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
• • 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
• • 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
  • H01B7/29—Protection against damage caused by extremes of temperature or by flame
  • H01B7/295—Protection against damage caused by extremes of temperature or by flame using material resistant to flame

Definitions

• operably is used herein to include a single electrically insulated elongate conductor often referred to in the art as "wire"), an article comprising a plurality of separate elongate conductors each of which is separately insulated, and an article comprising a plurality of elongate conductors which are physically joined together but electrical.ly insulated from each other by insulating material, e.g. ribbon cable.
• Fluorocarbon polymers especially ethylene/tetrafluoroethylene (ETFE) copolymers such as Tefzel, are used extensively for electrical insulation, in particular for aircraft wire. Particularly when cross-linked, such polymers can exhibit an excellent combination of physical and electrical properties under normal service conditions.
• EFE ethylene/tetrafluoroethylene
• Tefzel ethylene/tetrafluoroethylene copolymers
• U.S. Patents Nos. 3,580,829, 3,738,923, 3,763,222, 3,840,619, 3,894,118, 3,911,192, 3,947,525, 3,970,770, 3,985,716, 3,995,091, 4,031,167, 4,155,823, 4,121,001, and 4,176,027 Other polymers which have been used for electrical insulation include other olefin polymers (both homopolymers and copolymers) and various high-melting aromatic polymers.
• the olefin polymer forming the inner layer preferably has a tensile (Young's) modulus of at least 138 MPa (20,000 p.s.i.) especially at least 207 MPa (30,000 p.s.i.) and particularly at least 276 MPa (40,000 p.s.i.) in order to minimize wrinkling of the outer layer when the article, e.g. in the form of a wire, is bent.
• a tensile (Young's) modulus of at least 138 MPa (20,000 p.s.i.) especially at least 207 MPa (30,000 p.s.i.) and particularly at least 276 MPa (40,000 p.s.i.) in order to minimize wrinkling of the outer layer when the article, e.g. in the form of a wire, is bent.
• the insulation of the article to the invention provides a valuable combination of physical and electrical properties.
• the outer layer provides excellent resistance to. physical abuse.
• the inner layer is more flexible than the outer layer and thus provides insulation which is more flexible, for a particular dielectric strength, than insulation which is composed only of the aromatic polymer.
• the-aromatic polymers often have poor resistance to stress-cracking which can seriously reduce their dielectric strength, the olefin polymers do not suffer from this disadvantage, and the inner jacket will' therefore provide continuous insulation even in environments which cause stress-cracking of the outer jacket.
• olefin polymer as used herein is defined as being a polymer of one or more unsubstituted and/or substituted olefins. Where the polymer includes substituted olefins as monomers or comonomers they are preferably polar monomers and especially fluorine-containing monomers, e.g. tetrafluorethylene, or a carboxylic ester, in particular an alkyl acrylate, e.g. methyl or ethyl acrylate, or a vinyl ester, e.g. vinyl acetate.
• the olefin is preferably a fluorcarbon polymer as explained below.
• the inner layer is composed of a cross-linked fluorocarbon layer.
• electrical wire which, when tested for smoke evolution by ASTM E 662-79 (flaming mode), has a D m value of less than 50, preferably less than 35, where D m is the maximum specific optical density.
• fluorocarbon polymer is used herein to denote a polymer or mixture of polymers which 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 of more fluorine-containing polymers with one or mere polymers which do not contain fluorine.
• the fluorocarbon polymer comprises at least 50%, particularly at least 75% especially 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 fluorocarbon 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 unsaturated 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 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 tetrafluoro-ethylene 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 tetrafluoro- ethylene and hexafluoropropylene.
• Either or both of the inner and outer insulating layers can optionally contain suitable additives such as pigments, antioxidants, thermal stabilisers, acid acceptors and processing aids.
• Such polymers include polyketones, polyether ketones, polyether ether ketones and polyether sulfones, polyether ketone/ sulfone copolymers and polyether imides. Blends of different polymers can be used.
• Preferred aromatic polymers are crystalline polymers with a melting point of at least 250°C, particularly at least 300°C.
