en-12004 impac on adhesive formulations.pdf

NEW STANDARDS MAKE GREATER DEMANDSThe impact of the new EN 12004 standard on formulation technology and raw materials for cement-based tile adhesives

D. Zweifel, R. Baumann, U.Tribelhorn

Contents

Background

Euronorm 12004 – A Synopsis

Summarised results

Proceeding Step by Step

Cement

Sand

Cellulose ethers

Alternative thickener systems

Redispersible polymer powders

Concrete slabs and tiles

Formulations for EN 12004

Experimental

Test methods

The impact of the new EN 12004 standard on formulation technologyand raw materials for cement-based tile adhesives


New Standards Make Greater Demands

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The introduction of the new ENstandards for cement-based tileadhesives, a product for which Dowsupplies METHOCEL* celluloseethers and DOW Latex Powders,is making new demands on tileadhesive producers. Standardisationof the norms involves more strin-gent testing, as well as specific classifications for different tile adhesive qualities, which results in a real challenge in meeting the standards.

Included in the EN 12004 standardare two cement-based tile adhesiveclassifications: C1 which outlinesgeneral requirements, and C2 whichdescribes improved or additional characteristics.These set out theminimum requirements for impro-ved adhesion after 28 days at roomtemperature and under heat, waterand freeze/thaw storage conditions.They also stipulate optional require-ments for fast setting, reduced slipand extended open time.

Sand and cement are the main constituents of cement-bonded,thin-bed adhesives and determinethe properties to a large extent.However, no tile adhesive which can be applied by the thin-bed pro-cedure is formulated with sand andcement alone. Numerous additivesenable an endless range of variationsin processing and end properties tosatisfy the wishes of the end user.

The need to be able to com-pare and to classify this enor-mous variety of products hasexisted for a long time.«Flexible adhesive», «standardadhesive» and «fluidized bed

mortar» are all examples ofattempts to categorise theseproducts. However, it has oftenbeen the case that each region,each country or even eachmanufacturer, used differentterminology.After much debate, the initiative for theregulation of adhesive mortarswas finally agreed earlier thisyear, and with EN 12004coming into effect, the qualityrequirements for cement-basedtile adhesives will now be standardised Europe-wide,replacing conflicting nationalstandards.

The tile adhesive formulator is therefore faced with a stiff challenge– that of demonstrating that hisproducts match the new standards in test conditions. In order to support their customers, the DowMETHOCEL and DLP technicalexperts have carried out a study toquantify the influence of the nume-rous variables of tile adhesives.Thisknowledge should aid the formula-tor to develop tile adhesives thatsatisfy the requirements accordingto EN 12004 (C1 and C2).

The impact of the new EN 12004 standard on formulation technologyand raw materials for cement-based tile adhesives


New Standards Make Greater Demands

*Trademark of the Dow Chemical Company

The aim of the study is to provideyou with data and guidelines toassist you when carrying out testson cement-based tile adhesives inrelation to compliance with EN12004.

The following table (Page 2) provi-des an overview of the require-ments per classification of cement-based tile adhesives.The general classifications C1 andC2 can be combined with additionalrequirements (F,T, E).Designations like C1T or C2TE clearly describe the properties ofcement-based tile adhesives. Rapidhardening adhesives (F) were not asubject of this study.The freeze-thawcycle was also omitted, as manuallyexecuted freeze–thaw yields resultswith limited reproducibility.

The results of studies relating to EN 12004 depend not only on theadhesive being tested, but alsostrongly on the type of tiles and concrete slabs used.This fact mustbe taken into consideration withregard to the «absoluteness» of thetest results. Obviously the materialsused for the tests should meet the specifications required by thenorms.

It is relatively simple to formulate anadhesive which meets the C1 requi-rement. It is not a great obstacle toreach the required 0.5 N/mm2, butthe challenge is rather that of kee-ping the cost as low as possible.Aiming to omit the polymer powderfrom the formulation would beattractive from an economical pointof view but would fail, in our

experience, because of insufficientadhesion after heat aging.The quantity of polymer powder can be reduced when cement of higherquality is used (Table 1).

It is far more difficult to formulatetile adhesives meeting the C2 classification. Tensile adhesion requi-rements of >1.0 N/mm2 representquite a challenge. The results of ourstudies allow the following conclu-sions to be drawn:

• The tensile adhesion strength canbe improved by the use of higherquality cements. An important factto be taken into consideration isthat the increase in tensile adhe-sion, after water immersion orafter heat aging, increases dispro-portionately.

