Method for producing bis-[4-(diphenylsulfonio) phenyl] sulfide bis-MX6

Claim 1

In a method of polymerization of a cationically polymerizable monomer, the steps comprising: A. making a photoinitiator by: (1) forming a first reactant by admixing diphenyl sulfide and chlorine gas in an organic Friedel-Crafts solvent in the present of a Friedel-Crafts catalyst to react the chlorine gas with the diphenyl sulfide and form bis-[4-(diphenylsulfonio)phenyl]sulfide dichloride as an initial product; (2) adding water thereto to hydrolyze the reaction mixture; (3) recovering said bis-[4-(diphenylsulfonio)phenyl]sulfide dichloride from said reaction mixture; (4) admixing said bis-[4-(diphenylsulfonio)phenyl]sulfide bischloride in an aqueous solution with a second reactant having the formula T.MF 6 wherein M is one of phosphorus, antimony or arsenic, T is hydrogen or a metal whose halide salt is water soluble, said reactants reacting to produce a precipitate including bis-[4-(diphenylsulfonio)phenyl]sulfide bis-MF 6 ; (5) recovering said precipitate; and (6) drying said precipitate at a temperature below about 50° C. for at least an initial period to dewater said precipitate and recover a frangible product containing at least 50 percent by weight bis-[4-(diphenylsulfonio)phenyl]sulfide bis-MF 6 based upon solids, said product comprising a photoinitiator; B. admixing said photoinitiator with a cationically polymerizable monomer formulation in an amount equal to 0.5-6.0 percent by weight of the monomer therein; and C. exposing said admixture to a source of electromagnetic radiation to decompose said photoinitiator and produce a Lewis acid to initiate polymerization of said polymerizable monomer.