EP0674325A2 - Composition polymère isolante électrique et fils ou câble utilisant cette composition - Google Patents

Composition polymère isolante électrique et fils ou câble utilisant cette composition Download PDF

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Publication number
EP0674325A2
EP0674325A2 EP95104416A EP95104416A EP0674325A2 EP 0674325 A2 EP0674325 A2 EP 0674325A2 EP 95104416 A EP95104416 A EP 95104416A EP 95104416 A EP95104416 A EP 95104416A EP 0674325 A2 EP0674325 A2 EP 0674325A2
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Prior art keywords
monomer
group containing
functional group
polymer
electrically insulating
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EP95104416A
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German (de)
English (en)
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EP0674325A3 (fr
EP0674325B1 (fr
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Masaaki Ikeda
Junichi Yokoyama
Yuka Umeshima
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Eneos Corp
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Nippon Petrochemicals Co Ltd
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Priority claimed from JP7638094A external-priority patent/JPH07149959A/ja
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Publication of EP0674325A2 publication Critical patent/EP0674325A2/fr
Priority to CA 2159570 priority Critical patent/CA2159570C/fr
Publication of EP0674325A3 publication Critical patent/EP0674325A3/fr
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    • 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

Definitions

  • This invention relates to an electrically insulating polymer composition and a wire or a cable using such a composition. More particularly, the present invention relates to a composition that provides an excellent electrical insulator in terms of volume resistivity, breakdown strength and other electrical properties. It also relates to a polymer composition for providing an excellent electrical insulator that does not degrade in terms of volume resistivity, breakdown strength and other electrical properties as well as to a wire, a cable or a DC power cable comprising an electrically insulating polymer composition or an insulation layer formed by such a composition or a material obtained by crosslinking such a composition
  • Insulating materials for wires or cables are, by definition, required to show a high volume resistivity, a high breakdown strength, a low dielectrical constant and a low loss tangent and typically made of polyethylene.
  • oil-fill insulators hereinafter referred to as OFs
  • the OF is accompanied by certain draw-backs including that it should be constantly supplied with oil to offset the quantity of oil that leaks out of it.
  • crosslinked olefinic polymers such as crosslinked polyethylene are getting popularity as they show an enhanced level of thermal resistance and physical strength.
  • crosslinking include electron beam induced crosslinking and chemical crosslinking using peroxides and the like, of which the former requires large equipment and hence costly. While chemical crosslinking is less costly, crosslinking agents can remain in the products and gradually reduce the volume resistivity of the products , and give rise to water trees and other problems.
  • Japanese Patent Publication No. 5-15007 proposes a method of introducing polyolefin that is modified with maleic anhydride into polyethylene for the purpose of introducing hydrophilic groups.
  • Japanese Patent Laid-open Publication No. 4-11646 discloses a method of improving the electrical insulation of an insulating material by introducing double bonds in advance into polyolefin to be crosslinked and thereby reducing the rate of the use of crosslinking agent.
  • neither of these methods do not operate satisfactorily for the improvement of volume resistivity and other aspects of electrical insulation and thermal resistance.
  • the inventors of the present invention had found sometime ago that electrically highly insulating materials can be produced by using maleic anhydride at a very limited rate. While these materials surpass normally crosslinked polyolefinic materials by far for electrical insulation, they are still not satisfactorily in terms of volume resistivity and other properties of electrical insulation.
  • any of these methods cannot satisfactorily improve an insulating material of the type under consideration in terms of both the volume resistivity and the breakdown strength. They are not satisfactory either in terms of improvement in the electrical insulation of the material after crosslinking.
  • an electrically insulating polymer composition comprising an olefinic polymer as a principal ingredient and functional group containing monomeric units of monomers D1 through D4 at a rate of 5x10 ⁇ 7 to 5x10 ⁇ 3 mols per gram of the composition, and also comprising ethylenic linkages at a rate of not smaller than 0.8 per 1,000 carbon atoms and/or aromatic ring containing monomeric units of monomer D5 at a rate of 5x10 ⁇ 7 to 5x10 ⁇ 3 mols per gram of the composition, wherein said monomers D1 through D5 have an ethylenic linkage, said monomer D1 is a carbonyl group or carbonyl group derivative containing monomer, said monomer D2 is a hydroxyl group containing monomer, said monomer D3 is a nitro group containing monomer, said monomer D4 is a nitrile group containing monomer, and said monomer D5 is an aromatic
  • a wire or a cable having an electrically insulating polymer composition as defined above or an insulating layer made of such a composition or a material obtained by crosslinking such a composition.
