WO2019083029A1 - Carbon nanotube coated electric wire - Google Patents

Abstract

The present invention pertains to a carbon nanotube coated electric wire (1) having excellent heat dissipation characteristics, shape retention properties, and workability. The carbon nanotube coated electric wire (1) comprises: a carbon nanotube wire material (10) comprising at least one carbon nanotube aggregate (11) comprising a plurality of carbon nanotubes (11a); and an insulating coating layer (21) that coats the carbon nanotube wire material (10). The material constituting the insulating coating layer (21) has a Rockwell hardness of more than 22. The ratio between the thickness of the insulating coating layer (21) and the circle-equivalent diameter of the carbon nanotube wire material (10) is greater than 0.05.

Description

Carbon nanotube coated wire

The present invention relates to a carbon nanotube coated electric wire in which a carbon nanotube wire composed of a plurality of carbon nanotubes is coated with an insulating material.

Carbon nanotubes (hereinafter sometimes referred to as "CNT") are materials having various properties, and their application in many fields is expected.

For example, CNT is a single layer of a tubular body having a network structure of a hexagonal lattice, or a three-dimensional network structure composed of multiple layers arranged substantially coaxially, which is lightweight, conductive, and thermally conductive. Excellent in various properties such as elasticity, elasticity and mechanical strength. However, it is not easy to wire CNTs, and no technology has been proposed for utilizing CNTs as wires.

On the other hand, using CNT as a substitute for metal which is a filling material of a via hole formed in a multilayer wiring structure is considered. Specifically, in order to reduce the resistance of the multilayer wiring structure, multilayer CNTs in which a plurality of incisions of the multilayer CNT concentrically extended to the end far from the growth origin of the multilayer CNT are brought into contact with the conductive layer The wiring structure used as an interlayer wiring of two or more conducting wire layers is proposed (patent document 1).

As another example, in order to further improve the conductivity of the CNT material, a carbon nanotube material is proposed in which a conductive deposit made of metal or the like is formed at the electrical junction of adjacent CNT wires, such carbon It is disclosed that nanotube materials can be applied to a wide range of applications (Patent Document 2). Moreover, the heater which has a heat conductive member made from the matrix of a carbon nanotube is proposed from the outstanding thermal conductivity which a CNT wire has (patent document 3).

By the way, the covered electric wire which consists of a core wire which consists of one or a plurality of wires, and an insulation coating which covers the core is used as electric power lines and signal lines in various fields, such as a car and industrial equipment. As a material of the wire which comprises a core wire, although a copper or copper alloy is usually used from a viewpoint of an electrical property, aluminum or an aluminum alloy is proposed from a viewpoint of weight reduction in recent years. For example, the specific gravity of aluminum is about 1/3 of the specific gravity of copper, and the conductivity of aluminum is about 2/3 of that of copper (based on 100% IACS for pure copper, about 66% IACS for pure aluminum) There is a need to increase the cross-sectional area of the aluminum wire to about 1.5 times the cross-sectional area of the copper wire in order to pass the same current as the copper wire to the aluminum wire. Even if the increased aluminum wire is used, since the mass of the aluminum wire is about half of the mass of the pure copper wire, using the aluminum wire is advantageous from the viewpoint of weight reduction.

In addition, with the advancement of performance and functionality of automobiles, industrial equipment, etc., along with this, the number of installation of various electrical equipments, control equipments, etc. increases, and electric wiring bodies used for these equipments The number of wires and heat generation from the core tend to increase. Therefore, it is required to improve the heat radiation characteristics of the electric wire without impairing the insulation property by the insulation coating. On the other hand, in order to improve the fuel consumption of moving bodies such as automobiles for environmental protection, weight reduction of the wire is also required.

Furthermore, development of a high-performance coated wire to which the coated wire is imparted with additional functions in addition to conductivity and lightness is also considered. As one of such functions, shape improvement capable of maintaining the shape of the coated electric wire is required to improve the workability. Since the CNT wire has much higher flexibility than the metal wire, the wire can be deformed into various shapes. On the other hand, the CNT wire does not have a plastic deformation region like a metal wire, and it is difficult to maintain its shape because of its ease of deformation. Therefore, it was necessary to newly consider the shape retention of the coated wire in which the insulating coating is bonded to the CNT wire.

Unexamined-Japanese-Patent No. 2006-120730 Japanese Patent Application Publication No. 2015-523944 JP, 2015-181102, A

An object of the present invention is to provide a carbon nanotube coated electric wire which is excellent in heat radiation characteristics, shape retention, and workability.

The aspect of the present invention comprises a carbon nanotube wire comprising one or more carbon nanotube aggregates composed of a plurality of carbon nanotubes, and an insulating covering layer covering the carbon nanotube wire, and the insulating covering layer is constituted The material has a Rockwell hardness of greater than 22, and a ratio of the thickness of the insulating covering layer to the equivalent circle diameter of the carbon nanotube wire of greater than 0.05.

In the aspect of the present invention, the Rockwell hardness of the material is 25 or more and 120 or less, and the ratio of the thickness of the insulating covering layer to the equivalent circle diameter of the carbon nanotube wire is 0.060 or more and 0.600. It is a carbon nanotube coated electric wire which is the following.

The aspect of this invention is a carbon nanotube coated electric wire whose circle equivalent diameter of the single wire which comprises the said carbon nanotube wire is 0.090 mm or more and 10 mm or less.

The aspect of this invention is a carbon nanotube coated electric wire whose circle equivalent diameter of the single wire which comprises the said carbon nanotube wire is 0.180 mm or more and 0.5 mm or less.

