WO2021201097A1 - Carbon nanotube-coated wire - Google Patents

Carbon nanotube-coated wire Download PDF

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Publication number
WO2021201097A1
WO2021201097A1 PCT/JP2021/013830 JP2021013830W WO2021201097A1 WO 2021201097 A1 WO2021201097 A1 WO 2021201097A1 JP 2021013830 W JP2021013830 W JP 2021013830W WO 2021201097 A1 WO2021201097 A1 WO 2021201097A1
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Prior art keywords
wire
carbon nanotube
cnt
conductor
coated
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PCT/JP2021/013830
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French (fr)
Japanese (ja)
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英樹 會澤
小泉　正治
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古河電気工業株式会社
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Priority to JP2022512620A priority Critical patent/JPWO2021201097A1/ja
Publication of WO2021201097A1 publication Critical patent/WO2021201097A1/en

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    • D—TEXTILES; PAPER
    • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
    • D02G—CRIMPING OR CURLING FIBRES, FILAMENTS, THREADS, OR YARNS; YARNS OR THREADS
    • D02G3/00—Yarns or threads, e.g. fancy yarns; Processes or apparatus for the production thereof, not otherwise provided for
    • D02G3/02—Yarns or threads characterised by the material or by the materials from which they are made
    • D02G3/16—Yarns or threads made from mineral substances
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/04—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of carbon-silicon compounds, carbon or silicon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B5/00—Non-insulated conductors or conductive bodies characterised by their form
    • H01B5/08—Several wires or the like stranded in the form of a rope
    • 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

Definitions

  • the present invention relates to a carbon nanotube-coated electric wire, and more particularly to a carbon nanotube-coated electric wire in which a carbon nanotube stranded wire is coated with a coating material exhibiting compressibility.
  • a coated electric wire composed of a conductor and an insulating coating covering the conductor is used.
  • a material for a wire rod constituting a conductor a metal wire such as copper or a copper alloy is usually used from the viewpoint of electrical characteristics.
  • Carbon nanotubes are materials having various properties and are expected to be applied to many fields. For example, carbon nanotubes are promising as materials for wire rods because they are lightweight and have excellent properties such as conductivity, thermal conductivity, and mechanical strength.
  • a stranded wire obtained by twisting each strand of the carbon nanotube wire rod is usually used in order to improve the strength of the electric wire.
  • the carbon nanotubes are fibrous strands, when the strands of the carbon nanotubes are twisted at a long pitch, the adhesion between the strands is lowered and the strands are easily untwisted. In this case, a gap may be formed between the wires, which may lead to a decrease in conductivity.
  • the number of twists is increased in order to prevent the untwisting from becoming easy, tension is applied to the carbon nanotube wire rod, which may cause quality deterioration due to disconnection. Therefore, it is necessary to fix the stranded carbon nanotube wire rod with a small number of twists and suppress the decrease in conductivity.
  • Patent Document 1 in a carbon nanotube wire provided with a plurality of carbon nanotube fibers formed only of carbon nanotubes and a pipe, the plurality of carbon nanotube fibers are firmly gripped from the outside by a pipe over the entire length direction. It is disclosed that it is stored in a pipe in a state.
  • the carbon nanotube fiber can be held by the pipe, when the outer periphery of the carbon nanotube wire as a conductor is further covered with a tubular metal pipe, the weight of the electric wire is equal to the weight of the added pipe. Will increase. Therefore, there is a problem that the weight of the carbon nanotube cannot be exhibited and the weight of the electric wire cannot be reduced. Further, when the carbon nanotube wire is coated with a resin pipe, the influence of conductivity due to the use of such a pipe is not mentioned.
  • An object of the present invention is to provide a carbon nanotube-coated electric wire having improved conductivity while taking advantage of the light weight of carbon nanotubes.
  • the carbon nanotube-coated electric wire according to the present embodiment includes a conductor and a compression coating layer covering the conductor, and the conductor is a carbon nanotube stranded wire in which a plurality of carbon nanotube strands are twisted, and the compression coating is provided.
  • the ratio (R1 / R2) of the resistance value R1 (m ⁇ / m) of the conductor after the compression coating layer is coated to the resistance value R2 (m ⁇ / m) of the conductor before the layer is coated is 0.96. Is less than.
  • the ratio ( ⁇ 1 / ⁇ 2) of the conductor diameter ⁇ 1 (mm) after the compression coating layer is coated to the conductor diameter ⁇ 2 (mm) before the compression coating layer is coated is determined. It is less than 0.95.
  • the diameter of the carbon nanotube strands is 150 ⁇ m or less, and the number of carbon nanotube strands is 20 or more.
  • the diameter of the carbon nanotube strands is 80 ⁇ m or less, and the number of carbon nanotube strands is 50 or more.
  • the number of twists of the carbon nanotube stranded wire is 50 T / m or more and 400 T / m or less.
  • the carbon nanotube-coated electric wire according to another embodiment of the present invention is a carbon nanotube stranded wire comprising a conductor and a compression coating layer covering the conductor, and the conductor is a stranded carbon nanotube wire in which a plurality of carbon nanotube strands are twisted.
  • the wire diameter of the carbon nanotube wire is 150 ⁇ m or less
  • the number of carbon nanotube wires is 20 or more
  • the number of twists of the carbon nanotube stranded wire is 80 T / m or more and 300 T / m or less.
  • the conductor diameter ⁇ 1 after the compression coating layer is coated is 1.3 mm or less.
  • the diameter of the carbon nanotube strands is 50 ⁇ m or less, and the number of carbon nanotube strands is 100 or more.
  • the compression coating layer is a heat shrinkable tube.
  • the carbon nanotube stranded wire is held by the compression coating layer having a flexural modulus of 500 MPa or more.
  • an insulating resin layer is further provided on the outer periphery of the compression coating layer.
  • the carbon nanotube-coated electric wire is used as a wire harness for an automobile.
  • the carbon nanotube-coated electric wire (hereinafter, may be referred to as “CNT-coated electric wire”) 1 according to the embodiment of the present invention is a carbon nanotube stranded wire as a conductor (hereinafter, “CNT stranded wire”.
  • the compression coating layer 20 for coating the CNT stranded wire 10 is provided, and the outer peripheral surface of the CNT stranded wire 10 is coated with the compression coating layer 20. That is, the compression coating layer 20 is coated along the longitudinal direction of the CNT stranded wire 10. In the CNT-coated electric wire 1, since the entire outer peripheral surface of the CNT stranded wire 10 is covered with the compression coating layer 20, the compression coating layer 20 is in close contact with the outer peripheral surface of the CNT stranded wire 10.
  • the CNT stranded wire 10 is formed of a carbon nanotube aggregate (hereinafter, may be referred to as “CNT aggregate”), and the CNT aggregate may be referred to as a carbon nanotube wire (hereinafter, “CNT wire”). .) Used as 11.
  • the CNT stranded wire 10 is formed by twisting a plurality of CNT strands 11.
  • the conductor diameter (diameter equivalent to a circle) of the CNT stranded wire 10 is not particularly limited, but is preferably 0.1 mm or more and 10 mm or less, for example.
  • the cross-sectional area of the CNT stranded wire 10 is preferably 0.005 mm 2 or more and 50 mm 2 or less.
  • the circle-equivalent diameter is obtained by calculating the cross-sectional area from the observation of the cross section of the CNT stranded wire 10 in the radial direction and calculating the diameter of the circle having the same area.
  • the CNT stranded wire 10 may be doped with a different element.
  • the CNT stranded wire 10 may be formed by twisting a plurality of carbon nanotube composites in which a dissimilar element is doped into the CNT strand 11.
  • Dissimilar elements include, for example, one or more elements or molecules selected from the group consisting of nitric acid, sulfuric acid, iodine, bromine, potassium, sodium, boron and nitrogen.
  • the CNT stranded wire 10 can be formed as a stranded wire by bundling a plurality of CNT strands 11 and fixing one end thereof, and twisting the other end a predetermined number of times.
  • the number of twists (twist degree) of the CNT stranded wire 10 is represented by the number of turns per unit length when a plurality of CNT strands 11 are twisted together. That is, the number of twists can be expressed by a value (unit: T / m) obtained by dividing the number of twists (T) by the length (m) of the wire.
  • the number of twists (T / m) of the CNT stranded wire 10 is preferably more than 0 T / m and 1000 T / m or less, preferably 50 T / m or more and 400 T / m or less, in order to impart a certain strength to the CNT stranded wire 10. Is more preferable. In particular, when the number of twists of the CNT stranded wire 10 is 80 T / m or more and 300 T / m or less, the strength can be improved and the twisting process can be simplified.
  • the CNT wire 11 is in direct contact with another adjacent CNT wire 11. Further, the CNT wire 11 is excellent in conductivity in the longitudinal direction. Since the CNT wire 11 is in direct contact with another adjacent CNT wire 11, the CNT stranded wire 10 exhibits excellent conductivity as a whole.
  • the CNT wire 11 used for the CNT-coated electric wire 1 is composed of a plurality of carbon nanotubes having a layer structure of one or more layers (hereinafter, may be referred to as “CNT”).
  • the CNT stranded wire 10 means a CNT wire having a CNT ratio of 70% by mass or more.
  • plating and dopants are excluded in the calculation of the CNT ratio in the CNT stranded wire. Since the longitudinal direction of the CNT strand 11 forms the longitudinal direction of the CNT stranded wire 10, the CNT strand 11 is linear.
  • the CNT wire 11 is a bundle of long CNTs having a layered structure of one or more layers.
  • the longitudinal direction of the CNT forms the longitudinal direction of the CNT wire 11.
  • the wire diameter (diameter equivalent to a circle) of the CNT wire 11 is preferably 10 ⁇ m or more and 150 ⁇ m or less, and the lower limit of the wire diameter is more preferably 20 ⁇ m or more. Further, the upper limit of the wire diameter is more preferably 80 ⁇ m or less, and more preferably 50 ⁇ m or less.
  • the number of CNT strands 11 constituting the CNT stranded wire 10 is preferably 20 or more and 1000 or less, and the lower limit of the number of CNT strands 11 is more preferably 50 or more, more preferably 100.
  • the upper limit of the number of CNT strands 11 is 800 or less.
  • the wire diameter of the CNT wire 11 is 80 ⁇ m or less and the number of the CNT wire 11 is 50 or more, the effect of increasing the contact area of each CNT wire 11 by the compression coating is improved. Therefore, it is possible to obtain the CNT-coated electric wire 1 having further improved conductivity.
  • the wire diameter of the CNT wire 11 is 50 ⁇ m or less and the number of the CNT wire 11 is 100 or more, the CNT-coated electric wire 1 in which the above effect is remarkably obtained can be obtained.
  • the CNTs constituting the CNT wire 11 are tubular bodies having a single-walled structure or a multi-walled structure, and are called SWNTs (single-walled nanotubes) and MWNTs (multi-walled nanotubes), respectively.
  • the CNT wire 11 may be formed of either a CNT having a single-walled layer structure, a CNT having a two-layer structure, or a CNT having a three-layer structure or more, and these layer structures may be formed. It may be formed by using a plurality of CNTs having.
  • the CNT having a two-layer structure is a three-dimensional network structure in which two cylindrical bodies having a network structure of a hexagonal lattice are arranged substantially coaxially. It is called Double-walled nanotube).
  • the hexagonal lattice which is a constituent unit, is a six-membered ring in which carbon atoms are arranged at its vertices, and these are continuously bonded adjacent to other six-membered rings.