  • Figures 1(a) and (b) are schematic illustrations of an electrode system used for testing the volume resistivity of specimens of a composition according to the present invention, wherein Fig. 1(a) is a plan view of the electrode system and Fig. 1(b) is a sectional view thereof.
  • Figure 2 is a schematic illustration of an electrode system used for testing the breakdown strength of specimens of a composition according to the present invention.
  • Figure 3 is a schematic illustration of an water tree observing system used for testing specimens of a composition according to the present invention.
  • Figure. 4 is a graph showing the performances of Examples 1 through 6 according to the present invention and those of Comparative Examples 1, 4 and 5, expressed in terms of the relationship between the functional group concentration (horizontal axis) and the volume resistivity (vertical axis).
  • Figure 5 is a graph showing the performances of Examples 7 through 10 according to the present invention and 13 through 15 and those of Comparative Examples 1, 4, 5 and 10.
  • Figure 6 is a schematic cross sectional view of a cable according to the present invention.
  • an electrically insulating polymer composition comprising an olefinic polymer as a principal ingredient and functional group containing monomeric units of monomers D1 through D4 at a rate of 5x10 ⁇ 7 to 5x10 ⁇ 3 mols per gram of the composition, and also comprising ethylenic linkages at a rate of not smaller than 0.8 per 1,000 carbon atoms and/or aromatic ring containing monomeric units of monomer D5 at a rate of 5x10 ⁇ 7 to 5x10 ⁇ 3 mols per gram of the composition, wherein said monomers D1 through D5 have an ethylenic linkage, said monomer D1 is a carbonyl group or carbonyl group derivative containing monomer, said monomer D2 is a hydroxyl group containing monomer, said monomer D3 is a nitro group containing monomer, said monomer D4 is a nitrile group containing monomer, and said monomer D5 is an aromatic ring containing monomer.
  • said electrically insulating polymer composition preferably comprises a polymer having said functional group containing monomers D1 through D4, a polymer having monomeric units containing two or more ethylenic linkages and/or a copolymer having said aromatic ring containing monomer D5.
  • said composition may preferably comprises at least one of component (A), component (B) and component (C) as defined below;
  • said olefinic polymer of the component (A1) is a homopolymer or copolymer of hydrocarbons expressed by general formula C n H 2n which can be selected from ethylene, propylene, 1-butene, 2-butene, isobutylene, 1-pentene, 2-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, 1-hexene, 2,3-dimethyl-2-butene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene and so on.
  • C n H 2n which can be selected from ethylene, propylene, 1-butene, 2-butene, isobutylene, 1-pentene, 2-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, 1-hexene, 2,3-dimethyl-2-butene, 4-methyl-1-pentene, 1-hep
  • Examples of the olefinic polymers that can be used for the purpose of the present invention include high, medium or low density polyethylene, linear low density polyethylene, very low density polyethylene, polypropylene, polybutene, polypentene, poly-4-methyl-1-pentene, ethylene- ⁇ -olefin copolymer, ethylene-propylene copolymeric rubber (EPR), low density polyethylene obtained by a high pressure radical method and ethylene copolymer obtained by a high pressure radical method.
  • EPR ethylene-propylene copolymeric rubber
  • low density polyethylene obtained by a high pressure radical method high, medium or low density polyethylene, linear low density polyethylene and polypropylene are preferable.
  • a functional group containing monomers having an ethylenic linkage may be the monomer D1: carbonyl group or carbonyl group derivative containing monomer, the monomer D2: hydroxyl group containing monomer, the monomer D3: nitro group containing monomer, the monomer D4: nitrile group containing monomer and the monomer D5: aromatic ring containing monomer. Specific examples of such monomers will be listed below.
  • Examples of the carbonyl group or carbonyl group derivative containing monomer D1 include unsaturated carboxylic acids derived from ⁇ , ⁇ -unsaturated carboxylic acids, unsaturated carboxylates derived from ⁇ , ⁇ -unsaturated carboxylates and vinylester monomers.
  • Examples of unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid.
  • unsaturated carboxylates include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, methyl maleate, ethyl maleate, dimethyl maleate, diethyl maleate, methyl fumarate, ethyl fumarate, glycidyl acrylate and glycidyl methacrylate.