In the aspect of the present invention, the carbon nanotube wire comprises a plurality of the aggregate of carbon nanotubes, and the half width Δθ of an azimuth angle in an azimuth plot by small angle X-ray scattering showing the orientation of the plurality of aggregate of carbon nanotubes is 60 It is a carbon nanotube coated electric wire which is less than °°.

According to an aspect of the present invention, the q value of the peak top at the (10) peak of the scattering intensity by X-ray scattering indicating the density of the plurality of carbon nanotubes is 2.0 nm ⁻¹ or more and 5.0 nm ⁻¹ or less, width Δq is a carbon nanotube covered electric wire is 0.1 nm ^-1 or 2.0 nm ^-1 or less.

Unlike a metal core wire, a carbon nanotube wire using a carbon nanotube as a core wire is anisotropic in thermal conduction, and heat is preferentially conducted in the longitudinal direction as compared with the radial direction. That is, since the carbon nanotube wire has anisotropic heat dissipation characteristics, it has excellent heat dissipation characteristics as compared to metal core wires. Therefore, the design of the insulating covering layer for covering the core wire using carbon nanotubes needs to be designed differently from the insulating covering layer of the metal core wire. According to the aspect of the present invention, the carbon nanotube wire has a Rockwell hardness of greater than 22 of the material forming the insulation covering layer, and the ratio of the thickness of the insulation covering layer to the equivalent circle diameter of the carbon nanotube wire is By being larger than 0.05, it is possible to obtain a carbon nanotube coated electric wire which is excellent in heat radiation characteristics, shape retention, and workability.

According to the aspect of the present invention, the Rockwell hardness of the material is 25 or more and 120 or less, and the ratio of the thickness of the insulating covering layer to the equivalent circle diameter of the carbon nanotube wire is 0.060 or more and 0.600 or less As a result, the shape of the carbon nanotube coated wire can be more easily maintained.

According to the aspect of the present invention, when the equivalent circle diameter of the single wire constituting the carbon nanotube wire is 0.090 mm or more and 10 mm or less, the carbon nanotube wire is excellent in the carbon nanotube coated wire while fully utilizing the strength of the carbon nanotube wire. Heat dissipation characteristics can be imparted. Furthermore, when the equivalent circle diameter of a single wire constituting the carbon nanotube wire is 0.180 mm or more and 0.5 mm or less, shape retentivity and workability can be improved even if the insulating coating layer is relatively thin. The heat dissipation characteristics can also be improved.

According to the aspect of the present invention, the carbon nanotube or carbon nanotube in the carbon nanotube wire has the half width Δθ of the azimuth angle in the azimuth plot by small angle X-ray scattering of the carbon nanotube aggregate in the carbon nanotube wire being 60 ° or less. Since the aggregates can be present at high density, the carbon nanotube wire exhibits excellent heat dissipation characteristics.

According to an aspect of the present invention, q values of the peak top in (10) the peak of scattering intensity by X-ray scattering of aligned carbon nanotubes is at 2.0 nm ^-1 or 5.0 nm ^-1 or less, and the half width Δq There 0.1nm by ^-1 to 2.0 nm ^-1 or less, because it has a carbon nanotube has high orientation, exhibits excellent heat dissipation properties of carbon nanotube wires.

It is an explanatory view of a carbon nanotube covering electric wire concerning an example of an embodiment of the present invention. It is an explanatory view of a carbon nanotube wire used for a carbon nanotube covering electric wire concerning an example of an embodiment of the present invention. The figure (a) is a figure showing an example of the two-dimensional scattering image of the scattering vector q of a plurality of carbon nanotube aggregates by SAXS, and the figure (b) is the position of transmission X-ray in the azimuth plot two-dimensional scattering image. Is a graph showing an example of azimuth angle-scattering intensity of an arbitrary scattering vector q having an origin of. 15 is a graph showing the relationship between q value and strength by WAXS of a plurality of carbon nanotubes constituting a carbon nanotube aggregate.

Below, the carbon nanotube covering electric wire concerning the example of an embodiment of the present invention is explained using a drawing.

As shown in FIG. 1, a carbon nanotube coated electric wire (hereinafter sometimes referred to as "CNT coated electric wire") 1 according to an embodiment of the present invention may be referred to as a carbon nanotube wire (hereinafter referred to as "CNT wire") 2.) The outer circumferential surface of the insulating coating layer 21 is coated on the outer circumferential surface 10. That is, the insulating coating layer 21 is coated along the longitudinal direction of the CNT wire 10. In the CNT-coated electric wire 1, the entire outer peripheral surface of the CNT wire 10 is covered with the insulating covering layer 21. Further, in the CNT-coated electric wire 1, the insulating covering layer 21 is in an aspect in direct contact with the outer peripheral surface of the CNT wire 10. In FIG. 1, the CNT wire 10 is a strand (single wire) formed of one CNT wire 10. However, the CNT wire 10 may be in the form of a stranded wire obtained by twisting a plurality of CNT wires 10. By setting the CNT wire 10 in the form of a stranded wire, the equivalent circle diameter and the cross-sectional area of the CNT wire 10 can be appropriately adjusted. Further, since the CNT wire 10 is a stranded wire, the strength of the CNT wire 10 is higher than that of a single wire, and disconnection of the CNT wire 10 caused by the deformation of the CNT wire 10 can be suppressed more reliably.

As shown in FIG. 2, the CNT wire 10 is sometimes referred to as a carbon nanotube assembly (hereinafter referred to as "CNT assembly") composed of a plurality of CNTs 11a, 11a, ... having a layer structure of one or more layers. 11) It is formed by bundling one or more of eleven. Here, the CNT wire means a CNT wire having a ratio of CNT of 90% by mass or more. In addition, plating and a dopant are excluded in calculation of the CNT ratio in a CNT wire. In FIG. 2, the CNT wire 10 has a configuration in which a plurality of CNT assemblies 11 are bundled. The longitudinal direction of the CNT assembly 11 forms the longitudinal direction of the CNT wire 10. Therefore, the CNT assembly 11 is linear. The plurality of CNT aggregates 11, 11,... In the CNT wire 10 are arranged substantially in the same longitudinal direction. Therefore, the plurality of CNT aggregates 11, 11, ... in the CNT wire 10 are oriented.

