Water developable photopolymerizable compositions containing phosphine

Abstract

A photopolymerizable composition and photosensitive elements produced therefrom are disclosed. The photopolymerizable composition includes: (a) a monomer component, (b) a polymer component, (c) a photopolymerization initiator, and (d) an activator. The monomer component contains at least one water soluble, monofunctional unsaturated ethylenic monomer or the combination of such a monomer and at least one polyfunctional unsaturated ethylenic monomer. The polymer component includes a partially saponified water soluble, polyvinyl acetate polymer compatible with the monomer components. The polyvinyl acetate polymer contains both acetyl and hydroxyl groups and has a polymerization degree of from 300-2000. The degree of saponification of the polymer is desirably in the range of 65 to 99 percent. The preferred photopolymerization initiators are acetophenone derivatives such as 2,2-dimethoxy-2-phenyl acetophenone, 2,2-diethoxy-2-phenyl acetophenone, 2,-2-diisopropoxy-2-phenyl acetophenone, benzoin alkyl, aryl, allyl or vinyl ethers, or benzophenone derivatives such as benzophenone, 2-methylbenzophenone, 2-methoxybenzophenone or 2,2'-dimethoxybenzophenone, which are compatible with the monomer component and the polyvinyl acetate polymer and are activatable by actinic light. Finally, the activator is a phosphine derivative generally described by the formula: ##STR1## wherein any of X, Y and Z are hydrogen, halogen, alkyl, alkoxy, aryl, vinyl, or allyl, although not more than one or X, Y and Z may be hydrogen. It is especially preferred in the practice of the present invention that at least one of X, Y and Z in the phosphine derivative activator component be an aryl group.