GB848459A - Improvements in or relating to fugitive dyestuffs or tints derived from reactive anionic dyestuffs - Google Patents

Abstract

A fugitive dyestuff for tinting fibres for identification is made by causing a carbohydrate of relatively high molecular weight such as starch, degraded starches, or dextrines such as British gum, to react and combine with a reactive anionic dyestuff of the azoic or anthraquinonoid type containing solubilizing sulphonate groups and either a mono- or dichlortriazinyl group which is capable of fixation on cellulosic fibres by chemical linkage. The components of the fugitive dye may be combined in the presence of alkali, e.g. sodium carbonat or bicarbonate, preferably at a pH of 10. In applying the tint to a textile material, which may consist of or contain any natural or synthetic fibre, a solution in water of the compound of reactive anionic dyestuff and carbohydrate is prepared and this solution is applied by spraying, by immersion, or by means of a roller. A textile spinning oil, or an organic sulphonic acid, e.g. toluene sulphonic acid, or other additives may be incorporated in the solution. The tints may subsequently be removed by washing with the aid of a detergent. In the production of the fugitive dye, the carbohydrate and reactive dyestuffs may be heated together in aqueous alkaline solution. The solution is then cooled and the complex is precipitated by adding ethyl or methyl alcohol. The product is washed with aqueous alcohol and may then be dissolved in water. Alternatively, the aqueous alkaline solution may be passed through an anionic exchange resin which retains unreacted dye but allows the complex to pass through, or the solution may be subjected to dialysis, the complex being retained by the membrane.