The equivalent circle diameter of the single wire (wire) constituting the CNT wire 10 is preferably 0.090 mm or more and 10 mm or less. The equivalent circle diameter of the single wire constituting the CNT wire 10 is preferably 0.090 mm, more preferably 0.180 mm, from the viewpoint of making full use of the strength. In particular, by making the equivalent circle diameter of a single wire constituting the CNT wire 10 larger, the rigidity of the CNT wire 10 itself is enhanced. Therefore, even if the insulating covering layer 21 is relatively thin, the shape retentivity and the workability can be improved. On the other hand, the upper limit value of the circle equivalent diameter of the single wire constituting the CNT wire 10 is preferably 10 mm, more preferably 3 mm, still more preferably 1 mm, and particularly preferably 0.5 mm from the viewpoint of imparting excellent heat dissipation characteristics. In particular, when the equivalent circle diameter of the single wire constituting the CNT wire 10 is 0.5 mm or less, it is possible to suppress the surface area relative to the volume of the single wire from being reduced excessively, and to improve the heat dissipation characteristics. When the CNT wire 10 is a stranded wire, the equivalent circle diameter of the CNT wire 10 as the stranded wire is preferably 0.090 mm or more and 15 mm or less. The lower limit is preferably 0.090 mm, more preferably 0.400 mm, from the viewpoint of making full use of the strength of the CNT wire 10 as a stranded wire, and on the other hand, the excellent heat dissipation characteristics of the CNT wire 10 as a single wire The upper limit thereof is preferably 15 mm, more preferably 3 mm, and still more preferably 1 mm, from the viewpoint of not impairing

The CNT assembly 11 is a bundle of CNTs 11 a having a layer structure of one or more layers. The longitudinal direction of the CNTs 11 a forms the longitudinal direction of the CNT assembly 11. The plurality of CNTs 11a, 11a,... In the CNT assembly 11 are arranged substantially in the same longitudinal direction. Therefore, the plurality of CNTs 11a, 11a,... In the CNT assembly 11 are oriented. The equivalent circle diameter of the CNT assembly 11 is, for example, 20 nm or more and 1000 nm or less, and more typically 20 nm or more and 80 nm or less. The width dimension of the outermost layer of the CNTs 11 a is, for example, 1.0 nm or more and 5.0 nm or less.

The CNTs 11 a constituting the CNT assembly 11 are cylindrical bodies having a single-layer structure or a multi-layer structure, and are respectively referred to as SWNT (single-walled nanotubes) and MWNT (multi-walled nanotubes). In FIG. 2, for convenience, only the CNTs 11 a having a two-layer structure are described, but the CNT aggregate 11 includes CNTs having a three-layer structure or more and a CNT having a single-layer structure. It may be formed of CNT having a layer structure of three or more layer structure or CNT having a layer structure of single layer structure.

The CNT 11a having a two-layer structure is a three-dimensional network structure in which two cylindrical bodies T1 and T2 having a network structure of a hexagonal lattice are arranged substantially coaxially, and is called DWNT (Double-walled nanotube) . The hexagonal lattice, which is a structural unit, is a six-membered ring having a carbon atom at its apex, and adjacent to another six-membered ring, these are continuously bonded.

The properties of the CNTs 11a depend on the chirality of the above-mentioned cylindrical body. The chirality is roughly classified into an armchair type, a zigzag type, and a chiral type. The armchair type is metallic, the zigzag type is semiconductive and semimetallic, and the chiral type is semiconductive and semimetallic. Therefore, the conductivity of the CNTs 11a largely differs depending on which chirality the tubular body has. In the CNT aggregate 11 constituting the CNT wire 10 of the CNT-coated electric wire 1, it is preferable to increase the proportion of armchair-type CNTs 11a exhibiting metallic behavior, in order to further improve the conductivity.

On the other hand, it is known that chiral CNTs 11a exhibit metallic behavior by doping chiral CNTs 11a exhibiting semiconducting behavior with substances having different electron donating properties or electron accepting properties (different elements). . In addition, in general metals, the doping of different elements causes scattering of conduction electrons inside the metal to lower the conductivity, but similar to this, the CNT 11a showing metallic behavior is doped with different elements. If it does, it causes a decrease in conductivity.

Thus, the doping effects on the CNTs 11a showing the behavior of the metal and the CNTs 11a showing the behavior of the semiconductivity are in a trade-off relationship from the viewpoint of the conductivity, and thus the behavior of the metal theoretically appears. It is desirable that the CNTs 11a and the CNTs 11a exhibiting the behavior of the semiconductor property are separately manufactured, and the doping process is performed only on the CNTs 11a exhibiting the behavior of the semiconductor property, and then these are combined. In the case where the CNTs 11a exhibiting metallic behavior and the CNTs 11a exhibiting semiconductive behavior are produced in a mixed state, it is preferable to select the layer structure of the CNTs 11a in which the doping process with different elements or molecules is effective. Thereby, the conductivity of the CNT wire 10 formed of a mixture of the CNTs 11a exhibiting metallic behavior and the CNTs 11a exhibiting semiconductive behavior can be further improved.

