Phosphorus-containing epoxy resin, composition containing phosphorus-containing epoxy resin as essential component, and cured product

摘要

The present invention provides an epoxy resin that has further improved heat resistance, while maintaining conventional adhesion, specifically a phosphorus-containing epoxy resin (A) which is obtained by reacting, as essential components, a phosphorus compound represented by general formula (1), a quinone compound and an epoxy resin (a), and which is characterized in that the epoxy resin (a) is a novolac epoxy resin that has a molecular weight distribution having a dinuclear component content of 15% by area or less, a trinuclear component content of 15-60% by area, and a number average molecular weight of 350-700 as determined by gel permeation chromatography.