JP7348934B2 - carbon nanotube wire - Google Patents

Description

The present invention relates to a method for manufacturing a carbon nanotube wire constituted by a plurality of carbon nanotubes, and a carbon nanotube wire manufactured by the method in which a plurality of carbon nanotube aggregates are oriented.

Carbon nanotubes are materials with various properties and are expected to be applied to many fields.

For example, carbon nanotubes are three-dimensional network structures consisting of a single layer of cylindrical bodies with a hexagonal lattice network structure, or multiple layers arranged approximately coaxially, and are lightweight, conductive, and heat-resistant. Excellent properties such as conductivity and mechanical strength. However, it is not easy to make carbon nanotubes into wires, and no technology has been proposed for using carbon nanotubes as wires.

As a method for producing a carbon nanotube wire, for example, a dispersion containing carbon nanotubes and a thickener selected from the group consisting of carboxymethylcellulose and polyvinylpyrrolidone is discharged into a coagulation bath, spun, and drawn. A method is disclosed in which the thickener is removed by treating the drawn yarn with a solvent in which the thickener can be dissolved (Patent Document 1).

Japanese Patent Application Publication No. 2010-168679

In the above conventional technology, a dispersion liquid is discharged into a coagulation bath using an extrusion spinning method to obtain a spun yarn by wet spinning, and the spun yarn is stretched by a drawing machine while blowing hot air with a dryer. By doing so, carbon nanotube wires are obtained. In the above-mentioned prior art, the stretching ratio is disclosed to be about 1.1 to 3 times, and when the spinning yarn is drawn while being heated after being taken out of the coagulation liquid, the CNTs will almost complete the coagulation process. They are in a strongly agglomerated state, and even if force is applied in the linear direction, the arrangement of the CNTs hardly changes; if more force is applied than necessary, the CNTs tend to break starting at points where interaction and entanglement between the CNTs is weak. For this reason, it is difficult to increase the drawing ratio with the above conventional technology, and the orientation of the plurality of carbon nanotube aggregates that make up the carbon nanotube wire becomes insufficient, which limits the improvement of the mechanical strength of the carbon nanotube wire. be. In addition, even if the carbon nanotube wire rod after the spinning treatment is stretched while applying heat, the spun yarn is only slightly stretched, which improves the orientation of the plurality of carbon nanotube aggregates that make up the carbon nanotube wire rod. It is difficult.

An object of the present invention is to provide a carbon nanotube wire in which a plurality of carbon nanotube aggregates can be highly oriented and the mechanical strength of the carbon nanotube wire can be increased.

In order to achieve the above object, the method for producing a carbon nanotube wire according to the present invention includes a step of discharging a dispersion containing a plurality of carbon nanotubes into a coagulation liquid to produce a carbon nanotube filament (A); The carbon nanotube fiber (B) is produced by stretching the carbon nanotube fiber (A) in the coagulation liquid.

A conveying speed V2 of a second conveying section disposed on the downstream side with respect to the stretching direction of the carbon nanotube filament (A) is made larger than a conveying speed V1 of the first conveying section disposed on the upstream side with respect to the stretching direction. It is preferable that the carbon nanotube filament (A) be stretched while being held in both the first conveyance section and the second conveyance section.

The first transport section is a first pair of nipping rollers disposed in the coagulation liquid, and the second transport part is a second pair of nip rollers disposed in the coagulation liquid, It is preferable that V2/V1, which is the ratio of the conveying speed V2 of the second pair of nipping rollers to the conveying speed V1 of the first pair of nipping rollers, is 3 or more and 10 or less.

In order to achieve the above object, the carbon nanotube wire of the present invention is a carbon nanotube wire formed by bundling a plurality of carbon nanotube aggregates composed of a plurality of carbon nanotubes, the carbon nanotube wire comprising a plurality of carbon nanotubes. It is characterized in that the half width Δθ of the azimuth angle in the azimuth plot obtained by small-angle X-ray scattering, which indicates the orientation of the aggregate, is 25° or more and less than 50°.