  • vinylester examples include vinyl propionate, vinyl acetate, vinyl caproate, vinyl caprylate, vinyl laurate, vinyl stearate and vinyl trifulorate, of which vinyl acetate is most preferable.
  • acid anhydrides to be used for carbonyl group derivative containing monomers for the purpose of the present invention include maleic anhydride, itaconic anhydride, methylmaleic anhydride, dimethylmaleic anhydride, phenylmaleic anhydride, diphenylmaleic anhydride, chloromaleic anhydride, dichloromaleic anhydride, fluoromaleic anhydride, difluoromaleic anhydride, bromomaleic anhydride and dibromomaleic anhydride, of which maleic anhydride is most preferable.
  • Examples of the hydroxyl group containing monomer D2 include vinylalcohol, 1-hydroxypropyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate and hydroxyethyl(meth)acrylate.
  • nitro group containing monomer D3 examples include 2,4-dinitrophenyl acrylate, 2-nitrostyrene, m-nitrostyrene, o-nitrostyrene, p-nitrostyrene, p-nitrophenyl methacrylate, m-nitrophenyl methacrylate, 2,4-di-nitrophenyl methacrylate and 2,4,6-tri-nitrophenyl methacrylate.
  • nitrile group containing monomer D4 examples include acrylonitrile, methacrylonitrile, ⁇ -methoxyacrylonitrile, vinylidenecyanide, cinnamonitrile, crotononitrile, ⁇ -phenylcrotononitrile, fumaronitrile, arylacetonitrile, 2-butenenitrile and 3-butenenitrile.
  • the aromatic ring containing monomer D5 is a compound containing a monocyclic or polycyclic aromatic ring and having ethylenic linkages.
  • aromatic ring containing monomer D5 that can be used for the purpose of the present invention are preferably aromatic compounds containing a monocyclic, dicyclic or tricyclic aromatic ring and include styrene and its derivatives, arylbenzene, arylbiphenyl, methylstyrene, aryl benzoate, vinylnaphthalene, 4-phenyl-1-butene, benzil methacrylate, 1,1-diphenylethylene, 4-phenyl-1-tolylethylene, 1-phenyl-1-styrylethane, 1-tolyl-1-styrylethane, 2,4-diphenyl-1-butene, 2,4-diphenyl-1-pentene and 2,4-diphenyl-4-methyl-1-pentene.
  • styrene is most preferably in terms of the electrical performance of the final product.
  • the concentration of the functional groups of the monomers of D1 through D4 including maleic anhydride is less than 5x10 ⁇ 7 mols per one gram of the polymer composition, the volume resistivity of the final product would not be improved. If the same is true with the functional group of the monomer of D5, the breakdown strength of the final product would not be improved either. If, on the other hand, the concentration is greater than 5x10 ⁇ 3 mols per one gram of polymer composition, the volume resistivity of the final product is degraded.
  • Copolymers that can be used for a random copolymer of olefin and at least one of said functional group containing monomers D1 through D5 or a graft copolymer obtained by modifying an olefinic polymer with at least one of said functional group containing monomers D1 through D5 as defined for the component (A2) include linear low density polyethylene modified with acrylic acid or maleic anhydride, high, medium or low density polyethylene modified with acrylic acid or maleic anhydride, copolymer of ethylene and acrylic acid or maleic anhydride, copolymer of ethylene and carbon monoxide, ethylene-methylvinylketone copolymer, ethylene-methylisopropenylketone copolymer, ethylene-hydroxyethyl(meth)acrylate copolymer, ethylene-2-nitrostyrene copolymer, ethylene-m-nitrostyrene copolymer, ethylene-p-nitrophenylmethacrylate copolymer, ethylene(
  • a homopolymer derived from a monomer containing two or more ethylenic linkages or a copolymer of said monomer and ethylene as defined for the component (B1) needs to contain double bonds to a sufficient rate after polymerization. According to the existence of the ethylenic linkages, the final product shows a satisfactory crosslinked effect.
  • a liquid oligomer or copolymer having an average molecular weight of 1,000 to 200,000 will be used.
  • a homopolymer derived from a monomer containing two or more ethylenic linkages as defined in the former half of (B1) is a diene polymer having 4 to 10 carbon atoms.
