POLYCYCLIC PHOTOINITIATORS

Compounds of the formula (I) (I), wherein X is O, S, a direct bond or CR16R17; Y is O or S; R1, R2, R3, R4, R5, R6, R7 and R8 for example are hydrogen, halogen, C1-C4alkyl, or a group of formula (II) or (III) (II) (III) provided that either (i) one of R1, R2, R3, R4, R5, R6, R7 or R8 is a group of formula (II) or (III); or (ii) one of R1, R2, R3 or R4 is a group of formula (II) or (III) and one of R5, R6, R7 or R8 is a group of formula (II) or (III); R9 and R10 independently of each other are C1-C4alkyl or together with the C atom to which they are attached form a 5-membered, 6-membered or 7-membered carbocyclic ring; R11 is hydrogen, C1-C4alkyl, C5-C7cycloalkyl, 2-tetrahydropyranyl or Si(C1-C4alkyl)3; R12 and R13 for example are C1-C4alkyl, C2-C12alkenyl, phenyl-C1-C4alkyl, phenyl-C1- C4alkyl which is substituted by C1-C4alkyl, R14 and R15 independently of each other are C1-C4alkyl, C5-C7cycloalkyl, or together with the N atom to which they are attached form a 5-membered, 6-membered or 7- membered ring, which may contain additional heteroatoms O, S or N; R16 and R17 for example are hydrogen, C1-C8alkyl, C5-C7cycloalkyl, phenyl-C1-C4alkyl, phenyl; are effective photoinitiators.