DE1520688C3 - Process for the preparation of copolymers containing hydroxyl groups - Google Patents

Description

R —C-O-CHo-CH CH,

in which R is an aliphatic or aromatic substituent which has one or more May contain ethylenically unsaturated bonds, is used, optionally the glycidyl ester is already added during the preparation of the copolymers.

2. The method according to claim I, characterized in that that the glycidyl ester is glycidyl benzoate or sunflower fatty acid glycidyl ester begins.

3. Use of the products obtained according to claims 1 and 2 for the production of air-drying or oven-hardening lacquers.

Many manufacturing processes for copolymers containing hydroxyl groups are known.

In British Patent 773 206, the implementation of copolymers from one or several ^ // - unsaturated carboxylic acids and with one or more vinyl monomers with F.poxygruppcn containing triazines without esterification catalysts with heating to 160 "C already described.

From US Pat. No. 2,607,761 a process is known in which a styrene-maleic anhydride copolymer in aqueous alkaline solution with alkylene oxides or Aiylalkylenoxden or Epichlorohydrin is implemented. An aqueous medium with a strong alkali as a catalyst is required for this reaction necessary.

US Pat. No. 3,023,178 describes the conversion of epoxidized esters of unsaturated ones Vegetable oleic acids with compounds containing carboxyl groups to form insoluble, infusible, flexible and non-stick films by applying and applying a physical mixture of the starting components is burned in.

The invention, however, is a process for the production of copolymers which are described in organic solvents are soluble and have a defined composition before coatings made from it and baked in.

The object of the invention is to produce vinyl copolymers containing hydroxyl groups of hydroxyl groups in situ during and after the copolymerization reaction and without the need the use of any catalyst, apart from one of the conventional polymerization catalysts, to provide. This has practical implications because of the presence of Catalysts in paints and other coatings made from copolymeric products can have a detrimental effect.

ίο The invention is a method for Production of copolymers containing hydroxyl groups which are soluble in organic solvents Implementation of copolymers made by polymerizing \, // - unsaturated carboxylic acids with a or other vinyl compounds have been produced in solvents at elevated temperature, with compounds containing epoxy groups without esterification catalyst with heating up to 160 ° C, thereby characterized in that the epoxy group-containing compound is a glycidyl ester of the general formula

R - C - O - CH ₂ - CH CH ₂
O °

in which R denotes an aliphatic or aromatic substituent which is one or more ethylenically May contain unsaturated bonds, is used, where appropriate the glycidyl ester already is added during the preparation of the copolymers.

In the process of the invention, there is thus a non-aqueous solvent system, and it is also worked in the absence of an esterifiable catalyst.

The reaction is brought about by increasing the temperature while removing the solvent - only if necessary - by distillation, as shown in the following examples. The reaction is completely carried out when the acidity has reached a minimum, and proceeds as follows:

COOH \ CH, CH - CH, - O - C - R ->

C - O - CII, - CH - CH, - O - C - R

OH O

O CII ₂ OH

■ C - O - CH - CH, - O - C - R

These conversions can also be carried out as a one-step reaction. In examples 6 and 13 this one-step conversion is clarified. Examples of \, /? - unsaturated carboxylic acids are Acrylic acid, methacrylic acid, maleic acid and fumaric acid and their monocsters.

Examples of suitable further vinyl compounds

are styrene, \ -methyl-styrene, vinyltoliol, vinyl acetate, Esters of acrylic and methacrylic acid and nitrogen-containing derivatives of the latter such as acrylamide.

A special embodiment of the invention is characterized in that the glycidyl ester is glycidyl benzoate or sunflower fatty acid glycidyl ester begins.

A special use of the process products is the production of oven-hardening paints, whereby the Copolymers according to the invention are mixed with etherified amino and / or epoxy resins.

Another special use of the process products is the manufacture of paints according to the Two-component system, where the copolymer with an isocyanate prepolymer or a polyisocyanate.

Another special use of the process products is the manufacture of air-drying products Lacquers, where a copolymer prepared according to the invention is mixed with a dry catalyst will.

Another special use of the process products is the manufacture of oven-hardening products Lacquers, the copolymer being mixed with an amino resin.

