GB565065A - Improvements in or relating to the treatment of hides or skins - Google Patents

Abstract

565,065. Tanning. UNITED SHOE MACHINERY CORPORATION. Jan. 16, 1943, No. 840. Convention date, Jan. 17, 1942. [Class 76] Skins and hides are tanned or preserved by dehydrating and permeating with a non- aqueous solution of a water-soluble tanning or other preservative material (which may, however, contain a small proportion of water), substantially removing the non-aqueous solvent, and then activating the tanning material. Dehydration of the skins is effected by immersing two or three times in a water-miscible organic solvent, such as acetone, or by forcing the solvent through the skin. After drying, the skin is immersed in the solvent solution of the tanning material or the solution is drawn through the skin by means of vacuum. After removal of the solvent, the tanning material may be activated by immersing the skin in an aqueous liquor. In an example, quebracho extract dissolved in methyl alcohol is used as the tanning agent and is activated by immersing the skin in water or aqueous quebracho solution. Another example describes the use of hemlock bark in methyl alcohol solution, and a third example a strong aqueous solution of chromium sulphate to which is added glycol monomethyl ether and methyl alcohol, followed by treatment of the skin with aqueous ammonia. The application of the invention to retanning (e.g. of chrome-tanned skins) is described. Extracts of oak, sumach leaves and wattle bark, and salts of aluminium and iron (e.g. the chlorides) and chromium (e.g. chloride and nitrate) are other tanning agents mentioned. The Specification as open to inspection under Sect. 91 comprises also the treatment of skins with chromic chloride in methyl alcohol solution or with ferric chloride dissolved in a mixture of absolute alcohol and mesityl oxide, in either case followed by immersion in an absolute alcohol solution of ammonia, and also tanning with chromic nitrate in methyl alcohol solution, followed by immersion in an acetone solution of ammonia. Tanning of dehydrated skins by treatment with a methyl alcohol solution of a resin, for example, the resin known under the Trade Mark " Vinsol," is also described. This subject -matter does not appear in the Specification as accepted.