| 摘要 |
Ethylene polymer composition comprises two ethylene polymers with defined melt flow indices and has a defined molecular weight distribution, melt flow index and dyanmic viscosity and is produced using at least two reactors with continuous hydrogen supply, where the ratio between the partial pressures of ethylene and hydrogen in the first reactor is different from that in the other reactors and the quotient of these two ratios is more than 20. Ethylene polymer composition comprises: (a) 30-70 wt.% of an ethylene polymer (I) having a melt flow index MI2, measured at 190degreesC under a 2.16 kg load, of 5-1000 g/10 minutes, where (I) optionally contains up to 5 wt.% of an alpha-olefin or diene having 4-18 carbon atoms; and (b) 30-70 wt.% of an ethylene polymer (II) having a melt flow index MI5, measured at 190degreesC under a 5 kg load, of 0.01-2 g/10 minutes, where (I) contains 0.5-20 wt.% of an alpha-olefin or diene having 4-8 carbon atoms. The ratio of the melt flow indices is 500-50000. The composition has a molecular weight distribution (Mw/Mn) of 5-70, a MI5 of 0.1-10 g/10 minutes and a dynamic viscosity (eta), expressed in dPa.s and measured at 190degreesC and a shear rate of 100 s-1, that statisfies the following mathematical relationship: 0.625 at least (log (177470/MI5) - log eta)/(2 - log (2.53 x MI5)) The composition is produced using at least two reactors with continuous hydrogen supply, where the ratio between the partial pressures of ethylene and hydrogen in the first reactor is different from that in the other reactors and the quotient of these two ratios is more than 20. |
