Carbon nanotube assembly wire, carbon nanotube assembly wire bundle, and carbon nanotube structure

Abstract

The carbon nanotube assembly wire is a carbon nanotube assembly wire including a plurality of carbon nanotubes, and the carbon nanotubes are aligned with an orientation degree of 0.9 or more and 1 or less.

Description

[Technical field]

[0001] The present disclosure relates to a carbon nanotube assembly wire, a carbon nanotube assembly wire bundle, and a carbon nanotube structure. This application claims priority to Japanese Patent Application No. 2018-245684 filed on December 27, 2018, and Japanese Patent Application No. 2019-030645 filed on February 22, 2019. All contents of the Japanese patent application are incorporated herein by reference. [Background technology]

[0002] Carbon nanotubes (hereinafter referred to as CNTs), which have a cylindrical structure of graphene sheets in which carbon atoms are bonded in a hexagonal shape, are a material that has excellent properties, being one-fifth the weight of copper, 20 times stronger than steel, and having metallic conductivity. For this reason, electric wires using carbon nanotubes are expected to contribute to reducing the weight, size, and corrosion resistance of automobile motors in particular.

[0003] Carbon nanotubes can be obtained by a vapor phase growth method, as disclosed in Patent Document 1 (JP Patent Publication No. 2005-330175), in which a fine catalyst such as iron is heated while a raw material gas containing carbon is supplied to grow carbon nanotubes from the catalyst. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-330175 A [Non-patent literature]

[0005] [Non-Patent Document 1] Agnieszka Lekawa-Raus et al. “Electrical Properties of Carbon Nanotube Based Fibers and Their Future Use in Electrical Wiring”, Advanced Functional Materials, Vo. 24, pp3661-3682(2014).DOI:10.1002 / adfm.201303716 Summary of the Invention

[0006] The carbon nanotube assembly wire of the present disclosure is A carbon nanotube assembly wire including a plurality of carbon nanotubes, The carbon nanotubes are aligned with a degree of orientation of 0.9 or more and 1 or less in the carbon nanotube assembly wire.

[0007] The carbon nanotube assembly wire bundle of the present disclosure includes: A carbon nanotube assembly wire bundle including a plurality of the carbon nanotube assembly wires described above, In the carbon nanotube assembly wire, the carbon nanotubes are aligned with an orientation degree of 0.9 or more and 1 or less, In the carbon nanotube assembly wire bundle, the carbon nanotube assembly wires are oriented with an orientation degree of 0.8 or more and 1 or less.

[0008] The carbon nanotube structure of the present disclosure is Carbon nanotubes, and catalyst particles attached to both ends of the carbon nanotubes; The catalyst particles are carbon nanotube structures having a particle diameter of 0.6 nm or more and less than 30 nm. [Brief description of the drawings]

[0009] [Figure 1]FIG. 1 is a diagram illustrating a typical configuration example of a carbon nanotube aggregate wire according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a transmission electron microscope (TEM) image of an example of a carbon nanotube assembly wire according to an embodiment of the present disclosure. [Diagram 3] FIG. 3 is a binarized image of the TEM image in FIG. [Figure 4] FIG. 4 is an image obtained by Fourier transforming the binarized image of FIG. [Diagram 5] FIG. 5 is a graph showing the relationship between the orientation angle and the orientation strength obtained from the Fourier transform image of FIG. [Figure 6] FIG. 6 is a diagram showing an example of a carbon nanotube used in an embodiment of the present disclosure. [Figure 7] FIG. 7 is a diagram illustrating a representative configuration example of a carbon nanotube assembly wire bundle according to an embodiment of the present disclosure. [Figure 8] FIG. 8 is a scanning electron microscope (SEM) image of an example of the CNT assembly wire bundle according to this embodiment. [Figure 9] FIG. 9 is an image obtained by binarizing the SEM image of FIG. [Figure 10] FIG. 10 is an image obtained by Fourier transforming the binarized image of FIG. [Figure 11] FIG. 11 is a graph showing the relationship between the orientation angle and the orientation strength obtained from the Fourier transform image of FIG. [Figure 12] FIG. 12 is an SEM image of an example of a carbon nanotube assembly wire bundle according to an embodiment of the present disclosure. [Figure 13] FIG. 13 is a diagram illustrating an orientation region of a CNT-aggregate wire bundle according to an embodiment of the present disclosure. [Figure 14] FIG. 14 is a diagram illustrating a typical configuration example of a carbon nanotube assembly wire manufacturing apparatus according to an embodiment of the present disclosure. [Figure 15] FIG. 15 is a diagram for explaining an electric field generating unit of a carbon nanotube assembly wire manufacturing apparatus according to another embodiment of the present disclosure. [Figure 16] FIG. 16 is a diagram for explaining a magnetic field generating unit of a carbon nanotube assembly wire production apparatus according to another embodiment of the present disclosure. [Figure 17] FIG. 17 is an image of the carbon nanotube assembly wire of Sample 1. [Figure 18] FIG. 18 is a diagram illustrating a typical configuration example of a carbon nanotube assembly wire production apparatus according to another embodiment of the present disclosure. [Figure 19] FIG. 19 is a diagram illustrating an example of a mist generating unit. [Figure 20] FIG. 20 is a diagram showing another example of the mist generating section. [Figure 21] FIG. 21 is a diagram showing another example of the mist generating section. [Figure 22] FIG. 22 is a diagram showing a typical configuration example of a carbon nanotube structure manufacturing apparatus according to an embodiment of the present disclosure. [Figure 23] FIG. 23 is a transmission electron microscope (TEM) image of a carbon nanotube structure according to one embodiment of the present disclosure. [Figure 24] FIG. 24 is a transmission electron microscope (TEM) image of the carbon nanotube structure of sample 5-2. [Diagram 25] FIG. 25 is an image of the carbon nanotube assembly wire of Sample 5-2. [Figure 26] FIG. 26 is a graph showing the particle size distribution of catalyst particles in the carbon nanotube aggregate wire of sample 5-2. [Figure 27] FIG. 27 is a graph showing the results of a break test on the carbon nanotube assembly wire bundle of Sample 3. In FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Problem that this disclosure aims to solve] Carbon nanotubes produced using current carbon nanotube production technology have diameters of approximately 0.4 nm to 20 nm and lengths of up to 55 cm. In order to use carbon nanotubes as electric wires or high-strength materials, longer carbon nanotubes are required, and technology to lengthen carbon nanotubes is being investigated.

[0011] One method for lengthening carbon nanotubes is to align a plurality of carbon nanotubes in the longitudinal direction and collect them to form an assembled wire.

[0012] As one such method, a method is being considered in which a plurality of unoriented CNTs is mixed with a dispersant (such as a surfactant or polymer) and injection molded into a fiber shape to obtain a carbon nanotube assembly wire (hereinafter, also referred to as a CNT assembly wire) (Non-Patent Document 1: Agnieszka Lekawa-Raus et al. “Electrical Properties of Carbon Nanotube Based Fibers and Their Future Use in Electrical Wiring”, Advanced Functional Materials, Vol. 24, pp3661-3682 (2014). DOI: 10.1002 / adfm.201303716).

[0013] An object of the present disclosure is to provide a long CNT-assembled wire and a carbon nanotube-assembled wire bundle (hereinafter also referred to as a CNT-assembled wire bundle) obtained by collecting CNTs while aligning them in the longitudinal direction.

[0014] Another object of the present disclosure is to provide a carbon nanotube structure (hereinafter also referred to as a CNT structure) that can be used in the above-mentioned CNT-assembled wire and CNT-assembled wire bundle. [Effects of this disclosure]

[0015] According to the above embodiment, it is possible to provide a long CNT aggregate wire and a long CNT aggregate wire bundle by collecting CNTs while aligning them in the longitudinal direction.

[0016] [Description of the embodiments of the present disclosure] First, the embodiments of the present disclosure will be listed and described.

[0017] (1) A carbon nanotube assembly wire according to one embodiment of the present disclosure includes: A carbon nanotube assembly wire including a plurality of carbon nanotubes, The carbon nanotubes are aligned with a degree of orientation of 0.9 or more and 1 or less in the carbon nanotube assembly wire.

[0018] According to the above embodiment, it is possible to provide a long CNT assembled wire by collecting CNTs while aligning them in the longitudinal direction.

[0019] (2) the carbon nanotube assembly wire contains at least one metal element selected from the group consisting of iron, nickel, cobalt, molybdenum, gold, silver, copper, yttrium, chromium, palladium, platinum, and tungsten; The metal elements are preferably dispersed in the longitudinal direction of the carbon nanotube assembly wire.

[0020] This allows the CNT assembled wire to maintain the electrical conductivity that CNTs inherently possess.

[0021] (3) the carbon nanotube assembly wire has catalyst particles; The catalyst particles preferably have an average particle size of 0.6 nm or more and less than 30 nm.

[0022] This allows the CNT assembled wire to maintain the electrical conductivity that CNTs inherently possess.

[0023] (4) The catalyst particles preferably contain iron, which allows for mass production of long CNT aggregated wires.

[0024] (5) the carbon nanotube assembly wire contains elemental sulfur; The sulfur element is preferably dispersed in the longitudinal direction of the carbon nanotube assembly wire.

[0025] This allows the CNT assembled wire to maintain the electrical conductivity and mechanical properties inherent to CNTs.

[0026] (6) A carbon nanotube assembly wire bundle according to another embodiment of the present disclosure, A carbon nanotube assembly wire bundle including a plurality of carbon nanotube assembly wires according to any one of (1) to (5), In the carbon nanotube assembly wire, the carbon nanotubes are aligned with an orientation degree of 0.9 or more and 1 or less, The carbon nanotube assembly wire bundle includes an orientation region in which the carbon nanotube assembly wires are oriented with an orientation degree of 0.8 or more and 1 or less.

[0027] According to the above embodiment, it is possible to provide a carbon nanotube assembly wire bundle in which a plurality of carbon nanotube assembly wires, each of which is made by aligning and assembling CNTs in the longitudinal direction and forming an elongated length, are assembled and aligned in the longitudinal direction.

[0028] (7) The carbon nanotube assembly wire bundle preferably includes the oriented region and an amorphous region in which the degree of orientation of the carbon nanotube assembly wire is equal to or greater than 0 and less than 0.8. By controlling the size of the amorphous region, it is possible to arbitrarily add a buffering effect against bending and twisting in addition to the inherent structural flexibility of the carbon nanotube assembly wire.

[0029] (8) In at least a part of the alignment region, the minimum distance between adjacent carbon nanotube aggregate wires is preferably 10 times or more the average diameter of the carbon nanotube aggregate wires. This makes it possible to arbitrarily add a buffering effect against bending and twisting without adjacent carbon nanotube aggregate wires being bonded to each other.

[0030] (9) The carbon nanotube wire bundle preferably has an elongation at break of 0.1% or more and a breaking strength of 1 GPa or more, so that the CTN wire bundle can have excellent mechanical strength.

[0031] (10) The carbon nanotube wire bundle preferably has a Young's modulus of 10 GPa or more, which allows the CTN wire bundle to have excellent mechanical strength.

[0032] (11) The carbon nanotube assembly wire bundle preferably contains 10 mass % or less in total of at least one first element selected from the group consisting of iron, sulfur, nickel, cobalt, molybdenum, gold, silver, copper, yttrium, chromium, palladium, platinum, and tungsten.

[0033] This allows the CNT assembly wire bundle to have excellent mechanical strength.

[0034] (12) A carbon nanotube structure according to another embodiment of the present disclosure, Carbon nanotubes, and catalyst particles attached to both ends of the carbon nanotubes; The catalyst particles are carbon nanotube structures having a particle diameter of 0.6 nm or more and less than 30 nm.

[0035] The carbon nanotube structure can be suitably used for the above-mentioned CNT assembled wire and CNT assembled wire bundle.

[0036] (13) The catalyst particles preferably contain iron, which makes it possible to mass-produce long CNT aggregate wires using the CNT structure.

[0037] [Details of the embodiment of the present invention] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific examples of a carbon nanotube assembly wire, a carbon nanotube assembly wire bundle, and a carbon nanotube structure according to an embodiment of the present disclosure will be described with reference to the drawings.

[0038] In the drawings of this disclosure, the same reference numerals represent the same or corresponding parts. In addition, the dimensional relationships such as length, width, thickness, depth, etc. are appropriately changed for clarity and simplification of the drawings, and do not necessarily represent the actual dimensional relationships.

[0039] In this specification, the expression in the form "A to B" means the upper and lower limits of a range (i.e., greater than or equal to A and less than or equal to B), and when no unit is specified for A and only a unit is specified for B, the units of A and B are the same. Furthermore, when the upper limit of the range is C, it means that the upper limit of the range is less than or equal to C, and when the lower limit of the range is D, it means that the lower limit of the range is greater than or equal to D.

[0040] [Embodiment 1: Carbon nanotube assembly wire] <Carbon nanotube assembly wire> Fig. 1 is a diagram illustrating a typical configuration example of a carbon nanotube aggregate wire (hereinafter, also referred to as a CNT aggregate wire) according to one embodiment of the present disclosure. As shown in Fig. 1, a carbon nanotube aggregate wire 1 according to this embodiment includes a plurality of carbon nanotubes 2. In the CNT aggregate wire, the plurality of carbon nanotubes 2 are aligned with an orientation degree of 0.9 or more and 1.0 or less.

[0041] (degree of orientation) The method for calculating the degree of orientation of CNTs in this specification will be described with reference to Figures 2 to 5. In this specification, the degree of orientation of CNTs is a value calculated by the following procedures (a1) to (a6). As far as the applicant has measured, it has been confirmed that there is almost no variation in the measurement results when the CNT orientation measurement described below is performed multiple times by changing the selected location of the measurement field of view (size: 10 nm x 10 nm) as long as the measurement is performed on the same sample.

[0042] (a1) Image of CNT assembly The CNT assembly line is photographed under the following conditions using the following equipment.

[0043] Transmission electron microscope (TEM): JEOL "JEM2100" (product name) Imaging conditions: magnification 50,000 to 1.2 million times, accelerating voltage 60 kV to 200 kV.

[0044] FIG. 2 shows an example of a TEM image of the CNT aggregate wire according to this embodiment.

[0045] (a2) Binarization of captured images The image captured in (a1) above is subjected to binarization processing using the following image processing program and following the procedure below.

[0046] Image processing program: Non-destructive paper surface fiber orientation analysis program "FiberOri8single03" (http: / / www.enomae.com / FiberOri / index.htm) Process steps: 1. Histogram average brightness correction 2. Background Removal 3. Binarization by a single threshold 4. Luminance inversion.

[0047] Figure 3 shows the binarized image of the TEM image in Figure 2. (a3) Fourier transform of the binarized image The image obtained in (a2) above is subjected to Fourier transformation using the same image processing program as above (non-destructive paper surface fiber orientation analysis program “FiberOri8single03” (http: / / www.enomae.com / FiberOri / index.htm).

[0048] FIG. 4 shows an image obtained by Fourier transforming the binarized image in FIG. (a4) Calculation of orientation angle and orientation strength In the Fourier transform image, the positive X-axis direction is set as 0°, and the average amplitude is calculated with respect to the counterclockwise angle (θ°).

[0049] FIG. 5 shows a graph illustrating the relationship between the orientation angle and the orientation strength obtained from the Fourier transform image of FIG.

[0050] (a5) Measurement of half-width Based on the graph in Figure 5, the full width at half maximum (FWHM) Measure the maximum.

[0051] (a6) Calculation of the degree of orientation Based on the full width at half maximum, the degree of orientation is calculated according to the following formula (1).

[0052] Orientation degree=(180°-full width at half maximum) / 180° (1) An orientation degree of 0 means completely non-oriented, and an orientation degree of 1 means completely oriented.

[0053] In the carbon nanotube assembly wire according to this embodiment, the plurality of carbon nanotubes are aligned with an orientation degree of 0.9 or more and 1 or less. This means that the orientation of the plurality of CNTs is high in the CNT assembly wire according to this embodiment. As a result, the CNT assembly wire according to this embodiment can be made long while maintaining the electrical conductivity and mechanical strength properties of the CNTs.

[0054] If the degree of orientation of the CNTs in the CNT assembly wire is less than 0.9, the electrical conductivity and mechanical strength tend to decrease. The lower limit of the degree of orientation is preferably 0.93, more preferably 0.94, and even more preferably 0.95. The upper limit of the degree of orientation is preferably 0.99, and more preferably 1. The degree of orientation of the CNTs is 0.9 or more and 1 or less, preferably 0.93 or more and 1 or less, more preferably 0.94 or more and 1 or less, and even more preferably 0.95 or more and 1 or less. In addition, the degree of orientation of the CNTs is preferably 0.93 or more and 0.99 or less, more preferably 0.94 or more and 0.99 or less, and even more preferably 0.95 or more and 0.99 or less.

[0055] (shape) The carbon nanotube assembly wire has a thread-like shape in which a plurality of carbon nanotubes are assembled and aligned in the longitudinal direction.

[0056] The length of the carbon nanotube assembly wire is not particularly limited and can be adjusted appropriately depending on the application. The length of the CNT assembly wire is, for example, preferably 100 μm or more, more preferably 1000 μm or more, and even more preferably 10 cm or more. The upper limit of the length of the CNT assembly wire is not particularly limited, but from the viewpoint of production, it is preferably 1 m or less. The length of the CNT assembly wire can be measured by observing with a scanning electron microscope, an optical microscope, or visually.

[0057] The diameter of the carbon nanotube aggregate wire is not particularly limited and can be adjusted appropriately depending on the application. The diameter of the CNT aggregate wire is, for example, preferably 0.1 μm or more, more preferably 1 μm or more. The upper limit of the diameter of the CNT aggregate wire is not particularly limited, but from the viewpoint of production, it is preferably 100 μm or less. In this embodiment, the diameter of the CNT aggregate wire is smaller than the length of the CNT aggregate wire. That is, the length direction of the CNT aggregate wire corresponds to the longitudinal direction.

[0058] In this specification, the diameter of a carbon nanotube aggregate wire means the average outer diameter of a single CNT aggregate wire. The average outer diameter of a single CNT aggregate wire is obtained by observing a cross section of a single CNT aggregate wire at any two points with a transmission electron microscope or a scanning electron microscope, measuring the outer diameter, which is the distance between the two most distant points on the circumference of the CNT aggregate wire at the cross section, and calculating the average value of the obtained outer diameters.

[0059] (Catalyst-derived elements) The carbon nanotube assembly wire preferably contains at least one metal element selected from the group consisting of iron, nickel, cobalt, molybdenum, gold, silver, copper, yttrium, chromium, palladium, platinum, and tungsten, and the metal element is preferably dispersed in the longitudinal direction of the carbon nanotube assembly wire. Here, "the metal element is dispersed in the longitudinal direction of the CNT assembly wire" means that the metal element is not unevenly distributed in the longitudinal direction of the CNT assembly wire.