  • the properties of the CNTs constituting the CNT wire 11 depend on the chirality of the tubular body. Chirality is roughly classified into an armchair type, a zigzag type, and a chiral type.
  • the armchair type exhibits metallic behavior
  • the zigzag type exhibits semiconductor and semimetal properties
  • the chiral type exhibits semiconductor and semimetal properties. Therefore, the conductivity of CNTs differs greatly depending on which chirality the tubular body has.
  • compression coating layer 20 that covers the outer peripheral surface of the CNT stranded wire 10 used for the CNT-coated electric wire 1 will be described.
  • a heat-shrinkable material is used as the material of the compression coating layer 20.
  • a compression coating layer 20 is preferably a tubular body into which the CNT stranded wire 10 can be inserted, and more preferably a heat-shrinkable tube available on the market.
  • the compression coating layer 20 is a heat-shrinkable tube
  • the heat-shrinkable tube 10 is inserted into the heat-shrinkable tube and heated to shrink the heat-shrinkable tube, and the CNT stranded wire 10 has a compressive force. The coating is applied.
  • the adhesion between the CNT strands 11 is improved, and the twist of the CNT strands 11 is fixed.
  • the generation of gaps between the CNT strands 11 can be suppressed, and the decrease in conductivity of the CNT-coated electric wire 1 can be suppressed.
  • Examples of the material of the compression coating layer 20 include polytetrafluoroethylene, polyolefin, polyvinyl chloride, ethylene propylene rubber, silicone rubber, and the like, and the material before heating is used. These materials may be used alone or in admixture of two or more.
  • the force with which the compression coating layer 20 compresses the CNT stranded wire 10 is not particularly limited, but it can be adjusted depending on the material of the compression coating layer 20, the combination thereof, the heating temperature, the heating time, and the like.
  • the CNT stranded wire 10 can be appropriately compressed by adjusting so that the CNT stranded wire 10 is held by the compression coating layer 20 having a flexural modulus (after compression) of 500 MPa or more.
  • the flexural modulus is 500 MPa or more, the CNT stranded wire 10 is more reliably held via the compression coating layer 20, and the compression of the compression coating layer 20 can be maintained for a long period of time.
  • the upper limit of the flexural modulus is preferably 4000 MPa or less, more preferably 1000 MPa or less, and even more preferably 600 MPa or less. Since the upper limit of the flexural modulus is 4000 MPa or less, it is possible to prevent the CNT-coated electric wire 1 from becoming difficult to bend, and it is possible to easily perform processing in a subsequent process.
  • the flexural modulus of the resin can be measured by a method based on JIS K7171 (2016). Further, the flexural modulus of 500 MPa or more is such that the diameter of the CNT wire 11 is 150 ⁇ m or less, the number of the CNT wire 11 is 20 or more, and the number of twists of the CNT stranded wire 10 is 80 T.
  • An insulating resin layer may be further provided on the outer periphery of the compression coating layer 20.
  • the material of the insulating resin layer is not particularly limited as long as it is a generally used insulating resin. Further, the insulating resin layer is formed by a general processing method by extrusion coating, and a heated insulating resin is used as a coating material. That is, since a heated material is used for the insulating resin layer, the insulating resin layer does not heat shrink regardless of the resin material.
  • Examples of the material of such an insulating resin layer include polyvinylidene chloride, polyvinyl alcohol, polystyrene, polyethylene, polypropylene, polyacetal, polymethylmethacrylate, cellulose acetate, polycarbonate, polyethylene terephthalate, polyamide, polyamideimide, and polychlorotrifluoroethylene.
  • Examples thereof include polytetrafluoroethylene, polyvinylidene fluoride, styrene / acrylonitrile copolymer, styrene / butadiene / acrylonitrile copolymer, and enamel. These may be used alone, or two or more kinds may be appropriately mixed and used.
  • the insulation, shape retention, and weather resistance of the compression coating layer 20 can be enhanced. Further, since the insulating resin layer has good adhesion to the compression coating layer 20, the adhesive strength can be higher than that of coating the insulating resin layer on the CNT stranded wire 10.
  • the total thickness of the compression coating layer 20 and the insulating resin layer is not particularly limited, but is preferably 0.002 mm or more and 2 mm or less, and more preferably 0.005 mm or more and 1 mm or less.
  • the thickness of the compression coating layer 20 is not particularly limited, but is preferably 0.001 mm or more and 1.5 mm or less, and more preferably 0.0025 mm or more and 0.5 mm or less.
  • the diameter of the heat-shrinkable tube is preferably 1.05 to 1.5 times the conductor diameter of the CNT stranded wire 10.
  • the ratio R1 / R2 of m) is less than 0.96, preferably 0.9 or less, and more preferably 0.7 or less.
  • the volume resistivity of the conductor coated with the compression coating layer 20 is lower than that of the conductor before the compression coating layer 20 is coated. Therefore, the CNT-coated electric wire 1 having improved conductivity can be obtained. Further, the CNT stranded wire 10 can be fixed by the compression coating layer 20 without interposing another member such as a pipe. Further, in order to reduce the variation in the resistance value in the longitudinal direction, the lower limit of the ratio (R1 / R2) is preferably 0.3 or more.
  • the range of the resistance value R1 of the conductor is preferably 0.96 m ⁇ / m or more and 960 m ⁇ / m or less, and the range of the resistance value R2 of the conductor is, for example, more than 1 m ⁇ / m and 1000 m ⁇ / m or less. Is preferable.
  • the resistance values R1 and R2 of the conductor are measured by, for example, the four-terminal method.
  • the ratio ( ⁇ 1 / ⁇ 2) of the conductor diameter ⁇ 1 after the compression coating layer 20 is coated to the conductor diameter ⁇ 2 before the compression coating layer 20 is coated is 0.95. It is preferably less than, more preferably 0.9 or less, and even more preferably 0.85 or less.
  • the conductor diameter ⁇ 1 after the CNT stranded wire 10 is coated with the compression coating layer 20 as shown in FIG. 1 is the conductor diameter ⁇ 1 as shown in FIG. 2, and the CNT stranded wire 10 is the compression coating layer 20 as shown in FIG.
  • the ratio ( ⁇ 1 / ⁇ 2) is controlled so as to be smaller than the conductor diameter ⁇ 2 before being coated with.
  • the CNT stranded wire 10 is more reliably fixed by the compression coating layer 20, so that the adhesion between the CNT strands 11 is improved, and the conductivity is reduced due to the generation of gaps between the CNT strands 11. It can be suppressed.
  • the lower limit of the ratio ( ⁇ 1 / ⁇ 2) is preferably 0.7 or more in order to prevent the CNT strand wire from being broken due to an excessive compressive force applied to the CNT stranded wire 10.
  • the range of the conductor diameter ⁇ 1 is preferably 0.095 mm or more and 9.5 mm or less, and the lower limit of the conductor diameter ⁇ 1 is preferably 0.3 mm or more, more preferably 0.5 mm or more. ..
  • the upper limit of the conductor diameter ⁇ 1 is preferably 5.0 mm or less, and more preferably 1.3 mm or less.
  • the range of the conductor diameter ⁇ 2 is preferably 0.1 mm or more and 10 mm or less, and the lower limit of the conductor diameter ⁇ 2 is preferably 0.3 mm or more, more preferably 0.5 mm or more. ..
  • the upper limit of the conductor diameter ⁇ 2 is preferably 5.0 mm or less, and more preferably 1.5 mm or less.
  • the upper limit of the conductor diameter ⁇ 1 of 1.3 mm or less is that the wire diameter of the CNT wire 11 is 150 ⁇ m or less, the number of the CNT wire 11 is 20 or more, and the number of twists of the CNT stranded wire 10 is 20 or more.
  • the conductor diameters ⁇ 1 and ⁇ 2 can be obtained by calculating the circle-equivalent diameter from the cross-sectional area measured by, for example, observing the cross section with a microscope.
  • the CNT-coated electric wire 1 first prepares CNTs, and then prepares CNT strands 11 from the obtained plurality of CNTs. Next, the obtained plurality of CNT strands 11 are twisted together to produce a CNT stranded wire 10. After that, the CNT-coated electric wire 1 can be manufactured by coating the outer peripheral surface of the CNT stranded wire 10 with the compression coating layer 20.
  • CNT11 can be produced by, for example, a floating catalyst method (Patent No. 5819888), a substrate method (Patent No. 5590603), and the floating catalyst method is preferable.
  • the CNT wire 11 is, for example, dry spinning (Patent No. 5819888, Patent No. 5990202, Patent No. 5350635), wet spinning (Patent No. 5135620, Patent No. 5131571, Patent No. 5288359), liquid crystal spinning. It can be produced by a method such as (Japanese Patent Publication No. 2014-530964).
  • a method of coating by utilizing the heat shrinkage of the compression coating layer 20 can be used.
  • the CNT stranded wire 10 is inserted into the heat-shrinkable tube which is the material of the compression coating layer 20, and the heat-shrinkable tube is contracted by heating with a dryer or the like, so that the CNT stranded wire 10 is coated with the compression coating layer 20.
  • the CNT-coated electric wire 1 in the present embodiment can be used as an electric wire as a power line or a signal line in various fields such as automobiles, electric devices, and control devices.
  • the CNT-coated electric wire 1 is suitable for use as a wire harness for automobiles.
  • Example 1 to 4 and Comparative Examples 1 to 2 For Examples 1 to 4 and Comparative Examples 1 and 2, coated electric wires were produced by the following manufacturing steps.
  • ⁇ Measurement of conductor diameter> The conductor before the heat-shrinkable tube was coated was cut with a cutter to obtain a cross section, and the cross section of the conductor was determined by observing with a microscope. The diameter of a circle (diameter equivalent to a circle) having the same cross-sectional area was obtained, and the value was defined as a conductor diameter of ⁇ 2 (mm). Next, the conductor diameter of the conductor after the heat-shrinkable tube was coated was measured in the same manner, and the measured value was defined as the conductor diameter ⁇ 1 (mm). The ratio of conductor diameters ( ⁇ 1 / ⁇ 2) was calculated based on the obtained conductor diameters ⁇ 1 and ⁇ 2.
  • ⁇ Conductor resistance value> The resistance value of the front conductor covered with the heat-shrinkable tube when a current of 100 mA was passed was measured using a source meter (manufactured by Keithley), and the measured value was defined as R2 (m ⁇ / m). Next, the resistance value of the conductor after the heat-shrinkable tube was coated was measured in the same manner, and the measured value was set to R1 (m ⁇ / m). Based on the obtained resistance values R1 and R2, the ratio of the resistance values of the conductors (R1 / R2) was calculated.
  • the volume resistivity ⁇ 1 (m ⁇ ⁇ cm) after coating can be obtained from the following formula (1).
  • R1 is the resistance value (m ⁇ / m) per 1 m of the coated conductor
  • S1 is the cross-sectional area (cm 2 ) obtained from the microscope image of the cross section of the coated conductor.
  • the volume resistivity ⁇ 2 (m ⁇ ⁇ cm) before coating is obtained from the following equation (2).
  • R2 is the resistance value (m ⁇ / m) per 1 m of the conductor before coating
  • S2 is the cross-sectional area (cm 2 ) obtained from the microscope image of the cross section of the conductor before coating.
  • the ratio of volume resistivity ( ⁇ 1 / ⁇ 2) was calculated based on the obtained volume resistivityes ⁇ 1 and ⁇ 2.
