GB1474943A - Photo-sensitive composition for dry formation of image - Google Patents

Abstract

1474943 Photo-sensitive composition NIPPON PAINT CO Ltd 28 May 1974 [25 May 1973 11 Oct 1973] 23686/74 Heading G2C A photo-sensitive composition for the dry formation of images comprises, in the absence of a polymerizable compound having an olefinic double bond, a dyestuff having a photo-fading property, an aryl ketone compound as sensitizing agent and a high molecular polymer as binder which is compatible with the dyestuff and the sensitizing agent and selected from a polymer containing an N-C bond wherein the carbon atom bears one or more hydrogen atoms, a polymer containing a secondary OH group and a polymer containing a benzene ring bearing at least one of methyl, methylene and methene. Azo, azomethine, triphenylmethane, xanthene, oxazine, naphthol, anthraquinone and cyanine dyestuffs are specified. The aryl ketone compound may be a benzo-phenone, an acetophenone, a benzoin, an acyloin or an α-diketone. The polymer may be a polyamide resin, a urea resin, a urethane resin, a melamine resin, an N-substituted high polymer having acrylamide and/or methacrylamide units, a vinyl acetate polymer or a partially saponified derivative thereof, a polymer of a vinyl monomer having a secondary hydroxyl group, an epoxy resin, a cellulose resin, a butyral resin, an acetal resin, an acrylic resin, an alkyd resin, an unsaturated polyester resin, a copolymer of styrene or a derivative thereof and/or a phenol resin. The sensitivity can be increased by adding aldehydes, amides or thiocarbonyl compounds. The photofading is prevented by the presence of oxygen or air. It is promoted by strong light but not by scattered light in a room. The visible image can be stored in air without fixing. It is eliminated by irradiation with light of the whole surface or by dipping into weak acid. The compositions can be applied to transparent supports to give materials for the preparation of colour proofs from colour separation negatives. The colour image sheets can then be combined by the over-lay or transfer methods.