DE833856C - Process for the polymerization of vinyl and vinylidene chlorides - Google Patents

Description

(WiGBl. P. 175)

ISSUED MARCH 13, 1952

p 38462 IVcj 39c D

The invention relates to polymerization of vinyl chloride, vinylidene chloride and their mixtures alone or with small amounts of others compounds polymerizable therewith in aqueous dispersion, and its purpose is the production of polymers that are more resistant to discoloration and degradation by heat, while at the same time washing of the polymers previously required to remove the dispersant used Particles or granules become obsolete.

It is known that maintaining the state of dispersion of these monomers in one aqueous medium by means that change the surface tension, such as long-chain or alkylaromatic sulfonated hydrocarbons or sulfonated or sulfated fatty alcohols supported and that stable emulsions can be made if sufficient Amount of resource is used. Certain colloidal substances, such as glue, starch and polyvinyl alcohols, also exert a stabilizing effect on such dispersions, and the use these surface tension-changing auxiliaries and colloids as additives the polymerization and copolymerization of vinyl and vinylidene chlorides in aqueous dispersion has been suggested many times.

Although such dispersants are used in the manufacture of polymeric particles or granules Relatively uniform size can be advantageous, so is their presence in the polymer usually undesirable during subsequent processing and use, as they decompose during the heat treatment and

the polymer discolor and cloudy and reduce the heat resistance and the electrical Properties deteriorate. This behavior makes it necessary that they come from the polymer removed after it has been deposited from the aqueous medium, and in many Cases, especially when the polymer is obtained as a stable emulsion and with a coagulant must be treated, repeated lengthy washing may be required will. This results from the fact that the dispersants generally tend to at the To adhere to the surface of the polymer, and often they appear to be due to the action of a Coagulant to be converted into a relatively insoluble form.

Finding an effective dispersant for vinyl and vinylidene chlorides, their Polymerization or copolymerization is not impaired and that is compatible with the polymers and has no detrimental effect on them would therefore be of particular value.

It has now been found that partial esters of polyhydric alcohols with at most 10 hydroxyl groups in the molecule and fatty acids with at least 4 carbon atoms in the molecule not only these Meet demands, but also deliver products with improved properties when used as a Dispersants are used in amounts up to 5 percent by weight of the monomeric substance, so that their use valuable polymers directly from the aqueous polymerization medium, optionally after coagulation, without every ablution can be obtained.

The present invention therefore relates to a process for polymerizing vinyl chloride, Vinylidene chloride or mixtures thereof with or without small amounts of others polymerizable therewith Compounds in aqueous dispersion, which is characterized in that as a dispersing agent a partial ester from a polyhydric alcohol with a maximum of 10 hydroxyl groups in the molecule and a fatty acid with at least 4 carbon atoms in the molecule in an amount up to 5 g

CH ₂ OH -H ₂ O CH ₂ CHCH ₃ [Oh] CHOH HIGH CHOH CHOH -H ₂ O CHOH CHOH Hexitane CHOH CH ₂ OH HIGH CHOH
1 1 CH ₂ CH-CH C
\ O OH Hexit Hexitane

[weight percent of the monomeric product is used.

The minimum amount of the partial ester serving as a dispersant depends on its effectiveness generally 0.1 to 0.5 percent by weight, and it can easily be for a given Starting material can be determined by a small preliminary test. In the case of, for example Sorbitan laurate and caprate and similar substances 0.1 to 0.2 percent by weight will be sufficient while with glycol monobutyrate 0.4 to 0.5 percent by weight may be required.

The catalyst and any activating agents used, the temperatures and the proportions of the monomer to the aqueous phase can be those customarily used, and the catalyst can be monomer-soluble or water-soluble. If desired, an aliphatic alcohol can also be used, but the amount used should not be so great that the dispersing effect of the partial ester is negated or, in the case of lyophilic alcohols, that the mechanical properties of the polymer are impaired. There may also be present buffering agents and the _pH value _is controlled substances, and their use is particularly useful when the polymerization in the presence of metal, as for example, carried out in a vessel made of stainless steel.

The polyhydric alcohol can be a straight chain or a branched chain of acyclic structure or it can be alicyclic or an oxygen heteroatom contain. Examples of such partial esters are the aliphatic mono- and diglycerides, Ethylene glycol and diethylene glycol monoesters, the partial esters of erythritol and pentaerythritol and the monoesters obtained by partial dehydration from the hexitzucker alcohols Products, namely the Hexitane and Hexide or the Hexite or other sugar alcohols themselves.

