Sheet-like stamped parts based on plastic, and process for the production thereof

摘要

The present invention relates to a sheet-like stamped part which has a thickness of 60-600 mu m, preferably 80-400 mu m. It is composed of a polypropylene alloy having a polypropylene content of greater than 80% by weight, preferably greater than 85% by weight, and comprising an isotactic propylene homopolymer having an MFI 230/2.16 of 3-50 g/ 10 min, preferably 5-30 g/10 min, and finely divided, highly porous, amorphous silicic acid having a mean particle size of 0.2-10 mu m, preferably 0.5-5 mu m, in an amount of 0.4-10% by weight, preferably 0.5-7% by weight, and optionally processing assistants and/or other additives. The invention furthermore relates to a process for the production of sheet-like stamped parts of the above composition, in which the polypropylene-containing polymer film web emerging from the flat film extruder is cooled and conditioned by rewarming to temperatures of 5-60 DEG C, preferably 10-50 DEG C, below the melting point of the polypropylene homopolymer employed, is then recooled, optionally aftertreated, and stamped.