POLYETHYLENE COMPOSITION FOR OUTER CABLE SHEATH AND OUTER INSULATION FOR STEEL PIPES Russian patent published in 2018 - IPC C08L23/06 C08L23/08 C08K3/04 

FIELD: chemistry.

SUBSTANCE: invention relates to polymer composition for producing an insulating layer of pipes or a power cable. Composition comprises 80–95 % by weight of a mixture of ethylene (A) polymers and 5–20 % by weight of a mixture of ethylene polymers (B). Mixture (A) contains component (1), which is an ethylene homopolymer with a melt flow index (MFR_{2.16 kg/190 °C}) from 0.3 to 200 g/10 min, density from 0.955 to 0.970 g/cm³ and a crystallinity of 60–75 % and a component (2) which is a copolymer of ethylene and 1-hexene or a copolymer of ethylene and 1-butene with a melt flow index (MFR_{2.16 kg/190 °C}) from 0.01 to 0.3 g/10 min, density from 0.925 to 0.940 g/cm³ and with a crystallinity of 40–55 %, wherein the ratio of components (1) and (2), in weight %: is 30÷55:45÷70. Mixture (B) contains, as component (3), an ethylene/hexene-1 copolymer or an ethylene-butene-1 and hexene-1 copolymer having a melt flow index (MFR_{2.16 kg/190 °C}) from 0.3 to 5.0 g/10 min, a density of from 0.919 to 0.935 g/cm³ and a crystallinity of 20–50 %, component (4), which is an amorphous alpha-olefin elastomer having a melt flow index (MFR_{2.16 kg/190 °C}) from 3.7 to 5.0 g/10 min, a density of from 0.865 to 0.879 g/cm³ and a crystallinity of 2.5–16 %, and component (5), which is a technical carbon. And mass ratio of components (3):(4):(5) in mixture (B) is 0.01÷89.99:0.01÷89.99:10÷40.

EFFECT: polymer composition of invention has good processability and electrical conductivity.

1 cl, 5 tbl