Patent ID: 7642296

Claim:
A photoinitiator of formula I or II wherein R 1 and R 2 are each independently of the other C 1 -C 8 alkyl, C 3 -C 6 alkenyl, benzyl, —CH 2 —C 6 H 4 —(C 1 -C 4 alkyl) or phenyl, or R 1 and R 2 together are unbranched or branched C 2 -C 9 alkylene; and R 3 , R 4 , R 5 and R 6 are each independently of the others hydrogen, C 1 -C 8 alkyl, C 3 -C 6 alkenyl, benzyl, —CH 2 —C 6 H 4 —(C 1 -C 4 alkyl) or phenyl; or R 3 and R 4 together and/or R 5 and R 6 together are unbranched or branched C 3 -C 9 alkylene; A is —O—R 9 , A″ is —O—R 9 or hydrogen, X is —O—R 10 , R 9 is hydrogen, —Si(C 1 -C 6 alkyl) 3 , C 1 -C 12 alkyl, R 23 , C 2 -C 18 acyl, —CO—NH—C 1 -C 12 alkyl, —CO—C 1 -C 4 alkoxy, C 2 -C 20 hydroxyalkyl, C 2 -C 20 methoxyalkyl, 3-(C 1 -C 18 alkoxy)-2-hydroxy-propyl, 3-[1,3,3,3-tetramethyl-1-[(trimethylsilyl)oxy]disiloxanyl]-propyl, 2,3-dihydroxy-propyl or linear or branched C 2 -C 21 hydroxyalkyl or (C 1 -C 4 alkoxy)-C 2 -C 21 alkyl the carbon chain of which is interrupted by from one to nine oxygen atoms, R 10 is hydrogen, —Si(C 1 -C 6 alkyl) 3 , or benzyl, R 23 is, independently of formula I, a radical