# US 10,246,527 B2 · Polymer composition comprising a polyolefin produced in a high pressure process, a high pressure process and an article

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- Number: US 10,246,527 B2
- Document ID: US10246527B2
- Status: Granted
- Kind: B2
- Application number: 13/509,257
- Filed: 2010-11-03
- Published: 2012-11-15
- Granted: 2019-04-02
- Earliest claimed: 2009-11-11
- Assignees: Borealis AG
- Applicants: Ulf Nilsson; Annika Smedberg; Alfred Campus; Achim Blok; Bjorn Voigt
- Inventors: Ulf Nilsson; Annika Smedberg; Alfred Campus; Achim Blok; Bjorn Voigt
- Web page: https://patentgrep.com/patent/US10246527B2

## CPC

- C08F 10/00: Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
- H01B 3/441: {from alkenes}
- C08F 110/02: Ethene
- C08F 210/16: Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- 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 power cable includes a conductor surrounded by one or more layers. At least one of the layers can include a polymer composition having an electric conductivity of 0.50×10−15 S/m or less when measured according to DC conductivity method using a tape sample. The polymer composition can include a polyolefin which is obtainable by a high pressure polymerization process. This process includes: compressing one or more monomers under pressure in a compressor, in which a compressor lubricant, such as mineral oil is used for lubrication; polymerizing a monomer optionally together with one or more comonomers in a polymerization zone; and separating the obtained polyolefin from the unreacted products and recovering the separated polyolefin in a recovery zone.

## Claims

### Claim 1

A direct current (DC) power cable comprising a conductor surrounded by at least an inner semiconductive layer, an insulation layer and an outer semiconductive layer, in that order, wherein the insulation layer comprises a polymer composition having an electric conductivity of 0.50×10−15 S/m or less, when measured according to DC conductivity method using a tape sample consisting of the polymer composition as described under “Determination Methods”, the polymer composition comprising a polyolefin which is a low density polyethylene (LDPE) copolymer of ethylene with a polyunsaturated comonomer obtained by a high pressure polymerization process comprising:
(a) compressing ethylene with the polyunsaturated comonomer under pressure in a compressor, wherein a compressor lubricant is used for lubrication,
(b) polymerizing ethylene with the polyunsaturated comonomer in a polymerization zone,
(c) separating the obtained polyolefin from the unreacted products and recovering the separated polyolefin in a recovery zone,
wherein the compressor lubricant comprises a mineral oil.

### Claim 2 (depends on 1)

The direct current (DC) power cable according to claim 1, wherein the polymer composition has an electrical conductivity of 0.48×10−15 S/m or less, when measured according to DC conductivity method using a tape sample consisting of the polymer composition, as described under “Determination Methods”.

### Claim 3 (depends on 1)

The direct current (DC) power cable according to claim 1, wherein the LDPE copolymer of ethylene is unsaturated.

### Claim 4 (depends on 1)

The direct current (DC) power cable of claim 1, wherein
in step a), the compressor lubricant comprises white oil as the mineral oil and is suitable for production of polymers for food or medical industry; and wherein
the polymerization step b) is operated at a pressure up to 4000 bar, and at a temperature of up to 400° C.

### Claim 5 (depends on 1)

The direct current (DC) power cable of claim 1, wherein the mineral oil has a viscosity of at least 8.5×10-6 m2/s at 100° C.

### Claim 6 (depends on 1)

A process for producing the direct current (DC) power cable according to claim 1, comprising;
applying at least the inner semiconductive layer, the insulation layer and the outer semiconductive layer on the conductor in that order wherein the insulation layer comprises the polymer composition; and optionally crosslinking at least the obtained layer of the power cable.

### Claim 7 (depends on 1)

The direct current (DC) power cable of claim 1, wherein the mineral oil is a white mineral oil.

### Claim 8 (depends on 1)

The direct current (DC) power cable of claim 1, wherein the mineral oil comprises 5% or less by weight of a hydrocarbon having less than 25 carbon atoms.

### Claim 9 (depends on 1)

The direct current (DC) power cable of claim 1, wherein the mineral oil comprises a hydrocarbon having an average molecular weight of 480 or more.