JP2014001493A - Aggregate of hollow carbon microfiber and method of manufacturing aggregate of hollow carbon microfiber - Google Patents

Aggregate of hollow carbon microfiber and method of manufacturing aggregate of hollow carbon microfiber Download PDF

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JP2014001493A
JP2014001493A JP2013183136A JP2013183136A JP2014001493A JP 2014001493 A JP2014001493 A JP 2014001493A JP 2013183136 A JP2013183136 A JP 2013183136A JP 2013183136 A JP2013183136 A JP 2013183136A JP 2014001493 A JP2014001493 A JP 2014001493A
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catalyst
aggregate
carbon fibers
metal
hollow carbon
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JP5708738B2 (en
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Yoshiro Sasao
義郎 笹尾
Emi Miura
恵美 三浦
Yutaka Fukuyama
裕 福山
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Mitsubishi Chemicals Corp
三菱化学株式会社
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Abstract

PROBLEM TO BE SOLVED: To provide an aggregate of carbon fiber, easily dispersed into a resin and improving electroconductivity of the resin.SOLUTION: In the aggregate of carbon fiber, dispersion in the resin becomes easy and electroconductivity of the resin containing the aggregate is improved by intertwining and aggregating bundles which are provided by aggregating oriented hollow carbon microfiber.

Description

  The present invention relates to an aggregate of fine hollow carbon fibers characterized in that bundles of fine hollow carbon fibers having orientation are gathered and aggregated.

  A fine carbon fiber having a diameter of 1 μm or less (hereinafter referred to as “carbon fiber” as appropriate) generally called carbon nanofiber or carbon nanotube is a filler that is mixed with a resin and imparts characteristics such as conductivity and strength. Various studies have been made. Such carbon fibers have heretofore been produced mainly by an arc discharge method, a laser evaporation method, a chemical vapor deposition method (CVD method) using a catalyst, or the like.

  Of these, the arc discharge method and the laser evaporation method require a vacuum device, a high-voltage, high-current power source, etc., which is expensive and requires a large-scale device that requires careful handling. In addition, the amount of carbon fiber produced There was a problem that there were few. Furthermore, the carbon fibers obtained by these methods are said to be relatively easy to obtain a highly crystalline carbon fiber, but graphite, amorphous carbon, fullerenes, etc. that are different from the fiber shape in the actual recovered material There was also a problem of containing a lot of impurities (Non-patent Document 1).

  In response to such problems, for example, a method of obtaining carbon fibers by pyrolyzing a raw material gas such as hydrocarbon or carbon monoxide on a catalytic metal (vapor phase growth method) is compared with the arc discharge method or laser evaporation method. Thus, there is an advantage that carbon fibers with less impurities can be obtained efficiently. In addition, a continuous reaction is possible by using a raw material in a gaseous state, and an inexpensive gas such as a hydrocarbon or carbon monoxide can be used as a raw material gas, which can be said to be a technique suitable for mass production of carbon fibers.

  Catalysts used in the vapor phase growth method (vapor phase growth carbon fiber production catalyst), for example, support particles such as silica, alumina, magnesia, zeolite, etc., carry fine particles of transition metal such as iron, cobalt, nickel, etc. Have been proposed. Since these catalysts generally have catalytic metals as oxides, carbon oxides are produced after reducing and activating the oxides in a reducing atmosphere with hydrogen, ammonia, etc. It is used for “deposition reaction”.

  When carbon fibers are vapor-phase-grown using the particulate catalyst thus produced, the carbon fibers are twisted and grow in a state where they are intertwined with each other. In general, it is known that conductivity can be imparted to an insulating resin by dispersing carbon fibers in the resin, but the entangled aggregates of carbon fibers obtained in this way are dispersed in the resin. Unfortunately, as a result, in order to obtain the desired conductivity, a large amount of carbon fiber has to be mixed. In addition, when a large amount of entangled aggregates of carbon fibers having poor dispersibility is mixed in the resin, there is a problem in that the strength of the resin is deteriorated.

  Further, in order to improve the dispersibility of the carbon fibers that have been tightly aggregated in this way, there has been proposed a method of miniaturization by post-treatment such as pulverization (Patent Document 1). However, the pulverization treatment may lead to an increase in cost and cutting of carbon fibers.

  On the other hand, if the carbon fibers are independent one by one or if a plurality of carbon fibers are gathered together to form a bundle, the dispersibility in the resin is good, and the conductivity is excellent with a small amount of dispersion. It has been introduced that a molded resin product can be supplied (Patent Document 2).

  On the other hand, as a conventional method for producing carbon fibers assembled in a bundle by a vapor phase growth method, there is a method based on a base method. That is, the catalyst is attached to the surface of the substrate by sputtering or the like, and the carbon fiber is grown linearly from the surface of the substrate. An example in which a carbon nanotube is manufactured by forming a tube wall of one or two layers of carbon fiber having a length of 2.5 mm by such a base method is disclosed (Non-patent Document 2). Similarly, an embodiment in which a catalyst component is patterned and applied to a silicon or quartz substrate is also disclosed (Patent Document 3).

Japanese Patent No. 2863192 JP 2004-230690 A Special Table 2002-530805 gazette

Nature Volume 354 November 7 (1991) Science Vol.306, November 19 (2004)

  As a technique for producing a carbon fiber having an orientation and assembled in a bundle, the base methods described in Patent Document 3 and Non-Patent Document 2 are excellent techniques, but this method is a growth point. The area of the catalyst is absolutely small, and the number of carbon fibers that grow on that basis is small, making it unsuitable for mass production.

  A vapor phase growth method using a fine particle catalyst is excellent in carbon fiber production efficiency. However, it is difficult to grow a carbon fiber while having orientation with a fine particle catalyst. Further, as described above, the carbon fiber aggregates are usually twisted and intertwined, and therefore cannot be aggregates of carbon fibers aggregated in a bundle.

  In other words, conventionally, a technique for efficiently producing an aggregate of carbon fibers in which multi-layered carbon fibers having an alignment with a uniform wire diameter and length are assembled in a bundle using a fine particle powder catalyst has been developed. unknown.

  This invention is made | formed in view of the said actual condition, Comprising: While disperse | distributing to resin, it provides the aggregate | assembly of the carbon fiber which the electroconductivity in the said resin improves compared with conventional carbon fiber. For the purpose.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors use an aggregate in which bundles of fine hollow carbon fibers having orientations are entangled and aggregated, so that dispersion into a resin is easy. In addition, the present inventors have found that it is possible to provide an aggregate of carbon fibers in which the conductivity of the resin containing the aggregate is improved as compared with conventional carbon fibers, and the present invention has been completed.

  That is, the gist of the present invention resides in an aggregate of fine hollow carbon fibers, in which bundles of fine hollow carbon fibers having orientation are gathered and aggregated (claim 1).

  At this time, an image obtained by cutting out a 30,000-fold image observed with a scanning electron microscope with 512 × 512 pixels is subjected to a fast Fourier transform (FFT) process, and the FFT intensity at the highest anisotropy angle is obtained in all directions. Of the values divided by the integrated value of the intensity, the intensity ratio at an image wavelength of 0.05 μm is preferably 0.2 or more and 0.5 or less (claim 2).

  Furthermore, it is preferable that the value obtained by dividing the intensity ratio in the 30,000 times image having a wavelength of 0.05 μm by the intensity ratio in the 300 times image having a wavelength of 5 μm is 1.5 or more.

Moreover, in the photograph observed with the scanning electron microscope, the number of the fine hollow carbon fibers included in 50% or more of the 100 bundles that are not the same bundle is 10 or more. The number is preferably 10 6 or less (claim 4).

  At this time, it is preferable that the average value of the outer diameter of the carbon fiber observed with a transmission electron microscope is 3 nm or more and 35 nm or less.

  Furthermore, the carbon fiber preferably has a multilayer structure.

Moreover, it is preferable that the length of the carbon fiber measured by a scanning electron microscope is not less than 10 times and not more than 10 6 times the outer diameter of the carbon fiber (Claim 7).

  The aggregate is preferably manufactured by a vapor deposition method.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the aggregate | assembly of the carbon fiber which the dispersion | distribution to resin is easy and the electroconductivity of resin containing an aggregate | assembly improves compared with a conventional carbon fiber.

(A) is a figure which expands and shows typically the mode near the catalyst in an example of the aggregate of the present invention, and (b) expands the mode near the catalyst in an example of the conventional carbon fiber aggregate. It is a figure shown typically. It is a drawing substitute photograph which shows the SEM photograph of catalyst A, (a) shows a photograph taken at 20,000 times, (b) shows a photograph taken at 10000 times, and (c) shows a photograph taken at 5,000 times. Show. It is a drawing substitute photograph showing an SEM photograph of catalyst B, (a) shows a photograph taken at 20,000 times, (b) shows a photograph taken at 10000 times, and (c) shows a photograph taken at 5,000 times. Show. It is drawing substitute photograph which shows the SEM photograph of catalyst C, (a) shows the photograph image | photographed by 30000 times, (b) shows the photograph image | photographed by 10000 times, (c) shows the photograph image | photographed by 3000 times. Show. It is a drawing substitute photograph which shows the SEM photograph of the carbon fiber of Example 1, (a), (b), (c), (d) and (e) are 300 times, 1000 times, 3000 times, and 10000 times, respectively. And photographs taken at 30000 times. It is a drawing substitute photograph which shows the SEM photograph of the carbon fiber of the comparative example 1, (a), (b), (c) and (d) are photographs taken at 300 times, 1000 times, 10000 times and 30000 times, respectively. Indicates. It is a drawing substitute photograph which shows the SEM photograph of the carbon fiber of the comparative example 2, (a), (b), (c) and (d) were image | photographed by 2000 times, 5000 times, 10000 times, and 30000 times, respectively. Show photos.

