GB365338A - Improvements in or relating to the coating of leather and products obtainable thereby - Google Patents

Abstract

365,338. Costing leather. IMPERIAL CHEMICAL INDUSTRIES, Ltd., Millbank, London. Jan. 30, 1931, No. 3034. Convention date, Jan. 31, 1930. [Class 140.] Leather is coated with a cellulose derivative composition of low film-strength containing a wax; for example, cellulose nitrate or acetate, wax, a plasticizer, a solvent, and a diluent. Leather coated with this composition may be " boarded " to produce a grained finish. The amount of plasticizer used should be only the small amount necessary for the proper grinding and incorporation of the pigments. If large amounts of plasticizer are used, large amounts of wax and pigment must be used. By grinding the pigment in the wax, the plasticizer may be omitted. The ingredients may be ground in alcohol. The plasticizer may be dibutyl phthalate, castor oil, tricresyl phosphate, dibutyl tartrate, or any known plasticizer. Pigments such as zinc oxide, titanium oxide, chrome yellow or orange, and iron oxide may be used, or dyes such as nigrosine. A high ratio of inert material to binder is of advantage. The wax may be of vegetable, animal, mineral, or synthetic origin ; preferably a wax of high melting point such as carnauba, beeswax, candelilla, or montan wax, is used. While not generally desirable, a suitable natural or synthetic resin, e.g. shellac, may be added. Any solvent may be used, preferably with a quantity of diluent or thinner, such as alcohol. The composition may be applied by any method, preferably by spraying, the leather being stretched on a frame. When the leather is boarded, the film breaks at all points where stress is applied, and microscopic cracks are produced. Examples of compositions are given.