Type II polymerizable photoinitiators and curable compositions

摘要

Type II polymerizable photoinitiator according to Formula (I): ** Formula ** in which: A represents a Norrish Type II initiator group and is a substituted or unsubstituted thioxanthone group, L represents a divalent linking group that positions the group Norrish Type II initiator and the CR2R3 group in a position 1-5 to a position 1-8, in which position 1 is defined as the first atom in the aromatic or alicyclic ring of A, to which L is covalently linked, and position 5 to 8 is defined as the carbon atom of the CR2R group, to which L is covalently linked, with the proviso that L does not contain an amine, R1 represents an optionally substituted group selected from the group consisting of an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an alkaryl group, an aryl group and a heteroaryl group, R2 to R6 each independently represent a hydrogen atom or an optionally substituted group selected from the group that it consists of an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an alkaryl group, an aryl group and a heteroaryl group, with the proviso that at least one of R2 to R6 represents a hydrogen atom, any two or three groups of the group selected from R1 to R6 and L may represent the atoms necessary to form a ring of 5 to 8 members, and with the proviso that at least one of L, R1 to R6 and A is substituted by at least one ethylenically unsaturated polymerizable group selected from the group consisting of an acrylate group, a methacrylate group, an acrylamide group, a methacrylamide group, a styrene group, a vinyl ether group, an allyl ether group, an allyl ester group, a vinyl ester group, a maleate group and a maleimide group.