  Hereinafter, embodiments of the present invention will be described in detail. However, the description of the constituent elements described below is an example of the embodiments of the present invention, and the present invention can be arbitrarily changed without departing from the gist thereof. Can be implemented.

[1. Aggregate of the present invention]
An aggregate of fine hollow carbon fibers according to the present invention (hereinafter referred to as “the aggregate of the present invention” as appropriate) is a fine hollow carbon fiber having orientation (hereinafter referred to as “carbon fiber of the present invention” as appropriate). ) Are gathered together (hereinafter referred to as “the bundle of the present invention” as appropriate) and are entangled and aggregated.

  Here, the outline of the difference between the aggregate of the present invention and the conventional aggregate of carbon fibers will be described with reference to FIG. FIG. 1A is a diagram schematically showing an enlarged view of the vicinity of the catalyst in an example of the aggregate of the present invention, and FIG. 1B shows the state of the vicinity of the catalyst in an example of a conventional carbon fiber aggregate. It is a figure which expands and shows typically. As shown in FIG. 1 (a), in the aggregate of the present invention, carbon fibers grow while having orientation with the metal present on the plane of the catalyst of the present invention as a nucleus, and the carbon fibers are bundled while growing. Configure. Then, the bundles gather to form the aggregate of the present invention. On the other hand, in the conventional aggregate of carbon fibers, as shown in FIG. 1 (b), since the catalyst does not have a flat surface, the carbon fibers grow without orientation, and as a result, the carbon fibers are bundled. Without being formed, they are entangled and aggregated in a dumpling shape as shown in the figure.

[1-1. Carbon fiber of the present invention]
[1-1-1. Carbon fiber structure]
The carbon fiber of the present invention is a fiber composed of carbon. Moreover, the hollow part is normally formed continuously in the inside of the carbon fiber of this invention. For this reason, the carbon fiber of the present invention usually has a tubular shape, and has a configuration similar to what is called a “carbon nanotube”.
However, the hollow part formed inside the carbon fiber of the present invention is not necessarily continuous, and may be two or more chambers separated by one or two or more wall parts. Furthermore, there may be a portion where the hollow portion is not formed.

[1-1-2. Outer diameter]
Based on a photograph observed with a transmission electron microscope (hereinafter referred to as “TEM” as appropriate), the outer diameter of any 100 carbon fibers was measured, and the average value was determined as the outer diameter of the carbon fiber of the present invention. To do. The outer diameter of the carbon fiber of the present invention measured according to this method is usually 3 nm or more, preferably 5 nm or more, and particularly preferably 8 nm or more. Further, the upper limit is usually 35 nm or less, preferably 25 nm or less, particularly preferably 20 nm or less.

  Of the 100 carbon fibers measured, preferably 50 or more, more preferably 70 or more, particularly preferably 80 or more, preferably 3 nm or more, more preferably 5 nm or more, and particularly preferably 8 nm or more. In addition, the upper limit thereof is preferably 35 nm or less, more preferably 25 nm or less, and particularly preferably 20 nm or less.

  Further, among these 100 carbon fibers measured, 50 or more are preferably 8 nm or more and 20 nm or less, 70 or more are more preferably 5 nm or more and 25 nm or less, and 80 or more are more preferable. It is particularly preferable that the thickness is 3 nm or more and 35 nm or less.

  If the outer diameter is too short, when the aggregate of the present invention is blended with a resin, the ability to disperse in the resin is low, and therefore the conductivity may be inferior. In addition, if the outer diameter is too long, the weight per one becomes heavy, and the amount of carbon fiber per weight decreases. Therefore, in order to develop high conductivity when contained in the resin, a large amount of assembly The body may need to be included. Note that TEM photography can be performed using, for example, a transmission electron microscope JEM-1230 (manufactured by JEOL Ltd.). The applied voltage at the time of measurement is, for example, 120 kV.

[1-1-3. Inner diameter]
Based on the photograph observed by TEM, the internal diameter of arbitrary 100 carbon fiber is measured, and let the average value be an internal diameter of the carbon fiber of this invention. The inner diameter of the carbon fiber of the present invention measured according to this method is usually 2 nm or more, particularly preferably 3 nm or more. Further, the upper limit is usually 30 nm or less, preferably 25 nm or less, particularly preferably 20 nm or less. If the inner diameter is too short, the fibers may be bent and the orientation may not be obtained. On the other hand, if the inner diameter is too long, the fine fibers themselves may become too thick and it may be difficult to exhibit the performance according to the desired application. Note that TEM photography can be performed using, for example, a transmission electron microscope JEM-1230 (manufactured by JEOL Ltd.). The applied voltage at the time of measurement is, for example, 120 kV.

[1-1-4. Number of layers]
Based on the photograph observed by TEM, the number of layers of arbitrary 100 carbon fibers is measured, and the average value is defined as the number of layers of carbon fibers of the present invention. The carbon fiber of the present invention measured according to this method preferably has a multilayer structure. Further, the shape is preferably concentric. Specifically, it is preferably 3 layers or more, more preferably 4 layers or more, and particularly preferably 5 layers or more. The upper limit is preferably 30 layers or less, more preferably 25 layers or less, and particularly preferably 20 layers or less. If the carbon fiber is less than 3 layers, it may not be a multilayer structure fiber and may have poor resin dispersibility. If the number of layers is too large, the fiber diameter becomes too thick and the fiber itself loses its flexibility and is desired. There is a possibility that performance cannot be demonstrated. The TEM photography can be performed using, for example, a transmission electron microscope HR-TEM / H9000UHR (manufactured by JEOL Ltd.).

[1-1-5. Ratio of length to outer diameter]
The length of the carbon fiber of the present invention measured by a scanning electron microscope (hereinafter referred to as “SEM” as appropriate) is usually 10 times or more, preferably 100 times or more, relative to the outer diameter of the carbon fiber. More preferably, it is 1000 times or more. The upper limit is usually 10 6 times or less. If the length is too short, it may be inappropriate for constructing a conductive network, and if it is too long, it may easily cause entanglement of fibers, conversely causing a decrease in dispersion and making it difficult to construct the conductive network. is there.

[1-2. Bundle of the present invention]
[1-2-1. Overview]
The bundle of the present invention is a bundle in which fine hollow carbon fibers having orientation are gathered together. That is, the carbon fibers are arranged along a certain direction, and the aligned carbon fibers are integrated to form a bundle. This bundle is configured so that fibers gather together to form a yarn, and it cannot be easily broken into carbon fibers. Therefore, the physical properties and the like of the aggregate of the present invention can be easily controlled by controlling the bundle itself without controlling each carbon fiber.

[1-2-2. Number of carbon fibers included]
In a photograph observed with an SEM, when selecting an arbitrary 100 bundles that are not the same bundle and measuring the outer diameter of the bundle, and calculating the number of the bundles, it is usually 50% or more of the bundle of the present invention, preferably The number of carbon fibers contained in a bundle of 80% or more is usually 10 or more, preferably 30 or more, more preferably 50 or more. The number is usually 10 6 or less, preferably 10 5 or less, more preferably 10 4 or less. If the number is too small, it may not be suitable for the purpose of the present invention, and if the number is too large, it is difficult to produce using a powdered catalyst, and the dispersibility is increased because the bundle diameter becomes long. May be reduced.

[1-2-3. The bulk density]
The bulk density of the bundle of the present invention is arbitrary as long as the aggregate of the present invention is obtained. However, a preferred range of the bulk density of the bundle, usually 0.0001 g / cm 3 or more, preferably 0.005 g / cm 3 or more, more preferably 0.01 g / cm 3 or more. Also, it is usually 1 g / cm 3 or less, preferably 0.8 g / cm 3 or less, more preferably 0.5 g / cm 3 or less. If the bulk density is too small, handling may be difficult and the resin may not be kneaded well, and if it is too large, it may be difficult to disperse in the resin due to strong aggregation.

  Here, the bulk density can be measured by any method. For example, after slowly pouring a sample into a container of a certain volume, leveling with a spatula and measuring the weight twice, the bulk density can be calculated based on the measurement result. As a more specific measuring method, JIS K6219 was used.

[1-2-4. BET specific surface area]
The BET specific surface area of the bundle of the present invention is arbitrary as long as the aggregate of the present invention is obtained. However, the preferable range is usually 100 m 2 / g or more, preferably 200 m 2 / g or more. Moreover, the upper limit is 400 m < 2 > / g or less normally, Preferably it is 350 m < 2 > / g or less. When the specific surface area is too small, the carbon fiber diameter becomes thick and short, and there is a possibility that the aggregate that is a feature of the present invention cannot be obtained. Moreover, when too large, dispersion | distribution in resin may become difficult.

[1-2-5. Pore volume]
The pore volume of the bundle of the present invention is arbitrary as long as the aggregate of the present invention is obtained. However, the preferable range of the value measured by the mercury intrusion method is usually 10 mL / g or more and usually 22 mL / g or less. When the specific surface area is too small, the resin impregnation property may be inferior. When the specific surface area is too large, the bulk density becomes small, and handling on the transportation surface may be difficult. In addition, the pore distribution measurement by the mercury intrusion method can be performed using, for example, Autopore III9420 (manufactured by Micromeritics).

[1-2-6. Orientation of carbon fiber of the present invention]
As an index indicating the orientation of carbon fibers in the aggregate, an image obtained by cutting out a 30,000-fold image observed by SEM with 512 × 512 pixels is subjected to Fast Fourier Transform (FFT) processing, and the angle having the highest anisotropy A value obtained by dividing the FFT intensity by the integral value of the FFT intensity in all directions, that is, an intensity ratio can be used. Specifically, after Fourier transformation, an angular distribution of intensity of 32 pixels is obtained from the coordinate origin. At this time, in order to reduce noise, it is preferable to use the values of two pixels before and after and use the average value of a total of five pixels as the intensity ratio. Since the processed image is 512 × 512 pixels, if the length of one side of the processed image is L (μm), one pixel corresponds to L / 32 (μm). In addition, it is preferable to define the orientation by a method in which the major axis direction of the ellipse is 0 ° and the 360 ° omnidirectional is divided into 12 parts to separate the orientation angles.

