EP0606319A1 - Cable electrique - Google Patents

Cable electrique

Info

Publication number
EP0606319A1
EP0606319A1 EP92920527A EP92920527A EP0606319A1 EP 0606319 A1 EP0606319 A1 EP 0606319A1 EP 92920527 A EP92920527 A EP 92920527A EP 92920527 A EP92920527 A EP 92920527A EP 0606319 A1 EP0606319 A1 EP 0606319A1
Authority
EP
European Patent Office
Prior art keywords
wire
top layer
insulation
tracking
layer
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.)
Withdrawn
Application number
EP92920527A
Other languages
German (de)
English (en)
Inventor
David John 5 Gainsborough Way Durston
John Campbell 89 York Road Bovaird
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.)
Raychem Ltd
Original Assignee
Raychem Ltd
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
Priority claimed from GB929206164A external-priority patent/GB9206164D0/en
Application filed by Raychem Ltd filed Critical Raychem Ltd
Publication of EP0606319A1 publication Critical patent/EP0606319A1/fr
Withdrawn legal-status Critical Current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
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/02—Disposition of insulation
    • H01B7/0275—Disposition of insulation comprising one or more extruded layers of insulation
    • 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
    • H01B3/443—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 vinylhalogenides or other halogenoethylenic compounds
    • H01B3/445—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 vinylhalogenides or other halogenoethylenic compounds from vinylfluorides or other fluoroethylenic compounds
    • 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
    • H01B7/02—Disposition of insulation
    • H01B7/0291—Disposition of insulation comprising two or more layers of insulation having different electrical properties
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
    • H01B13/34—Apparatus or processes specially adapted for manufacturing conductors or cables for marking conductors or cables
    • H01B13/348—Apparatus or processes specially adapted for manufacturing conductors or cables for marking conductors or cables using radiant energy, e.g. a laser beam

