Patent ID: 7235593

Claim:
A process for preparing a prepolymer mixture for a reactive adhesive comprising (a) mixing in the absence of actinic radiation: (i) a catalyst component consisting of from 2 to 50 parts by weight of a cationic photoinitiator chosen from the group consisting of triaryl sulfonium, diaryl iodonium, dialkylphenacylsulfonium and hydroxyphenyl dialkylsulfonium salts having counterions chosen from the group consisting of SbF 6 − , [(C 6 F 5 ) 4 B] − , AsF 6 − , PF 6 − , C 4 F 9 SO 3 − , FSO 3 − , GaF 6 − , (CF 3 SO 2 ) 2 CH − , (CF 3 SO 2 ) 3 C − , BF 4 − and CF 3 SO 3 − ; with (ii) a monomer/oligomer component comprising 1000 parts by weight of one or more of a monomer or oligomer chosen from oxetane monomers, oxirane monomers, oxetane oligomers and oxirane oligomers, said oxirane monomers and oligomers having at least one oxygen or sulfur of an ether or thioether in a position two or three carbons removed from the oxygen of the oxirane, to provide a pre-irradiation mixture, said pre-irradiation mixture containing no ethylenically substituted monomers that can be polymerized by free radicals, and said pre-irradiation mixture having a first viscosity which is less than 500,000 centipoises; and (b) exposing said pre-irradiation mixture to actinic radiation while maintaining the temperature of said mixture such that spontaneous polymerization is not induced and an activated prepolymer mixture is produced, said activated prepolymer mixture having a viscosity that is functionally unchanged from the viscosity of said pre-irradiation mixture.