  • the volume resistivity ratio ( ⁇ 1 / ⁇ 2) was 0.75 or less, it was evaluated that a CNT-coated electric wire having improved conductivity was obtained.
  • ⁇ 1 (R1 / 100) ⁇ S1 ...
  • ⁇ 2 (R2 / 100) ⁇ S2 ...
  • Table 1 below shows the measurement and evaluation results of the CNT-coated electric wires produced in each example and comparative example.
  • the ratio of the resistance values of the conductors is less than 0.96 in the CNT-coated electric wire in which the carbon nanotube stranded wire as the conductor is coated with the heat-shrinkable tube as the compression coating layer.
  • the volume resistivity ratio ( ⁇ 1 / ⁇ 2) was 0.7 or less, and the obtained CNT-coated electric wire showed excellent conductivity.
  • the CNT stranded wire is directly coated with the heat-shrinkable tube, the CNT strands are firmly fixed to each other by the compression coating layer without using other fixing members.
  • Examples 1 to 4 it is possible to improve the adhesion between the CNT strands while maintaining the weight of the conductor, and to obtain a CNT-coated electric wire having improved conductivity while taking advantage of the light weight of the CNT.
  • the conductivity can be improved even with a small number of twists, and further, when the diameter of the CNT wire 11 is smaller and the number of wires is large, the improvement in conductivity is remarkably exhibited. rice field.
  • Comparative Example 1 in which the ratio of the resistance values of the conductors (R1 / R2) is 0.98, the ratio of the volume resistivity is 0.78, which is inferior in conductivity as compared with Examples 1 to 4. rice field.
  • Comparative Example 1 it is presumed that the CNT stranded wire is not covered with the heat-shrinkable tube by a sufficient compressive force, and the adhesion between the wires is not sufficient, so that a gap is formed between the wires. .. Therefore, in Comparative Example 1, a CNT-coated electric wire showing excellent conductivity could not be obtained.
  • Comparative Example 2 in which the ratio of the resistance values of the conductors (R1 / R2) was 0.99, the conductivity was inferior to that of Examples 1 to 4 as in Comparative Example 1. Further, in Comparative Example 2, the ratio of the conductor diameters ( ⁇ 1 / ⁇ 2) is 0.96, and the adhesion between the strands is not sufficient as compared with Comparative Example 1, so that the CNT-coated electric wire showing sufficient conductivity is exhibited. was not obtained.
  • the ratio of the resistance values of the conductors (R1 / R2) is less than 0.96. It is possible to provide a carbon nanotube-coated electric wire having improved conductivity while taking advantage of the light weight of CNT.

Abstract

A carbon nanotube coated wire (1) according to the present invention is provided with a conductor, and a compression coating layer (20) which coats the conductor. The conductor is a carbon nanotube stranded wire (10) in which a plurality of carbon nanotube wires (11) are twisted, and a ratio (R1/R2) of a resistance value R2 (mΩ/m) of the conductor prior to being coated by the compression coding layer (20) to a resistance value R1 (mΩ/m) after being coated by the compression coding layer (20) is less than 0.96.

Description

カーボンナノチューブ被覆電線Carbon nanotube-coated wire
　本発明は、カーボンナノチューブ被覆電線に関し、特に、圧縮性を示す被覆材料でカーボンナノチューブ撚り線を被覆したカーボンナノチューブ被覆電線に関する。 The present invention relates to a carbon nanotube-coated electric wire, and more particularly to a carbon nanotube-coated electric wire in which a carbon nanotube stranded wire is coated with a coating material exhibiting compressibility.
　自動車、産業機器などの様々な分野における電力線又は信号線として、導体と、該導体を被覆する絶縁被覆とからなる被覆電線が用いられている。導体を構成する線材の材料として、通常、電気特性の観点から銅又は銅合金等の金属線が使用されている。 As a power line or signal line in various fields such as automobiles and industrial equipment, a coated electric wire composed of a conductor and an insulating coating covering the conductor is used. As a material for a wire rod constituting a conductor, a metal wire such as copper or a copper alloy is usually used from the viewpoint of electrical characteristics.
　一方、近年の自動車の軽量化、車内スペースの拡大、信号線の増加等に伴い、現行の電線の軽量化が求められている。電線の軽量化の１つに、導体としてカーボンナノチューブを用いる技術が知られている。カーボンナノチューブは、様々な特性を有する素材であり、多くの分野への応用が期待されている。例えば、カーボンナノチューブは、軽量であると共に、導電性、熱伝導性、機械的強度等の諸特性に優れるため、線材の材料として有望視されている。 On the other hand, with the recent reduction in the weight of automobiles, the expansion of the space inside the car, the increase in signal lines, etc., the weight reduction of the current electric wires is required. A technique of using carbon nanotubes as a conductor is known as one of the weight reductions of electric wires. Carbon nanotubes are materials having various properties and are expected to be applied to many fields. For example, carbon nanotubes are promising as materials for wire rods because they are lightweight and have excellent properties such as conductivity, thermal conductivity, and mechanical strength.
　カーボンナノチューブを線材として用いる場合、電線の強度向上のため、通常はカーボンナノチューブ線材の各素線を撚り合わせた撚り線が使用される。しかしながら、カーボンナノチューブは繊維状の素線であるため、カーボンナノチューブの各素線を長いピッチで撚り合わせた場合、各素線同士の密着性が低下し、撚りがほどけやすくなる。この場合、素線間に隙間が生じてしまうことがあり、導電性の低下を招くおそれがある。一方で、撚りがほどけやすくなることを防ぐために、撚り数を大きくすると、カーボンナノチューブ線材に張力が掛かり、断線による品質低下が生じる可能性がある。そのため、少ない撚り数で撚り線化したカーボンナノチューブ線材を固定し、導電性の低下を抑制する必要がある。 When carbon nanotubes are used as a wire rod, a stranded wire obtained by twisting each strand of the carbon nanotube wire rod is usually used in order to improve the strength of the electric wire. However, since the carbon nanotubes are fibrous strands, when the strands of the carbon nanotubes are twisted at a long pitch, the adhesion between the strands is lowered and the strands are easily untwisted. In this case, a gap may be formed between the wires, which may lead to a decrease in conductivity. On the other hand, if the number of twists is increased in order to prevent the untwisting from becoming easy, tension is applied to the carbon nanotube wire rod, which may cause quality deterioration due to disconnection. Therefore, it is necessary to fix the stranded carbon nanotube wire rod with a small number of twists and suppress the decrease in conductivity.
　特許文献１には、カーボンナノチューブのみで形成された複数のカーボンナノチューブ繊維と、パイプとを備えるカーボンナノチューブ素線において、複数のカーボンナノチューブ繊維を、長手方向の全域にわたってパイプにより外側から固く把持された状態でパイプ内に収納させることが開示されている。特許文献１では、パイプによりカーボンナノチューブ繊維を保持することができるものの、導体としてのカーボンナノチューブ素線の外周を更に筒状の金属製パイプで被覆した場合、追加したパイプの重量分電線の重さが増加する。そのため、カーボンナノチューブの軽量性を発揮できず、電線の軽量化を図ることができない問題がある。また、樹脂製パイプでカーボンナノチューブ素線を被覆した場合、このようなパイプの使用による導電性の影響については言及されていない。 In Patent Document 1, in a carbon nanotube wire provided with a plurality of carbon nanotube fibers formed only of carbon nanotubes and a pipe, the plurality of carbon nanotube fibers are firmly gripped from the outside by a pipe over the entire length direction. It is disclosed that it is stored in a pipe in a state. In Patent Document 1, although the carbon nanotube fiber can be held by the pipe, when the outer periphery of the carbon nanotube wire as a conductor is further covered with a tubular metal pipe, the weight of the electric wire is equal to the weight of the added pipe. Will increase. Therefore, there is a problem that the weight of the carbon nanotube cannot be exhibited and the weight of the electric wire cannot be reduced. Further, when the carbon nanotube wire is coated with a resin pipe, the influence of conductivity due to the use of such a pipe is not mentioned.
特開２０１９－１６０７０９号公報JP-A-2019-160709
　本発明は、カーボンナノチューブの軽量性を活かしつつ、導電性が向上したカーボンナノチューブ被覆電線を提供することを目的とする。 An object of the present invention is to provide a carbon nanotube-coated electric wire having improved conductivity while taking advantage of the light weight of carbon nanotubes.
　本実施形態に係るカーボンナノチューブ被覆電線は、導体と、前記導体を被覆する圧縮被覆層とを備え、前記導体が、複数のカーボンナノチューブ素線が撚り合わされたカーボンナノチューブ撚り線であり、前記圧縮被覆層が被覆される前の導体の抵抗値Ｒ２（ｍΩ／ｍ）に対する前記圧縮被覆層が被覆された後の導体の抵抗値Ｒ１（ｍΩ／ｍ）の比（Ｒ１／Ｒ２）が、０．９６未満である。 The carbon nanotube-coated electric wire according to the present embodiment includes a conductor and a compression coating layer covering the conductor, and the conductor is a carbon nanotube stranded wire in which a plurality of carbon nanotube strands are twisted, and the compression coating is provided. The ratio (R1 / R2) of the resistance value R1 (mΩ / m) of the conductor after the compression coating layer is coated to the resistance value R2 (mΩ / m) of the conductor before the layer is coated is 0.96. Is less than.
　本発明の一実施態様において、前記圧縮被覆層が被覆される前の導体径φ２（ｍｍ）に対する前記圧縮被覆層が被覆された後の導体径φ１（ｍｍ）の比（φ１／φ２）が、０．９５未満である。 In one embodiment of the present invention, the ratio (φ1 / φ2) of the conductor diameter φ1 (mm) after the compression coating layer is coated to the conductor diameter φ2 (mm) before the compression coating layer is coated is determined. It is less than 0.95.
　本発明の一実施態様において、前記カーボンナノチューブ素線の素線径が１５０μｍ以下であり、且つ、前記カーボンナノチューブ素線の本数が２０本以上である。 In one embodiment of the present invention, the diameter of the carbon nanotube strands is 150 μm or less, and the number of carbon nanotube strands is 20 or more.
　本発明の一実施態様において、前記カーボンナノチューブ素線の素線径が８０μｍ以下であり、且つ、前記カーボンナノチューブ素線の本数が５０本以上である。 In one embodiment of the present invention, the diameter of the carbon nanotube strands is 80 μm or less, and the number of carbon nanotube strands is 50 or more.
　本発明の一実施態様において、前記カーボンナノチューブ撚り線の撚り数が５０Ｔ／ｍ以上４００Ｔ／ｍ以下である。 In one embodiment of the present invention, the number of twists of the carbon nanotube stranded wire is 50 T / m or more and 400 T / m or less.
　本発明の他の実施態様に係るカーボンナノチューブ被覆電線は、導体と、前記導体を被覆する圧縮被覆層とを備え、前記導体が、複数のカーボンナノチューブ素線が撚り合わされたカーボンナノチューブ撚り線であり、前記カーボンナノチューブ素線の素線径が１５０μｍ以下であり、且つ、前記カーボンナノチューブ素線の本数が２０本以上であり、前記カーボンナノチューブ撚り線の撚り数が８０Ｔ／ｍ以上３００Ｔ／ｍ以下であり、且つ、前記圧縮被覆層が被覆された後の導体径φ１が１．３ｍｍ以下である。 The carbon nanotube-coated electric wire according to another embodiment of the present invention is a carbon nanotube stranded wire comprising a conductor and a compression coating layer covering the conductor, and the conductor is a stranded carbon nanotube wire in which a plurality of carbon nanotube strands are twisted. When the wire diameter of the carbon nanotube wire is 150 μm or less, the number of carbon nanotube wires is 20 or more, and the number of twists of the carbon nanotube stranded wire is 80 T / m or more and 300 T / m or less. The conductor diameter φ1 after the compression coating layer is coated is 1.3 mm or less.