  • the diene polymer may be cyclic or straight chain so long as it has two or more double bonds.
  • butadiene oligomer or polybutadiene having an average molecular weight of 1,000 to 20,000 is most preferable because it is excellent in terms of electrical insulation and crosslinking efficiency after crosslinking.
  • Examples of such compounds include 1,3-butadiene, 1,3-pentadiene, 1,4-pentadiene, 2-methyl-1,3-butadiene, 1,3-hexadiene, 1,4-hexadiene, 1,5-hexadiene, 2,4-hexadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-heptadiene, 1,4-heptadiene, 3-(2-propenyl)-cyclopentene and 2-(cyclopentyl)-1,3-butadiene.
  • Trienes and tetraenes that can be prepared from dienes by polymerization can also be used.
  • Compounds that can be used a random copolymer of monomer containing two or more ethylenic linkages and ethylene as defined in the latter half of (B1) include ethylene-aryl(meth)acrylate copolymer and ethylene-vinyl(meth)acrylate copolymer. Alternatively, a mixture of two or more of such copolymers may be used.
  • Examples of a random copolymer of a monomer containing two or more ethylenic linkages and at least one of said functional group containing monomers D1 through D5, a random copolymer of a monomer containing two or more ethylenic linkages, ethylene and at least one of said functional group containing monomers D1 through D5 or a graft copolymer obtained by modifying a homopolymer derived from a monomer containing two or more ethylenic linkages or a copolymer of said monomer and ethylene with at least one of said functional group containing monomers D1 through D5 as defined in (B2) include polybutadiene modified with acrylic acid or maleic anhydride, maleic anhydride-butadiene copolymer, maleic acid-modified ethylene-aryl(meth)acrylate copolymer and maleic acid-modified ethylene-vinyl(meth)acrylate copolymer.
  • polybutadien modified with acrylic acid or maleic anhydride is most preferable.
  • Examples of compounds that can be used for a compound containing two or more ethylenic linkages as defined in (B3) include methacrylate monomers having a number of functional groups such as trimethylolpropane trimethacrylate, ethyleneglycol dimethacrylate and diethyleneglycol dimethacrylate; vinyl monomers having a number of functional groups such as triarylisocyanurate, diarylphthalate and vinylbutyrate; bismaleimides such as N,N'-m-phenylenebismaleimide and N,N'-ethylenbismaleimide; dioximes such as P-quinonedioxime; divinyl compounds such as divinylbenzene, 1,5-hexadiene-3-in, hexatriene, divinylether, divinylsulfone; and diaryl compounds such as arylstyrene, 2,6-diacrylphenol, diarylcarbinol.
  • methacrylate monomers having a number of functional groups such as
  • the composition contains at a rate not less than 0.8 double bonds per 1,000 carbon atoms.
  • the number of double bonds is between 0.8 and 4.0 per 1,000 carbon atoms.
  • the number of terminal vinyl group is between 0.5 and 3.0 per 1,000 carbon atoms.
  • An olefinic polymer containing at least one aromatic ring as defined in (C1) above is a copolymer of a monomer containing a monocyclic or polycyclic aromatic ring and olefin.
  • a monomer containing at least one aromatic ring is preferably an aromatic compound having a mono-, di- or tricyclic aromatic ring and selected from compounds including styrene, styrene derivatives, arylbenzene, arylbiphenyl, methylstyrene, aryl benzoate, vinylnaphthalene, 4-phenyl-1-butene, benzyl methacrylate, 1,1-diphenylethylene, 1-phenyl-tolylethylene, 1-phenyl-1-styrylethane, 2,4-diphenyl-1-butene, 2,4-diphenyl-1-pentene and 2,4-diphenyl-4-methyl-1-pentene.
  • Olefines that can be used in component (C1) for the purpose of the invention include ⁇ -olefines having 3 to 12 carbon atoms such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and 1-decene.
  • ethylene-styrene random copolymer is most preferable.
  • a random copolymer of olefin, at least one of said functional group containing monomers D1, and said aromatic ring containing monomer D5 or a graft copolymer obtained by modifying an olefinic polymer containing aromatic rings with at least one of said functional group containing monomers D1 through D4, or a graft copolymer obtained by modifying a random copolymer of olefin and at least one of said functional group containing monomers D1 through D4 with said aromatic ring containing monomer D5 as defined in component (C2) above is selected from compounds including ethylene-styrene-maleic anhydride random copolymer, maleic anhydride modified ethylene-styrene copolymer, ethylene-arylbenzen copolymer, maleic anhydride modified ethylene-benzyl methacrylate copolymer, and maleic anhydride modified ethylene-arylstyrene.