[0060] These metal elements are derived from the catalysts (such as ferrocene (Fe(C5H5)2), nickelocene (Ni(C5H5)2), cobaltocene (Co(C5H5)2, nanoparticles made of molybdenum, gold, silver, copper, yttrium, chromium, palladium, platinum, and tungsten) used in the production of the CNT assembled wire. In the CNT assembled wire according to this embodiment, these metal elements are dispersed in the longitudinal direction of the CNT assembled wire, and therefore the metal elements do not affect the electrical conductivity properties of the CNTs. Therefore, the CNT assembled wire can be elongated while maintaining the electrical conductivity inherent to the CNTs.

[0061] The types and contents of metal elements contained in the CNT assembly wire can be confirmed and measured by energy dispersive X-ray spectrometry (EDX). The total content of metal elements in the CNT assembly wire is preferably 0.1% to 50%, more preferably 1% to 40%, and even more preferably 5% to 20%, based on the number of atoms.

[0062] The fact that the metal elements contained in the CNT assembly wire are dispersed in the longitudinal direction of the carbon nanotube assembly wire can be confirmed by EDX, which can be measured simultaneously with electron microscopes such as SEM and TEM, and electron energy loss spectrometry (EELS).

[0063] The carbon nanotube assembly wire has catalyst particles, and the catalyst particles preferably have an average particle diameter of 0.6 nm or more and less than 30 nm. The catalyst particles are derived from the catalyst (such as nanoparticles made of ferrocene (Fe(C5H5)2), iron oxide powder (Fe2O3), molybdenum, gold, silver, copper, yttrium, chromium, palladium, platinum, and tungsten) used in the production of the CNT assembly wire. In the CNT assembly wire according to this embodiment, the average particle diameter of the catalyst particles is small, less than 30 nm, and the catalyst particles are not coarsened, so that the catalyst particles do not affect the electrical conductivity characteristics of the CNTs. Therefore, the CNT assembly wire can be elongated while maintaining the electrical conductivity inherent to the CNTs.

[0064] Here, the "average particle size" of the catalyst particles means the median size (d50) in the volumetric particle size distribution (volume distribution), and means the average particle size of all catalyst particles contained in the CNT aggregate wire. In this specification, the "average particle size" may be simply referred to as the "particle size".

[0065] The particle size of each particle for calculating the particle size (volume average particle size) of the catalyst particles contained in the CNT aggregate wire can be measured by the following method. First, an arbitrary region (measurement field of view 0.5 μm × 0.5 μm) of the carbon nanotube aggregate wire is observed at a magnification of 100,000 to 500,000 times using a transmission electron microscope (TEM). Next, in the TEM image, the outer diameter, which is the distance between the two most distant points on the circumference of each catalyst particle, is measured, and the average value of the obtained outer diameters is calculated.

[0066] The catalyst particles contained in the CNT assembly wire can contain at least one metal element selected from the group consisting of iron, nickel, cobalt, molybdenum, gold, silver, copper, yttrium, chromium, palladium, platinum, and tungsten. Here, the catalyst particles containing a metal element refers to both cases where the catalyst particles contain other elements (e.g., sulfur, oxygen, etc.) in addition to the metal element, and cases where the catalyst particles are composed only of the metal element.

[0067] The catalyst particles contained in the CNT assembly wire preferably contain iron. In this case, the catalyst particles can be, for example, iron particles consisting of only iron, or iron sulfide (FeS, Fe2S), or iron oxide (Fe2O3, Fe3O4). The catalyst particles are more preferably iron particles consisting of iron. Using iron as a catalyst is suitable from the viewpoint of mass production of CNTs. Therefore, when the catalyst particles contain iron, it is possible to mass-produce long CNT assembly wires.

[0068] The composition and content of the catalyst particles contained in the CNT assembly wire can be confirmed by energy dispersive X-ray spectrometry (EDX). The total content of the catalyst particles in the CNT assembly wire is preferably 0.01% to 50% by mass, more preferably 0.5% to 40%, and even more preferably 0.1% to 20%.

[0069] The carbon nanotube aggregate wire preferably contains elemental sulfur, and the elemental sulfur is preferably dispersed in the longitudinal direction of the carbon nanotube aggregate wire. Here, "elemental sulfur is dispersed in the longitudinal direction of the CNT aggregate wire" means that the elemental sulfur is not unevenly distributed in the longitudinal direction of the CNT aggregate wire.

[0070] The sulfur element is derived from the auxiliary catalyst (CS2) used in the production of the CNT aggregate wire. In the CNT aggregate wire according to this embodiment, the sulfur element is dispersed in the longitudinal direction of the CNT aggregate wire, so that the sulfur element does not affect the properties of the CNT such as electrical conductivity and mechanical strength, and the CNT aggregate wire can be made long while maintaining these properties.

[0071] The fact that the CNT aggregate wire contains elemental sulfur and the amount of elemental sulfur in the CNT aggregate wire can be confirmed and measured by EDX, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The amount of elemental sulfur in the CNT aggregate wire is preferably 0.1% to 20%, more preferably 1% to 15%, and even more preferably 2% to 10%, based on the number of atoms.

[0072] The fact that the sulfur elements contained in the CNT assembly wire are dispersed in the longitudinal direction of the carbon nanotube assembly wire can be confirmed by EDX or EELS, which can be used for simultaneous measurement with an electron microscope such as SEM or TEM.

[0073] <Carbon nanotubes> (Shape of carbon nanotubes) As the carbon nanotube, CNTs with a known structure can be used, such as single-walled carbon nanotubes in which only one carbon layer (graphene) is cylindrical, double-walled carbon nanotubes or multi-walled carbon nanotubes in which multiple carbon layers are stacked in a cylindrical shape, and cup-stacked nanotubes in which graphene is stacked in the shape of a paper cup with a bottom.

[0074] The shape of the carbon nanotube is not particularly limited, and either one with a closed end or one with an open end can be used. As shown in Fig. 6, catalyst particles P used in producing the carbon nanotube may be attached to one or both ends of the tube part T of the carbon nanotube 2. A cone part C made of conical graphene may be formed on one or both ends of the tube part T of the carbon nanotube 2.

[0075] The length of the carbon nanotube can be appropriately selected depending on the application. The length of the carbon nanotube is, for example, preferably 10 μm or more, more preferably 100 μm or more. In particular, a length of 100 μm or more is suitable from the viewpoint of producing a CNT assembly wire. The upper limit of the length of the carbon nanotube is not particularly limited, but from the viewpoint of production, it is preferably 600 mm or less. The length of the CNT can be measured by observing with a scanning electron microscope.

[0076] The diameter of the carbon nanotube is preferably 0.6 nm to 20 nm, more preferably 1 nm to 10 nm, and particularly preferably 1 nm to 10 nm, from the viewpoint of heat resistance under oxidizing conditions.

[0077] In this specification, the diameter of a carbon nanotube means the average outer diameter of one CNT. The average outer diameter of a CNT is obtained by directly observing the cross section of a CNT at any two points using a transmission electron microscope, measuring the outer diameter, which is the distance between the two most distant points on the circumference of the CNT, at the cross section, and calculating the average of the obtained outer diameters. When a CNT includes a cone portion at one or both ends, the diameter is measured at a location excluding the cone portion.

[0078] (D / G ratio) The carbon nanotubes preferably have a D / G ratio, which is the ratio of the peak intensity of the G band to the peak intensity of the D band, of 0.1 or less in Raman spectroscopy at a wavelength of 532 nm.

[0079] The G band is a band with a Raman shift of 1590 cm in the Raman spectrum obtained by Raman spectroscopy. -1 The D band is a peak derived from CNTs seen around the Raman shift of 1350 cm in the Raman spectrum obtained by Raman spectroscopy. -1 These peaks are due to amorphous carbon, graphite, and CNT defects seen near the D / G ratio. Therefore, the smaller the D / G ratio, the higher the crystallinity of the carbon nanotube and the smaller the amount of amorphous carbon and graphite with defects contained in the carbon nanotube.

[0080] When the D / G ratio of CNT is 0.1 or less, there are few defects in amorphous carbon or graphite, and the crystallinity is high. Therefore, the CNT can have high tensile strength and high electrical conductivity. When the D / G ratio of CNT exceeds 0.1, the CNT may not have sufficient tensile strength and high electrical conductivity. The D / G ratio is preferably 0.1 or less, more preferably 0.01 or less. The lower limit of the D / G ratio is not particularly limited, but can be, for example, 0 or more.

[0081] In this specification, the D / G ratio of the carbon nanotubes in the carbon nanotube assembly wire is a value measured by the following method.

[0082] A Raman spectroscopic analysis is performed on the carbon nanotube assembly wire under the following conditions to obtain a Raman spectrum (hereinafter, also referred to as the Raman spectrum of the CNT assembly wire). In the Raman spectrum of the CNT assembly wire, the D / G ratio is calculated from the peak intensity of the G band and the peak intensity of the D band. The D / G ratio of the CNT assembly wire is regarded as the D / G ratio of the carbon nanotubes in the carbon nanotube assembly wire. Raman spectroscopic analysis conditions Wavelength: 532nm Laser power: 17mW Exposure time: 1 second Average number of times: 3 Objective lens magnification: 50x The reason why the D / G ratio of the CNTs in the CNT assembled wire according to this embodiment is considered to be the same as the D / G ratio of the CNT assembled wire is as follows.

[0083] The inventors performed Raman spectroscopy on a plurality of carbon nanotubes before they were assembled into a fiber under the same conditions as described above to obtain Raman spectra (hereinafter, also referred to as CNT Raman spectra). In each of the obtained CNT Raman spectra, the D / G ratio was calculated from the peak intensity of the G band and the peak intensity of the D band.

[0084] Next, the carbon nanotubes were assembled into a CNT assembled wire to prepare the wire. The CNT assembled wire was subjected to Raman spectroscopy under the above-mentioned conditions to obtain a Raman spectrum (hereinafter, also referred to as the CNT assembled wire Raman spectrum). In the CNT assembled wire Raman spectrum, the D / G ratio was calculated from the peak intensity of the G band and the peak intensity of the D band.

[0085] It was confirmed that the average value of the D / G ratio data of the multiple carbon nanotubes before being assembled into an assembled wire, calculated above, was almost identical to the D / G ratio value of the CNT assembled wire. This indicates that the D / G ratio of the carbon nanotubes before being assembled into an assembled wire is maintained in the CNTs in the CNT assembled wire. Therefore, in this specification, the D / G ratio of the carbon nanotubes in the CNT assembled wire can be regarded as being the same as the D / G ratio of the CNTs before being assembled into an assembled wire.

[0086] [Embodiment 2: Carbon nanotube assembly wire bundle] 7 is a diagram illustrating a representative configuration example of a carbon nanotube aggregate wire bundle according to an embodiment of the present disclosure. As shown in Fig. 7, a carbon nanotube aggregate wire bundle (hereinafter also referred to as a CNT aggregate wire bundle) 3 according to this embodiment includes a plurality of carbon nanotube aggregate wires 1. In the carbon nanotube aggregate wire 1, the carbon nanotubes 2 are aligned with an orientation degree of 0.9 to 1, and the carbon nanotube aggregate wire bundle 3 includes an alignment region in which the carbon nanotube aggregate wires 1 are aligned with an orientation degree of 0.8 to 1.

[0087] (Structure of carbon nanotube wire bundle) The CNT assembled wire of the first embodiment can be used as the carbon nanotube assembled wire 1 constituting the carbon nanotube assembled wire bundle 3. In addition, the carbon nanotubes 2 constituting the CNT assembled wire 1 can be the same as the carbon nanotubes described in the first embodiment.

[0088] (Orientation degree) The degree of orientation of CNTs in a carbon nanotube aggregate wire is a value calculated by a method similar to the method for calculating the degree of orientation of carbon nanotubes in a carbon nanotube aggregate wire described in the first embodiment, and therefore the description thereof will not be repeated.

[0089] The orientation degree of the CNT-aggregated wire in the carbon nanotube aggregate wire bundle is a value calculated basically by the same procedures as (a1) to (a6) described in the method for calculating the orientation degree in embodiment 1. The difference is that in procedure (a1), the CNT-aggregated wire bundle is imaged under the following conditions using the following equipment.

[0090] Scanning Electron Microscope (SEM): Technex Kobo's "Cry-10" (product name) Imaging conditions: Magnification 40x to 100,000x, accelerating voltage 1kV to 17k Measurement field of view: 30μm×30μm

[0091] FIG. 8 shows an SEM image of an example of the CNT-aggregated wire bundle according to this embodiment taken under the above conditions.

[0092] FIG. 9 shows an image obtained by binarizing the SEM image of FIG. 8 in the above step (a2). FIG. 10 shows an image obtained by Fourier transforming the binarized image of FIG. 9 in the above step (a3).

[0093] FIG. 11 shows a graph illustrating the relationship between the orientation angle and the orientation strength obtained from the Fourier transform image of FIG. 10 in the above step (a4).

[0094] In the above step (a5), the full width at half maximum is measured based on the graph in FIG. In the above step (a6), the degree of orientation is calculated based on the above full width at half maximum by the following formula (1).

[0095] Orientation degree=(180°-full width at half maximum) / 180° (1) An orientation degree of 0 means completely non-oriented, and an orientation degree of 1 means completely oriented.

[0096] The above measurement is performed in 10 or more measurement visual fields selected arbitrarily. When the degree of orientation of the carbon nanotube assembly wire in the carbon nanotube assembly wire bundle is 0.8 to 1 in one or more of all the measurement visual fields, the carbon nanotube assembly wire bundle is determined to include an orientation region in which the carbon nanotube assembly wire is oriented with a degree of orientation of 0.8 to 1.

[0097] In the carbon nanotube assembly wire bundle according to this embodiment, the carbon nanotubes are oriented with an orientation degree of 0.9 to 1, and the carbon nanotube assembly wire bundle includes an orientation region in which the carbon nanotube assembly wire is oriented with an orientation degree of 0.8 to 1. This means that the CNTs and the CNT assembly wire are highly oriented in the CNT assembly wire bundle according to this embodiment. As a result, the CNT assembly wire bundle according to this embodiment can be made long while maintaining the electrical conductivity and mechanical strength properties of the CNTs.

[0098] If the degree of orientation of the CNTs in the CNT assembly wire is less than 0.9, the electrical conductivity and mechanical strength tend to decrease. The lower limit of the degree of orientation is 0.9, preferably 0.93, more preferably 0.94, and even more preferably 0.95. The upper limit of the degree of orientation is preferably 0.99, and more preferably 1.

[0099] If the orientation degree of the CNT aggregate wire in the CNT aggregate wire bundle is less than 0.8, the electrical conductivity and mechanical strength tend to decrease. The lower limit of the orientation degree is 0.8, preferably 0.83, and more preferably 0.85. The upper limit of the orientation degree is preferably 0.95, and more preferably 1.

[0100] (shape) The shape of the carbon nanotube assembly wire bundle is a string shape formed by assembling a plurality of carbon nanotube assembly wires aligned in their longitudinal direction. It can be confirmed that the CNT assembly wire bundle is a string shape formed by assembling a plurality of carbon nanotube assembly wires aligned in their longitudinal direction by observing with an optical microscope or a scanning electron microscope.

[0101] The length of the carbon nanotube assembly wire bundle is not particularly limited and can be adjusted appropriately depending on the application. The length of the CNT assembly wire bundle is, for example, preferably 100 μm or more, more preferably 1000 μm or more, and even more preferably 10 cm or more. The upper limit of the length of the CNT assembly wire bundle is not particularly limited, but from the viewpoint of production, it is preferably 1 m or less. The length of the CNT assembly wire bundle can be measured by observing with an optical microscope or visually.

[0102] The diameter of the carbon nanotube assembly wire bundle is not particularly limited and can be adjusted appropriately depending on the application. The diameter of the CNT assembly wire bundle is, for example, preferably 1 μm or more, more preferably 10 μm or more. The upper limit of the diameter of the CNT assembly wire bundle is not particularly limited, but from the viewpoint of production, it is preferably 1000 μm or less. In this embodiment, the diameter of the CNT assembly wire bundle is smaller than the length of the CNT assembly wire bundle.

[0103] In this specification, the diameter of a carbon nanotube aggregate wire bundle means the average outer diameter of one CNT aggregate wire bundle. The average outer diameter of one CNT aggregate wire bundle is obtained by observing a cross section of one CNT aggregate wire bundle at any two points with an optical microscope, measuring the outer diameter, which is the distance between the two most distant points on the circumference of the CNT aggregate wire bundle in the cross section, and calculating the average value of the obtained outer diameters.

[0104] (Oriented region and amorphous region) FIG. 12 is an SEM image of a carbon nanotube assembly wire bundle according to an embodiment of the present disclosure. As shown in FIG. 12, the carbon nanotube assembly wire bundle can include an orientation region 35 and an irregular region 36 in which the orientation degree of the carbon nanotube assembly wire is 0 or more and less than 0.8. In this specification, the orientation region means a region in the CNT assembly wire bundle in which the orientation degree of the CNT assembly wire is 0.8 or more and 1.0 or less. On the other hand, the irregular region means a region in the CNT assembly wire bundle in which the orientation degree of the CNT assembly wire is 0 or more and less than 0.8. By including an orientation region and an irregular region in the CNT assembly wire bundle, adjacent CNT assembly wires do not adhere to each other, and a buffer effect against bending and twisting can be added arbitrarily.

[0105] The ratio of the oriented region in the carbon nanotube assembly wire bundle is preferably 50% by volume or more and less than 100% by volume. This allows the CNT assembly wires in the carbon nanotube assembly wire bundle to have a sufficient degree of orientation. The ratio of the oriented region in the CNT assembly wire bundle is more preferably 60% by volume or more and 99% by volume or less, and further preferably 70% by volume or more and 99% by volume or less.

[0106] The ratio of the shapeless region in the carbon nanotube assembly wire bundle is preferably greater than 0 volume % and less than or equal to 50 volume %. This allows the CNT assembly wires in the carbon nanotube assembly wire bundle to have a sufficient degree of orientation. The ratio of the shapeless region in the CNT assembly wire bundle is more preferably 1 volume % or more and 40 volume % or less, and further preferably 1 volume % or more and 30 volume % or less.

[0107] The ratio of the oriented region and the shapeless region in the carbon nanotube assembly wire bundle is a value calculated by the following procedures (b1) to (b3).

[0108] (b1) Setting the measurement field of view On the surface of the carbon nanotube wire bundle, ten or more rectangular measurement fields of 1 mm x 1 mm are randomly selected.

[0109] (b2) Measurement of the degree of orientation For each of the 10 or more measurement visual fields set in (b1) above, the orientation degree of the CNT aggregate wires in the CNT aggregate wire bundle is calculated using the same procedure as in the measurement of the orientation degree of the CNT aggregate wires in the CNT aggregate wire bundle described above.

[0110] (b3) Calculation of percentages The percentage of oriented regions in the CNT-assembled wire bundle can be obtained by calculating the percentage of the number of measurement fields in which the degree of orientation is 0.8 or more and 1.0 or less (oriented regions) out of all measurement fields. Also, the percentage of amorphous regions in the CNT-assembled wire bundle can be obtained by calculating the percentage of the number of measurement fields in which the degree of orientation is 0 or more and less than 0.8 (irregular regions) out of all measurement fields.

