VERBESSERTE PROPYLENPOLYMERE FÜR ORIENTIERTE FILME

摘要

This invention relates generally to crystalline polypropylene polymers and methods for their production. Specifically, this invention relates to crystalline polypropylene polymer compositions comprising both propylene homopolymers and propylene copolymers. The compositions are prepared using metallocene catalyst systems comprising at least two metallocenes in a polymerization process that involves the sequential or parallel polymerization of propylene homopolymers and copolymers using propylene with a small amount of comonomer, preferably ethylene. The resulting polymers are excellent for use in the production of biaxially oriented films. Films prepared with these propylene polymers have a significantly broader processability range and can be evenly stretched at lower temperature compared to films prepared from traditional polypropylene polymers.