For example, a CNT having a smaller number of layers, such as a two-layer structure or a three-layer structure, is relatively more conductive than a CNT having a larger number of layers, and when doped, the two-layer structure or three layers The doping effect in the structured CNT is the highest. Therefore, in order to further improve the conductivity of the CNT wire 10, it is preferable to increase the proportion of CNTs having a two-layer structure or a three-layer structure. Specifically, the ratio of CNTs having a two-layer structure or a three-layer structure to the entire CNTs is preferably 50 number% or more, and more preferably 75 number% or more. The proportion of CNTs having a two-layer structure or a three-layer structure can be determined by observing and analyzing the cross section of the CNT assembly 11 with a transmission electron microscope (TEM) and measuring the number of layers of 50 to 200, preferably 100 CNTs. It can be calculated by measuring.

Next, the orientation of the CNTs 11 a and the CNT aggregate 11 in the CNT wire 10 will be described.

Fig.3 (a) is a figure which shows an example of the two-dimensional scattering image of the scattering vector q of several CNT assembly 11,11, ... by small angle X ray scattering (SAXS), and FIG.3 (b) is shown. 6 is a graph showing an example of an azimuth plot showing the relationship between azimuth angle and scattering intensity of an arbitrary scattering vector q whose origin is the position of transmitted X-ray in a two-dimensional scattering image.

SAXS is suitable for evaluating structures of several nm to several tens of nm in size. For example, the orientation of the CNT 11a having an outer diameter of several nm and the orientation of the CNT aggregate 11 having an outer diameter of several tens nm by analyzing the information of the X-ray scattering image by the following method using SAXS Can be evaluated. For example, when an X-ray scattering image is analyzed for the CNT wire 10, as shown in FIG. 3A, the x component of the scattering vector q (q = 2π / d: d is lattice spacing) of the CNT assembly 11 The y component q _y is relatively narrowly distributed rather than q _x . Moreover, as a result of analyzing the azimuth plot of SAXS about the same CNT wire 10 as FIG. 3 (a), half value width (DELTA) (theta) of the azimuth angle in the azimuth plot shown in FIG.3 (b) is 48 degrees. From these analysis results, in the CNT wire 10, it can be said that the plurality of CNTs 11a, 11a,... And the plurality of CNT aggregates 11, 11,. As described above, since the plurality of CNTs 11a, 11a,... And the plurality of CNT aggregates 11, 11,. It is easy to be dissipated while transmitting smoothly along the longitudinal direction of the. Therefore, the CNT wire 10 can adjust the heat radiation route in the longitudinal direction and the cross-sectional direction of the diameter by adjusting the orientation of the CNTs 11 a and the CNT aggregate 11, and therefore, the heat radiation characteristics superior to the metal core wire. Demonstrate. In addition, orientation refers to the angle difference of the vector of the CNT and the CNT assembly inside with respect to the vector V in the longitudinal direction of the stranded wire produced by twist-collecting CNTs.

The CNT wire 10 is obtained by obtaining an orientation of a certain value or more indicated by the half width Δθ of the azimuth angle in an azimuth plot of small angle X-ray scattering (SAXS) indicating the orientation of a plurality of CNT aggregates 11, 11,. In order to impart excellent heat dissipation characteristics, the half value width Δθ of the azimuth angle is preferably 60 ° or less, and particularly preferably 50 ° or less.

Next, the arrangement structure and the density of the plurality of CNTs 11 a constituting the CNT assembly 11 will be described.

FIG. 4 is a graph showing the q value-intensity relationship by WAXS (wide-angle X-ray scattering) of the plurality of CNTs 11a, 11a,.

WAXS is suitable for evaluating the structure or the like of a substance having a size of several nm or less. For example, by analyzing the information of the X-ray scattering image by the following method using WAXS, it is possible to evaluate the density of the CNTs 11a having an outer diameter of several nm or less. As a result of analyzing the relationship between the scattering vector q and the intensity for any one CNT aggregate 11, as shown in FIG. 4, it can be seen that the peak of (10) appears around q = 3.0 nm- ¹ to 4.0 nm- ¹ . The lattice constant value estimated from the q value at the peak top is measured. Based on the measured values of the lattice constant and the diameter of the CNT aggregate observed by Raman spectroscopy or TEM, it is confirmed that the CNTs 11a, 11a,... Form a hexagonal close-packed structure in plan view. can do. Therefore, the diameter distribution of the plurality of CNT aggregates is narrow in the CNT wire 10, and the plurality of CNTs 11a, 11a,... Form a hexagonal close-packed structure by having a regular arrangement, ie, a high density. It can be said that it exists in high density.

In this way, the plurality of CNT aggregates 11, 11... Have good orientation, and further, the plurality of CNTs 11a, 11a,. Because they are arranged at high density, the heat of the CNT wire 10 is easily dissipated while being smoothly transmitted along the longitudinal direction of the CNT aggregate 11. Therefore, the CNT wire rod 10 can adjust the heat dissipation route in the longitudinal direction and the cross-sectional direction of the diameter by adjusting the arrangement structure and density of the CNT aggregate 11 and the CNTs 11a, so it is superior to a metal core wire. Demonstrates heat dissipation characteristics.

From the viewpoint of imparting excellent heat dissipation characteristic by obtaining a high density, multiple CNT11a, 11a, of intensity by X-ray scattering shows a density of ··· (10) q value of the peak top in the peak 2.0 nm ^{- 1} or 5.0 nm ^-1 or less, and is preferably a half-value width [Delta] q (FWHM) is 0.1 nm ^-1 or 2.0 nm ^-1 or less.

The orientation of the CNT aggregate 11 and the CNTs 11 and the alignment structure and density of the CNTs 11a are adjusted by appropriately selecting the spinning method such as dry spinning, wet spinning, liquid crystal spinning, and spinning conditions of the spinning method described later. be able to.