  • copolymers of at least one of monomers containing a styrene derivative and ethylene that can be used for the purpose of the present invention include ethylene/vinylacetate/styrene copolymer, ethylene/vinylacetate/ ⁇ -methylstyrene copolymer, ethylene/ethyl acrylate/styrene copolymer and ethylene/ethyl acrylate/ ⁇ -methylstyrene copolymer.
  • the concentration of said aromatic containing monomer in the composition is between 5x10 ⁇ 7 and 5x10 ⁇ 3 mols, preferably between 1x10 ⁇ 6 and 1x10 ⁇ 4 mols and most preferably between 1x10 ⁇ 6 and 5x10 ⁇ 5 mols per 1 gram of the polymer composition.
  • composition according to the present invention may well be used by itself as an electrically insulating material, it is preferable to crosslink it in order to improve the volume resistivity and the breakdown strength. While any appropriate crosslinking techniques including the use of a radical generating agent such as an organic peroxide, electron beam induced crosslinking and silane crosslinking may be used, the use of a radical generating agent is preferable in view of cost effectiveness.
  • a radical generating agent such as an organic peroxide, electron beam induced crosslinking and silane crosslinking
  • radical generating agents examples include peroxides such as benzoylperoxide, laurylperoxide, dicumylperoxide, t-butylhydroperoxide, ⁇ , ⁇ -bis(t-butylperoxideisopropyl)benzene, di-t-butylperoxide, 2,5-di(t-butylperoxy)hexane, 2,5-di(t-butylperoxy)hexene; azobisisobutylonitrile, 2,3-dimethyl-2,3-diphenylbutane, 2,3-diethyl-2,3-diphenylbutane, 2,3-diethyl-2,3-di(p-methylphenyl)butane and 2,3-diethyl-2,3-di(bromophenyl)butane.
  • peroxides such as benzoylperoxide, laurylperoxide, dicumylperoxide, t-buty
  • the volume resistivity and other electrical properties of the composition can be improved by crosslinking the composition after preparing a given amount of component (B).
  • the radical generating agents for modifying component (B) with an functional group containing monomer as described above may mostly used as crosslinking agents for the purpose of the present invention.
  • crosslinking agents listed above, dicumylperoxide, 2,5-di-(t-butylperoxy)hexane and 2,5-di-(t-butylperoxy)hexene are recommendable.
  • the crosslinking agent is used by an amount between 0.01 to 5 parts by weight, preferably between 0.1 and 3 parts by weight, for a total of 100 parts by weight of the composition.
  • composition according to the present invention may include one or more chemicals selected from inorganic fillers, organic fillers, antioxidants, lubricants, organic or inorganic pigments, ultraviolet preventing agents, photostabilizers, dispersing agents, anti-copper-corrosion agents, neutralizing agents, plasticizers, and nucleating agents.
  • An insulating polymer composition according to the present invention can be used for insulating materials for wires, cables and capacitors, for the insulation of high voltages areas of X-ray generators and cables and other applications.
  • a wire or a cable according to the present invention is one comprising an insulation layer made of a polymer composition according to the present invention or a composition obtained by crosslinking said composition.
  • a wire or a cable according to the present invention is one comprising an insulation layer covering its conductor. If necessary, a bundle of wires may be used for the conductor and a semiconducting layer may be arranged between the conductor and the insulation layer. A flame retarding polymer layer may be formed outside the insulation layer.
  • a wire or a cable may be prepared by coating a bundle of copper wires with a polymer composition containing carbon powder or metal powder to form semiconducting layer, forming thereon an insulation layer of a polymer composition according to the present invention, arranging thereon a coat of metal sheet or still another semiconducting layer and then forming an outermost coat of a flame retarding or rat repellent polymer layer.
  • a wire or a cable may be prepared by combining several to tens of several covered copper wires, each comprising a single copper wire coated with a semiconducting layer of a polymer composition containing carbon or metal powder and an insulation layer of a polymer composition according to the present invention, and forming an outermost coat of a flame retarding or rat repellent polymer layer.
