EP0368886A1 - Fil - Google Patents

Fil

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Publication number
EP0368886A1
EP0368886A1 EP88905968A EP88905968A EP0368886A1 EP 0368886 A1 EP0368886 A1 EP 0368886A1 EP 88905968 A EP88905968 A EP 88905968A EP 88905968 A EP88905968 A EP 88905968A EP 0368886 A1 EP0368886 A1 EP 0368886A1
Authority
EP
European Patent Office
Prior art keywords
wire
polymer
layer
electrical
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.)
Withdrawn
Application number
EP88905968A
Other languages
German (de)
English (en)
Inventor
Richard John Penneck
Stephen Day
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 GB878716311A external-priority patent/GB8716311D0/en
Priority claimed from GB878716307A external-priority patent/GB8716307D0/en
Application filed by Raychem Ltd filed Critical Raychem Ltd
Publication of EP0368886A1 publication Critical patent/EP0368886A1/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Withdrawn legal-status Critical Current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
    • 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
    • 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
    • H01B3/42—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 polyesters; polyethers; polyacetals
    • H01B3/421—Polyesters
    • H01B3/422—Linear saturated polyesters derived from dicarboxylic acids and dihydroxy 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
    • H01B7/17—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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A30/00—Adapting or protecting infrastructure or their operation
    • Y02A30/14—Extreme weather resilient electric power supply systems, e.g. strengthening power lines or underground power cables