[0111] (Distance between carbon nanotube bundles) In at least a part of the orientation region of the CNT-assembled wire bundle of this embodiment, the minimum distance between adjacent carbon nanotube-assembled wires is preferably 10 times or more the average diameter of the carbon nanotube-assembled wires. This allows the adjacent carbon nanotube-assembled wires to be prevented from adhering to each other, and allows a cushioning effect against bending and twisting to be added as desired.

[0112] A method for measuring the distance between adjacent CNT-aggregated wires in an orientation region of a CNT-aggregated wire bundle in this specification will be described with reference to Fig. 13. Fig. 13 is a diagram showing a schematic diagram of an example of an orientation region of a CNT-aggregated wire bundle according to an embodiment of the present disclosure. In this specification, the distance between CNT-aggregated wires can be confirmed by the following procedures (c1) and (c2).

[0113] (c1) Setting the measurement field of view Among the orientation regions observed in (b1) to (b3) above, one is arbitrarily selected, and a square measurement field of view of 0.1 mm×0.1 mm is set within the orientation region. When setting the measurement field of view, at least one side of the square that is the outer frame of the measurement field of view is set to be approximately parallel to at least one of the carbon nanotube aggregate wires. For example, in FIG. 13, the carbon nanotube aggregate wire 1a and one side W of the square are parallel. Here, approximately parallel means that the angle between a specific carbon nanotube aggregate wire and one side of the rectangle is 5° or less.

[0114] (c2) Measurement of the distance between adjacent carbon nanotube bundles In the measurement field set in the above (c1), the distance between adjacent carbon nanotube aggregate wires is measured by observing with a scanning electron microscope. Here, the distance between adjacent carbon nanotube aggregate wires means the distance between a specific carbon nanotube aggregate wire and the carbon nanotube aggregate wire that is closest to the specific carbon nanotube aggregate wire.

[0115] 13, the CNT-aggregated wire adjacent to the carbon nanotube aggregate wire 1a is the carbon nanotube aggregate wire 1b, and the minimum value of the distance between the CNT-aggregated wire 1a and the CNT-aggregated wire 1b is d1. The CNT-aggregated wire adjacent to the carbon nanotube aggregate wire 1c is the carbon nanotube aggregate wire 1b, and the minimum value of the distance between the CNT-aggregated wire 1c and the CNT-aggregated wire 1b is d2. The CNT-aggregated wire adjacent to the carbon nanotube aggregate wire 1d is the carbon nanotube aggregate wire 1c, and the minimum value of the distance between the CNT-aggregated wire 1d and the CNT-aggregated wire 1c is d3.

[0116] (Comparison of the distance between CNT aggregates and the average diameter of the CNT aggregates) The lengths of d1, d2, and d3 are measured, and the minimum value among them is determined. By comparing the minimum value with the average diameter of the carbon nanotube aggregate wires, it is possible to confirm whether the minimum value of the distance between adjacent carbon nanotube aggregate wires in at least a part of the orientation region of the CNT aggregate wire bundle is 10 times or more the average diameter of the carbon nanotube aggregate wires. Here, the average diameter of the carbon nanotube aggregate wires means the average diameter of the carbon nanotube aggregate wires present in the measurement field of view set in (c1) above.

[0117] In this specification, the diameter of the carbon nanotube aggregate wire means the average outer diameter of one CNT aggregate wire. The average outer diameter of each of the CNT aggregate wires 1a, 1b, 1c, and 1d is obtained by directly observing a cross section of each of the CNT aggregate wires at two arbitrary points with a transmission electron microscope or a scanning electron microscope, measuring the outer diameter, which is the distance between the two most distant points on the circumference of the CNT aggregate wire, at the cross section, and calculating the average value of the obtained outer diameters. The average diameter of the multiple carbon nanotube aggregate wires in the measurement field of view is calculated from the average outer diameter of each of the CNT aggregate wires 1a, 1b, 1c, and 1d.

[0118] The minimum distance between adjacent carbon nanotube aggregate wires is preferably 10 to 50 times the average diameter of the carbon nanotube aggregate wires, more preferably 15 to 40 times, and even more preferably 20 to 30 times. If the minimum distance between adjacent carbon nanotube aggregate wires exceeds 50 times the average diameter of the carbon nanotube aggregate wires, there will be many voids, which will easily allow foreign matter to enter, and when an external force is applied, stress will be concentrated near the foreign matter, reducing the cushioning effect and possibly causing breakage.

[0119] (Angle between carbon nanotube bundles) In at least a part of the orientation region of the CNT-assembled wire bundle of this embodiment, the maximum angle between adjacent carbon nanotube-assembled wires is preferably 10° or less. This allows the adjacent carbon nanotube-assembled wires to be prevented from adhering to each other, and allows a buffering effect against bending and twisting to be added as desired.

[0120] In this specification, the angle between adjacent carbon nanotube aggregate wires in at least a part of the orientation region of the CNT aggregate wire bundle can be confirmed by the following procedures (d1) and (d2).

[0121] (d1) Determination of the measurement field Determine a 0.1 mm x 0.1 mm square measurement field of view in the same manner as in (c1) above.

[0122] (d2) Measurement of the angle between adjacent carbon nanotube bundles In the field of view set in (d1) above, the angle between adjacent carbon nanotube aggregate wires is measured. Here, the angle between adjacent carbon nanotube aggregate wires means the angle between a specific carbon nanotube aggregate wire and the carbon nanotube aggregate wire that is closest to the specific carbon nanotube aggregate wire.

[0123] For example, the CNT-aggregated wire adjacent to the carbon nanotube aggregate wire 1a shown in FIG. 13 is the carbon nanotube aggregate wire 1b, and the angle between the CNT-aggregated wire 1a and the CNT-aggregated wire 1b (same as the angle between the parallel line 1a' of the CNT-aggregated wire 1a and the CNT-aggregated wire 1b) is α1°. The CNT-aggregated wire adjacent to the carbon nanotube aggregate wire 1c is the carbon nanotube aggregate wire 1b, and the angle between the CNT-aggregated wire 1c and the CNT-aggregated wire 1b (same as the angle between the parallel line 1c' of the CNT-aggregated wire 1c and the CNT-aggregated wire 1b) is α2°. The CNT-aggregated wire adjacent to the carbon nanotube aggregate wire 1c is the carbon nanotube aggregate wire 1d, and the CNT-aggregated wire 1c and the CNT-aggregated wire 1d are parallel to each other, and the angle is 0°.

[0124] When the maximum value of the above angles α1° and α2° is 10° or less, it is determined that the angle between adjacent carbon nanotube aggregate wires is 10° or less in at least a part of the orientation region of the CNT aggregate wire bundle.

[0125] The angle between adjacent carbon nanotube aggregate lines is preferably 10° or less, more preferably 9° or less, further preferably 5° or less, and most preferably 0°.

[0126] (Catalyst-derived elements) The carbon nanotube assembly wire bundle preferably contains at least one metal element selected from the group consisting of iron, nickel, cobalt, molybdenum, gold, silver, copper, yttrium, chromium, palladium, platinum, and tungsten, and the metal element is preferably dispersed in the longitudinal direction of the carbon nanotube assembly wire bundle. Here, "the metal element is dispersed in the longitudinal direction of the CNT assembly wire bundle" means that the metal element is not unevenly distributed in the longitudinal direction of the CNT assembly wire.

[0127] These metal elements are derived from the catalysts (ferrocene (Fe(C5H5)2), nickelocene (Ni(C5H5)2), cobaltocene (Co(C5H5)2, nanoparticles made of molybdenum, gold, silver, copper, yttrium, chromium, palladium, platinum, and tungsten, etc.) used in manufacturing the CNT-assembled wire bundle. In the CNT-assembled wire bundle according to this embodiment, these metal elements are dispersed in the longitudinal direction of the CNT-assembled wire bundle, so the metal elements do not affect the electrical conductivity properties of the CNTs. Therefore, the CNT-assembled wire bundle can be elongated while maintaining the electrical conductivity inherent to the CNTs.

[0128] The types and contents of metal elements contained in the CNT-assembled wire bundle can be confirmed and measured by energy dispersive X-ray spectrometry (EDX). The total content of metal elements in the CNT-assembled wire bundle is preferably 0.1% to 50% based on the number of atoms, more preferably 1% to 40%, and even more preferably 5% to 20%.

[0129] The fact that the metal elements contained in the CNT assembly wire bundle are dispersed in the longitudinal direction of the carbon nanotube assembly wire bundle can be confirmed by EDX, which can be measured simultaneously with electron microscopes such as SEM and TEM, and electron energy loss spectrometry (EELS).

[0130] The carbon nanotube assembly wire bundle has catalyst particles, and the catalyst particles preferably have an average particle diameter of 0.6 nm or more and less than 30 nm. The catalyst particles are derived from the catalyst (nanoparticles made of ferrocene (Fe(C5H5)2), iron oxide (Fe2O3), molybdenum, gold, silver, copper, yttrium, chromium, palladium, platinum, and tungsten, etc.) used in the production of the CNT assembly wire. In the CNT assembly wire bundle according to this embodiment, the average particle diameter of the catalyst particles is small, less than 30 nm, and the catalyst particles are not coarsened, so that the catalyst particles do not affect the electrical conductivity characteristics of the CNTs. Therefore, the CNT assembly wire bundle can be lengthened while maintaining the electrical conductivity inherent to the CNTs.

[0131] Here, the definition of the "average particle size" of the catalyst particles is the same as the definition of the "average particle size" of the catalyst particles described in the first embodiment above, and therefore the description thereof will not be repeated.

[0132] The particle diameter of each particle for calculating the particle diameter (volume average particle diameter) of the catalyst particles contained in the CNT assembly wire bundle can be measured by the following method. First, an arbitrary region (measurement field of view 0.5 μm × 0.5 μm) of the carbon nanotube assembly wire bundle is observed at a magnification of 100,000 to 500,000 times using a transmission electron microscope (TEM). Next, in the TEM image, the outer diameter, which is the distance between the two most distant points on the circumference of each catalyst particle, is measured, and the average value of the obtained outer diameters is calculated.

[0133] The catalyst particles contained in the CNT assembly wire bundle can contain at least one metal element selected from the group consisting of iron, nickel, cobalt, molybdenum, gold, silver, copper, yttrium, chromium, palladium, platinum, and tungsten. Here, the catalyst particles containing a metal element refers to both cases where the catalyst particles contain other elements (e.g., sulfur, oxygen, etc.) in addition to the metal element, and cases where the catalyst particles are composed only of the metal element.

[0134] The catalyst particles contained in the CNT-assembled wire bundle preferably contain iron. In this case, the catalyst particles may be, for example, iron particles consisting of only iron, or iron sulfide (FeS, Fe2S), or iron oxide (Fe2O3, Fe3O4). The catalyst particles are more preferably iron particles consisting of iron. Using iron as a catalyst is suitable from the viewpoint of mass production of CNTs. Therefore, when the catalyst particles contain iron, it is possible to mass-produce long CNT-assembled wire bundles.

[0135] The composition and content of the catalyst particles contained in the CNT-assembled wire bundle can be confirmed by energy dispersive X-ray spectrometry (EDX). The total content of the catalyst particles in the CNT-assembled wire bundle is preferably 0.01% to 50% by mass, more preferably 0.5% to 40%, and even more preferably 0.1% to 20%.

[0136] The carbon nanotube-aggregated wire bundle preferably contains elemental sulfur, and the elemental sulfur is preferably dispersed in the longitudinal direction of the carbon nanotube-aggregated wire bundle. Here, "elemental sulfur is dispersed in the longitudinal direction of the CNT-aggregated wire bundle" means that the elemental sulfur is not unevenly distributed in the longitudinal direction of the CNT-aggregated wire bundle.

[0137] The sulfur element originates from the auxiliary catalyst (CS2) used in the production of the CNT-aggregated wire bundle. In the CNT-aggregated wire bundle according to this embodiment, the sulfur element is dispersed in the longitudinal direction of the CNT-aggregated wire bundle, so that the sulfur element does not affect the electrical conductivity, mechanical strength, and other properties of the CNTs, and the CNT-aggregated wire bundle can be lengthened while maintaining these properties.

[0138] The fact that the CNT-aggregate wire bundle contains elemental sulfur and the amount of elemental sulfur in the CNT-aggregate wire bundle can be confirmed and measured by EDX, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The amount of elemental sulfur in the CNT-aggregate wire bundle is preferably 0.1% to 20%, more preferably 1% to 15%, and even more preferably 2% to 10%, based on the number of atoms.

[0139] The fact that the sulfur element contained in the CNT assembly wire bundle is dispersed in the longitudinal direction of the carbon nanotube assembly wire can be confirmed by EDX or EELS, which can be measured simultaneously with an electron microscope such as SEM or TEM.

[0140] (elongation at break, breaking strength, Young's modulus) The carbon nanotube assembly wire bundle preferably has an elongation at break of 0.1% or more and a breaking strength of 1 GPa or more, so that the CNT assembly wire bundle has excellent mechanical strength.

[0141] The lower limit of the elongation at break of the CNT-assembled wire bundle is preferably 0.1% or more, more preferably 1% or more, and even more preferably 5% or more. The upper limit of the elongation at break of the CNT-assembled wire bundle is not particularly limited, but can be, for example, 50% or less. The elongation at break of the CNT-assembled wire bundle is preferably 0.1% or more and 50% or less, preferably 1% or more and 40% or less, and even more preferably 5% or more and 30% or less.

[0142] The lower limit of the breaking strength of the CNT-assembled wire bundle is preferably 1 GPa or more, more preferably 3 GPa or more, and even more preferably 10 GPa or more. The upper limit of the breaking strength of the CNT-assembled wire bundle is not particularly limited, but can be, for example, 100 GPa or less. The breaking strength of the CNT-assembled wire bundle is preferably 1 GPa or more and 100 GPa or less, more preferably 3 GPa or more and 50 GPa or less, and even more preferably 10 GPa or more and 30 GPa or less.

[0143] The carbon nanotube assembly wire bundle preferably has a Young's modulus of 10 GPa or more, which allows the CNT assembly wire bundle to have excellent mechanical strength.

[0144] The lower limit of the Young's modulus of the CNT-assembled wire bundle is preferably 10 GPa or more, more preferably 100 GPa or more, and even more preferably 300 GPa or more. The upper limit of the Young's modulus of the CNT-assembled wire bundle is not particularly limited, but is preferably 1500 GPa or less. The Young's modulus of the CNT-assembled wire bundle is preferably 10 GPa or more and 1500 GPa or less, more preferably 100 GPa or more and 1200 GPa or less, and even more preferably 300 GPa or more and 1000 GPa or less.

[0145] The elongation at break, breaking strength, and Young's modulus of the CNT assembly wire bundle are measured by conducting a break test. The break test method is as follows. A CNT assembly wire approximately 3 cm long is prepared, and both ends are fixed to a tensile fixture plate with adhesive. One end of the fixture plate to which the CNT assembly wire is fixed is pulled, and the tensile stress and elongation are measured until the 1 cm CNT assembly wire not fixed with adhesive breaks (measuring equipment: Imada's "Load-displacement measuring unit (FSA-1KE-5N)"). This gives a stress-strain curve. Young's modulus is evaluated from the slope of the linear region of the stress-strain curve during the initial deformation process.

[0146] (1st element content) The carbon nanotube assembly wire bundle preferably contains 10 mass % or less in total of at least one first element selected from the group consisting of iron, sulfur, nickel, cobalt, molybdenum, gold, silver, copper, yttrium, chromium, palladium, platinum, and tungsten.

[0147] If the total content of the first elements exceeds 10 mass%, composite particles containing the first elements tend to be formed. If the CNT-aggregated wire bundle contains composite particles, the breaking strength of the CNT-aggregated wire bundle tends to decrease. Therefore, if the total content of the first elements in the CNT-aggregated wire bundle is 10 mass% or less, the decrease in breaking strength caused by the formation of composite particles can be suppressed, and the CNT-aggregated wire bundle can have excellent mechanical strength.

[0148] The upper limit of the total content of the first element in the CNT-aggregated wire bundle is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less. The lower limit of the total content of the first element in the CNT-aggregated wire bundle is not particularly limited, but may be 0.01% by mass or more from the viewpoint of manufacturing. The total content of the first element in the CNT-aggregated wire bundle is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.05% by mass or more and 5% by mass or less, and even more preferably 0.1% by mass or more and 1% by mass or less.

[0149] The total content of the first element in the CNT assembly wire bundle can be measured by energy dispersive X-ray spectrometry (EDX).

[0150] [Embodiment 3-1: Method for manufacturing carbon nanotube assembly wire (1)] The manufacturing method of the carbon nanotube aggregate wire according to the embodiment 3-1 is the manufacturing method of the carbon nanotube aggregate wire according to the embodiment 1. The manufacturing method of the carbon nanotube aggregate wire according to the embodiment 3-1 can include a growing step (hereinafter also referred to as the growing step) of growing one or more carbon nanotubes from each of the plurality of catalyst particles by supplying a carbon-containing gas to the plurality of catalyst particles in a suspended state, an elongating step (hereinafter also referred to as the elongating step) of elongating the plurality of carbon nanotubes in a suspended state by applying a tensile force to the plurality of carbon nanotubes, and an assembling step (hereinafter also referred to as the assembling step) of orienting and assembling the plurality of carbon nanotubes in a suspended state in a direction along the flow of the carbon-containing gas to obtain a carbon nanotube aggregate wire.

[0151] The carbon nanotube assembly wire according to the first embodiment can be produced by, for example, a carbon nanotube assembly wire production apparatus 20 shown in Fig. 14. The carbon nanotube assembly wire production apparatus 20 can include a tubular carbon nanotube growth section (hereinafter also referred to as CNT growth section) 21, a gas supply section 22 that supplies a carbon-containing gas from one end (the end on the right side in Fig. 14) of the CNT growth section 21 into the CNT growth section 21, a catalyst supply section 23 that supplies catalyst particles P into the CNT growth section 21, and a carbon nanotube assembly section 24 (hereinafter also referred to as CNT assembly section) that is disposed on the other end side (the end on the left side in Fig. 14) of the CNT growth section 21 and aligns and assembles a plurality of carbon nanotubes obtained in the CNT growth section 21 in a direction along the flow of the carbon-containing gas.

[0152] <Growth process> In the growing step, a carbon-containing gas is supplied to the plurality of catalyst particles in suspension, so that one or more carbon nanotubes are grown from each of the plurality of catalyst particles. In the present specification, in the growing step, the length of the CNT is 20 μm or less.

[0153] The growth step is carried out inside the CNT growth section 21. The growth step is preferably carried out under temperature conditions of 800°C or more and 1200°C or less. If the temperature is less than 800°C, the growth rate of the CNTs tends to slow down. On the other hand, if the temperature exceeds 1200°C, the content of impurity carbon tends to increase. Here, impurity carbon means carbon substances other than CNTs. For example, amorphous carbon and graphite microcrystals are included. The temperature conditions of the growth step are more preferably 900°C or more and 1150°C or less, and even more preferably 950°C or more and 1050°C or less.

[0154] The catalyst particles P are supplied into the CNT growth section 21 when the catalyst 27 arranged inside the catalyst supply section 23 collapses due to the wind pressure of the carbon-containing gas supplied from the gas supply section 22 to the catalyst supply section 23 and the CNT growth section 21, and becomes catalyst particles P.