Next, the insulating covering layer 21 covering the outer surface of the CNT wire 10 will be described.

As a material of the insulation coating layer 21, a thermoplastic resin can be mentioned, for example. As a thermoplastic resin, for example, polypropylene (Young's modulus: 1.1 to 1.4, Rockwell hardness: 85 to 110), cellulose acetate (Young's modulus: 0.46 to 2.8, Rockwell hardness: 34 to 125), polyamide (Young's modulus: 1.1 to 4.2, Rockwell hardness: 103 to 118), trifluorochloroethylene resin (PCTFE) (Young's modulus :, Rockwell height: 75 to 95), tetrafluorinated And ethylene hexafluoride / propylene copolymer (FEP) (Young's modulus: 0.35, Rockwell hardness: 25) and the like can be mentioned. These may be used alone or in combination of two or more.

The thickness of the insulating covering layer 21 is not particularly limited, but is preferably 0.002 mm or more and 1.0 mm or less. The lower limit of the thickness of the insulating covering layer 21 is 0.006 mm because the insulating covering layer 21 covered with the CNT 10 wire does not deteriorate even if the shape of the CNT 10 wire is deformed while sufficiently protecting the CNT 10 wire. Preferably, 0.08 mm is particularly preferred. On the other hand, the upper limit value of the thickness of the C insulating covering layer 21 is that the insulating covering layer 21 can correspond to the deformation as the shape of the CNT 10 wire deforms while the strength of the insulating covering layer 21 is sufficiently maintained. 0 mm is preferable and 0.8 mm is more preferable

The insulating covering layer 21 may be a single layer as shown in FIG. 1, or alternatively, may be two or more layers. When the insulating covering layer 21 is composed of a plurality of layers, the thickness of the insulating covering layer 21 is calculated by the sum of the layer thicknesses of the respective insulating covering layers 21. In addition, a layer of a thermosetting resin may be further provided between the outer surface of the CNT wire 10 and the insulating coating layer 21 as necessary.

In the CNT-coated electric wire 1, the Rockwell hardness of the material constituting the insulating covering layer 21 is larger than 22 and the ratio of the thickness of the insulating covering layer 21 to the equivalent circle diameter of the CNT wire 10 is larger than 0.05 . When the Rockwell hardness of the material is greater than 22 and the ratio is greater than 0.05, the hardness of the insulating covering layer 21 is large, and the insulating covering layer 21 is also relatively thick, so the shape of the CNT wire 10 Even if it deform | transforms, the shape of the CNT coating | coated electric wire 1 is hold | maintained appropriately, without the insulation coating layer 21 breaking. As a result, the CNT-coated wire 1 exhibits excellent shape retention, and the CNT-coated wire 1 can be provided with excellent workability. In addition, the Rockwell hardness of the material is 25 or more and 120 or less, and the ratio of the thickness of the insulating covering layer 21 to the equivalent circle diameter of the CNT wire 10 is 0.060 or more and 0.600 or less preferable. As a result, the edge covering layer 21 can be controlled in a well-balanced manner within a range that is neither too hard nor too thick, and the shape of the CNT-coated wire 1 can be more easily maintained. As a result, the excellent shape retentivity of the CNT-coated electric wire 1 can be maintained, and stable workability can be imparted. In addition, by appropriately controlling the thickness of the insulating covering layer 21, it is possible to obtain the CNT-coated electric wire 1 having excellent heat dissipation characteristics without deteriorating the insulation reliability. Furthermore, the ratio of the thickness of the insulating covering layer 21 to the equivalent circle diameter of the CNT wire 10 is more preferably 0.015 or more. Thereby, the insulation reliability of the CNT-coated wire 1 can be improved.

The Rockwell hardness means a measured value of R scale, and can be measured based on JIS 7202-2. If the Rockwell hardness is 22 or less, the hardness of the insulating covering layer 21 is insufficient, and it is difficult to maintain the shape of the CNT-coated wire 1. Further, also when the thickness ratio of the insulating covering layer 21 to the equivalent circle diameter of the CNT wire 10 is 0.05 or less, the hardness of the insulating covering layer 21 is likewise insufficient, and the shape of the CNT covered electric wire 1 Hard to hold By properly controlling both the Rockwell hardness of the insulating covering layer 21 used for the CNT covered electric wire 1 and the ratio of the thickness of the insulating covering layer 21 to the equivalent circle diameter of the CNT wire 10, the CNT covered electric wire 1 is excellent It is possible to exhibit the heat radiation characteristics and the shape retentivity, and to provide the CNT-coated electric wire 1 with excellent workability.

In the CNT-coated electric wire 1, the ratio of the cross-sectional area in the radial direction of the insulating covering layer 21 to the cross-sectional area in the radial direction of the CNT wire 10 is preferably in the range of 0.05 or more and 0.7 or less. When the ratio of the cross-sectional area is in the range of 0.05 or more and 0.7 or less, the core wire is the CNT wire 10 which is lighter compared to copper, aluminum, etc., and the thickness of the insulating covering layer 21 is thinned. Since it can do, the outstanding thermal radiation characteristic to the heat of CNT wire material 10 can be acquired, without spoiling insulation reliability. Moreover, weight reduction of the electric wire coat | covered with the insulation coating layer 21 can be achieved.

In addition, in the case where the shape maintenance in the longitudinal direction may be difficult with the CNT wire 10 alone, the CNT-covered electric wire 1 can be obtained by covering the outer surface of the CNT wire 10 with the insulating covering layer 21 at the ratio of the cross sectional area. The shape in the longitudinal direction can be maintained, and deformation such as bending is easy. Therefore, the CNT-coated wire 1 can be formed in a shape along a desired wiring path.

