GB1002212A - Improvements relating to photo-polymerization initiators - Google Patents

Abstract

Polymeric compounds comprise a plurality of recurring glucose units or units derived from glucose, to which are joined, by ester, ether, amide or urethane links, one or more polynuclear quinone radicals. The glucose polymer may be cellulose or a cellulose derivative, and the quinone radical may be an anthraquinone radical. The polymeric compounds may be formed by esterifying a cellulose partial ether or ester with a polynuclear quinone containing an acid halide group. Cellulose acetate, propionate, butyrate, phthalate, maleate, succinate, glutarate, acetate-phthalate, acetate-succinate, propionate-maleate, acetate-butyrate, or methyl, ethyl or benzyl cellulose may be esterified with anthraquinone-1-carboxylic acid chloride, anthraquinone -2-carboxylic acid chloride, anthraquinone-2-sulphonic acid chloride, 1-nitroanthraquinone - 4 - sulphonic acid chloride, 1,4-dichloro - anthraquinone - 2 - sulphonic acid chloride, or 1-nitroanthraquinone-8-sulphonic acid chloride. The polymeric compounds may also be formed by reacting a cellulose derivative containing free carboxyl groups with a polynuclear quinone containing a free amino group, thus forming an amide link. Thus, cellulose acetate hydrogen succinate, maleate, glutarate or phthalate, or carboxymethyl cellulose may be reacted with 1-amino anthraquinone or 2-amino anthraquinone. The polymeric compounds may be used in photopolymerizable composition to initiate the photopolymerization of ethylenically unsaturated compounds containing at least one terminal ethylenic group and capable of forming a high polymer by photo-initiated addition polymerization. Such unsaturated compounds preferably have a boiling point above 100 DEG C. and a molecular weight less than 1500. The unsaturated compound may be an alpha-methylene carboxylic acid ester of a polyol, an amine derived from an alphamethylene carboxylic acid, a vinyl ester, styrene or a derivative thereof, or an unsaturated aldehyde. Many such compounds are specified. The ethylenic unsaturation may also be present in the composition as an extra-linear substituent attached to a thermoplastic linear polymer, e.g. polyvinyl acetate/acrylate, cellulose acetate/acrylate, cellulose acetate/methacrylate, N - acrylyloxymethylpolyamide, N - methylacrylyloxymethylpolyamide or allyloxymethylpolyamide. The photopolymerizable composition may also contain a separate thermoplastic polymer, fillers or reinforcing agents which form substantially transparent compositions, e.g. organophilic silicas, bentonites, or powdered glass, organic dyestuffs, and pigments, e.g. titanium dioxide, carbon, graphite, ceramics, clays, phosphor particles or aluminium, magnetic iron or copper particles. The compositions, which are substantially stable below 185 DEG C. may be used in the photopolymerizable layer or layers of photopolymerizable elements for the preparation of printing reliefs and for thermal image transfer processes (see Division G2-G3). Such photopolymerizable elements may comprise a support carrying one layer of the photopolymerizable composition, or two or more layers of photopolymerizable compositions containing differing contents of the polymeric photo-initiator of the invention (see Division B5-B6). Examples describe the amidation of cellulose acetate hydrogen succinate by 2-aminoanthraquinone, the esterification of cellulose acetate hydrogen succinate by anthraquinone-2-carboxylic acid chloride and the esterification of cellulose acetate by 2-anthraquinone sulphonyl chloride and by phenanthrenequinone-3-carboxylic acid. These compounds are formulated into photopolymerizable compositions using triethylene glycol diacrylate or pentacrythritol triacrylate as the ethylenically unsaturated component. Specifications 741,294, 843,238, 864,041, 905,070, 905,700, 935,627 and 945,807 are referred to.