| 摘要 |
PURPOSE:To obtain propylene block copolymer easily in markedly good energy efficiency, by polymerizing propylene by a specified polymerization process by using a catalyst comprising a transition metal catalyst and an organometallic compound. CONSTITUTION:A block copolymer of propylene is produced by substantially homopolymerizing propylene and then copolymerizing propylene with ethylene by using a catalyst comprising a transition metal catalyst and an organometallic compound. Said substantial homopolymerization of propylene is performed at a temperature <= the m.p. of polypropylene by bulk polymerization in which propylene itself is used as a liquid medium or by vapor phase polymerization in which (1) substantially no liquid medium is present, and (2) said copolymerization of propylene with ethylene is performed in the presence of a diene under conditions under which the block copolymer is substantially in a molten state when the polymerization of at least this part is completed, and conditions under which substantially no liquid medium is present.
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