• the polymer comprises, and preferably consists essentially of, units of the formula the units being the same or different, Ar being a divalent aromati-c radical and Q being -O-, -S-, -SO 2 -, -CO-, -NH-CO- or -COO-, or Ar being a polyvalent radical and Q being the Q radical preferably being directly bonded to aromatic carbon atoms in the Ar radical.
• the aromatic polymer is a crystalline polyarylene ether comprising recurring units of the formula where E is the residue of a dihydric phenol and E' is the residue of an aromatic compound having an electron withdrawing group in at least one of the positions ortho and para to the valence bonds, the E and E' radicals being linked to the -0- radicals through aromatic carbon atoms.
• E is a radical of the formula wherein R is a divalent radical; x is 0 or 1; Y is a radical selected from halogen atoms, alkyl radicals.
• R' is a radical selected from halogen atoms, alkyl radicals containing 1 to 4 carbon atoms and alkoxy radicals containing 1 to 4 carbon atoms; z is 0, 1, 2, 3 or 4, and E' is a radical of the formula wherein R' is a sulfone, carbonyl, vinyl, sulfoxide, azo, saturated fluorocarbon, organic phosphine oxide or ethylidene radical.
• polysulfones are those in which y and z are 0, x is 1, R' is a sulfone radical and R is a radical of the formula wherein each of R'' and R''' is independently selected from the group consisting of hydrogen; alkyl radicals containing 1 to 4 carbon atoms; halogen-substituted alkyl radical containing 1 to 4 carbon atoms; aryl, alkaryl and aralkyl radicals containing 6 to 10 carbon atoms; and halogen-substituted aryl alkaryl and aralkyl radicals containing 6 to 10 carbon atoms.
• the polymer is a polyether imide or polysulfone imide which comprises recurring units of the formula where Q is -O- or -SO 2 , Z is a trivalent aromatic radical, R is a divalent aromatic radical and R' is a divalent organic radical.
• Preferred aromatic polymers consist essentially of repeating units having one of the following formulae wherein each of x, m and n is 0 or 1, with n beinq 0 when x. is 1, p is an integer from 1 to 4, with m being 1 and x being 0 when p is greater than 1, e.g.,
• the insulated articles of the present invention can be produced by conventional techniques; the inner layer usually contacts the conductor, and the inner and outer layers generally constitute the total insulation of the article; however, other insulating layers can be present.
• the olefin polymer is preferably cross-linked by radiation, and cross-linking can be effected before or after the aromatic polymer (which is generally not cross-linked by radiation) is applied.
• the inner layer will usually be of annular cross-section of thickness for example 76.2 to 381 micrometres (3 to 15 mils), preferably 101.6 to 177.8 micrometres (4 to 7 mils).
• the cable can comprise a plurality of conductors, each of which has an inner insulating layer around it, with the conductors being joined together and further insulated by the outer insulating layer.
• the invention is illustrated by the following Examples, Examples 1, 2, 3 and 8 of which are comparative.
• a 20 AWG stranded (19/32) conductor was extrusion-coated with an inner insulating layer having the composition and thickess shown in the Table. Except in Examples 1 and 2, the inner insulating layer was then extrusion-coated with an outer insulating layer having the composition and thickness shown in the Table.
• the coated conductor was irradiated to a dosage of about 10 Megarads to cross-link the inner coating; in these Examples, the inner coating also contained, when it was irradiated, a suitable amount of a radiation cross-linking agent.
• the outer coating was substantially unaffected by this irradiation.
• the coated conductor was annealed at 180°C for 1 hour.
• Tefzel 280 is a copolymer of ethylene and tetrafluoro- ethylene available from du Pont.
• Halar 300 is a copolymer of ethylene and chlorotrifluoroethylene available from Allied Chemical.
• Kynar 450 is polyvinylidene fluoride available from Pennwalt.
• PEEK is a polyether ether ketone available from ICI.
• Ultem is a polyetherimide available from General Electric.
• Victrex 200P a polyethersulphone available from ICI.
• PEEK, Ultem and PES are substantially linear aromatic polymers.

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• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Organic Insulating Materials (AREA)
• Insulated Conductors (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Polymers With Sulfur, Phosphorus Or Metals In The Main Chain (AREA)

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• 1983
  • 1983-09-14 AT AT83305380T patent/ATE21462T1/de not_active IP Right Cessation
  • 1983-09-14 GB GB08324662A patent/GB2127210B/en not_active Expired
  • 1983-09-14 JP JP58170544A patent/JPS5973807A/ja active Granted
  • 1983-09-14 EP EP83305380A patent/EP0103487B1/de not_active Expired
  • 1983-09-14 CA CA000436688A patent/CA1214528A/en not_active Expired
  • 1983-09-14 DE DE8383305380T patent/DE3365309D1/de not_active Expired

Patent Citations (3)

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