CS218769B1 - Process for preparing a modified isocyanurate resin - Google Patents

Abstract

The invention relates to a method for preparing a modified isocyanurate resin, which is a suitable electrical insulating material, and solves the problem of preparing a heat-resistant and sufficiently reactive resin from non-toxic raw materials. The essence of the invention is the preparation of isocyanurate resin by polycondensation of tris-(2-hydroxyethyl)isocyanurate with isophthalic acid, glycerin, pentaerythritol, unsaturated aliphatic carboxylic acids with 16 to 20 carbon atoms and 2 to 3 double bonds and optionally with aliphatic dicarboxylic acid with 6 to 9 carbon atoms. The invention can be used in the production of electrical insulating varnishes.

Description

The present invention relates to a process for preparing a modified isocyanurate resin and solves the problem of producing a heat-resistant resin for electrical insulating purposes manufactured using a variety of raw materials and yet sufficiently reactive with phenol-formaldehyde or melamine-formaldehyde thermosets.

It is known that heat-resistant resins based on modified oligoesterimides can be prepared, as described, for example, in British Patent Specification No. 973,377 or Czechoslovakian Authorization Nos. 147,833, 147,939, 180,356 and 180,258. However, these products have limited reactivity with phenolformaldehyde. thermosets and in particular require aromatic diamines for their preparation which have recently been found to be highly toxic and have a potential for carcinogenic effects. It is further known to prepare the modified isocyanurate resins described in U.S. Patent No. 3,523,820 based on unsaturated aliphatic carboxylic acids, isophthalic acid and tris- (2-hydroxyethyl) isocyanurate, of which at most half can be replaced by another aliphatic triol or diol. However, these products show low reactivity with ifenolformaldehyde thermosets and require temperatures above 150 ° C to be fully crosslinked. In addition, they have a limited cross-linking ability by reaction with air oxygen and are economically disadvantageous due to the high content of isocyanurate derivatives.

The essence of a process for preparing a modified isocyanurate resin by reacting tris (2-hydroxyethyl) isocyanurate, isophthalic acid and unsaturated carboxylic aliphatic acids, which removes the above drawbacks is that 1 mole of isophthalic acid with 0.3 to 0.4 mole of tris- (2-hydroxyethyl) isocyanurate, 0.15 to 0.30 moles of pentaerythritol, 0.75 to 0.85 moles of glycerin, 0.75 to 0.85 moles of mixed monocarboxylic acids of drying oils of 16 to 20 carbon atoms and 5.8 to 9.5 meq of double salts bonds / g and optionally to 0.1 mol of an aliphatic dicarboxylic acid of 6 to 9 carbon atoms are heated together at a temperature of 150 to 235 ° C with removal of the reaction water.

The modified isocyanurate resins prepared by the process according to the invention have an advantage over the known types of resins in the negligible toxicity of the raw materials used, in very good solubility in readily available solvents of low to medium polarity and in increased curing ability by both air oxygen and especially heat or catalytically accelerated reaction with phenol-formaldehyde condensates.

The modified isocyanurate resins prepared by the process of the present invention are soluble in aromatics, mixtures thereof with alcohols and aliphatic hydrocarbons, in esters and other solvents of lower polarity. They contain unsaturated groups capable of reacting with airborne oxygen and a system of unsaturated groups and highly reactive hydroxyl groups enabling their rapid curing by reaction with phenol-formaldehyde or melamine-formaldehyde condensates, with polyisocyanates or polyarylurethanes at temperatures of 120 to 150 ° C and organosilicon compounds or organotitanium compounds up to 180 ° C.

