CS231147B1 - A method for producing polymeric materials with hydroxy ester bonds, in particular technical rubbers - Google Patents

Abstract

The purpose of the invention is to improve the technology for the production of polymer materials with hydroxyester bonds, in particular the production of technical rubber or flexible epoxy resins. The improvement consists in shortening the time required for sulfurization and reducing the crosslinking temperature. A catalytic combination consisting of polynuclear chromium complexes of organic monocarboxylic acids, aliphatic with a number of carbon atoms of 4 or aromatic, and of organic electron donor compounds, in particular tertiary amines, is added to the reaction mixture, formed by organic carboxylic compounds, in particular carboxyl-terminated telechelic polymers, and epoxides, in a weight ratio of both components of 5 to 95 to 60:40. This catalytic combination is added in an amount of 0.2 to 6 parts by weight per 100 parts of the reaction mixture. After homogenization, the material is crosslinked in the shape of the future product at a temperature of 100 to 160 °C. As an electron donor compound, a liquid that is well miscible with the chromium complex, for example quinoline, can be advantageously used.

Description

The purpose of the invention is to improve the technology for the production of polymer materials with hydroxyester bonds, in particular the production of technical rubber or flexible epoxy resins. The improvement consists in shortening the time required for sulfurization and reducing the crosslinking temperature. A catalytic combination consisting of polynuclear chromium complexes of organic monocarboxylic acids, aliphatic with a number of carbon atoms of 4 or aromatic, and of organic electron donor compounds, in particular tertiary amines, in a weight ratio of both components of 5 to 95 to 60:40 is added to the reaction mixture formed by organic carboxylic compounds, especially carboxyl-terminated telechelic polymers, and epoxides.

This catalytic combination is added in an amount of 0.2 to 6 parts by weight per 100 parts of the reaction mixture. After homogenization, the material is crosslinked in the shape of the future product at a temperature of 100 to 160 °C. A liquid that is well miscible with the chromium complex, for example quinoline, can be used as the electron donor compound.

.231 147

231,147

The invention provides a method for producing polymeric materials with hydroxyester bonds, in particular technical rubber or flexibilized epoxy resins, from organic carboxyl compounds, especially from telechelic polymers terminated with carboxyl functional groups.

The technique of processing carboxyl-terminated telechelic polymers, among which liquid rubbers occupy a dominant position, is currently not sufficiently developed. Given the specific physical and chemical properties of these materials, the processing processes known as Liquid Injection Moulding - LIM and Reaction Injection Moulding - RIM appear promising. The effective use of these investment-intensive technologies is hindered by the relatively long reaction times of carboxyl functional groups with crosslinking and modifying polyepoxide components.

Curing times are usually shortened by using basic catalysts, usually tertiary amines. In basic catalysis, acceleration of the reaction of carboxyl functional groups with epoxy functional groups - formation of substituted hydroxy esters - is often not sufficient, and undesirable side etherification reactions are also accelerated.

Simultaneous increase of catalytic effect and selectivity of reaction can be achieved by using catalysts based on trivalent molybdenum. Its organic complex (AMC-2) is commercially available, the catalytic activity of which can be blocked if necessary by electron donor reagents such as alcohols, amines, amides. Upon removal of these reagents - for example by evaporation in coating applications - the efficiency of the catalyst is restored.

- 1231 147

Other known catalysts are polynuclear chromium complexes of substituted salicylic acid. Their catalytic activity is relatively high, but their preparation according to AO 194 148 is relatively expensive and difficult and they exhibit a certain induction period during the reaction.

For the catalysis of carboxyl compounds with epoxy compounds, organic chromium complexes prepared by melting chromium salts with organic acids can also be used. However, the catalytic activity of these complexes is significantly reduced in polar media. When used in non-polar media, the disadvantage is that the complex in powder form has only limited solubility in this medium, which again reduces the catalytic activity.

The mentioned shortcomings of the known methods of catalyzing the reaction of carboxylic compounds with epoxides are eliminated by the method of producing polymer materials with hydroxyester bonds, in particular technical rubber or flexibilized epoxy resins according to the invention. The essence of the invention lies in the fact that a catalytic combination consisting of polynuclear chromium complexes of organic monocarboxylic acids, aliphatic with the number of C-atoms in the chain > 4 or aromatic, and of organic electron donor compounds, in particular tertiary amines, is added to a mixture of carboxylic compounds with epoxy compounds.

in a weight ratio of both components of 5:95 to 60:40 and dosed in an amount of 0.2026 parts by weight per 100 parts of the reaction mixture, after which the homogenized material is pressed into the shape of the product at a temperature of 100°C to 160°C.

In this way, technical rubber products can be obtained from a prepared mixture of a carboxyl-terminated telechelic polymer or oligomer and a polyepoxide compound within 0.5 to 10 minutes at a temperature of 150 °C. The catalysis used significantly prefers the formation of hydroxyester bonds over other, usually undesirable, reactions of epoxides.

As an agent capable of accelerating the reaction catalyzed by chromium complexes, for example, triethylenediamine can be used, preferably quinoline, which also serves as a solvent for the chromium catalyst, since the latter is poorly soluble in a non-polar medium.

231,147

The individual components can be mixed into the mixture gradually or simultaneously. The second of the above variants is more advantageous, especially if the components form a liquid mixture.

For the production of monolithic technical rubber, it is necessary to use in the catalyzing mixture such electron donor substances whose boiling point exceeds the selected crosslinking temperature. This condition does not apply to the production of porous materials. The method is also suitable for solution applications.

