GB490532A - Improvements in or relating to the colouration of textile fabrics - Google Patents

Abstract

Colour effects are produced upon pile fabrics by dyeing the pile fibres before or after applying locally to such fibres agents causing only the tips or only the portions other than the tips of the fibres to be coloured by the dyestuff. Thus a chemical or mechanical resist or an agent adapted to alter the chemical character of the tips, e.g. an esterifying or saponifying agent, may be applied to the tips before dyeing the fibres or such fibres may first be dyed throughout their length and an agent for producing a white or coloured discharge be applied thereafter to the tips. In all cases undyed portions of the pile fibres may be separately dyed a colour different from that used in the main dyeing operation. The agent may be applied to the tips (a) by smooth or engraved plates or rollers carrying the agent and contacting lightly with the pile surface, (b) through a silk or other screen, or (c) by a wick supplied with the agent. Alternatively, the portions of the pile fibres other than the tips may be treated with a suitable agent, e.g. by application from the back of the fabric. In examples; (1) the cotton backing of a fabric having a cellulose acetate pile is first dyed with Diazo brilliant blue BBL developed with b -naphthol, the pile is then raised by brushing and upon it is pressed a layer of cellulosic material impregnated with caustic potash solution, where-upon the fabric is steamed, rinsed in dilute acid, washed and treated with a soap bath dispersion of 1 4-dimethylaminoanthraquinone; the saponified tips of the pile fibres remain undyed while the unsaponified portions are dyed blue; (2) the cotton backing of a similar fabric is similarly dyed and an aqueous paste containing caustic potash and British gum is applied to the tips of some of the pile fibres by printing from an engraved roller, the fabric is dried, hung for several hours in a warm dry atmosphere and rinsed with dilute acetic acid, washed and the pile fibres other than the saponified tips are dyed with 1-methylamino-4-ethanolaminoanthraquinone; (3) the brushed-up regenerated cellulose pile of a fabric having a cotton backing is placed in contact with a regenerated cellulose film coated with paraffin wax, the whole is passed through a hot calender to transfer the wax to the pile fibre tips, the fabric is dyed with Chlorazol fast red KS, immersed in hot water to remove the wax, dried and finished; (4) a fabric having a cotton backing is dyed in a bath at 75-80 DEG C. containing Glauber salt, Chlorazol black LF (for the cotton) and p-aminobenzene-azo-dimethylaniline (for the cellulose acetate) and washed, the dyeing is diazotized and developed with 2 : 3-hydroxynaphthoic acid to obtain a black dyeing throughout and an aqueous paste containing gum tragacanth, glycerol, thiodiglycol and zinc formaldehydesulphoxylate is then applied by brushing to the fibre tips to discharge the dyeing therefrom.