Epoxy-acrylate blend pressure-sensitive thermosetting adhesives
AssigneeMinnesota Mining and Manufacturing Company
InventorsShuichi Kitano, Kiyoshi Ogata, Shinobu Sato
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Abstract
The invention relates to a pressure-sensitive thermosetting adhesive comprising from about 30% to about 80% by weight of a photopolymerizable prepolymeric or monomeric syrup containing an acrylic ester and a polar copolymerizable monomer, from about 20% to about 60% by weight of an epoxy resin or a mixture of epoxy resins containing no photopolymerizable groups, from about 0.5% to about 10% by weight of a heat-activatable hardener for the epoxy resin, from about 0.01% to about 5% of a photoinitiator, and from 0% to about 5% of a photocrosslinking agent. In a preferred embodiment, imidazoles and thermally expandable thermoplastic microspheres are utilized in the inventive adhesive formulation.
Claims20
A pressure-sensitive thermosetting adhesive which is the photopolymerization reaction product of a blend consisting essentially of:
- (a) from about 30% to about 80% by weight of a photopolymerizable monomeric or prepolymeric syrup containing an acrylic acid ester of a nontertiary alcohol, and a moderately polar copolymerizable monomer;
- (b) from about 20% to about 60% by weight of an epoxy resin or a mixture of epoxy resins containing no photopolymerizable groups;
- (c) from about 0.5% to about 10% by weight of a heat-activatable hardener for the epoxy resin;
- (d) from about 0.01% to about 5% of a photoinitiator;
- and (e) from 0% to about 5% of a photocrosslinking agent.
Dependencies are inferred from the claim text.