[0155] For example, iron, nickel, cobalt, molybdenum, gold, silver, copper, palladium, and platinum can be used as the catalyst particles P. Among them, the use of iron is preferable from the viewpoint of mass production of long CNTs.

[0156] The carbon-containing gas is supplied to the CNT growth section 21 from the gas supply section 22 via the catalyst supply section 23. A gas having reducing properties such as a hydrocarbon gas is used as the carbon-containing gas. For example, a mixed gas of methane and argon, a mixed gas of ethylene and argon, or a mixed gas of ethanol and argon can be used as such a carbon-containing gas. The carbon-containing gas preferably contains carbon disulfide (CS2) as an auxiliary catalyst.

[0157] The lower limit of the average flow velocity of the carbon-containing gas supplied from the gas supply unit 22 in the CNT growth unit is 0.05 cm / sec, preferably 0.10 cm / sec, and more preferably 0.20 cm / sec. On the other hand, the upper limit of the average flow velocity in the CNT growth unit 21 is preferably 10.0 cm / sec, and more preferably 5.0 cm / sec. If the average flow velocity of the carbon-containing gas in the CNT growth unit 21 does not meet the above lower limit, the carbon source gas supplied to the catalyst particles P tends to be insufficient, and the growth of the carbon nanotubes formed between the catalyst particles P tends to stagnate. Conversely, if the average flow velocity of the carbon-containing gas in the CNT growth unit 21 exceeds the above upper limit, the carbon nanotubes tend to be peeled off from the catalyst particles P, stopping the growth of the carbon nanotubes, thereby inhibiting the formation of the carbon nanotubes.

[0158] The lower limit of the Reynolds number of the flow of the carbon-containing gas supplied from the gas supply unit 22 in the CNT growth unit 21 is preferably 0.01, more preferably 0.05. On the other hand, the upper limit of the Reynolds number is 1000, preferably 100, more preferably 10. If the Reynolds number is less than the lower limit, the design of the device is excessively restricted, so that the carbon nanotube assembly wire manufacturing device 20 may become unnecessarily expensive and the manufacturing efficiency of the carbon nanotubes may unnecessarily decrease. If the Reynolds number exceeds the upper limit, the flow of the carbon-containing gas is disturbed, which tends to inhibit the generation of carbon nanotubes on the catalyst particles P.

[0159] The length of the CNTs obtained by the growth step is preferably 0.1 μm or more and 20 μm or less. If the length of the CNTs obtained by the growth step is less than 0.1 μm, adjacent CNTs tend to be entangled without being oriented in the longitudinal direction, and to form secondary particles. On the other hand, if the length of the CNTs exceeds 20 μm, the time until the elongation step is performed becomes longer, and the production efficiency of carbon nanotubes tends to decrease unnecessarily. The length of the CNTs obtained by the growth step is more preferably 0.5 μm or more and 15 μm or less, and even more preferably 1 μm or more and 10 μm or less. The length of the CNTs can be measured by observation with a scanning electron microscope.

[0160] <Extension process> Next, a tensile force is applied to the plurality of suspended carbon nanotubes obtained in the growth step, thereby elongating the plurality of carbon nanotubes.

[0161] The elongation step is carried out inside the CNT growth section 21 and the CNT assembly section 24, or inside the CNT assembly section 24. When the elongation step is carried out inside the CNT growth section 21, it is preferable that the elongation step is carried out on the downstream side of the carbon-containing gas of the CNT growth section 21, i.e., on the CNT assembly side.

[0162] The tensile force is preferably applied to the carbon nanotubes by changing the flow rate of the carbon-containing gas. For example, by making the average flow rate of the carbon-containing gas on the downstream side greater than the average flow rate of the carbon-containing gas on the upstream side, a tensile force can be applied to the CNTs in the downstream direction. When the tensile force acts on the end of the carbon nanotube, the carbon nanotube extending from the catalyst particle P is pulled, and is plastically deformed to shrink in diameter and elongate in the longitudinal direction.

[0163] In the elongation step, the carbon nanotubes are preferably elongated while being oriented in the direction along the flow of the carbon-containing gas. This is believed to result in a carbon nanotube that is less likely to bend and has a straight tube portion T made only of carbon in a six-membered ring. Carbon nanotubes made only of carbon in a six-membered ring are less likely to deteriorate and can maintain their quality.

[0164] The average flow velocity of the carbon-containing gas on the downstream side is preferably 0.051 cm / sec or more and 10.001 cm / sec or less, more preferably 0.201 cm / sec or more and 5.001 cm / sec or less. If the average flow velocity of the carbon-containing gas on the downstream side is less than 0.051 cm / sec, the extension speed of the carbon nanotubes tends not to be sufficiently faster than the growth speed. On the other hand, if the average flow velocity of the carbon-containing gas on the downstream side is more than 10.001 cm / sec, the carbon nanotubes tend to be peeled off from the catalyst particles P, stopping the growth of the carbon nanotubes, thereby inhibiting the formation of the carbon nanotubes.

[0165] The average flow velocity of the carbon-containing gas on the upstream side is preferably 0.050 cm / sec or more and 10,000 cm / sec or less, more preferably 0.200 cm / sec or more and 5,000 cm / sec or less. If the average flow velocity of the carbon-containing gas on the upstream side is less than 0.050 cm / sec, the wind pressure is insufficient and the growth of the carbon nanotubes formed between the catalyst particles P tends to stagnate. On the other hand, if the average flow velocity of the carbon-containing gas on the upstream side exceeds 10,000 cm / sec, the carbon nanotubes tend to peel off from the catalyst particles P, stopping the growth of the carbon nanotubes, thereby inhibiting the formation of the carbon nanotubes.

[0166] A method for making the average flow velocity of the carbon-containing gas on the downstream side larger than that on the upstream side of the carbon-containing gas can be, for example, making the cross-sectional area of ​​the hollow portion through which the carbon-containing gas passes smaller on the downstream side of the carbon-containing gas than on the upstream side of the carbon-containing gas. More specifically, the cross-sectional area of ​​the hollow portion through which the carbon-containing gas passes in the CNT assembly portion (corresponding to the downstream side) can be made smaller than the cross-sectional area of ​​the hollow portion through which the carbon-containing gas passes in the CNT growth portion (corresponding to the upstream side). This generates an acceleration field near the region where the cross-sectional area of ​​the hollow portion is smaller, and the flow velocity of the carbon-containing gas increases.

[0167] The tensile force is preferably applied to the plurality of carbon nanotubes by using a magnetic field. A specific example of using a magnetic field as the tensile force will be described with reference to FIG. 15. FIG. 15 is a diagram showing the periphery of a magnetic field generating section of a CNT assembly wire manufacturing apparatus 20a. As shown in FIG. 15, in a CNT assembly section 24a located downstream of a carbon-containing gas, an electric wire 55 is arranged in a coil shape around a reaction tube 31, and a current is passed through the electric wire, so that a magnetic force in a direction along the central axis of the reaction tube 31 is generated inside the reaction tube 31. line By generating magnetic field 32, a tensile force derived from the magnetic field can be applied to the CNTs. By applying a magnetic field during CNT elongation, the magnetic force acts directly on the metal contained in the CNTs, which allows the CNTs to be oriented in the direction along the magnetic field lines 32 inside the reaction tube and elongate.

[0168] 15 shows the case where the CNTs are elongated and aggregated by the magnetic field, but the elongation and aggregation of the CNTs do not have to occur simultaneously. In other words, the CNTs may only be elongated by the magnetic field, without being aggregated. In this case, the electric wire 30 is placed downstream of the carbon-containing gas of the CNT growth section 21, and a magnetic field is generated in the CNT growth section 21.

[0169] The tensile force is preferably applied to the plurality of carbon nanotubes by using an electric field. A specific example of the case where an electric field is used as the tensile force will be described with reference to FIG. 16. FIG. 16 is a diagram showing the periphery of an electric field generating section of a CNT assembly wire manufacturing apparatus 20b. As shown in FIG. 16, in a CNT assembly section 24b, a positive electrode 33 made of a conductive material is installed on the downstream side of a carbon-containing gas, and a negative electrode 34 made of a conductive material is installed on the upstream side, and an electric field is generated along the central axis of a reaction tube 31, so that a tensile force derived from an electric field can be applied to the CNTs. By applying an electric field during CNT elongation, an electrostatic force acts directly on the CNTs and the metal contained in the CNTs, and the CNTs can be oriented and elongated in a direction along the electric field line.

[0170] 16 shows a case where the CNTs are elongated and aggregated by the electric field, but the elongation and aggregation of the CNTs do not have to occur simultaneously. In other words, the CNTs may only be elongated by the electric field, without being aggregated. In this case, the + electrode 33 and the - electrode 34 are placed downstream of the carbon-containing gas of the CNT growth section 21, and an electric field is generated in the CNT growth section 21.

[0171] Even while the carbon nanotube is being stretched by the tensile force, a carbon nanotube having the original diameter grows on the catalyst particle P. Therefore, the carbon nanotube produced through the stretching process can have a tubular tube portion T and a conical cone portion C whose diameter is continuously enlarged from the end of the tube portion, as shown in Fig. 6.

[0172] In other words, in the elongation process, the carbon nanotube formed by the vapor phase growth method is stretched by tensile force at the same time as it is formed, so that some of the hexagonal cells of the carbon nanotube are rearranged into pentagonal cells to form a cone-shaped portion, and then rearranged again into hexagonal cells to form a tube portion which is a carbon nanotube with a smaller diameter.

[0173] In the elongation step, the carbon nanotubes grown on the catalyst particles P are grown while being stretched using a tensile force, so that the tube portion can be formed at a speed that is extremely faster than the growth speed of the carbon nanotubes on the catalyst particles P. Thus, a long carbon nanotube can be formed in a relatively short time. Therefore, even if the time for which the conditions for continuously growing carbon nanotubes on the catalyst particles P can be maintained is short, a sufficiently long carbon nanotube can be formed.

[0174] In the elongation step, it is believed that the incorporation of carbon atoms into the growth points of the carbon nanotubes is promoted by applying a tensile force to the carbon nanotubes on the catalyst particles P. This is believed to increase the growth rate of the carbon nanotubes, and therefore the rate at which the length of the resulting carbon nanotubes increases.

[0175] In the elongation process, it is believed that the application of a tensile force to the carbon nanotube on the catalyst particle P makes it difficult for the carbon nanotube to bend, and that it is possible to obtain a straight carbon nanotube having a cylindrical body with the tube portion T made of a sheet consisting of only six-membered carbon rings. Carbon nanotubes consisting only of six-membered carbon rings are less susceptible to deterioration and can maintain their quality.

[0176] The length of the CNT obtained by the elongation step is preferably 10 μm or more, more preferably 100 μm or more. In particular, a carbon nanotube length of 100 μm or more is suitable from the viewpoint of producing a CNT assembly wire. The upper limit of the length of the carbon nanotube is not particularly limited, but from the viewpoint of production, it is preferably 600 mm or less. The length of the CNT can be measured by observing with a scanning electron microscope.

[0177] <Assembling process> Next, the plurality of carbon nanotubes in the suspended state are aligned in the direction along the flow of the carbon-containing gas and assembled to obtain a carbon nanotube assembly wire.

[0178] A method for orienting and assembling a plurality of suspended CNTs in the direction along the flow of the carbon-containing gas includes bringing a plurality of carbon nanotubes close to each other in an oriented state. For example, the cross-sectional area of ​​the hollow portion of the CNT assembly portion through which the carbon-containing gas passes is made smaller than the cross-sectional area of ​​the hollow portion of the CNT growth portion or the CNT extension portion through which the carbon-containing gas passes. More specifically, the CNT assembly portion is made into a honeycomb structure, and the honeycomb structure is arranged so that the longitudinal direction of the through-holes is in the direction along the flow of the carbon-containing gas.

[0179] In this specification, the honeycomb structure means a porous body having a large number of thin cylindrical through-holes, as shown in a honeycomb structure 29 in FIG.

[0180] When the CNT assembly portion is made of a honeycomb structure, the cross-sectional area of ​​one through hole is 0.05 mm 2 More than 100mm 2 Less than 0.1mm is preferable. 2 More than 50mm 2 Less than 0.5mm is more preferable. 2 More than 10mm 2 More preferably, the cross-sectional area of ​​one through hole is 0.05 mm 2 If the cross-sectional area of ​​one through hole is less than 100 mm2, the CNTs tend to clog the inside of the through hole. 2 If the distance exceeds this value, the CNTs tend not to come close enough to each other and are unable to aggregate.

[0181] When the CNT aggregate portion is made of a honeycomb structure, the length in the direction along the through-holes of the honeycomb structure (longitudinal direction) is preferably 1 mm to 1 m, more preferably 10 mm to 50 cm, and even more preferably 15 mm to 10 cm. If the length in the direction along the through-holes of the honeycomb structure is less than 1 mm, the CNTs floating in the gas phase tend not to be sufficiently accelerated, and the growth promotion effect tends to be suppressed. On the other hand, if the length in the direction along the through-holes of the honeycomb structure exceeds 1 m, the amount of CNTs deposited on the inner walls of the through-holes increases, making it difficult to recover the CNTs.

[0182] The average flow velocity of the carbon-containing gas at the CNT assembly is preferably 0.05 cm / sec or more and 10 cm / sec or less, more preferably 0.2 cm / sec or more and 5 cm / sec or less. If the average flow velocity of the carbon-containing gas is less than 0.05 cm / sec, a thin film of non-oriented CNTs tends to be obtained. On the other hand, if the average flow velocity of the carbon-containing gas exceeds 10 cm / sec, the carbon-containing gas that reaches the CNT assembly without reacting tends to cause an incomplete decomposition reaction, resulting in the adhesion of tar.

[0183] In the above, the case where the aggregation step is performed after the elongation step has been described, but the elongation step and the aggregation step can be performed simultaneously. Also, after the elongation step, the elongation step and the aggregation step can be performed simultaneously. For example, when a honeycomb structure is used as the CNT aggregation portion, the elongation and aggregation of the CNTs are performed simultaneously in the through-holes of the honeycomb structure.

[0184] According to the above-mentioned method for producing a CNT aggregated wire, a carbon-containing gas is continuously supplied to the catalyst supply section, the CNT growth section, and the CNT aggregated section, thereby making it possible to continuously produce a CNT aggregated wire without any length restrictions. The length of the CNT aggregated wire can be appropriately adjusted by adjusting the flow rate, supply time, etc. of the carbon-containing gas.

[0185] The length of the CNT aggregated wire obtained by the assembly step is preferably 100 μm or more, more preferably 1000 μm or more, and even more preferably 10000 μm or more. The upper limit of the length of the CNT aggregated wire is not particularly limited, but from the viewpoint of production, it is preferably 1 m or less. The length of the CNT aggregated wire can be measured by observing with an optical microscope or with the naked eye.

[0186] [Embodiment 3-2: Method for manufacturing carbon nanotube assembly wire (2)] Another example of the manufacturing method of the carbon nanotube aggregate wire according to the embodiment 1 will be described in the embodiment 3-2. The manufacturing method of the carbon nanotube aggregate wire according to the embodiment 3-2 includes a mist generating step (hereinafter also referred to as a mist generating step) of generating a mist containing a plurality of catalyst particles and a liquid carbon source, a growing step (hereinafter also referred to as a growing step) of growing one or a plurality of carbon nanotubes from each of the plurality of catalyst particles by heating the mist, an elongation step (hereinafter also referred to as an elongation step) of elongating the plurality of carbon nanotubes by applying a tensile force to the plurality of carbon nanotubes in a suspended state, and an assembly step (hereinafter also referred to as an assembly step) of orienting and assembling the plurality of carbon nanotubes in a longitudinal direction to obtain a carbon nanotube aggregate wire.

[0187] In the method for producing the carbon nanotube aggregated wire according to the embodiment 3-2, for example, a carbon nanotube aggregated wire production apparatus 20c shown in FIG. 18 can be used.

[0188] The carbon nanotube assembly wire manufacturing apparatus 20c can include a mist generating unit 37 that generates a mist containing a plurality of catalyst particles and a liquid carbon source, a tubular carbon nanotube growth unit 21 that is connected to the mist generating unit 37 and grows one or more carbon nanotubes from each of the plurality of catalyst particles P by heating the mist 39, and a carbon nanotube assembly unit 24 that is disposed at one end side of the carbon nanotube growth unit 21 (the left end in Figure 18) and orients and aggregates the plurality of carbon nanotubes obtained in the carbon nanotube growth unit 21 in a direction along their longitudinal direction to obtain a carbon nanotube assembly wire.

[0189] <Mist generation process> In the mist generating step, a mist 39 containing a plurality of catalyst particles and a liquid carbon source is generated. The mist generating step is performed using a mist generator 60.

[0190] The mist generating process can include a preparation process of preparing a mist raw material liquid containing catalyst particles and a liquid carbon source, and an atomization process of atomizing the mist raw material liquid by applying ultrasonic vibrations to the mist raw material liquid.

[0191] The mist obtained by atomizing the mist raw material liquid preferably has an average particle size of 0.1 μm or more and 50 μm or less, more preferably 1 μm or more and 40 μm or less, and even more preferably 10 μm or more and 30 μm or less. If the average particle size of the mist is less than 0.1 μm, the growth of the catalyst having a particle size suitable for the growth of CNTs tends to be suppressed. On the other hand, if the average particle size of the mist exceeds 50 μm, the enlargement of the catalyst particles is promoted, and the growth efficiency of CNTs tends to decrease.

[0192] Here, the "average particle size" of the mist means the median size (d50) in the volumetric particle size distribution (volume distribution), and means the average particle size of all mist particles contained in the mist. In this specification, the "average particle size" may also be referred to simply as "particle size."

[0193] The particle size of each mist particle for calculating the particle size (volume average particle size) of the mist can be measured by the following method. First, mist is generated using a mist generator. The generated mist is irradiated with laser light using a dynamic light scattering particle size distribution analyzer, and the particle size distribution is obtained by detecting the intensity distribution of scattered light due to Brownian motion that depends on the particle size.

[0194] The catalyst particles in the mist raw material liquid may be particles containing at least one metal element selected from the group consisting of iron, nickel, cobalt, molybdenum, gold, silver, copper, yttrium, chromium, palladium, platinum, and tungsten. Here, the catalyst particles containing a metal element means both the case where the catalyst particles contain other elements (e.g., sulfur, oxygen, etc.) in addition to the metal element, and the case where the catalyst particles are composed only of the metal element.

[0195] The catalyst particles in the mist raw material liquid preferably contain iron. In this case, the catalyst particles may be made of, for example, iron oxide (Fe2O3), ferrocene (Fe(C5H5)2), etc. Among them, the catalyst particles are more preferably made of iron oxide. Using iron oxide as the catalyst particles in the mist raw material liquid is suitable from the viewpoint of mass production of CNTs. Therefore, when the catalyst particles in the mist raw material liquid contain iron oxide, it is possible to mass produce a long CNT aggregate wire.

[0196] The average particle diameter of the catalyst particles in the mist raw material liquid is preferably 0.6 nm or more and less than 200 nm. This allows the average particle diameter of the catalyst particles contained in the CNT aggregate wire to be 0.6 nm or more and less than 30 nm. The average particle diameter of the catalyst particles in the mist raw material liquid is more preferably 1 nm or more and 100 nm or less, and further preferably 2 nm or more and 50 nm or less.