Definitions

  • This invention relates to electrical wires, and especially to wires that employ electrical insulation based on aromatic polymers.
  • aromatic polymer insulation have been used for many years in numerous applications.
  • wires that employ polyimide wraps or tapes usually bonded with fluoro- polymer adhesive layers have been used extensively as aircraft wire, for both civil and military applications.
  • Other examples of aromatic insulation that have been used for equipment wire or "hook-up" wire, air frame wire and in wire harnesses include aromatic polyether ketones, polyether ether ketones, modified polyphenylene oxide, and polyimide amides.
  • Highly aromatic polymers have been used successfully in many applications because they have a range of desirable properties especially high strength and toughness, abrasion resistance, temperature resistance, dielectric strength and are often inherently highly flame- retarded.
  • 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 e.g. 100V a.c. or less but becomes less likely as the voltage is reduced.
  • a related phenomenon, to which these polymers are also highly susceptible, is that of breakdown due to arcing.
  • 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 con- ductors 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 d.c. 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.
  • insulating material is removed by a vaporization process originated by an electrical discharge without the formation of electrically conductive deposits so that failure of the insulation will not occur until complete puncture of the insulation occurs .
  • an electrical wire which comprises an elongate electrical conductor and electrical insulation that comprises:
  • an inner insulating layer which comprises a polyester that has both aromatic and aliphatic moieties and has a molar carbon to hydrogen ratio of not more than 1.15;
  • an outer insulating layer which comprises a fluorinated polymer.
  • the invention has the advantage that it enables a wire to be formed that has a balance of properties such as solvent resistance, scrape abrasion resistance, toughness, weight and ability to strip in addition to very high resistance to tracking and arcing.
  • the polyester preferably has a molar carbon to hydrogen ratio of not more than 1.1 and especially not more than 1.0. This will normally correspond to a carbonaceous char residue of not more than 15%, preferably not more than 10%, most preferably not more than 5%, especially not more than 2% and most especially substantially 0% by weight.
  • the char residue of the polymer components in the electrical wire according to the invention can be measured by the method known as thermogravimetric analysis, or TGA, in which a sample of the polymer is heated in nitrogen or other inert atmosphere at a defined rate, e.g. 10oC per minute to a defined temperature and the residual weight, which is composed of char, is recorded.
  • TGA thermogravimetric analysis
  • the char residue is simply the quantity of this residual char expressed as a percentage of the initial polymer after having taken into account any non polymeric volatile or non-volatile components.
  • the char residue values quoted herein are defined as having been measured at 850oC.
  • the polyesters that are used for layer (a) preferably include those based on a polyalkylene diol, preferably having a least 3 carbon atoms, or a cyclo- aliphatic diol and an aromatic dicarboxylic acid.
  • Preferred polyesters include polytetramethylene terephthalate, and cycloaliphatic diol/terephthalic acid copolymers e.g. copolymers of terephthalate and isophthalate units with 1,4-cyclohexanedimethyloxy units.
  • the polyesters can include polyether esters, for example polyether polyester block copolymers having long chain units of the general formula: it I -OGO-C-R-C-
  • G is a divalent radical remaining after the removal of terminal hydroxyl groups from a polyalkylene oxide) glycol, preferably a poly (C 2 to C 4 alkylene oxide) having a molecular weight of about 600 to 6000;
  • R is a divalent radical remaining after removal of carboxyl groups from at least one dicarboxylic acid having a molecular weight of less than about 300;
  • D is a divalent radical remaining after removal of hydroxyl groups from at least one diol having a molecular weight less than 250.
  • copolyesters are the polyether ester polymers derived from terephthalic acid, polytetramethylene ether glycol and 1,4-butane diol. These are random block copolymers having crystalline hard blocks with the repeating unit: and amorphous, elastomeric polytetramethylene ether terephthalate soft blocks of repeating unit
  • n 6 to 40.
  • the polyester may be blended with one or more other polymers.
  • the polyesters may be used as blends with polyamides, polyolefins such as polyethylene, ethylene ethyl acrylate copolymers styrene/diene block copolymers or ionomers.
  • the fluorinated polymer used in layer (b) preferably contains more than 10%, preferably more than 25%, by weight of fluorine.
  • the fluorocarbon polymer may be a single fluorine-containing polymer, a mixture of two or more fluorine-containing polymers, or a mixture of one or more fluorine-containing polymers with one or more polymers which do not contain fluorine.
  • the fluorocarbon polymer comprises at least 50%, particularly at least 75% espcially at least 85%, by weight of one or more thermoplastic crystalline polymers each containing at least 25% by weight of fluorine, a single such crystalline polymer being preferred.
  • Such a fluoro- carbpn polymer may contain, for example, a fluorine- containing elastomer and/or a polyolefin, preferably a crystalline polyolefin, in addition to the crystalline fluorine-containing polymer or polymers.
  • the fluorine- containing polymers are generally homo- or copolymers of one or more fluorine-containing olefinically unsa- turated monomers, or copolymers of one or more such monomers with one or more olefins.
  • the fluorocarbon polymer usually has a melting point of at least 150°C, and will often have a melting point of at least 250°C, e.g.
  • the melting point being defined for crystalline polymers as the temperature above which no crystallinity exists in the polymer (or when a mixture of crystalline polymers is used, in the major crystalline component in the mixture).