　本発明の一実施態様において、前記カーボンナノチューブ素線の素線径が５０μｍ以下であり、且つ、前記カーボンナノチューブ素線の本数が１００本以上である。 In one embodiment of the present invention, the diameter of the carbon nanotube strands is 50 μm or less, and the number of carbon nanotube strands is 100 or more.
　本発明の一実施態様において、前記圧縮被覆層が熱収縮チューブである。 In one embodiment of the present invention, the compression coating layer is a heat shrinkable tube.
　本発明の一実施態様において、前記カーボンナノチューブ撚り線が、５００ＭＰａ以上の曲げ弾性率を有する前記圧縮被覆層により保持されている。 In one embodiment of the present invention, the carbon nanotube stranded wire is held by the compression coating layer having a flexural modulus of 500 MPa or more.
　本発明の一実施態様において、前記圧縮被覆層の外周に更に絶縁樹脂層が設けられている。 In one embodiment of the present invention, an insulating resin layer is further provided on the outer periphery of the compression coating layer.
　本発明の一実施態様において、前記カーボンナノチューブ被覆電線は自動車用ワイヤハーネスとして使用される。 In one embodiment of the present invention, the carbon nanotube-coated electric wire is used as a wire harness for an automobile.
　本発明によれば、カーボンナノチューブの軽量性を活かしつつ、導電性が向上したカーボンナノチューブ被覆電線を得ることができる。 According to the present invention, it is possible to obtain a carbon nanotube-coated electric wire having improved conductivity while taking advantage of the light weight of carbon nanotubes.
本発明の実施形態に係るカーボンナノチューブ被覆電線の一例を示す概略断面図である。It is a schematic cross-sectional view which shows an example of the carbon nanotube-coated electric wire which concerns on embodiment of this invention. 本発明の実施形態に係るカーボンナノチューブ被覆電線において、カーボンナノチューブ撚り線を圧縮被覆層で被覆する前の導体の一例を示す概略断面図である。It is a schematic cross-sectional view which shows an example of the conductor before coating the carbon nanotube stranded wire with a compression coating layer in the carbon nanotube coated electric wire which concerns on embodiment of this invention.
　以下に、本発明の実施形態に係るカーボンナノチューブ被覆電線について、図面を用いながら説明する。 The carbon nanotube-coated electric wire according to the embodiment of the present invention will be described below with reference to the drawings.
［カーボンナノチューブ被覆電線］
　図１に示すように、本発明の実施形態に係るカーボンナノチューブ被覆電線（以下、「ＣＮＴ被覆電線」ということがある。）１は、導体としてのカーボンナノチューブ撚り線（以下、「ＣＮＴ撚り線」ということがある。）１０と、ＣＮＴ撚り線１０を被覆する圧縮被覆層２０とを備え、ＣＮＴ撚り線１０の外周面に圧縮被覆層２０が被覆されている。すなわち、ＣＮＴ撚り線１０の長手方向に沿って圧縮被覆層２０が被覆されている。ＣＮＴ被覆電線１では、ＣＮＴ撚り線１０の外周面全体が、圧縮被覆層２０によって被覆されているため、圧縮被覆層２０はＣＮＴ撚り線１０の外周面と密着している。 [Carbon nanotube-coated wire]
As shown in FIG. 1, the carbon nanotube-coated electric wire (hereinafter, may be referred to as “CNT-coated electric wire”) 1 according to the embodiment of the present invention is a carbon nanotube stranded wire as a conductor (hereinafter, “CNT stranded wire”. The compression coating layer 20 for coating the CNT stranded wire 10 is provided, and the outer peripheral surface of the CNT stranded wire 10 is coated with the compression coating layer 20. That is, the compression coating layer 20 is coated along the longitudinal direction of the CNT stranded wire 10. In the CNT-coated electric wire 1, since the entire outer peripheral surface of the CNT stranded wire 10 is covered with the compression coating layer 20, the compression coating layer 20 is in close contact with the outer peripheral surface of the CNT stranded wire 10.
［導体］
　ＣＮＴ撚り線１０は、カーボンナノチューブ集合体（以下、「ＣＮＴ集合体」ということがある。）から形成されており、ＣＮＴ集合体がカーボンナノチューブ素線（以下、「ＣＮＴ素線」ということがある。）１１として使用される。ＣＮＴ撚り線１０は、複数のＣＮＴ素線１１が撚り合わされて形成されている。ＣＮＴの導体を撚り線の形態とすることで、導体を太線化することができ、強度が向上する。ＣＮＴ撚り線１０の導体径（円相当直径）は、特に限定されないが、例えば、０．１ｍｍ以上１０ｍｍ以下であることが好ましい。また、ＣＮＴ撚り線１０の断面積は、０．００５ｍｍ２以上５０ｍｍ２以下であることが好ましい。尚、円相当直径は、ＣＮＴ撚り線１０の径方向の断面観察から断面積を算出し、これと同じ面積となる円の直径を算出することにより求められる。 [conductor]
The CNT stranded wire 10 is formed of a carbon nanotube aggregate (hereinafter, may be referred to as “CNT aggregate”), and the CNT aggregate may be referred to as a carbon nanotube wire (hereinafter, “CNT wire”). .) Used as 11. The CNT stranded wire 10 is formed by twisting a plurality of CNT strands 11. By forming the CNT conductor in the form of a stranded wire, the conductor can be made thicker and the strength is improved. The conductor diameter (diameter equivalent to a circle) of the CNT stranded wire 10 is not particularly limited, but is preferably 0.1 mm or more and 10 mm or less, for example. Further, the cross-sectional area of the CNT stranded wire 10 is preferably 0.005 mm 2 or more and 50 mm 2 or less. The circle-equivalent diameter is obtained by calculating the cross-sectional area from the observation of the cross section of the CNT stranded wire 10 in the radial direction and calculating the diameter of the circle having the same area.
　ＣＮＴ撚り線１０には、異種元素がドープされていてもよい。この場合、ＣＮＴ撚り線１０は、ＣＮＴ素線１１に異種元素がドープされたカーボンナノチューブ複合体の複数が撚り合わされて形成されてもよい。異種元素のドーピングにより、ＣＮＴ撚り線１０の導電性を向上させることができる。異種元素として、例えば、硝酸、硫酸、ヨウ素、臭素、カリウム、ナトリウム、ホウ素及び窒素からなる群から選択される１つ以上の元素又は分子が挙げられる。 The CNT stranded wire 10 may be doped with a different element. In this case, the CNT stranded wire 10 may be formed by twisting a plurality of carbon nanotube composites in which a dissimilar element is doped into the CNT strand 11. By doping with different elements, the conductivity of the CNT stranded wire 10 can be improved. Dissimilar elements include, for example, one or more elements or molecules selected from the group consisting of nitric acid, sulfuric acid, iodine, bromine, potassium, sodium, boron and nitrogen.
　ＣＮＴ撚り線１０は、複数のＣＮＴ素線１１を束ねて一端を固定した状態で、もう一端を所定の回数ひねることで、撚り線として形成することができる。ＣＮＴ撚り線１０の撚り数（撚り度）は、複数のＣＮＴ素線１１を撚り合わせた際の単位長さ当たりの巻き数で表される。すなわち、撚り数は、ひねった回数（Ｔ）を線の長さ（ｍ）で割った値（単位：Ｔ／ｍ）で表すことができる。ＣＮＴ撚り線１０の撚り数（Ｔ／ｍ）は、ＣＮＴ撚り線１０に一定の強度を付与させるため、０Ｔ／ｍを超え１０００Ｔ／ｍ以下であることが好ましく、５０Ｔ／ｍ以上４００Ｔ／ｍ以下であることがより好ましい。特に、ＣＮＴ撚り線１０の撚り数が８０Ｔ／ｍ以上３００Ｔ／ｍ以下であることにより、強度が向上し、撚り加工プロセスを簡略化することができる。 The CNT stranded wire 10 can be formed as a stranded wire by bundling a plurality of CNT strands 11 and fixing one end thereof, and twisting the other end a predetermined number of times. The number of twists (twist degree) of the CNT stranded wire 10 is represented by the number of turns per unit length when a plurality of CNT strands 11 are twisted together. That is, the number of twists can be expressed by a value (unit: T / m) obtained by dividing the number of twists (T) by the length (m) of the wire. The number of twists (T / m) of the CNT stranded wire 10 is preferably more than 0 T / m and 1000 T / m or less, preferably 50 T / m or more and 400 T / m or less, in order to impart a certain strength to the CNT stranded wire 10. Is more preferable. In particular, when the number of twists of the CNT stranded wire 10 is 80 T / m or more and 300 T / m or less, the strength can be improved and the twisting process can be simplified.
　ＣＮＴ撚り線１０では、ＣＮＴ素線１１は隣接する他のＣＮＴ素線１１と直接接触している。また、ＣＮＴ素線１１は長手方向の導電性に優れている。ＣＮＴ素線１１が隣接する他のＣＮＴ素線１１と直接接触しているため、ＣＮＴ撚り線１０は、全体で優れた導電性を発揮する。 In the CNT stranded wire 10, the CNT wire 11 is in direct contact with another adjacent CNT wire 11. Further, the CNT wire 11 is excellent in conductivity in the longitudinal direction. Since the CNT wire 11 is in direct contact with another adjacent CNT wire 11, the CNT stranded wire 10 exhibits excellent conductivity as a whole.
　また、撚り数が多いと、撚り加工によりＣＮＴ素線１１に張力が掛かり、ＣＮＴ素線１１の断線による品質低下が生じる可能性がある。そのため、上記のような８０Ｔ／ｍ以上３００Ｔ／ｍ以下の比較的少ない撚り数とすることで、このようなリスクを低減することができる。さらに、後述するように、熱圧縮性樹脂による圧縮被覆層２０を配することで、ＣＮＴ素線１１同士の接触を保持しながら優れた導電性を発揮することができる。 Further, if the number of twists is large, tension is applied to the CNT wire 11 due to the twisting process, and there is a possibility that the quality of the CNT wire 11 is deteriorated due to the disconnection of the wire 11. Therefore, such a risk can be reduced by setting a relatively small number of twists of 80 T / m or more and 300 T / m or less as described above. Further, as will be described later, by arranging the compression coating layer 20 made of a heat-compressible resin, excellent conductivity can be exhibited while maintaining contact between the CNT strands 11.
　ＣＮＴ被覆電線１に用いられるＣＮＴ素線１１は、１層以上の層構造を有する複数のカーボンナノチューブ（以下、「ＣＮＴ」ということがある。）で構成される。ここで、ＣＮＴ撚り線１０はＣＮＴの割合が７０質量％以上のＣＮＴ線材を意味する。なお、ＣＮＴ撚り線におけるＣＮＴ割合の算定においては、メッキとドーパントは除かれる。ＣＮＴ素線１１の長手方向が、ＣＮＴ撚り線１０の長手方向を形成しているため、ＣＮＴ素線１１は線状となっている。 The CNT wire 11 used for the CNT-coated electric wire 1 is composed of a plurality of carbon nanotubes having a layer structure of one or more layers (hereinafter, may be referred to as “CNT”). Here, the CNT stranded wire 10 means a CNT wire having a CNT ratio of 70% by mass or more. In addition, plating and dopants are excluded in the calculation of the CNT ratio in the CNT stranded wire. Since the longitudinal direction of the CNT strand 11 forms the longitudinal direction of the CNT stranded wire 10, the CNT strand 11 is linear.
