CH627765A5 - Process for the preparation of finely divided polymer dispersions - Google Patents

Description

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PATENT CLAIMS can be cleaned with water. But above all are with soches

Dispersions with high molecular weight of the binder

1. Process for the production of fine-particle plastic di- high solids contents possible without unacceptably high spersions, which have to be accepted for the solidifying priming of paint viscosities. In addition, it is particularly suitable to polymerize a dry residue of water from a paint film more easily than a mixture of unsaturated monomers, thereby known solvent residues. Finally, plastic dispersions that a mixture of nen, provided that their emulsifier-protective colloid systems a) are 20 to 80 wt .-% styrene or methyl methacrylate or compatible, can be mixed more versatile than solutions, such as a mixture of styrene and Methyl methacrylate as hardness- that the property profile can be varied by mixing different dispersing components, 10 sions.

b) 20 to 80 wt .-% of an ester of acrylic acid with a Despite the obvious advantages, aqueous systems straight-chain or branched alcohol with 2 to 8 carbon have not been able to introduce themselves as a primer. Water atoms or an ester of methacrylic acid with a straight-soluble binder penetrate deeply into the substrate, but chain or branched alcohol with 4 to 8 carbon atoms are not sufficiently waterproof and / or saponifiable or a mixture of the esters mentioned as a soft 15 bil. Plastic dispersions give water if the correct component, monomers and the emulsifier protective colloid system are selected correctly.

c) 0.1 to 5% by weight of an amide of a, β-unsaturated and saponification-resistant paints, their penetration depth is sufficient for carboxylic acid and, above all, for solidifying and blocking off the substrate

d) 0.1 to 5% by weight of a, β-unsaturated monocarboxylic acid which does not consist of. As by polymerizing optically brightening

whereby the total amount of the monomers c) and d) 0.2 to 8.5 20 lending monomers could be determined, penetrate the

% By weight, as such or in the form of an aqueous dispersion used hitherto because of its large average

Preemulsion simultaneously with an initiator in an aqueous particle diameter hardly in cavities and capillaries of the

Liquor which contains 0.5 to 10% by weight of an anionic emulsifier substrate and essentially forms only one film, is metered and polymerized therein, the surface of which is mentioned.

ten monomers are used in such an amount that the two-stage process from DE-PS1 925 353 does not know a solids content of the finished dispersion of 45% by weight, according to which vinyl ester copolymer dispersions also increase, and the pH of the dispersion obtained, the particle sizes of which are smaller than 0.2 (x. The polymer particles therein have an average particle size of 0.01 to 0.06 (but in the polymers described are not sufficiently watery, set to 7 to 10 and stable to saponification, and the two-stage manufacturing process

2. The method according to claim 1, characterized in that 30 is complicated.

one as monomer b) ethyl acrylate, propyl acrylate, isopropyl acrylate. It has now been found that finely divided plastic

lat, butyl acrylate, 2-ethylhexyl acrylate, butyl methacrylate or 2- dispersions, which are used for the solidifying primer of paint

Ethylhexyl methacrylate used. Substrates are particularly suitable by polymerizing

3. The method according to claim 1, characterized in that a mixture of unsaturated monomers can be prepared by using acrylamide or methacrylamide as monomer c). 35 by making a mixture of

4. The method according to claim 1, characterized in that a) 20 to 80 wt .-% styrene or methyl methacrylate or as a monomer d) acrylic acid or methacrylic acid, a mixture of styrene and methyl methacrylate is used as hard. appropriate component,

5. The method according to claim 1, characterized in that b) 20 to 80 wt .-% of an ester of acrylic acid with a solids content of the dispersion to 20 to 45 wt .-% 40 straight-chain or branched alcohol with 2 to 8 carbon. atoms or an ester of methacrylic acid with a straight

6. The method according to claim 1, characterized in that chain or branched alcohol with 4 to 8 carbon atoms, the pH of the dispersion is adjusted to 7.5 to 9. or a mixture of the esters mentioned as soft

7. The method according to claim 1, characterized in that the component,

the aqueous liquor contains 20 to 50% by weight of the anionic emulsifier 45 c) 0.1 to 5% by weight of an amide of an α, β-unsaturated and the pre-emulsion the remaining part. Carboxylic acid and d) 0.15 to 5% by weight of an oct, β-unsaturated monocarboxylic acid,

the total amount of monomers c) and d) 0.2 to 8.5

% By weight, as such or in the form of an aqueous

Primer for the solidifying preparation of pre-emulsion 50 simultaneously with an initiator in an aqueous

