GB334874A - Improvements in rosin soap lakes of azo compounds - Google Patents

Abstract

334,874. Marks, Sir G. C., (Du Pont de Nemours & Co., E., I.). March 8, 1929. Lakes.-Oil and water-insoluble lakes of azodyestuffs are prepared by incorporating a metallic compound in a mixture of an azo dye of acidic character and a resin soap in aqueous medium, to form a precipitate of the metallic compounds of resinate and azo-dye in which the resinate is present in amounts of from about 5-60 per cent of the finished product. Or the metallic resinate is incorporated with the precipitated pigment of the azo-dye of acidic character prior to the development of the pigment and the latter is then developed by boiling. The azo-dye may be soluble, slightly soluble or substantially insoluble in water and usually contains sulphonic acid and/or carboxylic acid groups. The resin soap may be incorporated wholly or in part, prior to or during the coupling of the azo-dye components and in the case of a water soluble dye substantially simultaneous precipitation of the metallic compounds of resinate and azo-dye may take place. The metallic salt is preferably an alkaline earth metal compound such as calcium chloride, barium chloride, or mixture thereof, or a salt or salts of magnesium, lead or copper may be used. In examples (1) 2-naphthylamine-1-sulphonic acid is diazotized and coupled with #- naphthol, and to the alkaline solution is added a solution of sodium resinate and the mixture precipitated with barium chloride or calcium chloride and boiled; an example also illustrates the precipitation with calcium chloride at the boil; (2) a solution of sodium resinate is added to 2 : 3-oxynaphthoic acid and a diazotized solution of p-toluidine-m-sulplionic acid run in; the mixture is precipitated with calcium chloride and boiled; (3) 2-naphthylamine-1-sulphonic acid is diazotized and coupled with 2 : 3-oxynaphthoic acid m-nitranilide, a solution of sodium resinate added, and the mixture precipitated with barium chloride ' and boiled; (4) diazotized alpha-naphthylamine is added to a solution of 1-naphthol-5-sulphonic and sodium resinate, the mixture precipitated with calcium chloride, and boiled.