Bis benzoyl sensitizers for photopolymerization or photo cross linking process and composition

Claim 1

In a method for the photopolymerisation of unsaturated compounds or for the photochemical crosslinking of polyolefins employing a sensitizer, the improvement according to which the sensitizer is a compound of the formula ##STR58## wherein Ar is a member selected from the group consisting of phenyl, naphthyl, phenanthryl, anthracyl, diphenylyl, chlorophenyl, bromophenyl, dichlorophenyl, mesityl, isopropylphenyl, phenoxyphenyl, cyanophenyl, p-nonylphenyl, hydroxyphenyl, tolyl, tert-butylphenyl, xylyl, isopropylchlorophenyl, methoxyphenyl, ethoxyphenyl, phenoxyphenyl, chlorotolyl, bromoxylyl, methylthiophenyl, phenylthiophenyl, butylsulfophenyl, phenylsulfophenyl, ethoxycarbonylphenyl, tert-butoxycarbonylphenyl, methylaminosulfophenyl, dipropylaminosulfophenyl, dimethylaminophenyl, benzoylaminophenyl and acetylaminophenyl, X represents --OR 6 , X' represents ##STR59## R 1 represents (a) C 1 -C 8 alkyl, (b) C 1 -C 8 alkyl substituted by --OH, Oalk, C 2 -C 8 acyloxy, --NR 4 R 5 , --COOalk or --CN, (c) C 3 -C 4 alkenyl, (d) C 5 -C 6 cycloalkyl or (e) C 7 -C 9 phenylalkyl, R 2 has one of the meanings assigned to R 1 or represents a --CH 2 CH 2 R 13 group, or together with R 1 represents C 2 -C 8 alkylene or C 3 -C 9 oxaalkylene or C 3 -C 9 azaalkylene, R 3 represents a direct bond, C 1 -C 6 alkylene, C 2 -C 6 oxaalkylene, C 2 -C 6 thiaalkylene, S-oxathiaalkylene or S-dioxathiaalkylene, phenylene, diphenylene or a -phenylene-T-phenylene group, or together with both substituents R 2 and both carbon atoms to which these substituents are attached, forms a cyclopentane, cyclohexene, endomethylenecyclohexane or cyclohexane ring, T represents --O--, --S--, --SO 2 --, --CH 2 --, --CH 2 --CH 2 --, --CH 2 OCH 2 -- or --CH═CH--, R 4 represents (a) C 1 -C 12 alkyl, (b) C 2 -C 4 alkyl substituted by --OH, Oalk or --CN, (c) C 3 -C 5 alkenyl, (d) cyclohexyl, (e) C 7 -C 9 phenylalkyl, (f) phenyl or (g) phenyl which is substituted by Cl, alk, OH, Oalk or --COOalk, R 5 represents (a) C 1 -C 12 alkyl, (b) C 2 -C 4 alkyl which is substituted by --OH, Oalk or --CN, (c) C 3 -C 5 alkenyl, (d) cyclohexyl or (e) C 7 -C 9 phenylalkyl, or R 4 and R 5 together represent C 4 -C 5 alkylene which can be interrupted by --O-- or ##STR60## R 6 represents (a) hydrogen, (b) C 1 -C 12 alkyl, (c) C 1 -C 8 alkyl which is substituted by Cl, Br, OH, Oalk, Salk, C 2 -C 8 acyloxy, --COOalk, CONHalk, --CON(alk) 2 or CN, (d) C 3 -C 5 alkenyl, (e) cyclohexyl, (f) benzyl, (g) phenyl, (h) phenyl substituted by Cl or alk, or (i) 2-tetrahydropyranyl, R 13 represents --CONH 2 , --CONHalk, --CON(alk) 2 , --P(O)(Oalk) 2 , 2-pyridyl or 2-oxo-1-pyrrolidinyl, and R 14 represents C 1 -C 4 alkyl, --CH 2 CH 2 CN or --CH 2 CH 2 COOalk.