Line substrates essentially have to meet the following requirements, which meet 0.5 to 10% by weight of an anionic emulsifier: contains, metered and polymerized therein, the specified

The binder must penetrate deep into the substrate, use monomers in such an amount that it solidifies well after drying and its absorbency does not reduce the solids content of the finished dispersion by 45% by weight. The primer must have a good primer for 55, and the pH of the dispersion obtained, the subsequent coats of which form. It must be resistant to water, Versei- polymer particles, an average particle size of 0.01 to 0.06 [xm fung and atmospheric influences. Have solvents, set to 7 to 10.

primers containing tel, which so far alone meet these requirements. The plastic dispersions obtained are water-resistant and fair, have various disadvantages. The content of saponification-resistant, deeply penetrating primers. Solvents are physiological and because of the risk of fire 60 The choice of monomers is of concern to those skilled in the art. The implement must be cleaned with solvents and follow known rules so that stable dispersions are formed.

will. The molecular weight of the binders is limited, and that the film-forming temperatures of the copolymers because the viscosity of the primers at high molecular weight in the areas known to be favorable for painting technology

too high or no high concentrations will be high, so expediently between - 10 ° C and + 25 ° C. allow. 65 As a hardening component it is particularly advantageous

In contrast, aqueous plastic dispersions only use styrene.

essential advantages. They contain no flammable or phy- Examples of the softening component are ethyl

Siologically questionable solvents. The implement can be acrylate, propyl acrylate, isopropyl acrylate and the acrylic or

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Methacrylic acid ester of butyl alcohol and 2-ethylhexyl alcohol.

Amides of α, β-unsaturated carboxylic acids, in particular acrylamide or methacrylamide, support the formation of finely divided dispersions if they are added to the batch together with the other monomers during the polymerization 5, which is why it is a preferred embodiment of the invention, 0.1 up to 5% by weight and in particular 1.5 to 3.5% by weight of acrylamide or methacrylamide, based on the total amount of the monomers, to be used as comonomers. io

The incorporation of <x, β-unsaturated monocarboxylic acids into the copolymer increases the stability of the dispersion during production, storage and use. Acrylic acid and methacrylic acid in amounts of 0.1 to 5% by weight, based on the total amount of monomers, are preferred examples. 15

On the other hand, it must be taken into account that the amides of group c) and the carboxylic acids of group d) as hydrophilic monomers increase the hydrophilicity of the whole molecule. In order not to unduly lower the water resistance of the primers and paints 20 produced with the dispersions obtained according to the invention, the total content of the monomers mentioned should be 0.2 to 8.5% by weight. Within these limits, the higher the content of hydrophobic monomers in groups a) and b), the higher the upper limit of the range from 0.2 25 to 8.5% by weight, if the the other monomers are particularly hydrophobic, such as. B. styrene, butyl acrylate, 2-ethylhexyl acrylate or 2-ethylhexyl methacrylate, and at the lower limit if the other monomers are less hydrophobic, such as. B. methyl methacrylate and ethyl acrylate. 30th

Only styrene is preferably used as the group I hardening monomer.

Examples of suitable monomer combinations are (parts by weight):

Butyl acrylate styrene acrylic and / or methacrylic acid acrylic 35 and / or methacrylamide (40 to 80/60 to 15 / 0.1 to 4 / 0.1 to 4).

2-ethylhexyl acrylate-styrene-acrylic and / or methacrylic acid-acrylic and / or methacrylamide (30 to 80/65 to 15 / 0.1 to 4 / 0.1 to 4).

2-ethylhexyl acrylate-methyl methacrylate-acrylic and / or 40 methacrylic acid-acrylic and / or methacrylamide (30 to 80/65 to 15 / 0.1 to 4 / 0.1 to 4).

Butyl acrylate-methyl methacrylate-acrylic and / or methacrylic acid * Acrylic and / or methacrylamide (40 to 80/55 to 15 / 0.1 to 3 / 0.1 to 3). 45

The polymerization must take place in the presence of an anionic emulsifier. Anionic emulsifiers which can be used are, for example, the alkali salts of sulfuric acid half-esters, alkylphenols or alcohols, furthermore the sulfuric acid half-esters of oxyethylated alkylphenols or 50 alcohols or else alkyl or aryl sulfonate. Examples of these anionic emulsifiers are the alkali metal salts of the sulfuric acid half-ester of a nonylphenol reacted with 4 to 5 moles of ethylene oxide, sodium lauryl sulfate, sodium lauryl ethoxylate sulfate which contains 2 to 5 moles of ethylene oxide, sodium dodecylbenzene 55 sulfonate and secondary sodium alkane sulfonate 20, the carbon chain 8-bisulfonates of which carbon-8-bisphenol carbonate Has.

