Process for the dyeing of polyamide fibers with sulphur dyestuffs

In the single bath dyeing of polyamide fibers and blends of polyamide and cellulose fibers with aqueous solutions of reduced sulphur dyestuffs wherein the fibers are dyed in an aqueous dye liquor in a liquor ratio of 1:5 to 1:30 at a temperature of from 60 to 130.degree. C., the improvement which comprises adding to each liter of said aqueous solution 2 to 20 grams of a dye accelerator of the formula ##SPC10##

• wherein:
• A taken separately is hydrogen, halogen, hydroxy or alkoxy or alkyl having 1 to 4 carbon atoms;
• B taken separately is --COOR.sup.1 or --Y--Z.sup.1 --M or
• A and B taken together are of the formula ##SPC11##
• Y is a direct bond, --O--, --S-- or --CO--;
• Z.sup.1 is alkylene having 1 to 4 carbon atoms or alkenylene having 2 to 4 carbon atoms;
• M is --COOR.sup.2 or ##EQU2## Z.sup.2 is hydrogen, halogen, hydroxy or alkyl or alkoxy having 1 to 4 carbon atoms;
• Z.sup.3 is hydrogen, halogen, hydroxy, alkyl or alkoxy having 1 to 4 carbon atoms or when B is --COOR.sup.1, Z.sup.3 may be --COOR.sup.1 ;
• R.sup.1 and R.sup.2 are the same or different and are alkyl having 1 to 6 carbon atoms;
• alkenyl having 2 to 6 carbon atoms;
• one of said alkyl or alkenyl radicals substituted by alkoxy-alkoxy having 2 to 8 carbon atoms, hydroxy, alkoxy having 1 to 4 carbon atoms or halogen;
• phenyl;
• benzyl;
• phenethyl;
• phenoxyethyl or phenyl, benzyl, phenethyl or phenoxyethyl having their phenyl nuclei substituted by halogen, hydroxy or alkoxy or alkyl having 1 to 4 carbon atoms;
• R.sup.3 is alkyl having 1 to 8 carbon atoms and
• R.sup.4 is hydrogen, alkyl having 1 to 8 carbon atoms, phenyl, alkenyl having 2 to 4 carbon atoms or haloalkyl, dihaloalkyl, cyanoalkyl, hydroxyalkyl, alkanoyloxyalkyl, alkoxyalkyl or phenylalkyl, each alkyl moiety having 1 to 3 carbon atoms.