  • a polymer composition according to the present invention is particularly effective for high voltage and can be suitably used for DC power cables.
  • the present invention provides an electrically insulating polymer composition
  • an electrically insulating polymer composition comprising an olefinic polymer as a principal ingredient and a functional group containing monomer, and also comprising ethylenic linkage and/or an aromatic ring containing monomer.
  • the functional group operates as a trap site that blocks the movement of electrical charges and consequently improve the volume resistivity of the composition.
  • the aromatic ring has an effect of taking up highly energized electrons, causing them to emit their energy in the form of heat and releasing them with a low energy level (electron energy absorption effect).
  • the energy level of highly energized electrons that can trigger electrical breakdown can be significantly reduced to enhance the breakdown strength of the composition.
  • the electrical properties of an insulating material prepared from a polymer composition according to the present invention can be improved by crosslinking particularly in terms of volume resistivity, the phenomenon of water tree and breakdown strength.
  • the double bonds in a diene polymer improves the efficiency of crosslinking since they operates as crosslinking sites.
  • the decomposition residues of the crosslinking agent are taken up in the main chain of the polymer.
  • the decomposition residues floating in the bulk can reduce the volume resistivity as they are subjected to ionic decomposition to produce electrical charges by heat and the electrical field. Such a detrimental effect of decomposition residues can be prevented by taking them up into the main chain of the polymer and consequently the volume resistivity of the composition is improved.
  • the degradation in the electrical properties of an insulating material can be effectively avoided by the above three effects of the present invention. Additionally, the volume resistivity and the breakdown strength of the composition are remarkably improved after crosslinking.
  • FIG. 1(a) and 1(b) An electrode system as shown in Figs. 1(a) and 1(b) was used.
  • the specimens were tested by applying a DC voltage of 3,300 V at room temperature and at 90°C in a nitrogen atmosphere.
  • a vibrating reed type ampere meter (TR8411 available from Advantest, Co.,Ltd.) was used for gauging the volume resistivity.
  • Each specimen had a thickness of 0.3 mm and an effective electrode surface area of 19.6 cm2.
  • the volume resistivity was determined by the electrical current observed 10 minutes after the start of applying the voltage.
  • Each specimen was tested four times and the average of the readings was used.
  • Figs. 1(a) and 1(b) illustrating the electrode system 11 denotes a main electrode (50 ⁇ ), 12 denotes a guard electrode (inner diameter 75 ⁇ , outer diameter 80 ⁇ ), 13 denotes a specimen and 14 denotes a high voltage electrode (80 ⁇ ).
  • the electrode system comprises a substrate 24 made of polymethylmethacrylate and bored at the center to a diameter of 1/2 inch and electrodes 21 of stainless steel balls with a diameter of 1/2 inch.
  • Each specimen 22 was cut to a dice of 8 to 10 mm and arranged between the electrodes. The gap between the specimen and the electrodes was filled with deaerated epoxy resin, which was then hardened.
  • the McKewon electrodes were dipped into silicon oil contained in a vessel, which was then put into a thermostat for observation.
  • the voltage used for this breakdown test had an impulse waveform of 1.2/50 ⁇ S and negative polarity. The waveform was observed by means of an oscilloscope and the reading of the wave crest where breakdown occurred was recorded for each test. The average of more than twenty readings was used.
  • Fig. 2 illustrating the gauging system for the breakdown strength test, 21 denotes a pair of stainless steel balls, 22 denotes a specimen, 23 denotes epoxy resin and 24 denotes a substrate made of polymethylmethacrylate.
  • a water tree observing system having a configuration as described in Fig. 3 was used. A voltage of 10 kV and 10 kHz was applied to each specimen at room temperature.
  • Fig. 3 illustrating the water tree observing system
  • 31 denotes specimens being observed water trees
  • 32 denotes a conducting plate
  • 33 denotes water
  • 34 denotes a grounding electrode
  • 35 denotes vessels
  • 36 denotes a voltage applying electrode.
  • a set of chemicals selected from components (A), (B) and (C) were used to a ratio as indicated in one of Table 1-1 through 1-3.
  • 2 parts by weight of dicumylperoxide was used as a crosslinking agent in each examples and each comparative examples except for examples 31-43.
  • the ingredients were molten and mixed in a biaxial extruder. Liquid and modified specimens were introduced through a bent inlet. Subsequently, the polymer was pressed into a sheet and tested for volume resistivity, breakdown strength and water tree.
