PURPOSE: To produce the titled resin being excellent in heat resistance, chemical resistance and flexibility and having an improved compatibility with various curing agents, by cocondensing a novolak epoxy resin with a precondensate of an epoxy resin and an excess of a polyhydric phenol.
CONSTITUTION: A precondensate (A) is obtained by adding a polyhydric phenol (e.g., bisphenol A) to an epoxy resin prepared from a polyhydric phenol and epichlorohydrin so that at least one phenolic hydroxyl group is present per epoxy group and reacting the mixture at 50W260°C. Then, component A is cocondensed with a novolak epoxy resin (B) obtained by reacting epichlorohydrin with a phenolic resin obtained from a (substituted) phenol and a formaldehyde- supplying substance so that 0.01W0.5 phenolic hydroxyl group of component A is present per epoxy group of component B.
ARIGA NAGAROU
SEKIGUCHI HISAFUMI
KONISHI AKIRA