In the examples below, the glycidyl esters of alkylalkane monocarboxylic acids and / or dialkylalkane monocarboxylic acids are used (referred to as glycidyl ester E). These acids mainly represent a mixture of C ₉ , Ci ₀ and C ₁₁ monocarboxylic acids, which have been prepared from a mixture of C _s , C ₉ and C ₁₀ olefins with carbon oxide and water. The acids are completely saturated and very heavily substituted on the v-carbon atom. There are no acids with two hydrogen atoms on the λ carbon atom, and only 6 to 7% of these acids contain a hydrogen atom on the carbon atom. In addition, there is cyclical material (Deutsche Farben-Zeitschrift, issue 10, 16th year, p. 435).

B is ρ ie 1 1
The following mixture consisting of

Commercial xylene 231 g

n-butanol 77 g

Lauryl mercaptan 2 g

is heated to 120 " ¹ C with stirring. Then the following ingredients are added one after the other, distributed over a period of 2 hours, at a temperature of 120 ° C:

Styrene HOg

Butyl acrylate 40 g

.Methacrylic acid 50 g

Di-tert-butyl peroxide 6 g

The mixture is then kept at a temperature of 120 ° C. for a further 2 hours. The non-essential portion of this solution should at this point be 31 to 34 ° C. ° C brought to the theoretical value of 39 ° / "for a period of 2 hours.

108 g of glycidyl ester E are added and the temperature is gradually brought to 160 ° C., as a result of which the solvent is distilled off and can collect in the receiver. The temperature is kept at 160 ^° C. until the acid number falls to a minimum of 21. The filling is then cooled slightly and the solvent which has been distilled off is added again (if it should prove necessary, other solvents can be added at this point). The final solution has after it is adjusted by xylene ίο to a content of 50 ° / ₀ non-volatile matter, a viscosity according to Gardner - Holdt of V-W and an acid value of. 13

Example 2
The following mixture consisting of

Commercial xylene 462 g

n-butanol 154 g

Lauryl mercaptan 4 g

is heated to 120 ° C. with stirring. The following mixture is then added in portions, distributed over a period of 2 hours, the temperature of 120 ^° C. being maintained:

Styrene 200 g

Butyl acrylate 100 g

Methacrylic acid 100 g

Di-tert-butyl peroxide 12 g

The mixture is then kept at 120 ° C. for a further 2 hours. The content of the solution of non-volatile should now / amount to 33-34 °, and ₀ is increased by the addition of 4 g of di-tert-butyl peroxide and heating for 2 hours at 120 ° C on the theoretical value of 39%.

After adding 216 g of glycidyl ester E, the temperature is gradually increased to 160 ° C. until the acid number drops to a minimum value of about 24 for the present example. The filling is then cooled slightly and the solvent which has been distilled off is added back to the contents. This final solution has 50 ° / ₀ nichtfUichtige components, the viscosity according to Gardner - Holdt is V to W and the acid number fourteenth

It is surprising that in the process according to the invention, the reaction of the glycidyl esters is carried out at temperatures between. 100 to 160 ⁰ C is possible in the absence of a catalyst and that the reaction can take place in situ during or after the copolymerization.

To make this clear, the following comparative tests are carried out.

Comparative experiment a)

Example 2 was repeated with the modification that 72 g of phenyl glycidyl ether were used in place of 125 g of glycidyl ester E on an exactly equivalent epoxy basis. When the temperature of this batch was kept at 160.degree. C., the acid number only dropped to the value 55, instead of the acid number 11, which was obtained in the parallel experiment according to Example 2.
65

Comparative experiment b)

In a further comparison worked according to Example 2, however, the equivalent amount (55 g)

Allyl glycidyl ether is used in place of the 125 g glycidyl ester E. While keeping the temperature at 160 "C this approach, the acid number fell to the value 75 instead of falling to the acid number 11, as in the Comparative experiment according to the invention happened.

