| 摘要 |
PURPOSE:To produce the title copolymer excellent in rigidity and impact strength, by polymerizing propylene or a propylene/ethylene mixture in two stages in the presence of a specified catalyst. CONSTITUTION:A catalyst is obtained by combining a solid catalyst component obtained by contacting a solid component containing Ti, Mg and a halogen with a silicon compound of formula I (wherein R<1> is a branched hydrocarbon residue, R<2> is R<1> or a different hydrocarbon residue, R<3> is a hydrocarbon residue and 1<=n<=3) at -50-200 deg.C with an organoaluminum compound (e.g., trimethylaluminum) and an alkoxy compound of formula II (wherein M is a metal selected from among B, Al, C, Si, P, Ti and Zr, R<4-5> are each a 1-20C hydrocarbon residue, X is a halogen, x is a number of from 1 to the valence of the metal M and x+y+z= the valence of the metal M). Propylene or a propylene/ethylene mixture of an etylene content >=5wt% is polymerized in one or more stages to obtain 60-95wt% of the total weight polymer, and a propylene/ethylene mixture of an ethylene content of 20-100wt% is fed to the reaction system and polymerized to obtain 40-5wt% of the total weight of polymer.
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