Cationically polymerizable compositions containing photodecomposable aromatic iodonium salts

Claim 1

Cationically polymerizable compositions consisting essentially of (A) a monomeric or prepolymeric cationically polymerizable organic material free of oxirane oxygen selected from vinyl organic monomers, vinyl organic prepolymers, cyclic organic ethers, cyclic organic esters, cyclic organic sulfides, cyclic amines and organosilicon cyclics, and (B) an effective amount of photodecomposable aromatic iodonium salt capable of effecting the polymerization of (A) when exposed to radiant energy where said photodecomposable aromatic iodonium salt has the formula, [(R).sub.a (R.sup.1).sub.b X].sub.c.sup.+ [MQ.sub.d ].sup.-(d-e) where R is a monovalent aromatic organic radical, R 1 is a divalent aromatic organic radical, X is a halogen cation, M is a metal or metalloid atom, Q is a halogen atom, a is a whole number equal to 0 to 2, b is a whole number equal to 0 or 1, and the sum of a +b is equal to 2 or the valence of X, c=d-e e=valence of M and is an integer equal to 2-7 inclusive, d is an integer having a value greater than 3.