Example 3 The following mixture consisting of

Commercial xylene 257 g

n-butanol 86 g

Lauryl mercaptan 2 g

is heated with stirring to 12O ⁰ C. The five mixtures [a) to e)] listed below are then added in portions within half an hour at 120 ° C:

a) styrene 20 g

Ethyl acrylate 10 g

Acrylic acid 1.5 g

Di-tert-butyl peroxide 1.2 g

then

b) styrene 20 g

Ethyl acrylate 10 g

Acrylic acid 3 g

Di-tert-butyl peroxide 1.2 g

after that

c) styrene 20 g

Ethyl acrylate 10 g

Acrylic acid 6 g

Di-tert-butyl peroxide 1.2 g

further

d) styrene 20 g

Ethyl acrylate 10 g

Acrylic acid 12g

Di-tert-butyl peroxide 1.2 g

further

e) styrene 20 g

Ethyl acrylate 10 g

Acrylic acid 27.5 g

Di-tert-butyl peroxide 1.2 g

The mixture is then kept at a temperature of 120 ° C. for a further 2 hours. A further 2 g of di-tert-butyl peroxide are added and heating is continued at 120 ^° C. for a further 2 hours. Further 1 g of di-tert-butyl peroxide are added and the heating for a period of a further 2 hours continued whereby the theoretical non-volatile content of 36 ° to 37 ° / ₀ constituents is obtained. 163 g of glycidyl ester E are then added and the temperature is gradually increased to 160 ^° C., as a result of which the solvent is distilled off and can collect in the receiver. The temperature of 160 "C as long retained, has dropped to a minimum of about 11 until the acid number. The filling is then cooled slightly and zurückgcleitet the abdcstillicrte solvent to the contents. The final solution has non-volatiles by now 50 ° / ₀ , the Gardner-Holdt viscosity is Q to R and the acid number is 7.

Example 4
The following mixture consisting of

Commercial xylene 207 g

n-butanol 69 g

Lauryl mercaptan 2 g

is heated to 120 "C with stirring and the following Mixture added one after the other within 2 hours - at 120 ° C:

Styrene 100 g

Butyl acrylic 50 g

Methacrylic acid 50 g

Di-tert-butyl peroxide 6 g

The mixture is then kept at a temperature of 120 ° C. for a further 2 hours. The non-volatile constituent of the solution should now be 34 to 36% and is brought to the theoretical value of 42% by adding 2 g of di-tert-butyl peroxide and heating at 120 ° for two more hours. After adding 76 g of glycidyl benzoate, the temperature is gradually increased to 160 ° C. , as a result of which the solvent is distilled off and can collect in the receiver. This process continues until the acid number drops to the minimum of about 28.

The mass is then cooled and diluted with a 3:-xylene-butanol mixture 1 lowered to a content of nonvolatile components of 50 ° / _0th The final solution thus obtained has a Gardner-Holdt viscosity of Z _{: 1} and an acid number of 16.5.

Example 5
The following mixture consisting of

n-butanol 25 g

Commercial xylene 50 g

Methyl isoamyl octone 25 g

Methacrylamide 5 g

Styrene 30 g

Butyl methacrylate 20 g

Ethyl acrylate 30 g

Methacrylic acid 15 g

Di-cumylpcroxide Ig

is placed in a flask equipped with a reflux condenser and stirrer, gradually heated to 120 "C. and held at this temperature for 2 hours. After adding another 1 g of di-cumylpcroxide the temperature is kept at the same level for a further 2 hours, around the theoretical get non-volatile component \ on 50%. 32 g Glycidylstcr E are added and the temperature increased to 160 "C, whereby the Solvent can be distilled off into the receiver. The temperature is kept at 160 C until the acid number has reached a minimum of 8.5. The material is then cooled and the solvent distilled returned in the material. The final solution obtained in this way gives after adjustment with a 2: 1: 1 xylene: n-butanol: methylisoamyl octone mixture on non-volatile components of

7 8

50 _^0/0 a viscosity of Z ₁ to Z ₂ and the acid number viscosity according to Gardner - Holdt of 7, and is 4.9. the acid number is 7.6.

Example 16 _n · · ι ο

Examples

The following mixture, consisting of 5 _{the fo} , _{gende Ccmisc} ^ _{consisting of}

Ethyl glycol acetate 84 g Commercial xylene 257 g

n-butyl glycol acetate 28 g n-butanol 86 g

Methyl isoamyl ketone 28g Lauryl mercaptan 2g

IO

and 40 g of glycidyl ester E are heated to 120 ° C. with stirring. Then become

130 ° C heated and the following mixture por- the five mixtures listed below [a) to

tionwise over a period of 2 hours - in e)] in portions within a period of each

Maintain the temperature of 130 "C - add half an hour - while maintaining the temperature

given: 15 temperature of 120 ° C - added:

