Method of making a unified pressure-sensitive adhesive tape

Claim 1

A process for making a pressure-sensitive adhesive tape comprising a plurality of superimposed layers, at least one outer layer being a pressure-sensitive adhesive layer, contiguous layers defining an interface therebetween, each of said layers comprising a photopolymerized matrix of polymeric chains; said polymeric chains extending from the matrix of one of said layers through said interface into the matrix of a contiguous layer; said polymeric chains comprising polymerized monomers having migrated from the matrix of each contiguous layer prior to polymerization, said process comprising the steps of: (1) preparing a plurality of coatable compositions, each of said coatable compositions comprising at least one photopolymerizable monomer; at least one of said coatable compositions being curable to a pressure-sensitive adhesive state, monomers of each of said coatable compositions being copolymerizable when blended and subjected to photopolymerization conditions; (2) sequentially coating said coatable compositions to provide a plurality of superimposed layers with contiguous layers defining an interface therebetween, with one composition which is curable to a pressure-sensitive adhesive state being coated as a first or last layer; (3) permitting migration of photopolymerizable monomers through said interface between contiguous layers, and (4) subjecting said superimposed layers to irradiation to simultaneously photopolymerize said monomers in each layer, and to provide polymeric chains comprised of copolymers of photopolymerizable monomers originating from contiguous layers extending through said interface therebetween thereby to produce a tape having layers which cannot be delaminated.