　ＣＮＴ素線１１は、１層以上の層構造を有する長尺なＣＮＴの束である。ＣＮＴの長手方向が、ＣＮＴ素線１１の長手方向を形成している。ＣＮＴ素線１１の素線径（円相当直径）は、１０μｍ以上１５０μｍ以下であることが好ましく、素線径の下限は２０μｍ以上であることがより好ましい。また、素線径の上限は８０μｍ以下であることがより好ましく、５０μｍ以下であることがより好ましい。また、ＣＮＴ撚り線１０を構成するＣＮＴ素線１１の本数は、２０本以上１０００本以下であることが好ましく、ＣＮＴ素線１１の本数の下限は５０本以上であることがより好ましく、１００本以上であることがさらに好ましい。また、ＣＮＴ素線１１の本数の上限は８００本以下であることがより好ましい。特に、ＣＮＴ素線１１の素線径が８０μｍ以下であり、且つＣＮＴ素線１１の本数が５０本以上であることにより、圧縮被覆による各ＣＮＴ素線１１の接触面積が増大する効果が向上するため、導電性がより向上したＣＮＴ被覆電線１を得ることができる。さらに、ＣＮＴ素線１１の素線径が５０μｍ以下であり、且つＣＮＴ素線１１の本数が１００本以上であることにより、上記効果が顕著に生じるＣＮＴ被覆電線１を得ることができる。 The CNT wire 11 is a bundle of long CNTs having a layered structure of one or more layers. The longitudinal direction of the CNT forms the longitudinal direction of the CNT wire 11. The wire diameter (diameter equivalent to a circle) of the CNT wire 11 is preferably 10 μm or more and 150 μm or less, and the lower limit of the wire diameter is more preferably 20 μm or more. Further, the upper limit of the wire diameter is more preferably 80 μm or less, and more preferably 50 μm or less. The number of CNT strands 11 constituting the CNT stranded wire 10 is preferably 20 or more and 1000 or less, and the lower limit of the number of CNT strands 11 is more preferably 50 or more, more preferably 100. The above is more preferable. Further, it is more preferable that the upper limit of the number of CNT strands 11 is 800 or less. In particular, when the wire diameter of the CNT wire 11 is 80 μm or less and the number of the CNT wire 11 is 50 or more, the effect of increasing the contact area of each CNT wire 11 by the compression coating is improved. Therefore, it is possible to obtain the CNT-coated electric wire 1 having further improved conductivity. Further, when the wire diameter of the CNT wire 11 is 50 μm or less and the number of the CNT wire 11 is 100 or more, the CNT-coated electric wire 1 in which the above effect is remarkably obtained can be obtained.
　ＣＮＴ素線１１を構成するＣＮＴは、単層構造又は複層構造を有する筒状体であり、それぞれ、ＳＷＮＴ（single-walled nanotube）、ＭＷＮＴ（multi-walled nanotube）と呼ばれる。ＣＮＴ素線１１には、単層構造の層構造を有するＣＮＴ、２層構造を有するＣＮＴ又は３層構造以上の層構造を有するＣＮＴのいずれかから形成されていてもよく、これらの層構造を有するＣＮＴを複数用いて形成されていてもよい。 The CNTs constituting the CNT wire 11 are tubular bodies having a single-walled structure or a multi-walled structure, and are called SWNTs (single-walled nanotubes) and MWNTs (multi-walled nanotubes), respectively. The CNT wire 11 may be formed of either a CNT having a single-walled layer structure, a CNT having a two-layer structure, or a CNT having a three-layer structure or more, and these layer structures may be formed. It may be formed by using a plurality of CNTs having.
　ＣＮＴ素線１１を構成するＣＮＴにおいて、２層構造を有するＣＮＴでは、六角形格子の網目構造を有する２つの筒状体が略同軸で配された３次元網目構造体となっており、ＤＷＮＴ（Double-walled nanotube）と呼ばれる。構成単位である六角形格子は、その頂点に炭素原子が配された六員環であり、他の六員環と隣接してこれらが連続的に結合している。 Among the CNTs constituting the CNT wire 11, the CNT having a two-layer structure is a three-dimensional network structure in which two cylindrical bodies having a network structure of a hexagonal lattice are arranged substantially coaxially. It is called Double-walled nanotube). The hexagonal lattice, which is a constituent unit, is a six-membered ring in which carbon atoms are arranged at its vertices, and these are continuously bonded adjacent to other six-membered rings.
　ＣＮＴ素線１１を構成するＣＮＴの性質は、上記筒状体のカイラリティに依存する。カイラリティは、アームチェア型、ジグザグ型、及びカイラル型に大別され、アームチェア型は金属性、ジグザグ型は半導体性及び半金属性、カイラル型は半導体性及び半金属性の挙動を示す。よって、ＣＮＴの導電性は、筒状体がいずれのカイラリティを有するかによって大きく異なる。 The properties of the CNTs constituting the CNT wire 11 depend on the chirality of the tubular body. Chirality is roughly classified into an armchair type, a zigzag type, and a chiral type. The armchair type exhibits metallic behavior, the zigzag type exhibits semiconductor and semimetal properties, and the chiral type exhibits semiconductor and semimetal properties. Therefore, the conductivity of CNTs differs greatly depending on which chirality the tubular body has.
［圧縮被覆層］
　次に、ＣＮＴ被覆電線１に用いるＣＮＴ撚り線１０の外周面を被覆する圧縮被覆層２０について説明する。 [Compression coating layer]
Next, the compression coating layer 20 that covers the outer peripheral surface of the CNT stranded wire 10 used for the CNT-coated electric wire 1 will be described.
　本実施形態に係るＣＮＴ被覆電線１において、圧縮被覆層２０の材料として熱収縮可能な材料が使用される。このような圧縮被覆層２０は、ＣＮＴ撚り線１０を内部に挿入可能な筒状体であることが好ましく、市場で入手可能な熱収縮チューブであることがより好ましい。具体例として、圧縮被覆層２０が熱収縮チューブである場合、熱収縮チューブの内部にＣＮＴ撚り線１０を挿入し、加熱することにより熱収縮チューブが収縮してＣＮＴ撚り線１０に圧縮力のある被覆が施される。これにより、ＣＮＴ素線１１同士の密着性が向上し、ＣＮＴ素線１１の撚りが固定される。その結果、ＣＮＴ素線１１間の隙間の発生が抑制され、ＣＮＴ被覆電線１の導電性の低下を抑制することができる。 In the CNT-coated electric wire 1 according to the present embodiment, a heat-shrinkable material is used as the material of the compression coating layer 20. Such a compression coating layer 20 is preferably a tubular body into which the CNT stranded wire 10 can be inserted, and more preferably a heat-shrinkable tube available on the market. As a specific example, when the compression coating layer 20 is a heat-shrinkable tube, the heat-shrinkable tube 10 is inserted into the heat-shrinkable tube and heated to shrink the heat-shrinkable tube, and the CNT stranded wire 10 has a compressive force. The coating is applied. As a result, the adhesion between the CNT strands 11 is improved, and the twist of the CNT strands 11 is fixed. As a result, the generation of gaps between the CNT strands 11 can be suppressed, and the decrease in conductivity of the CNT-coated electric wire 1 can be suppressed.
　圧縮被覆層２０の材料として、例えば、ポリテトラフルオロエチレン、ポリオレフィン、ポリ塩化ビニル、エチレンプロピレンゴム、シリコーンゴム等が挙げられ、加熱する前の材料が使用される。これらの材料は、単独で使用してもよく、２種以上を適宜混合して使用してもよい。 Examples of the material of the compression coating layer 20 include polytetrafluoroethylene, polyolefin, polyvinyl chloride, ethylene propylene rubber, silicone rubber, and the like, and the material before heating is used. These materials may be used alone or in admixture of two or more.
　ＣＮＴ被覆電線１において、圧縮被覆層２０がＣＮＴ撚り線１０を圧縮する力は特に限定されないが、圧縮被覆層２０の材料や、その組み合わせ、加熱温度と加熱時間等により調整することができる。その際、ＣＮＴ撚り線１０が５００ＭＰａ以上の（圧縮後の）曲げ弾性率を有する圧縮被覆層２０で保持されるよう調整することで、ＣＮＴ撚り線１０を適切に圧縮することができる。曲げ弾性率が５００ＭＰａ以上であることにより、ＣＮＴ撚り線１０が圧縮被覆層２０を介してより確実に保持され、圧縮被覆層２０の圧縮を長期間維持することができる。また、曲げ弾性率の上限は４０００ＭＰａ以下であることが好ましく、１０００ＭＰａ以下であることがより好ましく、６００ＭＰａ以下であることがさらに好ましい。曲げ弾性率の上限は４０００ＭＰａ以下であることにより、ＣＮＴ被覆電線１が曲げにくくなることを防止し、後工程における加工を容易に行うことができる。樹脂の曲げ弾性率の測定は、ＪＩＳ　Ｋ７１７１（２０１６）に準拠した方法により測定できる。また、５００ＭＰａ以上の曲げ弾性率は、特に、ＣＮＴ素線１１の素線径が１５０μｍ以下であり、ＣＮＴ素線１１の本数が２０本以上であり、且つ、ＣＮＴ撚り線１０の撚り数が８０Ｔ／ｍ以上３００Ｔ／ｍ以下である場合において、ＣＮＴ素線１１の接触面積が増大する効果を発揮できるため好適であり、さらに、ＣＮＴ素線１１の素線径がより細く、本数が多い場合にその効果を顕著に発揮することができる。 In the CNT-coated electric wire 1, the force with which the compression coating layer 20 compresses the CNT stranded wire 10 is not particularly limited, but it can be adjusted depending on the material of the compression coating layer 20, the combination thereof, the heating temperature, the heating time, and the like. At that time, the CNT stranded wire 10 can be appropriately compressed by adjusting so that the CNT stranded wire 10 is held by the compression coating layer 20 having a flexural modulus (after compression) of 500 MPa or more. When the flexural modulus is 500 MPa or more, the CNT stranded wire 10 is more reliably held via the compression coating layer 20, and the compression of the compression coating layer 20 can be maintained for a long period of time. The upper limit of the flexural modulus is preferably 4000 MPa or less, more preferably 1000 MPa or less, and even more preferably 600 MPa or less. Since the upper limit of the flexural modulus is 4000 MPa or less, it is possible to prevent the CNT-coated electric wire 1 from becoming difficult to bend, and it is possible to easily perform processing in a subsequent process. The flexural modulus of the resin can be measured by a method based on JIS K7171 (2016). Further, the flexural modulus of 500 MPa or more is such that the diameter of the CNT wire 11 is 150 μm or less, the number of the CNT wire 11 is 20 or more, and the number of twists of the CNT stranded wire 10 is 80 T. When it is / m or more and 300 T / m or less, it is suitable because it can exert the effect of increasing the contact area of the CNT wire 11, and further, when the diameter of the CNT wire 11 is smaller and the number of wires is larger. The effect can be remarkably exhibited.
