High molecular weight epoxy resin and resinous composition for printed circuit board

摘要

A high molecular weight epoxy resin obtained by polymerization reaction of a difunctional epoxy resin (X) with a dihydric phenol compound (Y) containing 70-100% by weight of bisphenol S in the presence of a catalyst, the high molecular weight epoxy resin being characterized in that a weight average molecular weight thereof is 10,000-200,000. A resinous composition for a printed circuit board, comprising the high molecular weight epoxy resin, an epoxy resin other than the above-mentioned resin and a curing agent as essential components.