Photoinitiator combinations

A photoinitiator combination comprising

• (a) 25-50% of by weight at least one compound of formula (I)
• R1 is C1-C4alkyl, C1-C4alkoxy or halogen;
• R2 is hydrogen, C1-C4alkyl, C1-C4alkoxy or halogen;
• R3 is C1-C20alkyl, cyclopentyl, cyclohexyl, phenyl-C1-C4alkyl or a group of formula (III)
• or R3 is naphthyl, biphenylyl or an O—, S— or N-containing 5- or 6-membered heterocyclic ring, the naphthyl, biphenylyl and O—, S— or N-containing 5- or 6-membered heterocyclic ring radicals being unsubstituted or substituted by C1-C4alkyl, C1-C4alkoxy, halogen, C1-C4alkylthio;
• R4, R5, R6, R7 and R8 are each independently of the others hydrogen, halogen, C1-C20-alkyl, cyclopentyl, cyclohexyl, C2-C12alkenyl, C2-C20alkyl interrupted by one or more non-consecutive O atoms, phenyl-C1-C4alkyl, C1-C20alkoxy, or phenyl that is unsubstituted or substituted by one or two C1-C4alkyl or/and C1-C4alkoxy substituents;
• and
• (b) 25-50% by weight at least one compound of formula (II)
• R1 and R2 are as defined above;
• R9 is C1-C20alkyl, cyclopentyl, cyclohexyl, phenyl-C1-C4alkyl, a group of formula (III), naphthyl, biphenylyl or an O—, S— or N-containing 5- or 6-membered heterocyclic ring, the naphthyl, biphenylyl and O—, S— or N-containing 5- or 6-membered heterocyclic ring radicals being unsubstituted or substituted by C1-C4alkyl, C1-C4alkoxy, halogen, C1-C4-alkylthio;
• and
• R10 is C1-C20alkyl, C2-C20alkyl interrupted by one or more non-consecutive O atoms, C1-C20alkoxy, cyclopentyl, cyclohexyl, phenyl-C1-C4alkyl, a group of formula (III), naphthyl, biphenylyl or an O—, S— or N-containing 5- or 6-membered heterocyclic ring, the naphthyl, biphenylyl and O—, S— or N-containing 5- or 6-membered heterocyclic ring radicals being unsubstituted or substituted by C1-C4alkyl, C1-C4alkoxy, halogen, C1-C4alkylthio.