Patent ID: 10017604

Abstract:
Provided are a modified epoxy resin and a modified epoxy resin whose cured products exhibit good heat resistance and dielectric properties, methods for producing these, a curable resin composition, a cured product of the curable resin composition, and a printed wiring substrate. A modified phenolic resin comprises a phenolic resin structure (A), wherein at least one aromatic nucleus (a) in the phenolic resin structure (A) has, as a substituent, a structural segment (1) represented by structural formula (1) below: In the formula, Ar each independently represent a phenyl group, a naphthyl group, or a structural segment having, on an aromatic nucleus of a phenyl or naphthyl group, at least one substituent selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, a phenyl group, and an aralkyl group.