Azo dyes, their production and use

A process for producing an azo dye (Z) containing at least one azo group and at least one chromophoric radical wherein at least one chromophoric radical comprises a radical of an optionally modified, optionally (pre)reduced sulphur dye (S) or a mixture thereof, which process comprises

• a) coupling the diazonium compound of at least one optionally modified, optionally (pre)reduced sulphur dye (S.sub.1), optionally over at least one middle component (Mk), to at least one coupling component (B) and optionally further modifying the resulting product, or
• b) reacting at least one azo-group-containing diazonium compound (Dz) with at least one optionally modified, optionally (pre)reduced sulphur dye (S.sub.2) and optionally further modifying the resulting product.

A process according to claim 14 wherein the dye (S) is selected from the group consisting of C.I. Leuco Sulphur Blacks 1, 2, 11 and 18, C.I. Leuco Sulphur Reds 10 and 18, C.I. Leuco Sulphur Blues 3, 7, 11, 13, 15 and 20, C.I. Reduced Vat Blue 43, C.I. Leuco Sulphur Greens 2, 16, 35 and 36, C.I. Leuco Sulphur Browns 1, 3, 10, 21, 26, 31, 37, 52, 95 and 96, C.I. Leuco Sulphur Orange 1, C.I. Leuco Sulphur Yellows 9 and 22 and the corresponding non-reduced or non-leuco dyes.

A process which comprises diazotizing an optionally modified, optionally (pre)reduced sulphur dye which contains at least one aromatically linked --NH.sub.2 group to form a diazo compound and coupling said diazo compound to a compound capable of a coupling reaction.