Thermosetting pressure-sensitive adhesive and adhesive sheet thereof

Abstract

A thermosetting pressure-sensitive adhesive which can obtain the high rate of polymerization without a decrease in the molecular weight by photopolymerization, thereby show the tackiness at ordinary temperatures to permit easy temporary adhesion to an adherend, can be cured by heating for a short period of time to exhibit strong adhesive strength and high heat resistance, and is excellent in storage stability before heating, comprising a photopolymerized product of a composition comprising a) 100 parts by weight of a monomer mixture comprising 70% to 99% by weight of an alkyl (meth)acrylate whose alkyl group has 2 to 14 carbon atoms on average, and 1% to 30% by weight of a monoethylenic unsaturated acid copolymerizable therewith based on the monomer mixture, b) 0.01 part to 20 parts by weight of a cleavage type photopolymerization initiator having 3 or more peroxide groups in its one molecule, c) 5 parts to 30 parts by weight of an epoxy resin, and not substantially containing a curing agent for the epoxy resin as ingredient (c).

Dependencies are inferred from the claim text.