GB560451A - Manufacture of azo-dyestuffs - Google Patents

Abstract

Trisazo dyes, suitable for dyeing or printing animal fibres, e.g. wool, silk or leather, or cellulose fibres, e.g. cotton, linen, ramie, hemp or regenerated cellulose, the after-coppered dyeings being specially fast to light, to washing and to acid, are obtained by coupling (alkaline) a diazotised 4-chloro-2-aminophenol, free from sulphonic acid groups and carrying a nitro group in the 5- or 6-position, with an azo dyestuff of the general formula <FORM:0560451/IV/1> wherein R1 represents a residue of the benzene series, which may be substituted, e.g. by methyl, and carries the OH and COOH groups in o-position to each other and R2 represents a 4 : 41-diphenyl residue, which may be substituted, e.g. by halogen or by alkyl or alkoxy groups but is free from sulphonic acid groups. The products may be treated in substance, in the dyebath or on the fibre with an agent yielding metal, e.g. copper. In an example the preparation is described of the dyestuffs, salicylic acid\sMbenzidine-->(acid 2 : 5 : 7-acid (alkaline)\sM4-chloro -5- or 6-nitro-2-aminophenol. An example is also given of the dyeing process for cotton with after-coppering in the dyebath. Specifications 12932/15, 101,601, [both in Class 2 (iii)], 455,274, 468,362 and 516,076 are referred to. The Specification as open to inspection under Sect. 91 comprises also (a) the use as diazo component of any amine of the benzene series, free from sulphonic acid groups and containing a lake-forming group, e.g. a hydroxy, carboxy or carboxymethoxy group, in o-position to the diazotised amino group and at least one halogen atom, (b) the use of any substituted benzidine component. This subject-matter does not appear in the Specification as accepted.