| abstract |
The invention provides thioxanthone derivatives of general formula <IMAGE> (I) wherein one of R2, R3 and R4 is a group of formula <IMAGE> (II) in which one of R5, R6 and R7 is an alkyl or a benzyl group, the others being alkyl groups and A- represents an anion, and R1 and the others of R2, R3, and R4 are independently selected from hydrogen atoms, alkyl groups and alkoxy groups; and the use of such derivatives as photoinitiators, particularly in aqueous photopolymerizable compositions for the production of stencils for screen printing. |