Process for the production of reserve effects on polyester textiles and polyester/cellulose mixed fibre textiles: discharge printing with disperse azo dye with alkyl or alkoxy carbonyl, cyand and hydroxy phenyl group

In the process for the preparation of white patterns or patterns of various colors on a colored substrate on textile materials comprising hydrophobic synthetic fibres or on textile materials based on mixed fibres composed of polyester and cellulose comprising impregnating the materials with dye liquores which, besides the customary dyeing and padding auxiliaries, contain disperse dyestuffs which are dischargeable to white, and if mixed fibre textiles are processed, contain, optionally, reactive dyestuffs which are dischargeable to white and which have, as a reactive anchor, a group of the formula

• --SO.sub.2 --CH.sub.2 --CH.sub.2 --Hal,
• --SO.sub.2 --CH.sub.2 --CH.sub.2 --O--SO.sub.3 M,
• --NH--SO.sub.2 --CH.sub.2 --CH.sub.2 --O--SO.sub.3 M and
• --SO.sub.2 --CH.dbd.CH.sub.2
• and printing on, in the desired pattern, a discharge reserve paste which, besides the discharge reserving agent, also contains, optionally, dyestuffs which are resistant to discharging agents, and by subsequently subjecting the material to a heat treatment at temperatures of 100.degree. to 230.degree. C., in which process, if no reactive dyestuffs which are dischargeable to white are present, the discharge reserving agent employed is a base which produces a pH value of at least 8 in a 5% strength aqueous solution, or is a discharge reserving agent based on sulphites which contains an alkali metal sulphite or an alkali metal bisulphite in combination with an alkali metal carbonate or bicarbonate and, optionally, an aldehyde, and which, optionally contains a nonionic detergent, and if the abovementioned reactive dyestuffs which are dischargeable to white are present, the discharge reserving agent based on sulphites is employed, the improvement which comprises employing as the dischargeable disperse dyestuffs, dyestuffs having the formula I ##STR35## in which R is optionally substituted alkyl having 1 to 8 carbon atoms, optionally substituted alkoxy having 1 to 8 C atoms, and K is the radical of a coupling component of the benzene, naphthalene, pyridine, benzpyridine, diazole, thiazole, indole, carbazole, oxazole or diazine series or the series of enolisable 1,3-dicarbonyl compounds, the molecule of which dyestuffs contains not more than one esterified carboxyl group.