A new epoxy/episulfide resin system for electronic applications - 2: pot life and prepreg storage life evaluation

A new epoxy/episulfide thermosetting resin was evaluated, using a dicyandia mide (DICY) curing agent. The system was found to exhibit a longer pot life and prepreg storage life than the standard epoxy system. The properties ar e attributable to the change in reaction mechanism caused by the addition o f episulfide. The reaction mechanisms were studied using a mono-functional model compound system; the extent of episulfde-amine reaction is relatively high in the epoxy/episulfide system relative to epoxy-amine. A tert-amine salt is probably formed which does not act as a catalyst for the epoxy ring opening, resulting in a greater pot life.