Patent ID: 8382857
Filing Date: 2013-02-26
Classification: C09B,D06P

Abstract:
1. A process comprising treating leather with at least one anionic polyazo dye F, or a metal complex thereof, which has at least 3 diazo groups and at least one alkaline-activatable group of the formula A; wherein - - - - denotes the bond to the dye or metal complex thereof; X is C k is 0, 1, 2 or 3, n is 0 or 1 and B is a CH═CH wherein the dye F, or metal complex thereof, is selected from the dyes of the general formulae I to VII: wherein n and p are independently 0 or 1; m is 0, 1 or 2 subject to the condition that m+p=2 or 3 in the formula I; Dk Kk Kk Tk P and R′ independently represent a divalent aromatic radical of benzene or naphthalene which may each optionally comprise one or more of the following radicals as substituents: SO Napht and metal complexes of these dyes, wherein the process obtains a fixation rate of 85% or more.