| 摘要 |
1,126,823. Tanning leather. FARBENFABRIKEN BAYER A. G. Feb. 10, 1966 [Feb. 10, 1965], No. 5945/66. Heading C6C. A process for the rapid tanning of leather comprises acidifying the pelts (e. g. cow) with an acid and a salt, pre-tanning, without a liquor, with 5-15%, referred to the pelt weight, of a pre-tanning agent comprising an auxiliary tannin and/or sulphite waste liquor and optionally an exchange tannin, optionally rinsing and finally tanning with or without a liquor, with a vegetable and/or a synthetic tannin. The auxiliary tannin may be a naphthalene sulphonic acid/formaldehyde condensation product having an acid number of at least 30 and containing 5-20% water soluble neutral salts. The acid number of the auxiliary tannin may be adjusted before, during or after the tannin is added to the pelts. The exchange resin may be a #-naphthalene-sulphonie acid/ dihydroxy-diphenyl sulphone/formaldehyde condensation product, a phenol sulphonic acid/urea/ formaldehyde condensation product, a #-naphthalene sulphonic acid/chlorophenol/formaldehyde condensation product, or a naphthalene-sulphonic acid/ pyrocatechol /formaldehyde condensation product. The final tanning agents may be chestnut extract, mimosa extract, valonia extract, myrobalam extract, sulphited quebracho extract, sulphonated fish oil and quebrocho extract. The leathers may be fat liquored. |
