GB190712219A - Improvements in Dyeing with Sulphur Colouring Matters and Preparations for use therein. - Google Patents

Abstract

12,219. Johnson, J. Y., [Badische Anilin & Soda Fabrik]. May 27. Dyeing with sulphur colouring-matters in a fermentation vat. Sulphuretted dyes, or leuco-, or hydro-compounds thereof, instead of being used with such a reducing-agent as an alkaline hyposulphite, are mixed with fermentable matter and then with or without other suitable compounds, they yield on treatment with water in the presence of an alkali, or alkaline substance, a direct dyeing vat. The mixture may be made dry or as a paste, the addition of the alkaline substance being optional in the former case, but advisable in the latter, to ensure keeping. The fermentation, which is carried out when the mixture is stirred, with addition of alkaline substance if necessary, into hot or cold water, reduces the dye to the leuco condition, giving a vat suitable for animal or vegetable fibre, particularly the latter. When starting with a jeuco- or hydro-compound, the fermentable substance helps to prevent its oxidation. The use of several dyes is referred to, for example kryogene black TBO, sulphur black T, immedial black NNG, thiophenol black T extra, kryogene direct blue G, and others. Of these, the first, for example, may be made into a paste, which can be pressed into cakes, with finely ground wheat-bran, potato flour, calcined soda, and sugar syrup ; or it may be mixed with water, bran, wheat or potato flour, calcined soda, and syrup or molasses to form a bath which is maintained weakly alkaline with sodium carbonate and may be strengthened for fresh dyeing operations by adding the various materials. Another bath contains kryogene direct blue G, wood, bran, caustic soda, and syrup.