GB400248A - Improvements in or relating to the production of discharge effects on materials made of or containing cellulose esters or ethers - Google Patents

Abstract

Cellulose esters or ethers, dyeing; printing.--Pattern effects are produced on materials made of or containing cellulose esters or ethers by the application thereto, before or after colouration with a dischargeable ground colour, of a composition, preferably of acid reaction, containing a stannous compound and a leuco derivative of a vat dyestuff esterified with a di-or poly-basic acid or a salt of such esterified leuco derivative. The stannous compound may be, for example, the chloride, chloracetate or thiocyanate and the use of a stannous thiocyanate or of a stannous compound in conjunction with a thiocyanate, as described in Specification 342,333, is particularly advantageous. The leuco derivative may be a water-soluble salt of a sulphuric or phosphoric acid ester of a leuco-indigoid or leuco-anthraquinone vat dyestuff, e.g. one of the compounds sold under the registered Trade Marks "Indigosol" or "Soledon." Swelling agents or assistants, e.g. hydroquinone, alcohols, organic acids, phenols or anthraquinone may be incorporated in the discharge composition. Additional dyestuffs such as the anthraquinone dyes used in the process of Specification 351,457 may also be present. In an example, a cellulose acetate fabric, dyed with the azo dye 3 : 5-dinitro-o-anisidine --> o -oxyethyl-a -naphthylamine, is printed with an aqueous composition containing Indigosol yellow HCG, gum arabic, methylated spirit, sodium thiocyanate, citric acid and stannous chloride, and is thereafter aged, treated in an atmosphere of ammonia, steamed, washed, treated in a bath containing sodium bichromate and formic acid, washed and dried to obtain a yellow pattern on a blue ground.