Method of dyeing wool with acid dyestuffs

Claim 1

A process for dyeing a textile substrate comprising wool fibers, which process comprises bringing the substrate into contact with an aqueous dyebath containing a monosulfonated acid dyestuff or a mixture of monosulfonated acid dyestuffs, said dyestuff or mixture having (a) a build up power such that it exhausts onto wool to an extent of 90 to 98% in 60 minutes from a dyebath having a temperature of 98±1° C., a pH of 4.5, a goods: liquor ratio of 1:40 and a dyestuff concentration as required for a 2/1 standard dyeing depth, and (b) a migrating ability such that it is capable of migrating to an extent of 25 to 40% in 60 minutes from a wool sample dyed in a 1/1 standard dyeing depth to an initially undyed wool sample of equal weight in a bath having a temperature of 98±1° C., a pH of 4.5 and a goods:liquor ratio of 1:40, said 25 to 40% being the ratio after said 60 minutes, of the amount of dyestuff on the initially undyed sample to the amount of dyestuff remaining on the dyed sample, and a leveling agent which is an alkoxylation product of an amine substituted by a C 12-30 alkyl or alkenyl group or by a C 13-31 alkylcarbonyl or alkenylcarbonyl group, provided that when the substrate is a wool/synthetic polyamide fiber blend the aqueous dyebath contains a mixture of monosulfonated acid dyestuffs.