Sulfonium salt photoinitiators and methods of led curing a composition with said sulfonium salt photoinitiators

A method of curing a composition comprising a cationically-polymerizable compound and a photoinitiator of formula (I):

• wherein:
• Y is an anion, the valency of which is y,
• either R12 and R13 are linked with each other so that the
• group represents
• wherein
• R16, R17, R18 and R19 are independently chosen among H, a halogen, a (C1-C6) linear or branched alkyl group, a (C1-C6) linear or branched alkoxy group, a —O—(CH2)i—COOR28 or —(CH2)i—CH—(COOR28)2 group wherein i is 1 or 2 and R28 is H or a (C1-C4) linear or branched alkyl group, and
• R11, R14 and R15 are independently H, a halogen, a (C1-C6) linear or branched alkyl group, a (C1-C6) linear or branched alkoxy group and —S-Ph-C(═O)-Ph
• or R12 and R13 are not linked with each other, and
• R11, R12 and R13 are independently chosen from H, a halogen, a (C1-C6) linear or branched alkyl group, a (C1-C6) linear or branched alkoxy group, a pyrrolidin-1-yl, a -L-Ph1 group wherein L is a single bond, CH2 or O and Ph1 is a phenyl group optionally substituted by one or several substituents chosen from a halogen, a (C1-C6) linear or branched alkyl group and a (C1-C6) linear or branched alkoxy group, provided that at least one R11, R12 and R13 is a -L-Ph1 group, and
• R14 and R15 are independently H, a halogen, a (C1-C6) linear or branched alkyl group, a (C1-C6) linear or branched alkoxy group and —S-Ph-C(═O)-Ph,
• R3 is chosen from, H, a halogen, a (C1-C6) linear or branched alkyl group, a (C1-C6) linear or branched alkoxy group, a —O—(CH2)l—COOR31 group and a —(CH2)l—CH—(COOR31)2 group, wherein l is 1 or 2 and R31 is H or a (C1-C4) linear or branched alkyl group,
• R2, R4, R5, R7, R8, R9 and R10 are independently chosen from H, a halogen, a (C1-C6) linear or branched alkyl group, a (C1-C6) linear or branched alkoxy group and a —O—(CH2)m—COOR32 or —(CH2)m—CH—(COOR32)2 group wherein m is 1 or 2 and R32 is H or a (C1-C4) linear or branched alkyl group,
• the method comprising irradiating the composition with at least one light source having a maximum output wavelength in the range of 350 to 460 nm.