GB932673A - Improvements in or relating to methods of manufacturing articles bearing an engraved design of a decorative or informative nature - Google Patents

Abstract

932,673. Ornamenting. GENERAL ELEC. TRIC CO. Ltd., and J. H. W. SMITH. Sept. 28, 1961 [Dec. 12, 1960], No. 42708/60. Class 93. An article bearing an engraved design of a decorative or informative nature is made by adhering a metal foil to a non-metallic backing member, treating it to remove part of the foil in order to define the design, the method including the steps of forming a pattern in a resist on the outer face of the foil so that all but said part of the foil is covered by the resist, chemically removing said part of the foil, coating with paint at least part of the surface of the backing member which is exposed when said part of the foil is removed, and removing any surplus paint from the outer face of the remainder of the foil after the paint has dried. As described, a copper foil is stuck to a rectangular sheet of laminated paper board impregnated with a phenolic resin, and the exposed surface is sprayed with a resist designed to harden on exposure to ultra-violet light. A photographic positive of the desired design is prepared and placed on the resist coating and the assembly subjected to ultraviolet radiation. The unhardened parts of the resist are removed by a vapour degreaser e.g. trichloroethylene, and the unprotected parts of the copper foil etched with ferric chloride. The remainder of the resist is removed by rubbing with a cloth soaked in trichloroethylene, and the parts of the backing member exposed by the etching is coated with paint e.g. a cellulose paint. Any paint which overlaps on to the surface of the copper foil is removed, and the treated sheet immersed in a solution of ammonium hydrosulphide to form a protective coating of copper sulphide on the foil. Other treatments include treatment with selenious acid, or electroplating. The sheet is then treated e.g. by spraying with a transparent lacquer.