Patent ID: 6890359

Claim:
A process for controlled partial decolorization of vat- or sulfur-dyed or -printed cellulosic textile material, which comprises treating the cellulosic textile material to be lightened or decolorized with one or more compounds of the formula I R 1 3-z N(CR 2 R 3 —SO 2 M) z (I) where z is 1, 2 or 3, R 1 is a) when z is 1 or 2: hydrogen, alkyl of 1 to 18 carbon atoms or HOCH 2 CH 2 , b) when z is 2: additionally OH, and c) when z is 1: either as defined under a) independently for the two R 1 radicals or as defined under a) in one instance and as defined under b) in the other, R 2 and R 3 , which may be the same or different, are each hydrogen or alkyl of 1 to 4 carbon atoms subject to the proviso that together they have not more than 0.4 carbon atoms, and M is one equivalent of a mono- or divalent metal atom, at pH 4-7, optionally followed by an aftertreatment with hydrogen peroxide.