wet processing lecture no.1

8/7/2019 Wet Processing Lecture No.1

http://slidepdf.com/reader/full/wet-processing-lecture-no1 1/19

Introduction to textile engineering

Wet processing



Introduction

Fabrics str aight off the loom or knitting

machines are called GREIGE FABRICS These do not appeal to the consumer for a

number of reasons

Fabrics often look unattr active because of

lack of color



Yarns in greige f abrics may have size

applied for weaving or lubricating oil appliedfor knitting

These additives, if not removed, make the

f abric feel stiff and unpleasant in handle



Fibers and yarns are stretched during yarn

and f abric manuf acturing, and the residualstress in the fiber and yarn will lead to

dimensional stability (e.g. shrinkage)

Any stains and natur al color on the greige

f abric should also be removed before theapplication of color to the f abrics



There are many aesthetic and functional

requirements that greige f abrics have tosatisf y for different end-use applications

Most textile f abrics require pre-treatment

before they can be dyed and finished



After the color application, the f abric is

always distorted and further finishingtreatment is required to rectif y this problem

and to further enhance the functionality of the

f abric



Fabrics made from different fiber types are

often finished differently

FOR THESE RE ASONS, TEXTILES ARE ALMOST ALW AYS DYED AND FINISHED

BEFORE USE



Wet processing can be described as

the treatment of GREIGE CLOTH withdifferent chemicals to prepare it for color

application

Application of color onto the f abric via dyeing

or printing



Application of different types of finish onto

the f abric as required Treating the textile effluent gener ated by the

wet processing



Departments in wet processing

Pre-treatment

Color kitchen Dyeing and printing

Finishing

Testing Labor ator y



Processes involved in wet processing

Pre-treatment

Inspection and marking Shearing

Singeing



Desizing

Mercerizing Bleaching



Color kitchen

Distribution of dyes, pigments and differentchemicals according to their need



Dyeing and printing

Application of color onto the f abric in case of dyeing, either by exhaust method

or continuous method

In case of printing, then by different types of

printing techniques available like screen

printing, discharge printing e.t.c.



Finishing

Application of different types of finishes ontothe f abric according to the customer

requirements

some of the common finishes are increasing

the handle, improve the lusture, iron free

finish, moth repellent e.t.c.



Testing laborator y

Performing lab scale experiments for pre-treatment processes

Dyeing and printing

Finishing



Performing different tests on the f abric, yarn

and fiber to check different dyeing, printingand finishing properties

Perform the color matching tests



Color has been playing a dominant role in

the life of man from a long time Indigo of ancient India has been in use in the

textile industr y for the last sever al thousand

years.



Among the natur ally occurring dyes also

known as natur al mordant dyes, whichproduces bright red shades and was

extr acted from the roots of madder

wet processing lecture no.1

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