Continuous pad dyeing of cellulose textiles in width form - with water soluble sulphur dyes utilising sodium polysulphide solns. to inhibit spontaneous oxidn. of dyes

摘要

The continuous dyeing of widths of cellulose fibres with water-sol. sulphur dyes by a padding process without subsequent steam-fixing of the dyestuff comprises (a) first padding the textile matl. on a foulard at relatively low bath uptake at 40-50 degrees C with an aq. soln. contg. one or more water-sol. S dyes (solubilised sulphur dyes) and 20-30% as sulphide requirement for the complex redn. of the dyestuff (in the SH-form) of sodium sulphide; (b) again padding the matl., with no intermediate drying, on a chemical foulard at an appreciably greater bath uptake, with a hot aqs. bath contg. a further 30-20% as specific sulphide requirement (see above) of sodium sulphide, such that in (a) and (b) the amt. of sodium sulphide used does not exceed 50% of the known sulphide requirement, this second padding liquor also contg. added aqs. sodium polysulphide soln; (c) exposing the textile to passage of air for at least 10 secs. and (d) as is usual for pad-dyeing with S dyes, finishing the dyeing by rinsing, oxidising and rinsing again to form the water-insol. disulphide form of the dyestuff on the fibre. The sodium poly-sulphide has the novel action of inhibiting the spontaneous oxidn. of the sulphhydryl form of the dyestuff during the passage through air stage, and thus facilitates complete diffusion of the dyestuff into the fibre and its fixation. Deep, uniform dyeings are obtd. with full dyestuffs yields.