Photocurable compositions

Claim 1

A photocurable composition consisting of (a) one or more ethylenically unsaturated, photocurable compounds, (b) at least one photo-initiator of the formula I or II ##STR4## in which n is 1 or 2 and, if n is 1, Ar is unsubstituted phenyl or phenyl substituted by one or more of the radicals F, Cl, Br, C 1 -C 12 alkyl, -OAlk, phenyl, -Ophenyl, --SAlk, --SCH 2 CH 2 OH or -Sphenyl, or indanyl or tetrahydronaphthyl, and Alk is a lower alkyl radical having 1-4 C atoms, and if n is 2 Ar is C 6 -C 12 arylene or a group -phenylene-T-phenylene-, in which T is --O--, --S--, --CH 2 -- or --CH 2 CH 2 --, X is one of the groups --NR 4 R 5 , --OR 6 or --OSiR 7 (R 8 ) 2 , R 1 is unsubstituted C 1 -C 8 alkyl or C 1 -C 8 alkyl substituted by --OH, OAlk, C 2 -C 8 acyloxy, --NR 4 R 5 , --COOAlk or --CN, or C 3 -C 4 alkenyl, C 5 -C 6 cycloalkyl or C 7 -C 9 phenylalkyl, R 2 has one of the meanings defined for R 1 or together with R 1 is C 2 -C 8 alkylene or C 3 -C 9 oxa- or aza-alkylene, R 3 is a direct bond, C 1 -C 6 alkylene, C 2 -C 6 oxa-alkylene, C 2 -C 6 thia-, S-oxothia- or S-dioxothiaalkylene, phenylene, diphenylene or a group -phenylene-T-phenylene-, or together with the two substituents R 2 and the two C atoms to which these substituents are bonded forms a cyclopentane, cyclohexane, endomethylenecyclohexane or cyclohexane ring, R 4 is C 1 -C 12 alkyl or C 2 -C 4 alkyl which is substituted by --OH or OAlk, R 5 is C 1 -C 12 alkyl or C 2 -C 4 alkyl which is substituted by OH or OAlk, or together with R 4 is C 4 -C 5 alkylene, which can be interrupted by --O-- or --NR 9 --, R 6 is hydrogen, C 1 -C 12 alkyl, C 1 -C 8 alkyl substituted by Cl, Br, OH, OAlk, SAlk, C 2 -C 8 acyloxy, --COOAlk, --CONHAlk, --CON(Alk) 2 or CN, or C 3 -C 5 alkenyl, cyclohexyl, benzyl, unsubstituted phenyl or phenyl substituted by Cl or Alk, or 2-tetrahydropyranyl, R 7 and R 8 are identical or different and are C 1 -C 4 alkyl or phenyl and R 9 is C 1 -C 4 alkyl, --CH 2 CH 2 CN or --CH 2 CH 2 COOAlk, and (c) at least one light stabiliser from the category of the polyalkylpiperidine derivatives.