In the cross section of the carbon nanotube wire, the width at half maximum of the azimuth angle Δθin, which indicates the orientation of the plurality of carbon nanotube aggregates forming the inside of the carbon nanotube wire, is It is preferable that Δθout/Δθin, which is the ratio of the half width Δθout of the azimuth angle indicating the orientation of the carbon nanotube aggregate, is larger than 0.85.

According to the present invention, a dispersion containing a plurality of carbon nanotubes is discharged into a coagulation liquid to form a carbon nanotube filament (A), and the carbon nanotube filament (A) is stretched in the coagulation liquid. Since the carbon nanotube filament (B) is formed by using CNT filament (B), the plurality of carbon nanotube aggregates constituting the carbon nanotube filament (B) can be highly oriented, and the carbon nanotube wire obtained from the CNT filament (B) can be Mechanical strength can be increased.

1 is a flowchart illustrating an example of a method for manufacturing a carbon nanotube wire according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a step of subjecting the carbon nanotube filament (A) to a stretching process in a coagulation liquid in the manufacturing method of FIG. 1 .

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a flowchart showing an example of a method for manufacturing a carbon nanotube wire according to this embodiment. In this embodiment, as a method for manufacturing a carbon nanotube wire, carbon nanotubes are spun by a wet spinning method.
As shown in Figure 1, first, carbon nanotubes (hereinafter referred to as "CNTs") produced using methods such as the floating catalyst method (Patent No. 5819888) or the substrate method (Patent No. 5590603) are prepared. and a solvent to prepare a dispersion containing a plurality of CNTs (Step S1). Examples of the solvent for the dispersion include organic solvents such as toluene, N-methylpyrrolidone (NMP), sodium dodecylsulfonate, dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), and methyl isobutyl ketone (MIBK). , an aqueous solution containing a surfactant is used. As the surfactant, anionic surfactants such as alkylbenzene sulfonates and alkyl sulfates, and cationic surfactants such as tetraalkylammonium halides can be used. The content of carbon nanotubes in the dispersion is, for example, 0.05 to 20% by mass.

The dispersion may contain a thickener to increase viscosity. As the thickener, for example, carboxymethyl cellulose (CMC), polyvinylpyrrolidone (PVP), glycerin, and ethylene glycol are used. The content of the thickener in the dispersion is, for example, 0.05 to 5% by mass.

Next, as shown in FIG. 2, the dispersion liquid containing a plurality of CNTs is discharged from a discharge part 2 such as a syringe into a coagulation bath 1 filled with a coagulation liquid to form carbon nanotube filaments (hereinafter referred to as " (also referred to as "CNT yarn") (A) (Step S2). When the dispersion liquid is discharged into the coagulation liquid, it comes into contact with the coagulation liquid, thereby forming a plurality of linear CNT aggregates. At this time, the CNT yarn (A) may have a structure in which a plurality of CNT aggregates are twisted together, or the longitudinal direction of the plurality of CNT aggregates and the longitudinal direction of the CNT yarn (A) may be the same or substantially the same. may include states that are identical. That is, the CNT yarn (A) may include a plurality of CNT aggregates that are bundled without being twisted together.

As the coagulating liquid, those having different affinities with the dispersion solvent are appropriately selected and used, such as NMP, N,N-dimethylacetamide (DMA), DMF, water, methanol, ethanol, and propanol.

Next, as shown in FIG. 2, the CNT yarn (A) is stretched in a coagulation bath 1 to produce a carbon nanotube yarn (hereinafter also referred to as "CNT yarn") (B) (step S3). . This stretching process is performed continuously in the coagulating liquid, for example, after discharging the dispersion liquid into the coagulating liquid in the above-mentioned discharging process.

