WO2009157529A1 - Carbon nanotube assembly and method for producing same - Google Patents

Carbon nanotube assembly and method for producing same Download PDF

Info

Publication number
WO2009157529A1
WO2009157529A1 PCT/JP2009/061675 JP2009061675W WO2009157529A1 WO 2009157529 A1 WO2009157529 A1 WO 2009157529A1 JP 2009061675 W JP2009061675 W JP 2009061675W WO 2009157529 A1 WO2009157529 A1 WO 2009157529A1
Authority
WO
WIPO (PCT)
Prior art keywords
carbon nanotube
carbon nanotubes
aggregate
catalyst
nanotube aggregate
Prior art date
Application number
PCT/JP2009/061675
Other languages
French (fr)
Japanese (ja)
Inventor
謙一 佐藤
秀和 西野
和義 樋口
Original Assignee
東レ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 東レ株式会社 filed Critical 東レ株式会社
Publication of WO2009157529A1 publication Critical patent/WO2009157529A1/en

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/78—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with alkali- or alkaline earth metals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/20—Conductive material dispersed in non-conductive organic material
    • H01B1/24—Conductive material dispersed in non-conductive organic material the conductive material comprising carbon-silicon compounds, carbon or silicon

Definitions

  • the present invention relates to an aggregate of carbon nanotubes and a method for producing the same. Further, the present invention relates to a molded body, a composition, and a conductive composite including a carbon nanotube aggregate.
  • Carbon nanotubes have a substantially cylindrical shape formed by winding one surface of graphite.
  • Single-walled carbon nanotubes are referred to as single-walled carbon nanotubes
  • multi-walled carbon nanotubes are referred to as multi-walled carbon nanotubes.
  • carbon nanotubes usually have a high graphite structure when the number of layers is smaller, and single-walled carbon nanotubes have high characteristics such as electrical conductivity and thermal conductivity. Since multi-walled carbon nanotubes have a low degree of graphitization, it is also known that electrical conductivity and thermal conductivity are generally lower than single-walled carbon nanotubes.
  • multi-walled carbon nanotubes are known to have higher durability than single-walled carbon nanotubes because of the large number of graphite layers.
  • double-walled carbon nanotubes are attracting attention as promising materials in various applications because they have the characteristics of both single-walled carbon nanotubes and multi-walled carbon nanotubes.
  • carbon nanotube aggregates having a high proportion of double-walled carbon nanotubes can be synthesized by chemical vapor deposition, plasma method, pulse arc method or the like.
  • Patent Document 1 and Non-Patent Document 1 produce double-walled carbon nanotubes with relatively high quality and high purity by catalytic chemical vapor deposition.
  • the carbon nanotubes of Patent Document 1 have a strong and very large bundle structure, the nano effect of each carbon nanotube cannot be exhibited, and various application developments are difficult. It is guessed. In particular, since it is very difficult to disperse in a resin or a solvent, development in various applications is limited. Further, since the carbon nanotubes of Non-Patent Document 1 are synthesized using a horizontal fixed bed reactor, the contact of the raw material gas with the catalyst is not uniform, and high-quality carbon nanotubes are not obtained.
  • Patent Document 2 discloses a method for synthesizing double-walled carbon nanotubes by bringing methane as a raw material gas into contact with a catalyst at a linear velocity of 9.5 ⁇ 10 ⁇ 3 cm / sec or less. Although a relatively high quality double-walled carbon nanotube is obtained, the Raman G / D ratio is about 20. At present, amorphous carbon is generated, and a very high quality double-walled carbon nanotube aggregate has not been obtained.
  • the present invention has been made in view of the above circumstances, and an object of the present invention is to obtain a double-walled carbon nanotube aggregate having very high conductivity, high quality, and good dispersibility, and a method for producing the same.
  • the present invention is an aggregate of carbon nanotubes that satisfies all the following conditions (1) to (4).
  • the volume resistivity of the carbon nanotube aggregate is 1 ⁇ 10 ⁇ 4 ⁇ ⁇ cm or more and 1 ⁇ 10 ⁇ 2 ⁇ ⁇ cm or less;
  • 50% or more of the carbon nanotubes in the aggregate of carbon nanotubes are double-walled carbon nanotubes;
  • the Raman G / D ratio of the carbon nanotube aggregate at a measurement wavelength of 532 nm is 30 or more and 200 or less;
  • the combustion peak temperature of the carbon nanotube aggregate is 550 ° C. or higher and 700 ° C. or lower.
  • the present invention is also a method for producing a carbon nanotube aggregate by contacting a raw material gas and a catalyst in a reactor, wherein the raw material gas containing methane at a concentration of 10% by volume or less contains a linear velocity of 4 cm / sec or more, This is a method for producing an aggregate of carbon nanotubes that is circulated at 15 cm / sec or less and is brought into contact with a catalyst at 500 to 1200 ° C.
  • an aggregate of double-walled carbon nanotubes having a low volume resistivity, high quality, and good dispersibility can be obtained.
  • the molded article, composition and conductive composite obtained from the carbon nanotube aggregate of the present invention exhibit good performance.
  • FIG. 1 shows a state in which the catalyst exists uniformly in the cross section of the reaction tube.
  • FIG. 2 is a schematic view of the vertical fluidized bed apparatus used in the examples.
  • FIG. 3 is a high-resolution transmission electron micrograph of the carbon nanotubes obtained in Example 1.
  • 4 is a Raman spectroscopic analysis chart of the carbon nanotubes obtained in Example 1.
  • FIG. 1 shows a state in which the catalyst exists uniformly in the cross section of the reaction tube.
  • FIG. 2 is a schematic view of the vertical fluidized bed apparatus used in the examples.
  • FIG. 3 is a high-resolution transmission electron micrograph of the carbon nanotubes obtained in Example 1.
  • 4 is a Raman spectroscopic analysis chart of the carbon nanotubes obtained in Example 1.
  • the aggregate of carbon nanotubes means an aggregate of a plurality of carbon nanotubes.
  • the existence form of the carbon nanotube is not particularly limited, and the carbon nanotubes may be present independently, in the form of a bundle or entanglement, or in a mixed form thereof. Further, carbon nanotubes having various numbers of layers and diameters may be included. Moreover, even when it is contained in the composition containing another component or in the composite, it is sufficient that a plurality of carbon nanotubes are contained. Further, impurities (for example, a catalyst) derived from the carbon nanotube production method may be included.
  • the aggregate of carbon nanotubes has a volume resistivity of 1 ⁇ 10 ⁇ 4 ⁇ ⁇ cm or more and 1 ⁇ 10 ⁇ 2 ⁇ ⁇ cm or less.
  • This volume resistivity can be calculated by preparing a carbon nanotube film as follows, measuring the surface resistance value of the film by the four-terminal method, and then multiplying the surface resistance value by the film thickness of the carbon nanotube film. .
  • the surface resistance value can be measured by, for example, Loresta EP MCP-T360 (manufactured by Dia Instruments Co., Ltd.) using a four-terminal four-probe method according to JISK7149.
  • When measuring high resistance it can be measured using, for example, Hiresta UP MCP-HT450 (Dia Instruments, 10 V, 10 seconds).
  • a carbon nanotube film for resistance value measurement can be produced by drying the filtered material together with the filter and the filter used for filtering at 60 ° C. for 2 hours.
  • the thickness of the produced carbon nanotube film can be measured by peeling it from the filter with tweezers. If the carbon nanotube film cannot be peeled off, measure the total thickness of the filter and carbon nanotube film, The thickness may be calculated by subtracting from the total thickness.
  • a membrane filter As a filter for filtration, a membrane filter (OMNIPOREMBRANE FILTERS, FILTER TYPE: 1.0 ⁇ m JA, 47 mm ⁇ ) can be preferably used.
  • the pore size of the filter may be 1.0 ⁇ m or less as long as the filtrate passes through.
  • the material of the filter needs to be a material that does not dissolve in NMP and ethanol, and it is preferable to use a filter made of fluororesin (PTFE).
  • the carbon nanotubes contained in the aggregate of carbon nanotubes of the present invention are 50% or more double-walled carbon nanotubes.
  • the content of the double-walled carbon nanotube is evaluated by the number of double-walled carbon nanotubes in 100 arbitrary carbon nanotubes contained in the carbon nanotube aggregate when the carbon nanotube aggregate is observed with a transmission electron microscope.
  • the carbon nanotube aggregate is observed with a transmission electron microscope at a magnification of 400,000, and a layer of 100 carbon nanotubes arbitrarily extracted from a field of view in which 10% or more of the field area is a carbon nanotube in a 75 nm square field of view. Evaluate the number. When 100 lines cannot be measured in one field of view, measurement is performed from a plurality of fields until 100 lines are obtained.
  • one carbon nanotube is counted as one if a part of the carbon nanotube is visible in the field of view, and both ends are not necessarily visible.
  • it may be connected outside the field of view and become one, but in that case, it is counted as two.
  • carbon nanotubes have a higher degree of graphitization as the number of layers decreases, that is, they have higher conductivity, and the degree of graphitization tends to decrease as the number of layers increases. Since the double-walled carbon nanotube has more layers than the single-walled carbon nanotube, the durability is high. In addition, double-walled carbon nanotubes have a high degree of graphitization and are therefore highly conductive. Therefore, the larger the proportion of double-walled carbon nanotubes, the better. In the aggregate of carbon nanotubes of the present invention, the ratio of the double-walled carbon nanotubes when measured by the above method needs to be 50% or more, that is, 50 or more out of 100, and 60 or more out of 100 must be 2 or more. Single-walled carbon nanotubes are preferable, and 70 or more of 100 are more preferably double-walled carbon nanotubes.
  • the quality of the carbon nanotube aggregate can be evaluated by a Raman G / D ratio.
  • Raman G / D ratio when evaluating the Raman G / D ratio, Raman spectroscopic analysis is performed at a wavelength of 532 nm. The higher the G / D ratio is, the better, but if it is 30 or more, it can be said to be a high quality carbon nanotube aggregate.
  • the G / D ratio is preferably 200 or less.
  • the G / D ratio is preferably 40 or more and 200 or less, more preferably 50 or more and 150 or less.
  • solid Raman spectroscopy such as aggregates of carbon nanotubes may vary depending on sampling.
  • the Raman shift observed in the vicinity of 1590 cm ⁇ 1 in the Raman spectrum obtained by the Raman spectroscopic analysis is called a graphite-derived G band
  • the Raman shift observed in the vicinity of 1350 cm ⁇ 1 is D derived from defects in amorphous carbon or graphite. Called a band. It is shown that the higher the ratio of the G band and the D band, that is, the higher the G / D ratio, the higher the degree of graphitization and the higher the quality.
  • the combustion peak temperature of the carbon nanotube aggregate of the present invention is required to be 550 ° C. or higher and 700 ° C. or lower. Preferably they are 560 degreeC or more and 650 degrees C or less.
  • the combustion peak temperature here is measured by a differential thermal analyzer.
  • a differential thermal analyzer for example, a differential thermal / thermogravimetric analyzer DTG-60A manufactured by Shimadzu Corporation can be used. Place a sample of ⁇ -alumina as a reference and about 1-10 mg each in a platinum pan in a differential thermal analyzer, and weigh it in air at a rate of 10 ° C / min. By doing so, the combustion peak temperature of the sample can be measured.
  • the combustion peak temperature is considered to correlate with the quality, diameter and bundle thickness of the carbon nanotube.
  • combustion is thought to be an oxidation reaction due to the attack of oxygen molecules, so if the degree of graphitization of carbon nanotubes is low, or if there are many defects in the graphene sheets that make up the carbon nanotubes, The combustion peak temperature is lowered.
  • carbon nanotubes having a large diameter usually have a tendency to lower the degree of graphitization, and therefore the combustion peak temperature is lowered.
  • the carbon nanotubes with a small diameter usually form a bundle. Even if each one is the same carbon nanotube, if the bundle is thick, the carbon nanotubes inside the bundle are not easily attacked by oxygen, so the combustion peak temperature of the aggregate of carbon nanotubes rises. On the contrary, when the bundle is thinned, the carbon nanotubes inside the bundle are also easily subjected to oxygen attack, so that the combustion peak temperature of the carbon nanotube aggregate is lowered.
  • the aggregate of carbon nanotubes having a combustion peak temperature higher than 700 ° C. is high in quality and thin in diameter, but the bundle is thick and it is difficult to dissociate the bundle, so that it is difficult to disperse in a solvent or resin.
  • An aggregate of carbon nanotubes having a combustion peak temperature lower than 550 ° C. has poor quality, that is, has a low degree of graphitization, and therefore does not improve its characteristics when deployed in various applications. From the above points, the combustion peak temperature is preferably in the above range in terms of quality and dispersibility.
  • the proportion of three or more layers of carbon nanotubes contained in the carbon nanotube aggregate is 10% or less.
  • the heat resistance increases as the number of carbon nanotube layers increases. Therefore, even if the carbon nanotube aggregate contains single-walled carbon nanotubes or amorphous carbon with low heat resistance, these can be selectively oxidized and removed by the vapor phase oxidation method described later, The purity of the double-walled carbon nanotube can be improved. However, if the carbon nanotube aggregate contains a large amount of three or more layers of carbon nanotubes, it is difficult to selectively remove them from the double-walled carbon nanotubes.
  • the ratio of the multi-walled carbon nanotubes having three or more layers in the carbon nanotube aggregate is preferably 10% or less. More preferably, it is 8% or less.
  • the content of the three or more carbon nanotubes is also evaluated by the number of the three or more carbon nanotubes in any 100 carbon nanotubes in the aggregate of carbon nanotubes, as described above.
  • the ratio of oxygen atoms to carbon atoms in the carbon nanotube aggregate of the present invention is preferably less than 4% (atomic%).
  • the ratio of oxygen atoms to carbon atoms can be measured by using surface composition analysis of X-ray photoelectron spectroscopy (XPS). For example, measurement can be performed using conditions of excitation X-ray: Monochromatic AlK ⁇ 1,2 line, X-ray diameter: 1000 ⁇ m, photoelectron escape angle: 90 ° (detector inclination with respect to the sample surface).
  • the ratio of oxygen atoms to carbon atoms being less than 4% means that the ratio of oxygen atoms to carbon atoms is less than 4% (atomic%) as a result of surface composition analysis by X-ray photoelectron spectroscopy (XPS).
  • the carbon nanotube aggregate is of high quality.
  • a large proportion of oxygen atoms means that there are many oxygen atom-containing functional groups (C ⁇ O, C—O, etc.), indicating that there are many defects in the graphite structure of carbon nanotubes.
  • the fact that the ratio of oxygen atoms to carbon atoms is small indicates that there are few oxygen atom-containing functional groups (C ⁇ O, C—O, etc.) introduced into the carbon nanotube. More preferably, the ratio of oxygen atoms to carbon atoms is 3% (atomic%) or less.
  • the aggregate of carbon nanotubes of the present invention preferably has a weight loss rate from 200 ° C. to 400 ° C. of 5% or less in thermogravimetry when the temperature is raised at 10 ° C./min.
  • the weight reduction rate from 200 ° C. to 400 ° C. in thermogravimetry when the temperature is raised at 10 ° C./min can be measured by thermal analysis of the carbon nanotube aggregate in the atmosphere.
  • a sample of about 1 mg is placed in a thermogravimetric analyzer (for example, a differential thermal / thermogravimetric analyzer DTG-60A manufactured by Shimadzu Corporation), and is heated from room temperature to 900 ° C. at a heating rate of 10 ° C./min. The temperature is raised to ° C.
  • the weight loss between 200 ° C. and 400 ° C. and the weight loss between 200 ° C. and 900 ° C. are measured, and the weight between 200 ° C. and 400 ° C. with respect to the weight loss between 200 ° C. and 900 ° C.
  • the rate of reduction is the weight reduction rate.
  • carbon impurities other than carbon nanotubes such as amorphous carbon
  • the weight loss rate from 200 ° C. to 400 ° C. increases as the carbon impurity increases.
  • the larger the amount of carbon impurities the lower the characteristics of the carbon nanotube aggregate.
  • the concentration of methane is preferably 10% by volume or less with respect to the entire raw material gas used in the reaction.
  • the volume% said here can be shown by the volume% of gas measured at 10125 Pa (1 atm) and 25 degreeC.
  • methane is a hardly decomposable gas, it was usual to distribute methane at a high concentration in order to increase the yield.
  • high-concentration methane is allowed to flow at a heating temperature, a large amount of by-products such as amorphous carbon is generated due to vapor phase decomposition of methane itself and side reactions on the catalyst.
  • the concentration of methane in the raw material gas is more preferably 7% by volume or less, and further preferably 5% by volume or less. Since the lower limit of explosion of methane is 5% by volume or less, if it is within this range, it is not necessary to provide an excessive safety device or the like in the reaction apparatus, so mass production is easy. However, if the concentration of methane is too dilute, the production efficiency of carbon nanotubes is lowered. Therefore, the concentration of methane in the raw material gas is preferably 1% by volume or more.
  • methane is used for the reaction with the diluent gas.
  • the diluent gas is not particularly limited, but a gas other than oxygen gas is preferably used.
  • Oxygen is not usually used because it may explode, but it may be used if it is outside the explosion range.
  • Nitrogen, argon, hydrogen, helium, neon, etc. are preferably used as the dilution gas.
  • Hydrogen is preferable because it is effective in activating the catalytic metal.
  • a gas having a large molecular weight such as argon has a large annealing effect and is preferable for the purpose of annealing.
  • nitrogen and argon are particularly preferable.
  • the linear velocity of the source gas containing methane is 4 cm / sec or more and 15 cm / sec or less.
  • methane is a hardly decomposable gas
  • a large amount of by-products such as amorphous carbon is generated by vapor phase decomposition of methane itself or side reaction on the catalyst.
  • the linear velocity of the source gas is more preferably 4 cm / sec or more and 10 cm / sec or less, and further preferably 4 cm / sec or more and 9 cm / sec or less.
  • the catalyst greatly fluctuates, deviates from the reaction temperature range (soaking zone), and a high-quality carbon nanotube aggregate cannot be obtained.
  • the temperature at which the catalyst and the raw material gas are brought into contact is 500 to 1200 ° C, more preferably 700 ° C to 1000 ° C, and still more preferably 750 ° C to 950 ° C.
  • the temperature is lower than 500 ° C.
  • the yield of the carbon nanotube aggregate is deteriorated.
  • the temperature is higher than 1200 ° C.
  • the material of the reactor to be used is restricted, and bonding between the carbon nanotubes starts, making it difficult to control the shape of the carbon nanotubes.
  • the reactor may be brought to the reaction temperature while the raw material gas is in contact with the catalyst, or the supply of the raw material gas may be started after the reactor is brought to the reaction temperature after completion of the pretreatment by heat.
  • the catalyst may be pretreated with heat before the reaction for generating the carbon nanotube aggregate.
  • the time and temperature of heat pretreatment are not particularly limited. By performing the pretreatment with heat, the catalyst may be brought into a more active state. At this time, it is also possible to flow gas.
  • As the gas nitrogen, argon, hydrogen, helium, neon or the like is preferably used. Hydrogen is preferable because it is effective in activating the catalytic metal.
  • a gas having a large molecular weight such as argon has a large annealing effect and is preferable for the purpose of annealing. Nitrogen and / or argon are particularly preferable.
  • the pretreatment with heat and the reaction for generating the carbon nanotube aggregate be performed under reduced pressure or atmospheric pressure.
  • the reaction system can be reduced in pressure with a vacuum pump or the like.
  • the reaction system is not particularly limited, but the reaction is preferably carried out using a vertical fluidized bed reactor.
  • the vertical fluidized bed reactor is a reactor installed so that methane flows in the vertical direction (hereinafter also referred to as “longitudinal direction”). Methane flows in the direction from one end of the reactor toward the other end and passes through the catalyst layer.
  • a reactor having a tube shape can be preferably used.
  • the vertical direction includes a direction having a slight inclination angle with respect to the vertical direction (for example, 90 ° ⁇ 15 °, preferably 90 ° ⁇ 10 ° with respect to the horizontal plane). Preferred is the vertical direction.
  • the supply part and the discharge part of methane do not necessarily need to be the end part of the reactor, and methane may flow in the above direction and pass through the catalyst layer in the flow process.
  • the catalyst is in a state of being present in the entire horizontal cross-sectional direction of the reactor in the vertical fluidized bed reactor, and a fluidized bed is formed during the reaction. By doing in this way, a catalyst and methane can be made to contact effectively.
  • a horizontal reactor in order to effectively bring the catalyst into contact with methane, in order to make it exist in the entire cross section of the reactor in a direction perpendicular to the flow of methane, the catalyst is viewed from the left and right due to gravity. It is necessary to pinch.
  • the carbon nanotube aggregate formation reaction the carbon nanotube aggregate is generated on the catalyst as the reaction proceeds, and the volume of the catalyst is increased. Therefore, the method of sandwiching the catalyst from the left and right is not preferable.
  • the reactor is set to a vertical type, a stage through which gas can permeate is installed in the reactor, and the catalyst is placed on the reactor, so that the catalyst can be evenly distributed in the cross-sectional direction of the reactor without sandwiching the catalyst from both sides.
  • a catalyst can be present, and a fluidized bed can also be formed when methane is passed in the vertical direction.
  • the state in which the catalyst is present on the entire surface in the horizontal sectional direction of the vertical fluidized bed reactor refers to a state in which the catalyst spreads throughout the horizontal sectional direction and the platform at the bottom of the catalyst cannot be seen. As a preferable embodiment in such a state, for example, there are the following modes.
  • FIG. 1A is a conceptual diagram showing a state in which a stand 2 on which a catalyst is placed is installed in a reactor 1 and a catalyst 3 is present on the entire horizontal cross-sectional direction of the reactor.
  • FIG. 1 (b) is a conceptual diagram showing a state in which a platform 2 on which a catalyst is placed is installed in the reactor 1, and a mixture 4 of an object other than the catalyst and the catalyst exists on the entire cross-sectional direction of the reactor. It is.
  • FIG. 1C is a conceptual diagram showing a catalyst state in which the catalyst 5 sprayed from the upper part of the reactor 1 spreads over the entire horizontal cross-sectional direction of the reactor.
  • the vertical fluidized bed reactor there are a mode in which the catalyst as described above C is dropped from the upper part of the reactor by spraying or a mode in which a catalyst generally called a boiling bed type flows (a method according to the above A and B). Can be mentioned.
  • the fluidized bed reactor can continuously synthesize by continuously supplying the catalyst and continuously removing the aggregate including the catalyst and the carbon nanotube aggregate after the reaction. It is preferable because it can be obtained efficiently.