  • the polymeric composition, prior to cross-linking has a viscosity of less than 10 4 Pa.s (10 5 poise) at a temperature not more than 60°C above its melting point.
  • a preferred fluorocarbon polymer is a copolymer of ethylene and tetrafluoroethylene and optionally one or more other comonomers (known as ETFE polymers), especially a copolymer comprising 35 to 60 mole percent of ethylene, 35 to 60 mole percent of tetrafluoroethylene and up to 10 mole percent of one or more other comonomers.
  • ETFE polymers comonomers
  • polymers which can be used include copolymers of ethylene and chlorotrifluoroethylene; polyvinylidene fluoride; copolymers of vinylidene fluoride with one or both of hexafluoropropylene and tetrafluoroethylene, or with hexafluoroisobutylene; and copolymers of tetrafluoroethylene and hexafluoropropylene.
  • C 1 -C 5 perfluoroalkoxy substituted perfluoroethylene homopolymers and copolymers with the above fluorinated polymers may be used.
  • the wire insulation, or at least the outer layer may be cross-linked, for example, by exposure to high energy radiation.
  • Radiation cross-linking may be effected by exposure to high energy irradiation such as an electron beam or gamma-rays. Radiation dosages in the range 20 to 800 kGy, preferably 20 to 500 kGy, e.g. 20 to 200 kGy and particularly 40 to 120 kGy are in general appropriate depending on the characteristics of the polymer in question.
  • a prorad such as a polyfunctional vinyl or allyl compound
  • a prorad such as a polyfunctional vinyl or allyl compound
  • TAIC triallyl isocyanurate
  • methylene bis acrylamide, metaphenylene diamine bis maleimide or other crosslinking agents for example as described in U.S. patents Nos. 4,121,001 and 4,176,027, are incorporated into the composition prior to irradiation.
  • the insulation may include additional additives, for example reinforcing or non-reinforcing fillers, stabilisers such as ultra-violet stabilisers, antioxidants, acid acceptors and anti-hydrolysis stabilisers, pigments, processing aids such as plasticizers, halogenated or non-halogenated flame retardants e.g. hydrated metal oxides such as alumina trihydrate or magnesium hydroxide, or decabromodiphenyl ether, fungicides and the like.
  • stabilisers such as ultra-violet stabilisers, antioxidants, acid acceptors and anti-hydrolysis stabilisers
  • pigments processing aids such as plasticizers
  • halogenated or non-halogenated flame retardants e.g. hydrated metal oxides such as alumina trihydrate or magnesium hydroxide, or decabromodiphenyl ether, fungicides and the like.
  • the wire insulation will consist solely of the polyester inner layer and the fluoropo lymer outer layer.
  • one or more other layers may be present.
  • an additional inorganic arc-control layer may be provided directly on the conductor, formed for example by deposition of an inorganic material on the conductor.
  • a highly aromatic polymer layer may be provided between layers (a) and (b) in order to improve for example the high temperature properties of the insulation. Examples of such aromatic polymers are disclosed in our copending European application entitled "Electrical Wire" which is filed on even date herewith and claims priority from British application No. 8716306.
  • the wires and cables according to the invention may be formed by conventional techniques.
  • the polymers may be blended with any additional components, in a mixer, pelletised, and then extruded onto a wire conductor.
  • Other wires may be formed by a tape- wrapping method although it is preferred for both the fluoropolymer and the polyester layers to be melt extruded.
  • the wires may be used individually as equipment or "hook-up" wires, or airframe wires, or in bundles and harnesses, both jacketted and unjacketted, and may be used in multiconductor cables.
  • the wires, harnesses or cables may be unscreened or they may be provided with a screen to protect them from electromagnetic interference, as well known in the art.
  • flat cables may be formed using the insulation materials according to the invention, either employing flat conductors or round conductors.
  • Figure 1 is an isometric view of part of an electrical wire according to the invention.
  • Figure 2 is a schematic view of the test arrangement for wet tracking.
  • Figure 3 is a schematic view of the test arrangement for dry arcing.
  • an electrical wire comprises a conductor 11 which may be solid or stranded as shown and is optionally tinned.
  • an inner insulating layer 12 (primary insulation) has been extruded.
  • the insulation is formed from polybutylene terephthalate which contains about 5% by weight triallyl isocyanurate crosslinking promoter.
  • an outer layer 13 (primary jacket) formed from an ethylene-tetrafluoroethylene copolymer, containing about 7% by weight triallyl isocyanurate crosslinking promotor, is extruded on the inner layer 12.
  • Each layer has a wall thickness of about 100 ⁇ m. After both layers have been extruded the insulation is irradiated by high energy electrons to a dose of about 120 kGy.
  • This test is designed to simulate the condition occuring when a damaged wire bundle comes into contact with an electrolyte.
  • the electrolyte may be moisture containing dust particles or other ionic contaminant. Damage to the bundle may occur through a number of reasons e.g. abrasion, hydrolysis of the insulation, ageing, etc.
  • Current flow through the electrolyte results in heating and evaporation of the solution. This causes one or more dry bands to appear across which the test voltage is dropped, resulting in small, often intense, scintillations which damage the insulation.
  • Figure 1 shows the sample set-up.
  • a wire bundle 1 is prepared from seven 18cm lengths 2 of 20AWG tinned- copper conductor coated with a layer of the material under test.
  • the bundle 1 is arranged with six wires around one central wire and is held together using tie wraps 3 so that the wires are not twisted.
  • Two adjacent wires are notched circumferentially to expose 0.5mm bare conductor on each wire.
  • the notches 4 are arranged such that they are 5mm apart with the tie wraps 5mm either side of them.
  • One end of each wire is stripped to enable connections to be made to the power supply via insulated crocodile clips.