As a method for stretching the CNT yarn (A), for example, in the coagulation bath 1, the first conveying section 3 is placed on the upstream side with respect to the stretching direction X of the CNT yarn (A), and the first conveying section 3 is placed on the downstream side with respect to the stretching direction The second transport units 4 are respectively arranged. Then, the conveying speed V2 of the second conveying section disposed on the downstream side with respect to the stretching direction is also made larger, and the CNT yarn (A) is stretched while being held between both the first conveying section 3 and the second conveying section 4. By making the conveying speed V2 of the second conveying section 4 higher than the conveying speed V1 of the first conveying section 3, tensile stress is applied to the CNT fiber (A) along its longitudinal direction in the coagulation bath 1. I can do it.

Here, in the above-mentioned conventional technology, it is difficult to increase the stretching ratio because the CNTs that have undergone the solidification process are stretched in a strongly aggregated state. On the other hand, in the present invention, the CNTs and CNT aggregates are stretched in a coagulation liquid, and the CNT aggregates are surrounded by the dispersion medium, so that even if force is applied in the linear direction, the CNT aggregates do not interact with each other through the dispersion medium. Since the arrangement can be changed, a high stretching ratio can be achieved without breaking compared to the conventional technology.
In addition, in the solidification process of CNT wires, the dispersion liquid usually seeps out from the outer periphery of the CNT wire and solidification progresses, so the density of the plurality of CNT aggregates that make up the inside of the CNT wire is lower than that of the outer periphery of the CNT wire. The density tends to be smaller than the density of the plurality of CNT aggregates that make up the CNT aggregate. Therefore, in the case of the conventional method in which a drawing process is performed after a coagulation process, in a CNT wire that has been completely solidified by the coagulation process, the density of the plurality of CNT aggregates that constitute the inside of the CNT wire constitutes the outer peripheral part of the CNT wire. It is assumed that the density is smaller than the density of multiple CNT aggregates. In addition, if a CNT wire with this density difference is heated and stretched, the inside of the CNT wire where the density of the CNT aggregates is small is less likely to receive the force from the adjacent CNT aggregates, and the CNT aggregates are The orientation is lower than that in the outer periphery where the density is high.

On the other hand, when the CNT filament (A) is subjected to stretching treatment in a coagulation liquid as in the present embodiment, when the coagulation gradually progresses from the outer circumference to the inside of the CNT filament (A), the CNT filament (A) Since the yarn (A) is stretched, the decrease in the density of the multiple CNT aggregates forming the inside of the CNT yarn (A) is suppressed, and the multiple CNT aggregates forming the inside of the CNT yarn (A) are suppressed. The difference between the density of the CNT fiber (A) and the density of the plurality of CNT aggregates forming the outer peripheral part of the CNT yarn (A) becomes smaller. Furthermore, since the CNT yarn (A) is not heated during the stretching process, it is possible to suppress the progress of coagulation at the outer periphery. Therefore, in the above stretching process, the longitudinal direction of the plurality of CNT aggregates constituting the outer peripheral part of the CNT filament (A) and the longitudinal direction of the plurality of CNT aggregates constituting the inside of the CNT filament (A). The coagulation of the plurality of CNT aggregates is completed when the long axis directions of the plurality of CNT aggregates in the entire CNT filament (A) are substantially aligned. This improves the overall orientation of the plurality of CNT aggregates constituting the CNT filament (B).

The first conveying section 3 is a first pair of nipping rollers 3a and 3b disposed in a coagulating liquid such as the coagulating bath 1, and the second conveying section 4 is a pair of first holding rollers 3a and 3b disposed in a coagulating liquid such as the coagulating bath 1. A second pair of nipping rollers 4a and 4b are arranged inside. The first pair of nipping rollers 3a and 3b are configured to be rotatable at a predetermined number of revolutions in the coagulation liquid, and the transport speed of the CNT yarn (A) as the conveyed object is set based on the predetermined number of revolutions. Or adjusted. The second pair of pinching rollers 4a and 4b are similarly configured to be rotatable at a predetermined rotation speed, and the conveyance speed of the CNT raw yarn (A) as the conveyed object is set or adjusted based on the predetermined rotation speed. Ru.