[0197] Liquid carbon sources can include ethanol, methanol, isopropyl alcohol, benzene, toluene, and xylene. Among these, ethanol is preferred because it is a widely used reagent and has very low toxicity to the human body, and because it contains oxygen, it can suppress the generation of amorphous carbon.

[0198] The mist raw material liquid may contain, in addition to the catalyst particles and the liquid carbon source, carbon disulfide, thiophene, etc. Carbon disulfide and thiophene function as auxiliary catalysts.

[0199] The content of catalyst particles in the mist raw material liquid is preferably 0.01% by mass or more and 5% by mass or less, more preferably 0.1% by mass or more and 4% by mass or less, and even more preferably 0.5% by mass or more and 2% by mass or less. If the content of catalyst particles in the mist raw material liquid is less than 0.01% by mass, the production efficiency of CNTs tends to decrease. On the other hand, if the content of catalyst particles in the mist raw material liquid exceeds 5% by mass, the catalyst particles tend to become coarse.

[0200] The content of the liquid carbon source in the mist raw material liquid is preferably 95% by mass or more and 99.99% by mass or less, more preferably 96% by mass or more and 99.9% by mass or less, and even more preferably 98% by mass or more and 99.5% by mass or less. If the content of the liquid carbon source in the mist raw material liquid is less than 95% by mass, the production efficiency of CNTs tends to decrease. On the other hand, if the content of the liquid carbon source in the mist raw material liquid exceeds 99.99% by mass, the amount of amorphous carbon produced tends to increase due to the high carbon source concentration relative to the amount of catalyst added.

[0201] A specific example of a method for applying ultrasonic vibration to the mist raw material liquid will be described with reference to Figures 19 to 21. Figures 19 to 21 are diagrams showing an example of the mist generating unit 37 (Figure 18).

[0202] 19 includes a reaction tube 31 continuous with the reaction tube constituting the CNT growth section 21, and a mist generator 60a connected to the reaction tube 31. That is, the mist generating section 37a is connected to the CNT growth section 21.

[0203] The mist generator 60a has a horn transducer 41a and a mesh 42 arranged opposite to the vibration surface of the horn transducer 41a. The mist raw material liquid 38 is supplied between the vibration surface of the horn transducer 41a and the mesh 42. The horn transducer 41a applies ultrasonic vibration to the mist raw material liquid 38 supplied between the vibration surface of the horn transducer 41a and the mesh 42. This causes the mist raw material liquid 38 to pass through holes in the mesh and become atomized, becoming mist 39.

[0204] A connection part 45 connected to the reaction tube 31 is provided on the upper part of the mesh 42. The mist 39 generated by the mist generator 60a is supplied to the inside of the reaction tube 31 through the connection part 45.

[0205] The connection part 45 may be provided with a gas inlet 40 for introducing gas from the outside. A carrier gas such as argon is introduced from the gas inlet 40. The introduction of the carrier gas can promote the supply of mist into the reaction tube 31. In addition, the flow rate of the carrier gas can be changed to adjust the flow rate of the gas in the CNT growth part and the CNT extension part.

[0206] In this specification, a mesh is defined as a thin plate having a plurality of minute openings. The shape of the openings may be circular, elliptical, polygonal, etc. Among them, a circular shape is preferable from the viewpoint of generating mist with a uniform particle size.

[0207] 19, mist raw material liquid 38 is atomized by passing through holes in mesh 42. Therefore, by adjusting the diameter of the openings in the mesh, the average particle size of the mist can be adjusted to a desired size.

[0208] The mesh preferably has an opening diameter of 1 μm to 50 μm, more preferably 3 μm to 40 μm, and even more preferably 5 μm to 30 μm. When the opening diameter is 1 μm to 50 μm, the average particle diameter of the mist after passing through the mesh can be 0.1 μm to 50 μm. When the opening diameter is less than 1 μm, clogging tends to occur. On the other hand, when the opening diameter exceeds 50 μm, the catalyst particles tend to become coarse during the heat treatment step in the CNT growth process. Here, the opening diameter is defined as the diameter of a circle having the same opening area (the equivalent diameter of a circle having the same opening area).

[0209] The mesh has 2 openings per mm 2 More than 400 pieces / mm 2 Preferably less than 10 pieces / mm 2 More than 200 pieces / mm 2 Less than 20 pieces / mm is more preferable. 2 More than 100 pieces / mm 2 More preferably, the number of openings is 2 / mm 2 If the number of openings is less than 400 / mm, the efficiency of mist generation tends to decrease significantly. 2 If the pressure exceeds this value, the droplets tend to condense after the mist is generated, hindering the formation of fine catalyst particles.

[0210] The thickness of the mesh is preferably 1 μm or more and 500 μm or less, more preferably 5 μm or more and 250 μm or less, and even more preferably 10 μm or more and 100 μm or less. If the thickness of the mesh is less than 1 μm, the durability tends to decrease with repeated use. On the other hand, if the thickness of the mesh is more than 500 μm, ultrasonic vibration cannot be efficiently applied, and mist generation tends to be inhibited.

[0211] The mesh may be made of, for example, stainless steel. The frequency of the horn vibrator is preferably 50 kHz or more and 400 kHz or less, more preferably 70 kHz or more and 300 kHz or less, and even more preferably 100 kHz or more and 200 kHz or less. If the frequency of the horn vibrator is less than 50 kHz, the mist generation efficiency tends to decrease, which is not preferable. On the other hand, if the frequency of the horn vibrator is more than 400 kHz, the mesh tends to deteriorate early, which is not preferable.

[0212] 20 includes a reaction tube 31 continuous with the reaction tube constituting the CNT growth section 21, and a mist generator 60b connected to the reaction tube 31. That is, the mist generating section 37b is connected to the CNT growth section 21.

[0213] The mist generator 60b includes a first container 47 that holds water 43, an oscillator 41b disposed at the bottom of the first container 47, and a second container 48 disposed inside the first container 47. At least a portion of the outer surface of the second container 48 is in contact with the water 43. The second container 48 contains a mist raw material liquid 38 inside. The second container is provided with a gas inlet 40 that introduces gas from the outside, and a connection part 45 that is connected to the reaction tube 31.

[0214] A carrier gas such as argon is introduced from the gas inlet 40. The introduction of the carrier gas can promote the supply of mist into the reaction tube 31. In addition, the flow rate of the carrier gas can be changed to adjust the flow rate of the gas in the CNT growth section and the CNT extension section.

[0215] The oscillator 41b vibrates to give ultrasonic vibration energy to the water. The ultrasonic vibration energy is concentrated on the surface of the mist raw material liquid 38, and the mist raw material liquid 38 is atomized by the vibration (cavitation effect) to become mist 39. The mist 39 is supplied into the reaction tube 31 through the connection part 45 together with the gas taken in from the gas inlet 40.

[0216] 21 includes a reaction tube 31 that is continuous with the reaction tube that constitutes the CNT growth section 21, and a mist generator 60c that is connected to the reaction tube 31. That is, the mist generating section 37c is connected to the CNT growth section 21.

[0217] The mist generating device 60c comprises a container 49 in which the mist raw material liquid 38 is stored, an air inlet 44 for introducing compressed air generated from a compressor (not shown) into the inside of the container 49, a nozzle portion 52 arranged continuously above the air inlet 44, a baffle 51 arranged above the nozzle portion 52, and piping 53 for bringing the mist raw material liquid 38 to the vicinity of the nozzle portion 52.

[0218] When the compressed air introduced from the air inlet 44 is discharged from the nozzle part 52, a negative pressure action is generated between the nozzle part 52 and the piping 53. Due to the negative pressure action, the mist raw material liquid 38 is sucked up to the upper part of the piping 53, collides with the baffle 51, and is atomized to become the mist 39. The mist 39 is supplied into the reaction tube 31 through the connection part 45.

[0219] The connection part 45 may be provided with a gas inlet 40 for introducing gas from the outside. A carrier gas such as argon is introduced from the gas inlet 40. The introduction of the carrier gas can promote the supply of mist into the reaction tube 31. In addition, the flow rate of the carrier gas can be changed to adjust the flow rate of the gas in the CNT growth part and the CNT extension part.

[0220] <Growth process> In the growing step, the mist 39 is heated to grow one or more carbon nanotubes from each of the plurality of catalyst particles P. The growing step is performed inside the CNT growing portion 21.

[0221] By heating the mist, CNTs grow on the catalyst particles P in the mist using the liquid carbon source contained in the mist as a raw material. In this embodiment, the liquid carbon source contained in the mist is used as the carbon source for CNTs, so there is no need to use the carbon-containing gas used in the above embodiment 3-1. This is an advantage from the viewpoint of simplifying the CNT manufacturing process and reducing costs.

[0222] The temperature at which the mist is heated is preferably 800°C or higher and 1200°C or lower. That is, the growth step is preferably performed under temperature conditions of 800°C or higher and 1200°C or lower. If the temperature is lower than 800°C, the growth rate of CNTs tends to slow down. On the other hand, if the temperature exceeds 1200°C, the content of impurity carbon tends to increase. The temperature conditions of the growth step are more preferably 900°C or higher and 1150°C or lower, and even more preferably 950°C or higher and 1050°C or lower.

[0223] The lower limit of the average flow velocity of the carrier gas supplied from the gas inlet 40 in the CNT growth section is 0.05 cm / sec, preferably 0.10 cm / sec, and more preferably 0.20 cm / sec. On the other hand, the upper limit of the average flow velocity in the CNT growth section 21 is preferably 10.0 cm / sec, and more preferably 5.0 cm / sec. If the average flow velocity of the carrier gas in the CNT growth section 21 does not meet the lower limit, the mist tends to condense and liquefy in the furnace tube. Conversely, if the average flow velocity of the carrier gas in the CNT growth section 21 exceeds the upper limit, the carbon nanotubes tend to peel off from the catalyst particles P, stopping the growth of the carbon nanotubes, thereby inhibiting the formation of the carbon nanotubes.

[0224] The lower limit of the Reynolds number of the flow of the carrier gas supplied from the gas inlet 40 in the CNT growth section 21 is preferably 0.01, more preferably 0.05. On the other hand, the upper limit of the Reynolds number is 1000, preferably 100, more preferably 10. If the Reynolds number is less than the lower limit, the design of the device is excessively restricted, so that the carbon nanotube assembly wire manufacturing device 20 may become unnecessarily expensive, and the manufacturing efficiency of the carbon nanotubes may tend to be unnecessarily reduced. If the Reynolds number exceeds the upper limit, the flow of the carbon-containing gas tends to be disturbed, hindering the generation of carbon nanotubes on the catalyst particles P.

[0225] The length of the CNTs obtained by the growth step is preferably 0.1 μm or more and 20 μm or less. If the length of the CNTs obtained by the growth step is less than 0.1 μm, adjacent CNTs tend to be entangled without being oriented in the longitudinal direction, and to form secondary particles. On the other hand, if the length of the CNTs exceeds 20 μm, the time until the elongation step is performed becomes longer, and the production efficiency of carbon nanotubes tends to decrease unnecessarily. The length of the CNTs obtained by the growth step is more preferably 0.5 μm or more and 15 μm or less, and even more preferably 1 μm or more and 10 μm or less. The length of the CNTs can be measured by observation with a scanning electron microscope.

[0226] <Extension process, gathering process> The subsequent decompression and assembly steps are the same as those in the above-described embodiment 3-1, and therefore description thereof will not be repeated.

[0227] [Embodiment 4-1: Carbon nanotube assembly wire manufacturing device (1)] A carbon nanotube assembly wire manufacturing apparatus used for manufacturing the carbon nanotube assembly wire according to the first embodiment will be described with reference to Fig. 14. The carbon nanotube assembly wire manufacturing apparatus 20 shown in Fig. 14 can include a tubular carbon nanotube growth section (hereinafter also referred to as CNT growth section) 21, a gas supply section 22 that supplies a carbon-containing gas to the CNT growth section 21 from one end (the end on the right side in Fig. 14) of the CNT growth section 21, a catalyst supply section 23 that supplies catalyst particles P into the CNT growth section 21, and a carbon nanotube assembly section (hereinafter also referred to as CNT assembly section) 24 that is disposed on the other end side (the end on the left side in Fig. 14) of the CNT growth section 21 and aligns and assembles a plurality of carbon nanotubes obtained in the CNT growth section 21 in a direction along the flow of the carbon-containing gas. The CNT growth section 21, the CNT assembly section 24, and the catalyst supply section 23 include a continuous reaction tube 31, and the CNTs and the CNT assembly wire are manufactured inside the reaction tube 31.

[0228] <Carbon nanotube growth area> The carbon nanotube growing section 21 has a tubular shape made of, for example, a quartz tube. In the CNT growing section 21, the carbon nanotubes 2 are formed on the catalyst particles P by using a carbon-containing gas.

[0229] The carbon nanotube growing portion 21 is placed in an electric furnace 28 and heated by a heater (not shown).

[0230] The internal temperature of CNT growth section 21 is preferably 800° C. or more and 1200° C. or less. In order to maintain such a temperature, a heated carbon-containing gas may be supplied from gas supply section 22 to CNT growth section 21, or the carbon-containing gas may be heated in CNT growth section 21.

[0231] <Gas supply section> The gas supply unit 22 supplies a carbon-containing gas to the CNT growth unit 21 from one end (the end on the right side in FIG. 14) of the carbon nanotube growth unit 21. The gas supply unit 22 may be configured to include a gas cylinder (not shown) and a flow rate control valve (not shown).

[0232] The type of carbon-containing gas supplied from gas supply unit 22, the average flow velocity within the CNT growth section, and the Reynolds number of the flow within the CNT growth section can be the same as those described in the above-mentioned method for producing a CNT aggregate wire, and therefore the description will not be repeated.

[0233] It is preferable that the gas supply unit 22 can repeatedly change the amount of the carbon-containing gas supplied to the CNT growth unit 21. This increases or decreases the flow rate of the carbon-containing gas in the CNT growth unit 21, promoting separation of a plurality of aggregated catalyst particles, thereby increasing the number of carbon nanotubes obtained.

[0234] <Catalyst supply section> The catalyst supply unit 23 can be disposed between the gas supply unit 22 and the CNT growth unit 21. A catalyst holder 26 that holds a catalyst 27 is disposed inside the catalyst supply unit 23. A heater 25 is attached to the catalyst supply unit 23. That is, the catalyst supply unit 23 is heated by the heater.

[0235] The catalyst supply unit 23 supplies the catalyst 27, which is broken down by the wind pressure of the carbon-containing gas and divided into a plurality of catalyst particles P, into the flow of the carbon-containing gas. In this manner, by using the catalyst 27, a plurality of catalyst particles P in a high-temperature and contact state can be formed in the flow of the carbon-containing gas. Therefore, carbon nanotubes can be reliably grown between the plurality of catalyst particles.

[0236] Examples of catalyst 27 include ferrocene (Fe(C5H5)2), nickelocene (Ni(C5H5)2), cobaltocene (Co(C5H5)2, etc.). Among them, ferrocene is particularly preferable because of its excellent disintegration and catalytic action. When ferrocene is heated to a high temperature in catalyst supply section 23 and exposed to a carbon-containing gas, it is carburized to form iron carbide (Fe3C) on the surface, which is believed to disintegrate easily from the surface and gradually release catalyst fine particles P. In this case, the main component of the formed catalyst particles P is iron carbide or iron.

[0237] The lower limit of the average diameter of the catalyst particles P is preferably 30 nm, more preferably 40 nm, and even more preferably 50 nm. On the other hand, the upper limit of the average diameter of the catalyst particles P is preferably 1000 μm, more preferably 100 μm, and even more preferably 10 μm. When the average diameter of the catalyst particles P is less than the lower limit, the diameter of the carbon nanotubes formed by the catalyst particles is small, and the stretching rate is small, so that the carbon nanotubes tend not to be sufficiently long. On the other hand, when the average diameter of the catalyst particles exceeds the upper limit, it tends to be difficult to stretch the carbon nanotubes formed by the catalyst particles.

[0238] <Carbon nanotube assembly> The carbon nanotube assembly portion 24 is disposed at the end portion opposite to the gas supply portion 23 side of the CNT growth portion 21. That is, the CNT assembly portion 24 is disposed on the downstream side of the carbon-containing gas of the CNT growth portion 21. In the CNT assembly portion 24, a carbon nanotube assembly wire is formed.

[0239] The CNT assembly may have any structure as long as it can align and assemble a plurality of suspended carbon nanotubes in the direction along the flow of the carbon-containing gas. For example, the CNT assembly may be a honeycomb structure, a straight capillary structure, or the like.

[0240] When the CNT assembly portion is made of a honeycomb structure, the honeycomb structure is placed in the carbon nanotube assembly wire manufacturing apparatus so that the longitudinal direction of the through holes is aligned with the flow of the carbon-containing gas.

[0241] When the CNT assembly portion is made of a honeycomb structure, the configuration can be the same as that described in the above-mentioned method for producing a CNT aggregated wire, and therefore the description thereof will not be repeated.

[0242] The honeycomb structure may be made of ceramics (alumina, zirconia, aluminum nitride, silicon carbide, silicon nitride, forsterite, steatite, cordierite, mullite, ferrite, etc.), quartz glass, glass, metals, or graphite. Among these, it is preferable to make the honeycomb structure from the viewpoint of heat resistance and durability required during CNT production.

[0243] <Other configurations> 15, the CNT assembly wire manufacturing apparatus 20a may include a magnetic field generating unit 24a that generates a magnetic field in addition to the above configuration. The magnetic field generating unit 24a is configured by placing an electric wire 30 in a coil shape around the reaction tube 31 in the CNT growing unit 21 or the CNT assembly unit 24. By passing a current through the electric wire 30, a magnetic force in a direction along the central axis of the reaction tube 31 is generated inside the reaction tube 31. line By generating the magnetic field 32, a magnetic field can be generated, which allows a tensile force derived from the magnetic field to be applied to the CNT.

[0244] As shown in Fig. 16, the CNT assembly wire manufacturing apparatus 20b can include an electric field generating unit 24b that generates an electric field in addition to the above configuration. The electric field generating unit 24b is configured by installing a + electrode 33 made of a conductive material on the downstream side of the carbon-containing gas and a - electrode 34 made of a conductive material on the upstream side in the CNT growth unit 21 or the CNT assembly unit 24. This generates an electric field along the central axis of the reaction tube 31, thereby generating an electric field. This allows a tensile force derived from the electric field to be applied to the CNTs.

[0245] [Embodiment 4-2: Carbon nanotube assembly wire manufacturing device (2)] Another example of a carbon nanotube aggregate wire manufacturing apparatus used for manufacturing the carbon nanotube aggregate wire according to the first embodiment will be described with reference to Fig. 18 to Fig. 21. The carbon nanotube aggregate wire manufacturing apparatus 20c shown in Fig. 18 can include a mist generating unit 37 that generates a mist containing a plurality of catalyst particles and a liquid carbon source, a tubular carbon nanotube growing unit 21 that is connected to the mist generating unit 37 and grows one or a plurality of carbon nanotubes from each of the plurality of catalyst particles P by heating the mist 39, and a carbon nanotube assembly unit 24 that is disposed on one end side (the left end in Fig. 18) of the carbon nanotube growing unit 21 and aligns and assembles the plurality of carbon nanotubes obtained in the carbon nanotube growing unit 21 in a longitudinal direction to obtain a carbon nanotube aggregate wire.

