GB762997A - Improvements in or relating to the fat-liquoring of leather - Google Patents

Abstract

Leather is fat liquored and rendered water-repellant by treatment with a complex compound of the Werner type in which a trivalent nuclear chromium atom is co-ordinated with a carboxylic acido group having at least 10 carbon atoms. Such complexes may be prepared by reacting carboxylic acids having at least 10 carbon atoms with basic salts of trivalent chromium having a basicity not greater than 50 per cent. The basic chromium salts may be formed by reducing a hexavalent chromium compound such as chromyl chloride or chromic oxide with an alcohol which may also function as a solvent for the reaction. The carboxylic acid may be acyclic, carbocyclic, saturated or unsaturated, acyclic acids being exemplified by capric, undecoic, lauric, tridecoic, myristic, pentadecoic, palmitic, margaric, stearic, nondecoic, and arachidic acids, olefinic carboxylic acids such as decylenic, myristelenic, palmitolenic and oleic, linoleic, linolenic, elaeostearic, clupanodonic acids and carboxylic acids having branched carbon chains in which the total number of carbon atoms in the chain is at least 9. The acids may be derived from coconut oil, cottonseed oil, soya bean oil, linseed oil, animal fats and oils and fish oils. Substituted fats and oils such as ethanol palmitamide and alpha-aminostearic acid may be also employed. Typical carbocyclic acids are alpha and beta-naphthoic acids, abietic acid and other aryl carboxylic acids. Preferred complexes are stearato chromic chloride, oleato chromic chloride, and abietato chromic chloride.