| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for stably and efficiently producing an excellent propylene/(ethylene-α-olefin) block copolymer which has high content of a copolymer component (CP) and in which occurrence of stickiness or bleed-out is restrained. SOLUTION: The method for producing the propylene-based block copolymer by consecutive polymerization comprises: a first step of producing a crystalline propylene polymer component by using a supported metallocene catalyst; and a second step of producing the copolymer component (CP) of ethylene with at least one comonomer selected fromα-olefins having 4-20 carbon atoms by a vapor-phase polymerization method. The following important matters of (i) to (iii) are satisfied in the method for producing the propylene/(ethylene-α-olefin) block copolymer, that is, (i) the average particle diameter of the polymer particles after the first step is completed and before the second step is started is 500-1,200μm, (ii) the ratio of the copolymer component (CP) to the total mass of the propylene/(ethylene-α-olefin) block copolymer is 30-95 mass%, and (iii) the content ofα-olefin in the copolymer component (CP) is 1-50 mass%. COPYRIGHT: (C)2009,JPO&INPIT
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