Definitions

  • This invention relates to electrical wire and cable, and especially to electrical wire that is intended to be used in aircraft applications, or so-called airframe wire.
  • the wire should be resistant to arcing and tracking. Tracking is a phenomenon associated with the formation of permanent and progressive conducting paths on the surface of the material by the combined effects of an electrical field and external surface pollution. Once commenced, the carbonaceous conducting deposits often extend quickly in dendritic fashion to give a characteristic "tree" pattern until failure occurs across the surface. Electrical tracking can occur when a damaged energised bundle of wires become wet, eg. from electrolytes or condensation. This tracking may lead to flashover and arcing that causes additional wires in the bundle to become damaged.
  • a catastrophic cascade failure can result from a fault to a single wire if adjacent wires that are at a different electrical potential are also susceptible to tracking or if the bundle is in contact with a grounded structure. Tracking can occur at low voltages eg. 100V ac or less but becomes less likely as the voltage is reduced.
  • a related phenomenon is that of breakdown due to arcing. In this case a potential difference between two conductors, or between a conductor in which the insulation has been mechanically damaged, and ground, can result in the formation of an arc between the conductors or between the conductor and ground.
  • the high temperature of the arc causes the polymer to degrade extremely rapidly and form an electrically conductive carbonaceous deposit which can extend rapidly, as with wet tracking, and lead to catastrophic failure in which many or all of the wires in a bundle are destroyed.
  • Arcing can occur at very low voltages, for example 24V dc or lower, and since, unlike tracking, no electrolyte or moisture is involved, it is a particularly hazardous phenomenon. Arcs may also be struck by drawing apart two conductors between which a current is passing as described for example by J M Somerville "The Electric Arc", Methuen 1959.
  • wires that employ fluoropolymers without any aromatic polymers have also been used as airframe wires. While such wires exhibit better arcing and tracking resistance than wires that include aromatic polymers, there is still room for improvement. In particular such wires can exhibit increased tracking after heat aging. Although it is possible to incorporate anti-tracking materials into the polymer in order to reduce the tendency of the insulation to track, we have found that this has the disadvantage that the wires' scrape abrasion resistance can be unacceptably reduced by such means. The reason for this appears to be that the filler acts as an abrasive in the insulation and so wears down the insulation rapidly when the wire is tested.
  • an electrical wire which comprises an electrical conductor and electrical insulation which is based substantially solely on one or more extruded fiuoropolymer layers, the wire including a top layer that has a thickness of not more than 50 ⁇ m and which contains a quantity of an additive that suppresses arc tracking.
  • the wire according to the invention has the advantage that it exhibits a very high arc tracking resistance without the resulting reduction in abrasion resistance due to the presence of the tracking suppressing filler. This appears to be due to the fact that, when the wire is subjected to scraping, the part of the top layer that is abraded soon rubs away exposing the underlying primary jacket.
  • the underlying jacket which is substantially free of the tracking suppressing filler, does not suffer from a reduction in scrape abrasion resistance, so that the wire as a whole can have an abrasion resistance that is not significantly reduced from that of the wire before the tracking suppressing additive was incorporated.
  • the top layer is relatively thin and preferably has a thickness of not more than 40 and especially not more than 30 ⁇ m, although it will normally have a thickness of at least 20 ⁇ m.
  • the top layer may be applied in a number of ways, for example by painting or by dip-coating, but preferably it is applied by extrusion, and most preferably by coextrusion with the other layers. Extruded top layers tend to have a better adhesion to the underlying layers than those applied by other means since the polymer of the top layer is intimitely bonded to that of the underlying layer.
  • the electrical insulation may comprise a single layer only, but it is more usual for it to comprise more than one layer, usually two layers called the primary insulation and the primary jacket.
  • Fluoropolymers that may be employed in the insulation are preferably thermoplastic, and more preferably those that include hydrogen, for example tetrafluoroethylene copolymers such as ethylene-tetrafluoroethylene copolymer (ETFE) and tetrafluoroethylene-propylene copolymer; vinylidine fluoride homo- and copolymers such as polyvinylidine fluoride and vinylidine fluoride hexafluoropropylene copolymer and the like.
  • Preferred polymers are ethylene-tetrafluoroethylene copolymers in view of their balance of physical properties.
  • the polymer forming the top layer may be chosen from the same polymers as those from which the insulation is formed and is preferably the same polymer as is used for the insulation, or at least for the primary jacket, in order to improve the adhesion between them.
  • the fiuoropolymer forming the insulation will normally be crosslinked. They may be crosslinked by any convenient method, for example by irradiation or, by chemical crosslinking using, for example, a peroxide.
  • the peroxide may be absorbed on an inert carrier such as a calciu carbonate, carbon black, or kiesleguhr.
  • the wires of the present invention are crosslinked using high energy radiation.
  • Radiation dose levels to achieve crosslinking according to the present invention may range from about 20 to 800 kGy or more, but a dose of about 50 to 500 kGy is preferred. For most purposes a dose of about 80 to 200 kGy will be effective.
  • co-agents usually contain multiple unsaturated groups such as alkyl or acrylic esters. While their mode of action is not known with certainty, it is believed that they react with the initial radical formed on the polymer backbone to form a more stable radical, which undergoes a coupling reactions to form crosslinks more readily than chain scission reactions.
  • the co-agent can be for example, N,N'-m(phenylene)-dimaleimide, trimethylolpropane trimethylacrylate, tetraallyloxyethane, triallyl cyanurate, triallyl isocyanurate, tetramethylene acrylate, or polyethylene oxide glycol dimethacrylate.
  • the amount of the co-agent is preferably up to about 5 parts by weight per 100 parts of the polymer composition and preferably from 1 to 3 parts by weight per 100 parts of the polymer composition.
  • the polymer forming the top layer is preferably uncrosslinked, especially if it is a fiuoropolymer, eg. ethylene/tetrafluoroethylene copolymer, since crosslinked polymers often exhibit a greater tendency to track than the uncrosslinked polymer.
  • the wire can enjoy relatively good mechanical properties due to the fact that the bulk of the insulation is crosslinked, while the absence of crosslinking in the external surface will improve the arc tracking properties.
  • the tracking suppressing additives are an oxide of a metal or metalloid having an atomic weight of not more than 180 and belongs to groups IIA, III A, IVA, IV B or VIB of the periodic table. Examples of such materials include silica, alumina, chromium oxide, calcium oxide, tin oxide, titanium dioxide, beryllium oxide, magnesium oxide and nickel oxide.
  • the additive is preferably present in the top layer in a concentration of at least 5% and especially at least 10% by weight but preferably not more than 30% and especially not more than 20% by weight, based on the total weight of the top layer material. As indicated above, the tracking suppressing additive is preferably absent from the underlying layers.
  • the underlying layers may be entirely free of the additives or small quantities of them may be present, especially when they have another use. Normally the underlying layers will contain not more than 5% and especially not more than 2% by weight of the additive based on the total weight of the layer material.
  • the composition may contain one or more additional materials, for example fillers, flame retardants, anti-oxidants, ultraviolet stabilizers, processing aids, pigments, fungicides or the like.
  • additional materials for example fillers, flame retardants, anti-oxidants, ultraviolet stabilizers, processing aids, pigments, fungicides or the like.
  • the insulation (including the top layer) preferably has an overall thickness of not more than 40 ⁇ m and more preferably not more than 300 ⁇ m in order to reduce the size and weight of the wire.
  • the wire will have a total insulation thickness (including the top layer) in the range of from 200 to 280 ⁇ m.
  • the top layer may enable the wire to be markable by means of an infrared laser, eg. a CO 2 laser, if the top layer has a colour that contrasts with that of the underlying insulation.
  • an infrared laser eg. a CO 2 laser
  • part of the top layer is removed by the laser to expose the underlying, colour-contrasting layer.
  • a wire 1 comprises a conductor 2 for example a conventional nickel plated copper or nickel plated cadmium copper alloy, and an insulating layer comprising an extruded primary insulation layer 3 formed from ethylene tetrafluoroethylene copolymer (ETFE) and an extruded primary jacket 4 also formed from ETFE.
  • the primary insulation 3 will typically be 100 ⁇ m. thick while the primary jacket 4 will typically be 125 ⁇ m thick.
  • the primary jacket also includes a small quantity of carbon pigment to colour it black.
  • a 20 ⁇ m thick top layer 5 also formed from ETFE and containing 15% by weight titanium dioxide (based on the total weight of the top layer) is coextruded an the primary jacket.
  • the wire is subjected to a crosslinking step in which the primary insulation 3 and primary jacket 4 are crosslinked by high energy electrons.
  • the top layer remains substantially uncrosslinked since it contains no crosslinking promoter.
  • the wire has a white appearance due to the titanium dioxide in the top layer, and can be marked using a CO 2 laser to remove a portion 6 of the top layer corresponding to the mark and thereby expose a part of the underlying primary jacket 4.
  • the wire exhibits significantly improved arc tracking resistance over wires based on polyimide wrap PTFE wrap combinations and wires based solely on crosslinked ETFE layers.

