POLYETHYLENE FOR PIPES Russian patent published in 2019 - IPC C08F2/00 C08F210/02 C08F210/16 C08L23/08 F16L9/12 

FIELD: chemistry.

SUBSTANCE: present invention provides a method of producing multimodal polyethylene, involving: (i) polymerisation of ethylene and optionally α-olefin comonomer at a first polymerisation step to produce a first ethylene polymer; and (ii) polymerising ethylene and optionally α-olefin comonomer in the presence of said first ethylene polymer at a second polymerisation step, in which the first and second polymerisation steps are carried out in the presence of a non-degraded metallocene polymerisation catalyst and each polymerisation step provides at least 5 wt. % multimodal polyethylene, and multimodal polyethylene has a multimodal molecular weight distribution, molecular weight of at least 50,000 g/mol and bulk density of at least 250 g/dm³, and in which solution of non-carried metallocene catalyst in solvent is used.

EFFECT: present invention also discloses multimodal polyethylene, a method of producing a pipe, which includes obtaining multimodal polyethylene and extruding multimodal polyethylene to produce a pipe, and a pipe made using said method.

60 cl, 3 tbl, 4 dwg