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Making Sense of Euronorm EN 12004 – A Synopsis

Test method Test class C1 Test class C2

Normal setting adhesives

Open time EN 1346 ≥ 0.5 N/mm2 after 20 min ≥ 0.5 N/mm2 after 20 min

Tensile adhesion strength EN 1348 ≥ 0.5 N/mm2 ≥ 1.0 N/mm2

Water immersion EN 1348 ≥ 0.5 N/mm2 ≥ 1.0 N/mm2

Heat aging EN 1348 ≥ 0.5 N/mm2 ≥ 1.0 N/mm2

Freeze-thaw cycle EN 1348 ≥ 0.5 N/mm2 ≥ 1.0 N/mm2

Fast setting adhesives

F: Rapid hardening and ≥ 0.5 N/mm2 after 24 hours ≥ 0.5 N/mm2 after 24 hours

Open time (EN 1346) ≥ 0.5 N/mm2 after 10 min ≥ 0.5 N/mm2 after 10 min

Additional requirements

T: Slip ≤ 0.5 mm ≤ 0.5 mm

E: Extended open time ≥ 0.5 N/mm2 after 30 min

Note: Please refer to the original Std. EN 12004 as reference.This is just an interpretation by Dow.

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• Lightly modified cellulose ethershave limited slip resistance and areduced water demand but showtheir advantage in the tensile adhesion after water immersionand heat aging.

• The loss in slip resistance can becompensated by means of sheetsilicates and/or cellulose fibres.The improvement in slip resistanceis often reached without a compromise in tensile adhesionstrength.

• By optimising the cellulose ether itis possible to develop slip resistantadhesives (slip <0.5 mm) whichyield remarkable tensile adhesionstrength with a DLP 2000 additionlevel of only 1% and 3% (see Formulations 40 and 41).

• By selectively adjusting the poly-mer powder addition level it ispossible to develop tile adhesivesmeeting either C1 or C2 classifi-cation.The newly developed polymer powder DLP 2000 willyield extremely high tensile adhesion strength. If the formula-tion is optimised just to meetminimum requirements, then theseproperties can be met with a relatively low addition level of DLP2000. This clearly has a positiveeffect on the costs. A reduction inthe addition level from 4 to 3% or2 to 1% respectively would resultin a reduction in cost of 10% to15% of the total formulation.

Making Sense of Euronorm EN 12004 – A Synopsis

The conclusions of the study are summarised in the above figure.The effect that each of the investigation parameters has on thefinal properties is shown as an arrow pointing in the influencingdirection.

Summary of study results

5

Portland cement is available in manyquality classifications. Depending onthe particle size and the chemicalcomposition of the clinker, concretewith different compressive strengthvalues is obtained. Fine particles will hydrate better, thus yielding higher strength values.This effectcan also be observed in cement-based tile adhesives as the followingtable demonstrates:

Results: The influence of thePortland cement quality on the tensile adhesion results is not soevident in all tests. Changing the

Portland cement quality from CEM I42.5 to CEM I 52.5, the standardtensile adhesion improved onlyslightly, by an average of 0.2 N/mm2.Comparing the tensile adhesionresults in the same set of tests,after 20 minutes and 30 minutesopen time, no difference can be determined.

Results obtained after the waterimmersion test (+0.3 N/mm2) andafter heat aging (+0.5 N/mm2)demonstrate that the use of better quality Portland cement can be advantageous. Practice has

proven that the tensile adhesion,after these two aging procedures,are the most critical properties in order to meet EN 12004 requirements. Surprisingly the nominal improvement of the tensileadhesion is independent of the redispersible polymer powder level,which means that the increase intensile adhesion strength which isinfluenced by the cement quality,is the same for both the formu-lations containing 1% DLP 2000 and3% DLP 2000.

In order to quantify the effect of the individual components of tileadhesives on its processing and end properties, it is appropriate,given the large number of additives, to proceed step by step andingredient by ingredient.

Parts of the work were done utilising computer-aided statistically designedexperiment planning and evaluation.

Proceeding step by stepCement

Components Formulation 1 Formulation 2 Formulation 3 Formulation 4

Steidle sand Wt.-% 60 60 60 60

CEM I 42.5 Wt.-% 40 40

CEM I 52.5 Wt.-% 40 40

XCS 41120.00 Wt.-% 0.4 0.4 0.4 0.4

DLP 2000 Wt.-% 1.0 1.0 3.0 3.0

Bentone GS 1) Wt.-% 1.0 1.0 1.0 1.0

Arbocell BWW40 2) Wt.-% 0.5 0.5 0.5 0.5

Water Wt.-% 32 31 31 30

Properties

Slip mm 2.0 2.0 4.0 3.0

Tensile adhesion strength

Standard N/mm2 0.88 1.05 1.39 1.56

20 min open time N/mm2 0.86 1.02 1.39 1.34

Water immersion N/mm2 0.70 1.02 0.69 1.01

Heat aging N/mm2 0.15 0.65 1.00 1.50

Table 1: Comparison of two different cement qualities with two different DLP 2000 levels

1) Trademark of Rheox Europe S.A. Bruxelles2) Trademark of Rettenmaier & Söhne, Ellwangen

Because of the relatively high transport costs, the choice of sandremains limited to local sand supplies. Nevertheless, it makessense to investigate the influence ofthe sand quality on the applicationand final properties of tile adhesives.In our studies we limited the number of sands to two very different types. Zimmerli sand is ahighly refined quality with a rathernarrow particle size distribution (0.1 – 0.3 mm) and a very low specific surface (< 0.1 m2/g ). In contrast, Steidle sand has a broader particle size distribution (0 – 0.45

mm) and a substantially higher specific surface (~ 2.9 m2/g).

