Use of aromatic-aliphatic ketones as photo sensitizers

DETAILED DESCRIPTION What is claimed is: 1.
In a method for the photopolymerisation of unsaturated compounds employing a sensitizer, the improvement according to which the sensitizer is a compound of the formula ##STR58## wherein n is 1 or 2, Ar, if n is 1, represents aryl of 6 to 14 carbon atoms, phenyl which is substituted by CN, OH, alk, --Oalk, --Salk, --SO.
sub.
2 alk, --SO.
sub.
2 phenyl, --COOalk, --SO.
sub.
2 NH.
sub.
2, --SO.
sub.
2 Nalk.
sub.
2, --NHalk, --Nalk.
sub.
2, --Ophenyl, NHCOalk, --SO.
sub.
2 NHalk or --CO.
sub.
2 N(alk).
sub.
2, or represents thienyl, pyridyl or furyl, wherein alk represents a lower alkyl radical of 1 to 4 carbon atoms, and, if n is 2, represents arylene of 6 to 12 carbon atoms or a phenylene-T-phenylene group, X represents one of the groups --NR.
sup.
4 R.
sup.
5, --OR.
sup.
6, --O--Si(R.
sup.
7)(R.
sup.
8).
sub.
2, hydroxymethoxy, (C.
sub.
1 -C.
sub.
4 alkoxy)methoxy, (C.
sub.
2 -C.
sub.
8 acyloxy)methoxy or together with R.
sup.
1 represents --OCH(C.
sub.
1 -C.
sub.
8 alkyl)--O(CH.
sub.
2).
sub.
1-2 --, --OCH(C.
sub.
6 -C.
sub.
14 aryl)--O--(CH.
sub.
2 ).
sub.
1-2 --, --OCH(C.
sub.
1 -C.
sub.
8 alkyl)-- or --OCH(C.
sub.
6 -C.
sub.
14 aryl), T represents --O--, --S--, --SO.
sub.
2 --, --CH.
sub.
2 -- or --CH.
dbd.
CH--, R.
sup.
1, if n is 1 and X is --OR.
sup.
6, represents C.
sub.
1 -C.
sub.
8 alkyl which can be substituted by C.
sub.
2 -C.
sub.
8 acyloxy, --COO--(C.
sub.
1 -C.
sub.
4) alkyl or --CN, or represents C.
sub.
5 -C.
sub.
6 cycloalkyl or C.
sub.
7 -C.
sub.
9 phenylalkyl, and, in all other cases, represents alkyl of 1 to 8 carbon atoms which can be substituted by OH, C.
sub.
1 -C.
sub.
4 alkoxy, C.
sub.
2 -C.
sub.
8 acyloxy, --COO--(C.
sub.
1 -C.
sub.
4)alkyl or --CN, or represents cycloalkyl of 5 to 6 carbon atoms or phenylalkyl of 7 to 9 carbon atoms, R.
sup.
2 has one of the meanings assigned to R.
sup.
1 or represents allyl, methallyl, 2-carbamoylethyl, 2-(N-C.
sub.
1 -C.
sub.
4 alkylcarbamoyl)ethyl, 2-(N,N-di-C.
sub.
1 -C.
sub.
4 alkylcarbamoyl)ethyl, 2-(2-pyridyl)ethyl, 2-(2-oxo-1-pyrrolidinyl)ethyl or 2-(di-O-C.
sub.
1 -C.
sub.
4 alkylphosphono)ethyl, or R