Patent ID: 7790812

Claim:
A process for producing an acid anhydride-based epoxy resin curing agent, comprising: heating a mixture comprising a polyvalent carboxylic acid anhydride and a polyester resin in presence of hydrogen gas and a hydrogenation catalyst, wherein the polyester resin comprises at least one structural unit represented by one of general formulas (2) through (4) shown below: (in the formula, R 1 represents a straight-chain, branched or cyclic alkylene group of 2 to 15 carbon atoms, R 2 to R 5 each represent, independently, a hydrogen atom, or a straight-chain or branched alkyl group of 1 to 4 carbon atoms, and two groups selected from R 2 to R 5 may be bonded together to form a ring structure), (in the formula, R 1 represents a straight-chain, branched or cyclic alkylene group of 2 to 15 carbon atoms, R 2 to R 5 each represent, independently, a hydrogen atom, or a straight-chain or branched alkyl group of 1 to 4 carbon atoms, and two groups selected from R 2 to R 5 may be bonded together to form a ring structure), (in the formula, R 1 represents a straight-chain, branched or cyclic alkylene group of 2 to 15 carbon atoms, R 2 to R 5 each represent, independently, a hydrogen atom, or a straight-chain or branched alkyl group of 1 to 4 carbon atoms, and two groups selected from R 2 to R 5 may be bonded together to form a ring structure).