Multifunctional cationic photoinitiators, their preparation and use

摘要

Compounds of formula (I): [where: R¹ is a direct bond, oxygen, a group >CH₂, sulphur, a group >C-O, a group-(CH₂)₂- or a group-N-R^a, where R^a is hydrogen or alkyl; R³, R⁴, R⁵ and R⁶ are hydrogen or substituentsalpha; R⁸, R⁹, R¹⁰ and R¹¹ are hydrogen, hydroxy or alkyl; or R⁹ and R¹¹ are joined to form a fused ring system with the benzene rings to which they are attached; R⁷ is a direct bond, oxygen or a -CH₂-group; p is 0 or 1 ; substituentsalpha are: alkyl, alkoxy, alkenyl, halogen, nitrile, hydroxyl, aryl, aralkyl, aryloxy, aralkyloxy, arylalkenyl, cycloalkyl, carboxy, carboxyalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkylcarbonyloxy, alkanesulphonyl, arenesulphonyl, alkanoyl or arylcarbonyl; n is 1 to 12; R¹² is hydrogen, methyl or ethyl; A is a group -[O(CHR¹³CHR¹⁴)_a]_y-, -[O(CH₂)_bCO]_y-, or -[O(CH₂)_bCO](_y-1)-[O(CHR¹³CHR¹⁴)_a]-, where: one of R¹³ and R¹⁴ is hydrogen and the other is hydrogen, methyl or ethyl; a is 1 to 2 ; b is 4 to 5 ; Q is a residue of a polyhydroxy compound having from 2 to 6 hydroxy groups; x is a number greater than 1 but no greater than the number of available hydroxyl groups in Q; y is a number from 1 to 10; 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.