ETHYLENE COPOLYMER, COMPOSITION CONTAINING ETHYLENE COPOLYMER, METHOD OF PRODUCING COPOLYMER, USE OF COPOLYMER AND TUBE Russian patent published in 2012 - IPC C08L23/04 C08L23/08 C08F297/08 F16L9/12 

FIELD: chemistry.

SUBSTANCE: multimodal copolymer of ethylene and one or more alpha-olefins containing 4-10 carbon atoms is characterised by density of 937-950 kg/m³, flow melt index STR₅ of 0.5-2.0 g/10 min, flow melt index STR₂ of 0.2-1.0 g/10 min, and shear thinning index IUVS₂._7/210 of 0.3-20. The multimodal copolymer contains 30-70 wt % low-molecular weight ethylene polymer, selected from an ethylene homopolymer and a copolymer of ethylene and one or more alpha-olefins containing 4-10 carbon atoms, and is characterised by weight-average molecular weight of 5000-100000 g/mol and density of 960-977 kg/m³, and 30-70 wt % copolymer of high-molecular weight ethylene and one or more alpha-olefins containing 4-10 carbon atoms, and is characterised by average molecular weight of 100000-1000000 g/mol and density of 890-929 kg/m³.

EFFECT: compositions are flexible; tubes made therefrom can be easily bent or coiled into a ring; the tubes are characterised by sufficient mechanical strength, which enables their use under pressure.

15 cl, 1 dwg, 3 tbl, 5 ex