Furthermore, since fine irregularities are formed on the outer surface of the CNT wire 10, adhesion between the CNT wire 10 and the insulating coating layer 21 is improved as compared to a coated wire using a core wire of aluminum or copper. It can improve and it can control exfoliation between CNT wire 10 and insulating covering layer 21.

When the ratio of the cross-sectional area is in the range of 0.05 or more and 0.7 or less, the cross-sectional area in the radial direction of the CNT wire 10 is not particularly limited, but for example, 0.005 mm ² or more and 80 mm ² or less is preferable, 0 .01Mm ² or 10 mm ² and more preferably less, 0.03 mm ² or more 6.0 mm ² or less is particularly preferred. Further, the cross-sectional area in the radial direction of the insulating cover layer 21 is not particularly limited, from the viewpoint of further improving the insulation reliability, for example, preferably 0.00025Mm ² or 56 mm ² or less, 0.0005 mm ² or more 7.0mm ² or less is especially preferable. The cross-sectional area can be measured, for example, from an image of a scanning electron microscope (SEM) observation. Specifically, after obtaining an SEM image (100 times to 10,000 times) of a radial cross section of the CNT-coated wire 1, the CNT wire 10 was penetrated from the area of the portion surrounded by the outer periphery of the CNT wire 10. The sum of the area obtained by subtracting the area of the material of the insulating covering layer 21, the area of the portion of the insulating covering layer 21 covering the outer periphery of the CNT wire 10 and the area of the material of the insulating covering layer 21 intruding inside the CNT wire 10 is The cross-sectional area in the radial direction of the CNT wire 10 and the cross-sectional area in the radial direction of the insulating coating layer 21 are respectively used. The radial cross-sectional area of the insulating covering layer 21 also includes the resin that has entered between the CNT wires 10.

Young's modulus of CNT is higher than that of aluminum and copper used as conventional core wires. While the Young's modulus of aluminum is 70.3 GPa and the Young's modulus of copper is 129.8 GPa, the Young's modulus of CNT has a value of 300 to 1500 GPa, which is more than double. Therefore, in the CNT-coated electric wire 1, a material having a high Young's modulus (a thermoplastic resin having a high Young's modulus) can be used as the material of the insulating covering layer 21 as compared to a coated electric wire using aluminum and copper as core wires. Therefore, excellent wear resistance can be imparted to the insulating coating layer 21 of the CNT-coated electric wire 1, and the CNT-coated electric wire 1 exhibits excellent durability.

As described above, the Young's modulus of CNT is higher than that of aluminum and copper used as conventional core wires. Therefore, in the CNT-coated electric wire 1, the ratio of the Young's modulus of the material constituting the insulating coating layer to the Young's modulus of the core is smaller than the ratio of the Young's modulus of the coated electric wire using aluminum and copper as the core. Therefore, in the CNT-coated electric wire 1, peeling of the CNT wire 10 and the insulating covering layer 21 and cracking of the insulating covering layer 21 can be suppressed even when being repeatedly bent as compared with the covered electric wire using aluminum or copper as the core wire.

The ratio of the Young's modulus of the material constituting the insulating coating layer 21 to the Young's modulus of the CNT wire 10 is not particularly limited, but the lower limit of the ratio of the Young's modulus is the CNT wire even if the CNT-coated wire 1 is repeatedly bent. Since the insulating covering layer 21 follows 10 to prevent the insulating covering layer 21 from peeling off from the CNT wire 10, 0.0001 is preferable, and even if the CNT coated electric wire 1 is bent for a long period of time, from the CNT wire 10 In order to prevent the insulation coating layer 21 from peeling, 0.01 is more preferable, and 0.05 is particularly preferable. On the other hand, the upper limit value of the ratio of Young's modulus is preferably 3.0 from the viewpoint of preventing the occurrence of cracks in the insulating covering layer 21 even if the CNT-coated wire 1 is repeatedly bent, and the CNT-coated wire 1 for a long time 1.0 is more preferable, and 0.7 is particularly preferable, from the viewpoint of preventing the occurrence of cracks in the insulating covering layer 21 even when the B is bent.

The thickness in the direction orthogonal to the longitudinal direction of the insulating covering layer 21 (that is, in the radial direction) is preferably uniform from the viewpoint of improving the mechanical strength such as the abrasion resistance of the CNT-coated electric wire 1. Specifically, the uneven thickness ratio of the insulating coating layer 21 is preferably, for example, 50% or more from the point of imparting excellent abrasion resistance, and particularly preferably 80% or more from the point of further improving the abrasion resistance. Here, “a non-uniform thickness ratio” means α = (thickness of the insulation coating layer 21 for every 10 cm at an arbitrary 1.0 m on the center side of the CNT-coated electric wire 1 in the radial direction). The minimum value / the maximum value of the thickness of the insulation coating layer 21) × 100 is calculated, and the value obtained by averaging the α values calculated in each cross section is meant. In addition, the thickness of the insulating covering layer 21 can be measured, for example, from an image of SEM observation by circular approximation of the CNT wire 10. Here, the longitudinal center side refers to a region located at the center as viewed from the longitudinal direction of the line.

The uneven thickness ratio of the insulating covering layer 21 is, for example, when the insulating covering layer 21 is formed on the outer peripheral surface of the CNT wire 10 by extrusion coating, the tension in the longitudinal direction of the CNT wire 10 passing through the die during the extrusion process is increased. Can improve it.

Next, an example of a method of manufacturing the CNT-coated electric wire 1 according to the embodiment of the present invention will be described. The CNT-coated electric wire 1 can be manufactured by first manufacturing the CNTs 11 a, forming the CNT wire 10 from the obtained plurality of CNTs 11 a, and coating the outer circumferential surface of the CNT wire 10 with the insulating covering layer 21.

