Method for manufacturing a metal-elastomer composite seal with at least one zinc electroplated metal sheet between two elastomer layers

摘要

Process for fabricating a composite elastomer-metal gasket for high pressure applications comprises: (a) coating an electro-galvanised steel sheet on both faces with a thin polymer-based film; (b) cutting and shaping the coated galvanised steel sheet into the required form to act as the reinforcing core layer of the gasket; (c) coating both faces of the reinforcing layer with a layer of elastomer, esp. by coating with a liq. elastomer compsn. that is not fully polymerised; and (d) curing the elastomer by thermal treatment. Pref. the step of coating with a thin film of polymer is carried out in-line directly after electroplating of the steel plate. The coating is pref. formed by applying and drying a liq. coating compsn. contg. the polymer in suspension and at least 0.1 wt.% phosphoric acid. The coating liq. may also contain at least 0.5 wt.% chromic acid (expressed as CrO3). The polymer is pref. an acrylic-based polymer. The coating film is pref. applied at a rate of 0.4-0.6 (0.5) g/m<2> and contains more than 1% phosphate cpds. (expressed as PO4) and opt. more than 1% cpds. based on Cr in the +VI oxidn. state (expressed as Cr). <IMAGE>