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WO2000024008A1 - Composition pour cable electrique - Google Patents

Composition pour cable electrique Download PDF

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Publication number
WO2000024008A1
WO2000024008A1 PCT/SE1999/001887 SE9901887W WO0024008A1 WO 2000024008 A1 WO2000024008 A1 WO 2000024008A1 SE 9901887 W SE9901887 W SE 9901887W WO 0024008 A1 WO0024008 A1 WO 0024008A1
Authority
WO
WIPO (PCT)
Prior art keywords
composition
formula
compound
ethylene
molecular weight
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/SE1999/001887
Other languages
English (en)
Inventor
Hans Eklind
Bill Gustafsson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Borealis AS
Borealis Technology Oy
Original Assignee
Borealis AS
Borealis Technology Oy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Borealis AS, Borealis Technology Oy filed Critical Borealis AS
Priority to AU14282/00A priority Critical patent/AU1428200A/en
Publication of WO2000024008A1 publication Critical patent/WO2000024008A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
    • H01B3/30—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes
    • H01B3/44—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes vinyl resins; acrylic resins
    • H01B3/441—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes vinyl resins; acrylic resins from alkenes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L71/00—Compositions of polyethers obtained by reactions forming an ether link in the main chain; Compositions of derivatives of such polymers
    • C08L71/02—Polyalkylene oxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
    • H01B7/28—Protection against damage caused by moisture, corrosion, chemical attack or weather
    • H01B7/2813—Protection against damage caused by electrical, chemical or water tree deterioration

