摘要:
Horny substances are removed from hides, pelts or skins of dead animals by treating the hides, pelts or skins in aqueous liquor with one or more compounds of the formula I or their corresponding alkali metal or alkaline earth metal salts or ammonium or phosphonium salts, the variables being defined as follows: R1 is selected from hydrogen and C1-C12-alkyl, unsubstituted or substituted by one or more S—H or O—H groups; X1 to X4 are identical or different and are selected from hydrogen, C1-C4-alkyl, O—H, S—H and N—HR2, R2 is hydrogen or C1-C12-alkyl or a C1-C4-Alkyl-C═O group, at least one radical X1 to X4 being S—H when R1 contains at least one sulfur atom and at least two radicals X1 to X4 being S—H when R1 contains no sulfur atom.
摘要:
Tanning agents can be prepared by reacting at least one aldehyde of formula I, with at least one further identical or different aldehyde of formula I, where Z is a single chemical bond, unsubstituted or substituted C1-C12-alkylene, unsubstituted or substituted C5-C12-cycloalkylene or unsubstituted or substituted C6-C14-arylene, the reaction being carried out in the presence of an acidic catalyst and in the presence of at least one further carbonyl compound of formula II where R1 to R4, independently of one another, are hydrogen, unsubstituted or substituted C1-C12-alkyl, unsubstituted or substituted C3-C12-cycloalkyl, unsubstituted or substituted C7-C13-aralkyl or unsubstituted or substituted C6-C14-aryl, with the proviso that, where Z is a single chemical bond or a radical without a-hydrogen atoms, at least one further aldehyde of the formula I, in which Z contains α-hydrogen atoms, or at least one further carbonyl compound of formula II is present.
摘要:
The invention relates to a method for removing horn substances from animal skin. The method is characterized in that animal skins are treated in an aqueous bath containing between 0.05 and 5 wt. %, in relation to the weight of the salt, of at least one compound of general formula I or the corresponding alkali metallic salts or alkaline-earth metallic salts thereof or ammonium or phosphonium salts. The aqueous bath also comprises at least one compound which catalyses the hydrolysis of peptide compounds
摘要:
A semifinished leather product is produced from an animal hide by pretanning with the use of a chromium-free tanning agent and of a clay mineral which, after stirring for 30 minutes in water at 50° C. at a circumferential rotor speed of from 5 to 25 m/s, has a number average particle diameter of less than 2 μm or a bimodal particle size distribution with a first, finely divided fraction whose number average particle diameter is less than 0.5 μm and a second, coarser fraction whose number average particle diameter is less than 5 μm, determined in each case by the method according to ISO 13320-1, by combined laser light diffraction and light scattering, a proportion of the first, finely divided fraction being from 10 to 90% by weight, and drying of the pretanned animal hide to a water content of from 5 to 45%, based on the total weight of the semifinished leather product.
摘要:
Mixtures of (A) from 55 to 65 mol % of erythro-dithiol of formula erythro-IV: and (B) from 35 to 45 mol % of threo-dithiol of formula threo-IV or threo-IV′: and their corresponding alkali metal salts and ammonium salts, are useful for treating animal hides.