the binder surface and to some extent

complicates the assignment of the binder species, nevertheless typical ethyl acrylate

species can be observed in both the positive and negative ion spectra, Figure 8.37

and 8.38.

Table 8.3 Polyacrylate positive ion assignments

m/z

CH3

+ 15

+

C2H5

+ 29

+

C3H5

+ 41

+

CH2=CH-C≡O+ 55

+

C4H9

+ 57

+

+O≡C-O-CH3 59

+

+O≡C-O-C2H5 73

+

+O≡C-O-C4H9 101

+

+CH2–CH2-COO-C2H5 101

+

+CH2–CH2-CH2-COO-CH3 101

+

+CH2–CH2-CH2-COO-C2H5 115

+


217

Table 8.4 Poly(acrylate) negative ion assignments

m/z

-CH2–COO-CH3 73-

-CH2–COO-C4H9 101-

-CH2–CH2-COO-C2H5 101-

-CH2–CH2-COO-C4H9 115-

Table 8.5 PDMS (-[(CH3)2SiO]n-) ion assignments

m/z

Si+ 28

+

SiH+ 29

+

CH3Si+ 43

+

(CH3)2SiH+ 59

+

(CH3)3Si+ 73

+

[(CH3)3Si2O2]+ 133

+

(CH3)3SiOSi(CH3)2

+ 147

+

[(CH3)5Si3O3]+ 207

+

(CH3)3SiOSi(CH3)2OSi(CH3)2

+ 221

+

(CH3)3Si[OSi(CH3)2]2OSiO+ 281

+

Si- 28

-

SiH- 29

-

CH3SiO- 59

-

OSiO- 60

-

OSi(CH3)O- 75

-

[(CH3)Si2O3]- 119

-

OSi(CH3)2OSi(CH3)O- 149

-

OSi(CH3)2OSi(CH3)2OSi(CH3)O- 223

-


218

(a)

(b)

(c)

(d)

(e)

Figure 8.37 (a)-(e) ToF-SIMS positive ion spectra of Matrix OSD binder applied to

cotton fabric


219

(a)

(b)

(c)

Figure 8.38 (a)-(c) ToF-SIMS negative ion spectra of Matrix OSD binder applied to

cotton fabric

After washing, there are significant changes in the ToF-SIMS spectral intensity;

particularly with the signal at 23+ associated with Na

+ dominating the positive ion

spectrum, Figure 8.37(a). In semi-quantifying the surface sodium level, an internal

standard peak, 41+ (C3H5

+) can be used as the indicator. The ratio of sodium is

calculated: 23+/41

+ ratio of unwashed samples is 0.63, while the ratio of washed

samples is 2.1. The polyacrylate and PDMS signals are all relatively reduced by

washing as well.

In Section 8.2.1, the ECE detergent power was analysed by ToF-SIMS and found to


220

contain a mixture of C12-C18 fatty alcohol ethoxylates with the C18EO7/8 fatty

alcohol ethoxylates predominating. Examination of the positive ion spectrum of

unwashed samples at higher masses also showed the presence of fatty alcohol

ethoxylates, Figure 8.37(d)-(e). That is probably due to their presence in the binder

system. After washing, the intensity of fatty alcohol ethoxylates was lowered with

the main peak intensity arising due to the C18EO3-7, Figure 8.40 (c)-(d), due to their

lower water solubility and greater affinity for the binder.

The ToF-SIMS negative ion spectrum of washed Matrix OSD binder treated fabrics

indicate the presence of alkyl benzene sulphonates adsorbed onto the fibre surface,

Figures 8.41(a), with the intensity of the more hydrophobic LAS “sticking” more

than the shorter chain more water soluble derivatives:

>

>

Figure 8.39 The intensity of the more hydrophobic LAS


221

(a)

(b)

(c)

(d)

(e)

Figure 8.40 (a)-(e) ToF-SIMS positive ion spectra of ISO CO6 washed cotton fabric

with applied Matrix OSD Binder


222

(a)

(b)

(c)

Figure 8.41 (a)-(c) ToF-SIMS negative ion spectra of ISO CO6 washed cotton fabric

with applied Matrix OSD Binder

8.2.3 P2i Process 3 Treatment

The Matrix OSD fabric was treated under the P2i Process 3 conditions and was

studied unwashed, washed and washed and heat pressed.

The positive ion ToF-SIMS spectra of unwashed fabric showed the presence of a

series of positive ion fluorocarbon species. As can be seen in Figure 8.42(a)-(c), the

corresponding species detected at the fibre surface are identified and tabulated in

Table 8.6. In the negative ion mode, a strong signal of F- ion is shown at 19

-, Figure

8.43(a), together with a series of negative ion fluorocarbon species assigned in Table


223

8.7. The predominant longest perfluoro chain species formed during the P2i process

appears to be the C9F15- at m/z=393

-.

