GB500582A - Improvements in or relating to the colouration of textile materials - Google Patents

Abstract

500,582. Colouring cellulose esters. MONCRIEFF, R. W., and COOKE, A. W. M. Aug. 13, 1937, No. 22305. [Class 15 (ii)] Textile and other materials, such as films, foils, sheets or moulded articles, having a basis of an organic ester of cellulose, are coloured by immersion in a liquid medimn containing a saponifying agent for the ester and a salt of an acid ester of a leuco vat dyestuff, followed by conversion of the salt into the vat dyestuff on the materials. Specified saponifying agents are methylamine, ethylenediamine, benzylamine, cyclohexylamine, guanidine, caustic soda or potash and alkali carbonates and, according to the Provisional Specification, any of the saponifying agents referred to in Specification 417,220 or 429,103. In an example, an aqueous liquor at 25‹ C. containing methylamine, Soledon jade green XS and Indigosol olive green IB, with an addition of sodium chloride, if desired, to increase the depth of shade, is passed for 5 hours alternately from the outside to the inside and vice versa of perforated bobbins carrying stretched cellulose acetate yarn, the bobbins are washed with cold water and dilute nitrous acid is then similarly passed to-and-fro for ¢ hour during which the temperature is raised to 60‹ C. ; a full green shade, fast to scouring, is obtained ; the dyestuffs may be replaced by Soledon blue 4BCS to obtain a blue shade. According to the Provisional Specification an agent, e.g. copper, which accelerates the saponification, may be employed as described in Specifications 430,349 and 430,351.