| abstract |
Compounds of formula (I) [in which: R1 represents a direct bond, an oxygen atom, a group >CH2, a sulphur atom, a group >C=O, a group -(CH2)2- or a group of formula -N-Ra, where Ra is hydrogen or an alkyl; R4, R5, R6 and R7 are each hydrogen or various groups or atoms; R8, R9, R10 and R11 are each hydrogen, hydroxy, or alkyl; or R9 and R11 form a fused ring system with the benzene rings to which they are attached; R12 is a direct bond, oxygen atom or methylene; and X is an anion; and esters thereof] are useful as cationic photoinitiators, especially for use in surface coating applications, such as printing inks and varnishes, and which are intended to be cured by polymerisation initiated by radiation. |