Results: Comparing the two formulations, where only the sand quality was altered, shows that theproperties obtained are almost identical. Sand has the function of afiller in a tile adhesive formulation.It is therefore to be expected that the influence on the tensileadhesion strength remains low.The sand with the higher specificsurface required two parts morewater in order to maintain the same slip and consistency.

Ground limestone (~60 µm) is oftenadded to the formulation as a finefiller to improve the application properties and a better opticalappearance of the liquid mortar.Formulation 7 (table 2) proves thatthe use of ground limestone inmoderate amounts does not harmthe end properties of a tile adhesive. Excessive amounts ofground limestone, however, have adetrimental effect on open time.

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Proceeding step by stepSand

Components Formulation 5 Formulation 6 Formulation 7

Steidle sand Wt.-% 60 55

Zimmerli sand Wt.-% 60

Limestone 60 µm Wt.-% 5

CEM I 52.5 Wt.-% 40 40 40

METHOCEL 10-0350 Wt.-% 0.5 0.5 0.5

DLP 2000 Wt.-% 2.0 2.0 2.0

Water Wt.-% 28 26 28

Properties

Rheology

BF 0.5 rpm mPa·s 3,971,000 3,793,000 4,298,000

BF 5.0 rpm mPa·s 557,000 528,000 570,000

BF 50 rpm mPa·s 91,000 84,000 94,000

Slip mm 0.5 0.5 0.5


Standard N/mm2 1.16 1.19 1.08

20 min open time N/mm2 1.56 1.59 1.59

30 min open time N/mm2 1.03 1.27 1.02

Water immersion N/mm2 0.43 0.61 0.54

Heat aging N/mm2 0.94 1.00 0.87

Table 2: Different sand qualities in tile adhesive formulations

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Cellulose ethers are among themost important additives in a tileadhesive formulation.These additivessubstantially affect application andend properties. Cellulose ethers arenot only thickeners, controllingwater demand and water retention,but also through the degree ofmodification and their rheologicaleffect, they determine the tensileadhesion strength, slip resistance,open time and application proper-ties.

The following table demonstratesthe influence of different celluloseether types on the properties of a tile adhesive.

Results: METHOCEL 10-0356 is amodified cellullose ether with a

pronounced thickening effect.METHOCEL 10-0350 has a compa-rable viscosity (~10 000 mPa·s)mode-rately modified, and experi-mental celluose ether XCS41120.00 is even less modified. Inthe test series (Table 3) the waterlevel was adjusted in order to obtainapprox. 400 000 mPa·s (5.0 rpm).Depending on the degree of modification the water demandchanged accordingly.The slip resistance decreases with waterdemand, which can be explained bythe lower structural viscosity of theliquid mortar. The structural visco-sity is a measure of how much theviscosity decreases with increasingshear rate. As a measure of thestructural viscosity, the difference ofthe logarithm of the viscosity

determined at 0.5rpm and 50rpm,is used.With the exception of theresults after hot aging, the tensileadhesion results are comparable.Reducing the degree of modificationappears to have a positive effect onthe tensile adhesion after heat aging.The tensile adhesion after heat aging represents in many cases themost critical obstacle to fulfilling EN 12004.The slip resistance andthe water demand are negativelyinfluenced by a lower degree ofmodification. One way out of thisdilemma would be an additive thatincreases the water demand and slip resistance, without having anegative impact on tensile adhesion,especially after hot aging.

Proceeding step by stepCellulose ethers


Zimmerli sand Wt.-% 60 60 60

CEM I 42.5 Wt.-% 40 40 40

METHOCEL 10-0356 Wt.-% 0.4

METHOCEL 10-0350 Wt.-% 0.4

XCS 41120.00 Wt.-% 0.4

DLP 210 Wt.-% 4.0 4.0 4.0

Water Wt.-% 28 26 25

Properties

Rheology

BF 0.5 rpm mPa·s 3,750,000 2,780,000 2,100,000

BF 5.0 rpm mPa·s 416,000 396,000 384,000

BF 50 rpm mPa·s 55,000 76,000 76,000

log (0.5 rpm) – log (50 rpm) 1.83 1.56 1.45

Slip mm 0.5 1.5 2.0


Standard N/mm2 1.25 1.32 1.45

20 min open time N/mm2 1.19 1.35 1.25

30 min open time N/mm2 0.69 0.72 0.75


Heat aging N/mm2 0.34 0.58 0.80

Table 3: Property profile of cellulose ethers in cement based tile adhesives

It was found that other, non water-soluble thickeners increasethe consistency of cement-based tile adhesives, without negative consequence on the tensile adhe-sion. Sheet-silicates and cellulosefibres are such products.

