Composite vehicle interior component manufacture involves injection of molten plastic with dissolved blowing agent into a tool and setting process pressure and temperature to expand blowing gas inside tool

摘要

A blowing agent is metered into a liquid plastic(24) outside a molding tool cavity(14) and injected onto the rear face(22) of a decorative layer(18) prelocated in the cavity. Process parameters are set so that the blowing agent dissolves as a single phase in the plastic outside the tool and expands to form cells(26) after injection into the tool cavity. Blowing agent is added to the plastic in an extruder which melts the plastic and conveys it to an injection tool. Expansion of the blowing agent is effected by reducing pressure and/or temperature. The blowing agent temperature outside the tool cavity(14) is above its critical temperature and pressure above its critical pressure. Temperature and pressure inside the tool cavity are at levels which keep the blowing agent in a gaseous state. Soft and hard plastics may be injected one after the other to produce a twin layer backing(24). An independent claim is included for a composite product manufactured by the process which comprises a decorative layer(18) with visible face(20) and non-visible rear face(22) covered by an injected plastic layer.