After washing, the fabrics have experienced a noticeable loss of oil repellency and

water repellency, as indicated in Chapter 6. While some evidence for surfactant

build-up from the detergents was evident through the LAS species on the textile

surface the loss of repellency maybe related to loss of fluorine from the surface or

molecular re-orientation and a reduction in surface fluorine species concentration,

Figures 8.44-8.45. The surface compositional changes associated with the F- species

at m/z = 19- have been calculated by referencing to the internal standard peak at m/z

= 25- (C2H

-). The 19

-/25

- ratio is 16.3 before washing while it is 5.5 after washing.

The effect of laundering was to deposit alkyl benzene sulphonates on the fibre

surface with the longer chain C13 species predominating due to its lower solubility

and higher affinity for the fibre rather than the higher concentration C11 and C12

derivatives in the original powder. C13 derivative is the most hydrophobic one of the

major components and therefore it has a stronger substantivity for the fabric surface.

Heat pressing causes the perfluoro-chains to orientate from the “sub-surface”

aqueous environment to the “exposed” repellent air condition. The intensities of

fluorocarbon species are higher than the washed ones, Figures 8.46-8.47, but the

ratio of F-/C2H

- is 15 which is almost the same as the unwashed samples. This is

reflected in the recovered oil/water repellency. There are still LAS on the surface of

heat pressed samples, although the intensities are much lower than with the washed

samples. Still, the longer chain C13 species predominates due to its lower solubility

and higher affinity for the fibre rather than the higher concentration C11 and C12

derivatives in the original powder.


224

Table 8.6 Positive fluorocarbon species

Fluorocarbon species Atomic mass units

CF+ 31

+

CF2+ 50

+

CF3+ 69

+

C3F3+ 93

+

C2F4+ 100

+

C2F5+ 119

+

C3F5+ 131

+

C3F7+ 169

+

C4F7+ 181

+

C4F9+ 219

+

C5F9+ 231

+

C6F11+ 281

+

C7F13+ 331

+

C8F15+ 381

+

Table 8.7 Negative fluorocarbon species

Fluorocarbon species Atomic mass units

F- 19

-

F2- 38

-

CF3- 69

-

C2F5- 119

-

C3F5- 131

-

C3F7- 169

-

C5F7- 193

-

C6F9- 243

-

C7F9- 255

-

C7F11- 293

-

C9F13- 355

-

C9F15- 393

-


225

(a)

(b)

(c)

Figure 8.42 (a)-(c) ToF-SIMS positive ion spectra of P2i Process 3 treated cotton

fabric with applied Matrix OSD


226

(a)

(b)

(c)

Figure 8.43 (a)-(c) ToF-SIMS negative ion spectra of P2i Process 3 treated cotton

fabric with applied Matrix OSD


227

(a)

(b)

(c)

(d)

(e)

Figure 8.44 (a)-(e) ToF-SIMS positive ion spectra of ISO CO6 washed P2i Process 3

treated cotton fabric with applied Matrix OSD


228

(a)

(b)

(c)

Figure 8.45 (a)-(c) ToF-SIMS negative ion spectra of ISO CO6 washed P2i Process 3



229

(a)

(b)

(c)

Figure 8.46 (a)-(c) ToF-SIMS positive ion spectra of washed and heat pressed P2i

Process 3 treated cotton fabric with applied Matrix OSD


230

(a)

(b)

(c)

Figure 8.47 (a)-(c) ToF-SIMS negative ion spectra of washed and heat pressed P2i

Process 3 treated cotton fabric with applied Matrix OSD

8.2.4 FRN6 Treatment

The 135g/L Matrix OSD binder treated fabric was further treated with 60g/L FRN6

and subsequently washed and washed & heat pressed.

In general, the ToF-SIMS fluorocarbon ions observed in the FRN6 treated samples,

Figures 8.48-8.49, are similar to those observed in the P2i treated fabric ToF-SIMS

spectra, Tables 8.3 and 8.4. However, comparison with the ToF-SIMS spectra of the

P2i treated fabrics indicates the intensity of each fluorocarbon species in the FRN6


231

fabric ToF-SIMS spectra are relatively lower. The 19-/25

- ratio is 11.2, while it is

16.3 for the P2i treated fabrics. The ToF-SIMS peak intensities at m/z = 281+ can be

assigned to C6F11+ suggesting that the perfluoro chains in the FRN6 finish are indeed

C6-based fluorocarbons. However examination of the negative ion spectrum

surprisingly shows a strong peak at m/z=293- which can be assigned to C7H11

-. The

nature of this anomaly is uncertain at present.