Results: Table 4 clearly demonstra-tes that it is possible to increase thewater demand of a tile adhesive for-

mulation with the aid of sheet silicates (Pangel S-9) or cellulosefibres (Arbocel BWW 40) withoutreducing the slip resistance. Evenmore important is the fact that thetensile adhesion does not deterio-rate by the addition of these typesof additives.

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Proceeding step by stepAlternative tickener systems


Steidle sand Wt.-% 60 60 60

CEM I 52.5 Wt.-% 40 40 40

METHOCEL 10-0350 Wt.-% 0.5 0.5 0.5

Pangel S-9 3) Wt.-% 0.5

Arbocell BWW 40 Wt.-% 0.5

DLP 2000 Wt.-% 2.0 2.0 2.0

Water Wt.-% 28 32 32

Properties

Rheology

BF 0.5 rpm mPa·s 3,790,000 3,201,000 2,960,000

BF 5.0 rpm mPa·s 594,000 464,000 436,000

BF 50 rpm mPa·s 96,000 79,000 73,000

Slip mm 1.0 0.75 1.0


Standard N/mm2 1.19 1.31 1.20

20 min open time N/mm2 1.69 1.44 1.35

30 min open time N/mm2 1.27 1.10 1.28


Heat aging N/mm2 0.89 1.22 1.21

Table 4: Alternative thickeners for cement-based tile adhesives

3) Trademark – Grupo Tolsa, Madrid

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Results: Bentone GS, a hectoriteand Optibent CP, a bentonite, havenearly the same effect on the tensileadhesion properties. Optibent CPincreases the viscosity to a lesserdegree than Bentone GS.Attapulgites, such as Minugel 200increase the consistency, but theyhave a negative influence on tensileadhesion properties. In particular,

the open time and the adhesionafter the heat aging deteriorate.Pangel S9, a sepiolite has proven tobe most effective.The thickeningeffect is twice as efficient as hectorite or bentonite. In practicethis means that only half the dosagelevel is required to reach the sameviscosity.The tensile adhesion is not influenced and remains high.

Proceeding step by stepAlternative tickener systems



CEM I 42.5 Wt.-% 40 40 40 40

XCS 41120.00 Wt.-% 0.4 0.4 0.4 0.4

DLP 210 Wt.-% 4.0 4.0 4.0 4.0

Bentone GS Wt.-% 1.0

Minugel 200 4) Wt.-% 1.0

Optibent CP 5) Wt.-% 1.0

Pangel S-9 Wt.-% 0.5

Water Wt.-% 28 28 28 28

Properties

Rheology

BF 0.5 rpm mPa·s 3,600,000 3,974,000 2,690,000 3,290,000

BF 5.0 rpm mPa·s 528,000 598,000 478,000 440,000

BF 50 rpm mPa·s 93,000 100,000 85,000 77,000

Slip mm 1.0 1.0 1.0 0.5


20 min open time N/mm2 1.95 1.41 1.90 1.32

30 min open time N/mm2 0.99 0.48 1.07 0.94


Heat aging N/mm2 0.90 0.64 0.94 0.79

Table 5:The effects of different sheet silicates on the properties of a tile adhesive.

4) Trademark of ITC, Inc. Maryland, USA5) Trademark of Südchemie AG, Munich

Redispersible polymer powders arecrucial components of high qualitytile adhesive formulations.Theseadditives substantially increase thetensile adhesion and improve theflexibility of the adhesive link between the tile and the substrate.This feature is very important especially with difficult substrateslike wood, old tiles and when floorsare equipped with floor heating.Redispersible polymer powders alsoplay a key role in tile adhesives meeting EN 12004.

The figure below illustrates theeffect of two different polymer powders on the tensile adhesionproperties of a tile adhesive. Bothproducts are vinyl acetate/ethylenebased. However, DLP 2000 is a harder polymer with a higher glasstransition temperature than DLP 210.

Results: A rather simple base for-mulation with a low water demandwas used.This explains the relativelylow tensile adhesion values obtai-ned. However, the influence anincreased powder level has on theproperties in other formulations,can be estimated accordingly.Without addition of polymer pow-ders the tensile adhesion after heataging has almost completely collap-sed.The standard tensile adhesion,as well as the tensile adhesion afterheat aging, improves when the levelof polymer powder is increased.Thiseffect is more pronounced with DLP2000.

When cement of better quality isused or if other rheological additives(sheet silicates, cellulose fibres) areadded to increase the waterdemand it is possible to achieve tensile adhesion values with DLP

2000, which fulfill the requirementsof EN 12004/C2.

