Method for curing an epoxy resin with a polyamide derived from a polyamide and a substantially non-cyclic dimer acid

摘要

An improvement is proposed in the curing method of an epoxy resin by the admixture of a polyamide as a crosslinking curing agent, in which the curing agent as well as the epoxy resin composition with admixture of the curing agent has an outstandingly low viscosity as compared with the use of a conventional polyamide to facilitate handling. The improvement can be obtained by using, as the polyamide, a condensation reaction product between (A) an alkylene polyamine having 4 to 20 carbon atoms in a molecule and (B) a dimeric acid mixture containing at least 50% by weight of a non-cyclic dimeric acid or an alkyl ester thereof represented by the general formula ##STR1## in which each R is, independently from the other, a hydrogen atom or a C.sub.1-4 alkyl group obtained by the dimerization reaction of oleic acid or an alkyl ester thereof. When flexibility or bendability is desired of the cured epoxy resin, the condensation reaction is performed, in addition to the reactants (A) and (B), with admixture of a C.sub.5-21 monobasic carboxylic acid or an alkyl ester thereof.