GB539314A - Improvements in or relating to layers sensitised by means of a diazonium compound and method of preparing such layers - Google Patents

Abstract

539,314. Photographic diazotype processes. PHILIPS LAMPS, Ltd. April 8, 1940, No. 6347. Convention date, April 11, 1939. [Class 98 (ii)] A light-sensitive layer is produced on a support, preferably water-impermeable, by suspending a diazonium compound in a solution of water-insoluble binder in a volatile organic liquid, in which is preferably also suspended a coupling component, and applying the dispersion to the support and evaporating the organic liquid. The material to be suspended and the organic liquid may be ground together in a ball mill. In an example, an aluminium plate is coated with a suspension of the zinc chloride double salt of p-diethylaminobenzenediazonium chloride and phloroglucinol in a solution of cellodammar resin in carbon tetrachloride, the solvent is partly evaporated at 80 ‹C. the excess suspension is poured off, and the solvent completely evaporated. After exposure, development may be effected with gaseous or aqueous ammonia. The surface may be sprayed with a 5 per cent. solution of cellodammar resin in carbon tetrachloride. A suspension of the cadmium and zinc chloride double salts of p-benzylethylaminobenzenediazoniun chloride may also be used. Acids such as tartaric or oxalic may be added to prevent premature coupling. In a further example, an aluminium plate is coated with a suspension of the cadmium and zinc chloride double salts of p-benzylethylaminobenzenediazonium chloride in a solution of cellodammar resin in trichlorethylene. After exposure, development is effected with an aqueous ammonia solution of phloroglucinol. The coupling component, for example #-naphthol, may be dissolved in the organic liquid, for example benzene. The finished images may be protected by a layer of celluloid lacquer. Other supports referred to are metals other than aluminium, glass, cellulose acetate, rubber, rubber-derivatives, and paper. Other binding agents referred to are polymerized hydrocarbons such as polystyrene, polymerized unsaturated fatty acid esters such as derivatives of acrylic acid and its homologues, vinylacetic acid, and resins and gums such as ester gum, mastic, and colophony. Toluene is also referred to as a volatile organic solvent. Specification 524,786 is referred to.