A polypropylene for use in the production of a biaxially oriented film and biaxially oriented film obtained therefrom by stretching

摘要

Disclosed are a polypropylene for use in production of a biaxially oriented film, said polypropylene being obtained by carrying out polymerization by the use of an olefin-polymerizing catalyst consisting of: (A) a solid catalyst component containing magnesium, titanium, halogen and electron donative compound as essential components, (B) an organoaluminum compound, and (C) at least two electron donative compounds including electron donative compound ( alpha ) and electron donative compound ( beta ), provided that the pentad stereoirregularity index (mmrr/mmmm) of 105 DEG C xylene-insoluble fraction of a homopolypropyelene obtained by carrying out polymerization by the use of electron donative compound ( alpha ) together with the above-mentioned solid catalyst component (A) and organoaluminum compound (B) satisfies the following condition: <DF>0 ≤ mmrr/mmmm ≤ 0.0068 </DF> and the pentad stereoirregularity index (mmrr/mmmm) of 105 DEG C xylene-insoluble fraction of a homopolypropylene obtained by carrying out polymerization by the use of electron donative compound ( beta ) together with the above-mentioned solid catalyst component (A) and organoaluminum compound (B) satisfies the following condition: <DF>0.0068 < mmrr/mmmm ≤ 0.0320 </DF> and a biaxially oriented film obtained by subjecting the polypropylene to a stretching processing. <IMAGE>