GB343016A - Manufacture of azo-dyestuffs and the application thereof - Google Patents

Abstract

The dyestuffs made by coupling an ester of 1-naphthol-4-carboxylic acid with a diazo compound or metal compounds of these dyestuffs are used for colouring cellulose varnishes. In an example the dyestuff from the ethyl-ester and diazotized aniline is dissolved in finished nitrocellulose varnish; the product yields transparent orange coatings fast to light. By incorporating suitable additions, the varnish may be converted into a mat varnish or covering varnish.ALSO:Azo dyes are made by coupling a 1-naphthol-4-carboxylic acid ester with a diazo compound. They may be used as acid, mordant, lake and cotton dyestuffs or for cellulose derivatives, e.g. acetate silk or nitrocellulose varnishes and yield metal compounds by treatment with agents yielding metal, e.g. copper and chromium compounds. In examples (1) the methyl or ethyl ester is coupled with diazotized aniline, monoacetyl-p-phenylene diamine, m-aminobenzylalcohol, sulphanilic acid and 2-naphthylamine-1-sulphonic acid (red barium lake), (2) the dyestuff 4-chloro-2-aminophenol-6 - sulphonic acid --> 1 : 4 - naphtholcarboxylic methylester is treated with agents yielding copper or chromium, (3) the dyestuff 1-amino-2-naphthol-4 - sulphonic acid --> the methylester yields reddish-blue shades on wool when after-chromed, (4) the dyestuff aniline --> the ethylester is dissolved in finished nitrocellulose varnish; the product yields transparent orange coatings; the metal compounds as in (2) may also be used, (5) acetate silk is dyed red orange with the dyestuff aniline --> the methylester. Specifications 263,579 and 271,898, [both in Class 2 (iii), Dyes &c.], are referred to.