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
  • H01B7/17—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
  • H01B7/292—Protection against damage caused by extremes of temperature or by flame using material resistant to heat
• • 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
  • H01B3/301—Macromolecular compounds obtained by reactions forming a linkage containing sulfur with or without nitrogen, oxygen or carbon in the main chain of the macromolecule, not provided for in group H01B3/302
• • 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
  • H01B3/303—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups H01B3/38 or H01B3/302
  • H01B3/306—Polyimides or polyesterimides
• • 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
  • H01B3/427—Polyethers
• • 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
  • H01B7/0208—Cables with several layers of insulating material

Definitions

• This invention relates to insulated wires and electric cables, all of which are hereinafter included in the term 'cables'.
• the cables of the invention are primarily, but not exclusively, suitable for aircraft wiring and other electronics purposes.
• KPA150 One of the more successful cables at present used in this market is the Applicants' "KPA150" cable.
• this cable two tapes of aromatic polyimide foil, each thinly coated on both sides with fluorinated ethylene-propylene copolymer as a bonding agent, are lapped on the conductor each overlapping by 67% (nominally) so that each tape forms three complete overlapping layers, and a pigmented lacquer is applied to give an abrasion-resistant coating that is receptive to printing.
• This cable is suitable for continuous service at 150 o C, and is generally satisfactory, though the slightly irregular surface has occasionally caused difficulties in sealing round the cable at terminations and may reduce the legibility of markings, and the fluorine and nitrogen contents may imply some toxic hazard under severe fire conditions.
• the present invention provides a cable which (i) has at least as good temperature rating; (ii) has a smooth surface; (iii) contains no, or at least substantially less, fluorine and substantially less nitrogen; (iv) is easier to manufacture and requires simpler plant; and ( v ) can be at least as low in weight and bulk at the "KPA150" cable (an important consideration as the weight of cables in a modern aircraft can be a significant fraction of the payload).
• the conventional type of tape coated with a bonding layer of fluorinated ethylene-propylene copolymer can be used, but this is not essential and the use of uncoated tape has the advantage of completely eliminating fluorine compounds from the cable.
• the tape is helically applied to the conductor, preferably with an overlap of at least 60%.
• the tape could be applied longitu- d inally or as a further alternative could be applied initially in a longitudinal direction and converted to a helical form by twisting the wrapped wire (before or after applying the outer layer) for example using a flyer-type winding machine (as conventionally used for twinning and bunching).
• the conductor may be solid or stranded and is preferably of plain, tinned, nickel-plated or silver-plated copper.
• the preferred polyimide for the tape is that sold under the trademark Kapton, which is believed to consist essentially of the polymeric pyromellitate of p,p' diamino diphenyl ether.
• Kapton is believed to consist essentially of the polymeric pyromellitate of p,p' diamino diphenyl ether.
• the tape is no more than 0.04mm thick and any coating thereon no more than 0.005mm thick. More especially Kapton 010 tape, an uncoated tape 0.025mm thick and Kapton 616 tape, a coated tape in which the polyimide is about 0.025mm thick and the coating about 0.0025mm thick, are preferred.
• Suitable polymers for the outer layer are described in British Patent Specifications 971,227, 1,016, 245, 1,019,266, 1,019,458, 1,078,234, 1,086,021, 1,102,679, 1,153,035, 1,153,527, 1,164,817, 1,177,183, 1,383,393, 1,387,303, and 1,414,421, 1,414,422 and 1.414.423 and in European Patent Application 0001879.
• Linear polymers are usually preferred, but some can be crosslinked, and this may sometimes be beneficial.
• Polymers in which the aromatic groups are predominately phenylene and the linking groups are selected from -0-, -CO- and -S0 2 - are preferred; most preferred are polyether ketones and polyether sulphones in which (in both cases) -0- linkages are in the majority, and more especially paraphenylene polyether ketones having about twice as many -0- linkages as -C0- linkages (such as the polymer sold by ICI as "PEEK").
• the outer layer is preferably extruded, either as a single operation or in two (or more) steps. Alternatively it might be in tape form applied helically or applied longitudinally with or without subsequent twisting; further it might be a composite layer applied partly in tape form and partly by extrusion (under, over or between tapes). When the outer layer is in two or more parts they may be of identical composition or they may differ within the range of polymers defined above.
• the outer layer is oriented, suitable techiniques for extruded layers being described in our British Patent Application 16614/78 and our European Application No. 79301544.7.
• Two or more wires, insulated as described, may be assembled together by twisting or otherwise to form a multiconductor cable, with or without a suitable overall sheath, braid or other coverings.
• the combined radial thickness of the polyimide tape layer and the outer layer is not more than 0.25mm.
• a single-conductor low-toxicity airframe cable consists of a conventionally stranded conductor made up of 19 silver plated annealed copper conductors each 0.20 mm in diameter lapped with a single tape of FEP-coated polyimide tape (Kapton 616Hf), 9.6 mm wide and applied with 67% overlap (nominal diameter over tape 1.18 mm), heat- sealed and then covered with 0.15 mm radial thickness of a polyphenylene ether-ketone (having about two ether linkages for each ketone linkage). This covering is applied by extrusion using a conventional thermoplastic extrude operating at 400°C, and raises the nominal overall diameter to 1.48 mm.
• the polyphenylene ether-ketone can be coloured with suitably-chosen pigments, if desired; other additives are unnecessary.
• Example 2 Two and three respectively of the conductors described in Example 1 are twisted together with a lay-length of 20 times pitch diameter, right handed.
• a braided 2-core aircraft-wiring cable consists of the cable of Example 2 braided with 0.10 mm diameter silver-plated annealed copper wires, 16 spindles 8 ends, 19 mm lay (nominal diameter over braid 3.46 mm) and sheathed to a radial thickness of 1.0 mm with an ethylene-acrylic polymer composition formulated as follows:
• Example 1 The single core of Example 1 is braided and sheathed substantially as described in Example 3.
• a thirty-core cable comprises conductors according to Example 6 laid up 4, 10 and 16 with the lay-length of each layer 20 times the respective pitch diameter, with a sheath (1.2 mm radial thickness) of the same formulation set out in Example 4.
• Example 11 This is similar to Example 11, but each core is the screened and sheathed conductor of Example 10.
• the cables of the Examples all have excellent radiation and water resistance; those of Examples 1-5 have good resistance to notch propagation, whereas the others have the merit of a substantially zero halogen content.

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Cited By (9)

Citations (5)

• 1981
  • 1981-05-05 EP EP81301965A patent/EP0040034A1/de not_active Withdrawn

Patent Citations (5)

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