GB719920A - Photosensitive vesicular print material and process of making same - Google Patents

Abstract

719,920. Photosensitive vesicular diazotype print material. GENERAL ANILINE & FILM CORPORATION. Dec. 11, 1952 [Dec. 12, 1951], No. 31410/52. Class 98(2) A solution of 5 to 1 parts of a thermoplastic hydrophobic resin such as polyvinyl acetate or polymethylmethacrylate or of a cellulose ester such as the acetate or nitrate, and 1 to 6 parts of a resinous copolymer made from a vinyl compound such as methyl-, isobutyl-, 2-methoxy-ethyl- or 2-ethoxy-ethyl-vinyl ether and maleic anhydride or this when substituted by a lower alkyl group, is coated on a support and dried to give a clear layer, and the layer is treated with a moist water soluble nitrogenous base, usually aqueous ammonia vapour, to make the copolymer hydrophilic. and then photosensitized by application of an aqueous solution of a stabilized diazo compound and, finally, dried. Irradiation of the material with actinic light through a design and then subjection to an elevated temperature develops an image and reduces the water sensitivity of the layer. If desired the print may be re-exposed to light to destroy remaining diazo compound. Clean whites with soft tone gradation result. In Example 1 specified proportions of cellulose acetate and a vinyl methyl ether-maleic anhydride capolymer, with polyvinyl methyl ether as plasticizer, dissolved in a mixture of ethylene glycol monomethyl ether and acetone are coated on black paper, dried, and the material is passed through ammonia vapour several times at 180‹F., washed with dilute HC1. dried at 50‹C., sensitized by immersion in an aqueous ethanol-ethylene glycol solution of N,N-diethylaniline -4-diazonium chloride zinc chloride double salt acidified with citric acid, and again dried. On exposure through a positive transparency to ultraviolet rays and development by sudden application of heat, as by use of a rotary ironing mangle at 347‹F. a stable image with soft gradation and good moisture resistance results. Exposure to direct actinic light destroys the remaining diazo compound without adversely affecting the prints. Nine further examples specify further copolymer coating formulations for use by the procedure of Example 1. If a transparent support as of glass or regenerated cellulose is used a negative print results.