CABLE INSULATION COMPOSITION Russian patent published in 2021 - IPC H01B3/44 C08L23/06 C08L23/08 C08F210/02 G02B6/44 

FIELD: cables.

SUBSTANCE: invention relates to a composition which can be used to produce external cable sheaths, including power cables, communication cables, as well as to a cable made from said composition, to a method of producing the composition, as well as to use of the catalyst in the method of producing the composition. Composition cable insulation comprises a multimodal olefin copolymer which has a density of from 0.935 to 0.960 g/cm³ and a MFR₂ (melt flow rate) of 2.2 to 10.0 g/10 min. Density is measured in accordance with ISO 1183-1:2004 on a sample molded under pressure, made in accordance with EN ISO 1872-2. MFR₂ is measured in accordance with ISO 1133-1 at 190 °C. Composition has ESCR (resistance to environmental cracking) of at least 2000 hours and cable shrinkage of 0.70 % or less. Resistance to environmental cracking is measured in accordance with method B of IEC 60811-406. Cable shrinkage is measured on 400 mm sample after 24 hours at 100 °C according to formula [(L_before−L_after)/L_before]×100 %, where L is length. Method of producing a cable insulation composition is that a multimodal olefin copolymer is obtained by polymerisation, which is carried out in the presence of a catalyst on a MgCl₂ substrate. Method of producing catalyst comprises (a) first obtaining particles of a solid adduct of MgCl₂×mROH adduct, where R is a linear or branched alkyl group with 1–12 carbon atoms, m equals 0 to 6. At step (b) solid carrier particles are treated with group 13 metal compound. Further, solid carrier particles are in contact with an organic compound of formula (I) below, in which R₁-R₅ are identical or different and can be hydrogen, a linear or branched C₁-C₈-alkyl group or C₃-C₈-alkylene group, or two or more of R₁-R₅ can form ring, two oxygen-containing rings are separately saturated, or partially unsaturated, or unsaturated, or isomers of the organic compound of formula (I) or mixtures thereof. Then step (c) is carried out, where particles of the solid support are treated with group 4–6 transition metal compound. Then, solid catalyst component is reduced.

EFFECT: invention allows reducing cable shrinkage, improving mechanical properties of the composition, improving manufacturability while maintaining hardness and resistance to cracking under the effect of environment.

15 cl, 4 tbl, 9 ex