BIMODAL POLYETHYLENE RESINS AND PIPES MADE THEREOF Russian patent published in 2021 - IPC C08F210/16 C08F8/00 C08L23/08 C08F10/02 F16L9/12 

FIELD: polymer materials.

SUBSTANCE: invention relates to an ethylene polymer for producing articles, in particular, thick-walled pipes of a large diameter, wherein settling or deflection may be a limiting factor. The ethylene polymer is characterised by density in the range from 0.94 g/cm³ to 0.96 g/cm³, HLMI (I₂₁) in the range from 4 to 20 g/10 min, Mw/Mn ratio from more than 18 to 38, zero shear viscosity (η₀) at 190°C in the range from 20,000 to 400,000 kPa×s, and a relaxation time (τ_η) at 190°C in the range from more than 825 to 3,000 s. Ethylene polymers can be produced by processing a resin with a wide molecular weight distribution, catalysed by a Ziegler-Natta catalyst, with peroxide. Also described are production articles, in particular, agricultural films, automobile parts, bottles, containers for chemical substances, sheets, bands, etc., and pipes produced of or containing such ethylene polymers.

EFFECT: combination of technological properties and physical properties required for production, in particular, of thick-walled pipes of a large diameter, wherein problems of settling or deflection may occur, additionally, pipes produced using the ethylene polymers are characterised by the operating time in chlorinated water at 90°C and 450 lb/sq. inch of at least 1,200 hours.

17 cl, 2 dwg, 3 tbl, 4 ex