Epoxy resins containing imido rings, production process thereof, and epoxy resin compositions containing the same

Abstract From the Canadian patent

An epoxy resin is obtained by reacting an epihalohydrin with an imido-ring-containing diphenol represented by the following formula (I): ( I ), wherein R represents an aliphatic group having at least two carbon atoms, an alicyclic group, a monocyclic aryl group, a fused polycyclic aromatic group or a, non-fused polycyclic aromatic group formed of aromatic groups coupled together directly or via a linking member and the two hydroxyl groups are each bonded to a meta position or the para position. In the epoxy resin, at least 50% of the hydroxyl groups of molecules of the diphenol have been epoxidized.