Process for dyeing or printing cellulosic textile materials with vat dyes or sulphur dyes

摘要

Process for dyeing or printing cellulosic textile materials with vat dyes or sulphur dyes by applying the water-insoluble dye to the textile material from an aqueous liquor or as a print paste, reduction to the leuco form in an aqueous alkali medium using iron(II) compounds as reductants and subsequent oxidation to the pigment, by using as the iron(II) compound iron(II) complex salts with hydroxycarboxylic acids as complexing agents which have a molar ratio of iron(II) to complexing agent from 1 : 3 to 1 : 0.5. The wastewaters obtained are advantageously given a biological treatment and can be re-used for dyehouse purposes.