POLYPROPYLENE COMPOSITION FOR CABLE INSULATION Russian patent published in 2025 - IPC C08L23/14 H01B3/44 C08K5/09 C08K5/103 C08K5/521 

FIELD: chemistry.

SUBSTANCE: group of inventions relates to a flexible polypropylene composition, to a cable comprising an insulating layer including said polypropylene composition, and to use of said polypropylene composition as cable insulation for medium and high voltage cables. Described is a polypropylene composition suitable for cable insulation, which includes: (A) from 90.0 to 99.999999 wt. % of the total amount of the polypropylene composition of the propylene copolymer and comonomer links selected from ethylene and alpha-olefins containing from 4 to 12 carbon atoms, where total amount of comonomer links, determined by quantitative ¹³C{¹H} NMR spectroscopy, ranges from 10.0 to 16.0 wt. % of total number of monomer links in polypropylene composition, where the copolymer of propylene and comonomer units selected from ethylene and alpha-olefins containing from 4 to 12 carbon atoms is a heterophasic propylene copolymer, which includes a matrix phase and an elastomeric phase dispersed in said matrix phase; and (B) an alpha-nucleating agent selected from a group consisting of (i) salts of monocarboxylic acids and polycarboxylic acids, (ii) dibenzylidene sorbitol, C₁-C₈-alkyl-substituted dibenzylidene sorbitol derivatives or substituted nonite derivatives, and (iii) diesters salts of phosphoric acid, (iv) a vinylcycloalkane polymer and a vinylalkane polymer, and (v) mixtures thereof. Polypropylene composition has a total amount of a cold xylene soluble (CXS) fraction determined according to ISO 16152, which ranges from 25.0 to 50.0 wt. %. of the total weight of the polypropylene composition, where the amount of comonomer links, determined by quantitative ¹³C{¹H} NMR spectroscopy, is at least 23.0 wt. % of total amount of monomer links in cold xylene soluble (CXS) fraction, melt flow index MFI₂ ranging from 0.5 to 5.0 g/10 min, determined according to ISO 1133 at 230 °C and load of 2.16 kg, and a flexural modulus of not more than 470 MPa, determined according to ISO 178, method A (three-point bending test), on samples with dimensions of 80 mm × 10 mm × 4 mm.

EFFECT: providing a polypropylene composition having a balance of properties such as high flexibility, good mechanical strength, good impact properties and high crystallization and melting temperatures, which is suitable for use in cable insulation; cables comprising an insulating layer including a polypropylene composition according to the invention have high electric strength, which can be expressed in the form of an alpha parameter of Weibull distribution and a beta parameter of Weibull distribution.

15 cl, 6 tbl, 6 ex