Embossing leather

摘要

In embossing and decorating leather, a surface of the leather, e.g. the grain surface, is coated and slightly impregnated with a paraffin or a wax, and a pattern is then impressed on the surface by an embossing device, such as a roller operated mechanically or by hand, heated to a temperature between 200 and 650 DEG C., e.g. between 250 and 650 DEG C. During embossing of the leather, it is preferably backed by an elastic or resilient support. The paraffin or wax may have a melting point between 50 and 70 DEG C. Specified paraffins are: tetracosane, pentacosane, tricontane and hentricontane. A suitable wax is beeswax. The paraffin or wax may be applied to the surface of the leather in the form of an aqueous emulsion containing between 5 and 15%, e.g. 10%, by weight, of the paraffin or wax and, if desired a small amount, e.g. 1.2%, of an emulsifier. Between 2 and 20 grams of a 10% emulsion may be applied per square metre of the surface of the leather. In order to prevent the paraffin or wax penetrating too deeply and too quickly into the leather, its surface may be pre-treated with an aqueous dispersion containing between 0.5 and 2.0%, e.g. 100%, by weight, of one or more than one of the substances: egg albumen, blood albumen, casein, e.g. acidic milk casein, and a non-thermoplastic albuminoid condensation product. Between 3 and 30 grams of a 1.0% dispersion may be applied per square metre of the surface of the leather. Additional decorative effects may be obtained by embossing leather dyed with a heat-changeable dye.