PURPOSE: To obtain a new crystalline polypropylene, having specific physical poperties and excellent in rigidity and heat resistance by polymerizing propylene in the presence of a catalyst composed of a solid containing Mg, Ti, a halogen and an electron donative compound, an opganoaluminum compound, an organosilicon compound and an olefin.
CONSTITUTION: This crystalline polypropylene is obtained by polymerizing propylene in the presence of a catalyst component for polymerizing an α-olefin prepared by bringing (A) a solid component consisting essentially of Mg, Ti, a halogen and an electron donative compound into contact with (D) an olefin in the presence of (B) an organoaluminum compound and (C) an organosilicon compound expressed by formula I {R1 is cyclic substituent group, etc., containing ether or thioether bond in the ring; R2 is 1-10C hydrocarbon, etc.; R3 is methyl or ethyl; (x) is l or 2; (y) is 0 or 1; (z) is 2 or 3; [(x)+(y)+(z)] is 4}. This polypropylene has 5000-1000000 weight-average molecular weight (Mw) and the Mw and isotactic pentad fraction (IPF) satisfying the relationship expressed by formula II and is excellent in rigidity and heat resistance.
KANAZAWA SEIZABURO
ISHIHARA TAKESHI
TAKI NORIYUKI
UEKI SATOSHI
MORI HIRONORI