  The stronger the orientation is, the closer the intensity ratio is to 1, and the more isotropic, the smaller the numerical value. In the case of showing complete isotropic property, the intensity ratio is 0.083 (1 / 12≈0.083). The intensity ratio of the SEM image obtained by photographing the aggregate of the present invention in a 30,000-fold image having a wavelength of 0.05 μm is usually 0.2 or more, preferably 0.26 or more, more preferably 0.3 or more, and usually 0. 0.5 or less, preferably 0.4 or less, more preferably 0.34 or less.

  Also, the value obtained by dividing the intensity ratio in the 30,000 times image having a wavelength of 0.05 μm by the intensity ratio in the 300 times image having a wavelength of 5 μm is usually 1.5 or more, especially 2 or more, particularly 2.5 or more. Is preferred. Further, the upper limit is usually 5 or less, preferably 4.5 or less, particularly 4 or less. If this value is too small, a certain orientation may not be obtained and a bundle may not be formed. If it is too large, the orientation may be too high to form a bundle aggregate.

[1-3. Aggregate of the present invention]
[1-3-1 Overview]
The aggregate of the present invention is an aggregate of fine hollow carbon fibers in which a plurality of linear fibers having a certain orientation are gathered to form a bundle, and the bundle is intertwined and aggregated. This aggregate does not have a fixed shape, but has a variety of shapes ranging from an entangled substantially spherical shape to a gathered shape while maintaining a gentle curve.

[1-3-2. Advantages of the assembly of the present invention]
Unlike the conventional carbon fiber, the aggregate of the present invention is not a tangled carbon fiber one by one, but a tangled bundle. For this reason, compared with the conventional aggregate | assembly, a bundle | flux is easy to unwind from an aggregate | assembly, and also carbon fiber is easy to disperse | distribute from a bundle | flux. Therefore, when the aggregate of the present invention is dispersed in any medium, the carbon fibers can be easily and highly dispersed in the medium.

[1-3-3. Application]
The aggregate of the present invention can be suitably used, for example, for producing a conductive resin, taking advantage of the above-described high dispersibility. Specifically, since the carbon fiber itself has conductivity, if the aggregate of the present invention is dispersed in the resin, the resin can be imparted with a smaller amount of carbon fiber than before.

  Further, the carbon fiber of the present invention can be applied to an electromagnetic wave shielding agent, an antistatic electronic member, a resin molding for electrostatic coating, a conductive transparent resin composition, and the like. Moreover, the carbon fiber of this invention can be applied to resin compositions, such as a sheet | seat, a tape, a transparent film, ink, and a conductive paint other than a molded object.

[2. Method for producing aggregate of the present invention]
The aggregate of the present invention can be produced by any catalyst, method, process, raw material and the like as long as the effects of the present invention are not significantly impaired. However, among these, the aggregate of the present invention is preferably produced by a vapor deposition method. Hereinafter, although the manufacturing method of the aggregate | assembly of this invention is given and an example is demonstrated, the content described below is a specific example to the last, and is not limited to the following content.

[2-1. Vapor growth carbon fiber production catalyst]
[2-1-1. Overview]
The catalyst suitably used for producing the aggregate of the present invention (hereinafter referred to as “the catalyst of the present invention” as appropriate) is a catalyst for producing the carbon fiber of the present invention, and has a flat surface on the surface. It is a powder made of a metal-containing material.

  However, the “plane” here is not a strict plane in mathematics, but a plane having a flat surface when viewed from a macroscopic viewpoint. The flatness of the plane is arbitrary as long as the aggregate of the present invention can be obtained, but preferably the plane area, plane error, and the ratio of the equal area radius to the approximate sphere radius are described in detail below. It represents a “plane” in the numerical range.

[2-1-2. Physical properties]
[2-1-2-1. composition]
The catalyst of the present invention is preferably made of a metal-containing material. In this case, when an example of the metal contained in the metal-containing material is given, the metal-containing material is composed of a combination of one or more kinds of group A composed of Co, Ni, and Fe and one or more kinds of group B composed of Al and Mg. And the like. Of these, a combination of Co and Al is preferable. This is because it is possible to form a catalyst structure suitable for producing bundles and / or aggregates in a wide range of blending ratios.

  Further, the metal-containing material may be a single metal or a metal compound. Examples of the metal compound include metal oxides, metal nitrides, metal sulfides, metal halides, and metal salts. Among these, the metal compound is preferably a metal oxide. In addition, the catalyst of this invention may contain only 1 type of the said metal containing material, and may contain 2 or more types by arbitrary ratios and combinations. Furthermore, the catalyst of the present invention may optionally contain other substances besides these metal-containing materials as long as the performance of the catalyst of the present invention is not impaired.

[2-1-2-2. Plane area, plane error, and ratio of equi-area radius to approximate sphere radius]
The catalyst of the present invention has very small particles, and it is difficult to evaluate the flatness. Accordingly, the present inventors examined the planarity of the catalyst surface to such an extent that the physical properties of the produced carbon fiber of the present invention can be controlled, and the desired carbon fiber is obtained by using the method described below. It was found that the flatness of the catalyst surface can be appropriately evaluated. Accordingly, the catalyst of the present invention preferably has the planarity evaluated by the method described below. Specifically, the planar area, the plane error, the equal area radius (r) and the approximate spherical radius (R) in the plane. ) (R / r; hereinafter referred to as “R / r” as appropriate) is preferably within the range described below. Since the measurement method is peculiar to the catalyst of the present invention, first, the measurement method will be described here.

[2-1-2-2-1. Method for measuring plane area and plane error]
First, the catalyst is observed from one direction with a laser microscope, and the planar area (one-side planar area) of the visible catalyst is measured. The magnification of the lens is preferably 150 times. At this time, measurement is performed on at least 20 catalysts. Based on the measured planar area, the planar areas of the catalyst in the range of 1 μm 2 or more and 1000 μm 2 or less are added together, and the ratio to the total of the measured planar areas of all the catalysts is calculated.

On the other hand, in a laser microscope, the height (catalyst height data measured by a laser microscope) is measured for a catalyst whose visible planar area (one-side planar area) is in the range of 5 μm 2 or more and 1000 μm 2 or less. And the plane error is calculated.
As a laser microscope, VK-9500 manufactured by Keyence Corporation can be used. The inside of the field of view observed with the microscope at a magnification of 150 × is scanned with a laser, divided and scanned into 1024 × 768 pixels (total number of pixels in the entire field of view), and stored as digital data. Under this condition, the pixel in the catalyst is 0.093 μm / pixel.

  The plane error existing on the catalyst surface is calculated by performing plane approximation by the least square method on the same particle height data obtained from an image observed with a laser microscope and solving the plane equation. The planar area is calculated by adding the pixel sections of the image data of the planar catalyst obtained by the laser microscope to calculate the apparent planar area. Furthermore, the catalyst angle (the inclination that occurs because the target catalyst sample cannot always be horizontal) The plane area is calculated by calculating so that the catalyst is placed horizontally again. The plane equation is to perform a three-dimensional image labeling process by performing plane approximation by the least square method on the actual height data for each total number of pixels (number of measurement points) of the catalyst obtained from the measurement data.

  The plane error in the plane is a standard deviation representing the degree of curvature or the degree of unevenness of the actual surface area with reference to the approximate plane. That is, the plane angle is obtained from the plane approximation formula, the plane area is integrated, and the sum of the squares of the difference between the actual height and the approximate plane height is divided by the number of measurement points (total number of pixels obtained by image processing). Is the variance, and the square root of the variance is the standard deviation. The variance and the standard deviation here are synonymous with terms generally used in statistics. The approximate plane is an apparent average height obtained by calculating the actual height of each pixel of the catalyst obtained by image processing and the total number of pixels of the catalyst by the least square method.

  If the catalyst and the surface to be observed are selected objectively and randomly, the selection method is arbitrary. Regarding the measurement of the plane error, when the value varies greatly depending on the surface to be observed, it is preferable to observe from the direction in which the plane error is as small as possible. The plane area and the plane error are preferably measured for 20 or more catalyst particles. The plane error is an average value at that time.

[2-1-2-2-2. Plane area]
The planar area of the catalyst of the present invention is arbitrary as long as the carbon fiber aggregate of the present invention is obtained. However, the total area of the plane present on the catalyst surface, the total planar area in the range of 1 [mu] m 2 or more 1000 .mu.m 2 or less, usually 50% or higher by the value measured by the method described above, is preferably 70% or more It is preferable. On the other hand it is also preferred that the total planar area in the range of 5 [mu] m 2 or more 200 [mu] m 2 or less is 25% or more of the total area of the plane present on the catalyst surface. If the planar area is too small, carbon fibers having the desired orientation cannot be vapor-phase grown in a bundle shape, and the bundle and / or aggregate of the present invention may not be obtained. Moreover, when too large, the reaction efficiency may fall by the contact efficiency fall with source gas. Furthermore, since the bundle diameter tends to be large, it becomes difficult to unravel the fibers in the bundle, and the dispersion of the aggregate of the present invention into the resin may be insufficient. Therefore, unevenness due to the carbon fiber non-dispersed mass is generated on the resin surface, which may cause poor appearance or decrease the resin strength.

