Photopolymerization by means of sulfoxonium salts

A cationically photopolymerizable composition comprising

• (a) a compound, or mixture of compounds, capable of being transformed into a higher-molecular weight material under the influence of a cationic catalyst, which is a 1,2-epoxide, a vinyl monomer or prepolymer, an aminoplast, a phenoplast, an oxetane, tetrahydrofuran or a thi-irane, and
• (b) an effective amount of a carbamoylsulfoxonium salt of the formula ##STR14## where p is zero or 1,
• q is an integer of from 1 to 4,
• Ar denotes an aromatic group of valency q, having from 4 to 25 carbon atoms and being directly linked through a carbon atom thereof to the carbon atom of the indicated adjacent carbonyl group if p is 1 or to the indicated nitrogen atom if p is zero,
• R.sup.6 denotes a hydrogen atom or a group of formula
• --COR.sup.9 VII
• or
• --CONH(CO).sub.r --R.sup.10 VIII
• R.sup.7 denotes an alkyl group of 1 to 18 carbon atoms, an alkenyl group of 2 to 6 carbon atoms, a cycloalkyl group of 3 to 8 carbon atoms, a cycloalkylalkyl group of 4 to 10 carbon atoms, an aryl group of 4 to 24 carbon atoms, or an aralkyl group of 5 to 16 carbon atoms,
• R.sup.8 has the same meaning as R.sup.7, but may independently represent a dialkylamino group of 2 to 6 carbon atoms or, if R.sup.7 denotes a said alkyl group, it may independently represent an arylamino group of 4 to 8 carbon atoms,
• R.sup.9 denotes a monovalent saturated or ethylenically unsaturated radical of 1 to 12 carbon atoms, directly linked through a carbon atom thereof to the --CO-- group shown in formula VII,
• r is zero or 1,
• R.sup.10 denotes a monovalent saturated or ethylenically unsaturated radical of 1 to 12 carbon atoms, directly linked through a carbon atom thereof to, if r denotes zero, the indicated nitrogen atom, or, if r denotes 1, the carbon atom of the indicated adjacent carbonyl group,
• t represents 1, 2, or 3, and
• Z.sup.t- denotes a t-valent anion which is Cl.sup.-, Br.sup.-, NO.sub.3.sup.-, HSO.sub.4.sup.-, HSO.sub.3.sup.-, ClO.sub.4.sup.-, CF.sub.3 SO.sub.3.sup.-, CF.sub.3 COO.sup.-, C.sub.6 H.sub.5 SO.sub.3.sup.-, CH.sub.3 C.sub.6 H.sub.4 SO.sub.3.sup.-, H.sub.2 PO.sub.4.sup.-, SO.sub.4.sup.--, PO.sub.4.sup.---, SbF.sub.5 (OH).sup.-, CH.sub.3 SO.sub.4.sup.- or an anion of formula
• MX.sub.n.sup.- XI
• where
• M denotes an atom of a metal or of a metalloid,
• X denotes a halogen atom, and
• n is 4, 5, or 6 and is one more than the valency of M.