Curable epoxy compositions containing aromatic onium salts and hydroxy compounds

Claim 1

Photocurable compositions consisting essentially of (A) an epoxy resin polymerizable to a higher molecular weight state containing a hydroxy functional flexibilizer, and (B) from 0.1% to 15% by weight of a radiation sensitive aromatic onium salt of a Group VIa element capable of effecting the cure of (A) by exposure to radiant energy, where the radiation sensitive aromatic onium salt has the formula, [(R).sub.a (R.sup.1).sub.b (R.sup.2).sub.c X].sub.d.sup.+ [MQ.sub.e ].sup.-(e-f), R is a monovalent aromatic organic radical, R 1 is a monovalent organic aliphatic radical selected from alkyl, cycloalkyl and substituted alkyl, R 2 is a polyvalent organic radical forming a heterocyclic or fused ring structure selected from aliphatic radicals and aromatic radicals, X is a Group VIa element selected from sulfur, selenium and tellurium, M is a metal or metalloid, Q is a halogen radical, a is a whole number equal to 0 to 3 inclusive, b is a whole number equal to 0 to 2 inclusive, c is a whole number equal to 0 or 1 where the sum of a+b+c is a value equal to 3 or the valence of X, d=e-f, f=valence of M and is an integer equal to from 2 to 7 inclusive, e is >f and is an integer having a value up to 8.