Abstract: An intaglio printing ink, curing by free radical acrylate chemistry, which does not fluoresce in at least the visible region under ultraviolet light is prepared by using an acylphosphine oxide as the photoinitiator.

Abstract: Polyfunctional cyclic carbonates provide a useful additional monomer for energy-initiated cationic copolymerisation with such other monomers and oligomers as epoxides and oxetanes.

Abstract: In a cationically curable composition comprising an epoxide, a cationic photoinitiator and a cyclic carbonate, we have found that the use of higher levels of cyclic carbonate than have been used hitherto can lead to much enhanced cure speed and post-cure.

Abstract: A coating composition for cationic curing comprises an epoxide, a multi-functional oxetane, a cationic photoinitiator and a cyclic carbonate at a higher level than has been used conventionally. This appears to have a synergistic effect, improving cure speed and post-cure.

Abstract: A sprayable energy-curable coating composition comprises an epoxide monomer or oligomer, a cationic photoinitiator and a cyclic carbonate, the cyclic carbonate being present in an amount of at least 7% by weight of the entire composition.

Abstract: Photoinitiator compounds of formula (I): {where: A represents a direct bond or a group of formula —[O(CHR7CHR6)a]y—, —[O(CH2)bCO]y—, or —[O(CH2)bCO](y-1)—[O(CHR7CHR6)a]—, where one of R6 and R7 is hydrogen and the other is hydrogen or methyl; a is a number from 1 to 2; b is a number from 4 to 5; Q is a residue of a polyhydroxy compound having 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; R1, R2, R3 and R4 are individually the same or different and each is hydrogen, hydroxy, or alkyl; or R1 and R3 are joined to form a fused ring system with the benzene rings to which they are attached; and R5 represents a direct bond, an oxygen atom or a methylene group} 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.