| 摘要 |
In the tanning or re-tanning of a hide with a tanning composition comprising a tanning-active substance and at least one of a Cr(III) salt, a dicarboxylic acid, a dicarboxylic acid salt, an emulsifier and an acid-binding agent, the improvement which comprises employing as said tanning-active substance a carboxylic acid carrying at least one of an ester, urethane or amide group. Advantageously the agent has at least two carboxyl groups per molecule and a molecular weight of about 170 to 30,000, preferably 310 to 10,000. The products are softer and better through-tanned and there is maximum utilization of chromium, thereby minimizing the waste disposal problem.
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