As demonstrated in the previoussimple formulation, here too inFigure 2 an increase in the polymerpowder addition level shows a clearimprovement in the standard tensile adhesion, as well as in the tensileadhesion after heat aging.Apparently, the addition level ofpolymer powder has no influenceon the tensile adhesion after waterimmersion. In this formulation theaddition of only 2% of DLP 2000 is sufficient to achieve a tensile adhesion of 1.0 N/mm2 after standard, wet and heat aging.Figure 3 shows the results of deformation measurements of curedadhesive strips according to EN12002. It is remarkable to see thatthe maximum transversal defor-mation more than doubles with the

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Proceeding step by stepRedispersible polymer powder

0.5

1

1.5

2

2.5

w/oDLP

2% 4% 6% 2% 4% 6%

Standard

Heat aging

Base formulation:

Zimmerli- Sand 60.00 Wt. – %CEM I 42.5 40.00 Wt. – %XCS 41120.00 0.45 Wt. – %Water 25.00 Wt. – %

Ten

sile

adh

esio

n, N

/mm

2

DLP 2000DLP 210

Water imm.

0

Figure 1: Comparison of two DLP products in a tile adhesive formulation at two addition levels.

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0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

Standard Water immersion Heat aging

1% DLP 2000

2% DLP 20003% DLP 2000

Base formulationSteidle sand 60.0 Wt. – %CEM I 52.5 40.0 Wt. – %XCS 41120.00 0.4 Wt. – %Bentone GS 1.0 Wt. – %Arbocell BWW40 1.5 Wt. – %

Ten

sile

adh

esio

n st

reng

th, [

N/m

m2 ]

Deformation (L)Force (F)

Base formulationZimmerli sand 60 Wt. – %CEM I 42.5 40 Wt. – %10-0366 0.45 Wt. – %Polymer powder 0-6 Wt. – %Water 25 Wt. – %

0% 2% 4% 6% 2% 4% 6%DLP 210 DLP 210 DLP 210 DLP 210 DLP 2000 DLP 2000 DLP 2000

Polymer powder type and addition level

Def

orm

atio

n (m

m)

Fo

rce

(N)

Deformation with different Polymer powders according to EN 1200210

5

0

Figure 2: Influence of addition level on tensile adhesion

Figure 3: Maximum transversal deformation and maximum force of a tile adhesive formulation containing two different types of polymer powders

increasing polymer powder level,whereas the maximum forceremains at a similar level.

The performance with regard tomaximum deformation and force ofDLP 210 and DLP 2000 are verysimilar.

The choice of the optimum polymerpowder is important to the overallperformance of the tile adhesivesuch as open time, standard tensileadhesion, tensile adhesion after specified aging procedures, and rheological properties. Dependingon the property profile desired,

which also depends on the othercomponents of the formulation (e.g. sand, cement, cellulose ether),the redispersible polymer powdermust be carefully selected to fit the formulation.

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CEM 42.5 Wt.-% 40 40 40 40


10-0350 Wt.-% 0.5 0.5 0.5 0.5

Std.VA / E Type Wt.-% 3

DLP110 Wt.-% 3

DLP210 Wt.-% 3

DLP 2000 Wt.-% 3

Water Wt.-% 28 28 28 28

Properties

Density kg/m3 1543 1462 1500 1537

Rheology

BF 0.5 rpm mPa·s 3,132,000 3,713,000 3,324,000 3,587,000

BF 5 rpm mPa·s 445,000 457,000 453,000 467,000

BF 50 rpm mPa·s 71,000 77,000 74,000 75,000

Slip mm 1.2 1.5 1.6 1.0


Standard N/mm2 1.21 1.47 1.04 1.20

10 min open time N/mm2 1.70 1.83 1.73 1.96

30 min open time N/mm2 1.54 1.18 1.38 1.92

Heat aging N/mm2 0.57 0.39 0.38 0.74


Application properties of different polymer powders

Table 6: Comparison of different polymer powders

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Table 6 shows the properties of different redispersible polymer powders in a standard tile adhesive formulation. DLP 110, a relativelyhard VA/VeoVa grade proves itsadvantage in the standard tensileadhesion and in the tensile adhesionafter water immersion.The tensileadhesion after 30 min open time islower compared with other polymers.VA/VeoVa polymers tendto show skin formation after a longer open time.

The standard VA/E copolymer showsa balanced standard tensile strengthand open time properties. However

the tensile strength after waterimmersion is lower (0.18 N/mm2)compared with all other polymersused.The tensile strength of DLP210 is somewhat lower after heataging compared to the Std.VA/Ecopolymer.After the water immer-sion, however, it is clearly better(0.67 N/mm2).The medium hard DLP 2000 shows a very balancedperformance between standard tensile adhesion, open time andadhesion after heat aging and waterimmersion. It outperforms all otherpolymers tested in most of the properties.