　圧縮被覆層２０の外周には更に絶縁樹脂層が設けられていてもよい。絶縁樹脂層の材料は、一般的に使用される絶縁樹脂であれば特に限定されるものではない。また、絶縁樹脂層は押出被覆による一般的な加工方法で形成され、加熱した絶縁樹脂を被覆材料して用いられる。すなわち、絶縁樹脂層には加熱した材料が使用されるため、樹脂材料によらず、絶縁樹脂層は熱収縮しない。このような絶縁樹脂層の材料として、例えば、ポリ塩化ビニル、ポリビニルアルコール、ポリスチレン、ポリエチレン、ポリプロピレン、ポリアセタール、ポリメチルメタクリレート、酢酸セルロース、ポリカーボネイト、ポリエチレンテレフタレート、ポリアミド、ポリアミドイミド、ポリクロロトリフルオロエチレン、ポリテトラフルオロエチレン、ポリフッ化ビニリデン、スチレン・アクリロニトリル共重合体、スチレン・ブタジエン・アクリロニトリル共重合体、エナメル等を挙げることができる。これらは、単独で使用してもよく、２種以上を適宜混合して使用してもよい。圧縮被覆層２０上に更に絶縁樹脂層を被覆することで、圧縮被覆層２０における絶縁性、形状保持性、耐候性を強化することができる。また、絶縁樹脂層は圧縮被覆層２０との密着性の相性が良いため、ＣＮＴ撚り線１０上に絶縁樹脂層を被覆するよりも接着強度がより高くなり得る。 An insulating resin layer may be further provided on the outer periphery of the compression coating layer 20. The material of the insulating resin layer is not particularly limited as long as it is a generally used insulating resin. Further, the insulating resin layer is formed by a general processing method by extrusion coating, and a heated insulating resin is used as a coating material. That is, since a heated material is used for the insulating resin layer, the insulating resin layer does not heat shrink regardless of the resin material. Examples of the material of such an insulating resin layer include polyvinylidene chloride, polyvinyl alcohol, polystyrene, polyethylene, polypropylene, polyacetal, polymethylmethacrylate, cellulose acetate, polycarbonate, polyethylene terephthalate, polyamide, polyamideimide, and polychlorotrifluoroethylene. Examples thereof include polytetrafluoroethylene, polyvinylidene fluoride, styrene / acrylonitrile copolymer, styrene / butadiene / acrylonitrile copolymer, and enamel. These may be used alone, or two or more kinds may be appropriately mixed and used. By further coating the compression coating layer 20 with an insulating resin layer, the insulation, shape retention, and weather resistance of the compression coating layer 20 can be enhanced. Further, since the insulating resin layer has good adhesion to the compression coating layer 20, the adhesive strength can be higher than that of coating the insulating resin layer on the CNT stranded wire 10.
　圧縮被覆層２０と絶縁樹脂層との総厚は、特に限定されるものではないが、０．００２ｍｍ以上２ｍｍ以下であることが好ましく、０．００５ｍｍ以上１ｍｍ以下であることがより好ましい。また、圧縮被覆層２０の厚さは、特に限定されるものではないが、０．００１ｍｍ以上１．５ｍｍ以下であることが好ましく、０．００２５ｍｍ以上０．５ｍｍ以下であることがより好ましい。また、圧縮被覆層２０が熱収縮チューブである場合、熱収縮チューブの径は、ＣＮＴ撚り線１０の導体径に対して１．０５～１．５倍であることが好ましい。 The total thickness of the compression coating layer 20 and the insulating resin layer is not particularly limited, but is preferably 0.002 mm or more and 2 mm or less, and more preferably 0.005 mm or more and 1 mm or less. The thickness of the compression coating layer 20 is not particularly limited, but is preferably 0.001 mm or more and 1.5 mm or less, and more preferably 0.0025 mm or more and 0.5 mm or less. When the compression coating layer 20 is a heat-shrinkable tube, the diameter of the heat-shrinkable tube is preferably 1.05 to 1.5 times the conductor diameter of the CNT stranded wire 10.
＜導体の抵抗値の比＞
　本実施形態に係るＣＮＴ被覆電線１において、圧縮被覆層２０が被覆される前の導体の抵抗値Ｒ２（ｍΩ／ｍ）に対する圧縮被覆層２０が被覆された後の導体の抵抗値Ｒ１（ｍΩ／ｍ）の比Ｒ１／Ｒ２は、０．９６未満であり、０．９以下であることが好ましく、０．７以下であることがより好ましい。比（Ｒ１／Ｒ２）が０．９６未満になるようにＣＮＴ撚り線１０にかかる圧縮力を制御することにより、ＣＮＴ撚り線１０を構成する各ＣＮＴ素線１１同士の密着性が高まり、導電性の低下が抑制される。また、圧縮被覆層２０が被覆された導体の体積抵抗率が、圧縮被覆層２０が被覆される前の導体に比べて低下する。そのため、導電性が向上したＣＮＴ被覆電線１を得ることができる。さらに、ＣＮＴ撚り線１０を、パイプ等の他の部材を介在さずとも圧縮被覆層２０により固定することができる。また、長手方向の抵抗値のばらつきを小さくするため、比（Ｒ１／Ｒ２）の下限は０．３以上であることが好ましい。 <Ratio of conductor resistance>
In the CNT-coated electric wire 1 according to the present embodiment, the resistance value R1 (mΩ / m) of the conductor after the compression coating layer 20 is coated with respect to the resistance value R2 (mΩ / m) of the conductor before the compression coating layer 20 is coated. The ratio R1 / R2 of m) is less than 0.96, preferably 0.9 or less, and more preferably 0.7 or less. By controlling the compressive force applied to the CNT stranded wire 10 so that the ratio (R1 / R2) is less than 0.96, the adhesion between the CNT strands 11 constituting the CNT stranded wire 10 is enhanced, and the conductivity is increased. The decrease is suppressed. Further, the volume resistivity of the conductor coated with the compression coating layer 20 is lower than that of the conductor before the compression coating layer 20 is coated. Therefore, the CNT-coated electric wire 1 having improved conductivity can be obtained. Further, the CNT stranded wire 10 can be fixed by the compression coating layer 20 without interposing another member such as a pipe. Further, in order to reduce the variation in the resistance value in the longitudinal direction, the lower limit of the ratio (R1 / R2) is preferably 0.3 or more.
　導体の抵抗値Ｒ１の範囲は、例えば、０．９６ｍΩ／ｍ以上９６０ｍΩ／ｍ以下であることが好ましく、導体の抵抗値Ｒ２の範囲は、例えば、１ｍΩ／ｍを超え１０００ｍΩ／ｍ以下であることが好ましい。尚、導体の抵抗値Ｒ１、Ｒ２は、例えば四端子法により測定される。 The range of the resistance value R1 of the conductor is preferably 0.96 mΩ / m or more and 960 mΩ / m or less, and the range of the resistance value R2 of the conductor is, for example, more than 1 mΩ / m and 1000 mΩ / m or less. Is preferable. The resistance values R1 and R2 of the conductor are measured by, for example, the four-terminal method.
＜導体径の比＞
　本実施形態に係るＣＮＴ被覆電線１において、圧縮被覆層２０が被覆される前の導体径φ２に対する圧縮被覆層２０が被覆された後の導体径φ１の比（φ１／φ２）が、０．９５未満であることが好ましく、０．９以下であることがより好ましく、０．８５以下であることがさらに好ましい。具体的には、図１に示されるような、ＣＮＴ撚り線１０が圧縮被覆層２０で被覆された後の導体径φ１が、図２に示されるような、ＣＮＴ撚り線１０が圧縮被覆層２０で被覆される前の導体径φ２よりも所定の比率で小さくなるように比（φ１／φ２）が制御される。これにより、ＣＮＴ撚り線１０がより確実に圧縮被覆層２０で固定されるため、ＣＮＴ素線１１同士の密着性が向上し、ＣＮＴ素線１１間の隙間の発生に起因する導電性の低下を抑制することができる。また、ＣＮＴ撚り線１０に過剰な圧縮力がかかり、ＣＮＴ素線の断線を防止するため、比（φ１／φ２）の下限は０．７以上であることが好ましい。 <Ratio of conductor diameter>
In the CNT-coated electric wire 1 according to the present embodiment, the ratio (φ1 / φ2) of the conductor diameter φ1 after the compression coating layer 20 is coated to the conductor diameter φ2 before the compression coating layer 20 is coated is 0.95. It is preferably less than, more preferably 0.9 or less, and even more preferably 0.85 or less. Specifically, the conductor diameter φ1 after the CNT stranded wire 10 is coated with the compression coating layer 20 as shown in FIG. 1 is the conductor diameter φ1 as shown in FIG. 2, and the CNT stranded wire 10 is the compression coating layer 20 as shown in FIG. The ratio (φ1 / φ2) is controlled so as to be smaller than the conductor diameter φ2 before being coated with. As a result, the CNT stranded wire 10 is more reliably fixed by the compression coating layer 20, so that the adhesion between the CNT strands 11 is improved, and the conductivity is reduced due to the generation of gaps between the CNT strands 11. It can be suppressed. Further, the lower limit of the ratio (φ1 / φ2) is preferably 0.7 or more in order to prevent the CNT strand wire from being broken due to an excessive compressive force applied to the CNT stranded wire 10.
　導体径φ１の範囲は、例えば、０．０９５ｍｍ以上９．５ｍｍ以下であることが好ましく、導体径φ１の下限は、０．３ｍｍ以上であることが好ましく、０．５ｍｍ以上であることがより好ましい。また、導体径φ１の上限は、５．０ｍｍ以下であることが好ましく、１．３ｍｍ以下であることがより好ましい。一方、導体径φ２の範囲は、例えば、０．１ｍｍ以上１０ｍｍ以下であることが好ましく、導体径φ２の下限は、０．３ｍｍ以上であることが好ましく、０．５ｍｍ以上であることがより好ましい。また、導体径φ２の上限は、５．０ｍｍ以下であることが好ましく、１．５ｍｍ以下であることがより好ましい。特に、１．３ｍｍ以下の導体径φ１の上限は、ＣＮＴ素線１１の素線径が１５０μｍ以下であり、ＣＮＴ素線１１の本数が２０本以上であり、且つ、ＣＮＴ撚り線１０の撚り数が８０Ｔ／ｍ以上３００Ｔ／ｍ以下である場合において、少ない撚り数でも導電性を向上させることができるため好適であり、さらに、ＣＮＴ素線１１の素線径がより細く、本数が多い場合にその効果を顕著に発揮することができる。尚、導体径φ１、φ２は、例えば断面のマイクロスコープ観察により測定された断面積から円相当直径を算出することで得られる。 The range of the conductor diameter φ1 is preferably 0.095 mm or more and 9.5 mm or less, and the lower limit of the conductor diameter φ1 is preferably 0.3 mm or more, more preferably 0.5 mm or more. .. The upper limit of the conductor diameter φ1 is preferably 5.0 mm or less, and more preferably 1.3 mm or less. On the other hand, the range of the conductor diameter φ2 is preferably 0.1 mm or more and 10 mm or less, and the lower limit of the conductor diameter φ2 is preferably 0.3 mm or more, more preferably 0.5 mm or more. .. The upper limit of the conductor diameter φ2 is preferably 5.0 mm or less, and more preferably 1.5 mm or less. In particular, the upper limit of the conductor diameter φ1 of 1.3 mm or less is that the wire diameter of the CNT wire 11 is 150 μm or less, the number of the CNT wire 11 is 20 or more, and the number of twists of the CNT stranded wire 10 is 20 or more. Is suitable when the wire diameter is 80 T / m or more and 300 T / m or less, because the conductivity can be improved even with a small number of twists, and further, when the wire diameter of the CNT wire 11 is smaller and the number of wires is large. The effect can be remarkably exhibited. The conductor diameters φ1 and φ2 can be obtained by calculating the circle-equivalent diameter from the cross-sectional area measured by, for example, observing the cross section with a microscope.
