| 摘要 |
PROBLEM TO BE SOLVED: To produce a relatively low stereospecific polypropylene, having a low content of an atactic component, excellent in processability and useful as a film, etc., by polymerizing propylene in the presence of a specific catalyst. SOLUTION: Propylene is polymerized in the presence of a catalyst comprising (A) a solid Ti catalyst component prepared by prepolymerizing an olefin in the presence of a solid Ti compound component obtained by bringing a solid Ti compound containing Mg, tetravalent Ti, a halogen and an electron donor into contact with an organoaluminum halide compound represented by formula I [R is a 1-10C saturated hydrocarbon; X is a halogen; (n) is O<(n)<3] and an organosilicon compound represented by formula II (R<1> to R<3> are each a 1-20C hydrocarbon) and an organoaluminum compound without any halogen atom, (B) an organoaluminum compound and (C) an organosilicon compound represented by formula III (R' is a 1-20C straight-chain hydrocarbon; R<5> is a 1-10C hydrocarbon) and/or ethyl silicate to afford a polypropylene. |