  • the raw material methane and the catalyst are in uniform and efficient contact with each other, so that the carbon nanotube synthesis reaction is performed uniformly, the catalyst coating with impurities such as amorphous carbon is suppressed, and the catalyst activity is long. It is thought to continue.
  • a horizontal reactor In contrast to a vertical reactor, a horizontal reactor has a laterally (horizontal) reactor in which a catalyst placed on a quartz plate is placed, and methane passes over the catalyst. It refers to a reaction device in a mode of contacting and reacting. In this case, carbon nanotubes are generated on the catalyst surface, but hardly react because methane does not reach the inside of the catalyst. On the other hand, in the vertical reactor, the raw material methane can be brought into contact with the entire catalyst, so that a large amount of carbon nanotube aggregates can be efficiently synthesized.
  • the reactor is preferably heat resistant, and is preferably made of a heat resistant material such as quartz or alumina.
  • the catalyst in the present invention contains a catalytic metal.
  • the type of the catalyst metal is not particularly limited, but a metal of group 3 to 12, preferably a metal of group 5 to 11, is preferably used. Among these, V, Mo, Mn, Fe, Co, Ni, Pd, Pt, Rh, W, Cu and the like are preferable. More preferred are Fe, Co and Ni, and most preferred is Fe.
  • the metal is not necessarily a zero-valent state. Although it can be presumed that the metal is in a zero-valent state during the reaction, it may be a compound or metal species containing a wide variety of metals.
  • organic salts or inorganic salts such as formate, acetate, trifluoroacetate, ammonium citrate, nitrate, sulfate, halide salt, complex salts such as ethylenediaminetetraacetate complex and acetylacetonate complex are used. It is done.
  • the catalyst metal is preferably fine particles. The particle diameter of the fine particles is preferably 0.5 to 10 nm. If the catalytic metal is fine, carbon nanotubes with a small outer diameter are likely to be generated. Only one type of catalyst metal may be used, or two or more types may be used. When two or more kinds of catalyst metals are used, it is particularly preferable to include Fe.
  • the catalyst metal may be in a state of being supported on a carrier.
  • the carrier is not particularly limited, but a carrier selected from silica, alumina, magnesia, titania and zeolite is preferably used. Among these, magnesia is particularly preferable.
  • magnesia a commercially available product may be used, or a synthesized product may be used.
  • magnesium metal is heated in air, magnesium hydroxide is heated to 850 ° C. or higher, and magnesium carbonate 3MgCO 3 .Mg (OH) 2 .3H 2 O is heated to 950 ° C. or higher. There are methods.
  • the method for supporting the catalyst metal on the carrier is not particularly limited.
  • a carrier is impregnated in a non-aqueous solution (for example, ethanol solution) or an aqueous solution in which a catalyst metal salt to be supported is dissolved, sufficiently dispersed and mixed by stirring or ultrasonic irradiation, and then dried (impregnation method).
  • heating may be performed at a high temperature (300 to 1000 ° C.) in a gas selected from air, oxygen, nitrogen, hydrogen, an inert gas, and a mixed gas thereof or in a vacuum.
  • the optimum catalyst metal loading varies depending on the pore volume, outer surface area, and loading method of magnesia, but it is preferable to load 0.1 to 20% by weight of catalyst metal with respect to magnesia. When two or more kinds of catalyst metals are used, the ratio is not limited.
  • the contact efficiency between the catalyst and methane is improved, and more high-quality carbon nanotubes are synthesized efficiently and in large quantities. Is possible.
  • the bulk density of the catalyst is less than 0.30 g / mL, it is difficult to handle the catalyst.
  • the catalyst may be greatly swollen in the vertical reactor when contacting with methane, and the catalyst may be out of the soaking zone of the reactor to obtain high-quality carbon nanotubes. Becomes difficult.
  • the bulk density of the catalyst exceeds 2.00 g / mL, it will be difficult for the catalyst and methane to contact uniformly and efficiently, and it will also be difficult to obtain high-quality carbon nanotubes. If the bulk density of the catalyst is too large, when the catalyst is installed in a vertical reactor, the catalyst will be tightly packed, making it impossible to uniformly contact methane, making it difficult to produce high-quality carbon nanotubes. . When the bulk density of the catalyst is in the above range, the contact efficiency between methane and the catalytic metal is increased, so that uniform and high-quality carbon nanotubes can be produced efficiently and in large quantities.
  • the bulk density of the catalyst is preferably 0.30 g / mL or more and 2.00 g / mL or less.
  • the bulk density of the catalyst is more preferably 0.40 g / mL or more and 1.70 g / mL or less, and further preferably 0.50 g / mL or more and 1.50 g / mL or less.
  • Bulk density is the mass of powder per unit bulk volume.
  • the bulk density measurement method is shown below.
  • the bulk density of the powder may be affected by the temperature and humidity at the time of measurement.
  • the bulk density referred to here is a value measured at a temperature of 20 ⁇ 10 ° C. and a humidity of 60 ⁇ 10%.
  • Using a 50 mL graduated cylinder as a measuring vessel add powder to occupy a predetermined volume while tapping the bottom of the graduated cylinder. In measuring the bulk density, it is preferable to add 10 mL or more of powder.
  • the carbon nanotube production catalyst used for the measurement is 20 g ⁇ 5 g.
  • the quantity of the catalyst for carbon nanotube manufacture is less than the said quantity, it shall measure by the quantity which can be evaluated.
  • the bulk density of the catalyst is affected when the catalyst is brought into contact with methane at the heating temperature. At this time, it is unclear how the state of the catalyst changes compared to the time of catalyst preparation (before reaction). However, the bulk density of the catalyst does not change greatly before and after the reaction. Therefore, high quality carbon nanotubes can be obtained by setting the bulk density of the catalyst at the time of catalyst preparation (before reaction) within the above range.
  • the contact time between methane and the catalyst is preferably 8.0 ⁇ 10 ⁇ 2 g ⁇ min / mL or more and 1.0 ⁇ 10 0 g ⁇ min / mL or less.
  • the contact time is a value obtained by dividing the amount of catalyst (g) subjected to the reaction by the flow rate of methane (mL / min). If the contact time is too long, side reactions occur and amorphous carbon tends to increase, so 1.0 ⁇ 10 0 g ⁇ min / mL or less is preferable. Moreover, when the contact time is short, the production efficiency of carbon nanotubes deteriorates and the yield is greatly reduced. For this reason, 8.0 ⁇ 10 ⁇ 2 g ⁇ min / mL or more is preferable.
  • the aggregate of carbon nanotubes produced by the production process as described above contains impurities such as single-walled carbon nanotubes and amorphous carbon in addition to the double-walled carbon nanotubes. It is preferable to perform gas phase oxidation on the aggregate of carbon nanotubes generated as described above. By performing vapor phase oxidation, it is possible to selectively remove impurities such as amorphous carbon and single-walled carbon nanotubes having low heat resistance in the product, and the purity of the double-walled carbon nanotubes can be improved.
  • the oxidation temperature is affected by the atmospheric gas, so it is preferable to perform the baking treatment at a relatively low temperature when the oxygen concentration is high and at a relatively high temperature when the oxygen concentration is low. .
  • the firing treatment is preferably performed within the range of the combustion peak temperature of the carbon nanotube aggregate ⁇ 50 ° C. Even if the firing treatment is performed at a combustion peak temperature of less than ⁇ 50 ° C., impurities and single-walled carbon nanotubes are difficult to remove, and it is considered difficult to improve the purity of the double-walled carbon nanotubes. Further, when the baking treatment is performed at the combustion peak temperature + 50 ° C.
  • the temperature for the baking treatment is preferably selected in the range of 300 to 900 ° C., more preferably 400 to 600 ° C.
  • a lower temperature range is selected, and when the oxygen concentration is lower than the atmosphere, a higher temperature range is selected.
  • the combustion peak temperature of the carbon nanotube aggregate can be measured by thermal analysis using a differential thermal analyzer.
  • a differential thermal analyzer eg, differential thermal / thermogravimetric analyzer DTG-60A manufactured by Shimadzu Corporation
  • DTG-60A thermogravimetric analyzer
  • the firing time is not particularly limited as long as the carbon nanotube of the present invention is obtained.
  • the reaction conditions can be adjusted by, for example, lengthening the firing time when the firing temperature is low and shortening the firing time when the firing temperature is high.
  • the firing time is preferably 5 minutes to 24 hours, more preferably 10 minutes to 12 hours, and even more preferably 30 minutes to 5 hours.
  • Firing is preferably performed in the air, but may be performed in an oxygen / inert gas with a controlled oxygen concentration.
  • the oxygen concentration at this time is not particularly limited. Oxygen may be appropriately set in the range of 0.1% to 100%.
  • As the inert gas helium, nitrogen, argon or the like is used.
  • the gas phase oxidation can also be performed by a method in which oxygen or a mixed gas containing oxygen is intermittently brought into contact with the carbon nanotubes to perform a firing treatment.
  • the treatment can be performed at a relatively high temperature. This is because, since oxygen or a mixed gas containing oxygen is intermittently flowed, even if oxidation occurs, the reaction stops immediately when oxygen is consumed.
  • the temperature range is preferably about 400 to 1200 ° C., more preferably about 450 to 950 ° C. As described above, the temperature is about 500 to 1200 ° C. during the production of carbon nanotubes. Therefore, when the firing process is performed immediately after the production of the carbon nanotube, it is preferable to perform such an intermittent firing process.
  • the gas phase oxidation as described above is preferably performed until the Raman G / D ratio of the aggregate of carbon nanotubes after the gas phase oxidation at a measurement wavelength of 532 nm reaches 30 or more.
  • the Raman G / D ratio can be improved to 30 or more. Is possible.
  • the carbon nanotube aggregate of the present invention it is possible to produce a carbon nanotube molded body with extremely high conductivity.
  • a carbon nanotube molded body having very high conductivity and excellent strength can be produced.
  • the carbon nanotube molded body refers to a carbon nanotube aggregate that has been shaped by molding or processing. Molding or processing refers to all operations that pass through operations and processes that change the shape of the carbon nanotube aggregate. Examples of the carbon nanotube molded body include yarns, chips, pellets, sheets, blocks, and the like made of a carbon nanotube aggregate. A combination of these, or a result obtained by further molding or processing is also a carbon nanotube molded body.
  • the method for forming the carbon nanotube aggregate is not particularly limited.
  • the carbon nanotube aggregate sheet can be produced by dispersing the carbon nanotube aggregate in a solvent, filtering the dispersion, and drying. It is also possible to form a carbon nanotube aggregate thread by discharging a dispersion liquid in which the carbon nanotube aggregate is dispersed into a thread from a thin die and impregnating the coagulation bath.
  • the aggregate of carbon nanotubes of the present invention can be made into a composition having very high conductivity, excellent strength, or excellent thermal conductivity by mixing or dispersing in a substance other than carbon nanotubes.
  • Substances other than carbon nanotubes are, for example, resin, metal, glass, liquid dispersion medium, and the like, and may be an adhesive, cement, gypsum, ceramics, or the like.
  • the composition containing an aggregate of carbon nanotubes means all substances in a state where the aggregate of carbon nanotubes is mixed or dispersed in these substances.
  • dispersion refers to a state in which the carbon nanotubes in the carbon nanotube aggregate are loosened one by one, in a bundled state, or in a state where bundles of various thicknesses are mixed from one, It is sufficient that the nanotubes are evenly dispersed in the substance.
  • the mixed state here refers to a state in which the carbon nanotube aggregates are scattered unevenly in the substance, or simply a mixture of the solid carbon nanotube aggregate and the solid substance. Is also included.
  • each component in the composition is as follows. That is, the composition containing the aggregate of carbon nanotubes preferably contains 0.01% by weight or more of carbon nanotubes, and more preferably contains 0.1% by weight or more.
  • the upper limit of the content is preferably 20% by weight or less. When the content of the carbon nanotubes exceeds 20% by weight, it may be difficult to handle the composition.
  • the content of carbon nanotubes is more preferably 5% by weight or less, still more preferably 2% by weight or less.
  • a molded article made of a composition containing an aggregate of carbon nanotubes is a molded article that has been molded or processed by operations such as compression, cutting, crushing, stretching, and punching among solid compositions. It is the one that has been solidified again in a specific form after melting.
  • the resin is not particularly limited as long as it can mix or disperse the carbon nanotube aggregate of the present invention, and may be a natural resin or a synthetic resin.
  • a thermosetting resin or a thermoplastic resin can be suitably used as the synthetic resin.
  • a composition in which a substance other than carbon nanotubes is a thermoplastic resin is preferable because the obtained molded article has excellent impact strength and can be subjected to press molding and injection molding with high molding efficiency.
  • thermosetting resin is not particularly limited.
  • unsaturated polyester resin vinyl ester resin, epoxy resin, cyanate ester resin, benzoxazine resin, phenol (resole type) resin, urea melamine resin, thermosetting polyimide, These copolymers, modified products thereof, or resins obtained by blending two or more of them can be used. Further, in order to further improve impact resistance, a resin obtained by adding a flexible component such as elastomer, synthetic rubber, natural rubber or silicone to the thermosetting resin may be used.
  • thermoplastic resin is not particularly limited.
  • polyester resins such as liquid crystal polyester and non-liquid crystal polyester
  • polyolefins such as polyethylene, polypropylene, and polybutylene
  • styrene resins polyoxymethylene, polyamide, polycarbonate resin, Polymethylene methacrylate, polyvinyl chloride, polyphenylene sulfide resin, polyphenylene ether, polyamide resin, thermoplastic polyimide, polyamideimide, polyetherimide, polysulfone, polyethersulfone, polyketone, polyetherketone, polyetherketoneketone, Polyarylate, polyether nitrile, phenol (novolak type, etc.) resin, phenoxy resin, polytetrafluoroethylene, etc.
  • Fluorine-based resins polystyrene-based, polyolefin-based, polyurethane-based, polyester-based, polyamide-based, polybutadiene-based, polyisoprene-based, fluorine-based thermoplastic elastomers, their copolymers, modified products, and these resins
  • examples include resins blended in two or more types.
  • a resin obtained by adding a flexible component such as another elastomer, synthetic rubber, natural rubber, or silicone to the thermoplastic resin may be used.
  • Resin may be only synthetic rubber, natural rubber, or elastomer such as silicone.
  • Other examples include polyalcohol resins typified by polyvinyl alcohol, polycarboxylic acid resins typified by polyvinyl acetate, acrylic resins such as polyacrylic acid esters, and polyacrylonitrile.
  • vinyl-based adhesives such as acrylic, silicone-based, vinyl acetate resin, vinyl ether resin, and pressure-sensitive adhesives can also be mentioned.
  • the metal aluminum, copper, silver, gold, iron, nickel, zinc, lead, tin, cobalt, chromium, titanium, tungsten, etc. can be used alone or in combination.
  • the glass include soda lime glass, lead glass, and borate glass.
  • the aggregate of carbon nanotubes can be a composition dispersed in a liquid dispersion medium (hereinafter also referred to as a carbon nanotube dispersion).
  • the carbon nanotube dispersion liquid it is also preferable to further contain an additive such as a surfactant, a conductive polymer or a non-conductive polymer.
  • an additive such as a surfactant, a conductive polymer or a non-conductive polymer. This is because the above-described surfactant and certain polymer materials are useful for improving the dispersibility and dispersion stabilization capability of carbon nanotubes.
  • the content of an additive such as a surfactant is not particularly limited, but is preferably 0.1 to 50% by weight, more preferably 0.2 to 30% by weight.
  • the mixing ratio of the additive and carbon nanotube (additive / carbon nanotube) is not particularly limited, but is preferably 0.1 to 20, more preferably 0.3 to 10 by weight.
  • the carbon nanotube dispersion of the present invention may contain additives other than carbon nanotubes, surfactants, and substances other than the dispersion medium.
  • Surfactants are classified into ionic surfactants and nonionic surfactants, but any surfactant can be used in the present invention.
  • examples of the ionic surfactant include the following surfactants. Such surfactants can be used alone or in admixture of two or more.
  • the ionic surfactant is classified into a cationic surfactant, an amphoteric surfactant and an anionic surfactant.
  • the cationic surfactant include alkylamine salts and quaternary ammonium salts.
  • amphoteric surfactants include alkylbetaine surfactants and amine oxide surfactants.
  • anionic surfactants include alkylbenzene sulfonates such as dodecylbenzene sulfonic acid, aromatic sulfonic acid surfactants such as dodecyl phenyl ether sulfonate, monosoap anionic surfactants, ether sulfate-based interfaces Activators, phosphate surfactants, carboxylic acid surfactants.
  • aromatic ionic surfactants include those that contain an aromatic ring because of their excellent dispersibility, dispersion stability, and high concentration.
  • aromatic ionic surfactants An aromatic ionic surfactant such as alkylbenzene sulfonate and dodecyl phenyl ether sulfonate is particularly preferable.
  • nonionic surfactants include the following surfactants. Such surfactants can be used alone or in admixture of two or more.
  • nonionic surfactants include sugar ester surfactants such as sorbitan fatty acid esters and polyoxyethylene sorbitan fatty acid esters, fatty acid ester surfactants such as polyoxyethylene resin acid esters and polyoxyethylene fatty acid diethyl , Polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, ether surfactants such as polyoxyethylene / polypropylene glycol, polyoxyalkylene octyl phenyl ether, polyoxyalkylene nonyl phenyl ether, polyoxyalkyl dibutyl phenyl ether, poly Oxyalkyl styryl phenyl ether, polyoxyalkyl benzyl phenyl ether, polyoxyalkyl bisphenyl ether, polyoxyalkyl Aromatic anionic surfactants such as mill phenyl ether. Of these, aromatic nonionic surfactants are preferred because of their excellent dispersibility, dispersion stability, and high
  • polymer material of the conductive polymer or non-conductive polymer examples include water-soluble polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, polystyrene sulfonate ammonium salt, polystyrene sulfonate sodium salt, carboxymethyl cellulose sodium salt (Na-CMC). ), Sugar polymers such as methyl cellulose, hydroxyethyl cellulose, amylose, cycloamylose, and chitosan.
  • conductive polymers such as polythiophene, polyethylenedioxythiophene, polyisothianaphthene, polyaniline, polypyrrole, polyacetylene, and derivatives thereof can also be used.
  • the method for producing the carbon nanotube dispersion for example, a carbon nanotube aggregate and additives, and a dispersion medium commonly used for coating production, such as a ball mill, bead mill, sand mill, roll mill, homogenizer, attritor, resolver. , A paint shaker or the like) to produce a dispersion.
  • the carbon nanotube dispersion liquid is preferably subjected to size fractionation by centrifugation, filter filtration or the like before coating. For example, by centrifuging the dispersion, undispersed carbon nanotubes, excessive amounts of additives, catalysts that may be mixed during carbon nanotube synthesis, etc. are precipitated.
  • the carbon nanotubes dispersed in the liquid can be collected in the form of a liquid. Undispersed carbon nanotubes, impurities, and the like can be removed as precipitates, whereby reaggregation of the carbon nanotubes can be prevented and the stability of the dispersion can be improved. Furthermore, in strong centrifugal force, it can isolate
  • the centrifugal force at the time of centrifugation may be 100 G or more, preferably 1000 G or more, and more preferably 10,000 G or more. Although there is no restriction
  • the filter used for filter filtration can be appropriately selected between 0.05 ⁇ m and 0.2 ⁇ m. Thereby, it is possible to remove undispersed carbon nanotubes and impurities having a relatively large size among impurities that may be mixed during synthesis of the carbon nanotubes.
  • the composition after size fractionation is prepared in the above range in anticipation of the fractionated amount.
  • the carbon nanotubes can be separated according to the length of the carbon nanotubes, the number of layers, the presence or absence of a bundle structure, and the like.
  • the liquid dispersion medium may be an aqueous solvent or a non-aqueous solvent.
  • Non-aqueous solvents include hydrocarbons (toluene, xylene, etc.), chlorine-containing hydrocarbons (methylene chloride, chloroform, chlorobenzene, etc.), ethers (dioxane, tetrahydrofuran, methyl cellosolve, etc.), ether alcohols (ethoxyethanol, methoxy) Ethoxyethanol, etc.), esters (methyl acetate, ethyl acetate, etc.), ketones (cyclohexanone, methyl ethyl ketone, etc.), alcohols (ethanol, isopropanol, phenol, etc.), lower carboxylic acids (acetic acid, etc.), amines (triethylamine, triethylamine, etc.) Methanolamine, etc.), nitrogen-containing polar solvents (N, N-dimethylformamide, nitromethan
  • the dispersion medium is preferably a solvent selected from water, alcohol, toluene, acetone, ether, and combinations thereof.
  • a solvent selected from water, alcohol, toluene, acetone, ether, and combinations thereof.
  • polar solvents such as water, alcohols and amines are preferably used.
  • a liquid thing at normal temperature as a binder so that it may mention later, itself can also be used as a dispersion medium.
  • the conductive composite of the present invention is obtained by forming a conductive layer containing the above carbon nanotube aggregate on a substrate.
  • the carbon nanotube dispersion can be used as a method for forming the conductive layer.
  • the carbon nanotube dispersion is applied by a known application method such as spray coating, dip coating, spin coating, knife coating, kiss coating, gravure coating, screen printing, inkjet printing, pad printing, other types of printing, or roll coating.
  • a method of coating on a substrate can be used.
  • the most preferred application method is roll coating.
  • the application may be performed any number of times, and two different application methods may be combined.
  • the dispersion medium of the dispersion liquid is volatile, unnecessary dispersion medium can be removed by methods such as air drying, heating, and decompression. Thereby, the carbon nanotube forms a three-dimensional stitch structure and is fixed to the base material.
  • the solvent for removing the additive is not particularly limited as long as it dissolves the additive, and may be an aqueous solvent or a non-aqueous solvent. Specifically, if it is an aqueous solvent, water and alcohols can be mentioned, and if it is a non-aqueous solvent, chloroform, acetonitrile and the like can be mentioned.
  • the amount of carbon nanotubes in the carbon nanotube composition can be increased. Further, in order to improve the conductivity with a small amount of carbon nanotubes, it is preferable that the carbon nanotubes are uniformly dispersed in the carbon nanotube composition, the bundle of carbon nanotubes is preferable, and the bundle of carbon nanotubes is loosened. More preferably, it is dispersed in a single state. The thickness of the bundle can be adjusted by changing the dispersion time of the dispersion method or the type of surfactant, conductive polymer or non-conductive polymer added as an additive.
