| 摘要 |
PURPOSE:To obtain a block copolymer excellent in the balance among variaus properties such as impact resistance, rigidity and processability continuously with a good productivity, by using a stereoregular polymerization catalyst, a specified manner of polymerization and specified compounds. CONSTITUTION:Polymerization is carried out by using a catalyst prepared by combining a titanium-containing solid catalyst component (A) with an organoaluminum compound (B), using at least three polymerization vessels connected and using the following two steps: step 1 of continuously performing polymerization by feeding a propylene-based monomer of an ethylene/(ethylene + propylene) ratio of 0-5wt% to at least two polymerization vessels connected in series to produce 60-95wt% portion of the total polymer, and step 2 of producing 5-40wt% portion of the total polymer, by continuously adding a glycol ether (C) in an amount corresponding to C/(Ti in component A) ratio of 0.01-1.0(mol/atom) to the polymerization reaction mixture obtained in step 1 and continuously feeding a monomer of an ethylene/(ethylene + propylene) of 0.01-1.0(mol/atom) to at least one polymerization vessel to produce 5-40wt% portion of the total polymer.
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