Definitions

  • the present invention relates to a composition for electric cables. More particularly, the present invention relates to a composition for insulating and semiconduct- ing layers of an electric power cable having improved water treeing properties and a low dissipation factor.
  • Electric cables and particularly electric power cables for medium and high voltages may be composed of a plurality of polymer layers extruded around the electric conductor.
  • the electric conductor is usually coated first with an inner semiconductor layer followed by an insulating layer, then an outer semiconductor layer followed by water barrier l,ayers, if any, and on the outside a sheath layer.
  • the layers of the cable are based on different types of ethylene plastics, which usually are crosslinked.
  • ethylene plastic is meant, generally and in connection with the present invention, a plastic based on ethylene homo- and/or copolymers of ethylene, wherein the ethylene monomer constitutes the major part of the mass.
  • polyethylene plastics may be composed of homopolymers or copolymers of ethylene, wherein the copolymers may be graft copolymers or copolymers of ethylene and one or more monomers which are co- polymerisable with ethylene.
  • the inner semiconducting layer normally comprises an ethylene copoly er, such as an ethylene-vinyl acetate copolymer (EVA) , an ethylene-ethyl acrylate copolymer (EEA) , or an ethylene-butyl acrylate copolymer (EBA) together with a sufficient amount of carbon black to make the composition semiconducting.
  • EVA ethylene-vinyl acetate copolymer
  • ESA ethylene-ethyl acrylate copolymer
  • EBA ethylene-butyl acrylate copolymer
  • the composition of the outer semiconducting layer differs depending on whether it has to be strippable or not.
  • a strippable semiconducting layer comprises an ethylene copolymer, such as an ethylene-vinyl acetate copolymer (EVA) , optionally together with an acrylonitrile-butadiene rubber (NBR) , and sufficient carbon black to make the composition semiconducting.
  • EVA ethylene-vinyl acetate copolymer
  • NBR acrylonitrile-butadiene rubber
  • a non-strippable (bonded), outer semiconducting layer may comprise EVA, EEA or EBA together with an amount of carbon black sufficient to make the composition semiconducting.
  • a limitation of ethylene plastic is its tendency to be exposed, in the presence of water and under the action of strong electric fields, to the formation of dendri- tically branched defects, so-called water trees, which can lead to breakdown and possible electric failure. This tendency is strongly affected by the presence of inhomo- geneities, microcavities and impurities in the material.
  • Water treeing has been studied carefully, especially since the 1970 's, when polymer materials and, in particular, cross-linked polyethylene became the predominant insulating material for electric cables for medium and high voltages. In the past years, these studies have entailed improvements in the construction of the cables, the manufacturing procedure and the quality and cleanliness of the used materials. These improvements have resulted in an increased service life of the manufactured cables.
  • US Patent Specification US-A-4 , 812 , 505 discloses a composition, which is usable as insulating layer in electric cables and which is resistant to water treeing.
  • the composition comprises a copolymer of ethylene and at least one alpha-olefin having 4-8 carbon atoms, such as 1-butene, 1-hexane or 1-octene, and besides comprises a polyethylene glycol having a molecular weight in the range of about 1 000-20 000 in an amount of 0.1-20% by weight .
  • the present invention thus provides a composition for an electric cable, characterised in that it comprises an ethylene plastic and an aromatic ether compound of the general formula (I)
  • the compound according to the invention is the reaction product of diglycidyl Bisphenol A and a glycol, i.e. a Bisphenol A diglycidyl ether of a glycol.
  • This compound is an aromatic ether compound and if two or more Bisphenol A diglycidyl ether units are included the compound is a polyaromatic ether.
  • the glycol unit of the aromatic ether compound of formula I is derived from polyethylene glycols, polypropylene glycols or poly-1 , 4-butylene glycols, preferably polyethylene glycols.
  • the number of ethylene, pro- pylene or 1, 4-butylene glycol units in the glycol moieties may vary within wide limits.
  • the number of glycol units are selected so that the molecular weight of each glycol moiety lies in the range 1 opo-10 000, preferably 2 000-10 000, and more preferably 4 000-8 000.
  • the molecular weight of the glycol units should also be selected within these ranges so that the molecular weight of the aromatic ether compound of formula I is 4 000-50 000, preferably 10 000-35 000.
  • the reason for this is that when the aromatic ether compound of formula I has a molecular weight below 4 000 its compatibility with the ethylene plastic of the composition is poor and problems with exudation of the aromatic ether compound may occur.
  • the molecular weight of the aromatic ether compound of formula I is more than 35 000 no further advantages are achieved and the compound is more difficult and expensive to prepare.
  • an upper limit of 50 000 has been set for the molecular weight of the aromatic ether compound of formula I.
  • the molecular weight of the aromatic ether compound of formula I lies in the range 15 000-35 000.
  • the number of Bisphenol A units in the compound may vary.
  • the compound of formula (I) is incorporated in the composition of the invention in an amount effective for inhibiting the generation of water trees. Generally, this means that the compound of formula (I) is incorporated in an amount of about 0.05-2% by weight, preferably 0.1-1% by weight of the composition.
  • the composition of the present invention may include conventional additives, such as antioxidants to counteract decomposition due to oxidation, radiation, etc.; lubricating additives, such as stearic acid; crosslinking additives, such as peroxides which decompose upon heating and initiate crosslinking; and other water tree retarding additives besides the compound of formula (I) according to the present invention.
  • the overall amount of additives, including the compound of formula (I) in the com- position of the present invention should not exceed about 10% by weight of the composition.
  • composition of the invention predominantly comprises an ethylene plastic as indicated earlier.
  • a composition for an insulating layer of an electric cable may for example comprise about 0.05% to about 10% by weight of the compound of formula (I) together with other conventional and optional additives; 0 to about 4% by weight of a peroxide crosslinking agent; the remainder of the composition substantially consisting of an ethylene plastic.
  • ethylene plastic preferably is an LDPE, i.e. an ethylene homopolymer or an LLDPE, i.e. a copolymer of ethylene and one or more alpha-olefins with 3-8 carbon atoms, such as 1-butene, 4 -methyl-1-pentene, 1-hexene, and 1-octene.
  • the amount of alpha-olefin co- monomer (s) may be in the range from about 1% to about 40% by weight of the ethylene plastic.
  • the composition may comprise one or more polar ethylene copoly- mer(s), e.g. EMA, EMMA, EEA or EBA.
  • compositions for insulating layers of electric cables are compared with regard to their water tree resisting (WTR) characteristics, i.e electrical breakdown strength and the dissipation factor.
  • Composition A was a standard composition without any WTR additive;
  • Composition B was a prior art composition in- eluding polyethylene glycol as WTR additive;
  • Composition C was a comparative composition including a WTR additive similar to that of the present invention, but outside the definition of formula I; and
  • Composition D was a composition according to the present invention including a compound of formula I as a WTR additive.
  • the Compositions A-D contained 0.6% by weight and 1.9% by weight of stabilising and crosslinking agents, respectively.
  • the polyethylene glycol of Composition B was a homopolymer of ethylene glycol with a molecular weight of 20 000.
  • the WTR additive of Composition C is referred to as PAE-1 below.
  • the WTR additive of Composition D is referred to as PAE-2 below.
  • compositions of the insulating compositions A-D are shown in Table 1.
  • the WTR additive of the present invention affords very much improved dielectric strength and dissipation factor to the insulating composition.
  • the inventive Composition D thus has dielectric strength and dissipation factor very much improved compared to both Composition A (without WTR additive) and Compositions B and C.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Organic Insulating Materials (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Abstract