[2-1-2-2-3. Plane error in the plane]
Further, the plane error in the plane is arbitrary as long as the aggregate of the present invention is obtained. However, the plane error is a value measured by the above-described method and is usually 0.2 or more, preferably 0.3 or more, particularly 0.4 or more, and is usually 0.9 or less, particularly 0.8 or less, especially 0. It is preferable that it is 7 or less. If the plane error is too small, the orientation of the carbon fiber bundles is too high, and it is difficult to obtain an appropriate aggregate between the bundles, which may cause difficulty in handling due to a decrease in bulk density, and is too large There is a possibility that carbon fibers having the desired orientation cannot be obtained.

[2-1-2-2-4. More preferred aspects of plane area and plane error]
In the catalyst of the present invention, it is particularly preferable that a plane having a plane error within the above range has the plane area. That is, in the catalyst of the present invention, among 20 or more catalysts, the plane error is particularly preferably 50% or more of the total plane area when the plane areas of the catalyst within the above range are added. preferable.

[2-1-2-2-5. Method for measuring the ratio of equal area radius to approximate spherical radius]
Moreover, when evaluating the flatness of a catalyst, it can also evaluate using the curvature radius of a spherical surface. That is, when the catalyst is regarded as a virtual circle having the same area, and the virtual circle is regarded as a part of the spherical surface, when it becomes a complete spherical surface, a sphere having the spherical surface (hereinafter referred to as “approximate sphere” as appropriate). The method of calculating the radius R can be used. Therefore, it can be said that the larger the radius R, the more planar the catalyst.

  As a specific method, it can be evaluated by the method described below. That is, first, an equal area radius r is calculated from the planar area of the catalyst measured with a laser microscope. Here, “equal area radius” represents the radius of a virtual circle having the same area as the planar area of the catalyst. By this operation, the actual area of the catalyst can be converted into the area when the catalyst is a part of a sphere (hereinafter referred to as “approximate sphere” as appropriate). On the other hand, the center of gravity of the catalyst plane is calculated, a normal line (that is, a normal to the approximate plane) is drawn from the center of gravity, and the length of the normal vector is R. The “center of gravity” represents the center of gravity in the shape of the catalyst viewed from the direction perpendicular to the approximate plane. At this time, a point at which the variation between R and the actual measurement point of each catalyst (that is, equivalent to “dispersion” in statistics) is minimized is obtained, and this is determined as a temporary center point (that is, a temporary approximate sphere). Represents the center of

  From this temporary center point, for example, an optimization algorithm using numerical analysis software or the like is performed to determine the final R (that is, the radius of the approximate sphere) and the center point (that is, the center of the approximate sphere). To do. At this time, it is preferable that the normal vector itself is also adjusted so that the virtual circle and the approximate spherical surface most closely match. Therefore, it can be said that the larger the radius R, the more planar the catalyst.

  As a more specific method, for example, the following method can be used.

  That is, first, a median filter is applied to an image of the same particle height observed with a laser microscope, noise is removed, and then particles are extracted by binarization, and a labeling process is performed. Here, binarization that is the center of the area of the catalyst is an operation of separating the measured catalyst and the background, and is an operation of discriminating a boundary at a certain height or more and extracting it as image data. Further, by measuring the planar area of the catalyst based on the image subjected to the labeling process, it is possible to calculate an equal area radius (r) when the catalyst is viewed from the measurement upper surface for each catalyst particle. At this time, as analysis software, for example, MATLAB® ver. 7.3 (2006b) (manufactured by Cybernet System) can be used. The calculation upper limit of each calculation value in the analysis software may not be determined unless the effects of the present invention are significantly impaired. However, from the viewpoint of reducing the calculation load of the analysis software, the calculation upper limit of the radius is set to 50R (R = 1 μm) is preferable.

  Next, [2-1-2-2-1. Plane area and plane error measurement method], the plane approximation is performed on the same particle height data obtained by the same method as the least square method, and the plane equation is solved for the same particle height data (plane error). Thus, the area of the approximate plane is calculated. On the other hand, a point obtained by extending the normal vector of the length (R) from the calculated center of gravity of the catalyst plane is set as the initial value of the temporary center point. Move the temporary center point on the normal vector (length: between 0.5R and 50R), calculate the distances from all the height data points, The center point.

  Move the X, Y, and Z axes within the range of ± 0.5R from the temporary center point, calculate the distance to the height data point in the same way, calculate the center where their standard deviation is minimum, The center of the final approximate sphere. At this time, the normal vector itself is adjusted as necessary. The length of the normal vector from the calculated center is the approximate sphere radius (R).

[2-1-2-2-6. Ratio of equal area radius to approximate sphere radius]
Further, the average value of the ratio (R / r) between the equal area radius (r) and the approximate spherical radius (R) calculated by regarding the catalyst as a part of the sphere is particularly as long as the aggregate of the present invention is obtained. Although there is no restriction | limiting, Preferably it is 5 or more, More preferably, it is 9 or more, More preferably, it is 14 or more. The upper limit is not particularly limited, but is usually 1000 or less in consideration of the general processing capability of the electronic computer when the analysis software is used. If R / r is too small, the planarity of the catalyst is low, so that it becomes closer to a sphere and there is a possibility that the aggregate that is a feature of the present invention cannot be obtained. Moreover, the produced carbon fiber may come to have a bent and entangled structure generally known in the art. On the other hand, if R / r is too large, the upper limit that can be calculated by the analysis software will be exceeded, so there is a possibility that an accurate radius cannot be obtained. In general, if the value of R / r is 50 or more, it can be regarded as a flat surface. The average value of R / r is preferably measured and calculated for 20 or more catalyst particles, as in the case of the plane error.

[2-1-2-2-7. More preferable aspect of plane area and ratio of equal area radius to approximate spherical radius]
In the catalyst of the present invention, it is particularly preferable that a plane having a plane area within the above range has the above R / r. That is, in the catalyst of the present invention, among the 20 or more catalysts, the plane area of the plane measured by a laser microscope in a plane of 50% or more with respect to the total area of the planes existing on the catalyst surface is 1 μm. The average value of the ratio (R / r) between the equivalent radius (r) of the catalyst in the range of 2 to 1000 μm 2 and the approximate spherical radius (R) calculated by regarding the catalyst as a part of a sphere is Particularly preferred is 5 or more.

[2-1-2-3. Average particle size]
The particle size of the catalyst of the present invention is arbitrary as long as the aggregate of the present invention is obtained. However, in the dry particle size distribution measurement by the laser diffraction method, the average particle diameter D 50 of the catalyst at a normal distribution of 50% is usually 0.1 μm or more, preferably 1.52 μm or more, particularly preferably 2.39 μm or more. The upper limit is usually 100 μm or less, preferably 90 μm or less, and particularly preferably 80 μm or less. If the average particle diameter D 50 is too short, a plane having a desired planar area and the plane errors and / or R / r is destroyed, there is a possibility that the catalyst is not obtained in the present invention, if it is too long, the catalyst There is a possibility that the contact surface with the source gas is reduced and the reaction efficiency is lowered.

Mean measuring device used to measure the particle diameter D 50 is, for example, can be used Seishin Enterprise Co. "LMS-300".

[2-1-2-4. shape]
The shape of the catalyst of the present invention is arbitrary as long as it has the flatness to obtain the aggregate of the present invention. As an example thereof, it is preferable to use a powder in the form of a block, a plate, or a flake because the planar area of the catalyst is wide.

[2-1-2-5. The bulk density]
The bulk density of the catalyst of the present invention is arbitrary as long as the aggregate of the present invention is obtained. However, usually 0.05 g / cm 3 or more as a preferable range of the bulk density of the catalyst, preferably 0.08 g / cm 3 or more, particularly preferably 0.1 g / cm 3 or more and usually 1 g / cm 3 or less, preferably Is preferably 0.9 g / cm 3 or less, more preferably 0.8 g / cm 3 or less. If the bulk density is too small, it may be entrained in the raw material gas during the carbon fiber production reaction, resulting in clogging of the device. If it is too large, the carbon fibers will be densely assembled to obtain the aggregate of the present invention. Can be difficult.

  Here, the bulk density can be measured by any method. For example, after slowly pouring a sample into a container of a certain volume, leveling with a spatula and measuring the weight twice, the bulk density can be calculated based on the measurement result. As a more specific measuring method, JIS K6219 can be used.

[2-1-2-6. Specific surface area of catalyst]
The specific surface area of the catalyst of the present invention is arbitrary as long as the aggregate of the present invention is obtained. However, as a preferable range of the specific surface area of the catalyst, a BET specific surface area value measured by a nitrogen adsorption method is usually 1 m 2 / g or more, preferably 5 m 2 / g or more, particularly preferably 10 m 2 / g or more. Usually, it is 300 m 2 / g or less, preferably 250 m 2 / g or less, particularly preferably 200 m 2 / g or less. If the specific surface area is too small, the contact efficiency with the raw material gas may be reduced. If it is too large, it may be difficult to give the catalyst a flat portion, and the aggregate of the present invention may not be obtained. is there.

[2-1-3. Method for producing catalyst of the present invention]
Hereafter, the manufacturing method of the catalyst of this invention is demonstrated concretely. However, the catalyst of this invention is not limited to what is manufactured with the following manufacturing methods.

[2-1-3-1. material]
As a raw material of the catalyst of the present invention, any material can be used as long as it contains a metal contained in the metal-containing material. Moreover, a raw material may use only 1 type and may use 2 or more types by arbitrary ratios and combinations.
Among these, it is preferable to use a metal compound as a raw material. Furthermore, among them, a metal compound (hereinafter referred to as “A group metal compound” as appropriate) including at least one metal selected from Group A consisting of at least Co, Ni and Fe (hereinafter referred to as “A group metal” as appropriate); And a metal compound containing one or more metals selected from the group B consisting of Al and Mg (hereinafter referred to as “group B metal” as appropriate) (hereinafter referred to as “group B metal compound” as appropriate). ) In combination.

