GB887437A - Dyeing of textile materials made from blended cellulose and hydrophobic fibres - Google Patents

Abstract

Textile materials consisting of blended cellulose and hydrophobic fibres are dyed with azoic dyes, with azoic dyes in conjunction with disperse acetate dyes or reactive dyes, or with disperse acetate dyes in conjunction with reactive dyes, by padding the material in a cold bath containing at least one of these dyestuffs or at least one component of an azoic dyestuff, removing excess liquor and subjecting the padded material to treatment in a fluidised bed of solid discrete materials maintained at a temperature of between 100 DEG C. and 250 DEG C. for a short period (e.g. between 5 and 90 seconds), whereby the padded material is first dried and the dyestuff or dyestuff component is fixed on the dried material, which is then subjected to diazotisation and coupling where azo dyes are used. The hydrophobic fibres may be polyethylene terephthalate, cellulose acetate or triacetate, polyamides, or polyacrylic fibres, expecially polyacrylonitriles. Desirably, the naphthol component of an azo dye is dissolved in an alkaline solution, e.g. caustic soda, preferably in sufficient quantity to form the sodium naphtholate with slight excess of alkali. In a preferred method there is applied to the textile material from one or more baths a naphthol component of an azoic dye and two base components therefor, or the naphthol component and one such base component together with a dyestuff for one of the fibres, treatment in each bath being followed as appropriate by treatment in the fluidised bed, which treatment is followed by diazotisation to effect coupling of the azoic dye or dye components. Alternatively, a textile material consisting of blended polyethylene terephthalate fibres and cellulose fibres may be padded successively in two baths, the first containing a disperse acetate dye and the naphthol component of an azo dye and the second containing a base component, in the form of a diazotised salt, for the azo dye. In another preferred method, a textile material consisting of blended cellulose and hydrophobic fibres, especially polyethylene terephthalate fibres, is padded in an alkaline bath containing a reactive dye and a disperse acetate dye. The padding bath may incorporate a wetting agent and a dyeing assistant selected from the group consisting of glycerine, triehanoalmine, diacetin, erythritol, pentaerythritol, ethylene glycol, diethylene glycol, diethylene glycol diacetate, d-glucose monohydrate, thiourea, urea, ammonium thiocyanate, hexamine, a mixture of urea and ethylene glycol, a mixture of pentaerythritol and thiourea, a mixture of glycerine and thiourea, and a mixture of diethylene glycol diacetate and thiourea. Specifications 773,598 and 814,526 also are referred to.