US 12,258,465 B2
Polyethylene composition for high pressure resistant pipes with improved homogeneity
Yi Liu, Linz (AT); Victor Sumerin, Provoo (FI); and Qizheng Dou, Linz (AT)
Assigned to BOREALIS AG, Vienna (AT)
Appl. No. 17/287,579
Filed by BOREALIS AG, Vienna (AT)
PCT Filed Oct. 22, 2019, PCT No. PCT/EP2019/078712
§ 371(c)(1), (2) Date Apr. 22, 2021,
PCT Pub. No. WO2020/088987, PCT Pub. Date May 7, 2020.
Claims priority of application No. 18203693 (EP), filed on Oct. 31, 2018.
Prior Publication US 2021/0317290 A1, Oct. 14, 2021
Int. Cl. C08L 23/08 (2006.01); C08F 2/00 (2006.01); C08F 4/02 (2006.01); C08F 210/16 (2006.01); C08L 23/0807 (2025.01)
CPC C08L 23/0815 (2013.01) [C08F 2/001 (2013.01); C08F 4/022 (2013.01); C08F 210/16 (2013.01); C08L 2203/18 (2013.01); C08L 2205/025 (2013.01); C08L 2314/02 (2013.01)] 15 Claims
 
1. A polyethylene composition comprising:
a base resin, which is a polymeric part of the polyethylene composition without fillers, having a density of from 953.0 kg/m3 to 960.0 kg/m3, determined according to ISO 1183, wherein
the polyethylene composition has a melt flow rate MFR21 (190° C., 21.16 kg), of from 1.0 to 7.5 g/10 min, determined according to ISO 1133, a complex viscosity at a frequency of 0.05 rad/s eta0.05 of from 750 kPa·s to 1900 kPa's, determined according to ISO 6721-1 and ISO 6721-10, a white spot rating of 3.0 to 12.0, determined according to ISO 18553, after a single compounding step in a twin screw extruder at an extruder temperature before die plate of 200° C. to 300° C. and a specific energy input SEI of 200 kwh/ton to 350 kWh/ton, a weight average molecular weight Mw of 300 kg/mol to 600 kg/mol, determined by GPC, a molecular weight distribution Mw/Mn of from 30 to 65, and a tensile modulus of 1200 MPa to 2000 MPa, determined according to ISO 527-2:1993.