Process for the filling of leather and compositions therefor

Claim 1

In a process for the filling of leather tanned with mineral, vegetable and/or synthetic tanning agents, the improvement which consists of treating the leather in the acid pH-range, with an aqueous solution of a filling agent consisting of a. a homopolymer or copolymer selected from the group consisting of acrylic acid, methacrylic acid, α-ethylacrylic acid, α-isopropylacrylic acid, α-butylacrylic acid and α-chloroacrylic acid or b. copolymers formed from a monomer of component (a) as defined above and a vinyl unsaturated monomer selected from the groups consisting of α. water-soluble comonomers containing carboxylic acid groups, carboxylic acid amide groups and their N-hydroxyalkyl derivatives, water-soluble derivatives of β-hydroxyalkyl acrylic or methacrylic acid amides, or aldehydes capable of copolymerisation; and β. water-insoluble comonomers consisting of optionally substituted acrylic or methacrylic acid alkyl esters having from 1 to 12 carbon atoms in the alkyl radical; vinyl esters of aliphatic carboxylic acids, containing from 1 to 12 carbon atoms, or mixtures of such carboxylic acids; or vinyl benzenes; and c. protein glue in a weight ratio of polymer to glue of from 1:12 to 12:1, alone or in admixture with further additives.