| 摘要 |
PURPOSE:To obtain a block copolymer having improved low-temperature impact resistance, by polymerizing only propylene by the use of a highly active catalyst to give a stereospecific polypropylene, followed by carrying out propylene-alpha- olefin copolymerization. CONSTITUTION:For example, a TiCl3 composition, (C2H5)2AlCl, propylene, hydrogen, and an inert solvent (e.g., n-hexane, etc.) are fed to the first-stage polymerizers wherein the three polymerizes 1 are connected in series. In the first polymerization zone, polymerization of polypropylene is continuously carried out in >=4,000 catalytic efficiency, and propylene is released by the flash drum 2. The polymerization mixture is processed by the centrifugal separator 3 to give a propylene polymer having <=70wt% solvent content (dry base), which is dried by the airborne dryer 4 and the fluidized bed dryer 6 into <=3.5wt% solvent content. Propylene is added to the propylene polymer in the transferring chamber 7, and polymerization is carried out in a weight ratio of propylene/alpha-olefin=5-90/95- 10 (weight ratio) by the horizontal type polymerizaer 8 and in a ratio of the propylene polymerization process/copolymerization process=95-5/5-95. |