[0246] <Mist generating section> In the mist generating section 37, a mist 39 containing a plurality of catalyst particles and a liquid carbon source is generated. In the mist generating section 37, ultrasonic vibration is applied to a mist raw material liquid 38 containing the catalyst particles and a liquid carbon source, thereby atomizing the mist raw material liquid 38 and generating a mist 39.

[0247] The mist obtained by atomizing the mist raw material liquid preferably has an average particle size of 0.1 μm to 50 μm, more preferably 1 μm to 40 μm, and even more preferably 10 μm to 30 μm. If the average particle size of the mist is less than 0.1 μm, catalyst growth of a particle size suitable for CNT growth tends to be suppressed. On the other hand, if the average particle size of the mist exceeds 50 μm, the enlargement of catalyst particles is promoted, and the growth efficiency of CNT tends to decrease.

[0248] Here, the "average particle size" of the mist means the median size (d50) in the volumetric particle size distribution (volume distribution), and means the average particle size of all mist particles contained in the mist. In this specification, the "average particle size" may also be referred to simply as "particle size."

[0249] The particle size of each mist particle for calculating the particle size (volume average particle size) of the mist can be measured by the following method. First, mist is generated using a mist generator. The generated mist is irradiated with laser light using a dynamic light scattering particle size distribution analyzer, and the particle size distribution is obtained by detecting the intensity distribution of scattered light due to Brownian motion that depends on the particle size.

[0250] As the catalyst particles in the mist raw material liquid, for example, particles containing at least one metal element selected from the group consisting of iron, nickel, cobalt, molybdenum, gold, silver, copper, yttrium, chromium, palladium, platinum, and tungsten can be used. Here, the catalyst particles containing a metal element means both the case where the catalyst particles contain other elements (e.g., sulfur, oxygen, etc.) together with the metal element, and the case where the catalyst particles are composed only of the metal element.

[0251] The catalyst particles in the mist raw material liquid preferably contain iron. In this case, the catalyst particles may be made of, for example, iron oxide (Fe2O3), ferrocene (Fe(C5H5)2), etc. Among them, the catalyst particles are more preferably made of iron oxide. Using iron oxide as the catalyst particles in the mist raw material liquid is suitable from the viewpoint of mass production of CNTs. Therefore, when the catalyst particles in the mist raw material liquid contain iron oxide, it is possible to mass produce a long CNT aggregate wire.

[0252] The average particle diameter of the catalyst particles in the mist raw material liquid is preferably 0.6 nm or more and less than 200 nm. This allows the average particle diameter of the catalyst particles contained in the CNT aggregate wire to be 0.6 nm or more and less than 30 nm. The average particle diameter of the catalyst particles in the mist raw material liquid is more preferably 1 nm or more and 100 nm or less, and further preferably 2 nm or more and 50 nm or less.

[0253] Liquid carbon sources can include ethanol, methanol, isopropyl alcohol, benzene, toluene, and xylene. Among these, ethanol is preferred because it is a widely used reagent and has very low toxicity to the human body, and because it contains oxygen, it can suppress the generation of amorphous carbon.

[0254] The mist raw material liquid may contain, in addition to the catalyst particles and the liquid carbon source, carbon disulfide, thiophene, etc. Carbon disulfide and thiophene function as auxiliary catalysts.

[0255] The content of catalyst particles in the mist raw material liquid is preferably 0.01% by mass or more and 5% by mass or less, more preferably 0.1% by mass or more and 4% by mass or less, and even more preferably 0.5% by mass or more and 2% by mass or less. If the content of catalyst particles in the mist raw material liquid is less than 0.01% by mass, the production efficiency of CNTs tends to decrease. On the other hand, if the content of catalyst particles in the mist raw material liquid exceeds 5% by mass, the catalyst particles tend to become coarse.

[0256] The content of the liquid carbon source in the mist raw material liquid is preferably 95% by mass or more and 99.99% by mass or less, more preferably 96% by mass or more and 99.9% by mass or less, and even more preferably 98% by mass or more and 99.5% by mass or less. If the content of the liquid carbon source in the mist raw material liquid is less than 95% by mass, the production efficiency of CNTs tends to decrease. On the other hand, if the content of the liquid carbon source in the mist raw material liquid exceeds 99.99% by mass, the amount of amorphous carbon produced tends to increase due to the high carbon source concentration relative to the amount of catalyst added.

[0257] A specific example of a method for applying ultrasonic vibration to the mist raw material liquid will be described with reference to Figures 19 to 21. Figures 19 to 21 are diagrams showing an example of the mist generating unit 37 (Figure 18).

[0258] 19 includes a reaction tube 31 continuous with the reaction tube constituting the CNT growth section 21, and a mist generator 60a connected to the reaction tube 31. That is, the mist generating section 37a is connected to the CNT growth section 21.

[0259] The mist generator 60a has a horn transducer 41a and a mesh 42 arranged opposite to the vibration surface of the horn transducer 41a. The mist raw material liquid 38 is supplied between the vibration surface of the horn transducer 41a and the mesh 42. The horn transducer 41a applies ultrasonic vibration to the mist raw material liquid 38 supplied between the vibration surface of the horn transducer 41a and the mesh 42. This causes the mist raw material liquid 38 to pass through holes in the mesh and become atomized, becoming mist 39.

[0260] A connection part 45 connected to the reaction tube 31 is provided on the upper part of the mesh 42. The mist 39 generated by the mist generator 60a is supplied to the inside of the reaction tube 31 through the connection part 45.

[0261] The connection part 45 may be provided with a gas inlet 40 for introducing gas from the outside. A carrier gas such as argon is introduced from the gas inlet 40. The introduction of the carrier gas can promote the supply of mist into the reaction tube 31. In addition, the flow rate of the carrier gas can be changed to adjust the flow rate of the gas in the CNT growth part and the CNT extension part.

[0262] In this specification, a mesh is defined as a thin plate having a plurality of minute openings. The shape of the openings may be circular, elliptical, polygonal, etc. Among them, a circular shape is preferable from the viewpoint of generating mist with a uniform particle size.

[0263] 19, mist raw material liquid 38 is atomized by passing through holes in mesh 42. Therefore, by adjusting the diameter of the openings in the mesh, the average particle size of the mist can be adjusted to a desired size.

[0264] The mesh preferably has an opening diameter of 1 μm to 50 μm, more preferably 3 μm to 40 μm, and even more preferably 5 μm to 30 μm. When the opening diameter is 1 μm to 50 μm, the average particle diameter of the mist after passing through the mesh can be 0.1 μm to 50 μm. When the opening diameter is less than 1 μm, clogging tends to occur. On the other hand, when the opening diameter exceeds 50 μm, the catalyst particles tend to become coarse during the heat treatment step in the CNT growth process. Here, the opening diameter is defined as the diameter of a circle having the same opening area (the equivalent diameter of a circle having the same opening area).

[0265] The mesh has 2 openings per mm 2 More than 400 pieces / mm 2 Preferably less than 10 pieces / mm 2 More than 200 pieces / mm 2 Less than 20 pieces / mm is more preferable. 2 More than 100 pieces / mm 2 More preferably, the number of openings is 2 / mm 2 If the number of openings is less than 400 / mm, the efficiency of mist generation tends to decrease significantly. 2 If the pressure exceeds this value, the droplets tend to condense after the mist is generated, hindering the formation of fine catalyst particles.

[0266] The thickness of the mesh is preferably 1 μm or more and 500 μm or less, more preferably 5 μm or more and 250 μm or less, and even more preferably 10 μm or more and 100 μm or less. If the thickness of the mesh is less than 1 μm, the durability tends to decrease with repeated use. On the other hand, if the thickness of the mesh is more than 500 μm, ultrasonic vibration cannot be efficiently applied, and mist generation tends to be inhibited.

[0267] The mesh may be made of, for example, stainless steel. The frequency of the horn vibrator 41a is preferably 50 kHz or more and 400 kHz or less, more preferably 70 kHz or more and 300 kHz or less, and even more preferably 100 kHz or more and 200 kHz or less. If the frequency of the horn vibrator is less than 50 kHz, the mist generation efficiency tends to decrease, which is not preferable. On the other hand, if the frequency of the horn vibrator exceeds 400 kHz, the mesh tends to deteriorate early, which is not preferable.

[0268] 20 includes a reaction tube 31 continuous with the reaction tube constituting the CNT growth section 21, and a mist generator 60b connected to the reaction tube 31. That is, the mist generating section 37b is connected to the CNT growth section 21.

[0269] The mist generator 60b includes a first container 47 that holds water 43, an oscillator 41b disposed at the bottom of the first container 47, and a second container 48 disposed inside the first container 47. At least a portion of the outer surface of the second container 48 is in contact with the water 43. The second container 48 contains a mist raw material liquid 38 inside. The second container is provided with a gas inlet 40 that introduces gas from the outside, and a connection part 45 that is connected to the reaction tube 31.

[0270] A carrier gas such as argon is introduced from the gas inlet 40. The introduction of the carrier gas can promote the supply of mist into the reaction tube 31. In addition, the flow rate of the carrier gas can be changed to adjust the flow rate of the gas in the CNT growth section and the CNT extension section.

[0271] The oscillator 41b vibrates to give ultrasonic vibration energy to the water. The ultrasonic vibration energy is concentrated on the surface of the mist raw material liquid 38, and the mist raw material liquid 38 is atomized by the vibration (cavitation effect) to become mist 39. The mist 39 is supplied into the reaction tube 31 through the connection part 45 together with the gas taken in from the gas inlet 40.

[0272] 21 includes a reaction tube 31 that is continuous with the reaction tube that constitutes the CNT growth section 21, and a mist generator 60c that is connected to the reaction tube 31. That is, the mist generating section 37c is connected to the CNT growth section 21.

[0273] The mist generating device 60c comprises a container 49 in which the mist raw material liquid 38 is stored, an air inlet 44 for introducing compressed air generated from a compressor (not shown) into the inside of the container 49, a nozzle portion 52 arranged continuously above the air inlet 44, a baffle 51 arranged above the nozzle portion 52, and piping 53 for bringing the mist raw material liquid 38 to the vicinity of the nozzle portion 52.

[0274] When the compressed air introduced from the air inlet 44 is discharged from the nozzle part 52, a negative pressure action is generated between the nozzle part 52 and the piping 53. Due to the negative pressure action, the mist raw material liquid 38 is sucked up to the upper part of the piping 53, collides with the baffle 51, and is atomized to become the mist 39. The mist 39 is supplied into the reaction tube 31 through the connection part 45.

[0275] The connection part 45 may be provided with a gas inlet 40 for introducing gas from the outside. A carrier gas such as argon is introduced from the gas inlet 40. The introduction of the carrier gas can promote the supply of mist into the reaction tube 31. In addition, the flow rate of the carrier gas can be changed to adjust the flow rate of the gas in the CNT growth part and the CNT extension part. <Carbon nanotube growth area> The carbon nanotube growing section 21 has a tubular shape made of, for example, a quartz tube. In the CNT growing section 21, the carbon nanotubes 2 are formed on the catalyst particles P using a liquid carbon source contained in the mist as a raw material.

[0276] The carbon nanotube growing portion 21 is placed in an electric furnace 28 and heated by a heater (not shown).

[0277] The temperature at which the mist is heated is preferably 800° C. or more and 1200° C. or less. That is, the internal temperature of the CNT growth section 21 is preferably 800° C. or more and 1200° C. or less. In order to maintain such a temperature, a heated carrier gas may be supplied from the gas inlet 40, or the mist may be heated in the CNT growth section 21.

[0278] <Carbon nanotube assembly> The carbon nanotube assembly portion 24 can have the same configuration as the carbon nanotube assembly portion described in the above embodiment 4-1, and therefore the description thereof will not be repeated.

[0279] <Other configurations> In addition to the above configuration, the CNT aggregated wire manufacturing apparatus 20c can include a magnetic field generating unit that generates a magnetic field and an electric field generating unit that generates an electric field, similar to the above embodiment 4-1. The magnetic field generating unit and the electric field generating unit can be configured in the same manner as the magnetic field generating unit and the electric field generating unit described in the above embodiment 4-1, and therefore the description thereof will not be repeated.

[0280] [Embodiment 5-1: Manufacturing method for carbon nanotube assembly wire bundle (1)] The manufacturing method of the carbon nanotube assembly wire bundle according to the embodiment 5-1 is the manufacturing method of the carbon nanotube assembly wire bundle according to the embodiment 2. The manufacturing method of the carbon nanotube assembly wire bundle according to the embodiment 5-1 can include a growing step (hereinafter also referred to as the growing step) of growing one or more carbon nanotubes from each of the plurality of catalyst particles by supplying a carbon-containing gas to the plurality of catalyst particles in a suspended state, an elongating step (hereinafter also referred to as the elongating step) of elongating the plurality of carbon nanotubes in a suspended state by applying a tensile force to the plurality of carbon nanotubes, an assembling step (hereinafter also referred to as the assembling step) of orienting and assembling the plurality of suspended carbon nanotubes in a direction along the flow of the carbon-containing gas to obtain a plurality of carbon nanotube assembly wires, and a bundling step (hereinafter also referred to as the bundling step) of orienting and bundling the plurality of carbon nanotube assembly wires in a direction along the longitudinal direction of the plurality of carbon nanotube assembly wires to obtain a carbon nanotube assembly wire bundle.

[0281] The growing step, the stretching step, and the gathering step in the manufacturing method (1) of the carbon nanotube aggregate wire bundle of embodiment 5-1 are the same as the growing step, the stretching step, and the gathering step in the manufacturing method (1) of the carbon nanotube aggregate wire described in embodiment 3-1, respectively, and therefore the description thereof will not be repeated.

[0282] <Bundling process> In the bundling step, a plurality of carbon nanotube assembly wires are oriented in a direction along the longitudinal direction of the plurality of carbon nanotube assembly wires and bundled together to obtain a carbon nanotube assembly wire bundle.

[0283] The bundling step can be carried out simultaneously with the assembly step. That is, in the assembly step, in parallel with the production of the CNT-assembled wire, the obtained CNT-assembled wires are oriented in the longitudinal direction and bundled to obtain a CNT-assembled wire bundle. In this case, the bundling step is carried out inside the CNT assembly section 24.

[0284] The bundling step can also be carried out independently after the assembly step. That is, the bundling step can be carried out after the CNT assembly wire is produced in the assembly step. In this case, it is preferable that the CNT bundle section is connected to and disposed downstream of the carbon-containing gas of the CNT assembly section 24.

[0285] The CNT bundle portion may be, for example, a honeycomb structure, a straight thin tube structure, or the like.

[0286] [Embodiment 5-2: Manufacturing method for carbon nanotube assembly wire bundle (2)] Another example of the manufacturing method of the carbon nanotube assembly wire bundle according to the embodiment 2 will be described in the embodiment 5-2. The manufacturing method of the carbon nanotube assembly wire bundle according to the embodiment 5-2 includes a mist generating step (hereinafter also referred to as a mist generating step) of generating a mist containing a plurality of catalyst particles and a liquid carbon source, a growing step (hereinafter also referred to as a growing step) of growing one or more carbon nanotubes from each of the plurality of catalyst particles by heating the mist, an assembling step (hereinafter also referred to as an assembling step) of orienting and assembling the plurality of carbon nanotubes in a direction along their longitudinal direction to obtain a carbon nanotube assembly wire, an elongating step (hereinafter also referred to as an elongating step) of elongating the plurality of carbon nanotubes by applying a tensile force to the plurality of carbon nanotubes in a suspended state, and a bundling step of orienting and bundling the plurality of carbon nanotube assembly wires in a direction along their longitudinal direction to obtain a carbon nanotube assembly wire bundle.

[0287] The mist generating step, the growing step, the elongating step, and the assembling step in the method for producing a carbon nanotube assembly wire bundle according to the embodiment 5-2 are respectively the same as those in the method for producing a carbon nanotube assembly wire according to the embodiment 3-2. Mist generating process, The growing step, the elongating step, and the assembling step are the same steps, and therefore the description thereof will not be repeated. Moreover, the bundling step is the same step as the bundling step in the method for manufacturing a carbon nanotube assembly wire bundle described in the above embodiment 5-1, and therefore the description thereof will not be repeated.

[0288] [Embodiment 6-1: Carbon nanotube assembly wire bundle manufacturing device (1)] A carbon nanotube assembly wire bundle manufacturing apparatus used for manufacturing a carbon nanotube assembly wire bundle according to the second embodiment will be described. The carbon nanotube assembly wire bundle manufacturing apparatus can include a tubular carbon nanotube growth section (hereinafter also referred to as a CNT growth section), a gas supply section that supplies a carbon-containing gas from one end of the CNT growth section to the CNT growth section, a catalyst supply section that supplies catalyst particles P into the CNT growth section, a carbon nanotube assembly section (hereinafter also referred to as a CNT assembly section) that is disposed on the other end side of the CNT growth section and orients and assembles a plurality of carbon nanotubes obtained in the CNT growth section in a direction along the flow of the carbon-containing gas, and a bundle section that orients and bundles a plurality of carbon nanotube assembly wires in a direction along the longitudinal direction of the plurality of carbon nanotube assembly wires to obtain a carbon nanotube assembly wire bundle. The CNT growth section, the CNT assembly section, the bundle section, and the catalyst supply section include a continuous reaction tube, and the CNTs, the CNT assembly wire, and the CNT assembly wire bundle are manufactured inside the reaction tube.

[0289] The CNT growth section, gas supply section, catalyst supply section, and CNT assembly section in the carbon nanotube assembly wire bundle manufacturing apparatus of embodiment 6-1 have the same configurations as the CNT growth section, gas supply section, catalyst supply section, and CNT assembly section in the carbon nanotube assembly wire manufacturing apparatus described in embodiment 4-1, respectively, and therefore their descriptions will not be repeated.

[0290] <Bundle section> In the bundle section, a plurality of CNT aggregate wires in a suspended state are aligned in the longitudinal direction and bundled together to form a carbon nanotube aggregate wire bundle.

[0291] The bundle section is made up of multiple carbon nanotube wires in a suspended state. Longitudinal direction of CNT strandAny structure can be used as long as the fibers can be oriented and assembled in the direction along the axis of the bundle. For example, the bundle portion can be made of a honeycomb structure, a straight capillary structure, or the like.

[0292] When the bundle portion is made of a honeycomb structure, the honeycomb structure is placed in the carbon nanotube assembly wire bundle manufacturing apparatus so that the longitudinal direction of the through holes is aligned with the flow of the carbon-containing gas.

[0293] When the bundle portion is made of a honeycomb structure, the configuration thereof can be the same as the honeycomb structure described in the above CNT aggregated wire manufacturing apparatus.

[0294] The bundle portion may have a structure that also serves as the carbon nanotube assembly portion, that is, the CNT assembly portion may have a function as the bundle portion.

