Method for preparing silicone rubber/fluoroelastomer integrated rubber article

Abstract

A rubber article is manufactured by heat curing a heat-curable silicone rubber composition filled with untreated fumed silica to form a substrate, applying a primer composition comprising a fluoroalkylene or fluoropolyether compound having at least one alkenyl radical and at least one hydrolyzable silyl radical onto the substrate surface, and disposing a heat-curable perfluoropolyether elastomer composition thereon and curing the composition for integration. The integrally molded article has characteristics of both silicone rubber and fluoroelastomer.

Description

BRIEF DESCRIPTION OF THE DRAWING

The only figure, FIG. 1 is a schematic cross-sectional view of an integrally molded article for test manufactured in Examples.

Claims

1. A method for preparing a rubber article, comprising the steps of: heat curing a substrate-forming composition (a) comprising 100 parts by weight of a heat-curable silicone rubber composition and 0.5 to 50 parts by weight of untreated fumed silica to form a substrate,applying a primer composition (b) comprising a fluoroalkylene or fluoropolyether compound having at least one alkenyl radical and at least one hydrolyzable silyl radical in the molecule onto a surface of the substrate, anddisposing thereon a heat-curable perfluoropolyether elastomer composition (c) and curing the composition for integration.

2. The method of claim 1, wherein the silicone rubber substrate is formed by molding and curing the substrate-forming composition (a) comprising a heat-curable silicone rubber composition and untreated fumed silica, said silicone rubber composition comprising a diorganopolysiloxane having the average compositional formula (I): (R11)aSiO(4-a)/2  (I)

3. The method of claim 1 or 2, wherein in said primer composition (b), the fluoroalkylene or fluoropolyether compound having at least one alkenyl radical and at least one hydrolyzable silyl radical in the molecule has the general formula (1): A-(C2H4)q—(X)p—Rf′—(X′)p—(C2H4)q—B  (1)

4. The method of claim 1, wherein said heat-curable perfluoropolyether elastomer composition (c) comprises a polymer having at least two alkenyl radicals in the molecule and a perfluoropolyether structure in the backbone, a compound having at least two SiH radicals in the molecule, and a platinum group catalyst.