GB450817A - Improvements in and relating to diazo type printing processes - Google Patents

Abstract

450,817. Photographic diazotype processes. HALDEN & CO., Ltd., J., and HOLDEN, J., Rowsley Works, Reddish, near Stockport. May 2, 1935, No. 2462 /36. Divided out of 443,955. [Class 98 (ii)] Diazotype printing-papers are dusted or coated with a finely powdered agent which is rubbed under pressure to form a film on the sensitive surface as distinct from a layer of powder, the surface being given a sheen or polish and being capable of holding other agents applied to the surface. Substances which form such a film are alkaline salts of the fatty acids, e.g. dry soaps, Pulv. Sapo. Durus B.P. ; Pulv. Sapo Animalis B.P. ; Pulv. coconut oil soap; and finely powdered waxy substances, e.g. carnauba wax, stearic acid. After application of the powder, the surface is rubbed under pressure as by a felt-covered weight and the excess powder removed, e.g. by fast rotating brushes. Coupling accelerating agents such as inorganic carbonates or oxides and coupling agents, e.g. arylide of 2 : 3 oxynaphthoic acid may be included in the dusting powder. The powdered soaps themselves act also as coupling accelerating agents. Stabilizing agents such as stearic, palmitic, &c. acids containing 10 per cent paraffin wax may be applied to the treated paper, and waterproofing agents as described in Specification 418,976 and 425,030, oil proofing agents as described in Specification 424,976, insecticides such as chloro - naphthalene derivatives.. background tinting agents such as leuco esters or vat dyestuffs, and translucing agents as described in Specification 425,215, [Group VIII], may also be applied individually or successively to the paper. Five examples are described in which the diazo compound of p-aminodiphenylamine or the diazo compound of 4-1<1> methylphenoxyacetylamino - 2 : 5-dimethoxy-l-aminobenzene, with oxalic or tartaric acid are employed as light-sensitive agents.