BIMODAL POLYETHYLENE FOR BLOW-MOULDING APPLICATIONS.

摘要

The invention relates to a process for the polymerisation of ethylene to produce a polyethylene resin in at least two slurry loop reactors connected to each other in series, the resin having a bimodal molecular weight distribution, a molecular weight distribution MWD of at least 7.0, an HLMI of from 1 to 100 g/10min, and a density of from 0.935 to 0.960 g/cm, wherein in one reactor 30 to 47 wt% based on the total weight of the polyethylene resin of a high molecular weight (HMW) polyethylene fraction is produced having an HL275 of from 0.05 to 1.8 g/10min (the equivalent of HLMI of from 0.01 to 0.56 g/10min), a density of from 0.925 to 0.942 g/cm and a MWD of at least 5.0, and in the other reactor a low molecular weight (LMW) polyethylene fraction is produced an HLMI of from 10 to 1500 g/10 min and a density of from 0.960 to 0.975 g/cm, in the presence of a Ziegler-Natta catalyst system.