Patent ID: 7442729

Claim:
An epoxy resin composition comprising: a compound having two or more epoxy groups in one molecule, a compound having two or more phenolic hydroxyl groups in one molecule, and a curing accelerator for promoting the curing reaction of the epoxy resin composition, wherein the curing accelerator comprises trisubstituted phosphoniophenolate or a salt thereof, wherein the trisubstituted phosphoniophenolate is represented by the following general formula (1): wherein R 1 , R 2 and R 3 are the same as or different from one another, and each represents a substituted or unsubstituted monovalent aromatic group or a substituted or unsubstituted monovalent alkyl group; and Ar represents (i) an unsubstituted divalent aromatic group or (ii) a divalent aromatic group substituted with a single substituent, said substituent not being a hydroxyl group; further wherein in the case when said divalent aromatic group is a phenylene group, the oxyanion-O − is located in an ortho or meta position relative to the phosphorus atom.