Composition destinée à un câble électrique. La composition se caractérise en ce qu'elle contient un plastique éthylénique et un composé d'éther aromatique de la formule (I): HO((RO)n-CH2CH(OH)CH2O-Ph-C(CH3)2-Ph-OCH2CHOHCH2O)m-(RO)nH dans laquelle Ph représente du 1,4-phénylène; n est compris entre 20 et 250; m est compris entre 2 et 10 et R représente -CH2CH2-, formule (II), -CH2CH2CH2- ou -CH2CH2CH2CH2-. Le poids moléculaire du composé de formule (I) se situe entre 4 000 et 50 000. De préférence R représente -CH2CH2-, n est compris entre 45 et 180 et m entre 2 et 6.
PCT/SE1999/001887 1998-10-22 1999-10-20 Composition pour cable electrique Ceased WO2000024008A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU14282/00A AU1428200A (en) 1998-10-22 1999-10-20 A composition for an electric cable

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9803608A SE9803608D0 (sv) 1998-10-22 1998-10-22 A composition for an electric cable
SE9803608-0 1998-10-22

Publications (1)

Publication Number Publication Date
WO2000024008A1 true WO2000024008A1 (fr) 2000-04-27

Family

ID=20413039

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1999/001887 Ceased WO2000024008A1 (fr) 1998-10-22 1999-10-20 Composition pour cable electrique

Country Status (3)

Country Link
AU (1) AU1428200A (fr)
SE (1) SE9803608D0 (fr)
WO (1) WO2000024008A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7790235B2 (en) * 2002-09-17 2010-09-07 Mitsubishi Rayon Company, Ltd. Composite pressure container or tubular body and composite intermediate

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4897312A (en) * 1987-01-26 1990-01-30 Licentia Patent-Verwaltungs-Gmbh Polymer-based electrical insulation and electrical conductor insulated therewith
EP0750319A1 (fr) * 1995-06-21 1996-12-27 PIRELLI CAVI S.p.A. Composition polymère pour le revêtement de câbles électriques ayant une résistance élevée à la formation d'arborescences et câble électrique comportant cette composition

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4897312A (en) * 1987-01-26 1990-01-30 Licentia Patent-Verwaltungs-Gmbh Polymer-based electrical insulation and electrical conductor insulated therewith
EP0750319A1 (fr) * 1995-06-21 1996-12-27 PIRELLI CAVI S.p.A. Composition polymère pour le revêtement de câbles électriques ayant une résistance élevée à la formation d'arborescences et câble électrique comportant cette composition

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7790235B2 (en) * 2002-09-17 2010-09-07 Mitsubishi Rayon Company, Ltd. Composite pressure container or tubular body and composite intermediate

Also Published As

Publication number Publication date
AU1428200A (en) 2000-05-08
SE9803608D0 (sv) 1998-10-22

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