The formation of hexitanes and hexides is illustrated by the following formulas, in which the edged hydroxyl group is esterified.

HIGH CH CH ₀

-H ₂ O

CH ₂ CH CH 0H |

Hexid

If desired, the remaining hydroxyl group or groups with at least ι mol of EthyLenoxyd are condensed, so that a corresponding side chain or chains of ethylene-5 oxide units are obtained with a terminal hydroxyl group. The well-known hexitan and hexide monoesters and the corresponding compounds with polyethylene oxide side chains be particularly suitable and are preferred

xo uses. These last-mentioned compounds contain the polyhydric hexitane and hexide alcohols a mixture of 5- and 6-membered heterocyclic ring compounds with 4 hydroxyl groups or a fused 5-membered heterodicyclic dioxy ring compound.

The dispersants used according to the invention can be prepared by known processes and the following are provided for illustrative purposes.

Glycerol monocaprate is produced by direct condensation of the theoretical amounts of capric acid and glycerol at 165 ° in the presence of p-toluenesulfonic acid as a catalyst.

Glycerol monobutyrate is used according to the in Jour.

At the. Chem. Soc. 1931, 53, 3481, method described by the action of sodium butyrate on α-glycerol monochlorohydrin, an 85% yield of the ester being obtained, * Bp. 134 ⁰ , N? i, 4515.

Pentaerythritdicaprat is obtained in 82 ° / cent yield by direct Sstündige esterification at 200 ⁰ mm under a pressure of 15 of Hg and subsequent extraction with carbon tetrachloride and filtration of the extract in order to remove any dipentaerythritol, and dilaurate can in the same way in 8o. ° / cent Yield can be produced. The monolaurate is obtained by esterification of the theoretical amounts of acid and alcohol in the presence of phenol as solvent and p-toluenesulfonic acid as catalyst at 200 ° within 4 hours in 65% yield and 80% purity.

Glycerol monoesterate, monolaurate and monooleate as well as diethylene glycol monooleate can each be condensed with, for example, 6 moles of ethylene oxide by heating 30 parts of the reactants with ι part of sodium methoxide for 44 hours in a closed stainless steel tube to 145 ⁰ , whereby water-soluble, syrupy or waxy products are obtained .

Since it is a feature of the present invention that ordinary washing is advantageous can be omitted, it is advisable not to add any other type of dispersant. The deposited polymer can, however, if desired, rinsed off somewhat with water to remove traces of ionic catalysts or activating auxiliaries such as persulfates and sulfites or buffering agents and the like, if they have been used. Such a rinse is of course from repeated washing with hot water or extraction with solvents, which were necessary in order to be | used dispersant to remove completely different.

In the dispersion there can also be monomeric substances or other compounds that help to maintain it do not contribute significantly to the dispersion, but are compatible with the polymer and do not have a deleterious effect on it and do not interfere with the polymerization. Such additives are, for example, various plasticizers and partial esters of polyvalent ones Alcohols and fatty acids with less than 4 carbon atoms.

The co-polymerizable compounds that can be incorporated in small amounts into the vinyl and / or vinylidene chlorides to be polymerized by the process according to the invention include, for example, acrylonitrile, methacrylonitrile and crotononitrile, the lower vinyl ketones, such as methyl and ethyl vinyl ketones, the esters of acrylic and methacrylic acid with aliphatic and cycloaliphatic alcohols with 6 or fewer carbon atoms, such as cyclohexyl methacrylate, methyl methacrylate and butyl acrylate, the diesters of itaconic, malcinic and fumaric acid with aliphatic and cycloaliphatic alcohols with b or fewer carbon atoms, such as dicyclohexyl fumarate and dicyclohexyl maleate , also vinyl fluoride and organic vinyl esters, such as vinyl acetate, vinyl methoxybutyrate and vinyl benzoate. Small amounts of such co-polymerizable compounds can be incorporated into the vinyl and / or vinylidene chloride and the mixture can then be polymerized in the manner described, so that valuable copolymers are obtained.