The amount of anionic emulsifiers is 0.5 to 10% by weight, based on the total monomers, preferably 2 to 8% by weight. An increase in the amount of the anionic emulsifier used generally leads to a reduction in the particle size.

Furthermore, in order to increase the stability of the dispersions, nonionic emulsifiers of the ethoxylated alkylphenol or fatty alcohol type, e.g. B. nonylphenols with 4 to 30 65 mol of ethylene oxide in a mixture with the anionic emulsifier. When selecting the emulators, monomers used for the production and the production process used, care must be taken to ensure that dispersions are formed which do not tend to form aggregates either after production or after the process with water. When using the finely divided plastic dispersions for impregnation and priming, the formation of larger aggregates can reduce the penetration.

Suitable initiators are the usual inorganic per compounds such as ammonium persulfate, potassium persulfate, sodium perphosphate and organic peroxides, such as. B. benzoyl peroxide, organic peresters such as perisopivalate, e.g. T. used in combination with reducing agents such as sodium disulfite, hydrazine, hydroxylamine and catalytic amounts of accelerators such as iron, cobalt, cerium and vanadyl salts, preferably alkali or ammonium peroxydisulfates.

The polymerization temperature can be between +10 and + 100 ° C, preferably between + 30 and + 90 ° C.

The solids content of the dispersions is advantageously between 20 and 45% by weight after production.

For the production according to the invention of the particularly fine-particle dispersions according to the invention, it is advantageous if polymerization is carried out at a low solids concentration. The reduction in the solids concentration generally leads to finely divided dispersions. As can be seen from Table 1, latices with coarser particles have a lower penetration capacity and a lower solidifying effect than the finely divided dispersions produced according to the invention. If finely divided dispersions contain a proportion of coarser particles due to a broad particle size distribution, this proportion does not contribute to the good penetration nor to a solidifying effect. Plastic dispersions with a narrow particle size distribution are therefore preferred.

After the end of the polymerization, the finely divided plastic dispersions are adjusted to pH = 7-10, preferably to 7.5-9, for example with alkali, ammonia or amines. In the case of the dispersions which are obtained with a low solids content, it is possible to set the solids content to higher values by vacuum distillation without impairing the extreme fine particle size of the dispersions.

The polymerization can e.g. B. can be carried out in such a way that 30-50 wt .-% of the water with 20-50 wt .-% of the nonionic emulsifier is introduced and a pre-emulsion is prepared from the monomers, the remaining part of the water and the remaining emulsifiers the liquor heated to 50-90 ° C. is metered in over 1-3 hours.

The quantitative ratio between monomers and water is selected so that the resulting dispersion generally contains 20-45% by weight of solids.

The amount of anionic emulsifier is advantageously 2 to 8%, based on the monomers, depending on the solids content selected.

The reaction mixture is stirred and the initiator is introduced in 1-5% aqueous solution in parallel with the emulsion metering. After the end of the feed, the entire batch is stirred for a further 1-3 hours at 70-90 ° C. The pH is then expediently adjusted to 7.5 to 9 using ammonia, aliphatic amines or alkali metal hydroxides.

The metering in of emulsions is not a mandatory requirement for the production of the finely divided dispersions, since finely divided plastic dispersions can also be obtained when the monomer mixture is metered into a liquor which contains all the water and the emulsifiers. When using plastic dispersions for primers and impregnations, the solids content of the dispersions has a significant influence on the depth of penetration, the strength of the hardening effect and on the reduction of the surfaces.

