Production of molded parts, e.g. sandwich panels with a polyurethane foam core, involves foaming polymer in a closed, vented mold with a flexible, gas-permeable membrane on the inner surface of the mold

摘要

A method for the production of molded parts (1) by filling an expanding/foaming polymer (4) into a mold (2), closing the mould and foaming the polymer with removal of displaced or formed gas through vent holes (8) in the mold, involves covering an internal surface of the mold (2) with a flexible, gas-permeable membrane (9), at least around the vent holes (8), before closing the mold. An independent claim is included for a membrane (9) with at least one gas-permeable layer of thermoplastic elastomer, for use in this method.