Semi-conductive polypropylene composition

Claims

1. A semiconducting composition comprising (A) from 25.0 to 67.5 wt.% of a first copolymer of propylene and comonomer units selected from ethylene and alpha-olefins with 4-12 carbon atoms, wherein the first copolymer (A) has melt flow index MFI2 from 2.0 to 6.0 g / 10 min, determined according to ISO 1133 at 230°C and 2.16 kg; the content of the soluble fraction (SF), determined by the CRYSTEX extraction crystallization method in the range from more than 25.0 to 50.0 wt.%, based on the total weight of the first copolymer (A); and total comonomer content from 7.5 to 20.0 wt.%, based on the total weight of the first copolymer (A), determined using FTIR spectroscopy calibrated quantitatively 13 C-NMR spectroscopy based on CRYSTEX extraction crystallization data; (B) from 5.0 to 50.0 wt.% of a second copolymer of propylene and comonomer units selected from ethylene and alpha-olefins with 4-12 carbon atoms, wherein the second copolymer (B) has melt flow index MFI2 of at least 2.0 g / 10 min, determined according to ISO 1133 at 230°C and 2.16 kg; the content of the soluble fraction (SF), determined by the CRYSTEX extraction crystallization method, in the range from 12.0 to 25.0 wt.%, based on the total weight of the second copolymer (B); and total comonomer content from 4.0 to 10.0 wt.% based on the total weight of the second copolymer (B), determined by FTIR spectroscopy, calibrated quantitative 13 C-NMR spectroscopy based on CRYSTEX extraction crystallization data; and (C) from 15.0 to 35.0 wt.% carbon black, where all mass quantities are calculated for the total mass of the semiconducting composition.

2. The semiconducting composition according to claim 1, in which the soluble fraction (SF) of the first copolymer (A) has the number of comonomer units determined using FTIR spectroscopy calibrated by quantitative 13 C-NMR spectroscopy, from 20.0 to 35.0 wt.% based on the total number of monomer units in the soluble fraction (SF) of the first copolymer (A) and / or intrinsic viscosity (IV(RF)), determined according to ISO 1628-3, in the range from 150 to 250 cm 3 / G.

3. The semiconducting composition according to claim 1 or 2, wherein the first copolymer (A) has one or more or all of the following properties: melting point Tm from 140 to 159°C, determined using differential scanning calorimetry (DSC) analysis according to ISO 11357 / part 3 / method C2; and / or crystallization temperature Tcr from 85 to 125°C, determined using DSC analysis according to ISO 11357 / part 3 / method C2; and / or the difference between the melting point and the crystallization temperature Tpl-Tcr from 20 to 70°C; and / or total intrinsic viscosity from 150 to 350 cm 3 / g, determined according to ISO 1628-3; and / or a flexural modulus of not more than 470 MPa, determined according to ISO 178 method A; and / or Charpy impact strength of a notched specimen at 23°C from 40 to 110 kJ / m 2 , determined according to ISO 179-1 / 1eA; and / or complex viscosity at a frequency of 100 rad / s eta* 100 рад / с from 750 to 950 Pa⋅s.

4. A semiconducting composition according to any one of claims 1 to 3, wherein the first copolymer (A) has been visbroken.

5. A semiconducting composition according to any one of paragraphs 1-4, in which the soluble fraction (SF) of the second copolymer (B) has the number of comonomer units determined using FTIR spectroscopy calibrated by quantitative 13C-NMR spectroscopy, in the range from 15.0 to 35.0 wt.% based on the total number of monomer units in the soluble fraction (SF) of the second copolymer (B) and / or intrinsic viscosity (IV(RF)), determined according to ISO 1628-3, in the range from 90 to 190 cm 3 / G.

6. A semiconducting composition according to any one of claims 1 to 5, wherein the second copolymer (B) has one or more or all of the following properties: melting point Tm from 130 to 150°C, determined using DSC analysis according to ISO 11357 / part 3 / method C2; and / or crystallization temperature Tcr from 80 to 120°C, determined using DSC analysis according to ISO 11357 / part 3 / method C2; and / or the difference between the melting point and the crystallization temperature Tpl-Tcr from 20 to 70°C; and / or total intrinsic viscosity from 100 to 250 cm 3 / g, determined according to ISO 1628-3; and / or a flexural modulus greater than 470 MPa, determined according to ISO 178 method A; and / or Charpy impact strength of a notched specimen at 23°C from 4.0 to 15.0 kJ / m 2 , determined according to ISO 179-1 / 1eA; and / or complex viscosity at a frequency of 100 rad / s eta* 100 рад / с from 500 to 700 Pa⋅s.

7. A semiconducting composition according to any one of claims 1 to 6, wherein the second copolymer (B) has been visbroken.

8. A semiconducting composition according to any one of claims 1 to 7, wherein the carbon black (C) has one or more or all of the following properties: a primary particle size of at least 5 nm, defined as the average particle diameter according to ASTM D3849-14, an iodine adsorption value of at least 10 mg / g, when determined according to ASTM D-1510-19; and / or oil absorption number (OAN) of at least 30 ml / 100 g when measured according to ASTM D2414-19.

9. A semiconducting composition according to any one of claims 1 to 8, free of a polyolefin functionalized with a mono- or polycarboxylic acid compound or a derivative of a mono- or polycarboxylic acid compound.

10. A semiconducting composition according to any one of claims 1 to 9, free from 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ).

11. A semiconducting composition according to any one of paragraphs 1-10, having one or more or all of the following properties: melt flow index MFR5 from 2.0 to 100 g / 10 min, determined according to ISO 1133 at 230°C and 5 kg; and / or melt flow index (MFI) 10 from 12 to 600 g / 10 min, determined according to ISO 1133 at 230°C and 10 kg; and / or density from 0.850 to 1.200 g / cm 3 , determined according to ISO 1183; and / or tensile strength from 10.0 to 25.0 MPa, determined at 23°C according to ISO 527-1; and / or relative elongation at break from 350 to 750%, determined at 23°C according to ISO 527-1.

12. A semiconducting composition according to any one of paragraphs 1-11, having a volume resistivity (VR) from 6.0 to 55.0 Ohm⋅cm.

13. An article comprising a semi-conductive composition according to any one of paragraphs 1-12.

14. The product according to item 13, which is a cable containing a semiconducting layer that includes a semiconducting composition.

15. Use of a semiconductive composition according to any of paragraphs 1-12 as an inner and / or outer semiconductive layer for medium voltage cables.