When the conveyance speed of the first pair of pinch rollers 3a, 3b is V1, and the conveyance speed of the second pair of pinch rollers 4a, 4b is V2, the conveyance speed V1 of the first pair of pinch rollers 3a, 3b is V2/V1, which is the ratio of the conveyance speed V2 of the second pair of nipping rollers 4a and 4b, is, for example, 3 or more and 10 or less, preferably 4 or more and 10 or less, and more preferably 6 or more and 10 or less. As a result, the tensile stress applied to the CNT filament (A) increases, and the density of the multiple CNT aggregates constituting the inside of the CNT filament (A) and the outer periphery of the CNT filament (A) increase. The difference between the densities of the plurality of CNT aggregates forming the CNT filament (B) can be further reduced, and the orientation of the plurality of CNT aggregates forming the CNT filament (B) is further improved.

After passing through the above steps, the CNT yarn (B) is dried and heated if necessary, thereby manufacturing the CNT wire according to the present embodiment.

[Configuration of CNT wire]
The CNT wire manufactured by the above manufacturing method is formed by bundling a plurality of CNT aggregates each composed of a plurality of CNTs. Here, the CNT wire means a CNT wire in which the proportion of CNT is 90% by mass or more. Note that in calculating the CNT ratio in the CNT wire, the mass of plating and dopant is excluded. The longitudinal direction of the CNT aggregate forms the longitudinal direction of the CNT wire. Therefore, the CNT aggregate is linear. The plurality of CNT aggregates in the CNT wire are arranged with their long axes substantially aligned. Therefore, the plurality of CNT aggregates in the CNT wire are oriented. The equivalent circle diameter of the CNT wire, which is a wire, is not particularly limited, but is, for example, 0.01 mm or more and 1.0 mm or less. Further, the CNT wire may be configured by bundling a plurality of CNT aggregates. The equivalent circle diameter of one twisted CNT wire is not particularly limited, but is, for example, 0.05 mm or more and 5 mm or less. A CNT wire made of a plurality of CNT wires is also referred to as a CNT wire, and in this case, the upper limit of the cross-sectional area is not limited.

The CNT wire may have a configuration in which a plurality of CNT aggregates are twisted together, or may include a state in which the longitudinal direction of the CNT aggregate and the longitudinal direction of the CNT wire are the same or substantially the same. That is, the CNT wire may include a plurality of CNT aggregates that are bundled without being twisted together.

A CNT aggregate is a bundle of CNTs having a layered structure of one or more layers. The longitudinal direction of the CNTs forms the longitudinal direction of the CNT aggregate. The plurality of CNTs in the CNT aggregate are arranged with their long axes substantially aligned. Therefore, the plurality of CNTs in the CNT aggregate are oriented. The equivalent circle diameter of the CNT aggregate is, for example, 20 nm or more and 1000 nm or less, more typically 20 nm or more and 80 nm or less. The width dimension of the outermost layer of CNT is, for example, 1.0 nm or more and 20 nm or less.

The CNTs constituting the CNT aggregate are cylindrical bodies having a single-walled structure or a multi-layered structure, and are called SWNTs (single-walled nanotubes) and MWNTs (multi-walled nanotubes), respectively. The CNT aggregate may also include CNTs having a layer structure of three or more layers or CNTs having a single layer structure, and CNTs having a layer structure of three or more layers or a layer of a single layer structure. It may be formed from CNTs having a structure.

A CNT having a two-layer structure has a three-dimensional network structure in which two cylindrical bodies having a hexagonal lattice network structure are arranged substantially coaxially, and is called a DWNT (Double-walled nanotube). The hexagonal lattice, which is a constituent unit, is a six-membered ring with a carbon atom at its apex, and these six-membered rings are adjacent to and continuously bonded to other six-membered rings.

