Process for the dyeing of leather with anionic dyes and polyaminoamide resin as dyeing auxiliary

Process for the dyeing of leather by means of anionic dyestuffs, characterized in that polyaminoamide resins are used as auxiliaries for the dyeing obtainable by condensation of at least one amine from the series

• a) diamines of the formula ##STR6## in which R.sub.1, R.sub.3, independently of one another, represent hydrogen, unsubstituted or hydroxylsubstituted C.sub.1 -C.sub.10 -alkyl, or a radical formed-by addition of 2-4 ethylene oxide, propylene oxide and/or butylene oxide, and
• represents C.sub.2 -C.sub.9 -alkylene or a divalent radical of the formula ##STR7## n represents 1 or 2, m, l represents 0 or 1 and
• p represents 0, 1, 2 or 3,
• b) piperazine derivatives of the formula ##STR8## in which R.sub.4, R.sub.5, independently of one another, represent hydrogen, C.sub.1 -C.sub.4 -alkyl or the radical R.sub.6 -NH-R.sub.7 -,
• R.sub.6 represents C.sub.1 -C.sub.4 -alkyl and
• R.sub.7 represents C.sub.2 -C.sub.4 -alkylene, and
• c) polyamines of the formula ##STR9## in which R.sub.8 represents hydrogen or unsubstituted or hydroxyl-substituted C.sub.1 -C.sub.4 -alkyl,
• R.sub.9, R.sub.10 independently of one another, represent hydrogen, methyl or ethyl,
• q, r, independently of one another, represent 0, 1, 2, 3 or 4 and
• s, t, independently of one another, represent 1, 2, 3, 4, 5 or 6,
• with at least one aliphatic saturated C.sub.2 -C.sub.12 -dicarboxylic acid, olefinically unsaturated C.sub.4 -C.sub.12 -dicarboxylic acid or aromatic dicarboxylic acid or functional derivatives thereof and, if desired, a C.sub.3 -C.sub.8 -.omega.-aminocarboxylic acid or its lactam, in which the amines of the formulae (I), (II) and (III) and the dicarboxylic acids or their derivatives are reacted with one another in such amounts that a molar excess of the amino groups with respect to the carboxyl groups results.