Ethyl acrylate 52 g a) styrene 20 g

Methyl methacrylate 30 g ethyl acrylate 10 g

Methacrylic acid 18 g acrylic acid 1.5 g

Di-cumyl peroxide 2 g _2O di-tert-butyl peroxide 1.2 g

then

The temperature then increases for a further 2 hours

kept at 130 ^° C. The non-volatile components b) styrene ~ 20 g

10g by adding 1 g of di-cumyl peroxide ethyl acrylate

and heating for 2 hours at 130 ° C. to the theoretical acrylic acid 3 g

see value of 50 ° / ₀ brought. The temperature becomes di-tert-butyl peroxide 1.2 g

then increased to 150 ^° C. until the acid number is constant

is at least 11. The solution obtained has a further

Viscosity from H to I and an acid number of 10.4.

The products of these examples can include 30 c) styrene 20 g

for the production of lacquers use, ethyl acrylate 10g

in connection with etherified amino resins acrylic acid 6 g

and / or epoxy resins, at curing temperatures di-tert-butyl peroxide 1.2 g

between 120 to 180 ° C.

". . , “35 of the further

B e1sp1e 1 7

The following mixture consisting of d) styrene 20 g

Ethyl acrylate 10 g

Commercially available xylene 244 g acrylic acid 12 g

n-butanol 81g ₄₀ di-tert-butyl peroxide 1.2 g

Lauryl mercaptan 2 g

then

is heated to 120 ° C. with stirring, and the mixture listed below is added in portions, e) styrene 20 g

over a period of 2 hours, maintaining 45 ethyl acrylate 10 g

tion of the temperature of 120 ^° C., added: acrylic acid 27.5 g

Di-tert-butyl peroxide 1.2 g

Styrene 100 g

Butyl acrylate 50 g Thereafter, the mixture is further to 120 ° C for the

Methacrylic acid 50 g 50 held for 2 hours. After another

Di-tert-butyl peroxide 6 g of addition of 2 g of di-tert-butyl peroxide becomes the Er

continued heating at 120 ° C for an additional 2 hours.

The mixture is then kept at 120 ° C. for a further 2 hours. The heated nichtfiüchtige added and further 2 hours at 120 ⁰ C, part of this solution should now be 32 to 33% 55 be thereby the theoretical non volatile content and is prepared by adding 2 g of di-tert-components 36-37 ° / " is achieved. Butyl peroxide and additional 4 hours of heating. After adding 163 g of glycidyl ester E, becomes

at 120 ° C to the theoretical value of 38% ge the temperature gradually increased to 160 ° C, whereby brings. distill off the solvent and place in the template

Then 125 g of glycidyl ester E are added 60 can be collected. The temperature of 160 ° C and the temperature is increased to 160 ° C, thereby maintaining that until the acid number is at a minimum Distilling off the solvent in the template has reached 11. The product then becomes light becomes possible. The temperature is cooled to 160 ° C. and with a solvent mixture of hold until the acid number is at least 11. The 2: 1 xylene to ethyl glycol acetate on a non-volatile material is cooled down and reduced by 50% by adding 65 genes. That way Xylene on a 50%, non-volatile component obtained solution, which is practically butanol-free, has set. The solution obtained in this way, which has a Gardner-Holdt viscosity of is now almost free of butanol, now has a U to V and an acid number of 7.3.

9 10

Example 9 Example 11

The following mixture consisting of The following mixture consisting of

Commercially available xylene 207 g ₅ Commercially available xylene 600 g

n-butanol 69 g n-butanol 300 g

Lauryl mercaptan 2 g Lauryl mercaptan 6 g

is heated to 120 ^° C. with stirring and the subsequent and the following reaction mixture, consisting of:

standing listed mixture in portions over io

a period of 2 hours - while maintaining styrene 300 g

the temperature of 120 ° C. - added: butyl acrylate 120 g

Methacrylic acid 180 g

Styrene 100 g di-tert-biityl peroxide 80 g

Butyl acrylate 50 g 15

Methacrylic acid 50 g are treated according to Example 10 to give a

Di-tert-butyl peroxide 6 g content of theoretical non-essential components

of 40 ° / ₀ .