  • the carbon nanotube dispersion can be used as a desired concentration by preparing a dispersion having a concentration higher than the desired carbon nanotube content and diluting with a solvent.
  • the concentration of carbon nanotubes may be reduced, or the carbon nanotubes may be manufactured with a low concentration from the beginning.
  • a transparent conductive composite body is obtained when a base material is a transparent base material, it is preferable.
  • a transparent substrate a film such as a PET film is particularly preferable.
  • the substrate not only a transparent substrate but also any substrate such as a colored substrate and fiber can be used.
  • the carbon nanotube dispersion liquid of the present invention can be used as an antistatic floor wall material when coated on a floor material or wall material in a clean room or the like, and can be used as an antistatic garment, mat, curtain or the like when coated on a fiber.
  • the present invention after forming a conductive layer on a substrate as described above, it is also preferable to overcoat the conductive layer with a binder material capable of forming an organic or inorganic transparent film. By overcoating, it is effective for further charge dispersion and movement.
  • the conductive composite can be obtained by containing a binder material capable of forming a transparent film in the carbon nanotube dispersion liquid, and applying to the base material, followed by heating as necessary to dry or cure the film. Can do.
  • the heating conditions at that time are appropriately set according to the binder type.
  • the binder is photocurable or radiation curable
  • the coating film is cured by irradiating the coating film with light or radiation immediately after coating, not by heat curing.
  • the radiation ionizing radiation such as electron beam, ultraviolet ray, X-ray and gamma ray can be used, and the irradiation dose is determined according to the binder type.
  • the binder material is not particularly limited as long as it is used for conductive paints.
  • Various transparent organic polymers or precursors thereof hereinafter sometimes referred to as “organic polymer binders” or inorganic polymers or A precursor thereof (hereinafter sometimes referred to as “inorganic polymer binder”) can be used.
  • the organic polymer binder may be any one of thermoplastic, thermosetting, photocurable, and radiation curable.
  • organic binders include polyolefins (polyethylene, polypropylene, etc.), polyamides (nylon 6, nylon 11, nylon 66, nylon 6, 10, etc.), polyesters (polyethylene terephthalate, polybutylene terephthalate, etc.), silicone polymers , Vinyl resins (polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polyacrylate, polystyrene derivatives, polyvinyl acetate, polyvinyl alcohol, etc.), polyketone, polyimide, polycarbonate, polysulfone, polyacetal, fluororesin, phenol resin, urea resin, Melanin resin, epoxy resin, polyurethane, cellulosic polymer, proteins (gelatin, casein, etc.), chitin, polypeptide, polysaccharide, polynucleotide, etc.
  • Polymers, and precursors of these polymers can be mentioned. These can form an organic polymer transparent film simply by evaporation of a solvent, or by heat curing or curing by light irradiation or radiation irradiation.
  • inorganic polymer binders include sols of metal oxides such as silica, tin oxide, aluminum oxide, and zirconium oxide, or hydrolyzable or thermally decomposable organophosphorus compounds and organoboron compounds that are precursors of inorganic polymers.
  • organic metal compounds such as organic silane compounds, organic titanium compounds, organic zirconium compounds, organic lead compounds, and organic alkaline earth metal compounds.
  • hydrolyzable or thermally decomposable organometallic compounds are alkoxides or partial hydrolysates thereof, lower carboxylates such as acetate, and metal complexes such as acetylacetone.
  • a glassy inorganic polymer transparent film made of an oxide or a composite oxide can be formed.
  • the inorganic polymer transparent film has high hardness, excellent scratch resistance, and high transparency.
  • the conductive layer of the conductive composite of the present invention can further include a conductive organic material other than carbon nanotubes, a conductive inorganic material, or a combination of these materials.
  • a conductive organic material include buckyball, carbon black, fullerene, various carbon nanotubes, and particles containing them.
  • Conductive inorganic materials include aluminum, antimony, beryllium, cadmium, chromium, cobalt, copper, doped metal oxide, iron, gold, lead, manganese, magnesium, mercury, metal oxide, nickel, platinum, silver, steel, Examples include titanium, zinc, and particles containing them. Preferable examples include indium tin oxide, antimony tin oxide, and mixtures thereof.
  • the conductive composite containing these conductive materials is very advantageous for charge dispersion or movement. Further, a layer containing a conductive material other than these carbon nanotubes and a layer containing carbon nanotubes may be laminated.
  • the conductive layer using the carbon nanotube aggregate of the present invention exhibits excellent transparency, when a transparent substrate is used as the substrate, the conductive composite exhibits excellent transparency.
  • the surface resistance value of the conductive composite of the present invention is preferably less than 10 5 ⁇ / ⁇ .
  • various uses of transparent conductive coating such as EMI / RFI (electromagnetic interference) shield, low visibility, polymer electronics (eg, transparent conductive layer of OLED display, EL lamp, plastic chip) Useful for.
  • the surface resistance of the conductive composite of the present invention can be easily adjusted according to various applications by controlling the film thickness of the conductive layer. For example, increasing the film thickness tends to lower the surface resistance, and reducing the film thickness tends to increase the surface resistance.
  • a conductive coating for an EMI / RFI shield is generally acceptable if the surface resistance is less than 10 4 ⁇ / ⁇ , preferably 10 1 to 10 3 ⁇ / ⁇ .
  • transparent low visibility coatings are generally acceptable if the surface resistance is less than 10 3 ⁇ / ⁇ , preferably less than 10 2 ⁇ / ⁇ .
  • the surface resistance value is usually less than 10 4 ⁇ / ⁇ , preferably in the range of 10 ⁇ 2 to 10 0 ⁇ / ⁇ .
  • the conductive composite has a surface resistance of less than about 10 4 ⁇ / ⁇ .
  • the conductive composite of the present invention preferably has a surface resistance of less than 1 ⁇ 10 5 ⁇ / ⁇ , and the light transmittance at a wavelength of 550 nm satisfies the following conditions: Transmittance / transparency of conductive composite Substrate transmittance> 0.85
  • the surface resistance is 1 ⁇ 10 2 ⁇ / ⁇ or more and less than 5 ⁇ 10 4 ⁇ / ⁇ .
  • the weight loss from 200 ° C. to 400 ° C. and the weight loss from 200 ° C. to 900 ° C. are measured, and the weight loss between 200 ° C. and 400 ° C. with respect to the weight loss from 200 ° C. to 900 ° C.
  • the percentage of quantity was calculated.
  • the measurement sample was loaded into a spectrophotometer (Hitachi U-2100), and the light transmittance at a wavelength of 550 nm was measured.
  • the surface resistance value was measured using a 4-terminal 4-probe method according to JIS K7149 (established in December 1994) and a Loresta EP MCP-T360 (manufactured by Dia Instruments Co., Ltd.). When measuring high resistance, it was measured using Hiresta UP MCP-HT450 (manufactured by Dia Instruments, 10 V, 10 seconds).
  • Example 1> (Supporting catalytic metal salt on magnesia) 2.46 g of ammonium iron citrate (Wako Pure Chemical Industries, Ltd.) was dissolved in 500 mL of methanol (Kanto Chemical Co., Ltd.). To this solution, 100 g of magnesia (manufactured by Iwatani Chemical Industry Co., Ltd.) was added and stirred at room temperature for 60 minutes, and then methanol was removed under reduced pressure conditions at a water bath temperature of 40 ° C. to 60 ° C. using an evaporator. Then, it dried for 2 hours with a 120 degreeC dryer, and obtained the solid catalyst by which the catalyst metal salt was carry
  • the reactor 100 is a cylindrical quartz tube having an inner diameter of 75 mm and a length of 1700 mm.
  • a quartz sintered plate 101 is provided at the center, an inert gas and raw material gas supply line 104 at the lower part of the quartz tube, a waste gas line 105 at the upper part, a sealed catalyst feeder 102 and a catalyst charging line 103. It has.
  • a heater 106 is provided that surrounds the circumference of the reactor so that the reactor can be maintained at an arbitrary temperature.
  • the heater 106 is provided with an inspection port 107 so that the flow state in the apparatus can be confirmed.
  • the nitrogen flow rate of the raw material gas supply line 104 was increased to 16.5 L / min, and fluidization of the solid catalyst on the quartz sintered plate was started.
  • methane was further fed to the reactor at 0.78 L / min (methane concentration: 4.5 vol%, linear velocity: 6.5 cm / sec).
  • the flow was switched to a flow of only nitrogen gas to complete the synthesis.
  • the contact time between methane and the catalyst was 1.69 ⁇ 10 ⁇ 1 g ⁇ min / mL.
  • the heating was stopped and the mixture was allowed to stand at room temperature, and the composition containing the catalyst and the carbon nanotube aggregate was taken out from the reactor.
  • the obtained carbon nanotube aggregate was subjected to the following steps.
  • the obtained carbon nanotube aggregate was subjected to thermal analysis by the method described above.
  • the combustion peak temperature was 480 ° C.
  • the obtained carbon nanotube aggregate was subjected to thermal analysis.
  • the combustion peak temperature was 664 ° C.
  • the weight reduction amount from 200 degreeC to 400 degreeC is 5% of the weight reduction amount from 200 degreeC to 900 degreeC.
  • the carbon nanotube aggregate obtained as described above was observed with a high-resolution transmission electron microscope. As shown in FIG. 3, the carbon nanotube was composed of a clean graphite layer, and the number of the carbon nanotubes was two. Was observed. Two-layer carbon nanotubes occupied 80% or more (85) of 100 carbon nanotubes. The number of carbon nanotubes in three or more layers was 10% or less (seven).
  • the filter used was OMNIPOREMBRANE FILTERS, FILTER TYPE: 1.0 ⁇ m JA, 47 mm ⁇ .
  • the obtained carbon nanotube film was measured by Loresta EP MCP-T360 (manufactured by Dia Instruments Co., Ltd.) using a four-terminal four-probe method according to JIS K7149, the surface resistance was 0.249 ⁇ / ⁇ . there were. Accordingly, the volume resistivity is 1.62 ⁇ 10 ⁇ 3 ⁇ ⁇ cm.
  • the surface composition was evaluated by X-ray photoelectron spectroscopy (XPS).
  • XPS X-ray photoelectron spectroscopy
  • the equipment used is ESCALAB 220iXL, the excitation X-ray is Monochromatic AlK ⁇ 1 , 2 and the X-ray diameter is 1000 ⁇ m.
  • the photoelectron escape angle is 90 °.
  • the ratio of oxygen atoms to carbon atoms was 2.5%.
  • a transparent conductive film was obtained by the above method.
  • Example 2 (Supporting catalytic metal salt on magnesia) In the same manner as in Example 1, the catalyst metal salt was supported on magnesia.
  • Example 1 (Synthesis of double-walled carbon nanotube) Example 1 except that the above catalyst was used to circulate nitrogen during the reaction at 11.0 L / min and methane at 0.52 L / min (methane concentration: 4.5 vol%, linear velocity: 4.3 cm / sec). Carbon nanotubes were synthesized by the same method. At this time, the contact time of methane and the catalyst was 2.54 ⁇ 10 ⁇ 1 g ⁇ min / mL. The obtained carbon nanotube aggregate was subjected to thermal analysis by the method described above. The combustion peak temperature was 475 ° C.
  • volume resistivity of carbon nanotube aggregate The volume resistivity of the carbon nanotube aggregate obtained as described above was measured in the same manner as in Example 1.
  • the carbon nanotube film had a thickness of 71.5 ⁇ m and a surface resistance value of 0.383 ⁇ / ⁇ . Accordingly, the volume resistivity is 2.74 ⁇ 10 ⁇ 3 ⁇ ⁇ cm.
  • a transparent conductive film was obtained by the above method.
  • ⁇ Comparative Example 1> (Supporting catalytic metal salt on magnesia) The same operation as in Example 1 was performed to obtain a solid catalyst.
  • volume resistivity of carbon nanotube aggregate The volume resistivity of the carbon nanotube aggregate obtained as described above was measured in the same manner as in Example 1.
  • the carbon nanotube film had a thickness of 105.5 ⁇ m and a surface resistance value of 53.45 ⁇ / ⁇ . Accordingly, the volume resistivity is 5.64 ⁇ 10 ⁇ 1 ⁇ ⁇ cm.
  • volume resistivity of carbon nanotube aggregate The volume resistivity of the carbon nanotube aggregate obtained as described above was measured in the same manner as in Example 1.
  • the carbon nanotube film had a thickness of 65.3 ⁇ m and a surface resistance value of 5.89 ⁇ / ⁇ . Therefore, the volume resistivity is 3.85 ⁇ 10 ⁇ 2 ⁇ ⁇ cm.
  • an aggregate of double-walled carbon nanotubes having a low volume resistivity, high quality, and good dispersibility can be obtained.
  • the molded product, composition and conductive composite obtained from the carbon nanotube aggregate of the present invention exhibit good performance.

Abstract

A carbon nanotube assembly satisfying all the following conditions (1)-(4): (1) the carbon nanotube assembly has a volume resistivity of not less than 1 × 10-4 Ω·cm but not more than 1 × 10-2 Ω·cm; (2) not less than 50% of the carbon nanotubes in the carbon nanotube assembly are double-walled carbon nanotubes; (3) the carbon nanotube assembly has a Raman G/D ratio of not less than 30 but not more than 200 at a measurement wavelength of 532 nm; and (4) the carbon nanotube assembly has a combustion peak temperature of not less than 550˚C but not more than 700˚C.  As a result, there can be obtained a double-walled carbon nanotube assembly having low volume resistivity, high quality and good dispersibility.

Description

カーボンナノチューブ集合体およびその製造方法Carbon nanotube aggregate and method for producing the same
　本発明は、カーボンナノチューブ集合体およびその製造方法に関する。さらに、カーボンナノチューブ集合体を含む成形体、組成物および導電性複合体にも関する。 The present invention relates to an aggregate of carbon nanotubes and a method for producing the same. Further, the present invention relates to a molded body, a composition, and a conductive composite including a carbon nanotube aggregate.
　カーボンナノチューブは実質的にグラファイトの１枚面を巻いて筒状にした形状を有しており、１層に巻いたものを単層カーボンナノチューブ、多層に巻いたものを多層カーボンナノチューブという。カーボンナノチューブは、通常、層数の少ない方が高グラファイト構造を有し、単層カーボンナノチューブは電気伝導性や熱伝導性などの特性も高いことが知られている。多層カーボンナノチューブはグラファイト化度が低いため、電気伝導性や熱伝導性が一般的に単層カーボンナノチューブにくらべて低いことも知られている。一方、多層カーボンナノチューブはグラファイト層数が多いことから、単層カーボンナノチューブと比較して、耐久性が高いことが知られている。 Carbon nanotubes have a substantially cylindrical shape formed by winding one surface of graphite. Single-walled carbon nanotubes are referred to as single-walled carbon nanotubes, and multi-walled carbon nanotubes are referred to as multi-walled carbon nanotubes. It is known that carbon nanotubes usually have a high graphite structure when the number of layers is smaller, and single-walled carbon nanotubes have high characteristics such as electrical conductivity and thermal conductivity. Since multi-walled carbon nanotubes have a low degree of graphitization, it is also known that electrical conductivity and thermal conductivity are generally lower than single-walled carbon nanotubes. On the other hand, multi-walled carbon nanotubes are known to have higher durability than single-walled carbon nanotubes because of the large number of graphite layers.
　多層カーボンナノチューブの中でも、２層カーボンナノチューブは単層カーボンナノチューブの特性と多層カーボンナノチューブの両方の特性を有しているために、種々の用途において有望な素材として注目を集めている。近年では、化学気相成長法、プラズマ法、パルスアーク法などで２層カーボンナノチューブの割合が高いカーボンナノチューブ集合体を合成できることが知られるようになってきている。 Among multi-walled carbon nanotubes, double-walled carbon nanotubes are attracting attention as promising materials in various applications because they have the characteristics of both single-walled carbon nanotubes and multi-walled carbon nanotubes. In recent years, it has become known that carbon nanotube aggregates having a high proportion of double-walled carbon nanotubes can be synthesized by chemical vapor deposition, plasma method, pulse arc method or the like.
　その中で特許文献１および非特許文献１に開示された方法は、触媒化学気相成長法により、比較的品質が良く、純度が高い２層カーボンナノチューブを製造している。しかしながら、特許文献１のカーボンナノチューブは、強固で非常に大きなバンドル構造を有しているため、１本１本のカーボンナノチューブが有しているナノ効果を発揮できず、各種用途展開が困難であると推察される。特に樹脂や溶媒への分散が非常に困難であるために、種々の用途への展開が限られる。また非特許文献１のカーボンナノチューブは、横型固定床反応器を用いて合成を行っているため、触媒への原料ガスの接触が不均一であり、高品質なカーボンナノチューブが得られていない。 Among them, the methods disclosed in Patent Document 1 and Non-Patent Document 1 produce double-walled carbon nanotubes with relatively high quality and high purity by catalytic chemical vapor deposition. However, since the carbon nanotubes of Patent Document 1 have a strong and very large bundle structure, the nano effect of each carbon nanotube cannot be exhibited, and various application developments are difficult. It is guessed. In particular, since it is very difficult to disperse in a resin or a solvent, development in various applications is limited. Further, since the carbon nanotubes of Non-Patent Document 1 are synthesized using a horizontal fixed bed reactor, the contact of the raw material gas with the catalyst is not uniform, and high-quality carbon nanotubes are not obtained.
　また特許文献２には、原料ガスであるメタンを線速が９．５×１０－３ｃｍ／ｓｅｃ以下で触媒と接触させることにより２層カーボンナノチューブを合成する方法が開示されている。比較的高品質な２層カーボンナノチューブが得られているが、ラマンＧ／Ｄ比が２０程度である。アモルファスカーボンが生成し、非常に高品質な２層カーボンナノチューブ集合体までは得られていないのが現状であった。 Patent Document 2 discloses a method for synthesizing double-walled carbon nanotubes by bringing methane as a raw material gas into contact with a catalyst at a linear velocity of 9.5 × 10 −3 cm / sec or less. Although a relatively high quality double-walled carbon nanotube is obtained, the Raman G / D ratio is about 20. At present, amorphous carbon is generated, and a very high quality double-walled carbon nanotube aggregate has not been obtained.
特開２００６－３３５６０４号公報JP 2006-335604 A ＷＯ２００７／０７４６２９WO2007 / 074629
　本発明は、上記のような事情に鑑みなされたものであり、非常に高導電性、高品質、かつ分散性が良好な２層カーボンナノチューブ集合体およびその製造方法を得ることを課題とする。 The present invention has been made in view of the above circumstances, and an object of the present invention is to obtain a double-walled carbon nanotube aggregate having very high conductivity, high quality, and good dispersibility, and a method for producing the same.
　本発明は、以下の（１）～（４）の全ての条件を満たすカーボンナノチューブ集合体である。
（１）カーボンナノチューブ集合体の体積抵抗率が１×１０－４Ω・ｃｍ以上、１×１０－２Ω・ｃｍ以下；
（２）カーボンナノチューブ集合体中のカーボンナノチューブの５０％以上が２層カーボンナノチューブ；
（３）カーボンナノチューブ集合体の測定波長５３２ｎｍにおけるラマンＧ／Ｄ比が３０以上、２００以下；
（４）カーボンナノチューブ集合体の燃焼ピーク温度が５５０℃以上、７００℃以下。 The present invention is an aggregate of carbon nanotubes that satisfies all the following conditions (1) to (4).
(1) The volume resistivity of the carbon nanotube aggregate is 1 × 10 −4 Ω · cm or more and 1 × 10 −2 Ω · cm or less;
(2) 50% or more of the carbon nanotubes in the aggregate of carbon nanotubes are double-walled carbon nanotubes;
(3) The Raman G / D ratio of the carbon nanotube aggregate at a measurement wavelength of 532 nm is 30 or more and 200 or less;
(4) The combustion peak temperature of the carbon nanotube aggregate is 550 ° C. or higher and 700 ° C. or lower.
　また本発明は、反応器中で、原料ガスと触媒を接触させることによりカーボンナノチューブ集合体を製造する方法であって、メタンを濃度１０体積％以下で含む原料ガスを線速４ｃｍ／ｓｅｃ以上、１５ｃｍ／ｓｅｃ以下で流通させ、触媒と５００～１２００℃で接触させるカーボンナノチューブ集合体の製造方法である。 The present invention is also a method for producing a carbon nanotube aggregate by contacting a raw material gas and a catalyst in a reactor, wherein the raw material gas containing methane at a concentration of 10% by volume or less contains a linear velocity of 4 cm / sec or more, This is a method for producing an aggregate of carbon nanotubes that is circulated at 15 cm / sec or less and is brought into contact with a catalyst at 500 to 1200 ° C.
　本発明によれば、体積抵抗率が低く、高品質で、かつ、分散性の良好な２層カーボンナノチューブ集合体が得られる。また、本発明のカーボンナノチューブ集合体から得られる成形体、組成物および導電性複合体は、良好な性能を発揮する。 According to the present invention, an aggregate of double-walled carbon nanotubes having a low volume resistivity, high quality, and good dispersibility can be obtained. In addition, the molded article, composition and conductive composite obtained from the carbon nanotube aggregate of the present invention exhibit good performance.
図１は反応管断面に均一に触媒が存在している状態を示す。FIG. 1 shows a state in which the catalyst exists uniformly in the cross section of the reaction tube. 図２は実施例で使用した縦型流動床装置の概略図である。FIG. 2 is a schematic view of the vertical fluidized bed apparatus used in the examples. 図３は実施例１で得られたカーボンナノチューブの高分解能透過型電子顕微鏡写真である。FIG. 3 is a high-resolution transmission electron micrograph of the carbon nanotubes obtained in Example 1. 図４は実施例１で得られたカーボンナノチューブのラマン分光分析チャートである。4 is a Raman spectroscopic analysis chart of the carbon nanotubes obtained in Example 1. FIG.
　本発明においてカーボンナノチューブ集合体とは、複数のカーボンナノチューブの集合体を意味する。カーボンナノチューブの存在形態は特に限定されず、それぞれが独立で、あるいは束状、絡まり合うなどの形態あるいはこれらの混合形態で存在していてもよい。また、種々の層数および直径のカーボンナノチューブが含まれていてもよい。また、他の成分を含む組成物中、あるいは複合体中に含まれる場合でも、複数のカーボンナノチューブが含まれていれば良い。また、カーボンナノチューブ製造法由来の不純物（例えば触媒）を含んでも良い。 In the present invention, the aggregate of carbon nanotubes means an aggregate of a plurality of carbon nanotubes. The existence form of the carbon nanotube is not particularly limited, and the carbon nanotubes may be present independently, in the form of a bundle or entanglement, or in a mixed form thereof. Further, carbon nanotubes having various numbers of layers and diameters may be included. Moreover, even when it is contained in the composition containing another component or in the composite, it is sufficient that a plurality of carbon nanotubes are contained. Further, impurities (for example, a catalyst) derived from the carbon nanotube production method may be included.
