PROPYLENE POLYMER COMPOSITION AND ORIENTED FILM MADE THEREFROM

摘要

The present invention provides a propylene polymer composition for producing a biaxially oriented film, comprising propylene random copolymer and propylene homopolymer; wherein the propylene random copolymer is a copolymer of propylene and ethylene, optionally comprising one or more alpha-olefins of C 4 -C 10 ; the propylene polymer composition has an overall isotacticity index, as determined by nuclear magnetic resonance method, of greater than or equal to 96.5%, and an ethylene content of greater than 0.3 wt%; and wherein, the melt flow rate of the propylene random copolymer is lower than that of the propylene homopolymer. The biaxially oriented polypropylene film produced by the propylene polymer composition of the present invention exhibits excellent physical properties, and has, in the absence of any stiffening agent, relatively higher modulus and stiffness. Moreover, the process for producing the biaxially oriented polypropylene film is featured with a good film-forming stability and a high film-forming stretching speed.