Patent ID: 7297724

Claim:
A method of photopolymerization comprising irradiating a photopolymerizable composition with actinic radiation until the photopolymerizable composition gels or hardens, said photopolymerizable composition comprising: an ethylenically on saturated monomer; an arylsulfinate salt having an anion of Formula I Ar 1 —SO 2 − I and having a cation that contains at least one carbon atom and either a positively charged nitrogen atom or a positively charged phosphorus atom, wherein Ar 1 is a substituted phenyl, an unsubstituted or substituted C 7-30 aryl or an unsubstituted or substituted C 3-30 heteroaryl, said substituted Ar 1 having a substituent that is an electron withdrawing group or an electron withdrawing group in combination with an electron donating group; and a triarylsulfonium salt, wherein the polymerizable composition generates a radical upon exposure to actinic radiation and wherein the photopolymerizable composition is free of an additive that competitively absorbs actinic radiation.