Example 1

166.136 g (1 mole of isophthalic acid, 90.920 g (0.348 mole) of tris- (2-hydroxyethyl) isocyanurate (THEICJ), 20.831 g (0.153 mole) of pentaerythritol, 74.138 g (0.805 mole) of glycerin, 14.615 g (0.100 mole) of -adipic acid and 206.177 g (0.80 mol) of mixed acids obtained by hydrolyzing soybean oil and containing 5.8 meq / g of double C = C bonds are heated to 150 ° C with stirring and further heated at a rate of 0.5 ° C / min. After reaching 225 ° C, the temperature is maintained for 2 hours to give 516.0 g of a resin containing 0.294 meq COOH / g and 2.368 meq OH / g, soluble in xylene-butanol 3: 1 A mixture of 43.0% by weight of this product, 24.1% by weight of xylene, 8.0% by weight of butanol and 24.9% by weight of reactive phenol-formaldehyde resol, known as Vlaphen 881C gels at 125 ° C for 2.5 It provides a polymer coating resistant to cr short-term heating up to 250 ° G and permanent thermal load at 160 ° C.

Example 2

166.136 g (1.0 mol) isophthalic acid, 78.379 g THEIC (0.300 mol), 34.038 g (0.25 mol) pentaerythritol, 78.282 g (0.85 mol) glycerine, 193.05 g (0.75 mol) refined mixtures of soybean oil monocarboxylic acids containing 0.61.10 ^-2 equiv. CC / g is heated together as described in Example 1. 497.5 g of a resin product of 0.317 meq are obtained. COOH / g 6.351 meq. OH / g, soluble in 3: 1 xylene-butanol. The lacquer prepared from this product in the same manner as in Example 1 gels at 125 ° C for 3.6 hours. It provides a polymer coating at the same temperature in 18 hours, resistant to heat shock at 255 ° C and prolonged heating at 167 ° C.

Example 3

166.136 g (1.0 mol) of isophthalic acid,

104,506 g (0,4 mol) THEIC, 34,038 g (0,25 mol) pentaerythritol, 69,073 g (0,75 mol) glycerin, 217,09 g (0,85 mol) of monocarboxylic acids obtained by hydrolysis218769 β

% of dehydrated castor oil and containing 9.5 meq. C = C / g, was heated together as described in Example 1. 536.9 g of a 0.262 meq resin product was obtained. COOH / ga 3,734 meq. OH / g, soluble in xyleine. Varnishes prepared from this product in the same manner as in Example 1, a gel for 2.4 hrs. At 125 C and gives ^Q at this temperature for 14 hours the polymeric coating to withstand short-term heating at 262 ^C C and prolonged heating at 172 ° C.

Example 4

166.136 g (1.0 mol) of isophthalic acid, 90.92 g (0.348 mol) of THEIC, 40.845 g (0.3 mol) of pentaerythritol, 73.678 g (0.8 mol) of glycerin, 20.225 g (0.1 mol) of acid sebacic acid and 191.55 g (0.75 mol) of distilled castor oil monocarboxylic acids containing 9.3 meq C = C / g are heated together with stirring at 150 to 230 ° C at a rate of 0.4 ° C / min. Upon reaching the above-mentioned temperature, the reaction mixture was held at 230-235 ° C for 90 minutes to give a resin product of 0.278 meq COOH / g and 3.489 meq OH / g in an amount of 527.4 g. by the method of Example 1, it gelled for 1.8 hours at 2 (35 ° C) and provided for 8 hours at this temperature with a polymer coating resistant to short term superheat at 255 ° C and long term heat load at 162 ° C.

Claims (1)

A process for preparing a modified isocyanurate resin by reacting tris (2-hydroxyethyl) isocyanurate, isophthalic acid and unsaturated carboxylic aliphatic acids, characterized in that 1 mole of isophthalic acid with 0.3 to 0.4 moles of tris (2-hydroxyethyl) isocyanurate, 0.15 to 0 , 30 mole of pentaerythritol, 0.75 to 0.85 mole of glycerin, OF THE INVENTION 0.75 to 0.85 moles of mixed monocarboxylic aliphatic acids of drying oils of 16 to 20 carbon atoms and 5.8 to 9.5 meq. of double bonds / g and optionally up to 0.1 mol of an aliphatic dicarboxylic acid of 6 to 9 carbon atoms are heated together at a temperature of 150 to 235 ° C with removal of the reaction water.