After washing, unlike the comparable P2i treated samples, there is little decrease in

the fluorocarbon related ion peak intensities, Figure 8.50-8.51. The 19-/25

- ratio is

11.6, which is almost the same as the unwashed samples. Further the water

repellency remains at the same level while the oil repellency fails, mentioned in

Chapter 6. The effect of laundering was to deposit alkyl benzene sulphonates on the

fibre surface as shown in the previous section, Figure 8.51(c). Like the washed

binder treated samples, the longer chain C13 species predominates due to its lower

solubility and higher affinity for the fibre rather than the higher concentration C11

and C12 derivatives in the original powder. C13 derivative is the most hydrophobic

surfactant of the major components and therefore it has a stronger substantivity for

the fabric surface. Interestingly, the intensity of LAS for those samples are treated

by P2i is higher than those treated by FRN6

Heat pressing of the washed fabrics caused a small decrease in ion intensities and

associated variable repellency performance, Figure 8.52-8.53. The ratio of F-/C2H

- is

10.5 which is almost the same as the unwashed and washed samples and is evidence

of the recovered oil repellency. There is still LAS on the surface of heat pressed

samples, although the intensities are slightly higher than washed samples.


232

(a)

(b)

(c)

(d)

Figure 8.48 (a)-(d) ToF-SIMS positive spectra of 60g/L FRN6 treated cotton fabric

with applied Matrix OSD


233

(a)

(b)

(c)

Figure 8.49 (a)-(c) ToF-SIMS negative spectra of 60g/L FRN6 treated cotton fabric



234

(a)

(b)

(c)

Figure 8.50 (a)-(c) ToF-SIMS positive ion spectra of ISO CO6 washed 60g/L FRN6



235

(a)

(b)

(c)

Figure 8.51 (a)-(c) ToF-SIMS negative ion spectra of ISO CO6 washed 60g/L FRN6



236

(a)

(b)

(c)


FRN6 treated cotton fabric with applied Matrix OSD


237

(a)

(b)

(c)


FRN6 treated cotton fabric with applied Matrix OSD

8.2.5 F-01 Treatment

The fabrics treated by 135g/L binder and 60g/L F-01 were tested at three different

conditions: unwashed, washed and washed & heat pressed.

The ToF-SIMS peak intensities at m/z = 231+, 281

+, 331

+, 381

+ can be assigned to

C5F9+, C6F11

+, C7F13

+ and C8F15

+ suggesting that the perfluoro chains are C5-, C6-,

C7- and C8-based fluorocarbons or the lower perfluoro analogues are ion fragments

generated by the analysis. In contrast the negative ion spectrum shows evidence of


238

the C9F13- and C9F15

- species at m/z = 355

- and 393

-, respectively. The nature of this

anomaly is uncertain at present.

In general, the fluorocarbon species in the ToF-SIMS spectra of F-01 treated

samples, Figure 8.54-8.55, are similar to the P2i treated and FRN6 treated samples

which are shown in Tables 8.3 and 8.4. However, comparison of P2i treated and

FRN6 treated samples indicates that the intensity of each fluorocarbon species in

ToF-SIMS spectra of F-01 treated samples is relatively lower than P2i treated

samples and slightly higher than the FRN6 treated samples. However it is clearly

apparent that the F- in the negative ToF-SIMS spectra, Figure 8.55, dominates the

spectrum and the organic ions are less obvious.

After washing, there is some decrease of the perfluoro ion species, Figure 8.56-8.57,

and is the primary reason for the reduction in the observed water and oil repellency.

The effect of laundering was also to deposit alkyl benzene sulphonates on the fibre

surface as shown in previous section, Figure 8.57(c), and again the deposition and

relative substantivity is similar to the previous experiments: C13>C12>C11.

Interestingly, the intensity of LAS deposition is marginally greater in FRN6 treated

fabrics and maybe related to the lower repellency performance.

Again subsequent heat pressing increases the relative intensities of the perfluoro ion

species, but still lower than the unwashed samples, Figure 8.58-8.59. However it

again explains the observed recovery in oil repellency. The intensities of LAS left on

the fabric surface are slightly higher than the washed samples, which is the same as

the FRN6 treatment but opposite to the P2i treated fabrics.


