Process for producing olefin polymers, olefin-polymerizing catalyst and polypropylene for biaxially oriented film produced with said catalyst.

摘要

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 compounds ( alpha ) and ( 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: 0 </= mmrr/mmmm </= 0.0068 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 ( alpha ) together with the above-mentioned solid catalyst component (A) and organoaluminum compound (B) satisfies the following condition: 0.0068 < mmrr/mmmm </= 0.0320; a process for producing an olefin polymer using the catalyst; a polypropylene for use in production of a biaxially oriented film, the polypropylene being obtained by carrying out polymerization by the use of the polymerizing catalyst wherein: (1) 23 DEG C decalin-soluble fraction content of the polypropylene is in the range of from 3.0 to 10.0% by weight, (2) the temperature at which the polypropylene shows a complex elastic modulus of 1.0 x 10<9> dynes/cm<2> when a vibration of 110 Hz is applied to the polypropylene is in the range of from 134 to 152 DEG C, and (3) melt flow rate (MFR) of the polypropylene at 230 DEG C is in the range of from 0.5 to 10.0 g/10 minutes; and a biaxially oriented film obtained by subjecting the polypropylene to a stretching processing.