The mixture is then added for a further 2 hours to 504 g of glycidyl ester E and a temperature of 120 ° C. is maintained. The temperature content increased gradually to 160 ¹¹ C, the non-volatile constituents of this solution should now be distilled off and the solvent collected in more than 34 to 36 ° / ₀ . To enable by adding the template again. The temperature of the paste of 2 g of di-tert-butyl peroxide and 2stündiges 160 ° C is maintained until the acid number minimal heating at 12O ^'J C, the content of 4,0 is nichtllüchtigen is. The material is then slightly cooled ₀ abge constituents on the theoretical value of 42 ° / 25 ° and reacted with 99.5 / "pure ethyl acetate sodium on. a content of 50 ° / _o by weight nonvolatile matter 76 g-glycidyl be lowered share then added. The solution obtained in this way and the temperature gradually increased to 160 ^° C. has a viscosity according to Gardner-Holdt, which means that the solvent is distilled off from R to S and has an acid number of 2.1. can ren. This process will continue until 30
until the acid number drops to the minimum of about 28. The product is cooled slightly and an example 1_ content of 50 ° / ₀ nonvolatile component ance with _the following mixture consisting of 99.5 established by addition ^I! / _O igen pure ethyl acetate.

The final solution obtained in this way, which is practically butanol-free, 35 commercially available xylene 1000 g

has a Gardner-Holdt viscosity of X and n-butanol 500 g

an acid number of 16.3. Lauryl mercaptan 10 g

and the following reaction mixture consisting of: B eis ρ ie 1 10 ^ ₀

". . . . ". ,,. ,. Styrene 500 g

The following mixture consisting of butyl acrylate 100 g

Commercially available xylene 480 g methacrylic acid 400 g

n-butanol 120 g of D.-tert.-butyl peroxy. d 30 g

Lauryl mercaptan 6 g ⁴⁵ "

are treated exactly as in Example 11 to the

and the following reaction mixture, consisting of: theoretical content of 40% non-volatile

components.

gjy _ro [300 ΐί 1120 g of glycidyl ester E are added and

Butvl'ic'rvlat 180 ^{r 5} ° ^ ^Ie temperature gradually increased to 160 "C to

Methacrylic acid 120 κ ⁽ ' ^as distilling off the solvent and collecting

^Allowing di-tert butyl peroxide 18k ^{me 'n' n} ^ ^he original. The temperature

of 160 ° C is maintained until the acid number is minimal 6.5 is. The material is cooled slightly

are treated according to Example 7 to the 55 and 99.5% pure ethyl acetate on one

theoretical non-volatile content 50% non-volatile content

of 50%. lowered. The solution obtained has a viscosity

33 g of glycidyl ester E are then added from Q to R and an acid number of 3.6. and the temperature gradually increased to 160 "C, whereby the solvent can distill off and collect in the 60 B bis ρ ic I 13 receiver. The temperature -vird
160'C maintained until the average acid value in ^{the fol} S ^mixture consisting of

this case drops to about 8. Ethyl glycol acetate 84 g

The material is cooled slightly and 28 g with 99.5% n-butyl glycol acetate

pure ethyl acetate to a content of 50% non-55 methyl isoamyl ketone 28 g

volatile components set. The on this

The solution obtained in this way has a viscosity of J-f and 40 g of glycidyl conductor E is increased with stirring

and an average acid number of 5.2. 130 "C heated and the following mixture por-

tion wise within 2 hours - while maintaining the temperature of 130 ° C - added:

Methyl methacrylate 30 g

Ethyl acrylate 52 g

Methacrylic acid 18 g

Di-cumyl peroxide 2 g

The mixture is then held at 130 ° C. for a further 2 hours. By adding 1 dicumyl peroxide and heating at 130 g ⁰ C for a further 2 hours, the content of nonvolatile components on the theoretical value of 50 ° / ₀ is increased. The temperature is increased to 150 ^° C. and this temperature is maintained until the acid number is a constant minimum of 11. The solution obtained in this way has a viscosity from H to I and an average acid number of 10.4.

The products obtained according to Examples 7 to 13, which are essentially free of hydroxyl groups containing solvents can be used in conjunction with isocyanates as a basis for two-component hardener systems be used, which cure quickly at room temperature on the one hand and as oven-curing lacquers to the desired ones on the other Lead coatings.

Example 14
The following mixture consisting of

Commercial xylene 112 g

n-butanol 38 g

Lauryl mercaptan Ig

is heated to 120 ^° C. with stirring, with the introduction of inert gas, and then the following mixture is added in portions over the course of 2 hours - while maintaining the temperature of 120 ^° C.