The CNTs 11a can be manufactured by a method such as a floating catalyst method (Japanese Patent No. 5819888), a substrate method (Japanese Patent No. 5590603), or the like. The strands of the CNT wire 10 can be manufactured by dry spinning (Japanese Patent No. 5819888, Patent No. 5990202, Japanese Patent No. 5350635), wet spinning (Japanese Patent No. 5135620, Japanese Patent No. 5131571, Japanese Patent No. 5288359) Table 2014-530964) etc. can be produced.

As a method of covering the insulating covering layer 21 on the outer peripheral surface of the CNT wire 10 obtained as described above, a method of covering an insulating covering layer on a core wire of aluminum or copper can be used. For example, raw materials of the insulating covering layer 21 And a method of melting and extruding around the CNT wire 10 and coating it.

The CNT-coated electric wire 1 according to the embodiment of the present invention can be used as a general electric wire such as a wire harness, and a cable may be produced from the general electric wire using the CNT-coated electric wire 1.

Next, examples of the present invention will be described, but the present invention is not limited to the following examples as long as the purpose of the present invention is not exceeded.

Examples 1 to 19 and Comparative Examples 1 to 5
First, the dry spinning method (Japanese Patent No. 5819888) or the wet spinning method (Japanese Patent No. 5135620, Japanese Patent No. 5131571, Japanese Patent No. 5288359) directly spins the CNT produced by the floating catalyst method. The single wire of the CNT wire material of the predetermined | prescribed circle equivalent diameter shown in Table 1 in each Example and a comparative example was obtained. The stranded wire was manufactured by adjusting the number of obtained CNT wires and appropriately twisting.

Method of Coating Insulation Coating Layer on Outer Surface of CNT Wire Using the resin type shown in Table 1 below, an insulation coating layer is formed by extrusion coating around the conductor using a conventional extrusion machine for wire production Then, CNT-coated electric wires used in the examples and comparative examples in Table 1 below were produced.

Polypropylene (Sumitomo Chemical Corporation Sumitomo Nobren, Rockwell hardness: 92)
Cellulose Acetate (Acetyl, Daicel Finechem, Rockwell Hardness: 65)
Polyamide (Toray Industries Amilan, Rockwell hardness: 100)
FEP (Daikin's Neoflon FEP, Rockwell hardness: 25)
PTFE (tetrafluoroethylene resin) (manufactured by Asahi Kasei Corp. Fluon, Rockwell hardness: 20)

(A) Measurement of Circle Equivalent Diameter of CNT Wire and Single Wire After cutting a radial cross section of the CNT wire with an ion milling apparatus (IM4000 manufactured by Hitachi High-Technologies Corporation), a scanning electron microscope (SU 8020 manufactured by Hitachi High-Technologies Corporation): The cross-sectional area of the CNT wire in the radial direction was measured from the SEM image obtained at 100 to 10,000 times). The same measurement was repeated every 10 cm at an arbitrary 1.0 m on the center side in the longitudinal direction of the CNT-coated wire, and the average value was taken as the cross-sectional area of the CNT wire in the radial direction. In addition, as a cross-sectional area of a CNT wire, the resin which got in the inside of a CNT wire was not included in measurement. Next, the circle equivalent diameter of the CNT wire and the single wire was calculated from the value of the obtained cross-sectional area.

(B) Measurement of Thickness of Insulating Coating Layer After cutting a radial cross section of the CNT wire with an ion milling apparatus (IM 4000 manufactured by Hitachi High-Technologies Corporation), a scanning electron microscope (SU 8020 manufactured by Hitachi High-Technologies Corporation, magnification: 100- The radial thickness of the insulating covering layer was measured from the SEM image obtained at 10,000 times). The same measurement is repeated every 10 cm at an arbitrary 1.0 m on the longitudinal center side of the CNT coated wire, and the circle (CNT wire equivalent circle) having the same area as the radial cross section of the CNT wire and the diameter of the CNT coated wire Circles with the same area as the directional cross-sectional area (CNT-coated wire equivalent circles) were obtained respectively, and the difference from the radius of the CNT wire equivalent circle was determined from the radius of the CNT-coated wire equivalent circle, and the thickness of the insulating covering layer was determined. .

(C) Measurement of Half Angle Width Δθ of Azimuth Angle by SAXS X-ray scattering measurement was carried out using a small angle X-ray scattering device (Aichi Synchocroton), and the half width Δθ of azimuth angle was determined from the obtained azimuth plot.

(D) Measurement of peak top q value and half width Δq by WAXS Wide-angle X-ray scattering measurement was performed using a wide-angle X-ray scattering apparatus (Aichi Synchrotron), and the q-value-intensity graph obtained shows ) The q value of the peak top at the peak and the half width Δq were determined.

The results of the above measurements of the CNT-coated wire are shown in Table 1 below.

The following evaluation was performed about the CNT coated electric wire produced as mentioned above.

(1) Heat dissipation characteristics Four terminals were connected to both ends of a 100 cm CNT-coated wire, and resistance measurement was performed by the four-terminal method. At this time, the applied current was set to 2000 A / cm ² and the time change of the resistance value was recorded. The rate of increase was calculated by comparing the resistance value at the start of measurement and after 10 minutes. Since the resistance of the CNT wire increases in proportion to the temperature, it can be judged that the smaller the rate of increase in resistance, the better the heat dissipation characteristics. If the increase rate of resistance is less than 5%, it will be "◎", if the increase rate of resistance is 5% or more and less than 15%, "〇", if the increase rate of resistance is 15% or more and less than 30% If it was "O" or more, it was evaluated that it was excellent in the heat dissipation characteristic.

