# US 11,078,312 B2 · Crosslinkable polymer composition and cable with advantageous electrical properties

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- Number: US 11,078,312 B2
- Document ID: US11078312B2
- Status: Granted
- Kind: B2
- Application number: 13/509,268
- Filed: 2010-11-03
- Published: 2013-01-03
- Granted: 2021-08-03
- Earliest claimed: 2009-11-11
- Assignees: Borealis AG
- Applicants: Annika Smedberg; Birgitta Kallstrand; Ulf Nilsson; Per-Ola Hagstrand; Villgot Englund; Gustavo Dominguez; Carl-Olof Olsson; Liu Rongsheng; Marc Jeroense
- Inventors: Annika Smedberg; Birgitta Kallstrand; Ulf Nilsson; Per-Ola Hagstrand; Villgot Englund; Gustavo Dominguez; Carl-Olof Olsson; Liu Rongsheng; Marc Jeroense
- Web page: https://patentgrep.com/patent/US11078312B2

## CPC

- C08F 210/02: Ethene
- C08K 5/14: Peroxides
- C08L 23/00: Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L 23/06: Polyethylene
- H01B 3/441: {from alkenes}
- C08F 110/02: Ethene
- C08F 210/16: Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
- C08L 2203/20: use in electrical or conductive gadgets
- C08L 2207/066: LDPE (radical process)
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})

## Abstract

A cross-linked polymer composition includes a cross-linked polyolefin. Peroxide in an amount of less than 35 mmol —O—O—/kg polymer composition may be included in the polymer composition prior to crosslinking the polyolefin. Suitable polyolefins that can be cross-linked in the polymer composition include an unsaturated LDPE homopolymer and an unsaturated LDPE copolymer of ethylene with one or more comonomers. Such unsaturated LDPE polymer can contain vinyl groups, and the total amount of vinyl groups present in the unsaturated LDPE can be higher than 0.05/1000 carbon atoms. The cross-linked polymer composition can be used, for example, in producing a cross-linkable and cross-linked article such as a cross-linkable and cross-linked direct current (DC) or other type of power cable.

## Claims

### Claim 1

A crosslinked DC power cable which comprises a conductor which is surrounded by at least an inner semi conductive layer comprising a first semiconductive composition, an insulation layer consisting of a polymer composition that has been crosslinked, and an outer semiconductive layer comprising a second semiconductive composition, in that order,
wherein the polymer composition of said insulation layer consists of, prior to crosslinking, a polyolefin, an antioxidant, a peroxide and a scorch retarder, wherein said peroxide is present in an amount of 10.0 to 28 mmol —O—O—/kg polymer composition, and
wherein the polyolefin is, prior to crosslinking, an unsaturated LDPE copolymer of ethylene with 1,7-octadiene, and
wherein the unsaturated LDPE copolymer contains vinyl groups and the total amount of vinyl groups present in the unsaturated LDPE is higher than 0.54/1000 carbon atoms and 0.82/1000 carbon atoms or less,
wherein the polymer composition has an electrical conductivity of 45 fS/m or less, and
wherein the peroxide is dicumylperoxide,
wherein the antioxidant is 4,4′-thiobis(2-tertbutyl-5-methylphenol),
wherein the scorch retarder is 2,4-diphenyl-4-methyl-1-pentene,
wherein the amount of antioxidant is 0.08 wt %,
wherein the amount of the scorch retarder is from 0.05 wt % to 0.18 wt % relative to the total amount of the polymer composition.

### Claim 2 (depends on 1)

The crosslinked DC power cable according to claim 1, wherein the polymer composition has an electrical conductivity of 40 fS/m or less.

### Claim 3 (depends on 1)

The crosslinked DC power cable according to claim 1, wherein the polymer composition has an electrical conductivity of 0.5 to 35 fS/m.

### Claim 4 (depends on 1)

The crosslinked DC power cable according to claim 1, wherein the polymer composition has a PENT (Pennsylvania Notch Test) life time of 800 hours or more, when measured according to PENT test under load at 2 MPa and at ageing temperature of 70° C.

### Claim 5 (depends on 1)

The crosslinked DC power cable according to claim 1, wherein the polymer composition has a Stress at Break at 70° C. of 12.0 MPa or more, or at −10° C. of 30.0 MPa or more.

### Claim 6 (depends on 1)

The crosslinked DC power cable according to claim 1, wherein the polymer composition has a Strain at break (%) at 70° C. of 450% or more, or at −10° C. of 400% or more.

### Claim 7 (depends on 1)

The crosslinked DC power cable according to claim 1 wherein the polyolefin comprises a total amount of carbon-carbon double bonds/1000 carbon atoms of more than 0.4/1000 carbon atoms.

### Claim 8 (depends on 1)

The crosslinked DC power cable as claimed in claim 1, wherein the scorch retarder is present in the polymer composition of said insulation layer prior to crosslinking.