239

(a)

(b)

(c)

Figure 8.54 (a)-(c) ToF-SIMS positive spectra of 60g/L F-01 treated cotton fabric



240

(a)

(b)

(c)

Figure 8.55 (a)-(c) ToF-SIMS spectra of 60g/L F-01 treated cotton fabric with applied

Matrix OSD


241

(a)

(b)

(c)

Figure 8.56 (a)-(c) ToF-SIMS positive ion spectra of ISO CO6 washed 60g/L F-01



242

(a)

(b)

(c)

Figure 8.57 (a)-(c) ToF-SIMS negative ion spectra of ISO CO6 washed 60g/L F-01



243

(a)

(b)

(c)


F-01 treated cotton fabric with applied Matrix OSD


244

(a)

(b)

(c)


F-01 treated cotton fabric with applied Matrix OSD

8.3 Conclusions

XPS and ToF-SIMS have been used to successfully probe the outer surface of the

pigment dyed textile fabric treated with a range of wet and dry fluorocarbon finishes.

The fluorocarbon finishes have been characterised and their surface composition

related to the observed repellency and deposit surfactants on the fibre surface.

The XPS technique has provided an insight into the relative proportion of CF3 and

CF2 contribution to the surface fluoropolymers and the ToF-SIMS technique has


245

provided information about the molecular structure of the finishes. In particular the

FRN6 finish appears to be “built” from C6 chain chemistry.

Some strong polyacrylate and PDMS signals were observed in the ToF-SIMS figures.

Therefore, the binder composition appears to be confirmed as an ethyl polyacrylate

and silicone softener.

8.4 References

1. Mitchell, R., Carr, C. M., Parfitt, M., Vickerman, J. C. and Jones, C., Surface

Chemical Analysis of Raw Cotton Fibres and Associated Materials, Cellulose,

2005, 12(6): p.629-639.


Improve Crease Resist and Repellancy Properties, UMIST PhD Thesis,

1999.

Chapter 9 Conclusions and Future Work

246


9.1 Summary and Conclusions

The Matrix OSD pigment dyeing system has been reported to offer benefits in terms

of processing cost and environmental impact. From the initial studies it was apparent

that while dry rub fastness, mechanical rigidity and washing performance were

generally acceptable the wet rub fastness of the printed fabrics presented a technical

challenge. On increasing the pigment incorporated into the surface binder film while

the colour strength increased the fastness properties decreased reflecting the

integrity of the film being compromised by the higher pigment concentrations. The

presence of silicone softener in the binder formulation offered some benefits in

terms of colour strength, handle and fastness but these effects are most likely due to

the surface film increasing specular reflectance and lubrication at the materials

interface.

SEM analyses of the pigment dyed fabrics offered further insight as to the colour

loss after rubbing with the Martindale Flat Abrasion tester. With the increase of

formulation concentration, more pigment was present on the fabric surface and

accordingly caused that more colour and associated polymer binder were lost during

rubbing. However the loss of the colourant did not affect the overall fabric

integrity/strength but rather were a visual effect.

Pigment dyeing offers the potential for colouration of any substrate however with

the Matrix OSD system it is apparent that comparison between 100% polyester

synthetic fabric and a polyester/cotton blend (55:45), the colour yield and durability

on the cellulosic fabrics was better. Therefore in the development of the project

cotton was the main focus as the main experimental substrate and improving the


247

fastness performance.

The studies aimed at modifying the pigment dyeing system with a view to

improving fastness, in particular improving the wet rub fastness, involved four

different approaches based on pre-cationization of the fabric (Chapter 5),

incorporation of crosslinkers into the binder formulation (Chapter 5), UVO pre-

treatment of the fabric (Chapter 5), and wet fluorocarbon treatment (Chapter 6) and

dry plasma polymerisation treatment (Chapter 7).

Cationizing the cotton fabrics prior to pigment dyeing improved the wet rub fastness

performance of the Matrix OSD dyeing system, but the other fastness properties

were in general unchanged. The cationization is most likely changing the surface

interface chemistry and improving adhesion and covalent bonding to the fibre

surface

Similarly crosslinking treatments enhanced the colour fastness performance, due to

the improvement of the bonding between the binder and fabrics. The crosslinking

pre-treatment offers better performance than the combined application method in

terms of improving the wet rub fastness. Moreover, the crosslinker has almost no

effect on wash fastness which always remains at an acceptable performance level

with most crosslinkers. Of the system assessed the Knittex MLF New pre-treatment

offers the best option to improve the colour fastness, with the optimum application

level being 40g/L.

