Patent ID: 6670027
Filing Date: 2003-12-30
Classification: B29C,B29K,C08J,C08L,Y10S,Y10T

Abstract:
A uniaxially oriented polypropylene film formed from a film-forming material which comprises a polypropylene resin material consisting of 40 to 95% by weight of crystalline polypropylene, and 60 to 5% by weight of propylene-&agr;-olefin copolymer dispersed as particles in the crystalline polypropylene, wherein the crystalline polypropylene is a propylene homopolymer or a propylene-&agr;-olefin copolymer having propylene unit content of 90% or more by weight,the propylene-&agr;-olefin copolymer dispersed as particles contains 20-80% by weight of propylene polymerization units, the polypropylene resin material is obtained by continuously polymerizing the crystralline polypropylene and the propylene-&agr;-olefin copolymer dispersed as particles by multi-step polymerization, and the particles of the copolymer have an aspect ratio (L/D) of mean dispersed particle length (L) to mean dispersed particle diameter along the film thickness direction (D) of 100 or more in a cross section of the film along the MD direction, and the mean dispersed particle diameter of 0.10 &mgr;m or less.