GB670546A - Process for dyeing tanned fur skins - Google Patents

Abstract

Fur skins tanned predominantly or exclusively with chromium compounds (especially chrometanned lamb and sheep skins) are dyed on the finely-fluffed flesh side, with reservation of the wool or hair, by pretreating them with aqueous solutions of capillary active organic compounds and then dyeing them in the presence of capillary active organic compounds (in a fresh bath or in the pretreatment bath) with dyestuffs which have but little affinity for the wool or hair (preferably substantive dyes). If desired the wool or hair may be dyed the same or a different colour with other dyestuffs (advantageously acetate rayon dyestuffs) in the same or a different bath. Greater penetration of the leather by the dye may be achieved by adding ammonia to the dye-bath to a pH of at most 9.2, and acidifying the bath, shortly before the ending of the dyeing, to an acidity not exceeding that of pH 3.3. In examples: (1) chrome-tanned sheep-skins are pretreated with a solution of sulphonated lauryl alcohol and dyed with Solar Brilliant Red BA in the presence of the same capillary active compound; (2) skins are pre-treated as in (1) and dyed in the same bath with Derma Brown R with the addition of a further amount of the capillary-active compound; (3) skins pretreated as in (1) are dyed with Solar Brilliant Red BA in the presence of an alkylarylpolyglycol ether in a bath made alkaline with ammonia to pH 9.0 and afterwards acidified with acetic or formic acid to pH 3.5; (4) skins pre-treated as in (1) are dyed with Derma Brown R for the flesh side and Artisil Direct Grey BLP for the wool, in the presence of the sulphuric acid ester of a mono-fatty-acid glycerol ester. Other suitable capillary active compounds are specified. The Specification as open to inspection under Sect. 91, comprises also the washing of the skins with a fatty alcohol sulphonate solution, followed by rinsing, centrifuging and drying, in cases where the wool shows a slight colouration. This subject-matter does not appear in the Specification as accepted.