Patent ID: 7919550

Claim:
A photosemiconductor encapsulating resin composition having a glass transition temperature of 130° C. or more upon hardening and consisting of the following components (A), (B), (C), and (D): (A): a (meth)acrylic polymer containing an epoxy group having an epoxy equivalent weight of 150 to 4500 g/equivalent polymerized from an epoxy group-containing monomer and from about 10 to 80 mol % of at least one (meth)acrylic monomer other than the epoxy group-containing monomer, the (meth)acrylic monomer selected from the group consisting of alkyl(meth)acrylate having a linear alkyl group having about 1 to 20 carbon atoms; alkyl(meth)acrylate having a branched alkyl group having about 3 to 20 carbon atoms; alkyl(meth)acrylate having a saturated cyclic aliphatic alkyl group having about 5 to 20 carbon atoms; and (meth)acrylonitrile (B): an alicyclic carboxylic anhydride, (C): a hardening accelerator, and (D): an antioxidant, selected from the group consisting of (i) a phenol-based antioxidant and (ii) a phenol-based antioxidant and a sulfur-based antioxidant; wherein the content of a constituent unit derived from the (meth)acrylic monomer of (A) is about 10 to 80 mol %.