　本発明において、カーボンナノチューブ集合体は、体積抵抗率が１×１０－４Ω・ｃｍ以上、１×１０－２Ω・ｃｍ以下である。この体積抵抗率は、以下のようにカーボンナノチューブ膜を作製し、その膜の表面抵抗値を４端子法によって測定後、表面抵抗値とカーボンナノチューブ膜の膜厚を掛けることによって算出することができる。表面抵抗値はＪＩＳＫ７１４９準処の４端子４探針法を用い、例えばロレスタＥＰ　ＭＣＰ－Ｔ３６０（（株）ダイアインスツルメンツ社製）にて測定することが可能である。高抵抗測定の際は、例えばハイレスターＵＰ　ＭＣＰ－ＨＴ４５０（ダイアインスツルメンツ製、１０Ｖ、１０秒）を用いて測定することが可能である。 In the present invention, the aggregate of carbon nanotubes has a volume resistivity of 1 × 10 −4 Ω · cm or more and 1 × 10 −2 Ω · cm or less. This volume resistivity can be calculated by preparing a carbon nanotube film as follows, measuring the surface resistance value of the film by the four-terminal method, and then multiplying the surface resistance value by the film thickness of the carbon nanotube film. . The surface resistance value can be measured by, for example, Loresta EP MCP-T360 (manufactured by Dia Instruments Co., Ltd.) using a four-terminal four-probe method according to JISK7149. When measuring high resistance, it can be measured using, for example, Hiresta UP MCP-HT450 (Dia Instruments, 10 V, 10 seconds).
　カーボンナノチューブ集合体２０ｍｇをＮ－メチルピロリドン１６ｍＬと混合し、超音波ホモジナイザーを用いて、出力２０Ｗで超音波を２０分照射した後、エタノール１０ｍＬと混合し、内径３５ｍｍφのろ過器を使用することによってろ取物を得る。このろ取物をろ過器とろ取に用いたフィルターごと６０℃で２時間乾燥することによって、抵抗値測定用のカーボンナノチューブ膜を作製することができる。作製したカーボンナノチューブ膜の厚みは、ピンセットなどでフィルターから剥離して測ることもできるし、カーボンナノチューブ膜を剥離できないときは、フィルターとカーボンナノチューブ膜を併せた全体の厚みを測定後、フィルターのみの厚みを全体の厚みから差し引いて算出しても良い。ろ過用のフィルターはメンブレンフィルター（ＯＭＮＩＰＯＲＥＭＥＭＢＲＡＮＥ　ＦＩＬＴＥＲＳ、ＦＩＬＴＥＲ　ＴＹＰＥ：　１．０μｍ　ＪＡ、４７ｍｍφ）を好ましく使用することができる。フィルターの孔径は、ろ液が通過するのであれば１．０μｍ以下であっても構わない。フィルターの材質は、ＮＭＰおよびエタノールに溶解しない材質である必要があり、フッ素樹脂（ＰＴＦＥ）製のフィルターを使用するのが好ましい。 By mixing 20 mg of an aggregate of carbon nanotubes with 16 mL of N-methylpyrrolidone, using an ultrasonic homogenizer, irradiating with ultrasonic waves at an output of 20 W for 20 minutes, mixing with 10 mL of ethanol, and using a filter with an inner diameter of 35 mmφ Get filtered. A carbon nanotube film for resistance value measurement can be produced by drying the filtered material together with the filter and the filter used for filtering at 60 ° C. for 2 hours. The thickness of the produced carbon nanotube film can be measured by peeling it from the filter with tweezers. If the carbon nanotube film cannot be peeled off, measure the total thickness of the filter and carbon nanotube film, The thickness may be calculated by subtracting from the total thickness. As a filter for filtration, a membrane filter (OMNIPOREMBRANE FILTERS, FILTER TYPE: 1.0 μm JA, 47 mmφ) can be preferably used. The pore size of the filter may be 1.0 μm or less as long as the filtrate passes through. The material of the filter needs to be a material that does not dissolve in NMP and ethanol, and it is preferable to use a filter made of fluororesin (PTFE).
　本発明のカーボンナノチューブ集合体に含まれるカーボンナノチューブは、５０％以上が２層カーボンナノチューブである。２層カーボンナノチューブの含有量は、カーボンナノチューブ集合体を透過型電子顕微鏡で観測した時に、カーボンナノチューブ集合体中に含まれる任意のカーボンナノチューブ１００本中の２層カーボンナノチューブの本数で評価する。カーボンナノチューブ集合体を、透過型電子顕微鏡で４０万倍で観察し、７５ｎｍ四方の視野の中で視野面積の１０％以上がカーボンナノチューブである視野中から任意に抽出した１００本のカーボンナノチューブについて層数を評価する。一つの視野中で１００本の測定ができない場合は、１００本になるまで複数の視野から測定する。このとき、カーボンナノチューブ１本とは視野中で一部カーボンナノチューブが見えていれば１本と計上し、必ずしも両端が見えている必要はない。また視野中で２本と認識されても視野外でつながって１本となっていることもあり得るが、その場合は２本と計上する。 The carbon nanotubes contained in the aggregate of carbon nanotubes of the present invention are 50% or more double-walled carbon nanotubes. The content of the double-walled carbon nanotube is evaluated by the number of double-walled carbon nanotubes in 100 arbitrary carbon nanotubes contained in the carbon nanotube aggregate when the carbon nanotube aggregate is observed with a transmission electron microscope. The carbon nanotube aggregate is observed with a transmission electron microscope at a magnification of 400,000, and a layer of 100 carbon nanotubes arbitrarily extracted from a field of view in which 10% or more of the field area is a carbon nanotube in a 75 nm square field of view. Evaluate the number. When 100 lines cannot be measured in one field of view, measurement is performed from a plurality of fields until 100 lines are obtained. At this time, one carbon nanotube is counted as one if a part of the carbon nanotube is visible in the field of view, and both ends are not necessarily visible. In addition, even if it is recognized as two in the field of view, it may be connected outside the field of view and become one, but in that case, it is counted as two.
　通常、カーボンナノチューブは層数が少ないほどグラファイト化度が高い、つまり導電性が高く、層数が増えるほどグラファイト化度が低下する傾向がある。２層カーボンナノチューブは層数が単層カーボンナノチューブよりも多いため、耐久性が高い。また、２層カーボンナノチューブは高いグラファイト化度も併せ持つため、高導電性でもある。そのため、２層カーボンナノチューブの割合は多いほど好ましい。本発明のカーボンナノチューブ集合体では、上記方法で測定したときの２層カーボンナノチューブの割合は５０％以上、つまり１００本中５０本以上であることが必要であり、１００本中６０本以上が２層カーボンナノチューブであることが好ましく、１００本中７０本以上が２層カーボンナノチューブであることがさらに好ましい。 Generally, carbon nanotubes have a higher degree of graphitization as the number of layers decreases, that is, they have higher conductivity, and the degree of graphitization tends to decrease as the number of layers increases. Since the double-walled carbon nanotube has more layers than the single-walled carbon nanotube, the durability is high. In addition, double-walled carbon nanotubes have a high degree of graphitization and are therefore highly conductive. Therefore, the larger the proportion of double-walled carbon nanotubes, the better. In the aggregate of carbon nanotubes of the present invention, the ratio of the double-walled carbon nanotubes when measured by the above method needs to be 50% or more, that is, 50 or more out of 100, and 60 or more out of 100 must be 2 or more. Single-walled carbon nanotubes are preferable, and 70 or more of 100 are more preferably double-walled carbon nanotubes.
　カーボンナノチューブ集合体の品質は、ラマンＧ／Ｄ比で評価することが可能である。ここでラマンＧ／Ｄ比を評価するときは、波長５３２ｎｍでラマン分光分析する。Ｇ／Ｄ比は高いほど良いが、３０以上であれば高品質カーボンナノチューブ集合体と言うことができる。またＧ／Ｄ比は、２００以下が好ましい。Ｇ／Ｄ比は、好ましくは４０以上、２００以下であり、さらに好ましくは５０以上、１５０以下である。また、カーボンナノチューブ集合体のような固体のラマン分光分析法は、サンプリングによってばらつくことがある。そこで少なくとも３カ所、別の場所をラマン分光分析し、その相加平均をとるものとする。ラマン分光分析法により得られるラマンスペクトルにおいて１５９０ｃｍ－１付近に見られるラマンシフトは、グラファイト由来のＧバンドと呼ばれ、１３５０ｃｍ－１付近に見られるラマンシフトはアモルファスカーボンやグラファイトの欠陥に由来のＤバンドと呼ばれる。このＧバンド、Ｄバンドの高さの比、すなわちＧ／Ｄ比が高いカーボンナノチューブほど、グラファイト化度が高く、高品質であることを示している。 The quality of the carbon nanotube aggregate can be evaluated by a Raman G / D ratio. Here, when evaluating the Raman G / D ratio, Raman spectroscopic analysis is performed at a wavelength of 532 nm. The higher the G / D ratio is, the better, but if it is 30 or more, it can be said to be a high quality carbon nanotube aggregate. The G / D ratio is preferably 200 or less. The G / D ratio is preferably 40 or more and 200 or less, more preferably 50 or more and 150 or less. In addition, solid Raman spectroscopy such as aggregates of carbon nanotubes may vary depending on sampling. Therefore, at least three places and another place are subjected to Raman spectroscopic analysis, and an arithmetic average thereof is taken. The Raman shift observed in the vicinity of 1590 cm −1 in the Raman spectrum obtained by the Raman spectroscopic analysis is called a graphite-derived G band, and the Raman shift observed in the vicinity of 1350 cm −1 is D derived from defects in amorphous carbon or graphite. Called a band. It is shown that the higher the ratio of the G band and the D band, that is, the higher the G / D ratio, the higher the degree of graphitization and the higher the quality.
　本発明のカーボンナノチューブ集合体の燃焼ピーク温度は、５５０℃以上、７００℃以下であることが必要である。好ましくは５６０℃以上、６５０℃以下である。ここでいう燃焼ピーク温度は、示差熱分析装置にて測定されるものである。示差熱分析装置としては、例えば島津製作所製　示差熱・熱重量分析装置ＤＴＧ－６０Ａなどを用いることができる。示差熱分析装置にサンプルおよびリファレンスとしてα－アルミナを白金皿に約１～１０ｍｇずつ、それぞれ秤量したものを設置し、空気中、１０℃／分の昇温速度にて室温から９００℃まで昇温することで、サンプルの燃焼ピーク温度を測定することができる。燃焼ピーク温度は、カーボンナノチューブの品質、直径およびバンドルの太さと相関があると考えられる。すなわち、燃焼は酸素分子の攻撃による酸化反応と考えられるので、カーボンナノチューブのグラファイト化度が低いと、あるいはカーボンナノチューブを構成するグラフェンシートに欠陥が多いと、酸素分子の攻撃を受けやすくなるため、燃焼ピーク温度が低くなる。また、直径の太いカーボンナノチューブは、通常そのグラファイト化度が低くなる傾向があるため、燃焼ピーク温度が低くなる。 The combustion peak temperature of the carbon nanotube aggregate of the present invention is required to be 550 ° C. or higher and 700 ° C. or lower. Preferably they are 560 degreeC or more and 650 degrees C or less. The combustion peak temperature here is measured by a differential thermal analyzer. As the differential thermal analyzer, for example, a differential thermal / thermogravimetric analyzer DTG-60A manufactured by Shimadzu Corporation can be used. Place a sample of α-alumina as a reference and about 1-10 mg each in a platinum pan in a differential thermal analyzer, and weigh it in air at a rate of 10 ° C / min. By doing so, the combustion peak temperature of the sample can be measured. The combustion peak temperature is considered to correlate with the quality, diameter and bundle thickness of the carbon nanotube. In other words, combustion is thought to be an oxidation reaction due to the attack of oxygen molecules, so if the degree of graphitization of carbon nanotubes is low, or if there are many defects in the graphene sheets that make up the carbon nanotubes, The combustion peak temperature is lowered. In addition, carbon nanotubes having a large diameter usually have a tendency to lower the degree of graphitization, and therefore the combustion peak temperature is lowered.
　直径の細いカーボンナノチューブは、通常バンドルを形成している。１本１本は同じカーボンナノチューブであったとしても、そのバンドルが太いとバンドルの内側のカーボンナノチューブは酸素の攻撃を受けにくいために、カーボンナノチューブ集合体の燃焼ピーク温度は上昇する。逆にバンドルが細くなると、バンドルの内側のカーボンナノチューブも容易に酸素の攻撃を受けやすくなるために、カーボンナノチューブ集合体の燃焼ピーク温度が低下する。 The carbon nanotubes with a small diameter usually form a bundle. Even if each one is the same carbon nanotube, if the bundle is thick, the carbon nanotubes inside the bundle are not easily attacked by oxygen, so the combustion peak temperature of the aggregate of carbon nanotubes rises. On the contrary, when the bundle is thinned, the carbon nanotubes inside the bundle are also easily subjected to oxygen attack, so that the combustion peak temperature of the carbon nanotube aggregate is lowered.
　したがって、燃焼ピーク温度が７００℃より高いカーボンナノチューブ集合体は、品質は高く、直径は細いものの、バンドルが太いものであり、バンドルの乖離が困難なため、溶媒や樹脂への分散が困難となる。燃焼ピーク温度が５５０℃より低いカーボンナノチューブ集合体は、品質が悪い、つまりグラファイト化度が低いために、種々の用途に展開したときに特性が向上しない。以上の点から燃焼ピーク温度は上記の範囲であることが品質および分散性の点で好ましい。 Therefore, the aggregate of carbon nanotubes having a combustion peak temperature higher than 700 ° C. is high in quality and thin in diameter, but the bundle is thick and it is difficult to dissociate the bundle, so that it is difficult to disperse in a solvent or resin. . An aggregate of carbon nanotubes having a combustion peak temperature lower than 550 ° C. has poor quality, that is, has a low degree of graphitization, and therefore does not improve its characteristics when deployed in various applications. From the above points, the combustion peak temperature is preferably in the above range in terms of quality and dispersibility.
　本発明のカーボンナノチューブ集合体は、カーボンナノチューブ集合体中に含まれる３層以上のカーボンナノチューブの割合が１０％以下であることが好ましい。一般にカーボンナノチューブ層数が多くなるほど、耐熱性が上がる。従ってカーボンナノチューブ集合体中に、耐熱性が低い単層カーボンナノチューブやアモルファスカーボンが含まれても、これらは後に記載する気相酸化法により、選択的に酸化して除去することが可能であり、２層カーボンナノチューブの純度を向上することができる。しかし、カーボンナノチューブ集合体中に３層以上のカーボンナノチューブが多量に含まれると、それを２層カーボンナノチューブから選択的に除去することは困難となる。また、３層以上の多層カーボンナノチューブが多く含まれるカーボンナノチューブ集合体は、電気伝導性等の特性が大きく低下する。よってカーボンナノチューブ集合体中の３層以上の多層カーボンナノチューブの割合は１０％以下が好ましい。さらに好ましくは８％以下である。この場合の３層以上のカーボンナノチューブの含有量も、上記と同様に、カーボンナノチューブ集合体中の任意の１００本のカーボンナノチューブ中の３層以上のカーボンナノチューブの本数で評価する。 In the carbon nanotube aggregate of the present invention, it is preferable that the proportion of three or more layers of carbon nanotubes contained in the carbon nanotube aggregate is 10% or less. Generally, the heat resistance increases as the number of carbon nanotube layers increases. Therefore, even if the carbon nanotube aggregate contains single-walled carbon nanotubes or amorphous carbon with low heat resistance, these can be selectively oxidized and removed by the vapor phase oxidation method described later, The purity of the double-walled carbon nanotube can be improved. However, if the carbon nanotube aggregate contains a large amount of three or more layers of carbon nanotubes, it is difficult to selectively remove them from the double-walled carbon nanotubes. In addition, a carbon nanotube aggregate containing a large number of multi-walled carbon nanotubes having three or more layers is greatly deteriorated in characteristics such as electrical conductivity. Therefore, the ratio of the multi-walled carbon nanotubes having three or more layers in the carbon nanotube aggregate is preferably 10% or less. More preferably, it is 8% or less. In this case, the content of the three or more carbon nanotubes is also evaluated by the number of the three or more carbon nanotubes in any 100 carbon nanotubes in the aggregate of carbon nanotubes, as described above.
　本発明のカーボンナノチューブ集合体の炭素原子に対する酸素原子の割合は、４％（atomic%）未満であることが好ましい。炭素原子に対する酸素原子の割合は、Ｘ線光電子分光法（ＸＰＳ）の表面組成解析を用いることで測定できる。例えば、励起Ｘ線：Ｍｏｎｏｃｈｒｏｍａｔｉｃ　ＡｌＫα１，２線、Ｘ線径：１０００μｍ、光電子脱出角度：９０°（試料表面に対する検出器の傾き）の条件を用いて測定が可能である。炭素原子に対する酸素原子の割合が４％未満であるとは、このＸ線光電子分光法（ＸＰＳ）の表面組成解析による結果、炭素原子に対する酸素原子の割合が４％（atomic%）未満であることを示しており、該カーボンナノチューブ集合体が高品質であることを示している。酸素原子の割合が大きいということは、酸素原子含有官能基（Ｃ＝ＯやＣ－Ｏ等）が多いということであり、カーボンナノチューブのグラファイト構造に欠陥が多いことを示している。逆に炭素原子に対する酸素原子の割合が少ないということは、カーボンナノチューブに導入されている酸素原子含有官能基（Ｃ＝ＯやＣ－Ｏ等）が少ないことを示している。炭素原子に対する酸素原子の割合が３％（atomic%）以下であることが、さらに好ましい。 The ratio of oxygen atoms to carbon atoms in the carbon nanotube aggregate of the present invention is preferably less than 4% (atomic%). The ratio of oxygen atoms to carbon atoms can be measured by using surface composition analysis of X-ray photoelectron spectroscopy (XPS). For example, measurement can be performed using conditions of excitation X-ray: Monochromatic AlKα 1,2 line, X-ray diameter: 1000 μm, photoelectron escape angle: 90 ° (detector inclination with respect to the sample surface). The ratio of oxygen atoms to carbon atoms being less than 4% means that the ratio of oxygen atoms to carbon atoms is less than 4% (atomic%) as a result of surface composition analysis by X-ray photoelectron spectroscopy (XPS). The carbon nanotube aggregate is of high quality. A large proportion of oxygen atoms means that there are many oxygen atom-containing functional groups (C═O, C—O, etc.), indicating that there are many defects in the graphite structure of carbon nanotubes. Conversely, the fact that the ratio of oxygen atoms to carbon atoms is small indicates that there are few oxygen atom-containing functional groups (C═O, C—O, etc.) introduced into the carbon nanotube. More preferably, the ratio of oxygen atoms to carbon atoms is 3% (atomic%) or less.
　本発明のカーボンナノチューブ集合体は、１０℃／ｍｉｎで昇温した時の熱重量測定における２００℃から４００℃の重量減少率が５％以下であることが好ましい。１０℃／分で昇温した時の熱重量測定（Ｔｈｅｒｍｏｇｒａｖｉｍｅｔｒｙ）における２００℃から４００℃の重量減少率は、カーボンナノチューブ集合体を大気下、熱分析することで測定が可能である。熱分析するとは、約１ｍｇの試料を熱重量分析装置（例えば島津製作所製　示差熱・熱重量分析装置ＤＴＧ－６０Ａ）に設置し、空気中、１０℃／分の昇温速度にて室温から９００℃まで昇温する。その時の２００℃から４００℃の間での重量減少量と２００℃から９００℃までの重量減少量を測定し、２００℃から９００℃までの重量減少量に対する２００℃から４００℃の間での重量減少量の割合を重量減少率とする。 The aggregate of carbon nanotubes of the present invention preferably has a weight loss rate from 200 ° C. to 400 ° C. of 5% or less in thermogravimetry when the temperature is raised at 10 ° C./min. The weight reduction rate from 200 ° C. to 400 ° C. in thermogravimetry when the temperature is raised at 10 ° C./min can be measured by thermal analysis of the carbon nanotube aggregate in the atmosphere. For thermal analysis, a sample of about 1 mg is placed in a thermogravimetric analyzer (for example, a differential thermal / thermogravimetric analyzer DTG-60A manufactured by Shimadzu Corporation), and is heated from room temperature to 900 ° C. at a heating rate of 10 ° C./min. The temperature is raised to ° C. The weight loss between 200 ° C. and 400 ° C. and the weight loss between 200 ° C. and 900 ° C. are measured, and the weight between 200 ° C. and 400 ° C. with respect to the weight loss between 200 ° C. and 900 ° C. The rate of reduction is the weight reduction rate.
　一般に、アモルファスカーボンなどのカーボンナノチューブ以外の炭素不純物は４００℃以下で分解するため、炭素不純物が多いほど２００℃から４００℃での重量減少率は多くなる。通常、炭素不純物の量が多いほどカーボンナノチューブ集合体としての特性は低下する。 Generally, carbon impurities other than carbon nanotubes, such as amorphous carbon, are decomposed at 400 ° C. or lower, and the weight loss rate from 200 ° C. to 400 ° C. increases as the carbon impurity increases. Usually, the larger the amount of carbon impurities, the lower the characteristics of the carbon nanotube aggregate.
　発明者らは、反応器中で、原料ガスと触媒を接触させることによりカーボンナノチューブ集合体を製造するにあたって、メタンを濃度１０体積％以下で含む原料ガスを線速４ｃｍ／ｓｅｃ以上、１５ｃｍ／ｓｅｃ以下で流通させ、触媒と５００～１２００℃で接触させることにより、体積抵抗率が低く、高品質で、かつ、分散性の良好な２層カーボンナノチューブ集合体が得られることを見出し、本発明に到ったものである。 In the production of a carbon nanotube aggregate by bringing a raw material gas into contact with a catalyst in a reactor, the inventors have introduced a raw material gas containing methane at a concentration of 10% by volume or less at a linear velocity of 4 cm / sec to 15 cm / sec. It was found that a double-walled carbon nanotube aggregate with a low volume resistivity, high quality and good dispersibility can be obtained by circulating the following and contacting with a catalyst at 500 to 1200 ° C. It has arrived.
