| 摘要 |
PURPOSE:To obtain an ethylene/alpha-olefin copolymer having no tendency toward decreasing in strength properties, which is characteristic of a linear low-density polyethylene, and having a wide MW distribution and excellent processability, by specifying its physical properties. CONSTITUTION:A copolymer of ethylene with 0.5-40wt.% 3-18C alpha-olefin, having a melt flow rate ratio >=35 and a melt expansion ratio <=1.35 can be obtained by the following process. Namely, ethylene and 3-18C alpha-olefins (e.g., those fed through lines 2, 3 and 4) are copolymerized together at a pressure >=400 bar in the presence of a Ziegler catalyst (poured into monomer lines by pumps 15, 16 and 17) in a reaction system (e.g., reactor 14) comprising at least two reaction zones so that the temperatures in the respective reaction zones may fall in the range of 130-350 deg.C and that the temperature difference between the reaction zones and the ratio between the amounts of the copolymers formed in the respective reaction zones may satisfy specified conditions. |