  Among group A metals, Co is preferably used as the group A metal. This is because Co is a raw material for cobalt oxide as an active component of the catalyst. In addition, only 1 type of A group metal may be contained in the A group metal compound, and 2 or more types may be contained by arbitrary ratios and combinations.

  The group A metal compound may be any type of metal compound. For example, metal oxides, metal nitrides, metal sulfides, metal halides, metal salts, and the like can be given. Among these, the metal compound is preferably a metal salt, and particularly preferably a metal nitrate. The reason is that an appropriate foaming phenomenon occurs at the time of calcination for producing the catalyst, and it is easy to obtain a catalyst having an appropriate surface area by uniformly dispersing the metal. In addition, as a group A metal compound, only 1 type may be used and 2 or more types may be used together by arbitrary ratios and combinations.

  On the other hand, as the group B metal, it is preferable to use Al among the above metals. This is because Al serves as a raw material for aluminum oxide as a carrier for the cobalt oxide. In addition, in the B group metal compound, only 1 type of B group metal may be contained, and 2 or more types may be contained by arbitrary ratios and combinations.

  The group B metal compound may be any type of metal compound. For example, metal oxides, metal nitrides, metal sulfides, metal halides, metal salts, and the like can be given. Among these, the metal compound is preferably a metal salt, and particularly preferably a metal nitrate. The reason is that an appropriate foaming phenomenon occurs during the calcination for producing the catalyst, and the group A metal can be uniformly supported on the surface. In addition, as a B group metal compound, only 1 type may be used and 2 or more types may be used together by arbitrary ratios and combinations.

  When a group A metal compound and a group B metal compound are used in combination as raw materials, the ratio of the group A metal compound to the group B metal compound is arbitrary as long as the catalyst of the present invention is obtained. However, the proportion of both is such that the content of the group A metal is usually 10 mol% or more, preferably 15 mol% or more, with respect to the total of the group A metal and the group B metal in the catalyst obtained after calcination described later. More preferably, it is 20 mol% or more. When the content ratio of the group A metal is too low, the catalytic activity is low and the carbon fiber generation amount may be low. Moreover, as an upper limit of the content rate of the said A group metal, it is 50 mol% or less normally, Preferably it is 45 mol% or less, More preferably, it is 40 mol% or less. When the content ratio of the group A metal is too high, the particle diameter is excessively large and the variation in the carbon fiber wire diameter may increase, and the orientation of the carbon fiber and the uniformity in the growth direction may be reduced. As a result, an increase in the group A metal (cobalt or the like) that does not contribute to the reaction efficiency may occur and the reaction efficiency may decrease.

[2-1-3-2. Mixing raw materials]
After preparing the catalyst raw materials, these are mixed (hereinafter referred to as “mixing step” as appropriate). In the mixing step, the mixing can be performed in any manner as long as the catalyst of the present invention is obtained. Hereinafter, although an example of operation of a mixing process is explained concretely, it is not limited to the following methods.

  When mixing the raw materials, other components may be mixed with the raw materials as necessary. Examples of other components include organic compounds. In particular, when a group A metal compound and a group B metal compound are used in combination as raw materials, it is preferable to mix any organic compound as the other component. As the organic compound to be mixed, an organic compound that is compatible with the group A metal-containing material and forms a complex is preferable. Among them, an organic compound having an oxygen atom, such as having a carboxyl group, a hydroxyl group, an amino acid group or the like in the same molecule is preferable. Specific examples include carboxylic acids, carboxylic acid derivatives such as hydroxycarboxylic acids and carboxylic acid esters, amino acids, amides, amines, and hydrates and anhydrous salts thereof. Among these, an organic compound having a low decomposition temperature, for example, an organic compound that decomposes at 300 ° C. or lower is more preferable, and a compound having a complex formation with a metal (that is, capable of becoming a ligand) is particularly preferable. Specific examples include citric acid, malic acid, tartaric acid, lactic acid, glycine, glutamic acid, glutamine, asparagine, arginine, phenylalanine, alanine, leucine, isoleucine and the like. Among these, a carboxylic acid compound is preferable, citric acid is more preferable, and glutamic acid is particularly preferable. Moreover, the said organic compound may be used only 1 type, and may use 2 or more types by arbitrary ratios and combinations.

  The ratio of the organic compound to be mixed is arbitrary as long as the catalyst of the present invention is obtained. However, the content ratio of the organic compound is usually 5% by weight or more with respect to the total weight of the group A metal compound and the group B metal compound present in the same system at the time of mixing. Is 8% by weight or more, and more preferably 10% by weight or more. When the content ratio of the organic compound is too small, there is a possibility that the particle size of the group A metal cannot be controlled. Moreover, the upper limit of the content ratio of the organic compound is usually 60% by weight or less, preferably 50% by weight or less, more preferably 40% by weight or less. When the content ratio of the organic compound is too large, there is a possibility that the sintering of the catalyst is caused by an exothermic reaction during the calcination decomposition.

  In addition, there is no restriction | limiting in the order which mixes other components, such as a raw material and an organic compound, It can mix in arbitrary orders.

  Moreover, although there is no restriction | limiting in the method of mixing a raw material, For example, it can mix as follows. That is, using a mortar or the like, at an industrial level, a biaxial mixer, a homomixer, a homogenizer, a blender mill, an automatic mortar and the like are sufficiently mixed to the extent that the catalyst of the present invention is obtained. The mixing step is not limited to such dry mixing, and may be a method in which these are dissolved in a solvent such as water and mixed, and then evaporated to dryness by heating or the like. Moreover, a mixing process may be performed only with 1 type of the said mixing method, and may be performed combining 2 or more types.

[2-1-3-3. Firing]
It is preferable to fire the mixture thus obtained (hereinafter referred to as “raw material mixture” as appropriate) (hereinafter referred to as “fired step” as appropriate). By this operation, the metal contained in the raw material is oxidized and the metal-containing material is obtained. The calcination step can be arbitrarily performed as long as the catalyst of the present invention is obtained. Hereinafter, although an example of operation of a baking process is demonstrated concretely, it is not limited to the following methods.

  As the calcination apparatus, any apparatus can be used as long as the catalyst of the present invention is obtained. Specific examples of the apparatus include a muffle firing furnace using electricity as a heating source.

  Further, as long as a desired metal-containing material is obtained, firing can be performed in any atmosphere, and specific examples include air, nitrogen, argon, and the like. One kind of the atmospheric gas may be used, or two or more kinds may be used in any ratio and combination.

・ Temperature raising step Although there is no particular limitation on the temperature raising rate in the temperature raising step, it is usually 2 ° C./min or more, preferably 5 ° C./min or more, more preferably 8 ° C./min or more, and usually 100 ° C./min. In the following, the temperature in the furnace is raised at a rate of temperature rise of preferably 80 ° C./min or less, more preferably 50 ° C./min or less. If it is too slow, decomposition may not proceed well and uniform loading may not be obtained. If it is too fast, internal heat generation may occur rapidly, resulting in catalyst sintering.

-Heat retention step The firing temperature in the heat retention step varies depending on the types of raw materials and organic compounds used, the composition ratio and the mixing order, etc., but is usually 300 ° C or higher, preferably 350 ° C or higher, more preferably 380 ° C or higher. Moreover, it is 500 degrees C or less normally, Preferably it is 450 degrees C or less, More preferably, it is 400 degrees C or less. If the temperature of the heat retention step is too low, a large amount of impurities may remain in the catalyst due to undecomposition of the organic compound, and the loading of the group A metal on the oxide of the group B metal may be insufficient. The catalyst can cause sintering.

  When an organic compound is contained in the raw material mixture, the organic compound is decomposed / vaporized and discharged by combustion in the firing step. In this case, the remaining carbon that could not be discharged is usually 10% by weight or less, preferably 8% by weight or less, and more preferably 5% by weight or less of the fired product. If there is too much residual carbon, it may become a growth inhibitory substance during the production of the remaining carbon fiber as an impurity of the catalyst.

[2-1-3-4. Crushing]
After the firing step, the mixture obtained by firing is preferably pulverized to a desired size (hereinafter referred to as “pulverization step” as appropriate). The pulverization step can be arbitrarily performed as long as the catalyst of the present invention is obtained. Hereinafter, the pulverization step will be described in detail, but is not limited to the following method.

  Although pulverization can be performed in any atmosphere, it is preferably performed in an inert gas. Specific examples of the inert gas include nitrogen and argon. Only one kind of atmospheric gas may be used, or two or more kinds may be used in any ratio and combination.

  Moreover, the temperature at the time of grinding | pulverization is also arbitrary and can be performed at normal temperature.

  The pulverization method is not particularly limited as long as the catalyst of the present invention can be obtained, but a mixer, a pin mill, a hammer mill, a pulverizer, a jet mill or the like can be used. Moreover, the grinding | pulverization process may use only 1 type of the said grinding | pulverization apparatus, and may use it in combination of 2 or more type.

  The degree of pulverization is preferably such that the plane error is within the range of the plane error of the catalyst of the present invention described above in the plane of the catalyst.

  Further, when pulverizing, in order to maintain a desired pulverization particle size and flatness, the number of revolutions of the pulverizer, the pressure of the airflow, and the like are arbitrarily adjusted. For example, when pulverization is performed with an accompanying airflow pressure such as a jet mill, the pressure is preferably 0.01 MPa or more, more preferably 0.1 MPa or more. Moreover, the upper limit becomes like this. Preferably it is 1 MPa or less, More preferably, it is 0.5 MPa or less. Further, when pulverization is performed by rotation such as a mixer or a pin mill, the performance varies greatly depending on the model to be selected.

