GB955491A - Improvements relating to polyepoxide resins - Google Patents

Abstract

Curable compositions comprise a polyepoxide and as sole curing agent 2-50% of its weight of at least one boron ester of formula Rx1B(OR)3-x, in which R is alkyl of 3-20 carbon atoms, unsaturated aliphatic radical of 1-12 carbon atoms, an alkyl radical of 1-12 carbon atoms with aromatic or heterocyclic substituents, aryl, alkaryl, haloaryl, or a heterocyclic radical; R1 is alkyl of 1-20 carbon atoms, aralkyl, haloalkyl, unsaturated aliphatic hydrocarbon of 1-12 carbon atoms, aryl, alkaryl, haloaryl or a heterocyclic radical, and x is 0, 1 or 2. Conventional additives may be included in the compositions. Examples describe the curing of a polyglycidyl ether of bisphenol A, an epoxidized soyabean oil, an epoxidized polybutadiene, or an ester of 2-methyl-4, 5-epoxy-1-hydroxymethyl cyclohexane and 2-methyl-4, 5-epoxy-cyclo-hexan-1-carboxylic acid with curing agents selected from tricyclohexyl borate, tri-n-hexyl borate, triallyl borate, diethyl-4-chlorobenzeneboronate, tri-1-ethynylcyclohexyl borate, tri-o-chlorophenyl borate, a mixture of tri-o-cresyl borate and tri-n-hexyl borate, diisopropylbenzeneboronate, diphenyl ethane boronate, diphenyl propane boronate, tri-furfuryl borate, tri-o-cresyl borate, stearyl di-6-chloropropylborinate, ditetrahydrofurfuryl docecaneboronate, allyl diethylborinate, triphenyl borate, stearyl diethylborinate, dibutyl-p-ethylbenzeneboronate, and tribenzyl borate. Example XII describes the curing of the ester of 3-methyl-4, 5-epoxy-1-hydroxymethyl cyclohexane and 2-methyl-4, 5-epoxycyclohexan-1-carboxylic acid with dimethyl acetyleneboronate yields a flexible foamed resin. Other suitable boron curing agents are mentioned by name.