"'-rdüc.-t« r dri-:' er into the pores of the

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Substrate as a concentrated. In addition to the method of copolymerizing fluorescent centered dispersions, only a part of the latex particles penetrate into substances that under UV light accurately penetrate the pores, the Rèst forms a film on the surface. This depth of penetration of the polymer enables other metho-related effects that are known through the use of concentrated dispersers. Z. B. the fanning of the cross-sections the absorbency of the substrate through the treatment 5 cut surface of primed or impregnated substrates very strongly when using dilute dispersions with a Bunsen burner, whereby the polymer is reduced by very little. indicates a gray color. On acid-insoluble substrates

The strengthening effect depends not only on the nature of the coating of the cross-sectional areas with concentrated polymer, but also on the polymer content per volume of sulfuric acid used to identify the penetrated unit in the treated surface. Very highly diluted io polymers possible. These investigations showed that, although dispersions have a high penetration depth, the plastic content, with the same solids content, is finely divided, but the material content according to the invention per unit volume is relatively low. In the case of prepared plastic dispersions, the same penetration depths centered dispersions, the part of the polymer which had and solidifying effect, as the known binders remain on the surface after drying, does not contribute to the deep primer in solvent and that the

Consolidation of deeper layers. 15 penetration depth with a good solidifying effect much larger

From this information it can be seen that the choice of the particle size diameters of> 0.06 [im. of the relationship between depth of penetration, solidification and hardening. The superiority of the dispersions in the particle size finish of the surface, as well as a matching to the different values of <0.06 jxm, was particularly evident in the fact that it is also possible with substrates that occur in practice . With 20 relatively high solids contents, in which the dispersions produced in accordance with the invention are produced in a single operation, in which a large amount of plastic per unit area is usually good results can be achieved with solids contents between 5 and 25 - e.g. B. in the range of 15 to 20 wt .-% wt .-% and preferably between 10 and 20 wt .-%. It solids content - the very finely divided dispersions is still almost an advantage of the dispersions produced according to the invention, penetrate completely into the substrate and there for consolidation that in a relatively wide concentration range 25 and for better anchoring of subsequent coats contribute both good penetration depths and good consolidation by means of coarser ones For the most part, dispersions do not penetrate into the treated surface in a high specific plastic content and the surface can only be cleaned in a particularly favorable manner if the films form.

Latex particles in the range of an average particle size of 0.01 In addition, in a further test method there is the possibility of up to 0.06 (lying (determination of the particle size according to the 30th, by the action of the light scattering method according to the invention and electron microscopy). As with fine-particle dispersions on fine-grained , Loose material not common to the dispersion paints, auxiliaries can only be added to the penetration depth, but also with a certain one. Of the many known possibilities, the amount of binding agent achievable strengthening effect is to be studied - just a few are mentioned here as an example: ren that the material is in the area of his

Solvents for the improvement of the film formation and for the 55 penetration after drying leads to a bond of the granular lowering of the film formation temperature, plasticizer, material. The solidified core can be easily removed from the foam, preservatives, surface-active substances and weighed. The weight is a measure of the penetration and the strengthening effect for better wetting and pigments or soluble dyes. Through this for staining. Test is e.g. B. the solidification of the surface of old,

The penetration test can be simulated on various 40 weathered components.

Species success. Sokannz. B. the material to be tested on the To carry out the test, the quartz powder W6 of the selected substrate, e.g. B. by brushing, casting or quartz works GmbH, 5 Cologne-Marienburg (average analysis: dripping is applied. After drying, 50% <40 jxm) is used, which in a flat cross section identifies the penetrated material in flat containers. At was. At the feed point of the material to be tested, the use of dissolved resins offers the coloring 45 a hemispherical depression of 2.5 cm in diameter with soluble dyes. This method can lead to incorrect results when pressing a correspondingly shaped stamp on a dispersion basis if it produces. In this well 2 ml of the aqueous phase to be tested is also colored. Because dripped in most dispersion. After four hours of drying time, the aqueous phase penetrates deeper than the latex particles, room temperature, the described fill was still for here says the colored zone initially nothing about 50 15 hours at 50 ° C in the drying cabinet.

actual penetration of the latex particles. The results of these tests are summarized in Table 1

Detected to demonstrate the improved depth effect. Suitable dispersions prepared according to the invention were tested by copoly-plastic dispersions, the particle size of which lies between merization with vinylsulfonylpyrazoline brighteners in a concentration of 0.01 and 0.06 μm and which, according to Examples 1 to 7, is 0.01-0 , 05% by weight (based on monomers) were produced optically 55.

lightened copolymer dispersions are obtained, which contain the brightener molecules statistically as a component of the polymer sizes D> 0.08 μm on the basis of various monomer chains distributed over the macromolecule as a comparison material. The optical steme (Comparative Examples A, B, C) and commercially available Polyme brighteners can therefore not be removed from the polymer by extraction (Comparative Examples D, E) in organic solvents, which are removed. Where the characteristic fluorescence of the 60 is recommended for deep primers.