　本発明においてメタンの濃度は、反応で使用する原料ガス全体に対して１０体積％以下が好ましい。ここで言う体積％は１０１３２５Ｐａ（１気圧）、２５℃にて測定されたガスの体積％で示すことができる。従来のカーボンナノチューブ合成反応においては、メタンが難分解性ガスであることから、収率を上げるためにメタンを高濃度で流通させることが通常であった。しかし、高濃度メタンを加熱温度下、流通させると、メタン自身の気相分解や触媒上での副反応により、アモルファスカーボン等の副生物が多量に生成する。原料ガス中のメタンの濃度を１０体積％以下で流通させることにより、高品質なカーボンナノチューブ集合体を得ることができ、好ましい。原料ガス中のメタンの濃度は、より好ましくは７体積％以下であり、さらに好ましくは５体積％以下である。メタンの爆発下限は５体積％以下であるために、この範囲であれば、反応装置に、過大な安全装置等を設ける必要がないので量産化も行いやすい。ただしあまりにメタンの濃度が希薄すぎるとカーボンナノチューブの生成効率が低下するため、原料ガス中のメタンの濃度は、１体積％以上が好ましい。 In the present invention, the concentration of methane is preferably 10% by volume or less with respect to the entire raw material gas used in the reaction. The volume% said here can be shown by the volume% of gas measured at 10125 Pa (1 atm) and 25 degreeC. In the conventional carbon nanotube synthesis reaction, since methane is a hardly decomposable gas, it was usual to distribute methane at a high concentration in order to increase the yield. However, when high-concentration methane is allowed to flow at a heating temperature, a large amount of by-products such as amorphous carbon is generated due to vapor phase decomposition of methane itself and side reactions on the catalyst. By circulating the methane concentration in the raw material gas at 10% by volume or less, a high-quality carbon nanotube aggregate can be obtained, which is preferable. The concentration of methane in the raw material gas is more preferably 7% by volume or less, and further preferably 5% by volume or less. Since the lower limit of explosion of methane is 5% by volume or less, if it is within this range, it is not necessary to provide an excessive safety device or the like in the reaction apparatus, so mass production is easy. However, if the concentration of methane is too dilute, the production efficiency of carbon nanotubes is lowered. Therefore, the concentration of methane in the raw material gas is preferably 1% by volume or more.
　原料ガス中、メタンは希釈ガスと共に反応に供する。希釈ガスとしては、特に限定されないが、酸素ガス以外のものが好ましく使用される。酸素は爆発の可能性があるので通常使用しないが、爆発範囲外であれば使用しても構わない。希釈ガスとしては、窒素、アルゴン、水素、ヘリウム、ネオン等が好ましく使用される。水素は、触媒金属の活性化に効果があるので好ましい。また、アルゴンの如き分子量が大きいガスはアニーリング効果が大きく、アニーリングを目的とする場合には好ましい。これらの中でも、特に窒素およびアルゴンが好ましい。 In the raw material gas, methane is used for the reaction with the diluent gas. The diluent gas is not particularly limited, but a gas other than oxygen gas is preferably used. Oxygen is not usually used because it may explode, but it may be used if it is outside the explosion range. Nitrogen, argon, hydrogen, helium, neon, etc. are preferably used as the dilution gas. Hydrogen is preferable because it is effective in activating the catalytic metal. Further, a gas having a large molecular weight such as argon has a large annealing effect and is preferable for the purpose of annealing. Among these, nitrogen and argon are particularly preferable.
　メタンを含む原料ガスの線速は４ｃｍ／ｓｅｃ以上、１５ｃｍ／ｓｅｃ以下である。従来のカーボンナノチューブ合成反応においては、メタンが難分解性ガスであることから、収率を上げるために原料ガスを低線速にて流通させることが通常であった。しかし、原料ガスを低線速にて加熱温度下、流通させると、メタン自身の気相分解や触媒上での副反応によりアモルファスカーボン等の副生物が多量に生成する。原料ガスの線速を４ｃｍ／ｓｅｃ以上、１５ｃｍ／ｓｅｃ以下で流通させることにより、高品質なカーボンナノチューブ集合体を得ることができ、好ましい。原料ガスの線速は、より好ましくは４ｃｍ／ｓｅｃ以上、１０ｃｍ／ｓｅｃ以下であり、さらに好ましくは４ｃｍ／ｓｅｃ以上、９ｃｍ／ｓｅｃ以下である。１５ｃｍ／ｓｅｃより線速が速いと、触媒が大きく舞い上がり、反応温度域（均熱帯）から外れ、高品質なカーボンナノチューブ集合体が得られない。 The linear velocity of the source gas containing methane is 4 cm / sec or more and 15 cm / sec or less. In the conventional carbon nanotube synthesis reaction, since methane is a hardly decomposable gas, it has been usual to circulate the raw material gas at a low linear velocity in order to increase the yield. However, when the raw material gas is circulated at a low linear velocity at a heating temperature, a large amount of by-products such as amorphous carbon is generated by vapor phase decomposition of methane itself or side reaction on the catalyst. By circulating the source gas at a linear velocity of 4 cm / sec or more and 15 cm / sec or less, a high-quality carbon nanotube aggregate can be obtained, which is preferable. The linear velocity of the source gas is more preferably 4 cm / sec or more and 10 cm / sec or less, and further preferably 4 cm / sec or more and 9 cm / sec or less. When the linear velocity is faster than 15 cm / sec, the catalyst greatly fluctuates, deviates from the reaction temperature range (soaking zone), and a high-quality carbon nanotube aggregate cannot be obtained.
　触媒と原料ガスとを接触させる温度は、５００～１２００℃であり、より好ましくは７００℃～１０００℃の範囲、さらに好ましくは７５０℃～９５０℃の範囲である。温度が５００℃よりも低いと、カーボンナノチューブ集合体の収率が悪くなる。また温度が１２００℃よりも高いと、使用する反応器の材質に制約があると共に、カーボンナノチューブ同士の接合が始まり、カーボンナノチューブの形状のコントロールが困難になる。原料ガスを触媒に接触させながら反応器を反応温度にしてもよいし、熱による前処理終了後、反応器を反応温度にしてから、原料ガスの供給を開始しても良い。 The temperature at which the catalyst and the raw material gas are brought into contact is 500 to 1200 ° C, more preferably 700 ° C to 1000 ° C, and still more preferably 750 ° C to 950 ° C. When the temperature is lower than 500 ° C., the yield of the carbon nanotube aggregate is deteriorated. On the other hand, when the temperature is higher than 1200 ° C., the material of the reactor to be used is restricted, and bonding between the carbon nanotubes starts, making it difficult to control the shape of the carbon nanotubes. The reactor may be brought to the reaction temperature while the raw material gas is in contact with the catalyst, or the supply of the raw material gas may be started after the reactor is brought to the reaction temperature after completion of the pretreatment by heat.
　カーボンナノチューブ集合体を生成させる反応の前に、触媒に熱による前処理を行ってもよい。熱による前処理の時間および温度は、特に限定しない。熱による前処理を行うことにより、触媒をより活性な状態にできることもある。この時、ガスを流すことも可能である。ガスとしては、窒素、アルゴン、水素、ヘリウム、ネオン等が好ましく使用される。水素は、触媒金属の活性化に効果があるので好ましい。アルゴンの如き分子量が大きいガスは、アニーリング効果が大きく、アニーリングを目的とする場合には好ましい。特に窒素および／またはアルゴンが好ましい。 The catalyst may be pretreated with heat before the reaction for generating the carbon nanotube aggregate. The time and temperature of heat pretreatment are not particularly limited. By performing the pretreatment with heat, the catalyst may be brought into a more active state. At this time, it is also possible to flow gas. As the gas, nitrogen, argon, hydrogen, helium, neon or the like is preferably used. Hydrogen is preferable because it is effective in activating the catalytic metal. A gas having a large molecular weight such as argon has a large annealing effect and is preferable for the purpose of annealing. Nitrogen and / or argon are particularly preferable.
　熱による前処理、およびカーボンナノチューブ集合体を生成させる反応は、減圧もしくは大気圧で行うことが好ましい。触媒と原料ガスの接触を減圧で行う場合は、真空ポンプなどで反応系を減圧にすることができる。 It is preferable that the pretreatment with heat and the reaction for generating the carbon nanotube aggregate be performed under reduced pressure or atmospheric pressure. When the contact between the catalyst and the raw material gas is performed under reduced pressure, the reaction system can be reduced in pressure with a vacuum pump or the like.
　本発明において反応方式は特に限定しないが、縦型流動床型反応器を用いて反応させることが好ましい。縦型流動床型反応器とは、メタンが、鉛直方向（以下「縦方向」と称する場合もある）に流通するように設置された反応器である。該反応器の一方の端部から他方の端部に向けた方向にメタンが流通し、触媒層を通過する。反応器は、例えば管形状を有する反応器を好ましく用いることができる。なお、鉛直方向とは、鉛直方向に対して若干傾斜角度を有する方向をも含む（例えば水平面に対し９０°±１５°、好ましくは９０°±１０°）。好ましいのは鉛直方向である。メタンの供給部および排出部は、必ずしも反応器の端部である必要はなく、メタンが前記方向に流通し、その流通過程で触媒層を通過すればよい。 In the present invention, the reaction system is not particularly limited, but the reaction is preferably carried out using a vertical fluidized bed reactor. The vertical fluidized bed reactor is a reactor installed so that methane flows in the vertical direction (hereinafter also referred to as “longitudinal direction”). Methane flows in the direction from one end of the reactor toward the other end and passes through the catalyst layer. As the reactor, for example, a reactor having a tube shape can be preferably used. The vertical direction includes a direction having a slight inclination angle with respect to the vertical direction (for example, 90 ° ± 15 °, preferably 90 ° ± 10 ° with respect to the horizontal plane). Preferred is the vertical direction. The supply part and the discharge part of methane do not necessarily need to be the end part of the reactor, and methane may flow in the above direction and pass through the catalyst layer in the flow process.
　触媒は、縦型流動床型反応器中、反応器の水平断面方向全面に存在させた状態にあり、反応時には流動床を形成した状態とする。このようにすることにより、触媒とメタンを有効に接触させることができる。横型反応器の場合、触媒とメタンを有効に接触させるため、メタンの流れに対して垂直方向で反応器の断面全面に存在させた状態にするには、重力がかかる関係上、触媒を左右から挟み込む必要がある。しかし、カーボンナノチューブ集合体の生成反応の場合、反応するに従って触媒上にカーボンナノチューブ集合体が生成して、触媒の体積が増加するので、左右から触媒を挟みこむ方法は好ましくない。また、横型で流動床を形成させることは難しい。本発明では反応器を縦型にし、反応器内にガスが透過できる台を設置して、その上に触媒を置くことによって、触媒を両側から挟みこむことなく、反応器の断面方向に均一に触媒を存在させることができ、メタンを鉛直方向に流通させる際に流動床を形成させることもできる。触媒を縦型流動床反応器の水平断面方向全面に存在させた状態とは、水平断面方向に全体に触媒が広がっていて触媒底部の台が見えない状態を言う。このような状態の好ましい実施態様としては、例えば、次のような態様がある。 The catalyst is in a state of being present in the entire horizontal cross-sectional direction of the reactor in the vertical fluidized bed reactor, and a fluidized bed is formed during the reaction. By doing in this way, a catalyst and methane can be made to contact effectively. In the case of a horizontal reactor, in order to effectively bring the catalyst into contact with methane, in order to make it exist in the entire cross section of the reactor in a direction perpendicular to the flow of methane, the catalyst is viewed from the left and right due to gravity. It is necessary to pinch. However, in the case of the carbon nanotube aggregate formation reaction, the carbon nanotube aggregate is generated on the catalyst as the reaction proceeds, and the volume of the catalyst is increased. Therefore, the method of sandwiching the catalyst from the left and right is not preferable. Moreover, it is difficult to form a fluidized bed in a horizontal type. In the present invention, the reactor is set to a vertical type, a stage through which gas can permeate is installed in the reactor, and the catalyst is placed on the reactor, so that the catalyst can be evenly distributed in the cross-sectional direction of the reactor without sandwiching the catalyst from both sides. A catalyst can be present, and a fluidized bed can also be formed when methane is passed in the vertical direction. The state in which the catalyst is present on the entire surface in the horizontal sectional direction of the vertical fluidized bed reactor refers to a state in which the catalyst spreads throughout the horizontal sectional direction and the platform at the bottom of the catalyst cannot be seen. As a preferable embodiment in such a state, for example, there are the following modes.
　Ａ．反応器内にガスが透過できる触媒を置く台（セラミックスフィルターなど）を置き、そこに所定の厚みで触媒を充填する。この触媒層の上下が多少凸凹してもかまわない（図１（ａ））。図１（ａ）は、反応器１の中に触媒を置く台２が設置され、その上に触媒３が反応器の水平断面方向全体に存在している状態を示す概念図である。 A. A stage (ceramic filter or the like) on which a gas permeable catalyst is placed in the reactor, and the catalyst is filled therewith to a predetermined thickness. The upper and lower sides of the catalyst layer may be slightly uneven (FIG. 1 (a)). FIG. 1A is a conceptual diagram showing a state in which a stand 2 on which a catalyst is placed is installed in a reactor 1 and a catalyst 3 is present on the entire horizontal cross-sectional direction of the reactor.
　Ｂ．Ａと同様の触媒を置く台上に、触媒以外の物体（充填材）と触媒を混ぜて充填する。この触媒層は均一であることが好ましいが、上下が多少凸凹してもかまわない（図１（ｂ））。図１（ｂ）は反応器１の中に触媒を置く台２が設置され、その上に触媒以外の物体と触媒の混合物４が反応器の断面方向全体に存在している状態を示す概念図である。 B. An object (filler) other than the catalyst and the catalyst are mixed and filled on the table on which the catalyst similar to A is placed. The catalyst layer is preferably uniform, but the upper and lower sides may be somewhat uneven (FIG. 1 (b)). FIG. 1 (b) is a conceptual diagram showing a state in which a platform 2 on which a catalyst is placed is installed in the reactor 1, and a mixture 4 of an object other than the catalyst and the catalyst exists on the entire cross-sectional direction of the reactor. It is.
　Ｃ．反応器上部から触媒を噴霧などで落とし、触媒粉末がガスを介して反応器水平断面方向に均一に存在している状態（図１（ｃ））。図１（ｃ）は反応器１上部から噴霧した触媒５が反応器水平断面方向全体に広がった触媒状態を示す概念図である。縦型流動床反応器の一例としては上述Ｃのような触媒を反応器上部から噴霧などによって落とす態様や、一般に沸騰床型と言われる触媒が流動する態様（上述ＡやＢに準ずる方法）が挙げられる。 C. The catalyst is dropped from the upper part of the reactor by spraying or the like, and the catalyst powder is uniformly present in the horizontal cross-sectional direction of the reactor through the gas (FIG. 1 (c)). FIG. 1C is a conceptual diagram showing a catalyst state in which the catalyst 5 sprayed from the upper part of the reactor 1 spreads over the entire horizontal cross-sectional direction of the reactor. As an example of the vertical fluidized bed reactor, there are a mode in which the catalyst as described above C is dropped from the upper part of the reactor by spraying or a mode in which a catalyst generally called a boiling bed type flows (a method according to the above A and B). Can be mentioned.
　流動床型反応器は、触媒を連続的に供給し、反応後の触媒とカーボンナノチューブ集合体を含む集合体を連続的に取り出すことにより、連続的な合成が可能であり、カーボンナノチューブ集合体を効率よく得ることができ好ましい。 The fluidized bed reactor can continuously synthesize by continuously supplying the catalyst and continuously removing the aggregate including the catalyst and the carbon nanotube aggregate after the reaction. It is preferable because it can be obtained efficiently.
　また、流動床型反応器においては、原料のメタンと触媒が均一に効率よく接触するためにカーボンナノチューブ合成反応が均一に行われ、アモルファスカーボンなどの不純物による触媒被覆が抑制され、触媒活性が長く続くと考えられる。 In the fluidized bed reactor, the raw material methane and the catalyst are in uniform and efficient contact with each other, so that the carbon nanotube synthesis reaction is performed uniformly, the catalyst coating with impurities such as amorphous carbon is suppressed, and the catalyst activity is long. It is thought to continue.
　縦型反応器とは対照的に、横型反応器は横方向（水平方向）に設置された反応器内に、石英板上に置かれた触媒が設置され、該触媒上をメタンが通過して接触、反応する態様の反応装置を指す。この場合、触媒表面ではカーボンナノチューブが生成するが、触媒内部にはメタンが到達しないためにほとんど反応しない。これに対して、縦型反応器では触媒全体に原料のメタンが接触することが可能となるため、効率的に、多量のカーボンナノチューブ集合体を合成することが可能である。 In contrast to a vertical reactor, a horizontal reactor has a laterally (horizontal) reactor in which a catalyst placed on a quartz plate is placed, and methane passes over the catalyst. It refers to a reaction device in a mode of contacting and reacting. In this case, carbon nanotubes are generated on the catalyst surface, but hardly react because methane does not reach the inside of the catalyst. On the other hand, in the vertical reactor, the raw material methane can be brought into contact with the entire catalyst, so that a large amount of carbon nanotube aggregates can be efficiently synthesized.
　反応器は耐熱性であることが好ましく、石英製、アルミナ製等の耐熱材質からなることが好ましい。 The reactor is preferably heat resistant, and is preferably made of a heat resistant material such as quartz or alumina.
　本発明における触媒は、触媒金属を含む。触媒金属の種類は、特に限定されないが、好ましくは３～１２族の金属、特に好ましくは、５～１１族の金属が用いられる。中でも、Ｖ、Ｍｏ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｐｄ、Ｐｔ、Ｒｈ、Ｗ、Ｃｕ等が好ましい。さらに好ましくは、Ｆｅ、ＣｏおよびＮｉであり、最も好ましいのはＦｅである。ここで金属とは、０価の状態とは限らない。反応中は０価の金属状態になっていると推定できるが、広く金属を含む化合物または金属種でよい。例えば、ギ酸塩、酢酸塩、トリフルオロ酢酸塩、クエン酸アンモニウム塩、硝酸塩、硫酸塩、ハロゲン化物塩などの有機塩または無機塩、エチレンジアミン４酢酸錯体やアセチルアセトナート錯体のような錯塩などが用いられる。また触媒金属は微粒子であることが好ましい。微粒子の粒径は０．５～１０ｎｍであることが好ましい。触媒金属が微粒子であると外径の細いカーボンナノチューブが生成しやすい。触媒金属は１種類だけを使用しても、２種類以上を使用してもよい。２種類以上の触媒金属を使用する場合は、Ｆｅを含むことが特に好ましい。 The catalyst in the present invention contains a catalytic metal. The type of the catalyst metal is not particularly limited, but a metal of group 3 to 12, preferably a metal of group 5 to 11, is preferably used. Among these, V, Mo, Mn, Fe, Co, Ni, Pd, Pt, Rh, W, Cu and the like are preferable. More preferred are Fe, Co and Ni, and most preferred is Fe. Here, the metal is not necessarily a zero-valent state. Although it can be presumed that the metal is in a zero-valent state during the reaction, it may be a compound or metal species containing a wide variety of metals. For example, organic salts or inorganic salts such as formate, acetate, trifluoroacetate, ammonium citrate, nitrate, sulfate, halide salt, complex salts such as ethylenediaminetetraacetate complex and acetylacetonate complex are used. It is done. The catalyst metal is preferably fine particles. The particle diameter of the fine particles is preferably 0.5 to 10 nm. If the catalytic metal is fine, carbon nanotubes with a small outer diameter are likely to be generated. Only one type of catalyst metal may be used, or two or more types may be used. When two or more kinds of catalyst metals are used, it is particularly preferable to include Fe.
　触媒金属は、担体に担持された状態のものであっても良い。ここで担体とは特に限定されないが、シリカ、アルミナ、マグネシア、チタニアおよびゼオライトから選ばれたものが好ましく用いられる。この中でも特にマグネシアが好ましい。マグネシアは、市販品を使用しても良いし、合成したものを使用しても良い。マグネシアの好ましい製法としては、金属マグネシウムを空気中で加熱する、水酸化マグネシウムを８５０℃以上に加熱する、炭酸水酸化マグネシウム３ＭｇＣＯ３・Ｍｇ（ＯＨ）２・３Ｈ２Ｏを９５０℃以上に加熱する等の方法がある。 The catalyst metal may be in a state of being supported on a carrier. Here, the carrier is not particularly limited, but a carrier selected from silica, alumina, magnesia, titania and zeolite is preferably used. Among these, magnesia is particularly preferable. As magnesia, a commercially available product may be used, or a synthesized product may be used. As a preferable production method of magnesia, magnesium metal is heated in air, magnesium hydroxide is heated to 850 ° C. or higher, and magnesium carbonate 3MgCO 3 .Mg (OH) 2 .3H 2 O is heated to 950 ° C. or higher. There are methods.
　担体に触媒金属を担持する方法は、特に限定されない。例えば、担持したい触媒金属の塩を溶解させた非水溶液（例えばエタノール溶液）中または水溶液中に、担体を含浸し、攪拌や超音波照射などにより充分に分散混合した後、乾燥させる（含浸法）。さらに空気、酸素、窒素、水素、不活性ガスおよびそれらの混合ガスから選ばれたガス中または真空中、高温（３００～１０００℃）で加熱してもよい。 The method for supporting the catalyst metal on the carrier is not particularly limited. For example, a carrier is impregnated in a non-aqueous solution (for example, ethanol solution) or an aqueous solution in which a catalyst metal salt to be supported is dissolved, sufficiently dispersed and mixed by stirring or ultrasonic irradiation, and then dried (impregnation method). . Further, heating may be performed at a high temperature (300 to 1000 ° C.) in a gas selected from air, oxygen, nitrogen, hydrogen, an inert gas, and a mixed gas thereof or in a vacuum.
　触媒金属担持量は、多いほどカーボンナノチューブの収量が上がるが、多すぎると触媒金属の粒子径が大きくなり、生成するカーボンナノチューブが太くなる。触媒金属担持量が少ないと、担持される触媒金属の粒子径が小さくなり、外径の細いカーボンナノチューブが得られるが、収率が低くなる傾向がある。最適な触媒金属担持量は、マグネシアの細孔容量や外表面積、担持方法によって異なるが、マグネシアに対して０．１～２０重量％の触媒金属を担持することが好ましい。２種類以上の触媒金属を使用する場合、その比率は限定されない。 The greater the amount of catalyst metal supported, the higher the yield of carbon nanotubes. However, if the amount is too large, the particle diameter of the catalyst metal will increase, and the resulting carbon nanotubes will become thicker. When the amount of the catalyst metal supported is small, the particle diameter of the supported catalyst metal becomes small and carbon nanotubes with a thin outer diameter can be obtained, but the yield tends to be low. The optimum catalyst metal loading varies depending on the pore volume, outer surface area, and loading method of magnesia, but it is preferable to load 0.1 to 20% by weight of catalyst metal with respect to magnesia. When two or more kinds of catalyst metals are used, the ratio is not limited.
