GB445266A - Process for the improvement of dyeings on cellulosic fibres with substantive dyestuffs - Google Patents

Abstract

Azo dyes, forming on the material; printing.--Dyeing on cellulosic fibres with azo dyestuffs of the general formula R[--NH--CO--R<1>--N = N--Py]n wherein R represents the residue of an aromatic amine or of an aminoazo compound not containing the residue Py, R<1> represents a residue of the benzene series, Py represents the residue of a 1-aminoaryl - 5 - pyrazolone - 3 - carboxylic acid (or ester) coupling component, and n is 1 or 2, the whole dyestuff being so constituted that only the aminoarylpyrazolone residue is capable of further coupling with a diazo component, are after-treated with a diazotized base free from water-solubilizing groups, e.g. diazotized m- or p-nitraniline or 4- or 5-nitro-2-anisidine, to improve the fastness to washing. Compared with the dyeings similarly produced from the dyestuffs specifically referred to in Specifications 14315/09 and 7303/13, [both in Class 2(iii)] the resulting dyeings are of an improved dischargeability to a pure white. The following examples are specified: (1) Cotton, dyed from a Glauber's salt-soda bath with the reduced dyestuff from tetrazotized di - (4<11> - aminobenzoyl) - 4 : 4<1> - diaminodiphenylurea - 3 : 3<1> - disulphonic acid (1 mol.) and 1-(3<1>-nitro)phenyl-5-pyrazolone-3-carboxylic acid (2 mols.), is after-treated with diazotized p-nitraniline to obtain a dyeing of good fastness to light and dischargeable to a pure white. (2) Cotton, similarly dyed with the dyestuff obtainable by reducing the nitro group of p-nitrobenzoyl-p-phenylene diamine --> 1-phenyl-5-pyrazolone-3-carboxylic acid, diazotizing, coupling with 1 - (m-nitro)phenyl - 5 - pyrazolone - 3 - carboxylic acid and reducing the nitro group, is after-treated with diazotized p-nitraniline. (3) Cotton, similarly dyed with the dyestuff obtainable by saponifying the acetylamino group of acetyl - p - phenylenediamine --> salicylic acid, condensing with p-nitrobenzoyl chloride, reducing the nitro group, diazotizing and coupling with 1 - (m - or p - amino)phenyl - 5 - pyrazolone - 3 - carboxylic acid, is after-treated with diazotized p-nitraniline or 4- or 5-nitro-2-anisidine. (4) Cotton, similarly dyed with the dyestuff, 2-aminobenzoic acid --> (alkaline) p - aminobenzoyl - 2 - amino - 5 - naphthol - 7 - sulphonic acid --> 1-(m-amino)phenyl-5-pyrazolone-3-carboxylic acid, is after-treated with diazotized p-nitraniline. (5) Cotton, similarly dyed with the dyestuff, m-aminobenzoyldehydrothiotoluidinesulphonic acid --> 1-(m-amino)phenyl - 5 - pyrazolone - 3 - carboxylic acid, is similarly after-treated.