PROCESS FOR DYEING DIFFERENTIAL-DYEING FIBRES
The present invention relates to a process for the differential dyeing of such polyamide fibres and materials containing polyamide fibres as are made of components which differ in dyeability, or mixtures of polyamide fibres, with dyes or dye mixtures, which comprises using for dyeing these materials an aqueous liquor which contains a dye of the formula < IMG > (1) in which A1 is hydrogen or C1-4-alkyl and R is a C2-5-alkanoyl, C3-6-alkenoyl, phenoxycarbonyl, C1-4-alkylsulfonyl or phenylsulfonyl radical which can be substituted in the alkyl, alkenyl, phenoxy or phenyl moiety, or a mixture of a dye of the formula (1) with a monosulfo-containing anthraquinone dye, and to those dyes of the formula (1) in which A1 is as defined above and R is a C1-4-alkylsulfonyl or phenylsulfonyl radical which can be substituted in the phenyl moiety by C1-4-alkyl. Even at low dyeing temperatures, the process of the invention gives ombre effects rich in contrast and, on admixture of other suitable acid dyes, multicolour effects on polyamide fibres which are suitable for differential dyeing.