optical brightener appears in the substrate under UV light, From the results it follows that the largest core weight and there is also the polymer. so that the best penetration, combined with good missed

The optically brightened, finely divided copolymer dispersing effect with the nes produced according to the invention were applied to a large number of substrates such as e.g. Wood-plate dispersions and with the polymer solutions in organic, sand-lime brick, gypsum board, lime plaster, cement plaster, filler 65 are achieved (Table 1).

putty knife, unglazed clay plates, gas concrete, brick, etc. The one with the aqueous plastic dispersions applied with larger ones, the dry samples observed under UV light, mean particle diameters (D> 0.1 [im) obtained and the high penetration depth at the cut surfaces measured. nisse are in all cases significantly worse than with the

5

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Finely divided dispersions produced according to the invention.

Another requirement that is applied to primers with a depth effect is that the subsequent coat applied to the primed substrate has good adhesion and is well anchored to the substrate via the primer. This requirement must also be met if, as a result of the different absorbency of the substrate, the subsequent coat is applied to layers of the primer material of different thickness after the primer has been applied several times. To test this requirement, approx. 12% finely divided dispersions produced according to the invention were coated three times with intermediate drying on asbestos-cement boards as the substrate. After three days of air drying, an emulsion paint was applied to this primer layer, which contained a styrene / butyl acrylate dispersion as a binder and was pigmented 1: 1.6 (dispersion to pigment filler mixture). A reinforcing fabric strip made of polyethylene terephthalate was embedded in the still fresh paint and, after the first coat had dried, was coated with the same color again.

When attempting to peel off the fabric strips, good adhesion of the primer to the substrate and good adhesion between the primer and the emulsion paint coating were found both in the dry state and when wet or redried. This applies both to the soft and hard binder films of the polymers according to Examples 1 to 7, which can be adjusted by the monomer ratio. In all cases, the fabric strip was pulled out of the emulsion paint coat without leaving the color on the substrate or the primer, leaving the fabric grid pattern.

The same results were obtained when cross-hatching on the dried emulsion paint coating, when attempting to peel off the emulsion paint film using adhesive tape over the cross-hatch squares. The paint layer was not torn out here either.

The process according to the invention for producing finely divided dispersions is explained in the following examples:

example 1

Teristic blue fluorescence, which also enables the detection of very small amounts of polymer in the various substrates. Gel permeation chromatographic fractionations have shown that the optical brightener 5 is incorporated evenly into the polymer, i. H. there are no enrichments in certain molecular weight ranges. The average particle size diameter of the optically brightened copolymer dispersion is 0.038 [im.

10th

Example 3

To a fleet of 680 GT water, 25 GT one sec. Sodium alkane sulfonate (C12-Qg) and 10 pbw of a reaction product of nonylphenol and 8-12 moles of ethylene oxide are metered out in a monomer mixture

Styrene 170 GT

Butyl acrylate 170 GT

Acrylamide 4 GT

Methacrylic acid 10 pbw

20 A solution of 2 pbw of ammonium persulfate in 40 pbw of water is used as the initiator.

The mean particle size diameter is 0.038 µm.

25th

Example 4

3600 GT 3600 GT 100 GT 250 GT 340 GT

180 GT 1000 GT

Out

Styrene 134 GT

Butyl acrylate 200 GT

Acrylamide 4.5 GT

Methacrylic acid 12.0 pbw

Sodium salt of a sec. Alkane sulfonate (C12-C16) 10 pbw reaction product of nonylphenol with 10-12 moles of ethylene oxide 5.0 pbw

Water 400 GT

a stable monomer emulsion is produced. The emulsion is metered into a liquor solution composed of 230 pbw of water, 2 pbw of nonionic emulsifier and 8 pbw of ionic emulsifier. A solution of 2 pbw of ammonium persulfate in 40 pbw of water is metered in parallel to the emulsion metering.

The mean particle size diameter of the dispersion adjusted to pH 8-9 is 0.036 [im.

Example 2

Optically brightened, finely divided copolymer dispersions are obtained if an additional 0.1 pbw of a vinylsulfonylpyrazoline brightener (see DOS 2 011 552) is dissolved in the monomer mixture according to Example 1 and then the plastic dispersion is prepared according to the instructions.

