Motor vehicle interior panel manufacture involves molding thermoplastic substrate in first tool, enlarging tool cavity and injecting foamable elastomer onto substrate where outer skin is formed against cold tool surface

摘要

A first plastic material(20) is injected into a first tool cavity(16) to form a molded substrate section of the final panel. A mixture of a thermoplastic elastomer and blowing agent heated under pressure in an injection molding machine is injected into a larger, second tool cavity which contains the substrate molding and molds a cushioning section onto the substrate. The mixture expands when there is no pressure acting on it and a smooth outer skin forms on the mixture as it meets a relatively cold tool surface. The outer skin of the foamed cushioning section forms after contact with a cooled tool surface. Substrates are molded in relatively rigid thermoplastic plastics. The mixture of thermoplastic elastomer and blowing agent is supplied in pellet form. The first tool cavity is formed by two tool parts(12,14) which move relative to each other and in their closed position form the shape of the initial substrate. A second tool cavity is created by removal of the second tool part and adding a third while the substrate remains in the cavity formed by the first tool part. Independent claims are included for the following: (1) a tool(10) for molding an interior panel for a motor vehicle which comprises a first injection molding tool with a first part(12) having an injection point(18) and a second part(14) which together form a cavity(16) for molding a substrate and a second tool formed by the first tool part, the molded substrate and a third tool part, the latter having an injection inlet for a polymer mixture forming the skinned cushioning section of the panel; (2) a motor vehicle interior panel construction comprising a substrate and a cushioned cover part with a smooth outer skin enclosing an expanded core and the thermoplastic elastomer and blowing agent mixture forming the skin and core is melted under pressure in an injection molding machine.