| abstract |
Thioxanthonecarboxylic acid esters, thioesters or amides of the formula I <IMAGE> (I) in which X and Z are hydrogen or one of the substituents defined in more detail in claim 1 and Y is -OR1, -SR1 or -N(R1)(R2), in which R1 is C1-24alkyl and R2 is H or R1, are suitable, if desired together with amines, as initiators for the photopolymerization of ethylenically unsaturated compounds or for photochemical crosslinking of polyolefines. They are also used an sensitizers for photocrosslinkable polymers. They can be prepared by methods known per se, for example by cyclization of phenylthio-phthalic, -isophthalic or -terephthalic acids, which can be correspondingly substituted, and subsequent reaction with suitable alcohols, thiols or amines. |