| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing effectively a propylene-based block copolymer excellent in flexibility and impact resistance by copolymerizing ethylene or a 4-20Cα-olefin and propylene which have well-balanced reactivity with each other between the monomers in the presence of a metallocene catalyst supported on a carrier to provide a copolymer having a high molecular weight. SOLUTION: This method for producing a propylene-based block copolymer includes: a former process for producing a propylene homopolymer component in the presence of a metallocene catalyst supported on a carrier; and a later process for producing a copolymer component by copolymerizing propylene with at least one comonomer selected from the group consisting of ethylene and 4-20Cα-olefins by a gas phase method, wherein the later process is performed under a condition where each of a reactivity ratio (r1) of ethylene or a 4-20Cα-olefin and a reactivity ratio (r2) of propylene is in the range of 0.5 to 2.8. COPYRIGHT: (C)2008,JPO&INPIT
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