GB1172935A - Heat-Developable Diazotype Material - Google Patents

Abstract

1,172,935. Diazotype materials. KALLE A.G. March 17, 1967 [March 19, 1966], No.12724/67. Heading G2C. A heat-developable diazo-type material comprises a support, a light-sensitive layer containing at least one diazo compound and an acid, a heatsensitive layer containing at least one #-aminodicarboxylic acid, or monometal salt thereof, of formula: (in which R 1 is OH, or an optionally substituted alkyl, alkenyl, cycloalkyl, aralkyl or phenacyl group, and R 2 and R 3 are each optionally substituted alkyl, alenyl, cycloalkyl or aralkyl groups or H, or together form an optionally substituted heterocyclic ring), and optionally one or more intermediate layers, one layer in the material containing a colour coupler. In embodiments the coupler may be in the diazo or heat-sensitive layer, the diazo and heat-sensitive layers may be positioned on the opposite sides of a gaspermeable support, optionally with a layer containing an ammonium salt and SiO 2 in a binder underlying the heat-sensitive support so that the amine formed on heating the amino-acid is converted to ammonia which effects a more rapid development; alternatively the diazo and heatsensitive layers are coated on the same side of the support, optionally with a gas-permeable resin or wax layer between them. The support is preferably paper, optionally subbed with SiO 2 in aqueous casein or polyvinyl acetate. The diazo compound may be a zinc chloride double salt of 4-(N-ethyl-N- -hydroxyethyl) amino benzene diazonium chloride, 4-N,N-diethylamino-benzene diazonium chloride or 4-morpholino-2, 5-diethoxybenzene diazonium chloride, preferably in a cellulosic or polyvinylacetate binder, optionally containing an Alizarin dye. Specified couplers are 2, 3-dihydroxynaphthalene-6-sulphonic acid sodium salt, 1-[2<SP>1</SP>-N, N-diethylamino carbanilido] -3, 5-dihydroxy-4-bromo-benzene and a mixture of phloroglucinol carboxylic acid and y-resorcylic acid. The heat-sensitive acid is preferably dispersed in a resin binder in the form of the free acid, and is optionally admixed with SiO 2 , ZnO, CaCO 3 , talcum or NaHCO 3 , or an alkali, alkalineearth, Zn or Al salt. The diazo material may also be developed by ammonia, or used in a thermographic process by contacting it with an original having heat absorbing areas, exposing it imagewise with infrared irradiation and uniformly exposing it with light to decompose the unreacted diazo compound.