　触媒のかさ密度が０．３０ｇ／ｍＬ以上、２．００ｇ／ｍＬ以下であることにより、触媒とメタンとの接触効率が良くなり、よりいっそう高品質なカーボンナノチューブを効率よく、多量に合成することが可能となる。触媒のかさ密度が０．３０ｇ／ｍＬ未満では、触媒を取り扱いづらい。また、触媒のかさ密度が小さすぎると、メタンと接触させる際に、縦型反応器中で触媒が大きく舞い上がり、触媒が反応器の均熱帯を外れることがあり、高品質なカーボンナノチューブを得ることが困難になる。また触媒のかさ密度が２．００ｇ／ｍＬを超えると、触媒とメタンとが均一に効率よく接触することが困難になり、やはり高品質なカーボンナノチューブを得ることが困難になる。触媒のかさ密度が大きすぎる場合、縦型反応器に触媒を設置した際、触媒が密に詰まってしまうためメタンと均一に接触ができず、高品質なカーボンナノチューブを生成することが困難になる。触媒のかさ密度が上記の範囲であると、メタンと触媒金属との接触効率が上がるため、均一で高品質なカーボンナノチューブを効率よく、かつ、多量に製造することが可能となる。また、触媒のかさ密度が大きすぎる場合、流動床中で触媒が動きにくいために、メタンは、触媒層の最も通りやすい箇所だけを通ってしまうという、いわゆるショートパスの問題が生じる。触媒のかさ密度が上記の範囲であると、触媒が動くことによって、固定されたショートパスができにくい。よって触媒のかさ密度は０．３０ｇ／ｍＬ以上、２．００ｇ／ｍＬ以下が好ましい。触媒のかさ密度は、より好ましくは０．４０ｇ／ｍＬ以上、１．７０ｇ／ｍＬ以下であり、さらに好ましくは０．５０ｇ／ｍＬ以上、１．５０ｇ／ｍＬ以下である。 When the bulk density of the catalyst is 0.30 g / mL or more and 2.00 g / mL or less, the contact efficiency between the catalyst and methane is improved, and more high-quality carbon nanotubes are synthesized efficiently and in large quantities. Is possible. When the bulk density of the catalyst is less than 0.30 g / mL, it is difficult to handle the catalyst. In addition, if the bulk density of the catalyst is too small, the catalyst may be greatly swollen in the vertical reactor when contacting with methane, and the catalyst may be out of the soaking zone of the reactor to obtain high-quality carbon nanotubes. Becomes difficult. On the other hand, if the bulk density of the catalyst exceeds 2.00 g / mL, it will be difficult for the catalyst and methane to contact uniformly and efficiently, and it will also be difficult to obtain high-quality carbon nanotubes. If the bulk density of the catalyst is too large, when the catalyst is installed in a vertical reactor, the catalyst will be tightly packed, making it impossible to uniformly contact methane, making it difficult to produce high-quality carbon nanotubes. . When the bulk density of the catalyst is in the above range, the contact efficiency between methane and the catalytic metal is increased, so that uniform and high-quality carbon nanotubes can be produced efficiently and in large quantities. Further, when the bulk density of the catalyst is too large, the catalyst is difficult to move in the fluidized bed, so that a problem of so-called short path that methane passes only through the most easily passing part of the catalyst layer occurs. When the bulk density of the catalyst is within the above range, it is difficult to form a fixed short path due to the movement of the catalyst. Therefore, the bulk density of the catalyst is preferably 0.30 g / mL or more and 2.00 g / mL or less. The bulk density of the catalyst is more preferably 0.40 g / mL or more and 1.70 g / mL or less, and further preferably 0.50 g / mL or more and 1.50 g / mL or less.
　かさ密度とは単位かさ体積あたりの粉体質量のことである。以下にかさ密度の測定方法を示す。粉体のかさ密度は、測定時の温度、湿度に影響されることがある。ここで言うかさ密度は、温度２０±１０℃、湿度６０±１０％で測定したときの値である。５０ｍＬメスシリンダーを測定容器として用い、メスシリンダーの底を軽く叩きながら、予め定めた容積を占めるように粉末を加える。かさ密度の測定に際しては１０ｍＬ以上の粉末を加えることが好ましい。その後、メスシリンダーの底を床面１ｃｍの高さから落とすことを２０回繰り返した後、目視にて粉末が占める容積値の変化率が±０．２ｍＬ以内であることを確認し、詰める操作を終了する。もし容積値に目視にて±０．２ｍＬ以上の変化があれば、メスシリンダーの底を軽く叩きながら粉末を追加し、再度メスシリンダーの底を床面１ｃｍの高さから落とすことを２０回繰り返し、目視にて粉末が占める容積値に±０．２ｍＬ以上の変化がないことを確認して操作を終了する。上記の方法で詰めた一定量の粉末の重量を求めることを３回繰り返し、その平均重量を粉末が占める容積で割った値（＝重量（ｇ）／体積（ｍＬ））を粉末のかさ密度とする。測定に供するカーボンナノチューブ製造用触媒は、２０ｇ±５ｇとする。なお、カーボンナノチューブ製造用触媒の量が前記量に満たない場合は、評価可能な量で測定するものとする。 Bulk density is the mass of powder per unit bulk volume. The bulk density measurement method is shown below. The bulk density of the powder may be affected by the temperature and humidity at the time of measurement. The bulk density referred to here is a value measured at a temperature of 20 ± 10 ° C. and a humidity of 60 ± 10%. Using a 50 mL graduated cylinder as a measuring vessel, add powder to occupy a predetermined volume while tapping the bottom of the graduated cylinder. In measuring the bulk density, it is preferable to add 10 mL or more of powder. Then, after repeating the dropping of the bottom of the graduated cylinder from the height of 1 cm of the floor 20 times, visually confirming that the rate of change of the volume value occupied by the powder is within ± 0.2 mL, and packing it. finish. If there is a visual change of ± 0.2 mL or more in the volume value, add the powder while tapping the bottom of the graduated cylinder, and drop the bottom of the graduated cylinder from the height of 1 cm on the floor again 20 times. After confirming that there is no change of ± 0.2 mL or more in the volume value occupied by the powder, the operation is finished. The determination of the weight of a certain amount of powder packed by the above method is repeated three times, and the value obtained by dividing the average weight by the volume occupied by the powder (= weight (g) / volume (mL)) is the bulk density of the powder. To do. The carbon nanotube production catalyst used for the measurement is 20 g ± 5 g. In addition, when the quantity of the catalyst for carbon nanotube manufacture is less than the said quantity, it shall measure by the quantity which can be evaluated.
　触媒のかさ密度が影響するのは、触媒を加熱温度下にメタンと接触させるときである。このとき触媒の状態は、触媒調製時（反応前）と比較してどのように変化しているか、詳細は不明である。しかし、反応前後で触媒のかさ密度は大きく変化しない。そのため、触媒調製時（反応前）の触媒のかさ密度を上記範囲にすることで、高品質なカーボンナノチューブを得ることができる。 The bulk density of the catalyst is affected when the catalyst is brought into contact with methane at the heating temperature. At this time, it is unclear how the state of the catalyst changes compared to the time of catalyst preparation (before reaction). However, the bulk density of the catalyst does not change greatly before and after the reaction. Therefore, high quality carbon nanotubes can be obtained by setting the bulk density of the catalyst at the time of catalyst preparation (before reaction) within the above range.
　メタンと触媒の接触時間は８．０×１０－２ｇ・ｍｉｎ／ｍＬ以上、１．０×１００ｇ・ｍｉｎ／ｍＬ以下であることが好ましい。ここで接触時間とは反応に供した触媒量（ｇ）をメタンの流量（ｍＬ／ｍｉｎ）で除した値である。接触時間が長すぎると副反応が起こり、アモルファスカーボンが増える傾向にあるので、１．０×１００ｇ・ｍｉｎ／ｍＬ以下が好ましい。また接触時間が短いとカーボンナノチューブの製造効率が悪くなり、収量が大きく減少する。このため、８．０×１０－２ｇ・ｍｉｎ／ｍＬ以上が好ましい。 The contact time between methane and the catalyst is preferably 8.0 × 10 −2 g · min / mL or more and 1.0 × 10 0 g · min / mL or less. Here, the contact time is a value obtained by dividing the amount of catalyst (g) subjected to the reaction by the flow rate of methane (mL / min). If the contact time is too long, side reactions occur and amorphous carbon tends to increase, so 1.0 × 10 0 g · min / mL or less is preferable. Moreover, when the contact time is short, the production efficiency of carbon nanotubes deteriorates and the yield is greatly reduced. For this reason, 8.0 × 10 −2 g · min / mL or more is preferable.
　上記のような製造工程によって製造されたカーボンナノチューブ集合体は、２層カーボンナノチューブ以外に、単層カーボンナノチューブやアモルファスカーボンなどの不純物も含んでいる。以上のように生成したカーボンナノチューブ集合体に対して気相酸化を行うことが好ましい。気相酸化を行うことで、生成物中のアモルファスカーボンなどの不純物および耐熱性の低い単層カーボンナノチューブを選択的に除去することが可能となり、２層カーボンナノチューブの純度を向上することができる。 The aggregate of carbon nanotubes produced by the production process as described above contains impurities such as single-walled carbon nanotubes and amorphous carbon in addition to the double-walled carbon nanotubes. It is preferable to perform gas phase oxidation on the aggregate of carbon nanotubes generated as described above. By performing vapor phase oxidation, it is possible to selectively remove impurities such as amorphous carbon and single-walled carbon nanotubes having low heat resistance in the product, and the purity of the double-walled carbon nanotubes can be improved.
　気相酸化として焼成処理を行う場合、酸化温度は雰囲気ガスに影響されるため、酸素濃度が高い場合には比較的低温で、酸素濃度が低い場合には比較的高温で焼成処理することが好ましい。大気下で焼成処理を行う場合は、カーボンナノチューブ集合体の燃焼ピーク温度±５０℃の範囲内で焼成処理をすることが好ましい。燃焼ピーク温度－５０℃未満で焼成処理を行っても、不純物や単層カーボンナノチューブは除去されにくく、２層カーボンナノチューブの純度を向上させることは困難であると考えられる。また燃焼ピーク温度＋５０℃超で焼成処理を行うと、２層カーボンナノチューブまで消失してしまう。よってカーボンナノチューブ集合体の燃焼ピーク温度付近で焼成するのが好ましい。さらに好ましくは燃焼ピーク温度±３０℃の範囲である。具体的には、焼成処理の温度は、３００～９００℃の範囲で選択することが好ましく、４００～６００℃がより好ましい。酸素濃度が大気よりも高い場合はこれよりも低めの温度範囲、酸素濃度が大気よりも低い場合には高めの温度範囲を選択する。 When performing the baking treatment as vapor phase oxidation, the oxidation temperature is affected by the atmospheric gas, so it is preferable to perform the baking treatment at a relatively low temperature when the oxygen concentration is high and at a relatively high temperature when the oxygen concentration is low. . When the firing treatment is performed in the air, the firing treatment is preferably performed within the range of the combustion peak temperature of the carbon nanotube aggregate ± 50 ° C. Even if the firing treatment is performed at a combustion peak temperature of less than −50 ° C., impurities and single-walled carbon nanotubes are difficult to remove, and it is considered difficult to improve the purity of the double-walled carbon nanotubes. Further, when the baking treatment is performed at the combustion peak temperature + 50 ° C. or higher, even the double-walled carbon nanotube disappears. Therefore, it is preferable to fire near the combustion peak temperature of the carbon nanotube aggregate. More preferably, it is the range of the combustion peak temperature ± 30 ° C. Specifically, the temperature for the baking treatment is preferably selected in the range of 300 to 900 ° C., more preferably 400 to 600 ° C. When the oxygen concentration is higher than the atmosphere, a lower temperature range is selected, and when the oxygen concentration is lower than the atmosphere, a higher temperature range is selected.
　カーボンナノチューブ集合体の燃焼ピーク温度は、示差熱分析装置により熱分析することで測定が可能である。約１ｍｇの試料を示差熱分析装置（例えば島津製作所製　示差熱・熱重量分析装置ＤＴＧ－６０Ａ）に設置し、空気中、１０℃／分の昇温速度にて室温から９００℃まで昇温する。その時、試料の燃焼時の発熱ピーク温度を求めることが可能である。 The combustion peak temperature of the carbon nanotube aggregate can be measured by thermal analysis using a differential thermal analyzer. About 1 mg of sample is placed in a differential thermal analyzer (eg, differential thermal / thermogravimetric analyzer DTG-60A manufactured by Shimadzu Corporation) and heated from room temperature to 900 ° C. at a heating rate of 10 ° C./min in air. . At that time, it is possible to determine the exothermic peak temperature during combustion of the sample.
　焼成処理時間は本発明のカーボンナノチューブが得られる限り特に限定されない。焼成温度が低いときは焼成処理時間を長く、焼成温度が高いときは焼成時間を短くするなどして、反応条件を調整することができる。焼成処理時間は、５分から２４時間が好ましく、より好ましくは１０分から１２時間、さらに好ましくは３０分から５時間である。焼成は大気下で行うことが好ましいが、酸素濃度を調節した酸素／不活性ガス下で行っても良い。このときの酸素濃度は特に限定されない。酸素０．１％～１００％の範囲で適宜設定して良い。また不活性ガスはヘリウム、窒素、アルゴン等が用いられる。 The firing time is not particularly limited as long as the carbon nanotube of the present invention is obtained. The reaction conditions can be adjusted by, for example, lengthening the firing time when the firing temperature is low and shortening the firing time when the firing temperature is high. The firing time is preferably 5 minutes to 24 hours, more preferably 10 minutes to 12 hours, and even more preferably 30 minutes to 5 hours. Firing is preferably performed in the air, but may be performed in an oxygen / inert gas with a controlled oxygen concentration. The oxygen concentration at this time is not particularly limited. Oxygen may be appropriately set in the range of 0.1% to 100%. As the inert gas, helium, nitrogen, argon or the like is used.
　また、気相酸化は、酸素または酸素を含む混合気体を間欠的にカーボンナノチューブに接触させて焼成処理を行なう方法によっても行なうことができる。酸素または酸素を含む混合気体を間欠的に接触させて焼成処理する場合は、比較的高温で処理が可能である。これは間欠的に酸素または酸素を含む混合気体を流すために、酸化が起きても、酸素を消費した時点ですぐに反応が停止するからである。大気と同等濃度の酸素下で焼成処理を行う場合は、温度範囲は、４００～１２００℃程度が好ましく、４５０～９５０℃程度がより好ましい。前述のようにカーボンナノチューブの製造時には、温度が５００～１２００℃程度になる。したがって、カーボンナノチューブの製造後、すぐに焼成処理をする場合は、このような間欠的焼成処理を行うことが好ましい。 Further, the gas phase oxidation can also be performed by a method in which oxygen or a mixed gas containing oxygen is intermittently brought into contact with the carbon nanotubes to perform a firing treatment. When firing is performed by intermittently contacting oxygen or a mixed gas containing oxygen, the treatment can be performed at a relatively high temperature. This is because, since oxygen or a mixed gas containing oxygen is intermittently flowed, even if oxidation occurs, the reaction stops immediately when oxygen is consumed. In the case where the baking treatment is performed under oxygen at the same concentration as the atmosphere, the temperature range is preferably about 400 to 1200 ° C., more preferably about 450 to 950 ° C. As described above, the temperature is about 500 to 1200 ° C. during the production of carbon nanotubes. Therefore, when the firing process is performed immediately after the production of the carbon nanotube, it is preferable to perform such an intermittent firing process.
　上記の様な気相酸化は、気相酸化後のカーボンナノチューブ集合体の測定波長５３２ｎｍにおけるラマンＧ／Ｄ比が３０以上になるまで行うことが好ましい。通常のカーボンナノチューブ集合体の製造方法では、このように気相酸化によりラマンＧ／Ｄ比を３０以上まで高めることは困難であったが、上述の製造方法により生成するカーボンナノチューブ集合体は高品質であるために、気相酸化しても欠陥が生成することなく、アモルファスカーボン等の副生物を除去することが可能であるため、このようにラマンＧ／Ｄ比を３０以上に向上させることが可能である。 The gas phase oxidation as described above is preferably performed until the Raman G / D ratio of the aggregate of carbon nanotubes after the gas phase oxidation at a measurement wavelength of 532 nm reaches 30 or more. In the usual method for producing an aggregate of carbon nanotubes, it was difficult to increase the Raman G / D ratio to 30 or more by gas phase oxidation as described above. However, the aggregate of carbon nanotubes produced by the above production method is of high quality. Therefore, it is possible to remove by-products such as amorphous carbon without generating defects even when vapor-phase oxidation is performed. Thus, the Raman G / D ratio can be improved to 30 or more. Is possible.
　本発明のカーボンナノチューブ集合体を用いることにより、非常に導電性の高いカーボンナノチューブ成形体を製造することができる。好適には非常に導電性の高い強度的にも優れたカーボンナノチューブ成形体を製造することができる。 By using the carbon nanotube aggregate of the present invention, it is possible to produce a carbon nanotube molded body with extremely high conductivity. Preferably, a carbon nanotube molded body having very high conductivity and excellent strength can be produced.
　カーボンナノチューブ成形体とは、カーボンナノチューブ集合体が、成形あるいは加工により、賦形された状態にあるものをいう。また、成形あるいは加工とは、カーボンナノチューブ集合体の形状が変わる操作や工程を経過するすべての操作を示す。カーボンナノチューブ成形体の例としては、カーボンナノチューブ集合体からなる糸、チップ、ペレット、シート、ブロック等があげられる。これらを組み合わせたもの、またはさらに成形あるいは加工を施した結果物もカーボンナノチューブ成形体とする。 The carbon nanotube molded body refers to a carbon nanotube aggregate that has been shaped by molding or processing. Molding or processing refers to all operations that pass through operations and processes that change the shape of the carbon nanotube aggregate. Examples of the carbon nanotube molded body include yarns, chips, pellets, sheets, blocks, and the like made of a carbon nanotube aggregate. A combination of these, or a result obtained by further molding or processing is also a carbon nanotube molded body.
　カーボンナノチューブ集合体の成形方法は、特に限定されないが、例えば、溶媒中にカーボンナノチューブ集合体を分散し、分散液をろ過、乾燥することにより、カーボンナノチューブ集合体のシートを作製することができる。またカーボンナノチューブ集合体を分散した分散液を細い口金から糸状に吐出して、凝固浴に含浸することにより、カーボンナノチューブ集合体の糸として成形することも可能である。 The method for forming the carbon nanotube aggregate is not particularly limited. For example, the carbon nanotube aggregate sheet can be produced by dispersing the carbon nanotube aggregate in a solvent, filtering the dispersion, and drying. It is also possible to form a carbon nanotube aggregate thread by discharging a dispersion liquid in which the carbon nanotube aggregate is dispersed into a thread from a thin die and impregnating the coagulation bath.
　本発明のカーボンナノチューブ集合体は、カーボンナノチューブ以外の物質に混合または分散させることによって、非常に導電性の高い、強度に優れた、または、熱伝導性に優れた組成物とすることができる。ここでいうカーボンナノチューブ以外の物質とは、例えば樹脂、金属、ガラス、液状の分散媒などであり、接着剤やセメント、石膏、セラミックスのようなものでもよい。カーボンナノチューブ集合体を含む組成物とは、これらの物質にカーボンナノチューブ集合体が混合または分散されている状態の物質全てをいう。ここでいう分散とは、カーボンナノチューブ集合体中のカーボンナノチューブが一本ずつほぐれている状態でも、バンドルを組んだ状態でも、１本から様々な太さのバンドルが混ざっている状態でも良く、カーボンナノチューブが上記物質中に均一に散らばっていればよい。また、ここでいう混合されている状態とは、カーボンナノチューブ集合体が上記物質に不均一に散らばっている状態や、単に、固体状のカーボンナノチューブ集合体と固体状態の上記物質を混ぜ合わせただけの状態も含まれる。 The aggregate of carbon nanotubes of the present invention can be made into a composition having very high conductivity, excellent strength, or excellent thermal conductivity by mixing or dispersing in a substance other than carbon nanotubes. Substances other than carbon nanotubes here are, for example, resin, metal, glass, liquid dispersion medium, and the like, and may be an adhesive, cement, gypsum, ceramics, or the like. The composition containing an aggregate of carbon nanotubes means all substances in a state where the aggregate of carbon nanotubes is mixed or dispersed in these substances. The term “dispersion” as used herein refers to a state in which the carbon nanotubes in the carbon nanotube aggregate are loosened one by one, in a bundled state, or in a state where bundles of various thicknesses are mixed from one, It is sufficient that the nanotubes are evenly dispersed in the substance. In addition, the mixed state here refers to a state in which the carbon nanotube aggregates are scattered unevenly in the substance, or simply a mixture of the solid carbon nanotube aggregate and the solid substance. Is also included.
　上記組成物における各成分の好ましい含有量は、以下のとおりである。すなわち、カーボンナノチューブ集合体を含有する組成物は、カーボンナノチューブを０．０１重量％以上含有していることが好ましく、０．１重量％以上含有していることがより好ましい。含有量の上限としては、２０重量％以下であることが好ましい。カーボンナノチューブの含有量が２０重量％を超えると、組成物の取扱いが困難になる場合がある。カーボンナノチューブの含有量は、より好ましくは５重量％以下、さらに好ましくは２重量％以下である。 The preferred content of each component in the composition is as follows. That is, the composition containing the aggregate of carbon nanotubes preferably contains 0.01% by weight or more of carbon nanotubes, and more preferably contains 0.1% by weight or more. The upper limit of the content is preferably 20% by weight or less. When the content of the carbon nanotubes exceeds 20% by weight, it may be difficult to handle the composition. The content of carbon nanotubes is more preferably 5% by weight or less, still more preferably 2% by weight or less.