[0295] The bundle portion may be a separate structure from the carbon nanotube assembly portion. In this case, the bundle portion is preferably connected to the downstream side of the CNT assembly portion 24 in the carbon-containing gas flow.

[0296] <Other configurations> The CNT-aggregated wire bundle manufacturing apparatus may include a magnetic field generating unit that generates a magnetic field in addition to the above configuration. The configuration may be the same as the magnetic field generating unit described in the above CNT-aggregated wire manufacturing apparatus.

[0297] The CNT-aggregated wire bundle manufacturing apparatus may include an electric field generating unit that generates an electric field in addition to the above configuration. The configuration may be the same as the electric field generating unit described in the above CNT-aggregated wire manufacturing apparatus.

[0298] [Embodiment 6-2: Carbon nanotube assembly wire bundle manufacturing device (2)] Another example of the carbon nanotube assembly wire bundle manufacturing apparatus used for manufacturing the carbon nanotube assembly wire bundle according to the second embodiment will be described in the embodiment 6-2. The carbon nanotube assembly wire bundle manufacturing apparatus according to the second embodiment may include a mist generating section that generates a mist containing a plurality of catalyst particles and a liquid carbon source, a tubular carbon nanotube growing section that is connected to the mist generating section and heats the mist to grow one or more carbon nanotubes from each of the plurality of catalyst particles, a carbon nanotube assembly section that is disposed on one end side of the carbon nanotube growing section and orients and aggregates the plurality of carbon nanotubes obtained in the carbon nanotube growing section in a direction along the longitudinal direction thereof to obtain a carbon nanotube assembly wire, and a bundle section that orients and bundles the plurality of carbon nanotube assembly wires in a direction along the longitudinal direction of the plurality of carbon nanotube assembly wires to obtain a carbon nanotube assembly wire bundle. The mist generating section, the CNT growing section, the CNT assembly section, and the bundle section include a continuous reaction tube, and the CNTs, the CNT assembly wire, and the CNT assembly wire bundle are manufactured inside the reaction tube.

[0299] The mist generating section, CNT growth section, and CNT assembly section in the carbon nanotube assembly wire bundle manufacturing apparatus of embodiment 6-2 have the same configuration as the mist generating section, CNT growth section, and CNT assembly section in the carbon nanotube assembly wire manufacturing apparatus described in embodiment 4-2 above, and therefore their description will not be repeated.

[0300] The bundle section in the carbon nanotube assembly wire bundle manufacturing apparatus according to embodiment 6-2 has the same configuration as the bundle section in the carbon nanotube assembly wire bundle manufacturing apparatus described in embodiment 6-1 above, and therefore description thereof will not be repeated.

[0301] [Embodiment 7: Carbon nanotube structure] <Carbon nanotube structure> Fig. 23 is an example of a transmission electron microscope (TEM) image of a carbon nanotube structure (hereinafter also referred to as a CNT structure) according to an embodiment of the present disclosure. As shown in Fig. 23, a carbon nanotube structure 4 according to this embodiment includes a carbon nanotube 2 and catalyst particles P attached to both ends of the carbon nanotube 2, and the catalyst particles P have a particle diameter of 0.6 nm or more and less than 30 nm.

[0302] (shape) The carbon nanotube structure has a shape in which catalyst particles are attached to both ends of the carbon nanotube. Here, catalyst particles attached to both ends of the carbon nanotube means (i) a state in which the catalyst particles are attached to both ends of the carbon nanotube with at least a part of them exposed to the outside of the carbon nanotube, (ii) a state in which the catalyst particles are attached to both ends of the carbon nanotube and completely embedded inside the carbon nanotube (see FIG. 23), or (iii) a state in which the catalyst particles are attached to one end of the carbon nanotube with at least a part of them exposed to the outside of the carbon nanotube and attached to the other end and completely embedded inside the carbon nanotube.

[0303] The shape of the carbon nanotube is not particularly limited, and may be either closed or open at the end. In addition, one or both ends of the carbon nanotube may have a cone-shaped graphene cone formed thereon.

[0304] The length of the carbon nanotube structure can be appropriately selected depending on the application. The length of the carbon nanotube structure is, for example, preferably 10 μm or more, more preferably 100 μm or more. In particular, a length of 100 μm or more is suitable from the viewpoint of producing a CNT assembly wire. The upper limit of the length of the carbon nanotube structure is not particularly limited, but from the viewpoint of production, it is preferably 600 mm or less. The length of the CNT structure can be measured by observation with a scanning electron microscope.

[0305] The diameter of the carbon nanotube structure is preferably 0.6 nm to 20 nm, more preferably 1 nm to 10 nm, and particularly preferably 1 nm to 10 nm, from the viewpoint of heat resistance under oxidizing conditions.

[0306] In this specification, the diameter of a carbon nanotube structure means the average outer diameter of the portion of a CNT structure to which no catalyst particles are attached. The average outer diameter of the portion of a CNT structure to which no catalyst particles are attached is obtained by directly observing the cross section of any two points of the CNT in the portion to which no catalyst particles are attached using a transmission electron microscope, measuring the outer diameter, which is the distance between the two most distant points on the circumference of the CNT, in the cross section, and calculating the average value of the obtained outer diameters.

[0307] (catalyst particles) The carbon nanotube structure has catalyst particles attached to both ends of the carbon nanotubes. The catalyst particles have a particle diameter of 0.6 nm or more and less than 30 nm. The catalyst particles are derived from the catalyst (ferrocene (Fe(C5H5)2), iron oxide powder (Fe2O3), etc.) used in the production of the CNT assembly wire. In the CNT structure according to this embodiment, the catalyst particles have a small particle diameter of less than 30 nm and are not coarsened, so that the catalyst particles do not affect the electrical conductivity properties of the CNTs. Therefore, the CNT structure can be elongated while maintaining the electrical conductivity inherent to the CNTs.

[0308] The particle diameter of the catalyst particles contained in the CNT structure can be measured by the following method. First, the carbon nanotube structure is observed at a magnification of 100,000 to 500,000 times using a transmission electron microscope (TEM). Next, in the TEM image, the outer diameter, which is the distance between the two most distant points on the circumference of each catalyst particle, is measured.

[0309] The catalyst particles contained in the CNT structure can contain at least one metal element selected from the group consisting of iron, nickel, cobalt, molybdenum, gold, silver, copper, yttrium, chromium, palladium, platinum, and tungsten. Here, the catalyst particles containing a metal element refers to both the case where the catalyst particles contain other elements (e.g., sulfur, oxygen, etc.) in addition to the metal element, and the case where the catalyst particles are composed only of the metal element.

[0310] The catalyst particles contained in the CNT structure preferably contain iron. In this case, the catalyst particles may be, for example, iron particles consisting of only iron, or iron sulfide (FeS, Fe2S), or iron oxide (Fe2O3, Fe3O4). The catalyst particles are more preferably iron particles consisting of iron. Using iron as a catalyst is suitable from the viewpoint of mass production of CNTs. Therefore, when the catalyst particles contain iron, it is possible to mass produce a long CNT assembly wire having a plurality of CNT structures.

[0311] The composition and content of the catalyst particles contained in the CNT structure can be confirmed by energy dispersive X-ray spectrometry (EDX). The total content of the catalyst particles in the CNT structure is preferably 0.01% to 50% by mass, more preferably 0.5% to 40%, and even more preferably 0.1% to 20%.

[0312] (D / G ratio) The carbon nanotubes in the carbon nanotube structure preferably have a D / G ratio, which is the ratio of the peak intensity of the G band to the peak intensity of the D band in Raman spectroscopy at a wavelength of 532 nm, of 0.1 or less, which allows the CNT structure to have high tensile strength and high electrical conductivity.

[0313] The method for measuring the D / G ratio is the same as that described in the first embodiment, and therefore the description thereof will not be repeated.

[0314] [Embodiment 8: Method for manufacturing a carbon nanotube structure] The method for manufacturing a carbon nanotube structure according to Embodiment 8 is the method for manufacturing a carbon nanotube structure according to Embodiment 7. The method for manufacturing a carbon nanotube structure according to Embodiment 8 includes a mist generation step of generating a mist containing catalyst particles and a liquid carbon source (hereinafter, also referred to as the mist generation step), and heating the mist in a flow of carrier gas while separating a plurality of catalyst particles in an adhered state to grow carbon nanotubes between the plurality of catalyst particles to obtain a CNT structure (hereinafter, also referred to as the step of obtaining a CNT structure).

[0315] As the method for manufacturing a carbon nanotube structure, for example, a carbon nanotube structure manufacturing apparatus 50 shown in FIG. 22 can be used.

[0316] The carbon nanotube structure manufacturing apparatus 50 can include a mist generation unit 37 that generates a mist 39 containing catalyst particles and a liquid carbon source, a gas supply unit 22 that supplies a carrier gas into the mist generation unit 37, and a tubular carbon nanotube growth unit (hereinafter, also referred to as the CNT growth unit) 21 that is connected to the mist generation unit 37.

[0317] <Mist Generation Step> Since the mist generation step is the same as the mist generation step in the method for manufacturing a CNT assembly wire in Embodiment 3-2 described above, the description thereof will not be repeated.

[0318] <Step of Obtaining a CNT Structure> In the step of obtaining a CNT structure, while heating the mist 39 in a flow of carrier gas, a plurality of catalyst particles in an adhered state are separated to grow carbon nanotubes between the plurality of catalyst particles to obtain a CNT structure. The step of obtaining a CNT structure is performed inside the CNT growth unit 21.

[0319] By heating the mist in the flow of the carrier gas, the catalyst particles in the mist that are in close contact with each other are separated, and at the same time, CNTs grow between the catalyst particles using the liquid carbon source contained in the mist as a raw material. In this embodiment, since the liquid carbon source contained in the mist is used as the carbon source for CNTs, there is no need to use the carbon-containing gas used in the above embodiment 3-1. This is an advantage in terms of simplifying the CNT manufacturing process and reducing costs.

[0320] The temperature at which the mist is heated is preferably 800°C or higher and 1200°C or lower. That is, the process of obtaining the CNT structure is preferably performed under temperature conditions of 800°C or higher and 1200°C or lower. If the temperature is lower than 800°C, the growth rate of the CNTs tends to be slow. On the other hand, if the temperature exceeds 1200°C, the content of impurity carbon tends to increase. Obtaining CNT structures The temperature condition of the process is more preferably 900°C or higher and 1150°C or lower, and further preferably 950°C or higher and 1050°C or lower.

[0321] The carrier gas supplied from the gas supply unit 22 may be, for example, argon, helium, hydrogen, nitrogen, neon, krypton, or the like.

[0322] The carrier gas supplied from the gas supply unit 22 passes through the mist generating unit 37 and reaches the inside of the CNT growth unit 21. The lower limit of the average flow velocity of the carrier gas in the CNT growth unit 21 is 0.05 cm / sec, preferably 0.10 cm / sec, and more preferably 0.20 cm / sec. On the other hand, the upper limit of the average flow velocity of the carrier gas in the CNT growth unit 21 is preferably 10.0 cm / sec, and more preferably 5.0 cm / sec. If the average flow velocity of the carrier gas in the CNT growth unit 21 does not meet the lower limit, the mist tends to condense and liquefy in the furnace tube. Conversely, if the average flow velocity of the carrier gas in the CNT growth unit 21 exceeds the upper limit, the carbon nanotubes tend to peel off from the catalyst particles P, stopping the growth of the carbon nanotubes, thereby inhibiting the formation of the carbon nanotubes.

[0323] The lower limit of the Reynolds number of the flow of the carrier gas supplied from the gas supply unit 22 in the CNT growth unit 21 is preferably 0.01, more preferably 0.05. On the other hand, the upper limit of the Reynolds number is 1000, preferably 100, more preferably 10. If the Reynolds number is less than the lower limit, the design of the device is excessively restricted, so that the carbon nanotube structure manufacturing device 50 may become unnecessarily expensive, and the manufacturing efficiency of the carbon nanotube structure may unnecessarily decrease. If the Reynolds number exceeds the upper limit, the flow of the carbon-containing gas may become turbulent, which may hinder the generation of carbon nanotubes on the catalyst particles P.

[0324] [Embodiment 9: Carbon nanotube structure manufacturing device] A carbon nanotube structure manufacturing apparatus used for manufacturing a carbon nanotube structure according to the seventh embodiment will be described with reference to Fig. 22. A carbon nanotube structure manufacturing apparatus 50 shown in Fig. 22 can include a mist generating unit 37 that generates a mist 39 containing catalyst particles and a liquid carbon source, a gas supply unit 22 that supplies a carrier gas into the mist generating unit 37, and a tubular carbon nanotube growing unit (hereinafter also referred to as a CNT growing unit) 21 connected to the mist generating unit 37.

[0325] <Mist generating area, CNT growing area> The mist generating section and the CNT growing section can have the same configuration as the mist generating section and the CNT growing section in the CNT aggregated wire manufacturing apparatus described in embodiment 4-2, respectively, and therefore the description thereof will not be repeated.

[0326] <Gas supply section> The gas supply unit 22 supplies a carrier gas into the mist generating unit 37. The gas supply unit 22 may include a gas cylinder (not shown) and a flow rate control valve (not shown). The carrier gas supplied from the gas supply unit 22 passes through the mist generating unit 37 and reaches the inside of the CNT growth unit 21.

[0327] The type of carrier gas supplied from gas supply unit 22, the average flow velocity within the CNT growth section, and the Reynolds number of the flow within the CNT growth section can be the same as those described in the manufacturing method of the CNT structure in embodiment 8 above, and therefore the description will not be repeated.

[0328] It is preferable that the gas supply unit 22 can repeatedly change the amount of carrier gas supplied to the CNT growth unit 21. This increases or decreases the flow rate of the carrier gas in the CNT growth unit 21, promoting separation of a plurality of aggregated catalyst particles, thereby increasing the number of carbon nanotube structures that can be obtained.

[0329] [Note] The present disclosure relates to a carbon nanotube assembly wire bundle including a plurality of carbon nanotube assembly wires according to the first embodiment, In the carbon nanotube assembly wire, the carbon nanotubes are aligned with an orientation degree of 0.9 or more and 1 or less, In the carbon nanotube assembly wire bundle, the carbon nanotube assembly wires are oriented with an orientation degree of 0.8 or more and 1 or less.

[0330] The carbon nanotube assembly wire bundle preferably includes an oriented region and an amorphous region. EXAMPLES

[0331] The present embodiment will be described in more detail with reference to examples, although the present embodiment is not limited to these examples.

[0332] [Study on carbon nanotube assembly wires (1)] <Preparation of carbon nanotube assembly wire manufacturing equipment> (device 1) As the apparatus 1, a carbon nanotube assembly wire manufacturing apparatus having the same configuration as the carbon nanotube assembly wire manufacturing apparatus shown in FIG. 14 was prepared. Specifically, the carbon nanotube growth section 21 and the carbon nanotube assembly section 24 were placed in an electric furnace 28. The CNT growth section was made of a quartz tube with an inner diameter of 20 mm and a length of 800 mm. As the carbon nanotube assembly section 24, a honeycomb structure made of ceramics was placed in the quartz tube continuous with the CNT growth section. The honeycomb structure had about 200 through holes per inch, and the cross-sectional area of ​​each through hole was 0.8 mm. 2 It is.

[0333] A catalyst supply unit 23 is disposed on the side of CNT growth unit 21 opposite to the side connected to CNT assembly unit 24. Catalyst supply unit 23 is made of a quartz tube with an inner diameter of 20 mm and a length of 200 mm, and is disposed continuous with the CNT growth unit. Ferrocene is disposed as a catalyst on catalyst holder 26 in catalyst supply unit 23. Catalyst supply unit 23 is heated by heater 25.

[0334] A gas supply unit 22 is disposed on the side of the catalyst supply unit 23 opposite to the side connected to the CNT growth unit 21 .

[0335] (device 2) As the apparatus 2, an apparatus having a configuration basically similar to that of the apparatus 1 was prepared. The difference from the apparatus 1 is that the carbon nanotube assembly section 24 is not arranged. That is, in this apparatus, the CNT assembly section is not arranged at the end opposite to the side connected to the catalyst supply section 23 of the CNT growth section 21.

[0336] <Preparation of carbon nanotube assembly> Carbon nanotube assembly wires of Sample 1 and Sample 2 were produced using the manufacturing equipment of Equipment 1 and Equipment 2, respectively. First, in each of Equipment 1 and Equipment 2, argon gas with an argon gas concentration of 100% by volume was supplied from the gas supply unit into the CNT growth unit at a flow rate of 1000cc / min (flow rate of 3.4cm / sec) for 50 minutes, while the temperature in the electric furnace was raised to 1000°C. Next, in addition to the argon gas, methane gas was supplied at a flow rate of 50cc / min (flow rate of 0.17cm / sec) and carbon disulfide (CS2) gas was supplied at a flow rate of 1cc / min (flow rate of 0.003cm / sec) for 120 minutes. The flow rate of the entire mixed gas (carbon-containing gas) containing argon gas, methane gas, and carbon disulfide was 3.6cm / sec.

[0337] By supplying the above argon gas, methane gas, and carbon disulfide gas, the catalyst was broken down and the catalyst particles were released into the CNT growth area. After that, CNTs grew in the CNT growth area.

[0338] In the apparatus 1, the CNTs were subsequently elongated and aggregated in the CNT aggregated portion, and a CNT aggregated wire was obtained. When the downstream side of the honeycomb structure constituting the CNT aggregated portion of the apparatus 1 was visually observed, it was confirmed that a carbon nanotube aggregated wire 1 (sample 1) formed by the aggregation of multiple CNTs was emitted from the through-holes of the honeycomb structure 29, as shown in FIG.

[0339] In device 2, the downstream side of the CNT growth section was observed with an SEM, and a CNT aggregated wire (sample 2) consisting of an aggregate of multiple CNTs was confirmed.

[0340] <Measurement of carbon nanotube assembly wire> (Orientation degree) The orientation degree was measured for the carbon nanotube aggregate wires of Sample 1 and Sample 2. The method for calculating the orientation degree was the same as that described in the first embodiment, and therefore the description thereof will not be repeated.

[0341] A TEM image of the CNT aggregate wire of Sample 1 is shown in Figure 2, and a Fourier transform image is shown in Figure 4. The relationship between the orientation angle and intensity of Sample 1 is shown in Figure 5.

[0342] The full width at half maximum of Sample 1 was 12° and the degree of orientation was 0.93. Sample 1 was confirmed to be an example.

[0343] The full width at half maximum of Sample 2 was 54° and the degree of orientation was 0.70. It was confirmed that Sample 2 was a comparative example.

[0344] (shape) The average length and average diameter were measured for the carbon nanotube aggregate wire of Sample 1. The method for measuring the average length and average diameter was the same as that described in the first embodiment, and therefore the description thereof will not be repeated.

[0345] The CNT aggregate wire of Sample 1 had a straight thread shape in which a plurality of carbon nanotubes were aggregated and oriented in the longitudinal direction, and had an average length of 10 cm and an average diameter of 50 μm.

[0346] (Catalyst-derived elements) The carbon nanotube assembly wire of Sample 1 was subjected to EDX analysis to identify catalyst-derived elements contained in the CNT assembly wire.

