Propiophenone derivatives as photoinitiators for photopolymerization

摘要

Propiophenones of the formula I (I) in which R1 is hydrogen or C1-C4-alkyl, -Si(CH3)3, allyl or benzyl, R2 is hydrogen, C1-C8-alkyl, C1-C4-alkyl which is substituted by C1-C4-alkoxy or -OH, -(CH2-CH2-O)n-R5 where n is 2 to 20 and R5 is H or C1-C4-alkyl, -Si(CH3)3, benzyl, C3-C6-alkenyl, C3-C4-alkynyl or 2-tetrahydrofuranyl, or R1 and R2 together are a C1-C6-alkylidene radical or a C2-C6-alkylidene radical which is substituted by hydroxyl, C1-C4-alkoxy or phenyl, a linear or branched C2-C6-alkanediyl radical, a benzylidene, cyclopentylidene or cyclohexylidene radical or a 2,2,2-trichloroethylidene, 2-furylimethylidene or dimethylsilylidene radical, R3 is phenyl which is unsubstituted or substituted by one or more -Cl, C1-C4-alkyl, C1-C4-alkoxy or C1-C4-alkylthio radicals, and is also benzoylphenyl, phenoxyphenyl or phenylthiophenyl, R4 is C1-C4-alkyl, or phenyl which is unsubstituted or substituted by one or more -Cl, C1-C4-alkyl or C1-C4-alkoxy radicals, and R5 is hydrogen or C1-C4-alkyl, or R4 and R5 together are a trimethylene or tetramethylene radical, and R6 is hydrogen, C1-C4-alkyl, -CCl3 or phenyl, subject to the condition that, if R2, R5 and R6 at the same time are hydrogen and R3 and R4 ar at the same time phenyl, R1 must not be hydrogen or C1-C4-alkyl, also, if R3 and R4 at the same time are phenyl and R5 and R6 are at the same time hydrogen, R1 and R2 together must not be alkylidene or benzylidene, and also, if R3 and R4 at the same time are p-methoxyphenyl and R2, R5 and R6 are at the same time hydrogen, R1 must not be hydrogen, and, finally, if R2 and R5 at the same time are hydrogen and R3, R4 and R6 are at the same time phenyl, R1 must not be hydrogen, are valuable initiators for the photopolymerization of ethylenically unsaturated compounds.