Electric cable with improved thermoplastic insulating layer

Patent metadata

Field	Value
Publication number	US-10839978-B2
Application number	US-201716754916-A
Country	US
Kind code	B2
Filing date	Oct 12, 2017
Priority date	Oct 12, 2017
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

An electric cable for high-voltage applications is disclosed which comprises a core surrounded by an electrically insulating layer made of a composition based on a thermoplastic polymeric material charged with boron nitride powder in an amount up to 20 wt % with respect to the weight of the insulating composition, the boron nitride powder having a particle size distribution D50 up 0 to 15 μm. Such a cable has improved thermal conductivity property as well as good dielectric resistance and workability in particular through extrusion processes.

First claim

The invention claimed is:

1. An electric cable, comprising: a core surrounded by an electrically insulating layer comprising an insulating composition, wherein the insulating composition is based on a thermoplastic polymeric material charged with boron nitride powder in an amount of up to 20 wt % with respect to a total weight of the insulating composition, and the boron nitride powder has a particle size distribution D50 of up to 15 μm, wherein the thermoplastic polymer material is selected from the group consisting of: a copolymer (i) of propylene with an olefin co-monomer selected from the group consisting of ethylene and an α-olefin other than propylene, wherein the copolymer (i) has a melting point of at least 130° C. and a melting enthalpy of from 20 J/g to 90 J/g, a blend of the copolymer (i) with a copolymer (ii) of ethylene with an α-olefin, wherein the copolymer (ii) has a melting enthalpy of from 0 J/g to 120 J/g, and a blend of a propylene homopolymer with either the copolymer (i) or the copolymer (ii); and at least one of the copolymer (i) and the copolymer (ii) is a heterophasic copolymer.

2. The electric cable according to claim 1 , wherein the amount of the boron nitride powder is at least 10 wt % with respect to the total weight of the insulating composition.

3. The electric cable according to claim 1 , wherein the amount of the boron nitride powder is less than 20 wt % with respect to the total weight of the insulating composition.

4. The electric cable according to claim 1 , wherein the particle size distribution D50 of the boron nitride powder is up to 10 μm.

5. The electric cable according to claim 1 , wherein the particle size distribution D50 of the boron nitride powder is at least 0.1 μm.

6. The electric cable according to claim 1 , wherein boron nitride of the boron nitride powder has a hexagonal form.

7. The electric cable according to claim 6 , wherein boron nitride particles of the boron nitride powder are uncoated.

8. The electric cable according to claim 1 , wherein the boron nitride powder has a particle size distribution D100 of lower than 50 μm.

9. The electric cable according to claim 8 , wherein the boron nitride powder has a particle size distribution D100 of lower than 40 μm.

10. The electric cable according to claim 1 , wherein the thermoplastic polymeric material forming the electrically insulating layer comprises a dielectric fluid.

11. The electric cable according to claim 10 , wherein the dielectric fluid is a synthetic or mineral oil of low or high viscosity.

12. The electric cable according to claim 11 , wherein the dielectric fluid is a mineral oil, which is selected from the group consisting of a naphthenic oil, an aromatic oil, and a paraffinic oil.

13. The electric cable according to claim 1 , comprising an inner and/or an outer semiconductive layer made of a composition comprising a thermoplastic polymeric composition charged with a conductive filler and with boron nitride powder in an amount of up to 20 wt % with respect to a total weight of the thermoplastic polymeric composition, wherein the boron nitride powder has a particle size distribution D50 of up to 15 pm.

Assignees

• Prysmian Spa

Inventors

• Besson Romain
• Caimi Luigi
• Bareggi Alberto
• Ferrari Armando Michele
• Troia Ivan

Classifications

• H01B3/002 Primary

  Inhomogeneous material in general · CPC title

• C08K7/00

  Use of ingredients characterised by shape · CPC title

• H01B3/006 Primary

  Other inhomogeneous material · CPC title

• H01B3/441

  from alkenes · CPC title

• H01B9/027

  composed of semi-conducting layers · CPC title