| 摘要 |
PURPOSE:To obtain a block copolymer having a small amount of formed low crystalline part, slightly causing aggregation and anchorage, having improved low-temperature impact resistance, by carrying out block copolymerization by specific two processes in the presence of a catalyst obtained by combining three components. CONSTITUTION:A propylene-ethylene block copolymer is obtained by polymerization of the following two processes in the presence of catalyst obtained by combining three components of (A) a solid composition comprising magnesium, titanium and a halogen as essential components, (B) an organoaluminum compound and, (C) an amine compound having steric hindrance. (i) Propylene alone or a mixture of propylene/ethylene is polymerized at one stage or multiple stages to form 60-95wt% based on the final amount of polymer of a propylene polymer or a propylene-ethylene copolymer containing <=7wt% ethylene. (ii) A mixture of propylene/ethylene is polymerized at one stage or multiple stages to form a propylene-ethylene copolymer containing 20-100wt% ethylene.
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