The method according to the invention is illustrated by the following examples. The catalyst concentrations, times, proportions and temperatures given in them can, however, be changed and other catalysts suitable for the dispersion polymerization of vinyl and / or vinylidene chloride can be used instead of those mentioned in practically equivalent amounts, the same results being obtained . In all cases in which press trials are given, the polymer or copolymer has been carried by mutual no soffit of 10 percent by weight of a plasticizer, such as α-α'-Diphenyldiäthyläther, plasticized and mm at 170 to 175 ⁰ through a bore diameter of 0.8 pressed and drawn so that a monofilament with a diameter of V ₂ mm was obtained. The term good strength means that the fiber was very difficult or impossible to break by hand.

Examples 1 and 2

2 parts of a mixture of vinylidene chloride and vinyl chloride in a weight ratio of 85:15 were per 66 hours at 45 ⁰ in a sealed tube with 0.4 percent by weight of o-chlorobenzoyl peroxide, 1.0 percent by weight of glycerol

monocaprat and water in an amount that a volume ratio of the monomeric substance to aqueous phase of 2.5: 1 or 1.5: 1 obtained was shaken. After this time the polymerization was practically complete, and so was the contents of the tube was filtered, whereby granular copolymers were obtained. The copolymers were then dried, plasticized and pressed without any washing, producing clear single threads good color and mechanical strength were obtained. During the pressing, the Mixed polymers have good flow properties.

Example 3

Contained an as-used in Example 1 mixture of vinyl and vinylidene chloride, 0.2 percent by weight of o-Chlorbenzoylperoxyd and 1 weight percent glycerol monocaprate, 45 hours at 50 ⁰ in a sealed tube with 2 volumes of io ° / o aqueous ethanol was shaken. After this time, the polymerization was practically complete, and the copolymer, when mixed and pressed as in Example 1, gave clear individual threads of good color and good mechanical strength.

Examples 4 and 5

Two of the most used in Example 3 same mixtures which, however, .berechnet on the monomeric material, 5 weight percent of glycerol monocaprate and no ethanol contained, were shaken in a sealed tube at 45 ⁰ 20 hours and 50 hours, whereby a degree of polymerization of 50 ⁰ / o or 95% was obtained. After the unreacted monomeric material had evaporated, the copolymers, as described in Example 1, were worked up and pressed. The product of Example 4, which corresponds to a 50 ⁰ / o polymerization, during the pressing had good flowability, good color, good heat stability, but only low fiber strength and

* 5 provided an opaque monofilament while the product of Example 5 has a clear monofilament of good color and high strength revealed. In Example 4, the opacity and the decreased strength resulted from the relatively high content of partial ester of about 10 percent by weight in the end product obtained copolymer.

Examples 6 to 8

Three mixtures of vinyl and vinylidene chlorides in the ratio used in Example 1, containing 0.4 percent by weight of o-chlorobenzoyl peroxide and 2 percent by weight of glycerol monocaprate, were ^{shaken for 45 hours at 50 °} in a closed tube with 2 volumes of an aqueous medium containing 10 , 20 and 30 percent by weight of methanol, respectively. After this time, the polymerization was practically complete, and the copolymers were, as described in Example 1, worked up and pressed. All of them had good color and fluidity and gave monofilaments of good mechanical strength, the effect of increasing the amount of methanol in the aqueous phase being to slightly increase the fineness and uniformity of the interpolymer particles. These three examples were repeated using ethanol and only 1% glycerol monocaprate in place of methanol, whereby white granular powders of similar properties were obtained.

Examples 9 to 12

Four mixtures of vinyl and vinylidene chlorides in the ratio used in Example 1, containing 0.2 percent by weight of o-chlorobenzoyl peroxide and ι percent by weight of glycerol ^{monocaprate, were shaken for 66 hours at 50 0} with 2 parts by volume of an aqueous medium containing 0.1 percent by weight of sodium bicarbonate and 10 percent by weight ethanol or 10 percent by weight n-butanol, 10 percent by weight tert. Contained butanol and 2 percent by weight lauryl alcohol. The pn values of the dispersions in the four examples were 3.3 and 3.7, 4.2 and 4.0, respectively.

After 66 hours the polymerization was practically complete and the polymers were filtered, dried, plasticized and pressed without washing. The copolymer showed in all cases good fluidity and the filaments were clear, showing no signs of deterioration and had good mechanical properties.

The last example was then repeated, with ο, ι percent by weight, calculated on the aqueous phase Polyvinyl alcohol was used as a protective colloid and the lauryl alcohol was omitted. In In this case the dispersion obtained was at least as good, but the copolymer decomposed partially during the pressing process, and a single thread in a dark color was obtained.

