Method for dyeing leather with water-soluble sulpho group-containing sulphur dyes
AssigneeSandoz Ltd.
InventorMichel Dien
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Abstract
Tanned leather is penetration-dyed from aqueous medium with hydrospluble sulpho group-containing sulphur dyes in the presence of dye-substantive uptake assistants and may be used as a substrate for further coloration processes, mainly dyeings and printings, in particular with anionic or basic dyes; in a variation of the process for overdyeing, in particular of thin leathers, the penetration-dyeing may also be carried out in the absence of the dye-substantive uptake assistant.
Claims28
A process for the penetration dyeing of tanned leather which comprises dyeing the tanned leather in an aqueous medium with a hydrosoluble sulpho group-containing sulphur dye in the presence of a dye-substantive uptake assistant which is a surface-active quaternized or non-quaternized fatty amine or fatty aminoalkylamine, said amine or aminoalkylamine containing an aliphatic linear hydrocarbon radical of at least 12 carbon atoms and being oxyethylated with at least 20 moles of ethylene oxide per mol and the alkylene bridge of said aminoalkylamine being linear polymethylene of 2 to 6 carbon atoms.
A process for dyeing tanned leather which comprises dyeing very thin leather with hydrosoluble sulpho group-containing sulphur dyes from aqueous medium in the absence of a dye-substantive uptake assistant and overdyeing said leather with a hydrosoluble basic dye.
Dependencies are inferred from the claim text.