GB729656A - Improvements in the fastness of coloured textile materials - Google Patents

Abstract

The fastness of dye or pigment colourations on textile materials is improved by the application, together with or after the application of the colouring matter, of a reaction product of an alkali metal bisulphite and an organic isocyanate or isothiocyanate, followed by heating at a temperature at least as high as the decomposition temperature of the reaction product, for example at 100-200 DEG C. The use of aliphatic monofunctional isocyanates or isothiocyanates containing more than 8 carbon atoms in the aliphatic radical is excluded. Reaction products of mono-, di-, or tri-functional isocyanates and isothiocyanates may be employed, examples of which are phenyl isocyanate, hexamethylene di-isocyanate, toluylene-2 : 4-di-isocyanate, m - phenylene - di - isocyanate, chlorophenylene - 2 : 4 - di - isocyanate, the mixture of polyisocyanates known as "Vulcafor" V.C.C. (Registered Trade Mark) and the corresponding isothiocyanates, allyl isothiocyanate, toluene-2 : 4 : 6-tri-isocyanate, mixtures of toluene 2 : 4-and 2 : 6-di-isocyanates and methylene bis-p-phenylene-isocyanate. The reaction product may be applied in solution or dispersion, or alternatively, the reaction product may be formed in situ on the material either by applying, in either order, an aqueous solution of the bisulphite and an organic solvent solution of the isocyanate or isothiocyanate, or by applying an emulsion of the isocyanate in an aqueous bisulphite solution. The reaction product may be applied locally as by printing or stencilling, or by the pre-application of resists or the subsequent application of a discharge paste prior to the heat treatment. The heating step may be effected by hot air, infra-red radiation, molten metal or steam. An amide, amidine or aminotriazine, e.g. urea, thiourea, acetamide, benzene sulphonamide, p-toluene sulphonamide, dicyandiamide, guanidine, aminoguanidine or melamine, may also be applied to the material to be present during the heat treatment. Cationic dye-fixing agents, such as are described in Specifications 464,921 and 515,847, and anionic dye-fixing agents, such as phospho-tungsto molybdic acid, may be applied to the dyed material before or simultaneously with the application of the reaction product. The process improves the fastness of dyes and organic and inorganic pigments, e.g. acid, chrome, direct, basic, dispersed, vat and insoluble azoic dyes, "onium" dyes as described in Specifications 613,980, 613,982, 613,983 and 619,035, iron oxide and hydrates, lead chromate, ferric-ferrocyanide, cadmium sulphide, phthalocyanine pigments, and fluorescent coumarins and "Lumogens," and the dye or pigment may be applied in aqueous or organic-solvent dispersion or emulsion, if desired as a dispersion or solution in an aqueous solution or dispersion of a natural or synthetic polymeric textile finishing substance, e.g. starches, gums, alginates, cellulose ethers, proteins, polyvinyl alcohol, partially hydrolysed polyvinyl acetate, polyacrylic acid and its water-soluble salts, condensates of formaldehyde with urea, melamine and phenol or alkyd resins. Numerous examples are given of the process applied to fabrics of cotton, viscose rayon, nylon, "Terylene" (Registered Trade Mark) and glass, and in some examples vat pigments are printed on cotton or nylon fabrics, the paste containing, in addition to the reaction product, methyl cellulose and urea or acetamide. The process may also be applied to natural, regenerated or modified protein textile materials. The simultaneous application of the reaction product and acid, chrome, direct, basic and insoluble acetate dyes to cellulosic materials (as described in Specification 716,233) is disclaimed. A marketable composition comprises a solid mixture of the pigment and the bisulphite-isocyanate reaction product.