BIAXIALLY STRETCHED POLYPROPYLENE-BASED PLASTIC PRODUCTS, AND PROCESS FOR MAKING SUCH PRODUCTS

摘要

The invention relates to polypropylene-based plastic products, biaxially stretched below the melting point, wherein the plastic consists substantially of a mixture of 60-95 % by weight of a substantially crystalline propylene polymer and 5-40 % by weight of an ethylene-vinylalcohol copolymer, and to a process for making such products. According to the invention an ethylene-vinylalcohol copolymer is used having a melting point which is at most equal to that of the propylene polymer, preferably 0-20 K below the melting point of the propylene polymer. The invention provides biaxially stretched polypropylene products having an outstandingly good gas impermeability while retaining their good properties in respect of optical clarity, mechanical properties and simplicity of production.