  • Fig. 4 is a graph showing the performances of Examples 1 through 6 and those of Comparative Examples 1, 4 and 5, expressed in terms of the relationship between the functional group concentration (horizontal axis) and the volume resistivity (vertical axis).
  • the marks ⁇ and ⁇ are the results of the examples according to the present invention, and the other marks ⁇ and ⁇ are the results of the comparative ones. Further, the marks ⁇ and ⁇ are the results at room temperature and the other marks ⁇ and ⁇ are the results at 90°C.
  • Fig. 5 is a graph showing the performances (marks ⁇ , ⁇ , ⁇ and ⁇ ) of Examples 7 through 10 and 13 through 15 and those (the other marks ⁇ and ⁇ ) of Comparative Examples 1, 4, 5 and 10. Note that the volume resistivity was improved by using A1-1 and A2-1 for (A) and also by adding B2-1 to C1-1.
  • Sample cables having a configuration as shown in Fig. 6 were prepared by using the composition of Example 3. When tested, they performed remarkably well.
  • Fig. 6 illustrating a sample cable 41 denotes a conducting member which is a bundle of conducting metal wires, 42 denotes an internal semiconducting layer, 43 denotes an insulating polymer composition layer, 44 denotes an external semiconducting layer, 45 denotes an aluminum foil and 46 denotes a protective member (made of polyolefin containing an inorganic flame retarding agent).
  • the present invention provides an electrically insulating polymer composition
  • an electrically insulating polymer composition comprising an olefinic polymer as a principal ingredient and also comprising specific functional group containing monomeric units and/or aromatic ring containing monomeric units.
  • Such a polymer composition is excellent in the volume resistivity, the breakdown strength and other electrically insulating properties. It is also sensitive to crosslinking and, if crosslinked, it does not lose its remarkable volume resistivity, the breakdown strength and other electrically insulating properties.
  • a polymer composition according to the present invention and a crosslinked material obtained from such a composition can be used to form an insulating layer for wires or cables in general and DC power cables in particular.
  • a polymer composition according to the present invention finds a wide variety of applications including insulating materials for wires or cables in general and DC power cables in particular to be used for electrical appliances, transportation equipment, plants and factories.

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  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Organic Insulating Materials (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Graft Or Block Polymers (AREA)
EP19950104416 1994-03-24 1995-03-24 Composition polymère isolante électrique et fils ou câble utilisant cette composition Expired - Lifetime EP0674325B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA 2159570 CA2159570C (fr) 1995-03-24 1995-09-29 Composition polymerique isolante; fil et cable utilisant cette composition

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP7638094A JPH07149959A (ja) 1993-10-07 1994-03-24 電気絶縁用樹脂組成物
JP7638094 1994-03-24
JP76380/94 1994-03-24
JP167443/94 1994-06-27
JP16744394 1994-06-27
JP16744394 1994-06-27

Publications (3)

Publication Number Publication Date
EP0674325A2 true EP0674325A2 (fr) 1995-09-27
EP0674325A3 EP0674325A3 (fr) 1995-12-20
EP0674325B1 EP0674325B1 (fr) 2003-11-05

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WO1999044206A1 (fr) * 1998-02-25 1999-09-02 Abb Ab Cable electrique isole
WO2001092357A1 (fr) * 2000-05-26 2001-12-06 Dow Global Technologies Inc. Interpolymere sensiblement aleatoire greffe a un ou a plusieurs monomeres organiques alceniques
US7098525B2 (en) 2003-05-08 2006-08-29 3M Innovative Properties Company Organic polymers, electronic devices, and methods
US7279777B2 (en) 2003-05-08 2007-10-09 3M Innovative Properties Company Organic polymers, laminates, and capacitors
