Photopolymerizable composition containing photoinitiators having at

Abstract

A photopolymerizable composition comprises an addition polymerizable compound having at least one ethylenically unsaturated double bond and a photopolymerization initiator, wherein it comprises a compound represented by the following general formula (I) as the photopolymerization initiator: ##STR1## (wherein R.sub.1 and R.sub.2 may be the same or different and each independently represents a substituted or unsubstituted alkyl, aryl or alkenyl group or R.sub.1 and R.sub.2 may form a non-metallic ring together with the sulfur atoms to which they are bonded; n is 0, 1 or 2; G.sub.1 and G.sub.2 may be the same or different and each represents a hydrogen atom, a cyano group or a substituted or unsubstituted alkoxycarbonyl, aryloxycarbonyl, acyl, arylcarbonyl, alkylthio, arylthio, alkylsulfonyl, arylsulfonyl or fluoroalkylsulfonyl group, provided that G.sub.1 and G.sub.2 do not simultaneously represent hydrogen atoms or G.sub.1 and G.sub.2 may form a non-metallic ring together with the carbon atom to which they are bonded). The photopolymerizable composition is improved in the sensitivity to the light rays having strong emission spectra at the long wavelength range and can be used in making, for instance, paints, printing inks and printing materials such as letterpress and lithographic printing materials.