Both the aqueous plastic dispersion and the dry polymer film show a character of styrene under UV radiation

Butyl acrylate Acrylamide 30 methacrylic acid Sodium lauryl sulfate Reaction product from nonylphenol + 8-12 moles of ethylene oxide water

35 a stable monomer emulsion is produced. The emulsion is metered into a liquor solution composed of 5000 pbw of water, 80 pbw of the nonionic emulsifier and 280 pbw of the anionic emulsifier. At the same time, a solution of 40 pbw of ammonium persulfate in 900 pbw of 40 water is metered in parallel to the monomer emulsion. The mean particle size diameter of the dispersion adjusted to pH 8-9 is 0.042 [im.

In the same reaction vessel, the dispersion can be concentrated to a solids content of approx. 45% under a water jet vacuum. The mean particle size diameter remains unchanged at 0.042 (in.

Example 5

A monomer mixture of methyl methacrylate 130 parts by weight is metered into a fleet of 660 parts by weight of water, 20 parts by weight of sodium lauryl-50 ethoxylate sulfate (with 2-5 moles of ethylene oxide) and 8 parts by weight of a reaction product of nonylphenol + 6 to 10 parts by weight of ethylene oxide

Butyl acrylate 200 GT

55 acrylic acid 12 GT

Acrylamide 4 GT

A solution of 3 pbw of potassium persulfate in 30 pbw of water is used as the initiator.

The mean particle size diameter is 0.041 | xm.

60

Example 6

Fleet components according to Example 5. Monomer mixture of 65 methyl methacrylate butyl acrylate, acrylic acid, acrylamide

100 GT 230 GT 13 GT 5 GT

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6

2 pbw of potassium persulfate in 20 pbw of water are used as the initiator. The mean particle size diameter is 0.045 µm.

Example 7

Out

Styrene 170 GT

Butyl acrylate 170 GT

Lauryl sulfate Na 15 GT10

Reaction product from nonylphenol with 8-12 moles of ethylene oxide 5 pbw

Water 450 GT

a stable monomer emulsion is produced. The emulsion is metered into a liquor solution consisting of 200 pbw of water, 3 pbw of nonionic emulsifier and 8 pbw of ionic emulsifier. A solution of 3 pbw of ammonium persulfate in 30 pbw of water is metered in parallel to the emulsion metering. The mean particle size diameter of the dispersion adjusted to pH = 8-9 is 0.060 (im. 20

Comparative Example A

It becomes a copolymer dispersion made of vinyl acetate 70 GT25

VersaticR-10-acid vinyl ester 25 GT

Crotonic acid 5 GT

made with an anionic emulsifier and an inorganic per compound with a solids content of 40-50%. The mean particle size diameter is 0.620 [im.

Comparative Example B

A copolymer dispersion is prepared from vinyl acetate butyl acrylate as described in Example A. The mean particle size diameter is 0.270 [im.

Comparative Example C

It becomes a styrene copolymer dispersion

Butyl acrylate, acrylic acid, methacrylic acid, acrylamide with a mixture of anionic and nonionic emulsifiers and an inorganic per compound. The mean particle size diameter is 0.150 [im.

Comparative Example D

A copolymer of 70 GT vinyl acetate

Maleic acid dibutyl ester 30 GT

is dissolved 60% in ethyl acetate. The viscosity at 20 ° C according to Höppler (DIN 53 015) is 80 P.

A primer with a depth effect is produced from this solution in the following way: 60% copolymer solution in ethyl acetate 28 pbw

Shellsol AR 62 GT

Ethyl glycol acetate 10 pbw

Comparative Example E

From a copolymer of vinyl toluene 85 GT

Acrylic acid 2-ethylhexyl ester 15 pbw

that in 30% solution in xylene has a viscosity of approx. 60 cP at 20 ° C according to Höppler, a primer solution is prepared in the following way:

Copolymer 170 GT

White spirit 545 GT

Shellsol AR 285 GT

30th

example

70 GT35 30 GT

Table 1

Penetration attempts in quartz sand fillings

Core weight (g) after the addition of 2 ml of a 17% and 11% dispersion

Average particle size diameter (µm) (using the light scattering method)

40

50 GT 50 GT

2 GT45 5 GT

3 GT

50

1

0.036

12.3

13.6

2nd

0.038

11.8

12.5

3rd

0.038

12.1

12.8

4th

0.042

10.5

11.9

5

0.041

11.3

11.9

6

0.045

11.1

11.5

7

0.060

10.5

11.0

Comparative examples

A

0.620

0.6

1.1

B

0.270

3.4

3.8

C.

0.150

6.0

6.4

D

-

10.8

11.0

E

-

10.4

11.2