  In addition, the aggregate | assembly of this invention is obtained by using the catalyst which has a plane on the surface. In order to have a flat surface on the catalyst surface, when the raw material mixture is fired, it is desirable that the particles of the fired raw material mixture have a flat surface. The raw material mixture after firing generally takes a large lump form in which particles are aggregated. Therefore, in order to obtain such particles, [1-3-1. When the type of the metal-containing material described in “Raw material” is controlled, and when the raw material mixture contains a group A metal and a group B metal [1-3-1. A method such as controlling the content of the group A metal described in the “Raw Materials” can be considered. And the method of grind | pulverizing or crushing the raw material mixture after baking so that the shape of the particle | grains which have a plane may be maintained by the conditions which satisfy | fill said range, for example is mentioned. By this pulverization or pulverization, a powdered catalyst having a flat surface can be obtained.

[2-1-3-5. Activation of catalyst]
The catalyst of the present invention can be obtained by pulverizing as described above and activating the catalyst. For activation of the catalyst, any method can be used. For example, the catalyst may be placed in a reducing atmosphere. Specific examples include contact with a carbon fiber raw material gas, which will be described later, together with the reducing gas. Preferable examples of the reducing gas include hydrogen and ammonia. One reducing gas may be used, or two or more reducing gases may be used in any ratio and combination.

[2-2. Method for producing aggregate of the present invention]
By using the catalyst of the present invention described above and carrying out the production method of the present invention, it is possible to obtain a novel carbon fiber aggregate that has not existed before. Below, this manufacturing method is demonstrated.

[2-2-1. Overview]
The aggregate of the present invention is produced using a raw material gas containing carbon in the presence of the catalyst of the present invention.

[2-2-2. Raw material gas]
Any material gas can be used as long as it contains carbon. Specific examples include hydrocarbons such as methane, ethane, propane, ethylene, and acetylene, carbon monoxide, and alcohol. In particular, carbon monoxide is preferable. The source gas may be used alone or in combination of two or more in any ratio and combination.

  In particular, when carbon monoxide is contained in the source gas, the carbon monoxide concentration is preferably 50% by volume or more, more preferably 60% by volume or more, and particularly preferably 70% by volume or more. Further, it is preferably 99% by volume or less, more preferably 98% by volume or less, and particularly preferably 95% by volume or less. If the concentration is too low, the reaction rate may be significantly reduced. Moreover, when a density | concentration is too high, it may become a cause by which the gas concentration ratio for promoting reaction falls.

  As long as the aggregate of the present invention is obtained, the raw material gas can contain other components in any ratio and combination. Examples of other components include water. In particular, it is preferable to use a combination of carbon monoxide and water. The reason is unknown, but it is presumed that water contributes to prevention of catalyst deactivation due to coking action during the growth of carbon fibers from the catalyst.

  When water is used as the other component, the concentration of water in the raw material gas is preferably 0.1% by volume or more, more preferably 0.15% by volume or more, and particularly preferably 0.2% by volume or more. Is preferably 1% by volume or less, more preferably 0.8% by volume or less, and particularly preferably 0.6% by volume or less. A water concentration within this range is preferable because the amount of carbon fiber produced per catalyst can be increased.

  The source gas particularly preferably contains a combination of carbon monoxide having a concentration within the above range and water having a concentration within the above range. That is, the raw material gas particularly preferably contains 50% by volume to 95% by volume of carbon monoxide and 0.1% by volume to 1% by volume of water.

  The source gas preferably contains hydrogen gas. The content of hydrogen gas is usually 1% by volume or more, preferably 3% by volume or more, more preferably 5% by volume or more. Moreover, the upper limit is 50 volume% or less normally, More preferably, it is 40 volume% or less, Most preferably, it is 30 volume% or less. By using a source gas containing hydrogen gas, an advantage of promoting the reaction can be obtained. Although the details of the reason are unclear, it is presumed that hydrogen having a reducing action may prevent deactivation due to oxidation of the catalyst.

[2-2-3. Source gas supply speed]
As long as the aggregate of the present invention is obtained, the assembly of the present invention is a flow type in which the raw material gas is continuously supplied to the reaction vessel, and the batch in which the raw material gas and the catalyst are sealed and reacted in the same system in advance. This can be done by any method such as a formula.

In the case of producing by the flow method, the feed rate of the raw material gas is 0.03 Nm 3 / h or more, more preferably 0.1 Nm 3 / h or more, particularly preferably 0.3 Nm 3 / h or more per 1 g of the catalyst. . And the upper limit thereof is preferably 3 Nm 3 / h or less, more preferably 1.5 Nm 3 / h, particularly preferably at most 1 Nm 3 / h. If the supply rate is too slow, the reaction rate may be significantly reduced, resulting in a reaction stall.If the supply rate is too fast, excessive supply of raw material gas may increase costs and entrain the catalyst, causing clogging of the equipment. is there.

[2-2-4. Reaction temperature]
The reaction temperature is arbitrary as long as the aggregate of the present invention is obtained, but it is preferably 480 ° C. or higher, more preferably 520 ° C. or higher, particularly preferably 560 ° C. or higher. Further, it is preferably 660 ° C. or lower, more preferably 650 ° C. or lower, and particularly preferably 640 ° C. or lower. If the reaction temperature is too low, the reaction efficiency may be lowered or the reaction may be stalled. If the reaction temperature is too high, the catalyst may be sintered, which may cause the reaction stall.

[2-2-5. Reaction pressure]
The reaction pressure is arbitrary as long as the aggregate of the present invention is obtained, but is preferably 5 kPa or more, more preferably 10 kPa or more, and particularly preferably 20 kPa or more. Further, the upper limit is not particularly limited from the viewpoint of the reaction mechanism, but is preferably 40 kPa or less, particularly preferably 30 kPa or less in consideration of airtightness in the reaction apparatus.

[2-2-6. Reaction time]
The reaction time is arbitrary as long as the aggregate of the present invention is obtained, but is usually 3 hours or longer, preferably 4 hours or longer, particularly preferably 5 hours or longer. Moreover, it is normally 12 hours or less. If the reaction time is too short, the amount of carbon fiber deposited on the catalyst is small, and the efficiency may deteriorate from the viewpoint of production cost. Further, since the carbon fibers are in the process of growing, there is a possibility that the length thereof is short and the bundles are not gathered in a bundle shape, and it is difficult to obtain the bundle-like aggregate that is a feature of the present invention.

[2-2-7. Other processes]
After completion of the reaction, other steps may be performed as long as the excellent advantages of the obtained aggregate of the present invention are not significantly impaired. For example, the reaction product is preferably stored in an inert gas. This is because the temperature is high immediately after the completion of the reaction, and sudden exposure to air may cause the carbon fiber to generate heat or ignite. Therefore, it is preferable to cool to room temperature under an inert gas. Specific examples of the inert gas include nitrogen and argon. One kind of the inert gas may be used, or two or more kinds may be used in any ratio and combination.

[2-2-8. manufacturing device]
In addition, as a manufacturing apparatus, as long as the aggregate | assembly of this invention is obtained, arbitrary things can be used. For example, a heat-resistant container covered with a stainless steel cover can be used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless it deviates from the summary.

[1. Production of catalyst]
<Example 1>
Cobalt nitrate hexahydrate 175 g (0.60 mol), aluminum nitrate nonahydrate 525 g (1.4 mol), and L-glutamic acid 89 g were weighed, mixed and ground in a mortar until uniform. This mixture was placed in a heat-resistant crucible and baked in an air atmosphere at 450 ° C. for 1.5 hours using an electric furnace.

  The compound obtained by baking was ground in a mortar until it became a powder. Thereafter, the compound was pulverized using a jet mill (FS-4 manufactured by Seishin Enterprise) to obtain the catalyst of the present invention (hereinafter referred to as “catalyst A” as appropriate). The atmosphere was performed in nitrogen gas controlled to 0.1 to 0.3 MPa.

<Comparative Example 1>
Catalyst A was dispersed in water, pulverized at a rotational speed of 2000 rpm for 1 hour using 0.5 mm diameter zirconia beads, and dried to obtain a powdery catalyst (hereinafter referred to as “catalyst B” as appropriate). .

<Comparative example 2>
175 g (0.60 mol) of cobalt nitrate hexahydrate, 356 g (1.4 mol) of magnesium nitrate hexahydrate, and 137 g of citric acid monohydrate were weighed, mixed and ground in a mortar until uniform. . This mixture was placed in a ceramic container and baked in an air atmosphere at 450 ° C. for 1.5 hours using an electric furnace. (Catalyst composition: cobalt content = 30 mol%)

  Thereafter, the same operation as in Example 1 was performed to obtain a powdery catalyst (hereinafter referred to as “catalyst C” as appropriate).

<Particle size distribution measurement>
About Example 1, Comparative Example 1 and Comparative Example 2, [2-1-2-3. The particle size distribution was measured according to the method described in [Average particle diameter]. The results are shown in Table 1. The average particle diameter D 50 of the catalyst A 11.11Myuemu, average particle diameter D 50 of the catalyst B is 2.39Myuemu, average particle diameter D 50 of the catalyst C was 1.52 .mu.m (Table 1).

<SEM photography>
SEM photographs of Catalyst A, Catalyst B, and Catalyst C are shown in FIGS. 2 (a) to (c), FIGS. 3 (a) to (c), and FIGS. 4 (a) to (c). 2 (a) and 3 (a) are magnified 20000 times, FIG. 2 (b) and FIG. 3 (b) are magnified 10,000 times, and FIG. 2 (c) and FIG. 3 (c) are magnified 5000 times. It is the SEM photograph which was done. 4A is an SEM photograph enlarged 30000 times, FIG. 4B is 10000 times, and FIG. 4C is 3000 times enlarged.
2 (a) to 2 (c), it was found that the catalyst A had a flat surface. On the other hand, the catalyst B was further ground by bead milling the catalyst A, and it was found from FIGS. 3A to 3C that the catalyst B was refined into a spherical shape having fine irregularities on the surface. Moreover, it turned out that the catalyst C has the spherical shape with fine unevenness | corrugation similarly to the catalyst B (FIG. 4 (a)-(c)).