B e i s ρ i e 1 13

A mixture of vinyl and vinylidene chlorides in the used in Example 1 ratio containing I weight percent glycerol and 0.4 weight percent of benzoyl peroxide, was shaken for 45 hours at 50 ⁰ in a glass tube with 2 volumes of water. After this time, the polymerization was practically complete and the copolymer was deposited as a fine-grain powder containing a few small beads. After drying, plasticizing and pressing, single threads were in good Farlx? and obtained with good strength.

This example was repeated using an aqueous medium instead of water that was 10, 20 and 30 percent by weight

Ethanol contained and
were holding.

giving the same results

Example 14

A mixture of vinyl and vinylidene chloride in a ratio of 15:85, containing 0.2 percent by weight of caprylyl peroxide and 1 percent by weight of glycerol monocaprate, was shaken in a sealed tube at 50 ° and 2 parts by volume of an aqueous medium containing 0.20 percent by weight of sodium carbonate ; the dispersion had a _pH value of 6.9. After 45 hours, the polymerization was 80% complete, and the copolymer was precipitated by filtration as a powder containing a few small pearls. Worked up and pressed as in Example 1, single threads of good color and good mechanical strength were obtained.

i s ρ i e 1 15

Vinylidene chloride containing 1 percent by weight of glycerin monocaprate and 0.2 weight percent Caprylylperoxyd was contained at 50 ⁰ with 2 volumes of an aqueous medium containing 0.20 percent by weight sodium bicarbonate and 10 weight percent n-butanol, shaken; the final p ^ value of the nis]> ersion was 7.4. After 40 hours the polymerization was 80% complete and the polymer was recovered as a granular powder by filtration. After drying, it had a good heat resistance at 175 ^0th

Examples 16-18

3 parts of a mixture of vinyl and vinylidene chloride in a weight ratio of 15: 85 contained the 0.2 weight percent o-Chlorbenzoylperoxyd and 1.3 or 2.8 and 1.1 weight percent Glycerinmonoheptoat, 45 hours at 50 ⁰ were mixed with 2 parts by volume of Water or 2 parts by volume of water and 2 parts by volume of aqueous ioVoigen ethanol. The pH values of the dispersions were 5.2 and 3.9 and J, J, and the polymerization was practically complete after 45 hours. After filtering, drying and mixing, the copolymers were pressed; the individual threads were clear, of good color and good mechanical strength.

Examples 19 to 21

3 parts of a mixture of vinyl and vinylidene chloride in a weight ratio of 15: 85 containing 0.2 weight percent o-Chlorbenzoylperoxyd and 4 weight percent glycerol, and 1 weight percent Glycerinmonoheptoat or glycerol monocaprate and glycerol monolaurate contained, 45 hours at 50 ⁰ were mixed with 2 parts by volume of water containing 0.2 weight percent sodium bicarbonate, shaken. After this time the degree of polymerization was 90 or 95 and 90%; the copolymers were separated off by filtration and dried

and plasticized. When pressed, clear filaments became of good color and good mechanical ones Maintain strength.

Examples 22 to 24

3 parts of a mixture of vinyl and vinylidene chloride! in a weight ratio of 15 185, which contained 0.2 percent by weight o-chlorobenzoyl peroxide and ι percent by weight glycerol monocaprate and 2 or 5 and 10 percent by weight monoacetin, were each ^{shaken in a sealed tube with 2 parts by volume of water at 50 0} 45 hours. After this time, at which the degree of polymerization was 80%, the copolymers were filtered, dried, plasticized and pressed; the monofilaments had good color and strength and good strength and moderate strength, respectively. ^l

Example 25

A mixture of vinyl and vinylidene chloride in a weight ratio of 15:85, which contained 0.2 percent by weight of o-chlorobenzoyl peroxide and 1 percent by weight of glycerol monocaprate, was placed in a sealed tube with 2 parts by volume of an aqueous medium that contained sGewicht% n-butanol and 5 weight percent acetic acid , shaken; the pH of the dispersion was 2.9. After shaking at 50 ⁰ 45stündigem the degree of polymerization 85 ° / o was; the copolymer was separated off by filtration, dried and mixed. When pressed, a clear thread of good color and strength was obtained.