The advantages of the processing method according to the invention are illustrated by the following examples.

First, the efficiency of the catalytic combination according to the invention in catalyzing the reaction of epoxy resins with low molecular weight carboxylic acids was monitored in a solution configuration.

A solution containing 12.4 g of epoxy resin and 17.9 g of an equimolar dose of oleic acid in 68 ml of toluene was prepared. The solution was continuously stirred and heated to 76.5 °C with boiling tetrachloromethane vapor. The time loss of carboxyl and epoxy groups was determined by titration and the course was approximated by the second-order reaction kinetics equation. A chromium(III) complex of butyric acid was used for catalysis and triethylenediamine as an electron donor. The values obtained are given in the following table:

Table I

example no. amount of chromium component amount of electrondonor fg] rate constant ·, 1 1 0 5.03 2 1 1 23.7

Furthermore, the efficiency of the catalytic combination according to the invention in catalyzing epoxy resins with carboxyl-terminated telechelic polymers was monitored in detail.

acrylonitrile — number center molecular weight IL

231,147

A mixture was prepared consisting of 1 kg of a radical carboxyl-terminated liquid copolymer of butadiene with ·* 2934 g/mol carboxyl group content ^c 0oOH ^and 6.56·ÍO* ⁴ mol COOH/g, mean number functionality f _n * 1.925 - and 0.136 kg of aromatic epoxy resin - .« 481.5 g/mol} c _epoxy * 6.Ο44·1Ο^ mol epoxy/gj ? _n « 2.91. A quinoline solution of a polynuclear chromium complex of butyric acid was used for catalysis, in which quinoline is both a medium and an electron donor. This solution was designated as solution A. Comparative experiments were carried out with a solution of the same chromium complex in dioctyl phthalate, where dioctyl phthalate is only a medium to facilitate the dispersion of the chromium catalyst. The comparative solution was designated as solution B.

The catalyzed mixture was immediately sulfite-treated in the measuring chamber of the vulcameter. The experimentally determined vulcametric curve was mathematically modeled by a 1st order kinetic equation with a delay (induction period). The following characteristics were evaluated by correlation analysis:

- induced period t _Q &ύη]

- 1st order rate constant k^ [min J

- time of 95% change of modulus t^ [min]

Using these characteristics, the catalytic effects of individual mixtures were evaluated. The following was performed:

-comparison of the effects of the catalytic combination according to the invention with the most effective catalysis to date using the Or complex alone dissolved in an inactive solvent

- evaluation of the ratio of both components of the combination with respect to the desired effect

-determination of the appropriate range of reaction temperatures·

The determined characteristics, obtained depending on the individual parameters, are summarized in the following tables II Ctf IV.

231,147

Table II - comparison of the catalytic effect of solutions A and B at a vulcanization temperature of 14C °C, where A - catalytic combination according to the invention, B - solution of chromium catalyst in DOP and the proportion of chromium cat. in A and B is 33 wt. %

3rd verse No. content of solutions A-B fhmodZJ induction period t _Q fmin] rate constant time of 95% change in modulus t ₉₅ [min] A B A B And '·-·’ & 3 2 1.16 1.48 0.922 0.393 4.41 9.10 4 6 0.53 0.48 2,410 1,456 1.77 2.54 5 0.6 3.30 3.72 0.437 0.239 10.15 ,16,24 6 0.2 9.81 13.67 0.149 0.051 30.0 72.2

Table III - influence of the composition of the catalytic combination on the efficiency of catalysis at a total content of 2 wt.%/100 wt.% of the mixture and a vulcanization temperature of 140 °C

shoutout No. Chromium catalyst content [%] induction period t _Q [min] rate constant k^fmin] time of 95% change in modulus t ₉₅ fminj 7 60 1.36 0.579 6.53 8 5 5.77 0.1«3 24.2

Table IV - dependence of catalysis on temperature at total content wt.d./ΙΟΟ d. of the mixture and proportion of chromium component 33 wt.%

recital no. vulcanization temperature [°GJ induction period t _Q [min] rate constant© k^ ^nin~l] time of 95% change of modulus t _§5 (min]. 9 100 3.63 0.591 62.10 3 times/ 140 1.16 0.922 4.41 LO 160 0.76 1,231 3.21

x/ Note: The corresponding values from example 3 were used.

SUBJECT OF THE INVENTION

231,147

Claims (2)

Process for the production of polymeric materials having hydroxyether bonds, in particular technical rubber or elasticized epoxy resins, from organic carboxylic compounds, in particular from carboxyl functional end telechelic polymers, characterized in that a catalytic combination consisting of epoxy-containing carboxylic compounds is added to the mixture of polynuclear chromium complexes of organic monocarboxylic acids aliphatic with a number of carbon atoms in the chain> 4, in particular butyric, isobutyric, oleic or aromatic, in particular diisopropylsalieylic acid, and organic electron-donor compounds such as amines, in particular tertiary, by weight No. 5,960: 40 and dosed in an amount of 0.26 parts by weight per 100 parts of the reaction mixture, then the resulting mixture after homogenization and molding force is at a temperature of 100 ° C to 60 ° C. 2. A process for the production of technical rubber according to claim 1, characterized in that the organic electron donor compound is a liquid which is readily miscible with the chromium complex, preferably quinoline. Printed by Moravian Printing Dukes, plant 12, Leninova 21, Olomouc