| abstract |
The invention relates to a process for preparing organosilicon group containing photoinitiators of the formula (I), wherein m is a number from 1 to 200; q is 0 or 1; A is IN-C(O)-O-CHR3-Y- or IN-C(O)-NH-CHR3-Y-; A’ is A or R1’; R1 and R1’, R2 and R2’ are C1-C18alkyl or phenyl, or -(O)q-SiR1R1’R2; R3 is hydrogen or C1-C6alkyl, Y is a divalent group selected from C1-C10alkeylene, C2-C10alkenylene or -(CH2)b-O-(CH2)a-; and b are each independently of the other a number of 1 to 6; IN is a photolabile functional moiety of the formula (II) or (III), wherein R4 is hydrogen or -C(O)-C(O)-OH or -C(O)-C(O)-OC1-C6alkyl and n is 1-3; R5 and R6 are C1-C12alkyl or together are cycloC5-C7alkyl; R7 is hydroxy, C1-C6alkoxy or morpholinyl; X is -(CH2)a-, -(CH2)b-O-(CH2)a- or -(CH2)b-O-CO-(CH2)a-; a and b are each independently of the other a number of 1 to 6; whereby the process is characterized in that a photolabile functional moiety containing a carboxy group (IN-COOH) or an alkoxycarbonyl group (IN-CO-OC1-C6alkyl) is reacted with a carbinol- or amino terminated organosilicon compound of the formula (IV), wherein m, R1 and R1’, R2 and R2’ are as defined above and B is -Y-CHR3-OH or -Y-CHR3-NH2; B’ is B or R1’, in the presence of an enzyme which catalyzes the esterification, transesterification or amidation reaction. |