  • the sample is held at an angle of 30 degrees to the horizontal using a simple clamp made of an electrically insulating resin so that the damaged wires are uppermost and the stripped ends are at the upper end of the bundle.
  • a piece of filter paper 5 20 x 10mm wide is wrapped around the bundle approximately 2mm above the upper notch; this is best held in place with the upper tie wrap.
  • a peristaltic pump conveys the electrolyte from the reservoir to the sample via a dropping pipette 6, and a power supply is provided to energise the bundle.
  • the electrolyte used is 2% sodium chloride and optionally 0.02% in ammonium perfluoroalkyl carboxylate surfactant in distilled or deionised water.
  • the pump is set to deliver this solution at a rate of approximately lOOmg per minute through the pipette 6 which is positioned 10mm vertically above the filter paper 5.
  • the power is supplied by a 3-phase 400Hz 115/200V generator of at least 5kVA capacity or a single phase 50Hz 115V transformer of at least 3kVA capacity.
  • a device for recording time to failure is provided which records the time when either a wire goes open circuit, or when a circuit breaker comes out. Leakage currents can be followed with the use of current clamps surrounding the wires and connected to a suitable oscilloscope.
  • adjacent wires of the bundle are connected to alternate phases of the power supply via 7.5A aircraft-type circuit breakers e.g. Klixon with the central wire connected directly to neutral.
  • alternate wires are connected to neutral with the remaining wires including the central conductor to live.
  • a few drops of electrolyte are allowed to fall onto the filter paper to ensure saturation prior to starting the test.
  • the power is switched on and the timer started. The test is allowed to continue until: a) one or more circuit breakers come out; b) a wire becomes open circuit; or c) 8 hours have elapsed.
  • failure due to the wire becoming open circuit is indicative of erosion. If failure occurs due to one or more circuit breakers coming out (result (a)) then the absence of further crepitation on resetting of the circuit breakers indicates failure due to erosion, while further crepitation indicates tracking failure.
  • FIG. 1 shows the sample set-up.
  • a wire bundle 21 is prepared from seven 10cm lengths 22 of 20AWG tinned-copper conductor coated with a layer of the wire insulation under test.
  • the bundle 22 is arranged with six wires around one central wire and held together with tie wraps spaced about 5cm apart. One of the outer wires is notched circumferentially between the tie wraps to expose 0.5mm bare conductor and one end of each wire is stripped to enable connections to be made via insulating crocodile clips.
  • a rod 23 is provided which is made of a spectrographically pure graphite, diameter 4.6mm, with an impurity level not more than 20ppm. It is prepared before each test by sharpening one end using a conventional pencil sharpener of European design to give an angle of 10 degrees off vertical with a tip diameter of 0.4 ⁇ 0.1mm.
  • a 100g weight 24 is clamped onto the top of the rod 23 to maintain contact during the arc initiation and also acts as a device to limit the depth of penetration of the rod by restricting its downward travel.
  • the rod passes through a PTFE bush which allows it to slide freely up and down.
  • levers enables precise positioning of the rod 23 on the wire bundle 21 which is held securely in place by means of a simple clamp 25 made of an electrically insulating resin and mounted on a block 26 made of the same material.
  • the power source can be either:
  • the fault current is detected by means of current clamps surrounding the connecting leads and the voltage at failure is measured using a 10:1 voltage probe.
  • the transducer signals are fed into a multi-channel digital storage oscilloscope where they can be displayed and manipulated to obtain power curves (voltage x current) and energy (integration of power curve).
  • the wire bundle 21 is positioned in the clamp 25 so that the notched wire is uppermost. Adjacent wires of the bundle are connected to different phases of the supply through 7.5A aircraft type circuit breakers, and the central wire is connected directly to neutral. In the case of single phase or d.c. supplies, alternate wires are connected to neutral or the negative terminal, with the remaining wires, including the central wire, connected through circuit breakers to live or the postive terminal.
  • the carbon rod is also connected to neutral or the negative terminal and positioned so that the point is in contact with the exposed conductor.
  • the gap between the 100g weight and the PTFE bush is adjusted to 0.4 mm using a suitable spacer to limit the penetration of the rod into the sample.
  • a voltage probe is connected across the damaged wire and the rod, and current clamps positioned on each of the three phases, or on the wires connected to the live side of the supply.
  • a protective screen is placed in front of the test set-up and the power switched on. A material is deemed to pass this test if: a) no circuit breakers come out and the activity is relatively non-eventful, or b) there is no further activity on resetting the breakers after a non-eventful test.
  • non-tracking materials will have relatively few spikes in the current trace with a correspondingly low total energy consumed.
  • Tracking materials show many spikes usually on all three phases, which are accompanied by violent crepitation and large energy consumption.
  • 20 AWG tinned copper conductors were provided with an extruded dual-wall insulation of approximately 100 micrometres wall thickness for each layer by means of a 20 mm Baughan extruder.
  • the inner layer contained approximately 5% by weight triallyl isocyanurate crosslinking promotor while the outer layer contained approximately 7% triallyl isocyanurate.
  • the wire was irradiated with high energy electrons to a dose of approximately 120 kGy in order to crosslink the insulation.
  • the ultimate elongation, tensile strength, 125oC cut through resistance, wet tracking and dry arcing were measured, and the results are shown in the Table.
  • Blends of polybutylene terephthalate with the ionomer contained 80% PBT, 20% ionomer, and blends with the butylene ether/butylene terephthalate copolymer (BEST) contained 70% PBT, 30% BEBT. All percentages given are by weight.