Unlike the benefits of UVO pre-treatment previously observed for other long liquor

fabric dyeing studies, in this study it was established that the pigment dyeing

performance was reduced after the sensitised photo-oxidation treatment. The reason

for this decrease in performance is unclear but it is perhaps due to the oxidised fibre

surface interface not providing appropriate reactive functionalities or the mechanical


248

strength of the interface polymer weakening the integrity of the cellulose/pigment

binder layer.

The effect of applying fluorocarbons to the pigment dyed fabrics had a beneficial

effect on wash fastness and wet rub fastness, while dry rub fastness was marginally

reduced at higher fluorocarbon application levels. Comparison of the fastness

performance of the different fluorocarbon treated cotton indicated the best

application condition was found when the dyed samples were aftertreated with

20g/L Shield F-01 with 8g/L Shield extender FCD. At this F-01 concentration, rub

fastness and wash fastness were all at an excellent level, above 4. Similarly with the

polycotton fabric the benefits of the F-01 treatment were apparent, particularly at the

20g/L application level. Although the dry P2i plasma treatment cannot achieve a

similar level of fastness as the aqueous fluorocarbon treatments, it still imparted

improved water/oil repellency and fabric handle.

SEM analysis of the fabrics damage due to the wet and dry rubbing indicates wet

abrasion is more damaging but that there was less damage in the samples treated

with the F-01 fluorocarbon.

The surface sensitive XPS and ToF-SIMS techniques have been used to successfully

probe the outer surface of the pigment dyed textile fabric treated with a range of wet

and dry fluorocarbon finishes. The fluorocarbon finishes have been characterised

and their surface composition related to the observed repellency and deposit

surfactants on the fibre surface. The XPS technique has provided a valuable insight

into the relative proportion of the CF3 and CF2 polymer components in the surface

fluoropolymers and the ToF-SIMS technique has provided information about the

molecular structure of the finishes. In particular the FRN6 finish is clearly identified

as “built” from C6 chain chemistry.


249

When fluorocarbon application treatment was combined with the pigment dyeing

systems, there was a deleterious effect on abrasion resistance and a reduced

performance was observed. However, when the fluorocarbon is directly applied onto

undyed cotton fabrics, the abrasion resistance was improved, the Oleophobol

treatment giving the best result at the concentration of 60g/L. The combination of

the two systems appears to have a deleterious effect and the nature of this

antagonistic interaction is uncertain at present.

Water and oil repellency imparted by the fluorocarbon was the same on uncoloured

cotton as that observed on coloured cotton. There were almost no repellency results

related to softener in binder, except for the exhaustion application method with

7%owf Oleophobol 7713 and 8%owf Rucoguard LAD which the water and oil

repellency results are obviously higher than the padding application method. This is

probably because the longer treating time during the exhaustion application makes

more chemicals staying on the fabric surface.

A range of plasma pre- treatments prior to pigment dyeing were examined but only a

marginal benefit on fastness properties and to some extent slightly decreased dry rub

fastness were observed. However, colour strength was improved under all gas

conditions. Mixed gases treatments (He & O2 and He & N2) were better than the

single gas treatment (He), although again the nature of the specific chemical

modifications is unclear. Plasma aftertreatments, using both Ar and N2 atmospheres,

improved the fastness, particularly wet fastness, when the binder heat curing process

was before plasma treatment probably due to crosslinking the outer polymer surface.

Overall, the treatment which showed the most beneficial improvement in this study

was the 20g/L Shield F-01 after-treatment where all fastness properties are at an

excellent level, above 4. In addition the colour strength was unaffected.


250

9.2 Future Work

- In recognising the benefits of surface fluorocarbon finishes and the influence of the

surface interface on pigment binder fastness performance further studies should

focus on the ToF-SIMS chemical analysis technique in that it provides molecular

and functional group information. This insight may be beneficial in identifying and

engineering better surface adhesion and bonding at the treated cotton surface, hence

leading to better fastness performance.

- The surface interface will also affect the mechanical properties of the treated cotton

fabric, in particular fabric handle. The effect of washing on the handle should be

examined further and therefore the relationship between surface binder and

fluorocarbon composition and the associated handle properties determined.

- The repellency performance after fluorocarbon treatments should be investigated

particularly due to the relatively low repellency results in this study. In the same

time the repellency behaviour on different textile materials, such as wool, polyester

and polyester/cotton should be examined further.

- The optimisation of the pigment dyeing system on other single fibre or blend

fabrics, such as wool, silk, polyester and polyester/cotton should be investigated in

order to broaden the application and commercial scope and improve fastness

performance.

- The beneficial applications in pigment dyeing system should be studied in related

pigment printing system to overcome the fastness and handle problems.

an investigation into the development of environmentally

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