Patent ID: 8598249

Claim:
Photoinitiators of the formula (I) (PI-Sp) n -BB (I) wherein PI is a thioxanthone moiety optionally comprising additional substituents further to the Sp moiety Sp is a spacer unit which is selected from the group consisting of BB is a backbone moiety selected from the group consisting of wherein R 2 and R 3 are the same or different and denote H, an optionally substituted linear or branched C 1-8 alkyl residue or an acyl residue; R 4 is H or Hydroxy R 5 is H or C 1-4 -Alkyl; R 6 and R 7 are the same or different and denote H or an optionally substituted linear or branched C 1-8 alkyl residue; A is NR 8 , wherein R 8 is H, an optionally substituted linear or branched C 1-8 alkyl residue, or an optionally substituted C 1-8 alkylamine residue; R 9 is H or C 1-4 -Alkyl; p is an integer from 1 to 10, preferably from 3 to 6; q is an integer from 3 to 12; r is in the range from 2 to 3; w is an integer from 2 to 15, preferably from 3 to 10; and n is 1 or 2.