| 摘要 |
The present invention relates to uncompounded particulate metallocene-produced polyethylene having a multimodal molecular weight distribution, said particulate polyethylene having a particle size distribution, the particle size distribution being measured by obtaining at least 4 fractions by sieving (M1, M2, M3, M4,...), one faction containing the upper particle size, one fraction containing the lower particle size, and the other fractions containing particle sizes in between the upper and lower sizes, whereby a set of Mw values is obtained, which set comprises the Mw of each fraction (M1, M2, M3, M4,...),with Mw being the weight-average molecular weight, a set of Mn values is obtained, which set comprises the Mn of each fraction (M1, M2, M3, M4), with Mn being the number-average molecular weight, a mean value and standard deviation value are obtained for the Mw set, and a mean value and standard deviation value are obtained for the Mn set, and characterized in that the ratio between the standard deviation value of the Mw set and the mean value of the Mw set is equal to or less than 0.15; and the ratio between the standard deviation value of the Mn set and the mean value of the Mn set is equal to or less than 0.15. The present invention also relates to a process for preparing said uncompounded particulate metallocene-produced polyethylene. The present invention also relates to an apparatus comprising at least three loop reactors connected in series, configured for preparing the uncompounded particulate metallocene-produced polyethylene according to the invention, and a process for preparing said polyethylene using said apparatus. |
