Novel photoinitiators

A compound of formula (I)

• wherein
• R1 is selected from aryl and heteroaryl, each being unsubstituted or substituted by one or more substituents selected from the group consisting of:
• halogen, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C1-C20 alkoxy, substituted or unsubstituted C1-C20 alkylthio, substituted or unsubstituted (C1-C12alkyl)2amino, morpholino, piperidino, piperazino and N(C1-C12alkyl)piperazino;
• n is from 1 to 7;
• R2 is a group of formula (II)
• wherein
• G comprises residue of monomeric, oligomeric or polymeric polyols G-(OH)m+n+p;
• m is 1 to 7;
• p is 0 to 6;
• m+n+p is from 2 to 8;
• R3 comprises CH2═CH—C(═O) or CH2═C(CH3)—C(═O);
• the wavy line in formula (II) indicates a linking bond to the compound of formula (I);
• Z is selected from structure (i), (ii) and (iii)
• wherein
• X comprises O, S or C(R4)(R5);
• Y comprises O, S, C(R4)(R5) or NR6;
• R4 and R5 each comprise H, C1-C12 alkyl, OH or C1-C10 alkoxy;
• R6 comprises H C1-C8 alkyl;
• and the wavy line in each of structure (i), (ii) and (iii) indicate bonds linking to the keto groups of formula (I).