WO2008006531A1 (fr) * 2006-07-10 2008-01-17 Borealis Technology Oy Couche de câble à base de polypropylène avec haute résistance au claquage électrique
US7799841B2 (en) 2006-08-25 2010-09-21 Borealis Technology Oy Polypropylene foam
US7914899B2 (en) 2006-07-10 2011-03-29 Borealis Technology Oy Electrical insulation film
US7915367B2 (en) 2006-12-28 2011-03-29 Borealis Technology Oy Process for the manufacture of branched polypropylene
US8142902B2 (en) 2006-08-25 2012-03-27 Borealis Technology Oy Extrusion coated substrate
US8247052B2 (en) 2006-09-25 2012-08-21 Borealis Technology Oy Coaxial cable
CN102782031A (zh) * 2010-03-08 2012-11-14 北欧化工股份公司 包含苯偶酰型电压稳定剂的用于中/高/超高压电缆的聚烯烃组合物
US8378047B2 (en) 2006-07-10 2013-02-19 Borealis Technology Oy Biaxially oriented polypropylene film

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EP1847555A1 (fr) 2006-04-18 2007-10-24 Borealis Technology Oy Polypropylène à ramifications multiples

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EP0463402A2 (fr) * 1990-06-04 1992-01-02 Nippon Petrochemicals Company, Limited Polymères d'éthylène présentant des propriétés d'isolation améliorées, compositions et câbles d'énergie fabriqués avec ces polymères
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JPH04118808A (ja) * 1990-09-07 1992-04-20 Nippon Petrochem Co Ltd 耐水トリー性に優れるエチレン系重合体または該エチレン系重合体組成物及びこれを用いた電力ケーブル
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JPH05298926A (ja) * 1992-04-20 1993-11-12 Nippon Petrochem Co Ltd エチレン系共重合体またはその組成物からなる高絶縁体およびこれを用いた電力ケーブル
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Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999044206A1 (fr) * 1998-02-25 1999-09-02 Abb Ab Cable electrique isole
WO2001092357A1 (fr) * 2000-05-26 2001-12-06 Dow Global Technologies Inc. Interpolymere sensiblement aleatoire greffe a un ou a plusieurs monomeres organiques alceniques
US7098525B2 (en) 2003-05-08 2006-08-29 3M Innovative Properties Company Organic polymers, electronic devices, and methods
US7279777B2 (en) 2003-05-08 2007-10-09 3M Innovative Properties Company Organic polymers, laminates, and capacitors
US7473652B2 (en) 2003-05-08 2009-01-06 3M Innovative Properties Company Organic polymers, electronic devices, and methods
CN101479811B (zh) * 2006-07-10 2012-12-26 博里利斯技术有限公司 基于聚丙烯的具有高电击穿强度的电缆层
WO2008006531A1 (fr) * 2006-07-10 2008-01-17 Borealis Technology Oy Couche de câble à base de polypropylène avec haute résistance au claquage électrique
EP1881508A1 (fr) * 2006-07-10 2008-01-23 Borealis Technology Oy Cables en nappé a base de polypropylene presentant une meilleure résistance au claquage diélectrique
EP1881507A1 (fr) * 2006-07-10 2008-01-23 Borealis Technology Oy Cables en nappé a base de polypropylene presentant une meilleure résistance au claquage diélectrique
US7914899B2 (en) 2006-07-10 2011-03-29 Borealis Technology Oy Electrical insulation film
EA019563B1 (ru) * 2006-07-10 2014-04-30 Бореалис Текнолоджи Ой Слой кабеля, содержащий гомополимер пропилена, применение слоя кабеля в качестве изолирующего или полупроводящего слоя и кабель, содержащий такой слой
US8378047B2 (en) 2006-07-10 2013-02-19 Borealis Technology Oy Biaxially oriented polypropylene film
US7799841B2 (en) 2006-08-25 2010-09-21 Borealis Technology Oy Polypropylene foam
US8142902B2 (en) 2006-08-25 2012-03-27 Borealis Technology Oy Extrusion coated substrate
US8247052B2 (en) 2006-09-25 2012-08-21 Borealis Technology Oy Coaxial cable
US7915367B2 (en) 2006-12-28 2011-03-29 Borealis Technology Oy Process for the manufacture of branched polypropylene
CN102782031A (zh) * 2010-03-08 2012-11-14 北欧化工股份公司 包含苯偶酰型电压稳定剂的用于中/高/超高压电缆的聚烯烃组合物
CN102782031B (zh) * 2010-03-08 2014-11-12 北欧化工股份公司 包含苯偶酰型电压稳定剂的用于中/高/超高压电缆的聚烯烃组合物

Also Published As

Publication number Publication date
NO951116D0 (no) 1995-03-23
NO951116L (no) 1995-09-25
NO314475B1 (no) 2003-03-24
EP0674325A3 (fr) 1995-12-20
EP0674325B1 (fr) 2003-11-05

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