| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a propylene-ethylene block copolymer while reducing gels and fisheyes, without forming a polymer lamp and attached polymer, in a good state of fluidity. SOLUTION: This method for producing the propylene-ethylene block copolymer comprises continuously carrying out the first-stage and the second-stage polymerizations in the presence of a catalyst comprising the following components (A) and (B), and adding the following component (C) to the position higher than 50% of a fluidized bed for the second-stage polymerization, and a vapor phase-circulating system of the polymerization vessel so that the activity may become 0.3-0.95 time as much as that at the time when the component (C) is not added: (A) a solid catalyst component consisting essentially of Ti, Mg, a halogen and an electron donor; (B) an organoaluminum compound; (C) an electron donative compound; (1) the first-stage polymerization: a step for polymerizing propylene in liquid propylene or in a vapor phase state to provide a crystalline propylene polymer; and (2) the second stage polymerization: a step for polymerizing a mixture of the propylene and ethylene in a vapor phase state to provide a gummy copolymer.
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