PROCESS FOR TANNING LEATHER WITH ACRYLIC POLYMER AND MINERAL TANNING AGENT AND LEATHER SO PRODUCED

摘要

In the tanning of heavy leather, leather stock is subjected to a multiple-stage tanning process under carefully controlled pH conditions to improve its characteristics such as fullness and firmness. Leather stock at a pH of from 4.5 to 5.5 is treated with polymer containing units of acrylic and/or methacrylic acid and optionally, at least one of acrylic ester, methacrylic ester and partially sulfated drying oil and then, at a pH of from 1 to 3.3 treated with a mineral tanning agent. Preferably the mineral tanning agent comprises a zirconium tanning compound having a basicity on the Schorlemmer scale of from 0 to 45%, a buffered aluminum sulfate tanning compound or a mixture thereof. The leather is subsequently neutralised, washed and dried and may be used for shoe soles, belts, straps, bags, cases, saddles, bridles and harnesses.