GB1353355A - Metalcontaining fibrous material - Google Patents

Abstract

1353355 Coating fibres with metals C DAVIDOFF 19 April 1971 [15 April 1970] 26173/71 Heading C7F [Also in Divisions B6 and D1] In discrete areas of a flexible fibrous sheet material woven from fibre units or yarns composed of electrically non-conductive and magnetically non-responsive continuous filaments, the filaments throughout the thickness of the material are individually coated with a substantially uniform film of electrically conductive or magnetically responsive metal. The material may be formed by selectively etching away the metal coating from the filaments of a material whose filaments are all metal coated. Alternatively the material may be formed by selective deposition of the metal. The filaments may be composed of glass, silk or synthetic organic polymers, copolymers and mixed polymers. Examples of suitable materials are given. The metal coating may be of silver, gold, platinum, palladium, copper, aluminium, nickel, cobalt, iron, titanium, molybdenum, chromium, tungsten, lead, tin, zinc, cadmium, manganese, antimony, germanium, indium, rhenium, ruthenium, rhodium, selenium, rare earth metals and mixtures and alloys of two or more of these. The filaments may be metallized by deposition from aqueous or organic solutions of metal salts or other reducible metal compounds. Alternatively the filaments may be "gas plated" wherein one or a mixture of heat-decomposable gaseous compounds of the selected metal or metals is thermally decomposed in situ on the surfaces of the fibres. The etching may be by means of dilute nitric acid (for silver, copper, cobalt, iron and nickel), hot or concentrated sulphuric acid (for silver, copper, cobalt, aluminium and palladium) and aqua regia (for gold and platinum). Sodium or potassium cyanide may also be used together with hydrogen peroxide, m-nitrobenzoic acid, and sodium m-nitrobenzenesulphonate as additives. Mild electrolytic action may be used to aid attack of the etchant. The selective attack may be accomplished by directing a jet of etchant only at areas where attack is desired or by use of a mask. The sheet may be clamped between apertured metal plates which permit attack only through the apertures. The inner surfaces of the plates may be coated with resilient material to act as a gasket to prevent seepage of the etchant. As an alternative to selective removal of metal from a metallized sheet, a non-metallized sheet may be selectively metallized by using the techniques described above for overall metallization but with the use of a suitable mask e.g. the apertured metal plates. The products of the invention are stated to be suitable for use as capacitance circuits, antennas, dipoles, magnetically responsive elements, identification labelling, leads for connecting medical instruments (e.g. electrocardiac machines to the human body, electrical connections and recording tape.)