　本発明のカーボンナノチューブ集合体を含む組成物を用いることにより、非常に導電性の高い成形体を製造することができる。ここで、カーボンナノチューブ集合体を含む組成物からなる成形体とは、上記組成物の中でも、固形状のものを圧縮、裁断、粉砕、伸張、穿穴などの操作によって成形あるいは加工されたものや、溶融後特定の形で再び固形状にしたもののことである。 By using the composition containing the aggregate of carbon nanotubes of the present invention, it is possible to produce a molded article having very high conductivity. Here, a molded article made of a composition containing an aggregate of carbon nanotubes is a molded article that has been molded or processed by operations such as compression, cutting, crushing, stretching, and punching among solid compositions. It is the one that has been solidified again in a specific form after melting.
　上記カーボンナノチューブ以外の物質のうち、樹脂としては、本発明のカーボンナノチューブ集合体を混合または分散できるものであれば特に制限はなく、天然樹脂であっても合成樹脂であっても良い。また、合成樹脂としては熱硬化性樹脂も熱可塑性樹脂も好適に使用できる。カーボンナノチューブ以外の物質が熱可塑性樹脂である組成物は、得られた成形体の衝撃強度に優れ、かつ成形効率の高いプレス成形や射出成形が可能であるため好ましい。 Of the substances other than the carbon nanotubes, the resin is not particularly limited as long as it can mix or disperse the carbon nanotube aggregate of the present invention, and may be a natural resin or a synthetic resin. Further, as the synthetic resin, a thermosetting resin or a thermoplastic resin can be suitably used. A composition in which a substance other than carbon nanotubes is a thermoplastic resin is preferable because the obtained molded article has excellent impact strength and can be subjected to press molding and injection molding with high molding efficiency.
　熱硬化性樹脂としては、特に限定されないが、例えば不飽和ポリエステル樹脂、ビニルエステル樹脂、エポキシ樹脂、シアネートエステル樹脂、ベンゾオキサジン樹脂、フェノール（レゾール型）樹脂、ユリア・メラミン樹脂、熱硬化性ポリイミドや、これらの共重合体、これらの変性体、または、これらの２種類以上をブレンドした樹脂などを使用することができる。また、さらに耐衝撃性向上のために、上記熱硬化性樹脂にエラストマー、合成ゴム、天然ゴムもしくはシリコーン等の柔軟成分を添加した樹脂であってもよい。 The thermosetting resin is not particularly limited. For example, unsaturated polyester resin, vinyl ester resin, epoxy resin, cyanate ester resin, benzoxazine resin, phenol (resole type) resin, urea melamine resin, thermosetting polyimide, These copolymers, modified products thereof, or resins obtained by blending two or more of them can be used. Further, in order to further improve impact resistance, a resin obtained by adding a flexible component such as elastomer, synthetic rubber, natural rubber or silicone to the thermosetting resin may be used.
　熱可塑性樹脂としては、特に限定されないが、例えば、液晶ポリエステル、非液晶ポリエステル等のポリエステル樹脂や、ポリエチレン、ポリプロピレン、ポリブチレン等のポリオレフィンや、スチレン系樹脂の他、ポリオキシメチレン、ポリアミド、ポリカーボネート樹脂、ポリメチレンメタクリレート、ポリ塩化ビニル、ポリフェニレンスルフィド樹脂、ポリフェニレンエーテル、ポリアミド樹脂、熱可塑性ポリイミド、ポリアミドイミド、ポリエーテルイミド、ポリスルホン、ポリエーテルスルホン、ポリケトン、ポリエーテルケトン、ポリエーテルエーテルケトン、ポリエーテルケトンケトン、ポリアリレート、ポリエーテルニトリル、フェノール（ノボラック型など）樹脂、フェノキシ樹脂、ポリテトラフルオロエチレンなどのフッ素系樹脂、さらにポリスチレン系、ポリオレフィン系、ポリウレタン系、ポリエステル系、ポリアミド系、ポリブタジエン系、ポリイソプレン系、フッ素系等の熱可塑エラストマー、これらの共重合体、変性体、およびこれらの樹脂を２種類以上ブレンドした樹脂などが挙げられる。また、さらに耐衝撃性向上のために、上記熱可塑性樹脂にその他のエラストマー、合成ゴム、天然ゴムもしくはシリコーン等の柔軟成分を添加した樹脂であってもよい。 The thermoplastic resin is not particularly limited. For example, in addition to polyester resins such as liquid crystal polyester and non-liquid crystal polyester, polyolefins such as polyethylene, polypropylene, and polybutylene, styrene resins, polyoxymethylene, polyamide, polycarbonate resin, Polymethylene methacrylate, polyvinyl chloride, polyphenylene sulfide resin, polyphenylene ether, polyamide resin, thermoplastic polyimide, polyamideimide, polyetherimide, polysulfone, polyethersulfone, polyketone, polyetherketone, polyetheretherketone, polyetherketoneketone , Polyarylate, polyether nitrile, phenol (novolak type, etc.) resin, phenoxy resin, polytetrafluoroethylene, etc. Fluorine-based resins, polystyrene-based, polyolefin-based, polyurethane-based, polyester-based, polyamide-based, polybutadiene-based, polyisoprene-based, fluorine-based thermoplastic elastomers, their copolymers, modified products, and these resins Examples include resins blended in two or more types. Further, in order to further improve impact resistance, a resin obtained by adding a flexible component such as another elastomer, synthetic rubber, natural rubber, or silicone to the thermoplastic resin may be used.
　樹脂としては、合成ゴム、天然ゴムもしくはシリコーン等のエラストマーだけでもよい。その他、ポリビニルアルコールに代表されるポリアルコール系樹脂、ポリ酢酸ビニルに代表されるポリカルボン酸系樹脂、ポリアクリル酸エステルなどのアクリル樹脂や、ポリアクリロニトリルも挙げられる。また、アクリル系、シリコーン系、酢酸ビニル樹脂、ビニルエーテル樹脂等のビニル系などの接着剤、粘着剤も挙げることができる。 Resin may be only synthetic rubber, natural rubber, or elastomer such as silicone. Other examples include polyalcohol resins typified by polyvinyl alcohol, polycarboxylic acid resins typified by polyvinyl acetate, acrylic resins such as polyacrylic acid esters, and polyacrylonitrile. In addition, vinyl-based adhesives such as acrylic, silicone-based, vinyl acetate resin, vinyl ether resin, and pressure-sensitive adhesives can also be mentioned.
　カーボンナノチューブ以外の物質のうち、金属としては、アルミニウム、銅、銀、金、鉄、ニッケル、亜鉛、鉛、スズ、コバルト、クロム、チタン、タングステンなどを単独または複合して使用できる。また、ガラスとしては、ソーダ石灰ガラス、鉛ガラス、ほう酸ガラスなどが挙げられる。 Among the substances other than carbon nanotubes, as the metal, aluminum, copper, silver, gold, iron, nickel, zinc, lead, tin, cobalt, chromium, titanium, tungsten, etc. can be used alone or in combination. Examples of the glass include soda lime glass, lead glass, and borate glass.
　また、本発明においては、カーボンナノチューブ集合体は、液状の分散媒に分散させた組成物（以後、カーボンナノチューブ分散液とも呼ぶ）とすることができる。 In the present invention, the aggregate of carbon nanotubes can be a composition dispersed in a liquid dispersion medium (hereinafter also referred to as a carbon nanotube dispersion).
　カーボンナノチューブ分散液において、界面活性剤、導電性高分子もしくは非導電性高分子等の添加剤をさらに含有させることも好ましい。なぜなら、上記界面活性剤やある種の高分子材料は、カーボンナノチューブの分散能や分散安定化能等を向上させるのに役立つからである。 In the carbon nanotube dispersion liquid, it is also preferable to further contain an additive such as a surfactant, a conductive polymer or a non-conductive polymer. This is because the above-described surfactant and certain polymer materials are useful for improving the dispersibility and dispersion stabilization capability of carbon nanotubes.
　界面活性剤等の添加剤の含有量は、特に限定されるものではないが、好ましくは、０．１～５０重量％、より好ましくは、０．２～３０重量％である。上記添加剤とカーボンナノチューブの混合比（添加剤／カーボンナノチューブ）は、特に限定されないが、重量比で好ましくは０．１～２０、より好ましくは０．３～１０である。本発明のカーボンナノチューブ分散液は、カーボンナノチューブ、界面活性剤等の添加剤および分散媒以外の物質が含まれていてもかまわない。 The content of an additive such as a surfactant is not particularly limited, but is preferably 0.1 to 50% by weight, more preferably 0.2 to 30% by weight. The mixing ratio of the additive and carbon nanotube (additive / carbon nanotube) is not particularly limited, but is preferably 0.1 to 20, more preferably 0.3 to 10 by weight. The carbon nanotube dispersion of the present invention may contain additives other than carbon nanotubes, surfactants, and substances other than the dispersion medium.
　界面活性剤は、イオン性界面活性剤と非イオン性界面活性剤に分けられるが、本発明ではいずれの界面活性剤を用いることも可能である。イオン性界面活性剤としては、例えば以下のような界面活性剤があげられる。かかる界面活性剤は単独でもしくは２種以上を混合して用いることができる。 Surfactants are classified into ionic surfactants and nonionic surfactants, but any surfactant can be used in the present invention. Examples of the ionic surfactant include the following surfactants. Such surfactants can be used alone or in admixture of two or more.
　イオン性界面活性剤は、陽イオン性界面活性剤、両イオン性界面活性剤および陰イオン性界面活性剤にわけられる。陽イオン性界面活性剤としては、アルキルアミン塩、第四級アンモニウム塩などがあげられる。両イオン性界面活性剤としては、アルキルベタイン系界面活性剤、アミンオキサイド系界面活性剤がある。陰イオン性界面活性剤としては、ドデシルベンゼンスルホン酸等のアルキルベンゼンスルホン酸塩、ドデシルフェニルエーテルスルホン酸塩等の芳香族スルホン酸系界面活性剤、モノソープ系アニオン性界面活性剤、エーテルサルフェート系界面活性剤、フォスフェート系界面活性剤、カルボン酸系界面活性剤であり、中でも、分散能、分散安定能、高濃度化に優れることから、芳香環を含むもの、すなわち芳香族系イオン性界面活性剤が好ましく、特にアルキルベンゼンスルホン酸塩、ドデシルフェニルエーテルスルホン酸塩等の芳香族系イオン性界面活性剤が好ましい。 The ionic surfactant is classified into a cationic surfactant, an amphoteric surfactant and an anionic surfactant. Examples of the cationic surfactant include alkylamine salts and quaternary ammonium salts. Examples of amphoteric surfactants include alkylbetaine surfactants and amine oxide surfactants. Examples of anionic surfactants include alkylbenzene sulfonates such as dodecylbenzene sulfonic acid, aromatic sulfonic acid surfactants such as dodecyl phenyl ether sulfonate, monosoap anionic surfactants, ether sulfate-based interfaces Activators, phosphate surfactants, carboxylic acid surfactants. Among them, those that contain an aromatic ring because of their excellent dispersibility, dispersion stability, and high concentration, that is, aromatic ionic surfactants An aromatic ionic surfactant such as alkylbenzene sulfonate and dodecyl phenyl ether sulfonate is particularly preferable.
　非イオン性界面活性剤としては、例えば以下のような界面活性剤をあげられる。かかる界面活性剤は単独でもしくは２種以上を混合して用いることができる。 Examples of nonionic surfactants include the following surfactants. Such surfactants can be used alone or in admixture of two or more.
　非イオン性界面活性剤の例としては、ソルビタン脂肪酸エステル、ポリオキシエチレンソルビタン脂肪酸エステルなどの糖エステル系界面活性剤、ポリオキシエチレン樹脂酸エステル、ポリオキシエチレン脂肪酸ジエチルなどの脂肪酸エステル系界面活性剤、ポリオキシエチレンアルキルエーテル、ポリオキシエチレンアルキルフェニルエーテル、ポリオキシエチレン・ポリプロピレングリコールなどのエーテル系界面活性剤、ポリオキシアルキレンオクチルフェニルエーテル、ポリオキシアルキレンノニルフェニルエーテル、ポリオキシアルキルジブチルフェニルエーテル、ポリオキシアルキルスチリルフェニルエーテル、ポリオキシアルキルベンジルフェニルエーテル、ポリオキシアルキルビスフェニルエーテル、ポリオキシアルキルクミルフェニルエーテル等の芳香族系非イオン性界面活性剤があげられる。中でも、分散能、分散安定能、高濃度化に優れることから、芳香族系非イオン性界面活性剤が好ましく、中でもポリオキシエチレンフェニルエーテルが好ましい。 Examples of nonionic surfactants include sugar ester surfactants such as sorbitan fatty acid esters and polyoxyethylene sorbitan fatty acid esters, fatty acid ester surfactants such as polyoxyethylene resin acid esters and polyoxyethylene fatty acid diethyl , Polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, ether surfactants such as polyoxyethylene / polypropylene glycol, polyoxyalkylene octyl phenyl ether, polyoxyalkylene nonyl phenyl ether, polyoxyalkyl dibutyl phenyl ether, poly Oxyalkyl styryl phenyl ether, polyoxyalkyl benzyl phenyl ether, polyoxyalkyl bisphenyl ether, polyoxyalkyl Aromatic anionic surfactants such as mill phenyl ether. Of these, aromatic nonionic surfactants are preferred because of their excellent dispersibility, dispersion stability, and high concentration, and polyoxyethylene phenyl ether is particularly preferred.
　導電性高分子もしくは非導電性高分子の高分子材料としては、例えば、ポリビニルアルコール、ポリビニルピロリドン、ポリスチレンスルホン酸アンモニウム塩、ポリスチレンスルホン酸ナトリウム塩等の水溶性ポリマー、カルボキシメチルセルロースナトリウム塩（Ｎa－ＣＭＣ）、メチルセルロース、ヒドロキシエチルセルロース、アミロース、シクロアミロース、キトサン等の糖類ポリマー等がある。またポリチオフェン、ポリエチレンジオキシチオフェン、ポリイソチアナフテン、ポリアニリン、ポリピロール、ポリアセチレン等の導電性ポリマーおよびそれらの誘導体も使用できる。 Examples of the polymer material of the conductive polymer or non-conductive polymer include water-soluble polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, polystyrene sulfonate ammonium salt, polystyrene sulfonate sodium salt, carboxymethyl cellulose sodium salt (Na-CMC). ), Sugar polymers such as methyl cellulose, hydroxyethyl cellulose, amylose, cycloamylose, and chitosan. In addition, conductive polymers such as polythiophene, polyethylenedioxythiophene, polyisothianaphthene, polyaniline, polypyrrole, polyacetylene, and derivatives thereof can also be used.
　カーボンナノチューブ分散液の製造方法には特に制限はなく、例えばカーボンナノチューブ集合体と添加剤、分散媒を塗装製造に慣用の混合分散機（例えばボールミル、ビーズミル、サンドミル、ロールミル、ホモジナイザー、アトライター、デゾルバー、ペイントシェーカー等）を用いて混合し、分散液を製造することができる。 There are no particular restrictions on the method for producing the carbon nanotube dispersion, for example, a carbon nanotube aggregate and additives, and a dispersion medium commonly used for coating production, such as a ball mill, bead mill, sand mill, roll mill, homogenizer, attritor, resolver. , A paint shaker or the like) to produce a dispersion.
　特に優れた導電性を得る場合や、透明電極の導電層に利用する場合は、上記カーボンナノチューブ分散液は、塗布前に遠心分離、フィルター濾過等によって、サイズ分画することが好ましい。例えば、分散液を遠心分離することによって、未分散のカーボンナノチューブや、過剰量の添加剤、カーボンナノチューブ合成時に混入する可能性のある触媒などは沈殿するので、遠心上清を回収すれば、分散液中に分散しているカーボンナノチューブを、液の形で採取することができる。未分散のカーボンナノチューブ、不純物などは沈殿物として除去することができ、それによって、カーボンナノチューブの再凝集を防止でき、分散液の安定性を向上することができる。さらに、強力な遠心力においては、カーボンナノチューブの太さや長さによって分離することができ、光透過率を向上させることができる。 When obtaining particularly excellent conductivity or when used for a conductive layer of a transparent electrode, the carbon nanotube dispersion liquid is preferably subjected to size fractionation by centrifugation, filter filtration or the like before coating. For example, by centrifuging the dispersion, undispersed carbon nanotubes, excessive amounts of additives, catalysts that may be mixed during carbon nanotube synthesis, etc. are precipitated. The carbon nanotubes dispersed in the liquid can be collected in the form of a liquid. Undispersed carbon nanotubes, impurities, and the like can be removed as precipitates, whereby reaggregation of the carbon nanotubes can be prevented and the stability of the dispersion can be improved. Furthermore, in strong centrifugal force, it can isolate | separate with the thickness and length of a carbon nanotube, and can improve the light transmittance.
　遠心分離する際の遠心力は、１００Ｇ以上の遠心力であればよく、好ましくは、１０００Ｇ以上、より好ましくは１０，０００Ｇ以上である。上限としては特に制限はないが、汎用超遠心機の性能より２００，０００Ｇ以下であることが好ましい。 The centrifugal force at the time of centrifugation may be 100 G or more, preferably 1000 G or more, and more preferably 10,000 G or more. Although there is no restriction | limiting in particular as an upper limit, It is preferable that it is 200,000G or less from the performance of a general purpose ultracentrifuge.
　また、フィルター濾過に用いるフィルターは、０．０５μｍから０．２μｍの間で適宜選択することができる。それにより、未分散のカーボンナノチューブや、カーボンナノチューブ合成時に混入する可能性のある不純物等のうち比較的サイズの大きいものを除去することができる。 Further, the filter used for filter filtration can be appropriately selected between 0.05 μm and 0.2 μm. Thereby, it is possible to remove undispersed carbon nanotubes and impurities having a relatively large size among impurities that may be mixed during synthesis of the carbon nanotubes.
　このようにサイズ分画する場合においては、この分画される量を見越して、サイズ分画後の組成が上記範囲となるように調製する。このようなサイズ分画の結果、カーボンナノチューブの長さや、層数、バンドル構造の有無などでカーボンナノチューブを分離することができる。 In the case of size fractionation in this way, the composition after size fractionation is prepared in the above range in anticipation of the fractionated amount. As a result of such size fractionation, the carbon nanotubes can be separated according to the length of the carbon nanotubes, the number of layers, the presence or absence of a bundle structure, and the like.
　液状の分散媒としては、水系溶媒でも良いし非水系溶媒でも良い。非水系溶媒としては、炭化水素類（トルエン、キシレン等）、塩素含有炭化水素類（メチレンクロリド、クロロホルム、クロロベンゼン等）、エーテル類（ジオキサン、テトラヒドロフラン、メチルセロソルブ等）、エーテルアルコール（エトキシエタノール、メトキシエトキシエタノール等）、エステル類（酢酸メチル、酢酸エチル等）、ケトン類（シクロヘキサノン、メチルエチルケトン等）、アルコール類（エタノール、イソプロパノール、フェノール等）、低級カルボン酸（酢酸等）、アミン類（トリエチルアミン、トリメタノールアミン等）、窒素含有極性溶媒（Ｎ，Ｎ－ジメチルホルムアミド、ニトロメタン、Ｎ－メチルピロリドン等）、硫黄化合物類（ジメチルスルホキシド等）などを用いることができる。 The liquid dispersion medium may be an aqueous solvent or a non-aqueous solvent. Non-aqueous solvents include hydrocarbons (toluene, xylene, etc.), chlorine-containing hydrocarbons (methylene chloride, chloroform, chlorobenzene, etc.), ethers (dioxane, tetrahydrofuran, methyl cellosolve, etc.), ether alcohols (ethoxyethanol, methoxy) Ethoxyethanol, etc.), esters (methyl acetate, ethyl acetate, etc.), ketones (cyclohexanone, methyl ethyl ketone, etc.), alcohols (ethanol, isopropanol, phenol, etc.), lower carboxylic acids (acetic acid, etc.), amines (triethylamine, triethylamine, etc.) Methanolamine, etc.), nitrogen-containing polar solvents (N, N-dimethylformamide, nitromethane, N-methylpyrrolidone, etc.), sulfur compounds (dimethyl sulfoxide, etc.) and the like can be used.
　これらのなかでも分散媒としては、水、アルコール、トルエン、アセトン、エーテルおよびそれらを組み合わせたものから選ばれる溶媒が好ましい。水系溶媒が必要である場合、および後述するようにバインダーを用いる場合であって、そのバインダーが無機ポリマー系バインダーの場合には、水、アルコール類、アミン類などの極性溶媒が好ましく使用される。また、後述するようにバインダーとして常温で液状のものを用いる場合には、それ自体を分散媒として用いることもできる。 Among these, the dispersion medium is preferably a solvent selected from water, alcohol, toluene, acetone, ether, and combinations thereof. When an aqueous solvent is required and when a binder is used as will be described later, and the binder is an inorganic polymer binder, polar solvents such as water, alcohols and amines are preferably used. Moreover, when using a liquid thing at normal temperature as a binder so that it may mention later, itself can also be used as a dispersion medium.
　本発明の導電性複合体は、上記のカーボンナノチューブ集合体を含む導電層が基材上に形成されたものである。 The conductive composite of the present invention is obtained by forming a conductive layer containing the above carbon nanotube aggregate on a substrate.
　本発明において、導電層を形成する方法としては、前記カーボンナノチューブ分散液を使用することが可能である。カーボンナノチューブ分散液を公知の塗布方法、例えば吹き付け塗装、浸漬コーティング、スピンコーティング、ナイフコーティング、キスコーティング、グラビアコーティング、スクリーン印刷、インクジェット印刷、パット印刷、他の種類の印刷、またはロールコーティングなどを用いて、基材上に塗布する方法が利用できる。最も好ましい塗布方法は、ロールコーティングである。また塗布は、何回行ってもよく、異なる２種類の塗布方法を組み合わせても良い。分散液の分散媒が揮発性の場合は風乾、加熱、減圧などの方法により不要な分散媒を除去することができる。それによりカーボンナノチューブは、３次元編目構造を形成し、基材に固定化される。その後、液中の成分である界面活性剤、導電性高分子もしくは非導電性高分子等の添加剤を適当な溶媒を用いて除去するのも好ましい。この操作により、電荷の分散が容易になり、導電層の導電性が向上する。添加剤を除去するための溶媒としては、添加剤を溶解するものであれば特に制限はなく、水性溶媒でも非水性溶媒でもよい。具体的には水性溶媒であれば、水やアルコール類が挙げられ、非水性溶媒であれば、クロロホルム、アセトニトリルなどがあげられる。 In the present invention, the carbon nanotube dispersion can be used as a method for forming the conductive layer. The carbon nanotube dispersion is applied by a known application method such as spray coating, dip coating, spin coating, knife coating, kiss coating, gravure coating, screen printing, inkjet printing, pad printing, other types of printing, or roll coating. Thus, a method of coating on a substrate can be used. The most preferred application method is roll coating. The application may be performed any number of times, and two different application methods may be combined. When the dispersion medium of the dispersion liquid is volatile, unnecessary dispersion medium can be removed by methods such as air drying, heating, and decompression. Thereby, the carbon nanotube forms a three-dimensional stitch structure and is fixed to the base material. Then, it is also preferable to remove additives, such as surfactant, conductive polymer, or nonconductive polymer, which are components in the liquid, using a suitable solvent. This operation facilitates the dispersion of charges and improves the conductivity of the conductive layer. The solvent for removing the additive is not particularly limited as long as it dissolves the additive, and may be an aqueous solvent or a non-aqueous solvent. Specifically, if it is an aqueous solvent, water and alcohols can be mentioned, and if it is a non-aqueous solvent, chloroform, acetonitrile and the like can be mentioned.