Identification Polymer base Flexibility Tg (C) MFT

Std.VA / E type Wt.-% VA/E Hard 17 0

DLP 110 Wt.-% VA/Veova Hard 22 4

DLP 210 Wt.-% VA/E Soft 6 0

DLP 2000 Wt.-% VA/E Medium hard 17 3

VA: Vinyl acetate E: Ethylene VeoVa: Vinyl ester of versatic acid

The test results obtained do notonly depend on the composition ofthe tile adhesive, but also on thequality of the substrate, namely theconcrete slabs and the tiles ontowhich the adhesive is applied.Thequality of the concrete slabsdepends on various parameters like the nature of the surface, theabsorption behaviour and the thermal expansion coefficient.

EN 1323 specifies water absorptionlimits of 0.5 – 1.5 ml within the first

4 hours. For practical and econo-mical reasons, commercially availableconcrete slabs are used for testing.Slabs fulfilling EN 1323 requirementsare not available at reasonable cost.For the study, we had two qualitiesof concrete slab at our disposal.Neither of the slabs fulfills the EN

1323 requirement of 0.5 – 1.5 mlwater absorption. Slab A absorbssubstantially more water, whereasslab B absorbs practically no water.This behaviour has serious conse-quences for the tensile adhesionresults obtained, as the followingtable demonstrates.

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Proceeding step by stepConcrete slabs and tiles


Concrete slab A B A B

CEM 42.5 Wt.-% 40 40 40 40

Zimmerli sand Wt.-% 60 60 60 60

METHOCEL 345 Wt.-% 0.5 0.5

10-0350 Wt.-% 0.5 0.5

DLP 210 Wt.-% 2 2

Water Wt.-% 28 28 28 28

Properties

Rheology

BF 0.5 rpm mPa·s 2,112,000 2,112,000 3,511,000 3,511,000

BF 5 rpm mPa·s 465,000 465,000 447,000 447,000

BF 50 rpm mPa·s 101,000 101,000 71,000 71,000


10 min open time N/mm2 1.08 1.56 1.06 1.49

30 min open time N/mm2 0.10 0.36 0.92 1.45

Heat aging N/mm2 0.10 0.80 0.43 0.94


Water absorption according

to EN 1323

Slab A 2.0 – 3.5 ml

Slab B 0.05 – 0.20 ml

Table 7: Tensile adhesion strength obtained with two types of concrete slabs

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Results: The tensile adhesionresults obtained with the moreabsorbing concrete slabs (A) are inthis case lower than with the lessabsorbing concrete slabs (B). Onlythe values obtained after the waterimmersion remain independent ofwater absorption.The largest difference in the results obtainedwith the two different slabs was intensile adhesion strength after heataging, where values varied by a factor of two to eight. Hence a correlation between water absorp-tion and tensile adhesion strengthcould be established.

The difference in the results obtai-ned after 10 and 30 minutes open

time can be explained by the lack ofwater retention.The adhesive applied onto the more absorbentconcrete slab dries out more untilthe tile is inserted.The differencesobtained after heat aging are difficult to estimate and are there-fore the subject of further investiga-tion.The test results of formulation30/31 demonstrates that the C1 classification can also be metwithout redispersible polymer pow-der depending on the substrateused (heat aging value).

In all our studies we used concreteslab type A. Even though it does notmeet the EN 1323 requirements,the slab yielded reproducible results.

The fact, that the results with theseslabs were lower, only indicatestougher test conditions, whichshould not diminish the quality ofthe work described.

The quality of the tiles influencesthe performance of a tile adhesive ina similar way to that already seenwith the concrete slabs. In the following table the influence of fully vitrified tiles and porous tiles (fromtwo different tile producers), on thetensile adhesion, is demonstrated.The data show the influence of different tile types on the adhesionperformance using two different tileadhesive formulations.A rather simple tile adhesive formulation


Components Form 34 Form 35 Form 36 Form 37 Form 38 Form 39

CEM 42.5 Wt.-% 40 40 40 40 40 40

Steidle sand Wt.-% 60 60 60 60 60 60

METHOCEL 267 Wt.-% 0.5 0.5 0.5

METHOCEL 10-0350 Wt.-% 0.5 0.5 0.5

Water Wt.-% 30 30 30 30 30 30

Tile type:

Porous tile, EN 159 X X

Fully vitrified French tile, EN 176 X X

Fully vitrified German tile, EN 176 X X

Properties


10 min open time N/mm2 1.32 0.91 1.16 1.34 0.93 1.09

30 min open time N/mm2 0.54 0.39 0.62 0.70 0.52 0.67

Heat aging N/mm2 0.46 0.07 0.11 0.38 0.00 0.03

Water immersion N/mm2 1.15 0.70 1.16 1.07 0.67 1.08

Table 8: Comparison of different tiles

based on CEM I 42.5 and two different types of cellulose etherwere compared. None of these for-mulations contain polymer powder.

The influence of tile quality on adhe-sion was most pronounced afterheat aging.The tensile adhesionobtained with the porous tile was0.46 N/mm2 and 0.38 N/mm2, whereas a tensile adhesion of only 0.07N/mm2 was obtained with the fullyvitrified (EN 176) tile from France.Tensile adhesion using the secondformulation was totally lost.

