POLYOLEFIN COMPOSITION FOR PIPELINE SYSTEMS AND SHEETS Russian patent published in 2012 - IPC C08L23/08 C08L23/10 C08L23/14 F16L9/12 

FIELD: chemistry.

SUBSTANCE: composition contains 1) 10-60 wt % propylene and hexene-1 copolymer, where said copolymer contains 0.2-10 wt % repeating units obtained from hexene-1, 2) 10-85 wt % propylene polymer selected from a propylene homopolymer and a propylene polymer with 0.1-10 wt % α-olefin selected from ethylene, C₄-C₁₀-α-olefin, except hexene-1, and mixture thereof, and 3) 5-30 wt % copolymer of ethylene and C₃-C₁₀-α-olefin and optionally a diene, having ethylene content from 15 to 60 wt %. The propylene polymer is insoluble in xylene at room temperature in amount higher than 85% and has polydispersity index from 3 to 20. The disclosed polyolefin composition has modulus of elasticity in flexure higher than 1200 MPa, Izod impact strength at 20°C from 5 to 20 kJ/m² and burst pressure resistance higher than 3000 hours.

EFFECT: pipeline systems made from said composition have optimum balance of mechanical properties.

6 cl, 1 tbl