Process for producing multimodal polyethylene compositions

摘要

The invention deals with a process for producing a multimodal polyethylene composition. The process comprises the steps of: (i) introducing a first polyethylene resin (A) having a weight average molecular weight Mw of from 150 to 3000 kg/mol and MFR 5 of not more than 60 g/10 min and comprising from 10 to 90 % of an ultra-high molecular weight polyethylene (A-1) having viscosity average molecular weight of at least 700 kg/mol into a feed port of an extruder; (ii) introducing a second polyethylene resin (B) having MFR 5 of from 0.15 to 1.0 g/10 min and a density of equal to or more than 945 kg/m 3 to equal to or less than 970 kg/m 3 into a feed port of the extruder; (iii) melting and mixing the first polyethylene resin (A) and the second polyethylene resin (B) in the extruder to form a multimodal polyethylene composition; (iv) recovering the multimodal polyethylene composition from the extruder; and (v) cooling and solidifying the multimodal polyethylene composition, wherein the multimodal polyethylene composition has a melt flow rate MFR 5 (190°C, 5 kg) of at most 1.0 g/10 min and a density of equal to or more than 935 kg/m 3 to equal to or less than 965 kg/m 3 .