The fully vitrified German tile (EN176), showed only marginally betterperformance after the heat aging.However, the open time and thetensile adhesion after water immer-sion with this tile were similar tothe results of the porous tile andclearly better than the results obtai-ned with the fully vitrified Frenchtile.This demonstrates that differentadhesion performance results can beobtained with different tiles, meetingthe same norm (EN 176).Why suchdifferences arise may depend, forinstance, on the porosity, surfacenature, or on the thermal behaviour.In order to keep conditions con-stant we only used the French fullyvitrified tiles for all our studiesaccording to EN 1348.

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The purpose of this part of thestudy was to optimise tile adhesiveformulations to meet a C1T/C2TE classification as cost effectively as possible.With the help of a com-puter aided experimental designsoftware program (JMP) the influence of the following parame-ters were investigated: nominalviscosity of the cellulose ether,degree of modification as well asaddition level of cellulose ether and polymer powder.

Results:The results from this evaluation allow the following con-clusions, which could be specific tothe raw materials used (Steidle sand,CEM I 52.5):

The low viscosity cellulose ether(4000 mPa·s) has an advantage inopen time, where the tensile adhe-sion was more than 40% higher.A cellulose ether concentration of0.4% also yielded improved adhesionafter heat aging (+15%).

A medium to strong modification of the cellulose ether improves theopen time particularly.The latteralso has a strong influence on thewater demand, which can be increased by 3% whilst maintainingthe slip resistance.The additionlevel of DLP 2000 has a greatinfluence on the adhesion resultsafter heat aging.

Development of formulations for the EN 12004 classification

FormulationparametersAdhesivesproperties

Water demand

Standard adhesion

20 min opentime

30 min opentime

Heat aging

Waterimmersion

CE-Viscosity CE-Dosage CE-Modification

DLP 2000Dosage

Impact of formulations parameters on the properties of the tile adhesive:

Table 9: Dependence of the variables as calculated by JMP

The water level can also be reducedby 1% with every additional 1% ofDLP 2000 whilst maintaining thesame slip resistance.

As a result of the experimentaldesign an optimum formulation(Table10, Formulation 40), can bedeveloped meeting the C1T classifi-cation e.g. <0.5 mm slip, 0.5 N/mm2

tensile adhesion strength after allaging procedures. Even the optionalrequirement for prolonged opentime is achieved (0.5 N/mm2 after 30 minutes).Analogous to the development of a C1T formulation,a further formulation for C2TE isshown in Table 10, Formulation 41,where 1.0 N/mm2 tensile adhesionstrength after aging procedures aswell as 0.5 N/mm2 after 30 min.open time have to be met.With theexception of the tensile adhesionafter the water immersion, therequirements can be met with theaddition of only 3% DLP 2000.Formulation 42 meets the C2TEclassification with a higher modifiedcellulose ether XCS 41405.00.Thisis possible at an elevated water levelof 30% with only 2% of redispersiblepolymer powder.Cellulose ether XCS 41406.00 isused in formulation 43 which meetsthe C2TE classification at a waterlevel of 32%.

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19


CEM 52.5 Wt.-% 40 40

CEM 52.5 Milke Wt.-% 40 40


Cellulose ether XCS 41142.00 Wt.-% 0.4

Cellulose ether XCS 41403.00 Wt. -% 0.5



Degree of modification Medium Medium Medium-high High

DLP 2000 1 3 2 3

Water Wt.-% 27 27 30 32

Properties

Density kg/m3 1510 1544 1580 1650

Rheology

BF 0.5 rpm mPa·s 2,905,000 4,318,000 3,206,000 2,985,000

BF 5 rpm mPa·s 445,000 875,000 544,500 352,000

BF 50 rpm mPa·s 82,000 141,000 79,000 49,000

Slip mm 0.5 0.5 0.5 0.5


Standard N/mm2 0.92 1.26 1.16 1.37

20 min open time N/mm2 1.44 1.17 0.98 1.64

30 min open time N/mm2 0.85 0.53 0.99 1.56

Heat aging N/mm2 0.52 1.17 1.13 1.04


meeting EN 12004 classifications C1T C1TE+ C2TE C2TE

Table 10: Formulations of three experimental designs


20

Cement

Raw materials

Experimental

Identification Classification Manufacturer

Normo 4 CEM I 42.5 HCB Siggental, Switzerland

Normo 5 CEM I 52.5 HCB Siggental, Switzerland

Milke cement CEM I 52.5 R Milke Geske, Germany

Zimmerli Sand

Specific surface: <0.1 m2/g

Volume % Particle size [µm]

10 130

40 180

40 230

10 280

Steidle Sand

Specific surface: 2.885 m2/g

Volume % Particle size [µm]

15 80

10 110

10 140

15 80

20 230

20 280

10 360

Identification Viscosity [Brookfield RVT, 20 rpm, 2% soln. ] Degree of modification

