Verfahren zur Verbesserung der Echtheiten von Färbungen mit Säurefarbstoffen auf Textilmaterial aus Polyamiden

Aqueous solutions of alkali metal or ammonium salts of condensation products of formaldehyde or acetaldehyde and a sulphonic acid of a dihydroxydiphenylsulphone are used to aftertreat dyeings on synthetic polyamides. In the examples (1) 4,41-dihydroxydiphenylsulphone was reacted with H2SO4.H2O in acetic anhydride, the acetic anhydride was then removed by distillation and the reaction mixture reacted with 30% formaldehyde and latex neutralized with NaOH, (2) the same procedure was followed using a mixture of 85% 4,41-dihydroxydiphenylsulphone and 15% 2,41-dihydroxydiphenylsulphone as starting materials.ALSO:Dyeings produced with acid dyes on synthetic polyamide articles are after-treated with an aqueous solution of an alkali metal or ammonium salt of a condensation product of a lower aliphatic aldehyde, e.g. formaldehyde or acetaldehyde, and a sulphonic acid of a dihydroxydiphenylsulphone. The condensation product may be produced by reacting 1-1.5 mol sulphuric acid monohydrate with 1 mol dihydroxydiphenylsulphone followed by reaction with 0.5-1 mol aldehyde. Two examples are given using 4, 41-dihydroxydiphenylsulphone and a mixture thereof with 2, 41-dihydroxydiphenylsulphone.