Examples 26-28

3 parts of a mixture of vinyl and vinylidene chloride in a weight ratio of 15:85, the 0.2 percent by weight o-chlorobenzoyl peroxide and 0.5 percent by weight glycerol monocaprate and 0.5 percent by weight glycerol monolaurate or 1 percent by weight glycerol monocaprate and 1 percent by weight glycerol monolaurate and 0.5 percent by weight Glycerol monocaprate and 0.5 percent by weight glycerol monoheptoate were each shaken in a closed tube with 2 parts by volume of water containing 0.2 percent by weight sodium bicarbonate; the pn-value of the dispersion was 4.5 and 7.8 and 7. After 42stündigem shaking at 50 ⁰ the degree of polymerization was 90 or 85 and 90%; the copolymers were obtained by filtration as small beads or granular powder. The individual threads pressed from the dried and plasticized copolymers had good color and good mechanical strength, and the copolymers had good flowability during pressing.

Examples 29 and 30

2 parts of a mixture of vinyl and vinylidene chloride in a weight ratio of 15:85, the 0.2 percent by weight of o-chlorobenzoyl peroxide and

ι and 0.5 percent by weight sorbitan monostearate contained, 45 hours at 50 ⁰ were in a sealed tube with 2 parts by volume of water containing 0.3 weight percent sodium bicarbonate, shaken. After this time, at which the degree of polymerization was 95 ° / °, the copolymers were obtained as a fine-grain powder, which was dried and plasticized. During pressing, clear single threads of good color and good mechanical strength were obtained.

Examples 31 to 33

As in Example 30, three interpolymerizations were carried out, but it was used for the Example 31 a mixture of 0.5 percent by weight glycerol monolaurate, 0.5 percent by weight glycerol monoheptoate and 0.5 'percent by weight glycerol monocaprate, for example 32 a mixture of

ao 0.5 percent by weight glycerol monobutyrate and 0.5 percent by weight glycerol monoheptoate and for Example 33 1 percent by weight of glycerol monobutyrate alone instead of that used in Example 30 0.5 weight percent sorbitan monostearate used.

In any case, the copolymer in the form of small beads in 95 ° / »ig ^e r yield was won th-.nen, and the individual filaments obtained were clear and had good color and good mechanical strength.

B e i s ρ i e 1 34

Contained a mixture of vinyl and vinylidene chloride in a weight ratio of 15:85, the 1 weight percent and 0.2 weight percent Pentaerythritdicaprat Q-benzoyl peroxide, was shaken in a sealed tube at 50 ⁰ 40 hours with 2 parts by volume of water. After this time the degree of polymerization was 95 ° / °> and the polymer obtained gave, after drying, mixing and pressing, clear individual threads of good color and good mechanical strength.

This example was repeated using the dilaurate instead of the dicaprate; very similar results were obtained.

Example 35

Example 34 was repeated, a sorbitan monostearate polyoxyalkylene derivative being used in place of the pentaerythritol dicaprate. The resulting dispersion had a _pH value of 2.8, and the yield after 40 hours was 90 ⁰ / o of a copolymer in the form of granules. The individual threads pressed from the polymer were clear, had good color and good strength.

For comparison with this example, the interpolymerization was repeated, where, calculated on the aqueous phase, 0.1 percent by weight isopropylnaphthalenesulfonic acid Sodium was used instead of the ι percent by weight of the partial ester calculated on the monomeric material. The copolymer was obtained in the same yield as a mixture of powder and small beads and was carefully washed with hot water before drying. Despite this washing however, the trace of the remaining dispersant caused decomposition of the plasticizer Polymers when pressed, and the monofilament produced was poor in color.

Example 36

Vinyl chloride was emulsified in the liquid phase in a sealed tube with 2 parts by volume of water and 1 percent by weight of the sorbitan monolaurate polyoxyalkylene derivative and 2 percent by weight sorbitan monolaurate and 1 percent by weight benzoyl peroxide; the percentages by weight are calculated on the vinyl chloride. The polymerization was carried out without agitation for 48 hours at 40 ^0, and polyvinyl chloride was obtained as a partially coagulated latex at 85 ° / cent yield. The polymer obtained was good thermally stable at 175 ^0th

This example was repeated, with 0.5 weight percent crotonyl peroxide in one case and 0.5 percent by weight of o-chlorobenzoyl peroxide in the other case instead of the 1 percent by weight Benzoyl peroxide was used; the same results were obtained.

