| 摘要 |
PURPOSE:To obtain the title novel copolymer satisfying specified requirements, capable of giving films which are excellent in transparency and blocking resistance and significantly small in the change of the transparency before and after heat treatment, by copolymerization between ethylene and a specific alpha- olefin. CONSTITUTION:The objective copolymer, a copolymer from ethylene and 3-4C alpha-olefin, having the following characteristics: (1) melt flow rate determined in accordance with the ASTM D 1238E: 0.01-100g/10min; (2) density determined in accordance with the ASTM D 1505: 0.88-0.94g/cm<3>; (3) alpha-olefin unit content: 1-25wt.%; and (4) giving two peaks for the DSC melting peak pattern when raised in temperature, using a DSC from 10 deg.C to 200 deg.C at a rate of 10 deg.C/min, of a sheet 0.5mm thick produced by melting the present copolymer at 200 deg.C followed by annealing to 50 deg.C at a rate of 0.31 deg.C/min to effect crystallization, and satisfying the relationship when the ratio of the height of the peak on higher temperature side to that of lower temperature side and the density of the present copolymer are expressed as Hh/HI and d, respectively. |