Landscapes

  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Organic Insulating Materials (AREA)
  • Insulated Conductors (AREA)

Abstract

Un câble électrique comprend un conducteur électrique (2) ainsi qu'une isolation électrique basée presque entièrement sur une ou plusieurs couches de fluoropolymère extrudées (3 et 4). Le câble comprend une couche supérieure (5) d'une épaisseur ne dépassant pas 50mum, et qui contient une certaine quantité d'un additif qui supprime le cheminement d'arc, par exemple du dioxyde de titane ou du silice.
EP92920527A 1991-10-01 1992-09-30 Cable electrique Withdrawn EP0606319A1 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
GB919120917A GB9120917D0 (en) 1991-10-01 1991-10-01 Transmission line
GB9120917 1991-10-01
GB929206164A GB9206164D0 (en) 1992-03-16 1992-03-16 Electrical wire
GB9206164 1992-03-16
PCT/GB1992/001789 WO1993007627A1 (fr) 1991-10-01 1992-09-30 Cable electrique

Publications (1)

Publication Number Publication Date
EP0606319A1 true EP0606319A1 (fr) 1994-07-20

Family

ID=26299625

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92920527A Withdrawn EP0606319A1 (fr) 1991-10-01 1992-09-30 Cable electrique

Country Status (5)

Country Link
EP (1) EP0606319A1 (fr)
CA (1) CA2120513A1 (fr)
GB (1) GB9120917D0 (fr)
IL (2) IL103307A (fr)
WO (2) WO1993007628A1 (fr)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5259060A (en) * 1992-08-11 1993-11-02 Corning Incorporated Coated optical fibers and method
KR100520969B1 (ko) * 1997-07-18 2005-10-17 피렐리 카비 에 시스테미 소시에떼 퍼 아찌오니 높은 트래킹 저항을 갖는 광섬유 케이블
FR3002076B1 (fr) * 2013-02-12 2022-11-11 Nexans Cable electrique resistant aux decharges partielles
US10256009B2 (en) 2014-06-19 2019-04-09 Saint-Gobain Performance Plastics Corporation Laser-markable insulation material for wire or cable assemblies
US9881714B2 (en) 2014-06-19 2018-01-30 Saint-Gobain Performance Plastics Corporation Laser-markable insulation material for wire or cable assemblies
US9728298B2 (en) 2015-06-26 2017-08-08 Daikin America, Inc. Radiation crosslinked fluoropolymer compositions containing low level of extractable fluorides
CN108780201A (zh) * 2016-02-19 2018-11-09 通用线缆技术公司 激光可标记的线缆和用于制造其的系统
US11763962B2 (en) 2017-12-20 2023-09-19 Junkosha Inc. Cable
CN111492445B (zh) * 2017-12-20 2022-04-08 株式会社润工社 电缆

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2555799B1 (fr) * 1983-11-25 1987-04-17 Filotex Sa Cable electrique, notamment pour usage aerospatial, a caracteristiques electriques ameliorees
US4716073A (en) * 1986-06-02 1987-12-29 E. I. Du Pont De Nemours And Company Thin wall high performance insulation on wire
FR2648270A1 (fr) * 1989-06-09 1990-12-14 Fileca Sa Cable a revetement marquable par laser
FR2656734B1 (fr) * 1990-01-03 1992-03-20 Filotex Sa Cable electrique ou a fibres optiques marquable par plusieurs types de lasers.

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9307627A1 *

Also Published As

Publication number Publication date
GB9120917D0 (en) 1991-11-13
IL103307A0 (en) 1993-05-13
CA2120513A1 (fr) 1993-04-15
WO1993007628A1 (fr) 1993-04-15
IL103308A0 (en) 1993-05-13
IL103307A (en) 1996-01-31
WO1993007627A1 (fr) 1993-04-15

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