［ＣＮＴ被覆電線の製造方法］
　次に、本発明の実施形態に係るＣＮＴ被覆電線１の製造方法例について説明する。ＣＮＴ被覆電線１は、まず、ＣＮＴを作製し、得られた複数のＣＮＴからＣＮＴ素線１１を作製する。次いで、得られた複数のＣＮＴ素線１１を撚り合わせてＣＮＴ撚り線１０を作製する。その後、ＣＮＴ撚り線１０の外周面に圧縮被覆層２０を被覆することで、ＣＮＴ被覆電線１を製造することができる。 [Manufacturing method of CNT-coated electric wire]
Next, an example of a method for manufacturing the CNT-coated electric wire 1 according to the embodiment of the present invention will be described. The CNT-coated electric wire 1 first prepares CNTs, and then prepares CNT strands 11 from the obtained plurality of CNTs. Next, the obtained plurality of CNT strands 11 are twisted together to produce a CNT stranded wire 10. After that, the CNT-coated electric wire 1 can be manufactured by coating the outer peripheral surface of the CNT stranded wire 10 with the compression coating layer 20.
　ＣＮＴ１１は、例えば、浮遊触媒法（特許第5819888号）、基板法（特許第5590603号）等の方法で作製することができ、浮遊触媒法が好ましい。また、ＣＮＴ素線１１は、例えば、乾式紡糸（特許第5819888号、特許第5990202号、特許第5350635号）、湿式紡糸（特許第5135620号、特許第5131571号、特許第5288359号）、液晶紡糸（特表2014-530964号公報）等の方法で作製することができる。 CNT11 can be produced by, for example, a floating catalyst method (Patent No. 5819888), a substrate method (Patent No. 5590603), and the floating catalyst method is preferable. Further, the CNT wire 11 is, for example, dry spinning (Patent No. 5819888, Patent No. 5990202, Patent No. 5350635), wet spinning (Patent No. 5135620, Patent No. 5131571, Patent No. 5288359), liquid crystal spinning. It can be produced by a method such as (Japanese Patent Publication No. 2014-530964).
　ＣＮＴ撚り線１０の外周面に圧縮被覆層２０を被覆する方法は、圧縮被覆層２０の熱収縮を利用して被覆する方法を利用できる。例えば、圧縮被覆層２０の材料である熱収縮チューブの内部にＣＮＴ撚り線１０を挿入し、ドライヤー等で加熱することにより熱収縮チューブが収縮してＣＮＴ撚り線１０に圧縮被覆層２０が被覆される。 As a method of coating the outer peripheral surface of the CNT stranded wire 10 with the compression coating layer 20, a method of coating by utilizing the heat shrinkage of the compression coating layer 20 can be used. For example, the CNT stranded wire 10 is inserted into the heat-shrinkable tube which is the material of the compression coating layer 20, and the heat-shrinkable tube is contracted by heating with a dryer or the like, so that the CNT stranded wire 10 is coated with the compression coating layer 20. NS.
　本実施形態におけるＣＮＴ被覆電線１は、自動車、電気機器、制御機器等の様々な分野における電力線、信号線としての電線として使用することができる。特に、ＣＮＴ被覆電線１は自動車用ワイヤハーネスとしての使用に好適である。 The CNT-coated electric wire 1 in the present embodiment can be used as an electric wire as a power line or a signal line in various fields such as automobiles, electric devices, and control devices. In particular, the CNT-coated electric wire 1 is suitable for use as a wire harness for automobiles.
　以上、本発明の実施形態について説明したが、本発明は上記実施形態に限定されるものではなく、本発明の概念に含まれるあらゆる態様を含み、本発明の範囲内で種々に改変することができる。 Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, but includes all aspects included in the concept of the present invention, and can be variously modified within the scope of the present invention. can.
　次に、本発明の実施例について説明するが、本発明はその趣旨を超えない限りこれらの実施例に限定されるものではない。 Next, examples of the present invention will be described, but the present invention is not limited to these examples as long as the gist of the present invention is not exceeded.
［実施例１～４及び比較例１～２］
　実施例１～４及び比較例１～２について、以下の製造工程により被覆電線を作製した。 [Examples 1 to 4 and Comparative Examples 1 to 2]
For Examples 1 to 4 and Comparative Examples 1 and 2, coated electric wires were produced by the following manufacturing steps.
＜導体の作製＞
　先ず、浮遊触媒法で作製したＣＮＴを用いて、湿式紡糸で表１に示す素線径を有するＣＮＴ素線を作製した。次いで、得られたＣＮＴ素線を表１に示す本数及び撚り数にて撚り合わせてＣＮＴ撚り線をそれぞれ作製した。 <Manufacturing of conductor>
First, using the CNT produced by the floating catalyst method, a CNT wire having the wire diameter shown in Table 1 was produced by wet spinning. Next, the obtained CNT strands were twisted according to the number and the number of twists shown in Table 1 to prepare CNT stranded wires, respectively.
＜ＣＮＴ被覆電線の作製＞
　ポリテトラフルオロエチレン（ＰＴＦＥ）製の熱収縮チューブを用いて、表１に示す内径を有する各熱収縮チューブの内部に各ＣＮＴ撚り線を挿入した。次いで、熱収縮チューブの収縮温度（３４０℃）で加熱して熱収縮チューブを圧縮被覆することにより、ＣＮＴ撚り線の外周に厚さ０．０５ｍｍの圧縮被覆層を形成した。また、ＰＴＦＥの曲げ弾性率をＪＩＳ　Ｋ７１７１（２０１６）に準拠して測定したところ、５５０ＭＰａであった。こうして、各実施例及び比較例におけるＣＮＴ被覆電線を作製した。 <Manufacturing of CNT-coated electric wire>
Each CNT stranded wire was inserted into each heat-shrinkable tube having an inner diameter shown in Table 1 using a heat-shrinkable tube made of polytetrafluoroethylene (PTFE). Next, the heat-shrinkable tube was compression-coated by heating at the shrinkage temperature (340 ° C.) of the heat-shrinkable tube to form a compression-coating layer having a thickness of 0.05 mm on the outer periphery of the CNT stranded wire. The flexural modulus of PTFE was measured in accordance with JIS K7171 (2016) and found to be 550 MPa. In this way, the CNT-coated electric wires in each Example and Comparative Example were produced.
　このように作製したＣＮＴ被覆電線について以下の測定及び評価を行った。 The following measurements and evaluations were performed on the CNT-coated electric wire thus produced.
＜導体径の測定＞
　熱収縮チューブが被覆される前の導体について、カッターで切断して断面を出し、マイクロスコープで観察して、導体の断面積を求めた。この断面積と同じになる円の直径（円相当直径）を求め、その値を導体径φ２（ｍｍ）とした。次いで、熱収縮チューブが被覆された後の導体も同様に導体径を計測し、その計測値を導体径φ１（ｍｍ）とした。得られた導体径φ１、φ２に基づき、導体径の比（φ１／φ２）を算出した。 <Measurement of conductor diameter>
The conductor before the heat-shrinkable tube was coated was cut with a cutter to obtain a cross section, and the cross section of the conductor was determined by observing with a microscope. The diameter of a circle (diameter equivalent to a circle) having the same cross-sectional area was obtained, and the value was defined as a conductor diameter of φ2 (mm). Next, the conductor diameter of the conductor after the heat-shrinkable tube was coated was measured in the same manner, and the measured value was defined as the conductor diameter φ1 (mm). The ratio of conductor diameters (φ1 / φ2) was calculated based on the obtained conductor diameters φ1 and φ2.
＜導体の抵抗値＞
　熱収縮チューブが被覆される前導体について、ソースメータ（ケースレー社製）を用いて１００ｍＡの電流を流したときの抵抗値を計測し、その計測値をＲ２（ｍΩ／ｍ）とした。次いで、熱収縮チューブが被覆された後の導体も同様に抵抗値を計測し、その計測値をＲ１（ｍΩ／ｍ）とした。得られた抵抗値Ｒ１、Ｒ２に基づき、導体の抵抗値の比（Ｒ１／Ｒ２）を算出した。 <Conductor resistance value>
The resistance value of the front conductor covered with the heat-shrinkable tube when a current of 100 mA was passed was measured using a source meter (manufactured by Keithley), and the measured value was defined as R2 (mΩ / m). Next, the resistance value of the conductor after the heat-shrinkable tube was coated was measured in the same manner, and the measured value was set to R1 (mΩ / m). Based on the obtained resistance values R1 and R2, the ratio of the resistance values of the conductors (R1 / R2) was calculated.
＜体積抵抗率の比＞
　被覆後の体積抵抗率ρ１（ｍΩ・ｃｍ）は、下記の式（１）から求められる。式（１）中、Ｒ１は被覆後の導体１ｍ当たりの抵抗値（ｍΩ／ｍ）、Ｓ１は被覆後の導体の断面のマイクロスコープ画像から求めた断面積（ｃｍ２）である。また、被覆前の体積抵抗率ρ２（ｍΩ・ｃｍ）は、下記の式（２）から求められる。式（２）中、Ｒ２は被覆前の導体１ｍ当たりの抵抗値（ｍΩ／ｍ）、Ｓ２は被覆前の導体の断面のマイクロスコープ画像から求めた断面積（ｃｍ２）である。得られた各体積抵抗率ρ１、ρ２に基づき、体積抵抗率の比（ρ１／ρ２）を算出した。体積抵抗率の比（ρ１／ρ２）が０．７５以下であれば導電性が向上したＣＮＴ被覆電線が得られていると評価した。 <Ratio of volume resistivity>
The volume resistivity ρ1 (mΩ · cm) after coating can be obtained from the following formula (1). In the formula (1), R1 is the resistance value (mΩ / m) per 1 m of the coated conductor, and S1 is the cross-sectional area (cm 2 ) obtained from the microscope image of the cross section of the coated conductor. The volume resistivity ρ2 (mΩ · cm) before coating is obtained from the following equation (2). In the formula (2), R2 is the resistance value (mΩ / m) per 1 m of the conductor before coating, and S2 is the cross-sectional area (cm 2 ) obtained from the microscope image of the cross section of the conductor before coating. The ratio of volume resistivity (ρ1 / ρ2) was calculated based on the obtained volume resistivityes ρ1 and ρ2. When the volume resistivity ratio (ρ1 / ρ2) was 0.75 or less, it was evaluated that a CNT-coated electric wire having improved conductivity was obtained.
