GB436076A - Improvements in stripping dyed textiles - Google Patents

Abstract

Textiles dyed with azoic colours are stripped by a modification of the process described in the parent Specification which comprises including in the stripping bath a small proportion, e.g. 0,05 per cent by weight of anthraquinone, a substituted anthraquinone carrying as substituents hydroxyl, halogen, amino or alkyl groups, or a combination of such groups. It is stated that the process can be carried out at a lower temperature, and that it is particularly suitable for stripping azoic colours from natural silk. In examples: (1) Cotton yarn dyed with 4-chloro-2-aminotoluene --> (on the fibre) diacetoacetictoluidide is treated for 30 minutes at 85--90 DEG C. in 40 times its weight of an aqueous solution containing caustic soda, sodium hydrosulphite, and trimethylcetylammonium bromide having dispersed in it powdered anthraquinone. (2) Cotton yarn dyed with 5-chloro-2-aminotoluene --> (on the fibre) Brenthol AS is similarly stripped, whereas if the anthraquinone is omitted, a pale red shade remains. (3) Cotton yarn dyed with 5-nitro-o-anisidine --> (on the fibre) Brenthol BT is similarly stripped. (4) Yarn dyed with 5-nitro-o-anisidine --> (on the fibre) Brenthol AT is similarly stripped. (5) Cotton yarn dyed with dianisidine \sy (on the fibre) Brenthol BA is similarly stripped. (6) Pure silk yarn dyed with fast Red KB base --> (on the fibre) Brenthol BA is similarly stripped. The yarn may be given an after treatment with hydrogen peroxide. Specifications 294,582, [Class 2 (iii)], 392,763, and 379,396 are referred to.