| 摘要 |
PURPOSE: To obtain a crystalline polypropylene excellent in rigidity and heat resistance by polymerizing propylene in the presence of a catalyst component prepared by bringing a specified solid component into contact with an olefin in the presence of an organoaluminum compound and a specified organosilicon compound. CONSTITUTION: This polypropylene is prepared by polymerizing an olefin in the presence of anα-olefin polymerization catalyst component prepared by bringing a solid component essentially consisting of a metal compound, Mg, Ti, a halogen and an electron-donating compound into contact with an olefin in the presence of an organoaluminum compound and an organosilicon compound represented by the formula: R<1> Si(OR<2> )x (OR<3> )y (R<1> is a 5-7 C alicylic hydrocarbon group; R<2> is 2-ethoxyethyl or the like; R<3> is methyl or the like; x and y are each 1 or 2; and x+y=3) and satisfies the relationship (ω0 is the frequency at which the storage modulus is equal to the loss modulus; G0 is the modulus atω0 ; and IPF is the isotactic pentad fration in C-NMR measurements).
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