　　ρ１＝（Ｒ１／１００）×Ｓ１・・・（１）
　　ρ２＝（Ｒ２／１００）×Ｓ２・・・（２） ρ1 = (R1 / 100) × S1 ... (1)
ρ2 = (R2 / 100) × S2 ... (2)
　各実施例及び比較例作製したＣＮＴ被覆電線の測定及び評価結果を、下記表１に示す。 Table 1 below shows the measurement and evaluation results of the CNT-coated electric wires produced in each example and comparative example.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示すように、導体としてのカーボンナノチューブ撚り線が圧縮被覆層としての熱収縮チューブで被覆されたＣＮＴ被覆電線において、導体の抵抗値の比（Ｒ１／Ｒ２）が０．９６未満である実施例１～４では、いずれも、体積抵抗率の比（ρ１／ρ２）が０．７以下であり、得られたＣＮＴ被覆電線は優れた導電性を示した。また、ＣＮＴ撚り線は、熱収縮チューブで直接被覆されているため、他の固定部材を使用しなくても、圧縮被覆層でＣＮＴ素線同士が強固に固定されている。そのため、実施例１～４では、導体の重さを維持したままＣＮＴ素線同士の密着性を向上することができ、ＣＮＴの軽量性を活かしつつ、導電性が向上したＣＮＴ被覆電線を得ることができた。また、実施例１～４では、少ない撚り数でも導電性を向上させることができ、さらに、ＣＮＴ素線１１の素線径がより細く、本数が多い場合に導電性の向上が顕著に発揮された。 As shown in Table 1, the ratio of the resistance values of the conductors (R1 / R2) is less than 0.96 in the CNT-coated electric wire in which the carbon nanotube stranded wire as the conductor is coated with the heat-shrinkable tube as the compression coating layer. In Examples 1 to 4, the volume resistivity ratio (ρ1 / ρ2) was 0.7 or less, and the obtained CNT-coated electric wire showed excellent conductivity. Further, since the CNT stranded wire is directly coated with the heat-shrinkable tube, the CNT strands are firmly fixed to each other by the compression coating layer without using other fixing members. Therefore, in Examples 1 to 4, it is possible to improve the adhesion between the CNT strands while maintaining the weight of the conductor, and to obtain a CNT-coated electric wire having improved conductivity while taking advantage of the light weight of the CNT. Was made. Further, in Examples 1 to 4, the conductivity can be improved even with a small number of twists, and further, when the diameter of the CNT wire 11 is smaller and the number of wires is large, the improvement in conductivity is remarkably exhibited. rice field.
　一方、導体の抵抗値の比（Ｒ１／Ｒ２）が０．９８である比較例１では、体積抵抗率の比が０．７８であり、実施例１～４と比較して導電性が劣っていた。比較例１では、十分な圧縮力でＣＮＴ撚り線に熱収縮チューブが被覆されておらず、各素線同士の密着性が十分ではないため、素線間に隙間が生じていると推察される。そのため、比較例１では優れた導電性を示すＣＮＴ被覆電線が得られなかった。 On the other hand, in Comparative Example 1 in which the ratio of the resistance values of the conductors (R1 / R2) is 0.98, the ratio of the volume resistivity is 0.78, which is inferior in conductivity as compared with Examples 1 to 4. rice field. In Comparative Example 1, it is presumed that the CNT stranded wire is not covered with the heat-shrinkable tube by a sufficient compressive force, and the adhesion between the wires is not sufficient, so that a gap is formed between the wires. .. Therefore, in Comparative Example 1, a CNT-coated electric wire showing excellent conductivity could not be obtained.
　導体の抵抗値の比（Ｒ１／Ｒ２）が０．９９である比較例２においても、比較例１と同様、実施例１～４と比較して導電性が劣っていた。また、比較例２では、導体径の比（φ１／φ２）が０．９６であり、比較例１よりも各素線同士の密着性が十分ではないため、十分な導電性を示すＣＮＴ被覆電線が得られなかった。 Even in Comparative Example 2 in which the ratio of the resistance values of the conductors (R1 / R2) was 0.99, the conductivity was inferior to that of Examples 1 to 4 as in Comparative Example 1. Further, in Comparative Example 2, the ratio of the conductor diameters (φ1 / φ2) is 0.96, and the adhesion between the strands is not sufficient as compared with Comparative Example 1, so that the CNT-coated electric wire showing sufficient conductivity is exhibited. Was not obtained.
　このように、導体としてのカーボンナノチューブ撚り線が圧縮被覆層としての熱収縮チューブで被覆されたＣＮＴ被覆電線において、導体の抵抗値の比（Ｒ１／Ｒ２）が０．９６未満であることにより、ＣＮＴの軽量性を活かしつつ、導電性が向上したカーボンナノチューブ被覆電線を提供することができる。 As described above, in the CNT-coated electric wire in which the carbon nanotube stranded wire as the conductor is coated with the heat-shrinkable tube as the compression coating layer, the ratio of the resistance values of the conductors (R1 / R2) is less than 0.96. It is possible to provide a carbon nanotube-coated electric wire having improved conductivity while taking advantage of the light weight of CNT.
　１　　カーボンナノチューブ被覆電線
　１０　カーボンナノチューブ撚り線
　１１　カーボンナノチューブ素線
　２０　圧縮被覆層 1 Carbon nanotube-coated wire 10 Carbon nanotube stranded wire 11 Carbon nanotube strand 20 Compression coating layer

Claims (11)

  1. 　導体と、前記導体を被覆する圧縮被覆層とを備え、
    　前記導体が、複数のカーボンナノチューブ素線が撚り合わされたカーボンナノチューブ撚り線であり、且つ、
    　前記圧縮被覆層が被覆される前の導体の抵抗値Ｒ２（ｍΩ／ｍ）に対する前記圧縮被覆層が被覆された後の導体の抵抗値Ｒ１（ｍΩ／ｍ）の比（Ｒ１／Ｒ２）が、０．９６未満であることを特徴とするカーボンナノチューブ被覆電線。     A conductor and a compression coating layer covering the conductor are provided.
    The conductor is a carbon nanotube stranded wire in which a plurality of carbon nanotube strands are twisted together, and the conductor is a stranded carbon nanotube wire.
    The ratio (R1 / R2) of the resistance value R1 (mΩ / m) of the conductor after the compression coating layer is coated to the resistance value R2 (mΩ / m) of the conductor before the compression coating layer is coated is determined. A carbon nanotube-coated wire characterized by being less than 0.96.
  2. 　前記圧縮被覆層が被覆される前の導体径φ２（ｍｍ）に対する前記圧縮被覆層が被覆された後の導体径φ１（ｍｍ）の比（φ１／φ２）が、０．９５未満である、請求項１に記載のカーボンナノチューブ被覆電線。 The ratio (φ1 / φ2) of the conductor diameter φ1 (mm) after the compression coating layer is coated to the conductor diameter φ2 (mm) before the compression coating layer is coated is less than 0.95. Item 1. The carbon nanotube-coated electric wire according to Item 1.
  3. 　前記カーボンナノチューブ素線の素線径が１５０μｍ以下であり、且つ、前記カーボンナノチューブ素線の本数が２０本以上である、請求項１又は２に記載のカーボンナノチューブ被覆電線。 The carbon nanotube-coated electric wire according to claim 1 or 2, wherein the wire diameter of the carbon nanotube wire is 150 μm or less, and the number of the carbon nanotube wire is 20 or more.
  4. 　前記カーボンナノチューブ素線の素線径が８０μｍ以下であり、且つ、前記カーボンナノチューブ素線の本数が５０本以上である、請求項１乃至３までのいずれか１項に記載のカーボンナノチューブ被覆電線。 The carbon nanotube-coated electric wire according to any one of claims 1 to 3, wherein the wire diameter of the carbon nanotube wire is 80 μm or less, and the number of the carbon nanotube wire is 50 or more.
  5. 　前記圧縮被覆層が熱収縮チューブである、請求項１乃至４までのいずれか１項に記載のカーボンナノチューブ被覆電線。 The carbon nanotube-coated electric wire according to any one of claims 1 to 4, wherein the compression coating layer is a heat-shrinkable tube.
  6. 　前記カーボンナノチューブ撚り線の撚り数が５０Ｔ／ｍ以上４００Ｔ／ｍ以下である、請求項１乃至５までのいずれか１項に記載のカーボンナノチューブ被覆電線。 The carbon nanotube-coated electric wire according to any one of claims 1 to 5, wherein the number of twists of the carbon nanotube stranded wire is 50 T / m or more and 400 T / m or less.
  7. 　前記圧縮被覆層の外周に更に絶縁樹脂層が設けられている、請求項１乃至６までのいずれか１項に記載のカーボンナノチューブ被覆電線。 The carbon nanotube-coated electric wire according to any one of claims 1 to 6, wherein an insulating resin layer is further provided on the outer periphery of the compression coating layer.
  8. 　自動車用ワイヤハーネスとして使用される請求項１乃至７までのいずれか１項に記載のカーボンナノチューブ被覆電線。 The carbon nanotube-coated electric wire according to any one of claims 1 to 7, which is used as a wire harness for automobiles.
  9. 　導体と、前記導体を被覆する圧縮被覆層とを備え、
    　前記導体が、複数のカーボンナノチューブ素線が撚り合わされたカーボンナノチューブ撚り線であり、
    　前記カーボンナノチューブ素線の素線径が１５０μｍ以下であり、且つ、前記カーボンナノチューブ素線の本数が２０本以上であり、
    　前記カーボンナノチューブ撚り線の撚り数が８０Ｔ／ｍ以上３００Ｔ／ｍ以下であり、且つ、
    　前記圧縮被覆層が被覆された後の導体径φ１が１．３ｍｍ以下であることを特徴とするカーボンナノチューブ被覆電線。     A conductor and a compression coating layer covering the conductor are provided.
    The conductor is a carbon nanotube stranded wire in which a plurality of carbon nanotube strands are twisted together.
    The wire diameter of the carbon nanotube wire is 150 μm or less, and the number of the carbon nanotube wire is 20 or more.
    The number of twists of the carbon nanotube stranded wire is 80 T / m or more and 300 T / m or less, and
    A carbon nanotube-coated electric wire having a conductor diameter φ1 of 1.3 mm or less after the compression coating layer is coated.
  10. 　前記カーボンナノチューブ撚り線が、５００ＭＰａ以上の曲げ弾性率を有する前記圧縮被覆層により保持されている、請求項９に記載のカーボンナノチューブ被覆電線。 The carbon nanotube-coated electric wire according to claim 9, wherein the carbon nanotube stranded wire is held by the compression coating layer having a flexural modulus of 500 MPa or more.
  11. 　前記カーボンナノチューブ素線の素線径が５０μｍ以下であり、且つ、前記カーボンナノチューブ素線の本数が１００本以上である、請求項９又は１０に記載のカーボンナノチューブ被覆電線。 The carbon nanotube-coated electric wire according to claim 9 or 10, wherein the wire diameter of the carbon nanotube wire is 50 μm or less, and the number of the carbon nanotube wire is 100 or more.
PCT/JP2021/013830 2020-03-31 2021-03-31 Carbon nanotube-coated wire WO2021201097A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015079671A (en) * 2013-10-17 2015-04-23 株式会社 Ｍｇコーポレーション Conductive wire, production method thereof, and coil
JP2019160709A (en) * 2018-03-16 2019-09-19 古河電気工業株式会社 Carbon nanotube strand, power transmission line, method for manufacturing carbon nanotube strand, and method for constructing power transmission line
WO2019189925A1 (en) * 2018-03-30 2019-10-03 古河電気工業株式会社 Carbon nanotube coated wire rod for coil, coil in which carbon nanotube coated wire rod for coil is used, and method for producing coil of carbon nanotube coated wire rod

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015079671A (en) * 2013-10-17 2015-04-23 株式会社 Ｍｇコーポレーション Conductive wire, production method thereof, and coil
JP2019160709A (en) * 2018-03-16 2019-09-19 古河電気工業株式会社 Carbon nanotube strand, power transmission line, method for manufacturing carbon nanotube strand, and method for constructing power transmission line
WO2019189925A1 (en) * 2018-03-30 2019-10-03 古河電気工業株式会社 Carbon nanotube coated wire rod for coil, coil in which carbon nanotube coated wire rod for coil is used, and method for producing coil of carbon nanotube coated wire rod

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