Example 37

A mixture of vinyl and vinylidene chloride in a weight ratio of 15:85. This is 0.4 percent by weight Benzoyl peroxide and 1 percent by weight glycerol monocaprate was 41 hours with 2 parts by volume of an aqueous phase containing 0.2 percent by weight sodium bicarbonate and 4 percent by weight a solution of. Contained sodium hypochlorite with 10 percent by weight active chlorine, shaken. After this time, the polymerization was 90% complete, and so was the mixed polymer was obtained as a granular powder. By working up and pressing, as in Example 1, were obtained transparent filaments of good color and firmness.

Example 38

Vinyl chloride was charged in the liquid phase in 2 parts by volume of water containing 0.8 weight percent based on the monomer, sorbitan monostearate, and 0.2 percent by weight contained Triäthanolaminstearat dispersed, and the polymerization was calculated at 50 ⁰ in the presence of 0.2 weight percent based on the monomer o -Chlorobenzoyl peroxide carried out. The polymer was obtained as a fine powder and had good flowability and heat resistance when a plastinated product was pressed.

Examples 39 u η d 40

Two mixtures, one of which is 85 percent by weight vinylidene chloride, 10 percent by weight

Vinyl chloride and 5 weight percent vinyl methoxybutyrate and the other 85 weight percent vinylidene chloride and 15 weight percent vinyl methoxyhutyrate were polymerized as described in Example 38, but using of 0.5 percent by weight of sorbitan monostearate and 0.5 percent by weight of glycerol monocaprate as dispersants. After the products were plasticized, there was no decomposition during pressing observed, although the temperature required for the second sample was very high. Similar results were obtained when, calculated on the monomeric mixture, 1 percent by weight Pentaerythritol monolaurate was used as a dispersant.

Examples 41 and 42

Using a phase ratio of ι monomer to 2.5 water and 0.2 percent by weight o-Chlorobenzoyl peroxide as a catalyst, two polymerizations were carried out, their Details are given in the table below.

example
No. Monomer weight percent temperature duration
in hours Dispersants
Weight percent Polymeri
degree of sation 4i Butyl itaconate 15%
Vinyl chloride 15%
Vinylidene chloride 70% 50 ° 42 Sorbitan monostearate 1%> 90% 42 Cyclohexyl itaconate 50/0
Vinylidene chloride 5% 6o ° 70 Sorbitan monopalmitate 0.5%
with glycerine monocaprate 0.5% 97 ° / o

The copolymers were obtained as fine, granular dispersions. After plasticization with 10 weight percent Dimethylbenzyläther the copolymer of Example 41 was slightly pressed at 160 to 165 ⁰ and that of Example 42 occurred at 170 ⁰ without any signs of decomposition.

Example 43

A mixture of 10 parts by weight of ethyl acrylate, 12 parts vinyl chloride and 78 parts of vinylidene chloride was dispersed in 2.5 parts by volume of water with the aid of ι Pentaerythritmonolaurat part and the polymerization carried out by means of potassium persulfate at 50 ⁰ 0.3 parts. After 42 hours 1> is the degree of polymerization 53 ° / ° ^"an d the üimethylbenzyläther with 10 percent by weight of plasticized and at 165 to 170 ⁰ pressed polymer flowed easily etrug and had no signs of decomposition recognize.

in all of these examples the polymerization was carried out in a closed tube and the any shaking applied caused by a final overturning; however, it can also be any other type of container suitable for the polymerisation of the monomers in aqueous dispersion is used will. For example, the dispersion can be placed in a heating bath through a pipe system Conditions of turbulent flow or steady flow are sent through, whichever is unstable or stable dispersions can be used, or the polymerization can also be carried out under pressure or carried out under reflux in order to avoid loss of monomer.

Claims (5)

PATENT CLAIMS: - 1. Process for the polymerization of vinyl chloride, vinylidene chloride or mixtures thereof with or without the use of small amounts of other compounds which can be polymerized therewith in aqueous dispersion, characterized in that a Partial ester from a polyhydric alcohol with a maximum of 10 hydroxyl groups in the molecule and a fatty acid having at least 4 carbon atoms in the molecule in amounts up to about 5 percent by weight of the monomeric substances is used. 2. The method according to claim 1, characterized in that that a partial ester of a hexitane or hexide is used. 3. The method according to claim 1, characterized in that pentaerythritol laurate or stearate is used as the partial ester. 4. The method according to claim 1 to 3, characterized in that a condensed with ethylene oxide Partial ester is used. 5. The method according to claim 1 to 4, characterized in that the polymer produced separated from the aqueous phase and dried without any intermediate washing. 1 3420 3.