Making soft foam-faced, hard plastic component especially suitable for vehicle cladding concealing airbag, employs physical foaming agent e.g. inert gas or microcapsules

摘要

The surface layer is foamed using a physical propellant or foaming agent. An independent claim is included for the corresponding component. A further claim is included for use of a mold as described to make the component. Preferred features: The substrate is made first. The second material, i.e. the foam, is brought together under back pressure with the first, in a mold. The pressure is then reduced, especially to atmospheric pressure. The pressure is produced by a gas, which is subsequently blown off, to reduce the pressure. In a variant, the pressure is reduced by enlarging the molding cavity. Reduction is sudden. Wall thickness of the foam varies. Onto its surface a decorative material is applied. This is introduced in sheet form into the molding cavity, pressing it into its final position during the foaming process. It may be introduced preformed, at least locally. A flexible decorative material is employed, brought to final shape during foaming. Its formation is accompanied by pressure reduction. The decorative material is made as a sprayed skin and introduced into the mold. It is alternatively sprayed in the mold, and subsequently foamed at the rear. The propellant is an inert gas, especially CO 2 or N 2, and/or expansive microcapsules are employed. Microcapsules are mixed into the second material in a proportion of 0.5-20 wt%. The surface layer is compressed during or after completion of foaming, improving the surface structure of the foam. The surface layer is produced in a mold and then reduced in volume by a closure motion. The surface layer is expanded on completion of foaming, optionally by opening the mold to enlarge it. Further variants of the process based on the foregoing principles are elaborated. The mold used, has provision for expansion and/or contraction and/or slide(s), permitting operation as described. Inlets and outlets for gas and/or vacuum are provided. A microporous mold surface is employed for venting and/or vacuum production. In the mold, sliding and/or rotating components produce the required movements.