Next, the orientation of CNTs and CNT aggregates in the CNT wire will be explained.

Small-angle X-ray scattering (SAXS) is suitable for evaluating structures with a size of several nanometers to several tens of nanometers. For example, the orientation of a CNT aggregate with an outer diameter of several tens of nanometers can be evaluated by using SAXS and analyzing information on an X-ray scattering image in the following manner. Since the plurality of CNT aggregates have good orientation, mechanical strength such as tensile strength can be further increased compared to conventional CNT wires. Note that the orientation refers to the angular difference between the vectors of the internal CNTs and the CNT aggregate with respect to the vector V in the longitudinal direction of a twisted wire produced by twisting CNTs together.

In this embodiment, the mechanical stability of CNT wires is improved by obtaining an orientation higher than a certain level, which is indicated by the half-width Δθ of the azimuth angle in the azimuth plot of small-angle X-ray scattering (SAXS), which indicates the orientation of multiple CNT aggregates. In order to increase the strength, the half width Δθ of the azimuth angle is 25° or more and less than 50°, preferably 29° or more and 45° or less.

In addition, in the present embodiment, in the cross section of the CNT wire, a plurality of CNTs constituting the outer circumferential portion of the CNT wire The ratio Δθout/Δθin, which is the half-width Δθout of the azimuth angle indicating the orientation of the aggregate, is greater than 0.85, preferably 0.89 or more. C.N.T.
The inside of the wire refers to the area inside the half of the equivalent circle radius from the center of the cross-section in the width direction, and the outer periphery of the CNT wire refers to the area outside the inside of the CNT wire and inside the cross-section in the width direction. Refers to the area outside half of the circle equivalent radius from the center of the circle. When Δθout/Δθin is 0.85 or more, the difference between the orientation of CNT aggregates inside the CNT wire and the orientation of multiple CNT aggregates at the outer periphery becomes small, and the tensile strength of the CNT wire, etc. mechanical properties are improved.

The CNT wire may be provided with an insulating coating layer covering the outer periphery thereof. In that case, the CNT wire and the insulating coating layer constitute a CNT-coated wire.

As the material for the insulating coating layer, materials used for the insulating coating layer of a covered electric wire using a metal as a core wire can be used, and examples thereof include thermoplastic resins and thermosetting resins. Examples of thermoplastic resins include polytetrafluoroethylene (PTFE), polyethylene, polypropylene, polyacetal, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyether ether ketone, polycarbonate, polyamide, polyvinyl chloride, polymethyl methacrylate, and polyurethane. etc. can be mentioned. Furthermore, examples of the thermosetting resin include polyimide, phenol resin, and the like. These may be used alone or in an appropriate mixture of two or more.

When the CNT-covered wire is a high-voltage wire, the thermoplastic resin is preferably polyethylene or polyvinyl chloride, and particularly preferably crosslinked polyethylene or soft polyvinyl chloride.

The insulating coating layer may be a single layer, or alternatively may be two or more layers. Furthermore, a thermosetting resin layer may be further provided on the insulating coating layer, if necessary. Moreover, the thermosetting resin may contain a filler having a fiber shape or a particle shape.

The insulating coating layer is formed, for example, over the entire length of the CNT wire so as to cover the entire outer periphery of the CNT wire. As a method for forming the insulation coating layer, a method of coating an aluminum or copper core wire with the insulation coating layer can be used. For example, thermoplastic resin, which is the raw material for the insulation coating layer, is melted and extruded around the CNT wire. Examples include a method of coating or a method of coating around the CNT wire.

The CNT wire or CNT-covered electric wire according to this embodiment can be used as a general electric wire such as a wire harness, and a cable may be made from a general electric wire using the CNT wire or CN-covered electric wire.

