GB572071A - Improvements in and relating to the metallisation of non-conductive fabrics and fibrous materials - Google Patents

Abstract

572,071. Metallizing non-conductive fabrics. CALLENDER-SUCHY DEVELOPMENTS, Ltd., and SUCHY, C. T. Feb. 29, 1944, No. 3712. [Class 41] In order to ensure the perfect adhesion of metal coatings on non-conductive fabrics and fibrous or porous materials such as paper, felt, asbestos, unglazed ceramic ware, and leather, the internal structure of the material is rendered conductive, whilst leaving the external surface non-conductive, and the metal plated on to the conductive internal structure beneath the surface. Where copper is the coating metal, a preliminary flash with copper cyanide can be given. A noble metal can be plated on to the copper. The material is, if necessary, initially degreased with trichlorethylene, hot-washed, and rinsed. It is then immersed in a 2-3 g.p.l. solution of stannous chloride, and washed, and then impregnated in a solution of ammoniacal silver hydroxide to which is added a reducing sugar solution immediately before use. Details of preparation of these solutions are given in the Specification. Agitation is resorted to during the impregnating process which lasts 20-30 minutes, and if necessary a second impregnation may be resorted to. The material is then washed, dried, and brushed to remove metallic silver particles from the surface, and then transferred to the electrolytic bath. Since moisture is absorbed in the Tatter, it is desirable to interrupt the electrolysis and dry the material thoroughly, the deposit being then polished to close all.pores in the coating and prevent further ingress of moisture during completion of the process. The initial deposit is effected at ¢ amp./dm' and 1¢-2 volts, the voltage being later increased to 4-6 and amperage to 1, accompanied by heat and agitation.