PURPOSE: To obtain a sulfonium salt useful as a photopolymerization initiator used for obtaining an actinic-radiation-curing composition which can give a lowly odorous cured product and is excellent in compatibility, storage stability and curability by selecting a specified sulfonium salt.
CONSTITUTION: This initiator comprises a sulfonium salt represented by formula I {wherein X is a group of formula II [wherein R6 to R15 are each H, halogeno, nitro, alkoxy, a 1-20C aliphatic group which may have OH, an ether group, an ester group, (meth)acryloyl, epoxy or allyl in the structure, phenyl or (thio) phenoxy group]; R1 to R5 are each H, a 1-15C aliphatic group, nitro, alkoxy, phenyl or a group of formula III; n is 1-4; and Z is a compound of the formula: MQp or MQp-1 (wherein M is P, B, As or Sb; Q is halogeno; and p is 4-6)}.
YOSHIOKA RITSUKO
ISHII KAZUHIKO
YOKOSHIMA MINORU
