Sumitomo Chemical Company, Limited

Koji Mizunuma

Toshio Sasaki

Kazuki Wakamatsu

Takeshi Ebara

Junichi Kimura

Yoichi Obata

A process for producing an olefin polymer using a catalyst in which (A) is a solid catalyst component which includes magnesium, titanium, halogen and an electron donative compound as essential constituents; (B) is an organoaluminum component; and (C) is at least two electron donative compounds (&agr;) and (&bgr;), wherein the pentad stereoregularity of a xylene insoluble fraction of a homopolyproylene is 0<mmrr/mmmm&lE;0.0068 when electron donative compound (&agr;) is used in combination with (A) and (B), and the pentad stereoregularity of a xylene insoluble fraction homoproplyene of a is 0.0068<mmrr/mmmm &lE;0.0320 when electron donative compound (&bgr;) is used in combination with (A) and (B). A polypropylene produced in the process can be used to obtain a biaxially oriented film. (A) and (B). A polypropylene produced in the process can be used to obtain a biaxially oriented film.

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

A catalyst system for polymerizing olefins is obtainable from (A) a solid component containing (A) magnesium, titanium and halogen and an electron donative compound which is an ether or ester; (B) an organoaluminum compound, and (C) at least two electron donative compounds, including an (.alpha.) and (.beta.) compound, wherein the total amount (C) compounds is 0.01 to 1 mole per mole of (B).

Process for producing olefin polymers, olefin-polymerizing catalyst and

An .alpha.-olefin polymer well balanced between stiffness, stickiness, processability, etc., which intrinsic viscosity [.eta.] is in the range of from 0.5 to 10 and which 20.degree. C. xylene-soluble fraction (CXS) content (% by weight) and 105.degree. C. xylene-insoluble fraction (XIS) content (% by weight) satisfy a condition of XIS.ltoreq.70.00-3.64CXS, provided that CXS is not smaller than 0 and not greater than 15; a specified .alpha.-olefin polymerizing catalyst for producing the polymer; a process for producing the polymer using the specified .alpha.-olefin polymerizing catalyst; a polypropylene for use in the production of a biaxially oriented film excellent in stretchability and satisfying the conditions (1)-(3) mentioned below; and a biaxially oriented film excellent in stiffness and dimensional stability obtained by stretching the polypropylene:

Growing community of inventors

Kisarazu, Japan

Koji Mizunuma