Process for the simultaneous tanning and dyeing of collagen containing fibrous material

A process for the simultaneous tanning and dyeing of collagen containing fibrous material, the process comprising

• treating a collagen containing fibrous material with an aqueous liquor comprising at least one reactive dyestuff, wherein the aqueous liquor has a pH less than a pH required to fix the at least one reactive dyestuff, and wherein treating comprises distributing the at least one reactive dyestuff throughout a thickness of the material;
• and
• increasing the pH of the aqueous liquor to simultaneously tan the fibrous material by crosslinking the fibrous material and fix the dye to the fibrous material, wherein the at least one reactive dyestuff is selected from the group of formula (1) and (2)
• wherein
• A1, A2 and A3 are each independently of the others the radical of a monoazo, polyazo, metal-complexed azo, anthraquinone, phthalocyanine, formazan or dioxazine chromophore having at least one sulfo group,
• B is an organic bridge member,
• Q1, Q2, Q3 and Q4 are each independently of the others hydrogen or unsubstituted or substituted C1-C4 alkyl,
• G1 und G2 are halogen, 3-carboxypyridin-1-yl or 3-carbamoylpyridin-1-yl,
• (Z1)2-3 is 2 to 3 identical or different fiber reactive radicals,
• Z2 and Z3 are each independently of the other identical or different fiber reactive radicals, and b is the number 0 or 1
• wherein the process does not include chrome, vegetable and aldehyde tanning agents.