Butyl acrylate 25 g

Vinyl toluene 50 g

Methacrylic acid 25 g

Di-tert-butyl peroxide 3 g

The mixture is then kept at 120 ° C. for a further 2 hours. The addition of 1 g of di-tert-butyl peroxide while maintaining the temperature of 120 ^° C. for a further 2 hours gives the theoretical non-volatile content of 40%.

107 g glycidyl ester of sunflower fatty acids are added and the temperature gradually increases 16O "C increased, whereby the solvent distilled off and can collect in the template. The temperature is held at 160 "C until an acid number from a minimum of about 6 is reached. The product is cooled and divided into two parts. The first lot is adjusted to a non-volatile content of 50% with white spirit. This solution has a Gardner-Holdt viscosity from R to S, an acid number of 2.7 and is arbitrary Can be thinned with white spirit.

The other half is mixed with commercially available xylene to a non-volatile content of 50% set. This solution has a viscosity from I to J, an acid number of 2.8 and is arbitrary Can be thinned with commercially available xylene.

B e i s ρ i e 1 15

The following mixture consisting of

Commercial xylene 112 g

n-butanol 38 g

Lauryl mercaptan Ig

is heated with stirring to 12O ⁰ C - portionwise under supply of inert gas and the mixture set forth below in the course of 2 hours, - at the same temperature (12O ⁰ C) - added:

Ethyl acrylate 10 g

Vinyl toluene 60 g

Methacrylic acid 30 g

Di-tert-butyl peroxide 3 g

The product is kept at a temperature of 120 ^{° C. for a further 2 hours.} The addition of 1 g of di-tert-butyl peroxide and heating at 120 ^° C. for a further 2 hours increases the content of non-volatile constituents to the theoretical value of 40%.

89 g glycidyl ester of sunflower fatty acids are added and the temperature gradually increased increased to 160 ° C, whereby the solvent distilled off and can collect in the template.

The temperature of 160 ^° C. is maintained until the acid number has reached a minimum - in this case about 19.

The material is cooled and divided into two portions. The first portion is reduced with white spirit to a non-volatile content of 50%. The solution obtained has a viscosity of Z ₄ to Z ₅ , an acid number of 12.2 and can be continuously diluted with white spirit. The second part is reduced to a non-volatile content of 50% with commercially available xylene. The solution has a viscosity of Z ₁ , an acid number of 11.8 and is continuously soluble in commercially available xylene. These products can be used, among other things, for the production of air-hardening and oven-hardening lacquers, with the addition of suitable dry catalysts, or they can be used in conjunction with amino resins for oven-hardening lacquers.

Comparative experiments

In order to indicate the resistance of lacquer films to 1% sodium hydroxide solution at 20 ^° C., the following comparative tests were carried out and coatings of the same layer thickness were made on sheet steel from the solutions obtained. After a baking time of 30 minutes at 160 ^° C. and cooling, these caustic soda coatings were used and the properties of the film were assessed after a longer exposure time.

1. Example 1 of the invention was reworked and coatings on steel sheets were made from the solution obtained. The stoved films showed no attack after 50 hours' exposure to 1% strength sodium hydroxide solution at 20 ^° C. and still had a shiny appearance.

2. Example 2 of the invention was carried out according to

works and made coatings on steel sheets from the solution obtained. The films baked at 160 ^° C. also showed no attack after 50 hours' exposure to sodium hydroxide solution and remained bright.
3. Example 1 of the British patent

773 206 was reworked and, as described there, coatings were made on steel sheets, which are then also baked at 160 ° C. for 30 minutes. After 1 h exposure to l ° / ^r o'ge sodium hydroxide solution at 20 ⁰ C, the films were hazy appearance and had started white.

Claims (1)

Patent claims: I. Process for the preparation of soluble in organic solvents hydroxylgrirppenhaltigen Copolymers by reaction of copolymers obtained by polymerizing \, / i-imsaturated Carboxylic acids with one or more vinyl compounds at elevated temperature in Solvents have been prepared with epoxy-group-capable Compounds without an esterification catalyst with heating up to 160 "C, d u r c h characterized in that as containing epoxy groups Compound a glycidyl ester of the general formula