Disperse dyes

The dyes according to the invention consist of a chromophore and a radical which, on heating, forms an isocyanate or isothiocyanate group. The latter reacts with a suitable group in the environment. Dyeings of excellent thermomigration fastness are obtained. The disclosed dyes are of the formulae (1) or (2) where F is the radical of an azo, anthraquinone or tricyanovinyl dye which is free of water-solubilizing groups, B and B' are each independently of the other a direct bond or a bridge member, selected from the group consisting of a straight-chain or branched alkylene group having 2 to 8 C atoms or one of the following groups where R is hydrogen or C1-C6alkyl, n is an integer from 1 to 8 and m is an integer from 2 to 4, Z is O or S, V is a group which at a temperature between 180 DEG and 240 DEG C. is eliminated as a radical HV, and V' is a direct bond which is cleaved at a temperature between 180 DEG and 240 DEG C. or is a group which at such temperature turns, by ring opening and cleavage of the bond V'-C, into a group V'H, with the provisos that in the azo dyes the diazo component is not aminobenzisothiazole and the coupling component is not N-( beta -phenylureidoethyl)-1-naphthylamine when the diazo component is 2,4-dinitro-6-bromoaniline.