Abstract: Process for treating polyolefin discharged from an olefin polymerization reactor which comprises steps of discharging from a polymerisation reactor a slurry comprising polyolefin and diluent; submitting said slurry to a pressure release such that the diluent is evaporated and a polyolefin/gas mixture is formed; discharging said polyolefin/gas mixture into a collecting vessel; controlling a level of settled polyolefin in the collecting vessel; discontinuously transferring the polyolefin/gas mixture in the collecting vessel into a concentrating vessel; and discharging said concentrator vessel in such a way that said polyolefin/gas mixture is transferred into the hydrocarbon purge bin. Embodiments also comprise the use of two interconnected concentrator vessels and the optimized recovery of the diluent from the purge bin.

Abstract: An ethylene polymer composition having a density of at least 950 kg/m3, a fluidity index MI5 of 0.05 to 2 g/10 min and a content of alpha-olefin containing from 4 to 10 carbon atoms of from 0.15 to 1 mole %, containing from 53 to 63% by weight based on the total weight of the composition of an ethylene polymer fraction (A) having a fluidity index MI2 of at least 100 g/10 min a density of at least 969 kg/m3 and a molecular weight distribution Mw/Mn greater than 4, and from 37 to 47% by weight based on the total weight of the composition of a copolymer fraction (B) of ethylene and from 0.32 to 2.7 mole % of at least one alpha-olefin containing from 4 to 10 carbon atoms, a fluidity index MI5 to 0.001 to 0.5 g/10 min, a density of no more than 930 kg/m3 and a molecular weight distribution Mw/Mn greater than 4, wherein the ratio of the MI2 of fraction (A) to the MI5 of fraction (B) is greater than 20,000.

Abstract: Polyethylene-based composition for which the standard density, measured at 23° C. according to ASTM Standard D 792, is greater than 940 kg/m3 and which comprises talc in an amount of less than 1 part per 100 parts by weight of polyethylene. The composition is preferably in the form of extruded granules. It exhibits a markedly improved creep resistance. Process for the manufacture of shaped articles and articles shaped from the composition, in particular pipe couplings and pipes intended for the transportation of pressurized fluids.