Patent ID: 6881799

Claim:
A curing agent for epoxy resins, comprising: (a) 30 to 99 parts by weight of a modified phenol resin which is obtained by polycondensing a heavy oil or pitch, a phenol and a carbonyl compound, which is an aldehylde having 5 to 15 carbon atoms or a ketone, in the presence of an acid catalyst, (b) 1 to 70 parts by weight of a thiodiphenol compound represented by the following general formula (II): wherein R 1 's may be the same or different from each other and each represent an alkyl group having 1 to 12 carbon atoms, substituted or nonsubstituted phenyl group, substituted or nonsubstituted aralkyl group or alkoxy group, and p's may be the same or different from each other and each represent an integer of 0 to 3, and (c) 0 to 100 parts by weight of a polyhydric phenol compound having a structure other than the components (a) and (b).