(2) Insulating reliability The method was performed in accordance with JIS C3215-0-1, item 13.3. If the test results meet Grade 2 or higher listed in Table 13.3 in Clause 13.3, "◎", Grade 1 meets "「 "and those less than any grade are marked" X ". If it is more than "o", it evaluated that insulation reliability is favorable.

(3) Shape-retaining property A portion of 1 cm from each end of a CNT-coated wire with a length of 12 cm was held with a jig and held in a horizontal state for 10 minutes with a tension of 100 gf. Subsequently, only the jig at one end was removed, and it was measured how many cm the other end dropped from the other end. Ten similar tests are carried out, and if there is no drop by 1 cm or more, "◎", if 1 cm or more drops by 1 or 2 "o", if 1 cm or more drops by 3 or more, "x" If it is "O" or more, it was evaluated that shape retentivity is excellent.

(4) Workability A conduit with an inner diameter of 54 mm and a length of 1 m was vertically stood. Subsequently, a 2 m long CNT coated wire was prepared. From under the conduit, it was passed through the CNT-coated wire, and the CNT-coated wire was taken out from above. The test is performed 10 times, and if the number of times the CNT-coated wire can be taken out from the top without bending in the wire tube is 8 or more, “、”, and if 5 to 7 times “、”, 4 If it was less than the number of times, it was evaluated as "x", and if it was "o" or more, it was evaluated that the workability was excellent.

The results of the above evaluation are shown in Table 1 below.

As shown in Table 1 above, the Rockwell hardness of the material constituting the insulating coating layer is greater than 22, and the ratio of the thickness of the insulating coating layer to the equivalent circle diameter of the carbon nanotube wire is greater than 0.05. In Examples 1 to 19, a carbon nanotube-coated electric wire was obtained in which the heat radiation characteristics, the shape retention, and the workability were all excellent even when the resin type was any of polypropylene, cellulose acetate, polyamide, and FEP. In addition, a CNT-coated wire excellent in insulation reliability was obtained. In particular, in Examples 2 to 3, 4 to 5, 8 to 14, and 17 to 19, a CNT-coated electric wire having more excellent shape retention and workability was obtained.

Further, from the comparison between Example 7 and Examples 8 to 9, it is possible to obtain a CNT-coated electric wire in which the shape retention and the workability are further improved as the circle equivalent diameter of the single wire is thicker. Furthermore, from the comparison between Example 16 and Example 17, a CNT-coated electric wire with improved shape retention and workability was obtained as the insulating covering layer is thicker.

Further, in Examples 1 to 19, the half value width Δθ of the azimuth angle was 60 ° or less. Therefore, in the CNT wire of each of Examples 1 to 12, the CNT aggregate had excellent orientation. In Examples 1 ~ 19, q values of the peak top in (10) peak intensity are both at 2.0 nm ^-1 or 5.0 nm ^-1 or less, the half width Δq are all 0.1nm ^-1 or more and 2.0 nm ^-1 or less. Therefore, in the CNT wires of Examples 1 to 19, the CNTs also had excellent orientation.

On the other hand, in Comparative Examples 1 and 2 in which the Rockwell hardness of the material constituting the insulating coating layer is 22 or less, the shape retention can not be obtained, and the workability is also inferior. Furthermore, in Comparative Example 1 in which the ratio of the thickness of the insulating covering layer to the equivalent circle diameter of the CNT wire is 0.05 or less, the insulation reliability is also inferior.

Further, in Comparative Examples 3 to 5, in which the ratio of the thickness of the insulating covering layer to the equivalent circle diameter of the CNT wire is 0.05 or less, although the Rockwell hardness of the material constituting the insulating covering layer exceeds 22. The insulation reliability, the shape retention, and the workability were all inferior or the heat dissipation characteristics were inferior.

Reference Signs List 1 carbon nanotube-coated electric wire 10 carbon nanotube wire rod 11 carbon nanotube aggregate 11a carbon nanotube 21 insulating coating layer

Claims (6)

A carbon nanotube wire consisting of one or more carbon nanotube aggregates composed of a plurality of carbon nanotubes, and an insulating covering layer covering the carbon nanotube wire,
The Rockwell hardness of the material constituting the insulating covering layer is greater than 22 and
The carbon nanotube coated electric wire wherein the ratio of the thickness of the insulating covering layer to the equivalent circle diameter of the carbon nanotube wire is greater than 0.05. The Rockwell hardness of the material is 25 or more and 120 or less, and
The carbon nanotube coated electric wire according to claim 1, wherein the ratio of the thickness of the insulating covering layer to the equivalent circle diameter of the carbon nanotube wire is 0.060 or more and 0.600 or less. The carbon nanotube coated electric wire according to claim 1 or 2 whose circle equivalent diameter of a single wire which constitutes said carbon nanotube wire is 0.090 mm or more and 10 mm or less. The carbon nanotube coated electric wire according to claim 3 whose circle equivalent diameter of a single wire which constitutes said carbon nanotube wire is 0.180 mm or more and 0.5 mm or less. The carbon nanotube wire is composed of a plurality of the aggregate of carbon nanotubes, and the half width Δθ of azimuth angle in an azimuth plot by small angle X-ray scattering showing the orientation of the plurality of aggregate of carbon nanotubes is 60 ° or less. The carbon nanotube coated wire according to any one of 1 to 4. Q value of the peak top in (10) the peak of scattering intensity by X-ray scattering shows a density of a plurality of the carbon nanotubes is at 2.0 nm ^-1 or 5.0 nm ^-1 or less, and the half width Δq is 0.1nm carbon nanotubes coated wire according to any one of claims 1 to 5 is ^-1 or 2.0 nm ^-1 or less.

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