Patent ID: 8007546

Claim:
A method of increasing the depth of shade of dyed natural or synthetic polyamide fibre materials, which comprises treating the fibre material before, during or after dyeing with a liquor comprising a compound of formula (1) wherein R is halogen, C 1 -C 12 alkyl, C 5 -C 24 aryl, C 6 -C 36 aralkyl, —OR 1 or —NR 1 R 2 , R 1 ; and R 2 being, each independently of the other, hydrogen, C 1 -C 12 alkyl unsubstituted or substituted by one or more hydroxy, amino, mercapto, carboxyl, sulfo, C 1 -C 12 alkylsulfonyl, C 5 -C 24 arylsulfonyl or C 6 -C 36 aralkylsulfonyl groups, C 5 -C 24 aryl unsubstituted or substituted by one or more hydroxy, amino, carboxyl, sulfo, C 1 -C 12 alkylsulfonyl, C 5 -C 24 arylsulfonyl or C 6 -C 36 aralkylsulfonyl groups, or C 6 -C 36 aralkyl unsubstituted or substituted by one or more hydroxy, amino, carboxyl, sulfa, C 1 -C 12 alkylsulfonyl, C 5 -C 24 arylsulfonyl or C 6 -C 36 aralkylsulfonyl groups; X and Y are, each independently of the other, mercapto, or —NR 3 R 4 , wherein R 3 and R 4 are, each independently of the other, hydrogen or C 1 -C 12 alkyl; R 6 and R 7 are, each independently of the other, hydrogen or C 1 -C 12 alkyl; and x and y are, each independently of the other, a number from 2 to 12.