As described above, according to the present embodiment, a dispersion containing a plurality of CNTs is discharged into a coagulation liquid to form a CNT filament (A), and the CNT filament (A) is stretched in the coagulation liquid. Since the CNT filament (B) is formed by processing, the multiple CNT aggregates constituting the CNT filament (B) can be highly oriented, and the mechanical properties of the CNT wire obtained from the CNT filament (B) can be improved. Strength can be increased.

In addition, the CNT wire manufactured by the above manufacturing method is formed by bundling a plurality of CNT aggregates composed of a plurality of CNTs, and the azimuth is determined by small-angle X-ray scattering, which indicates the orientation of the plurality of CNT aggregates. Since the half-value width Δθ of the azimuth angle in the plot is 25° or more and less than 50°, the orientation of the plurality of CNT aggregates constituting the CNT wire is good, and a CNT wire with high mechanical strength can be provided. .

Next, examples of the present invention will be described, but the present invention is not limited to the following examples unless it exceeds the spirit of the present invention.

(Example 1)
First, CNTs were prepared using a floating catalyst method, and an aqueous solution containing 0.5% by mass of each of CNTs and sodium dodecylsulfonate was prepared, and a dispersion was obtained by ultrasonication for 30 minutes.

Next, ethanol was prepared as a coagulation liquid, and the dispersion liquid containing a plurality of CNTs was discharged from a syringe into a coagulation bath to form a CNT filament (A). Next, the conveying speed V1 of the first pair of pinching rollers, the conveying speed V2 of the second pair of pinching rollers, and V2/V1 are set to the values shown in Table 1, respectively, and the CNT yarn (A) is The CNT fiber (A) was stretched in a coagulation liquid by being pinched and conveyed in this order by a first pair of pinch rollers and a second pair of pinch rollers, to produce a CNT fiber (B). Thereafter, the CNT yarn (B) was dried to obtain a CNT wire having an equivalent circular diameter of 50 μm to 300 μm.

(Example 2)
A CNT wire was produced in the same manner as in Example 1, except that the conveyance speed V2 and V2/V1 of the second pair of nipping rollers were changed.

(Example 3)
A CNT wire was produced in the same manner as in Example 1, except that the conveyance speed V2 and V2/V1 of the second pair of nipping rollers were changed.

(Example 4)
A CNT wire was produced in the same manner as in Example 1, except that the conveyance speed V2 and V2/V1 of the second pair of nipping rollers were changed.

(Example 5)
A CNT wire was produced in the same manner as in Example 3, except that the conveyance speed V1 of the first pair of pinch rollers and the conveyance speed V2 of the second pair of pinch rollers were changed.

(Example 6)
A CNT wire was produced in the same manner as in Example 4, except that the conveyance speed V1 of the first pair of pinch rollers and the conveyance speed V2 of the second pair of pinch rollers were changed.

(Comparative example 1)
A CNT wire was produced in the same manner as in Example 1, except that the conveyance speed V2 and V2/V1 of the second pair of nipping rollers were changed.

(Comparative example 2)
According to the manufacturing method described in JP-A No. 2010-168679, a CNT wire rod was produced by performing a stretching process while heating at a stretching ratio of 1.2 times.

Next, the following measurements and evaluations were performed on the CNT wire produced as described above.

(a) Orientation degree of CNT aggregate The CNT wire was sliced thinly to a thickness of 50 μm in the cross-sectional direction using a focused ion beam (FIB). Using a small-angle X-ray scattering device, X-rays are incident perpendicularly to the plane of this slice, and the azimuth plot (azimuth angle) of the obtained scattering peak is fitted with a Gaussian or Lorentzian function to determine the azimuth angle. The half width Δθ was calculated.

(b) Orientation internal/external ratio Using microbeam small-angle X-rays, inject X-rays with a beam size of 10 μm in the direction perpendicular to the plane of the slice piece cut out from the CNT wire in the same manner as above, The half width Δθ of the azimuth angle was determined in the same manner as described above. The half-width of the azimuth angle when X-rays were incident on the outer periphery and inside of the CNT wire on the above surface was defined as Δθout and Δθin, respectively, and Δθout/Δθin was evaluated as the internal/external orientation ratio α.

