GB429025A - Process for producing azo-dyestuffs on the fibre - Google Patents

Abstract

Azo dyes, forming on the material; printing.--Azo dyes are produced on vegetable fibres by impregnating them with an arylide of 2 : 3-oxynaphthoic acid, treating the impregnated fibres with a neutral or approximately neutral solution of diazotized 4-aminodiphenylamine or a substitution product thereof, and passing them through water at raised temperature. The diazo solution preferably contains an agent capable of binding alkali such as magnesium sulphate, sodium bicarbonate or zinc sulphate. White resist effects on a coloured ground are obtainable by printing with an acid salt prior to the treatment with the diazo solution. The following examples are specified. (1) Cotton piece goods are impregnated with a solution containing the 3<1>-nitranilide of 2 : 3-oxynaphthoic acid, caustic soda and turkey red oil, dried, passed through a solution containing the diazonium chloride of 4-amino-3-methoxydiphenylamine and magnesium sulphate, pressed, passed through water at 50--80 DEG C. and soaped at the boil to obtain a vivid blue dyeing. (2) Piece goods, impregnated and dried as in (1), are printed with an aqueous paste containing aluminium sulphate and neutral starch-tragacanth thickening, dried, developed as in (1) and passed through a solution of sodium bisulphite, which removes the excess of diazo component, to obtain white resist effects on a blue ground. Specifications 331,056, [Class 15 (ii)], and 404,304 (as open to inspection under Sect. 91) are referred to. The Specification as open to inspection under Sect. 91 comprises the following additional examples: (3) Piece goods are impregnated with a solution containing the anilide of 2 : 3-oxynaphthoic acid, caustic soda and turkey red oil, dried, printed with an aqueous paste as in (2), dried, passed through a solution containing the diazonium chloride of 4-amino-4<1>-methoxydiphenylamine and magnesium sulphate, squeezed and passed through water at 50 DEG C. and thereafter through sodium bisulphite solution, rinsed and soaped to obtain white resist effects on a navy blue ground. (4) Piece goods are impregnated and dried as in (3), printed with an aqueous paste containing the acid 1 : 5-naphthalenedisulphonate of diazotized 5-chloro-2-toluidine, aluminium sulphate and neutral starch-tragacanth thickening, dried, passed through a solution containing diazotized 4-aminodiphenylamine and magnesium sulphate, squeezed, passed through water at 50 DEG C. and thereafter through sodium bisulphite solution, rinsed and soaped to obtain red resist effects on a navy blue ground. (5) Piece goods are impregnated, dried, printed and dried as in (3), passed through a solution containing the diazonium chloride of 4-amino-3-ethoxy-4<1>-methyldiphenylamine and magnesium sulphate, squeezed, passed through water at 60 DEG C., rinsed and soaped to obtain a vivid reddish blue print. This subject-matter does not appear in the Specification as accepted.