GB669192A - Process for the dyeing of furs and skins - Google Patents

Abstract

Furs and skins are dyed in a dye-bath which contains 10 per cent or more of a water-miscible aliphatic low molecular alcohol or ketone or ester or a mixture of these liquids. Suitable liquids are ethyl alcohol, glycol, acetone and ethyl acetate. The dyestuffs may belong to any desired group as, for example, azo dyes, triarylmethane dyes, anthraquinone dyes and complex metal compounds of azo dyes, many examples being given. The ratio between the organic liquid and water may be adjusted only towards the end of the dyeing process, or the dyestuff may be added in stages, it being necessary only to ensure that the solubility of the dyestuff in the mixture existing at any moment is still sufficient. An acid may be added to the dye-bath which may also contain a capillary-active substance, and the skins may be pre-treated, for example, by wetting them with the liquid mixture to be used in the dyeing. The process is particularly suitable for dyeing sheepskins which have been treated to render them similar to furs as by the processes of Specification 505,487, [Group VIII], and French Specifications 759,162, 808,707 and 840,277. In examples: (1) dressed sheepskins are dyed with the complex cobalt compound of the dyestuff from diazotized 4-nitro-2-amino-1-hydroxybenzene and 1-phenyl-3-methylpyrazolone from a bath containing formic acid, alcohol and water; (2) improved shorn lambskin is dyed in a bath containing the chromium complex of the dyestuff from 1-diazo-2-hydroxynaphthalene-4-sulphonic acid and 1-phenyl-3-methylpyrazolone, formic acid, acetone and water; (3) dressed sheepskin is dyed with a bath containing the dyestuff from diazotized 1-amino-2-nitro-4-methylbenzene and 3-methylpyrazolone, the chromium-aluminium complex of the dyestuff from diazotized 5 - nitro - 2 - amino - 1 - hydroxybenzene and 1-phenyl-3-methylpyrazolone, the chromium complex of the dyestuff from diazotized 5 - nitro - 2 - amino - 1 - hydroxybenzene and 2-hydroxynaphthalene, formic acid, the sodium salt of N-benzyl-m -heptadecylbenzimidazole disulphonic acid, alcohol and water; and (4) shorn lambskin is pre-treated in a bath containing alcohol, water and formic acid and dyed with a mixture of complex metal azo dyestuffs by adding a solution of the dyes in alcohol at intervals to the pretreatment bath. The Specification as open to inspection under Sect. 91 comprises also the dyeing of wool and other animal fibres and includes an example of the dyeing of wool. This subject-matter does not appear in the Specification as accepted.