(c) Tensile strength Using a tensile tester, the tensile strength in the longitudinal direction of the CNT wire was measured. If the tensile strength at break is greater than 600 MPa, it is very good. "◎". If it is greater than 500 MPa and less than 600 MPa, it is good. "△" if it is greater than 400 MPa and less than 500 MPa. The following cases were marked as defective: "x".

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

As shown in Table 1, in Example 1, V2/V1, which is the ratio of the conveying speed V2 of the second pair of pinching rollers to the conveying speed V1 of the first pair of pinching rollers, is 10, and the degree of orientation is The mechanical strength was extremely good, with an orientation angle of 29°, an inside-outside orientation ratio of 0.95, and a tensile strength of 714 MPa.

In Example 2, V2/V1 was 6, the degree of orientation was 37°, the internal/external orientation ratio was 0.93, the tensile strength was 625 MPa, and the mechanical strength was extremely good.

In Example 3, V2/V1 was 4, the degree of orientation was 44°, the internal/external orientation ratio was 0.89, the tensile strength was 511 MPa, and the mechanical strength was good.

In Example 4, V2/V1 was 3, the degree of orientation was 48°, the internal/external orientation ratio was 0.91, the tensile strength was 402 MPa, and the mechanical strength was generally good.

In Example 5, V1 is 0.4 m/min, V2 is 1.6 m/min, V2/V1 is 4, the degree of orientation is 42°, the internal/external orientation ratio is 0.94, and the tensile strength is 523 MPa. , mechanical strength was good.

In Example 6, V1 was 0.4 m/min, V2 was 1.2 m/min, V2/V1 was 3, the degree of orientation was 47°, the internal/external orientation ratio was 0.88, and the tensile strength was 419 MPa. , the mechanical strength was generally good.

On the other hand, in Comparative Example 1, the conveying speed V1 of the first pair of pinching rollers is the same as that of Example 1, but the conveying speed V2 of the second pair of pinching rollers is smaller than that of Example 1, and V2/V1 is 1. .5, the degree of orientation was 50°, the internal/external orientation ratio was 0.83, the tensile strength was 376 MPa, and the mechanical strength was poor.

In addition, in Comparative Example 2, when the stretching process was performed while heating at a stretching ratio of 1.2 times, the degree of orientation was 52°, the internal/external orientation ratio was 0.85, the tensile strength was 345 MPa, and the mechanical strength was was inferior.

1 Coagulation bath 2 Discharge section 3 First conveying section 3a, 3a First pair of pinching rollers 4 Second conveying section 4a, 4a Second pair of pinching rollers X Stretching direction (A) CNT raw yarn (B) CNT raw thread

Claims (1)

A carbon nanotube wire formed by bundling a plurality of carbon nanotube aggregates composed of a plurality of carbon nanotubes,
The half-width Δθ of the azimuth angle in an azimuth plot by small-angle X-ray scattering indicating the orientation of the plurality of carbon nanotube aggregates is 25° or more and less than 50°,
In the cross section of the carbon nanotube wire, the width at half maximum of the azimuth angle Δθin, which indicates the orientation of the plurality of carbon nanotube aggregates forming the inside of the carbon nanotube wire, is Δθout/Δθin, which is the ratio of the half-width Δθout of the azimuth angle indicating the orientation of the carbon nanotube aggregate, is larger than 0.85;
The carbon nanotube wire is a wire obtained by drying carbon nanotube yarn,
Since the plurality of carbon nanotube aggregates are solidified in the entire carbon nanotube filament so that the longitudinal directions of the plurality of carbon nanotube aggregates are aligned, the longitudinal directions of the plurality of carbon nanotube aggregates in the carbon nanotube wire are aligned. has been
A carbon nanotube wire having a tensile strength at break of greater than 500 MPa.

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