METHOD OF MAKING LEATHER Russian patent published in 2013 - IPC C14C3/04 

FIELD: chemistry.

SUBSTANCE: method involves pickling a hide, tanning with a titanium-aluminium tanning agent with particle size not greater than 50 nm in the presence of cationic fat, alkanising the treating solution in two steps: first with magnesium oxide and then with a mixture of sodium formate and sodium bicarbonate, pressing, shaping, retanning with a chrome tanning agent in the presence of cationic fat, dyeing and oiling processes, drying and finishing by depositing a clear prime coat and a pigment finish based on aqueous dispersions of acrylic copolymers and a pigment concentrate containing a nanosize pigment. Tanning with a titanium-aluminium tanning agent is carried out for 1.5-2.0 hours, alkanisation of the treating solution with magnesium oxide is carried out for 30-40 minutes, with a mixture of sodium formate and sodium bicarbonate - for 20-30 minutes and retanning with a chrome tanning agent is carried out for 40-60 minutes.

EFFECT: invention speeds up leather treatment processes and improves operational properties of titanium-aluminium tanned leather for the upper part of shoes.

3 tbl, 4 cl