PROCESS FOR PRODUCING POLYOLEFIN

摘要

Process for the production of an oriented polyolefm film using multi- component polymer compositions. One polymer component comprises an isotactic propylene homopolymer produced by the polymerization of propylene with a Ziegler- Natta catalyst. A secondary component is a Ziegler-Natta polymerized ethylene- propylene random copolymer or a metallocene-polymerized ethylene-propylene random copolymer produced by the polymerization of propylene and ethylene in the presence of a metallocene polymerization catalyst. The Ziegler-Natta polymerized copolymer is produced by the polymerization of ethylene and propylene in the presence of a Ziegler- Natta catalyst and contains no more than 0.5 wt.% ethylene and has a xylene solubles content of at least 2 wt.%. The primary and secondary polymer components are mixed together to provide a blend in which, when the secondary component is a Ziegler-Natta polypropylene, is present in an amount within the range of 5-25 wt.% and the secondary polymer component is a metallocene-based copolymer present in an amount of less than 5 wt.%. After mixing the two polymer components together, the mixture is extruded and the formed into a biaxially oriented film.