Increasing adhesion between metal coatings and polymer substrates - by depositing a first metal layer, followed by an interlayer contg. the first metal and a second metal, and then the second metal alone

摘要

A process for coating polymeric substrates (I) with metal comprises: (a) depositing a first layer of metal (II) on the substrate; (b) depositing a layer of a second metal (III) together with metal (II) on the first layer; and (c) depositing a layer of metal (III) on the intermediate layer. Also claimed are silver-coated polycarbonate and nylon substrates, with a first layer of chromium on the polymer, a metallic interlayer consisting of Cr and Ag deposited together (pref. contg. 2-33% Cr), and an outer layer of Ag. USE/ADVANTAGE - Metal- (esp. Ag)-coated plastics as above are useful esp. for the prodn. of car headlamp reflectors; silver is more reflective to visible light than Al and less reflective to UV. The invention provides a process for increasing the adhesion between silver and polymeric substrates; the process can be carried out at relatively high pressure, e.g. 10-4 mbar, suitable for vapour deposition on the industrial scale.