HIGH-DENSITY POLYETHYLENE Russian patent published in 2011 - IPC C08J5/18 C08L23/06 C08F210/16 B29C47/00 

FIELD: chemistry.

SUBSTANCE: invention describes multimodal polyethylene which is suitable for use as a film, as well as a pipe. The polyethylene is characterised by density between 0.940 and 0.965 g/cm³, flow melt index l₂₁ between 4 and 20 dg/min. The polyethylene contains a low-molecular ethylene copolymer, having weight-average molecular weight between 5000 and 50000 amu, characterised by short-chain branching index between 2.5 and 4.5; and high-molecular ethylene copolymer, having weight-average molecular weight between 60000 and 800000 amu, characterised by short-chain branching index between 2 and 2.5. The invention also describes multimodal polyethylene, where the weight ratio of the high-molecular ethylene copolymer in terms of the overall multimodal composition is between 0.3 and 0.7. The ratio of branching indices of the low- and high-molecular ethylene copolymers is between 1.2 and 6.0.

EFFECT: balance of short-chain branches makes multimodal polyethylene suitable for use in making films, pipes, in fields using centrifugal moulding and blow moulding.

23 cl, 5 dwg, 6 tbl, 4 ex