<Measurement of plane area and plane error>
The plane area and plane error were measured according to the following method.
Catalyst A, catalyst B, and catalyst C dispersed in ethanol were each dispersed in a slide glass with a static elimination blower, and the static elimination blower was again applied twice. Those height images were taken using a laser microscope (VK-9500 manufactured by Keyence Corporation). A 150 × objective lens was used for shooting. The image size was 95.1 μm × 71.2 μm, the calibration value was 0.093 μm / pixel, the measurement height was 0.287 μm, and the resolution was 0.051 μm / luminance. From the height image photographed by the above method, [2-1-2-2. Based on the method described in “Plane area, plane error, and ratio between equal area radius and approximate sphere radius”, catalyst particles were extracted and labeled. Thereafter, the same particle height data was obtained by performing image processing on the image subjected to the labeling processing. The results are shown in Tables 2 and 3. In Table 2, “CV” represents a coefficient of variation and is obtained by dividing the standard deviation by the average value.

Obtained in the area measurements made on the basis of the same particle height data, the average 28.9Myuemu 2 in the range of 5.3~122.7Myuemu 2, the area after converting the plane angle 41 ° (plane area) It was in the range of 5.5~194Myuemu 2 mean 41 .mu.m 2 (Table 2, Table 3). That is, the ratio of the planar area in the range of 1 to 1000 μm 2 was 100%.

  Further, 50% or more of the catalyst with respect to the total planar area was in a standard deviation of 0.205 to 0.898, and an average standard deviation (planar error) was 0.555 (Tables 2 and 3).

<Calculation of ratio of equal area radius and approximate sphere radius>
For each of the catalysts A, B, and C, the equivalent area radius and approximate spherical radius are set as [2-1-2-2-5. The ratio was calculated according to the method described in [Method for measuring ratio of equal area radius to approximate spherical radius]. In order to reduce the calculation load of the analysis software, the upper limit of the radius calculation was set to 50R (R = 1 μm). Therefore, the maximum radius of the approximate sphere is 50 μm.

  R / r was calculated based on the calculated value. The results are shown in Tables 4-7.

  Next, carbon fibers were produced using a raw material gas containing carbon in the presence of Catalyst A, Catalyst B, and Catalyst C.

<Raw gas>
Petroleum heavy oil (ethylene heavy end) was pyrolyzed, and the hydrogen concentration of the generated gas was adjusted by membrane separation (separation membrane module type 410 made by Ube Industries), and moisture was adjusted to obtain a raw material gas . The composition of the source gas is 86% by volume of carbon monoxide, 10% by volume of hydrogen, 2% by volume of carbon dioxide, 1% by volume of methane, 0.3% by volume of water, and a trace amount of heavy hydrocarbon.

<Manufacture of carbon fiber>
120 g of each of Catalyst A and Catalyst B was uniformly dispersed in a heat resistant container and sealed with a stainless steel cover. After sealing, the air in the container was replaced with nitrogen. The entire apparatus was heated by an electric furnace at the outer periphery, and when the temperature reached about 500 ° C., hydrogen was introduced to activate the catalyst. This activation was carried out for about 1 to 1.5 hours. After the activation of the catalyst, a raw material gas was introduced to start the reaction. The reaction temperature was lowered stepwise from 620 ° C. to 570 ° C. at a temperature drop rate of 15 ° C./min, and the reaction was carried out for 5.5 hours. The pressure during the reaction was 25-30 KPa. After completion of the reaction, the inside of the container was replaced with nitrogen, heating by the electric furnace was stopped, and the mixture was naturally cooled to room temperature. After cooling, the container was opened to obtain carbon fibers.

  108 g of catalyst C was reacted in the same manner as in Example 1 to produce carbon fibers. However, the reaction temperature was lowered stepwise from 580 ° C. to 520 ° C. at a temperature drop rate of 20 ° C./min, and the reaction was carried out for 4.5 hours.

<TEM photography>
A TEM photograph of the obtained carbon fiber was taken with a transmission electron microscope (JEM-1230 manufactured by JEOL Ltd.). The number of carbon fiber layers was measured using a transmission electron microscope (HR-TEM / H9000UHR manufactured by Hitachi. LTD) high resolution type.

  For each of Example 1, Comparative Example 1 and Comparative Example 2, the outer diameter, the inner diameter and the number of layers of each of the 100 carbon fibers in the photographed TEM photographs were measured, and the average values thereof were Example 1 and Comparative Example 1. And the outer diameter, inner diameter, and number of layers of the carbon fiber of Comparative Example 2 (Table 1).

  The carbon fiber obtained in each of Example 1, Comparative Example 1 and Comparative Example 2 was subjected to SEM photography using a scanning electron microscope (JEOL Ltd., Model: JEOL JSM-7401F). The results are shown in FIG. 5, FIG. 6 and FIG.

  5 (a), (b), (c), (d) and (e) are SEM photographs enlarged to 300 times, 1000 times, 3000 times, 10000 times and 30000 times, respectively.

  FIGS. 6A, 6B, 6C, and 6D are SEM photographs enlarged to 300 times, 1000 times, 10000 times, and 30000 times, respectively.

  7A, 7B, 7C, and 7D are SEM photographs enlarged at 2000 times, 5000 times, 10000 times, and 30000 times, respectively.

  It can be seen that the carbon fiber using the catalyst A grows in a bundle shape from the plane of the catalyst as a base point, and has an aggregated form in which the bundle is intertwined. It was found that the orientation of the carbon fiber was strongly observed in the high magnification observation (FIGS. 5C to 5E) and weak in the low magnification observation (FIGS. 5A and 5B).

  The carbon fiber using the catalyst B and the catalyst C grows from the spherical surface of the catalyst in any SEM photograph at any magnification, the carbon fiber growth direction is not determined, and the carbon fibers are intertwined in a complicated manner. It did not have such orientation.

  Further, from the SEM photograph, the outer diameter of Example 1 was measured to calculate the length / diameter ratio, and the bundle was filled with fibers having an average carbon fiber diameter of 12.2 nm with almost no gap. The number was calculated (Table 1). In addition, as this average carbon fiber diameter, the average value of the outer diameter of 100 carbon fibers measured by TEM observation was used.

<Measurement of orientation of each carbon fiber>
About the carbon fiber obtained in each of Example 1, Comparative Example 1 and Comparative Example 2, [1-2-6. The orientation was measured according to the method described in [Orientation of carbon fiber of the present invention]. That is, for each photo in FIG. 5, an area of 512 × 512 pixels in the upper left, upper right, lower left, lower right, and center of the photo was extracted to reduce the influence of variation. The size of each image was 160 μm (300 times), 47.8 μm (1000 times), 16 μm (3000 times), 4.78 μm (10000 times), and 1.6 μm (30000 times). In all magnifications, the number of pixels was 32 pixels. The calibration values were 312.5 nm / pixel, 93.5 nm / pixel, 31.25 nm / pixel, 9.35 nm / pixel, and 3.125 nm / pixel, respectively. The image analysis processing software includes ImageProPlus Ver. 600 (manufactured by Nippon Roper) was used.

  The calculated intensity ratio was an intensity ratio of 0.1 at a wavelength of 10 μm and an intensity ratio of 0.12 at a wavelength of 5 μm in the 300-fold image, indicating no orientation. However, in the 30000 times image, the intensity ratio = 0.17 to 0.28 at the wavelength of 0.1 μm, the average intensity ratio = 0.21, the intensity ratio = 0.26 to 0.34 at the wavelength of 0.05 μm, and the average intensity. The ratio was 0.3, indicating a very strong orientation (Table 8).

  Similarly, when the orientation of the carbon fibers of Comparative Example 1 and Comparative Example 2 was calculated, the average strength ratio was very low, around 0.11, regardless of the magnification, and the mere entanglement was not achieved. Aggregates (Table 8).

<Resin kneading evaluation>
Carbon fiber and resin were kneaded at various ratios shown in Table 8 for 2 minutes under the conditions of 260 ° C. and 150 rpm using a Toyo Seiki plast mill to obtain a carbon fiber-containing resin. In addition, the carbon fiber obtained by using the catalyst A, the catalyst B, and the catalyst C was used in a state of being obtained, not a fiber that was not separated by mechanical pulverization or the like. The resin used was 6-nylon (Mitsubishi Engineering Plastics 1010C). A carbon fiber-containing resin kneaded with a plast mill was pressed to prepare a sheet for evaluating conductivity. The molding size was a flat plate of 100 × 100 × 2 mm (thickness). The press machine was a mini test press (ram diameter 65 mm, board surface 200 × 200) manufactured by Toyo Seiki Seisakusho, the compression force was 20 MPa in terms of ram pressure, the pressure applied to the board surface was about 1.6 MPa, and the temperature was 260 ° C.

The ends of the molded sheet were cut, silver paste was applied to both ends thereof, and the terminal of the measuring device was applied to measure the conductivity (hereinafter referred to as “volume resistance value” as appropriate). Loresta EP (manufactured by Mitsubishi Chemical) and Hiresta (manufactured by Toa Denpa) were used as measuring instruments. Loresta EP was used when the volume resistance value was 10 6 Ω · cm or less, and Hiresta was used when the volume resistance value was higher. The probe used is ESP type. Hiresta adopted a value of 500 V, charge for 1 minute, and 1 minute after the start of measurement using the ring method.