[0347] It was confirmed that sample 1 contained iron and sulfur. In addition, SEM observation and EDX analysis confirmed that iron and sulfur were dispersed in the longitudinal direction of the CNT aggregate wire.

[0348] [Study on carbon nanotube wire bundles] <Preparation of carbon nanotube assembly wire bundle manufacturing equipment> (device 3) As Apparatus 3, a carbon nanotube assembly wire bundle manufacturing apparatus having a configuration basically similar to that of Apparatus 1 was prepared. The difference from Apparatus 1 is that an orifice plate is installed on the outlet side of the honeycomb to converge the CNT assembly wire to one point.

[0349] (device 4) As the apparatus 4, an apparatus having a configuration basically similar to that of the apparatus 3 was prepared. The difference from the apparatus 3 is that the apparatus 4 is not equipped with a mechanism for converging the CNT aggregated wire.

[0350] <Fabrication of carbon nanotube wire bundles> Carbon nanotube assembly wire bundles of Sample 3 and Sample 4 were produced using the manufacturing equipment of Apparatus 3 and Apparatus 4, respectively. First, in each of Apparatus 3 and Apparatus 4, argon gas with an argon gas concentration of 100% by volume was supplied from the gas supply unit into the CNT growth unit at a flow rate of 1000cc / min (flow rate of 3.4cm / sec) for 50 minutes, while the temperature in the electric furnace was raised to 1000°C. Next, in addition to the argon gas, methane gas was supplied at a flow rate of 50cc / min (flow rate of 0.17cm / sec) and carbon disulfide (CS2) gas was supplied at a flow rate of 1cc / min (flow rate of 0.003cm / sec) for 120 minutes. The flow rate of the entire mixed gas (carbon-containing gas) containing argon gas, methane gas, and carbon disulfide was 3.6cm / sec.

[0351] By supplying the above argon gas, methane gas, and carbon disulfide gas, the catalyst was broken down and the catalyst particles were released into the CNT growth area. After that, CNTs grew in the CNT growth area.

[0352] In the apparatus 3, the CNTs were then elongated and aggregated in the CNT assembly portion to obtain a CNT assembly wire, which was then bundled to obtain a CNT assembly wire bundle. When the downstream side of the honeycomb structure constituting the CNT assembly portion of the apparatus 3 was visually observed, it was confirmed that a carbon nanotube assembly wire bundle (sample 3) formed by the aggregation of multiple CNT assembly wires was emitted from the through-holes of the honeycomb structure 29.

[0353] In the apparatus 4, the downstream side of the CNT growth portion was observed by SEM, and a CNT aggregate bundle (sample 4) in which a plurality of CNT aggregate wires were aggregated was confirmed.

[0354] <Measurement of carbon nanotube bundles> (degree of orientation) The orientation degree was measured for the carbon nanotube-assembled wire bundles of Sample 3 and Sample 4. The calculation method for the orientation degree of CNTs in the CNT-assembled wire is the same as the method described in the first embodiment, and therefore the description will not be repeated. The calculation method for the orientation degree of CNTs in the CNT-assembled wire bundle is the same as the method described in the second embodiment, and therefore the description will not be repeated.

[0355] In the CNT-aggregated wire bundle of sample 3, the orientation degree of the CNTs in the CNT-aggregated wire was 0.94, and the CNT-aggregated wire bundle included an orientation region in which the CNT-aggregated wire was oriented with an orientation degree of 0.93. In other words, it was confirmed that sample 3 corresponds to the example. In sample 3, the CNT-aggregated wire could be aggregated to form a CNT-aggregated wire bundle without impairing the orientation degree of the CNT-aggregated wire.

[0356] In the CNT-aggregated wire bundle of sample 4, the degree of orientation of CNTs in the CNT-aggregated wire was 0.93, and the maximum value of the degree of orientation of the CNT-aggregated wire in the entire measurement field of view was 0.76, and the CNT-aggregated wire bundle did not include an oriented region. In other words, it was confirmed that sample 4 corresponds to a comparative example.

[0357] (shape) The average length and the average diameter were measured for the carbon nanotube assembly wire bundle of Sample 3. The method for measuring the average length and the average diameter was the same as the method described in the second embodiment, and therefore the description thereof will not be repeated.

[0358] The CNT assembled wire bundle of sample 3 had a straight thread shape in which a plurality of carbon nanotube assembled wires were assembled and oriented in the longitudinal direction, and had an average length of 10 cm and an average diameter of 200 μm.

[0359] (Catalyst-derived elements) The CNT assembled wire included in the carbon nanotube assembled wire bundle of Sample 3 was subjected to EDX analysis to identify catalyst-derived elements included in the CNT assembled wire.

[0360] It was confirmed that sample 3 contained iron and sulfur. In addition, SEM observation and EDX analysis confirmed that iron and sulfur were dispersed in the longitudinal direction of the CNT aggregate wire.

[0361] (Ratio of oriented and amorphous regions) The volume ratio of the oriented region and the shapeless region was measured for the carbon nanotube assembly wire bundle of Sample 3. The method for measuring the volume ratio of the oriented region and the shapeless region was the same as the method described in the second embodiment, and therefore the description thereof will not be repeated.

[0362] The CNT assembly wire bundle of sample 3 had an oriented region of 80 volume % and an amorphous region of 20 volume %.

[0363] (Distance between carbon nanotube bundles) For the carbon nanotube aggregate wire bundle of sample 3, the minimum value of the distance between adjacent carbon nanotube aggregate wires in the orientation region was measured. The average diameter of the CNT aggregate wires constituting the CNT aggregate wire bundle was also measured. The method for measuring the minimum value of the distance between adjacent carbon nanotube aggregate wires in the orientation region and the average diameter of the CNT aggregate wire was the same as the method described in embodiment 2, and therefore the description thereof will not be repeated.

[0364] In Sample 3, the minimum distance between adjacent carbon nanotube aggregate wires in the oriented region was 300 nm, and the average diameter of the CNT aggregate wire was 25 nm. That is, it was confirmed that the minimum distance between adjacent carbon nanotube aggregate wires was 10 times or more the average diameter of the carbon nanotube aggregate wires.

[0365] (Angle between carbon nanotube bundles) The maximum angle between adjacent carbon nanotube aggregate wires in the orientation region was measured for the carbon nanotube aggregate wire bundle of Sample 3. The method for measuring the angle between adjacent carbon nanotube aggregate wires in the orientation region was the same as the method described in the second embodiment, and therefore the description thereof will not be repeated.

[0366] In Sample 3, the maximum angle between adjacent carbon nanotube aggregate lines in the oriented region was 9°. That is, it was confirmed that the maximum angle between adjacent carbon nanotube aggregate lines was 10° or less.

[0367] (elongation at break, breaking strength, Young's modulus) A breaking test was performed on the carbon nanotube assembly wire bundle of sample 3 to measure the breaking elongation, breaking strength, and Young's modulus. The breaking test method was the same as that described in the second embodiment, and therefore the description will not be repeated. The results are shown in the graph of FIG.

[0368] In the graph of Fig. 27, the horizontal axis (X axis) indicates elongation at break (%) and the vertical axis (Y axis) indicates breaking strength (GPa). As shown in Fig. 27, it was confirmed that the CNT assembly wire bundle of sample 3 had an elongation at break of 0.1%, a breaking strength of 7 GPa, and a Young's modulus of 1100 GPa.

[0369] (First metal content) The total content of the first metal element was measured by EDX for the carbon nanotube assembly wire bundle of Sample 3. The total content of the first metal element in the CNT assembly wire bundle of Sample 3 was 10 mass %.

[0370] [Study on carbon nanotube assembly wires (2)] <Preparation of carbon nanotube assembly wire manufacturing equipment> (device 5) As the apparatus 5, a carbon nanotube assembly wire manufacturing apparatus having the same configuration as the carbon nanotube assembly wire manufacturing apparatus shown in FIG. 18 was prepared. Specifically, the carbon nanotube growth section 21 and the carbon nanotube assembly section 24 were placed in an electric furnace 28. The CNT growth section was made of a quartz tube with an inner diameter of 25 mm and a length of 50 mm. As the carbon nanotube assembly section 24, a honeycomb structure made of ceramics was placed in the quartz tube continuous with the CNT growth section. The honeycomb structure had about 200 through holes per inch, and the cross-sectional area of ​​each through hole was 0.8 mm. 2 It is.

[0371] A mist generating section 37 is disposed on the side of the CNT growth section 21 opposite to the side where the CNT assembly section 24 is disposed. The mist generating section 37 has a configuration similar to that of the mist generating section 37a shown in FIG. 19. The mist generating section 37a includes a quartz tube having an inner diameter of 25 mm and a length of 200 mm disposed in continuity with the CNT growth section 21, and a mist generating device 60a disposed in connection with the quartz tube. A gas inlet 40 is provided at a connection section 45 of the mist generating device 60a. The carrier gas supplied from the gas supply section 22 to the gas inlet 40 passes through the mist generating section 37a and reaches the inside of the CNT growth section 21.

[0372] The mist generator 60a has a horn vibrator 41a and a mesh 42 arranged opposite to the vibration surface of the horn vibrator 41a. The mesh is made of a metal plate with a thickness of 10 μm, and the openings are circular with a diameter of 20 μm, and the number of openings is 100 per mm. 2 The frequency of the horn transducer is 110 kHz.

[0373] <Preparation of carbon nanotube assembly> Using the manufacturing apparatus 5, carbon nanotube assembly wires of Sample 5-1 and Sample 5-2 were produced.

[0374] For sample 5-1, the mist raw material solution was prepared by dispersing ferrocene in ethanol. The concentration of ferrocene in the mist raw material solution was 1% by weight.

[0375] For sample 5-2, iron oxide powder (Fe2O3, average particle size 70 nm) was dispersed in ethanol to prepare the mist raw material liquid. The concentration of iron oxide powder in the mist raw material liquid was 2% by weight.

[0376] Using the mist raw material liquid, mist was generated by the mist generator 60a, and argon gas with an argon gas concentration of 100% by volume was supplied from the gas supply unit to the CNT growth unit at a flow rate of 1000cc / min (flow rate of 3.4cm / sec) for 50 minutes, while the temperature in the electric furnace was raised to 1000°C. The average particle diameter of the mist was 35μm. As a result, CNTs grew in the CNT growth unit.

[0377] In both Sample 5-1 and Sample 5-2, the CNTs were subsequently elongated and aggregated in the CNT aggregated portion, and a CNT aggregated wire was obtained. When the downstream side of the honeycomb structure constituting the CNT aggregated portion of the device 5 was visually observed, it was confirmed that the carbon nanotube aggregated wire 1 formed by the aggregation of multiple CNTs was emitted from the through-holes of the honeycomb structure 29 in both Sample 5-1 and Sample 5-2. An image of the carbon nanotube aggregated wire obtained in Sample 5-2 is shown in FIG. 25.

[0378] <Measurement of carbon nanotube assembly wire> (Orientation degree) The orientation degree was measured for the carbon nanotube aggregate wires of Sample 5-1 and Sample 5-2. The method for calculating the orientation degree was the same as that described in the first embodiment, and therefore the description thereof will not be repeated.

[0379] The full width at half maximum of Sample 5-1 was 12°, and the degree of orientation was 0.93. It was confirmed that Sample 5-1 corresponds to the embodiment.

[0380] The full width at half maximum of sample 5-2 was 14°, and the degree of orientation was 0.92. It was confirmed that sample 5-2 corresponds to the example.

[0381] (shape) The average length and the average diameter were measured for the carbon nanotube aggregate wires of Sample 5-1 and Sample 5-2. The method for measuring the average length and the average diameter was the same as that described in the first embodiment, and therefore the description thereof will not be repeated.

[0382] The CNT aggregate wire of sample 5-1 had a straight thread shape in which a plurality of carbon nanotubes were aggregated and oriented in the longitudinal direction, and had an average length of 10 cm and an average diameter of 55 μm.

[0383] The CNT aggregate wire of sample 5-2 had a straight thread shape in which a plurality of carbon nanotubes were aggregated and oriented in the longitudinal direction, and had an average length of 15 cm and an average diameter of 60 μm.

[0384] When the carbon nanotube assembly wires of Samples 5-1 and 5-2 were observed by TEM, it was confirmed that catalyst particles were attached to one or both ends of each of the carbon nanotubes, i.e., the carbon nanotube assembly wires of Samples 5-1 and 5-2 contained carbon nanotube structures.

[0385] (catalyst particles) The carbon nanotube aggregate wires of Sample 5-1 and Sample 5-2 were subjected to EDX analysis to identify the composition of the catalyst particles contained in the CNT aggregate wire.

[0386] It was confirmed that iron particles, which are catalytic particles, were contained in the carbon nanotube assembly wires of Samples 5-1 and 5-2. In addition, SEM observation and EDX analysis confirmed that the iron particles were dispersed in the longitudinal direction of the CNT assembly wire.

[0387] Furthermore, when Sample 5-2 was observed with an SEM, it was confirmed that the iron particles were approximately spherical and had a substantially uniform particle size, as shown in FIG.

[0388] The average particle diameter of the catalyst particles was measured for the carbon nanotube aggregate wires of Sample 5-1 and Sample 5-2. The method for measuring the average particle diameter of the catalyst particles was the same as the method described in the first embodiment, and therefore the description thereof will not be repeated.

[0389] In sample 5-1, the average particle size of the catalyst particles was 15 nm. In sample 5-2, the average particle diameter of the catalyst particles was 16 nm. The particle size distribution of the catalyst particles in the carbon nanotube aggregate wire obtained in sample 5-2 is shown in Figure 26. In Figure 26, the horizontal axis (X axis) represents the particle diameter (nm) and the vertical axis (Y axis) represents the number (counts). From FIG. 26, it was confirmed that in the carbon nanotube aggregate wire obtained in Sample 5-2, the particle diameter of the catalyst particles was 5 nm or more and 21 nm or less.

[0390] Although the embodiments and examples of the present disclosure have been described above, it is intended from the outset that the configurations of the above-described embodiments and examples may be appropriately combined or modified in various ways.

[0391] The embodiments and examples disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is indicated by the claims, not by the embodiments and examples described above, and is intended to include the meaning equivalent to the claims and all modifications within the scope. [Explanation of symbols]

[0392] 1, 1a, 1b, 1c, 1d carbon nanotube assembly wire, 2 carbon nanotube, 3 carbon nanotube assembly wire bundle, 20, 20a, 20b, 20c CNT assembly wire manufacturing apparatus, 21 CNT growth section, 22 gas supply section, 23 catalyst supply section, 24, 24a carbon nanotube assembly section, 25 heater, 26 catalyst holder, 27 catalyst, 28 electric furnace, 29 honeycomb structure, 30 CNT extension section, 31 reaction tube, 32 magnetic field lines, 33 + electrode, 34 - electrode, 35 orientation region, 36 amorphous region, 37 mist generation section, 38 mist raw material liquid, 39 mist, 40 gas inlet, 41a horn vibrator, 41b vibrator, 42 mesh, 43 water, 44 air inlet, 45 connection section, 47 first container, 48 Second vessel, 49 vessel, 50 CNT structure manufacturing device, 51 baffle, 52 nozzle portion, 53 piping, 55 electric wire, 60, 60a, 60b, 60c mist generating device, T tube portion, C cone portion, P catalyst particle.

Claims

1. A carbon nanotube assembly wire bundle including a plurality of carbon nanotube assembly wires, the carbon nanotube assembly wire includes a plurality of carbon nanotubes; In the carbon nanotube assembly wire, the carbon nanotubes are aligned with an orientation degree of 0.9 or more and 1 or less, the carbon nanotube assembly wire has catalyst particles; The catalyst particles have an average particle size of 0.6 nm or more and less than 30 nm, At least a portion of the carbon nanotubes have the catalyst particles attached to one or both ends of a tube portion of the carbon nanotube, The catalyst particles contain at least one metal element selected from the group consisting of iron, nickel, cobalt, molybdenum, gold, silver, copper, yttrium, chromium, palladium, platinum, and tungsten, the metal element contained in the catalyst particle is dispersed in the longitudinal direction of the carbon nanotube assembly wire, the carbon nanotube assembly wire bundle includes an orientation region in which the carbon nanotube assembly wire is oriented with an orientation degree of 0.8 to 1, a minimum distance between adjacent carbon nanotube aggregate wires in at least a portion of the orientation region is 10 times or more an average diameter of the carbon nanotube aggregate wires.

2. A carbon nanotube assembly wire bundle including a plurality of carbon nanotube assembly wires, the carbon nanotube assembly wire includes a plurality of carbon nanotubes; In the carbon nanotube assembly wire, the carbon nanotubes are aligned with an orientation degree of 0.9 or more and 1 or less, the carbon nanotube assembly wire has catalyst particles; The catalyst particles have an average particle size of 0.6 nm or more and less than 30 nm, At least a portion of the carbon nanotubes have the catalyst particles attached to one or both ends of a tube portion of the carbon nanotube, The catalyst particles contain at least one metal element selected from the group consisting of iron, nickel, cobalt, molybdenum, gold, silver, copper, yttrium, chromium, palladium, platinum, and tungsten, the metal element contained in the catalyst particle is dispersed in the longitudinal direction of the carbon nanotube assembly wire, the carbon nanotube assembly wire bundle includes an orientation region in which the carbon nanotube assembly wire is oriented with an orientation degree of 0.8 to 1, The carbon nanotube assembly wire bundle has an elongation at break of 0.1% or more and a breaking strength of 1 GPa or more.

3. 3 . The carbon nanotube assembly wire bundle according to claim 1 , wherein the catalyst particles are not unevenly distributed in a longitudinal direction of the carbon nanotube assembly wire. 4 .

4. The carbon nanotube assembly wire bundle according to claim 3 , wherein the catalyst particles include iron.

5. the carbon nanotube assembly contains elemental sulfur; The carbon nanotube assembly wire bundle according to claim 1 , wherein the sulfur element is dispersed in a longitudinal direction of the carbon nanotube assembly wire.

6. 6. The carbon nanotube assembly wire bundle according to claim 1, wherein the carbon nanotube assembly wire bundle includes the orientation region and an amorphous region in which an orientation degree of the carbon nanotube assembly wire is equal to or greater than 0 and less than 0.

8.

7. 3 . The carbon nanotube assembly wire bundle according to claim 2 , wherein in at least a portion of the orientation region, a minimum distance between adjacent carbon nanotube assembly wires is 10 times or more an average diameter of the carbon nanotube assembly wires.

8. 2. The carbon nanotube assembly wire bundle according to claim 1, wherein the carbon nanotube assembly wire bundle has an elongation at break of 0.1% or more and a breaking strength of 1 GPa or more.

9. The carbon nanotube assembly wire bundle according to claim 1 , wherein the carbon nanotube assembly wire bundle has a Young's modulus of 10 GPa or more.

10. 10. The carbon nanotube assembly wire bundle according to claim 1, wherein the carbon nanotube assembly wire bundle contains a total of 10 mass% or less of at least one first element selected from the group consisting of iron, sulfur, nickel, cobalt, molybdenum, gold, silver, copper, yttrium, chromium, palladium, platinum, and tungsten.

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