METHOCEL 10-0356, cellulose ether 10,000 mPa·s High

METHOCEL 10-0350, cellulose ether 10,000 mPa·s Medium-high

METHOCEL 10-0366, cellulose ether 10,000 mPa·s Low

Exp. cellulose ether XCS 41120.00 7,000 mPa·s Low

Exp. cellulose ether XCS 41142.00 4,000 mPa·s Medium

Exp. cellulose ether XCS 41403.00 4,000 mPa·s Medium

Exp. cellulose ether XCS 41405.00 4,000 mPa·s Medium-high

Exp. cellulose ether XCS 41406.00 4,000 mPa·s High

Identification Polymer Bulk density [g/dm3] Ash content [%] MFT [°C] Tg [°C]

DLP 210 PVAc/E 425 10 0 6

DLP 2000 PVAc/E 450 10 2 17

DLP 110 PVAc/VeoVa 450 10 4 22

Cellulose ethers (typical product properties)

Redispersible polymer powder (typical product properties)

Sand

21

Sheet silicate

Experimental

Identification Mineralogical description Manufacturer

Pangel S-9 Sepiolite Grupo Tolsa, Madrid

Bentone GS Hectorite Rheox Europe S.A., Bruxelles

Optibent CP Bentonite Süd-Chemie AG, Munich

Minugel 200 Attapulgite ITC, Inc., Maryland, USA

Identification Manufacturer Fibre length [(m] Fibre diameter [µm]

Arbocell BWW 40 J. Rettenmaier & Söhne 200 20

Identification Manufacturer/Supplier Dimensions [m] Water absorption

l x w x t EN1323

Concrete flagstones Antoniazzi, Italy 0.4 x 0.4 x 0.04 0.05 – 0.20 ml

Concrete flagstones Baubedarf, Horgen 0.5 x 0.25 x 0.04 2.00 – 3.50 ml

Identification Manufacturer/Supplier Dimensions [mm] Standard

Ostara Laufen Ostara 50 x 50 x 5 cut EN 159

Uni blanc Winckelmans 50 x 50 x 5 EN 176

Villeroy Boch 47 x 47 x 3 EN 176

Cellulose fibre

Concrete slabs

Tiles

22

Slip fully vitrified tiles (EN 176) 100x100 mm;EN 1308 200g loaded with 50 N for 30 seconds

slip determined after 20 minutes

Open time porous tiles (EN159) 50x50 mm loadedEN 1346 with 20 N for 30 seconds; insertion time

after 10, 20, and 30 minutes tensile adhesion test after 28 days; the insertion time at which the tensile adhesion still exceeds 0.5 N/mm2 is determined

Tensile fully vitrified tiles (EN 176) 50x50 mm adhesion loaded with 20 N for 30 seconds;EN 1348 insertion time within 5 minutes after

mortar application determination of the tensile adhesion strength after 28 days

Water fully vitrified tiles (EN 176) 50 x 50 mm immersion loaded with 20 N for 30 seconds;EN 1348 insertion time within 5 minutes after

mortar application determination of the tensile adhesion strength after 7 days standard climate and 20 days water immersion

Heat aging fully vitrified tiles (EN 176) 50 x 50 mm EN 1348 loaded with 20 N for 30 seconds;

insertion time within 5 minutes after mortar application determination of the tensile adhesion strength after 14 days standard climate and 14 days at 70°C

Transverse determination of the transverse defor-deformation mation of tile adhesives and grouts:EN 12002 The maximum deflection and the maxi

mum stress of a (280 x 45 x 3mm) mortar strip is determined after curing for 14 days in a polyethylene bag and 14 days at standard climate conditions

Consistency measurement

A Brookfield Viscometer equipped with a Helipath spindle was used todetermine the consistency (viscosity) of the liquid tile adhesive mortar.The consistency was measured at three shear rates (0.5, 5.0 and 50 rpm).In addition to rotating, the spindle oscillated up and down, to avoid shearaging of the liquid mortar.

Testing of all adhesive formulations were carried out according to the Euro-Norm:

Test methods

Form No. 177-01632-0102CH 151-216-E-0102*Trademark of The Dow Chemical Company

Notice: No freedom from any patent owned by Seller or others is to be inferred. Because use conditions and applicable laws may differ from one location to another and may change with time, Customer is responsible for determining whether products and the information in this document are appropriate for Customer’s use and for ensuring that Customer’s workplace and disposal practices are in compliance with applicable laws and other governmental enactments. Seller assumes no obligation or liability for the information in this document. NO WARRANTIES ARE GIVEN; ALL IMPLIEDWARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY EXCLUDED.

For more information about METHOCEL cellulose ethers and DLP redispersible polymer powders contact DOW at:Telephone: international +800 3694 63 67, Fax: international +32 34 50 28 15

Website: www.methocel.com, email: [email protected]

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en-12004 impac on adhesive formulations.pdf

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