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

Abstract

Un fil électrique comprend un conducteur électrique allongé et un isolant électrique qui comporte: (a) une couche isolante interne contenant un polyester ayant des parties aromatiques et aliphatiques et un rapport molaire carbone/hydrogène qui n'est pas supérieur à 1,15, tel que le téréphtalate de polybutylène; et (b) une couche isolante externe qui contient un polymère fluoré. Ledit fil présente des propriétés électriques et mécaniques bien équilibrées ainsi qu'une résistance élevée au cheminement à l'état humide et à la formation d'arc à sec.
EP88905968A 1987-07-10 1988-07-08 Fil Withdrawn EP0368886A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB8716311 1987-07-10
GB8716307 1987-07-10
GB878716311A GB8716311D0 (en) 1987-07-10 1987-07-10 Wire
GB878716307A GB8716307D0 (en) 1987-07-10 1987-07-10 Electrical wire

Publications (1)

Publication Number Publication Date
EP0368886A1 true EP0368886A1 (fr) 1990-05-23

Family

ID=26292467

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88905968A Withdrawn EP0368886A1 (fr) 1987-07-10 1988-07-08 Fil

Country Status (5)

Country Link
EP (1) EP0368886A1 (fr)
JP (1) JPH02504091A (fr)
CA (1) CA1307837C (fr)
IL (1) IL87049A0 (fr)
WO (1) WO1989000759A1 (fr)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6087591A (en) * 1995-04-26 2000-07-11 Nguyen; Phu D. Insulated electrical conductors
WO1996035216A1 (fr) * 1995-05-04 1996-11-07 Raychem Corporation Compositions elastomeres thermoplastiques et conducteurs electriques isoles
GB0006333D0 (en) * 2000-03-16 2000-05-03 Raychem Ltd Electrical wire insulation
JP2003036730A (ja) * 2001-07-24 2003-02-07 Ricoh Co Ltd 電子機器のワイヤハーネス
BRPI1008923A2 (pt) 2009-02-27 2016-03-15 Tyco Electronics Corp condutor isolado de múltiplas camadas com camada externa reticulada

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1177471A (en) * 1968-01-01 1970-01-14 British Insulated Callenders Improvements in Electric Cables.
DE3373039D1 (en) * 1982-10-01 1987-09-17 Raychem Ltd Electric wire with flame retarded cladding
GB8318612D0 (en) * 1983-07-08 1983-08-10 Raychem Ltd Wire and cable
GB8428982D0 (en) * 1984-11-16 1984-12-27 Raychem Ltd Polymer composition
IT1186156B (it) * 1985-12-20 1987-11-18 Pirelli Cavi Spa Cavo elettrico per basse tensione

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8900759A1 *

Also Published As

Publication number Publication date
JPH02504091A (ja) 1990-11-22
IL87049A0 (en) 1988-12-30
WO1989000759A1 (fr) 1989-01-26
CA1307837C (fr) 1992-09-22

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