| 摘要 |
<p>1511017 Tanning of hides BAYER AG 15 May 1975 [18 May 1974 (2)] 20585/75 Heading C6C Leather is chrome-tanned by a process comprising pre-tanning a pickled dehaired hide with a chromium (III) salt, followed by full tanning with a chromium (III) salt, an acid-binding agent and at least 1À6 mols. per mol. of Cr 2 O 3 in the chromium (III) salt used for full tanning, of an aliphatic C 4-6 dicarboxylic acid and/or an aromatic dicarboxylic and/or tricaboxylic acid containing from 8 to 13 carbon atoms and/or a salt thereof, the total weight of Cr 2 O 3 offered amounting to 1À2 to 2% of the weight of the hide, and tanning being carried out with a weight of tanning mixture of up to 100% of the weight of the hide, up to a final pH value of the tanning solution of at least 3À6. The carboxylic acid may be succinc, glutaric, adipic, phthalic and/or isophthalic acid. The acid-binding agent may be dolomite, an alkali metal carbonate or bicarbonate, alkaline earth metal carbonate or bicarbonate, magnesium oxide or sodium sulphite. Tanning mixtures of the inventionicomprise a chromium (III) salt, and acid-binding agent and at least 1À6 mols per mol of Cr 2 O 3 of an aliphatic C 4-6 dicarboxylic acid and/or an aromatic dicarboxylic and/or tricarboxylic acid having from 8 to 13 carbon atoms and/or a salt thereof.</p> |
