POLYETHYLENE COMPOSITION FOR PRESSURE PIPES WITH IMPROVED HOMOGENEITY Russian patent published in 2022 - IPC C08F210/16 C08F4/651 C08L23/06 F16L9/12 

FIELD: polymers.

SUBSTANCE: invention relates to polyethylene compositions with improved homogeneity, suitable for pressure pipes. Proposed is a polyethylene composition containing a base resin with a density of 952.0 kg/m³ to 960.0 kg/m³, as defined in accordance with ISO 1183, wherein the polyethylene composition has a melt flow rate MFR₂₁ (190°C, 21.16 kg) of 1.0 to 7.5 g/10 minutes, as defined in accordance with ISO 1133; a complex viscosity at frequency of 0.05 rad/s eta_0.05 of 750 kPa*s to 1,900 kPa*s, as defined in accordance with ISO 6721-1 and ISO 6721-10; a white spot index of 12.0 or less, as defined in accordance with ISO 18553; and a modulus of elongation of 1,200 MPa or greater, as defined in accordance with ISO 527-2:1993. Also proposed are a polyethylene composition produced using a multi-stage method, a method for producing said polyethylene composition, a product constituting pipes or pipe fittings containing said polyethylene compositions, and an application of said polyethylene composition for producing pipes or pipe fittings.

EFFECT: proposed polyethylene composition is suitable for manufacturing pressure pipes and exhibits an improved balance of manufacturability, mechanical properties, tensile and sag properties, along with slow fracture propagation and high homogeneity.

15 cl, 5 tbl