The results are shown in Tables 9 and 10, and those having a volume resistance value of 10 7 Ω · cm or more were designated as resins having excellent conductivity.

  The resin containing the aggregate made of the carbon fibers produced using the catalyst A has high conductivity even if the aggregate to be contained is small. On the other hand, the resin containing the aggregate made of the carbon fiber manufactured using the catalyst B has poor conductivity, and also contains the aggregate made of the carbon fiber manufactured using the catalyst C. The resin also had poor conductivity.

  The reason why the resin containing the aggregate of the present invention is excellent in conductivity is not clear, but according to the study of the present inventor, the carbon fibers constituting the bundle have orientation, so the conductive network is efficiently used in the resin. It is presumed that it can be formed automatically.

  The physical properties of the resin containing the aggregate produced in Example 1, the aggregate produced in Comparative Example 2, or Ketjen Black (KEC600; manufactured by Ketjen Black International) were measured. Each resin was manufactured as follows.

TEX-30α manufactured by Nippon Steel Works was used as the twin screw extruder, and 6-nylon (Mitsubishi Engineering Plastics 1010C or 1005J) was used as the resin. The temperature of the extruder was set to 250 ° C., kneading was performed at a screw rotation speed of 200 to 400 rpm and a discharge amount of 15 to 30 kg / h. Aggregates, aggregates or ketjen black and 6-nylon (1005J) were kneaded to prepare a high concentration master batch. Then, the masterbatch and 6 nylon (1010C) were diluted and adjusted to each concentration. The content of each carbon material in each resin is shown in Table 9. The injection molding machine used to manufacture the test pieces uses the NN100S type manufactured by Niigata Steel, the molding temperature is 270 ° C, the mold temperature is 80 ° C, the screw speed is 180rpm, the injection / cooling time is 35 seconds, and the injection speed. 2 seconds, injection pressure 24~29Kg / cm 2, and molded under the conditions of back pressure 3 kg / cm 2. The mold used the JIS family. The resin was dried at 80 ° C. for 7 hours before measurement. For comparison, 6-nylon not containing a carbon material was also evaluated.

  The volume resistance value, Charpy impact test and high-speed impact test (surface impact test) of each resin were performed, and the results are shown in Tables 11 and 12. As in the case of Example 1, the volume resistance value was determined as follows in the Charpy impact test and the high-speed impact test (hereinafter referred to as “surface impact test” as appropriate).

<Charpy impact test>
Based on JIS K7111, an average value was obtained at a test speed of 2 mm / min, a test temperature of 23 ° C., a relative humidity of 50%, and a test number n = 5.

<High-speed impact test>
Using a resin having a test piece shape of 120 × 80 × 2 mm, an average value was obtained at a hitting core diameter of 1/2 inch, a holder diameter of 2 inches, a test speed of 5 m / s, a test temperature of 23 ° C., and a test number of n = 5. . Note that MAX LOAD represents the breaking energy at the time of shooting, and BRAKE represents the energy up to penetration. The higher these numbers, the better the impact strength.

  From Table 11 and Table 12, the resin containing the aggregate of the present invention has high conductivity with a small content compared to a resin containing ketjen black and dumpling aggregates, which are conventional representative carbon materials. It turns out that sex can be obtained. Moreover, it turned out that intensity | strength does not deteriorate by making the aggregate | assembly of this invention contain in resin.

  When a carbon material is contained in the resin, the carbon material is difficult to uniformly disperse, and large aggregates that are considered to cause strength deterioration become undispersed, so that the strength generally deteriorates. However, when the aggregate according to the present invention is contained, it is presumed that the strength of the resin can be prevented from being deteriorated because the dispersion of the aggregate is easy.

The present invention provides a technique for mass-producing the aggregate of the present invention having excellent characteristics at a lower cost. Furthermore, the aggregate of the present invention is excellent in dispersibility in a resin and hardly deteriorates the mechanical properties of the resin, and can form an excellent conductive resin. This conductive resin can be applied to an antistatic electronic member, a resin molding for electrostatic coating, a conductive transparent resin composition, and the like. In particular, since it has an excellent balance between conductivity and strength, it can be used in the automotive field for automotive outer plate materials, automotive interior materials, automotive bumpers, and the like. In addition, since the aggregate of the present invention is excellent in dispersibility and conductivity, it can be applied to sheets, tapes, transparent films, inks, conductive paints, and the like.

Claims (11)

  1. Firing a metal compound containing one or more metals selected from Group A consisting of Co, Ni and Fe, and a metal compound containing one or more metals selected from Group B consisting of Al and Mg; A powder comprising a metal-containing material in which the content of the group A metal is 10 mol% or more and 50 mol% or less with respect to the total of the group A metal and the group B metal is used as a catalyst and contains carbon. An aggregate of fine hollow carbon fibers obtained using a raw material gas,
    In the aggregate, bundles of fine hollow carbon fibers oriented and assembled are intertwined and aggregated.
    An aggregate of fine hollow carbon fibers characterized by the above.
  2. In the photograph observed with a scanning electron microscope, the number of fine hollow carbon fibers contained in 50% or more of the 100 bundles that are not the same bundle is 10 or more and 10 6. An aggregate of fine hollow carbon fibers, characterized in that:
  3. An image obtained by cutting out a 30,000 times image observed with a scanning electron microscope with 512 × 512 pixels is subjected to a fast Fourier transform (FFT) process to divide the 360 ° omnidirectional portion into 12 portions to separate each orientation angle of the processed image. The orientation is defined by a technique, and the intensity ratio at an image wavelength of 0.05 μm is 0.2 or more of the value obtained by dividing the FFT intensity at the highest anisotropy angle by the integral value of the FFT intensity in all directions. The aggregate of fine hollow carbon fibers according to claim 1 or 2, wherein the aggregate is 5 or less.
  4. 4. The fine hollow according to claim 3, wherein a value obtained by dividing an intensity ratio in a 30,000 times image having a wavelength of 0.05 μm by an intensity ratio in a 300 times image having a wavelength of 5 μm is 1.5 or more. Aggregates of carbon fibers.
  5. The fine hollow carbon fiber according to any one of claims 1 to 4, wherein an average value of the outer diameter of the carbon fiber is 3 nm or more and 35 nm or less as observed by a transmission electron microscope. Aggregation.
  6. The aggregate of fine hollow carbon fibers according to any one of claims 1 to 5, wherein the fine hollow carbon fibers have a multilayer structure.
  7. The length of the carbon fiber measured by a scanning electron microscope is 10 times or more and 10 6 times or less with respect to the outer diameter of the carbon fiber. An aggregate of fine hollow carbon fibers according to one item.
  8. A method for producing an aggregate of fine hollow carbon fibers using a source gas containing carbon in the presence of a catalyst,
    As the catalyst, a metal compound containing one or more metals selected from the group A consisting of Co, Ni and Fe and a metal compound containing one or more metals selected from the group B consisting of Al and Mg are calcined. And using a powder comprising a metal-containing material in which the content of the group A metal is 10 mol% or more and 50 mol% or less with respect to the total of the group A metal and the group B metal. By
    A method for producing an aggregate of fine hollow carbon fibers, comprising obtaining an aggregate of fine hollow carbon fibers in which bundles of fine hollow carbon fibers oriented and assembled are intertwined and aggregated.
  9. The method for producing an aggregate of fine hollow carbon fibers according to claim 8, wherein the catalyst has a flat surface.
  10. 10. The fine catalyst according to claim 8, wherein the catalyst has an average particle diameter (D 50 ) at a normal distribution of 50% in a dry particle size distribution measurement by a laser diffraction method of 0.1 μm or more and 100 μm or less. A method for producing an assembly of hollow carbon fibers.
  11.   It manufactures by a vapor phase growth method, The manufacturing method of the aggregate | assembly of the fine hollow carbon fiber as described in any one of Claims 8-10 characterized by the above-mentioned.
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JP2002105765A (en) * 2000-09-28 2002-04-10 Toshiba Corp Carbon nanofiber compound and method for producing carbon nanofiber
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JP2006152490A (en) * 2004-11-30 2006-06-15 Jiemuko:Kk Carbon nanofiber excellent in dispersibility in resin and method for producing the same
JP2006181477A (en) * 2004-12-27 2006-07-13 Mitsubishi Chemicals Corp Catalyst for manufacturing carbon fiber by vapor growth process, and method for manufacturing carbon fiber
JP2008173608A (en) * 2007-01-22 2008-07-31 Mitsubishi Chemicals Corp Catalyst for producing vapor-phase growth carbon fiber and vapor-phase growth carbon fiber
JP2009090251A (en) * 2007-10-11 2009-04-30 Mitsubishi Chemicals Corp Catalyst and method for producing minute hollow carbon fiber using catalyst

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000017102A1 (en) * 1998-09-18 2000-03-30 William Marsh Rice University Catalytic growth of single-wall carbon nanotubes from metal particles
JP2002105765A (en) * 2000-09-28 2002-04-10 Toshiba Corp Carbon nanofiber compound and method for producing carbon nanofiber
JP2006506304A (en) * 2002-11-14 2006-02-23 ケンブリッジ・ユニヴァーシティ・テクニカル・サーヴィシズ・リミテッド Method for producing carbon nanotubes and / or nanofibers
JP2006152490A (en) * 2004-11-30 2006-06-15 Jiemuko:Kk Carbon nanofiber excellent in dispersibility in resin and method for producing the same
JP2006181477A (en) * 2004-12-27 2006-07-13 Mitsubishi Chemicals Corp Catalyst for manufacturing carbon fiber by vapor growth process, and method for manufacturing carbon fiber
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JP2009090251A (en) * 2007-10-11 2009-04-30 Mitsubishi Chemicals Corp Catalyst and method for producing minute hollow carbon fiber using catalyst

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