　導電層の導電性を向上させたい場合は、カーボンナノチューブ組成物中のカーボンナノチューブ量を増やすことも可能である。また、少ないカーボンナノチューブ量で、より導電性を向上させるためには、カーボンナノチューブはカーボンナノチューブ組成物中に均一に分散するほど好ましく、カーボンナノチューブのバンドルは細いほど好ましく、カーボンナノチューブはバンドルがほぐれた１本だけの状態で分散していることがより好ましい。バンドルの太さの調整については、前記分散方法の分散時間や添加剤として加えた界面活性剤、導電性高分子もしくは非導電性高分子等の種類を変えることで調整が可能である。 When it is desired to improve the conductivity of the conductive layer, the amount of carbon nanotubes in the carbon nanotube composition can be increased. Further, in order to improve the conductivity with a small amount of carbon nanotubes, it is preferable that the carbon nanotubes are uniformly dispersed in the carbon nanotube composition, the bundle of carbon nanotubes is preferable, and the bundle of carbon nanotubes is loosened. More preferably, it is dispersed in a single state. The thickness of the bundle can be adjusted by changing the dispersion time of the dispersion method or the type of surfactant, conductive polymer or non-conductive polymer added as an additive.
　また、カーボンナノチューブ分散液は、所望のカーボンナノチューブ含有量よりも高濃度の分散液を作製し、溶媒で薄めて所望の濃度として使用することも可能である。導電性がさほど必要で無い用途は、カーボンナノチューブの濃度を薄めて使うこともあるし、最初から濃度が薄い状態で作製しても良い。 Also, the carbon nanotube dispersion can be used as a desired concentration by preparing a dispersion having a concentration higher than the desired carbon nanotube content and diluting with a solvent. In applications where conductivity is not so necessary, the concentration of carbon nanotubes may be reduced, or the carbon nanotubes may be manufactured with a low concentration from the beginning.
　基材としては、特に限定されないが、基材が透明基材であると、透明導電性複合体が得られるので好ましい。透明基材としては、例えばＰＥＴフィルムのようなフィルムが特に好ましい。 Although it does not specifically limit as a base material, Since a transparent conductive composite body is obtained when a base material is a transparent base material, it is preferable. As the transparent substrate, a film such as a PET film is particularly preferable.
　ただし、基材としては、透明基材だけでなく、あらゆる基材、例えば着色基材および繊維なども使える。例えば、本発明のカーボンナノチューブ分散液を、クリーンルームなどの床材や壁材にコーティングすれば帯電防止床壁材として使用できるし、繊維に塗布すれば帯電防止衣服やマット、カーテンなどとして使用できる。 However, as the substrate, not only a transparent substrate but also any substrate such as a colored substrate and fiber can be used. For example, the carbon nanotube dispersion liquid of the present invention can be used as an antistatic floor wall material when coated on a floor material or wall material in a clean room or the like, and can be used as an antistatic garment, mat, curtain or the like when coated on a fiber.
　本発明においては上記のように基材上に導電層を形成した後、導電層を有機または無機透明被膜を形成しうるバインダー材料でオーバーコーティングすることも好ましい。オーバーコーティングすることにより、さらなる電荷の分散や、移動に効果的である。 In the present invention, after forming a conductive layer on a substrate as described above, it is also preferable to overcoat the conductive layer with a binder material capable of forming an organic or inorganic transparent film. By overcoating, it is effective for further charge dispersion and movement.
　また、導電性複合体は、カーボンナノチューブ分散液中に透明被膜を形成しうるバインダー材料を含有させ、基材に塗布後、必要により加熱して、塗膜の乾燥ないし硬化を行っても得ることができる。その際の加熱条件は、バインダー種に応じて適当に設定する。バインダーが光硬化性または放射線硬化性の場合には、加熱硬化ではなく、塗布後直ちに塗膜に光または放射線を照射することにより塗膜を硬化させる。放射線としては電子線、紫外線、Ｘ線、ガンマー線等のイオン化性放射線が使用でき、照射線量はバインダー種に応じて決定する。 In addition, the conductive composite can be obtained by containing a binder material capable of forming a transparent film in the carbon nanotube dispersion liquid, and applying to the base material, followed by heating as necessary to dry or cure the film. Can do. The heating conditions at that time are appropriately set according to the binder type. When the binder is photocurable or radiation curable, the coating film is cured by irradiating the coating film with light or radiation immediately after coating, not by heat curing. As the radiation, ionizing radiation such as electron beam, ultraviolet ray, X-ray and gamma ray can be used, and the irradiation dose is determined according to the binder type.
　上記バインダー材料としては、導電性塗料に使用されるものであれば特に制限はなく、各種の透明な有機ポリマーまたはその前駆体（以下「有機ポリマー系バインダー」と称する場合もある）または無機ポリマーまたはその前駆体（以下「無機ポリマー系バインダー」と称する場合もある）が使用できる。 The binder material is not particularly limited as long as it is used for conductive paints. Various transparent organic polymers or precursors thereof (hereinafter sometimes referred to as “organic polymer binders”) or inorganic polymers or A precursor thereof (hereinafter sometimes referred to as “inorganic polymer binder”) can be used.
　有機ポリマー系バインダーは熱可塑性、熱硬化性、光硬化性、あるいは放射線硬化性のいずれであってもよい。有機バインダーの例としては、ポリオレフィン系（ポリエチレン、ポリプロピレン等）、ポリアミド系（ナイロン６、ナイロン１１、ナイロン６６、ナイロン６，１０等）、ポリエステル系（ポリエチレンテレフタレート、ポリブチレンテレフタレート等）、シリコーン系ポリマー、ビニル系樹脂（ポリ塩化ビニル、ポリ塩化ビニリデン、ポリアクリロニトリル、ポリアクリレート、ポリスチレン誘導体、ポリ酢酸ビニル、ポリビニルアルコール等）、ポリケトン、ポリイミド、ポリカーボネート、ポリスルホン、ポリアセタール、フッ素樹脂、フェノール樹脂、尿素樹脂、メラニン樹脂、エポキシ樹脂、ポリウレタン、セルロース系ポリマー、蛋白質類（ゼラチン、カゼイン等）、キチン、ポリペプチド、多糖類、ポリヌクレオチドなど有機ポリマー、ならびにこれらのポリマーの前駆体（モノマー、オリゴマー）が挙げられる。これらは単に溶剤の蒸発により、あるいは熱硬化または光照射もしくは放射線照射による硬化により有機ポリマー系透明被膜を形成することができる。 The organic polymer binder may be any one of thermoplastic, thermosetting, photocurable, and radiation curable. Examples of organic binders include polyolefins (polyethylene, polypropylene, etc.), polyamides (nylon 6, nylon 11, nylon 66, nylon 6, 10, etc.), polyesters (polyethylene terephthalate, polybutylene terephthalate, etc.), silicone polymers , Vinyl resins (polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polyacrylate, polystyrene derivatives, polyvinyl acetate, polyvinyl alcohol, etc.), polyketone, polyimide, polycarbonate, polysulfone, polyacetal, fluororesin, phenol resin, urea resin, Melanin resin, epoxy resin, polyurethane, cellulosic polymer, proteins (gelatin, casein, etc.), chitin, polypeptide, polysaccharide, polynucleotide, etc. Polymers, and precursors of these polymers (monomer, oligomer) can be mentioned. These can form an organic polymer transparent film simply by evaporation of a solvent, or by heat curing or curing by light irradiation or radiation irradiation.
　無機ポリマー系バインダーの例としては、シリカ、酸化錫、酸化アルミニウム、酸化ジルコニウム等の金属酸化物のゾル、あるいは無機ポリマーの前駆体となる加水分解性または熱分解性の有機リン化合物および有機ボロン化合物、ならびに有機シラン化合物、有機チタン化合物、有機ジルコニウム化合物、有機鉛化合物、有機アルカリ土類金属化合物などの有機金属化合物がある。加水分解性または熱分解性の有機金属化合物の具体的例は、アルコキシドまたはその部分加水分解物、酢酸塩などの低級カルボン酸塩、アセチルアセトンなどの金属錯体である。 Examples of inorganic polymer binders include sols of metal oxides such as silica, tin oxide, aluminum oxide, and zirconium oxide, or hydrolyzable or thermally decomposable organophosphorus compounds and organoboron compounds that are precursors of inorganic polymers. And organic metal compounds such as organic silane compounds, organic titanium compounds, organic zirconium compounds, organic lead compounds, and organic alkaline earth metal compounds. Specific examples of hydrolyzable or thermally decomposable organometallic compounds are alkoxides or partial hydrolysates thereof, lower carboxylates such as acetate, and metal complexes such as acetylacetone.
　これらの１種もしくは２種以上の無機ポリマー系バインダーを焼成すると、酸化物または複合酸化物からなるガラス質の無機ポリマー系透明被膜を形成することができる。無機ポリマー系透明被膜は、高硬度で耐擦過性に優れ、透明性も高い。 When one or more of these inorganic polymer binders are baked, a glassy inorganic polymer transparent film made of an oxide or a composite oxide can be formed. The inorganic polymer transparent film has high hardness, excellent scratch resistance, and high transparency.
　光または放射線硬化性の有機ポリマー系バインダーの場合には、常温で液状のバインダーを選択することにより、溶剤を存在させずに１００％反応系のバインダー、あるいはこれを非反応性液状樹脂成分で希釈した無溶剤の組成物とすることができる。それにより、被膜の硬化乾燥時に溶媒の蒸発が起こらず、硬化時間が大幅に短縮され、かつ溶媒回収操作が不要となる。 In the case of a light or radiation curable organic polymer binder, by selecting a liquid binder at room temperature, dilute it with a non-reactive liquid resin component or a 100% reactive binder without the presence of a solvent. And a solvent-free composition. As a result, the solvent does not evaporate when the coating is cured and dried, the curing time is greatly shortened, and the solvent recovery operation is not required.
　また、本発明の導電性複合体の導電層には、カーボンナノチューブ以外の導電性有機材料、導電性無機材料、あるいはこれらの材料の組合せをさらに含むことができる。導電性有機材料としては、バッキーボール、カーボンブラック、フラーレン、多種カーボンナノチューブ、ならびにそれらを含む粒子を好ましく挙げることができる。 In addition, the conductive layer of the conductive composite of the present invention can further include a conductive organic material other than carbon nanotubes, a conductive inorganic material, or a combination of these materials. Preferred examples of the conductive organic material include buckyball, carbon black, fullerene, various carbon nanotubes, and particles containing them.
　導電性無機材料としては、アルミニウム、アンチモン、ベリリウム、カドミウム、クロム、コバルト、銅、ドープ金属酸化物、鉄、金、鉛、マンガン、マグネシウム、水銀、金属酸化物、ニッケル、白金、銀、鋼、チタン、亜鉛、ならびにそれらを含む粒子があげられる。好ましくは、酸化インジウムスズ、酸化アンチモンスズ、およびそれらの混合物があげられる。 Conductive inorganic materials include aluminum, antimony, beryllium, cadmium, chromium, cobalt, copper, doped metal oxide, iron, gold, lead, manganese, magnesium, mercury, metal oxide, nickel, platinum, silver, steel, Examples include titanium, zinc, and particles containing them. Preferable examples include indium tin oxide, antimony tin oxide, and mixtures thereof.
　これらの導電性材料を含有させた導電性複合体は、電荷の分散、または移動に非常に有利である。また、これらカーボンナノチューブ以外の導電性材料を含む層とカーボンナノチューブを含む層を積層させてもよい。 The conductive composite containing these conductive materials is very advantageous for charge dispersion or movement. Further, a layer containing a conductive material other than these carbon nanotubes and a layer containing carbon nanotubes may be laminated.
　本発明のカーボンナノチューブ集合体を用いてなる導電層は、優れた透明性を示すので、基材として透明基材を用いた場合、導電性複合体は、優れた透明性を示す。 Since the conductive layer using the carbon nanotube aggregate of the present invention exhibits excellent transparency, when a transparent substrate is used as the substrate, the conductive composite exhibits excellent transparency.
　本発明の導電性複合体の表面抵抗値は１０５Ω／□未満であることが好ましい。表面抵抗値がこの範囲であると、ＥＭＩ／ＲＦＩ（電磁干渉）シールド、低視認性、ポリマーエレクトロニクス（例えば、ＯＬＥＤディスプレイの透明導電層、ＥＬランプ、プラスチックチップ）など透明導電性コーティングの種々の用途に有用である。本発明の導電性複合体の表面抵抗は、導電層の膜厚を制御することにより、種々の用途に合わせて容易に調整可能である。例えば膜厚を厚くすることにより、表面抵抗は低くなり、膜厚を薄くすることにより表面抵抗は高くなる傾向にある。例えば、ＥＭＩ／ＲＦＩシールドの導電性コーティングは、表面抵抗が、１０４Ω／□未満、好ましくは１０１～１０３Ω／□であれば一般に許容される。さらに、透明性の低視認性コーティングは、表面抵抗が、１０３Ω／□未満、好ましくは１０２Ω／□未満であれば一般に許容される。ポリマーエレクトロニクスの場合、表面抵抗値は、通常１０４Ω／□未満、好ましくは１０－２～１００Ω／□の範囲である。したがって、好ましい実施形態では、導電性複合体の表面抵抗は約１０４Ω／□未満である。 The surface resistance value of the conductive composite of the present invention is preferably less than 10 5 Ω / □. When the surface resistance value is within this range, various uses of transparent conductive coating such as EMI / RFI (electromagnetic interference) shield, low visibility, polymer electronics (eg, transparent conductive layer of OLED display, EL lamp, plastic chip) Useful for. The surface resistance of the conductive composite of the present invention can be easily adjusted according to various applications by controlling the film thickness of the conductive layer. For example, increasing the film thickness tends to lower the surface resistance, and reducing the film thickness tends to increase the surface resistance. For example, a conductive coating for an EMI / RFI shield is generally acceptable if the surface resistance is less than 10 4 Ω / □, preferably 10 1 to 10 3 Ω / □. Furthermore, transparent low visibility coatings are generally acceptable if the surface resistance is less than 10 3 Ω / □, preferably less than 10 2 Ω / □. In the case of polymer electronics, the surface resistance value is usually less than 10 4 Ω / □, preferably in the range of 10 −2 to 10 0 Ω / □. Thus, in a preferred embodiment, the conductive composite has a surface resistance of less than about 10 4 Ω / □.
　本発明の導電性複合体は、表面抵抗が１×１０５Ω／□未満であり、かつ、５５０ｎｍの波長の光透過率が以下の条件を満たすことが好ましい
　　導電性複合体の透過率／透明基材の透過率＞０．８５
　好ましくは、表面抵抗が１×１０２Ω／□以上、５×１０４Ω／□未満である。 The conductive composite of the present invention preferably has a surface resistance of less than 1 × 10 5 Ω / □, and the light transmittance at a wavelength of 550 nm satisfies the following conditions: Transmittance / transparency of conductive composite Substrate transmittance> 0.85
Preferably, the surface resistance is 1 × 10 2 Ω / □ or more and less than 5 × 10 4 Ω / □.
　以下、実施例により本発明を具体的に説明するが、下記の実施例は例示のために示すものであって、いかなる意味においても、本発明を限定的に解釈するものとして使用してはならない。 EXAMPLES Hereinafter, the present invention will be specifically described by way of examples. However, the following examples are given for illustrative purposes and should not be used in any way as a limited interpretation of the present invention. .
　実施例中、各種物性評価は以下の方法で行った。 In the examples, various physical properties were evaluated by the following methods.
　［熱分析］
　約１ｍｇの試料を示差熱・熱重量分析装置（島津製作所製　ＤＴＧ－６０Ａ）に設置し、空気中、１０℃／分の昇温速度にて室温から９００℃まで昇温した。そのときのＤＴＡ曲線から発熱による燃焼ピーク温度を読みとった。 [Thermal analysis]
About 1 mg of the sample was placed in a differential thermal / thermogravimetric analyzer (DTG-60A manufactured by Shimadzu Corporation), and the temperature was increased from room temperature to 900 ° C. at a temperature increase rate of 10 ° C./min. The combustion peak temperature due to heat generation was read from the DTA curve at that time.
　また同時に、２００℃から４００℃までの重量減少量と２００℃から９００℃までの重量減少量を測定し、２００℃から９００℃までの重量減少量に対する２００℃から４００℃の間での重量減少量の割合を算出した。 At the same time, the weight loss from 200 ° C. to 400 ° C. and the weight loss from 200 ° C. to 900 ° C. are measured, and the weight loss between 200 ° C. and 400 ° C. with respect to the weight loss from 200 ° C. to 900 ° C. The percentage of quantity was calculated.
　［ラマン分光分析］
　共鳴ラマン分光計（ホリバ　ジョバンイボン製　ＩＮＦ－３００）に粉末試料を設置し、５３２ｎｍのレーザー波長を用いて測定を行った。Ｇ／Ｄ比の測定に際しては、サンプルの異なる３ヶ所について分析を行い、その相加平均を求めた。 [Raman spectroscopy]
A powder sample was placed in a resonance Raman spectrometer (INF-300 manufactured by Horiba Joban Yvon), and measurement was performed using a laser wavelength of 532 nm. When measuring the G / D ratio, analysis was performed on three different locations of the sample, and the arithmetic average was obtained.
　［高分解能透過型電子顕微鏡分析］
　カーボンナノチューブ集合体１ｍｇをエタノール１ｍＬに入れて、約１５分間超音波バスを用いて分散処理を行った。分散した試料をグリッド上に数滴滴下し、乾燥した。このように試料の塗布されたグリッドを透過型電子顕微鏡（日本電子社製　ＪＥＭ－２１００）に設置し、測定を行った。測定倍率は５万倍から５０万倍である。加速電圧は１２０ｋＶである。 [High-resolution transmission electron microscope analysis]
1 mg of the carbon nanotube aggregate was placed in 1 mL of ethanol, and dispersion treatment was performed using an ultrasonic bath for about 15 minutes. A few drops of the dispersed sample were dropped on the grid and dried. The grid thus coated with the sample was placed in a transmission electron microscope (JEM-2100, manufactured by JEOL Ltd.) and measured. The measurement magnification is 50,000 times to 500,000 times. The acceleration voltage is 120 kV.
　［透明導電性フィルム作製］
　カーボンナノチューブ集合体分散液３００μＬにメタノール／水（重量比１／１）をぬれ剤として３００μＬ添加後、ポリエチレンテレフタレート（ＰＥＴ）フィルム（東レ（株）社製（ルミラー（登録商標）Ｕ３６））上にバーコーター（Ｎｏ．８、塗布厚み１２μｍ）を用いて塗布し、風乾した後、蒸留水にてリンスし、６０℃乾燥機内で２分間乾燥させ、カーボンナノチューブ集合体を固定化した。 [Transparent conductive film production]
After adding 300 μL of methanol / water (weight ratio 1/1) as a wetting agent to 300 μL of the carbon nanotube aggregate dispersion liquid, on a polyethylene terephthalate (PET) film (manufactured by Toray Industries, Inc. (Lumirror (registered trademark) U36)). After coating using a bar coater (No. 8, coating thickness 12 μm), air drying, rinsing with distilled water, and drying in a 60 ° C. dryer for 2 minutes to immobilize the carbon nanotube aggregate.
　［光透過率測定］
　測定サンプルを分光光度計（日立製作所　Ｕ－２１００）に装填し、波長５５０ｎｍでの光透過率を測定した。 [Light transmittance measurement]
The measurement sample was loaded into a spectrophotometer (Hitachi U-2100), and the light transmittance at a wavelength of 550 nm was measured.
　［表面抵抗測定］
　表面抵抗値はＪＩＳ　Ｋ７１４９（１９９４年１２月制定）準処の４端子４探針法を用い、ロレスタＥＰ　ＭＣＰ－Ｔ３６０（（株）ダイアインスツルメンツ社製）を用いて測定した。高抵抗測定の際は、ハイレスターＵＰ　ＭＣＰ－ＨＴ４５０（ダイアインスツルメンツ製、１０Ｖ、１０秒）を用いて測定した。 [Surface resistance measurement]
The surface resistance value was measured using a 4-terminal 4-probe method according to JIS K7149 (established in December 1994) and a Loresta EP MCP-T360 (manufactured by Dia Instruments Co., Ltd.). When measuring high resistance, it was measured using Hiresta UP MCP-HT450 (manufactured by Dia Instruments, 10 V, 10 seconds).
　＜実施例１＞
　（マグネシアへの触媒金属塩の担持）
　クエン酸アンモニウム鉄（和光純薬工業社製）２．４６ｇをメタノール（関東化学社製）５００ｍＬに溶解した。この溶液に、マグネシア（岩谷化学工業社製）を１００ｇ加え、室温にて６０分間攪拌し、その後エバポレーターを使用して、水浴温４０℃から６０℃で減圧条件にてメタノールを除去した。その後、１２０℃乾燥機にて２時間乾燥し、マグネシア粉末に触媒金属塩が担持された固体触媒を得た。この時の触媒のかさ密度は０．５８ｇ／ｍＬであった。 <Example 1>
(Supporting catalytic metal salt on magnesia)
2.46 g of ammonium iron citrate (Wako Pure Chemical Industries, Ltd.) was dissolved in 500 mL of methanol (Kanto Chemical Co., Ltd.). To this solution, 100 g of magnesia (manufactured by Iwatani Chemical Industry Co., Ltd.) was added and stirred at room temperature for 60 minutes, and then methanol was removed under reduced pressure conditions at a water bath temperature of 40 ° C. to 60 ° C. using an evaporator. Then, it dried for 2 hours with a 120 degreeC dryer, and obtained the solid catalyst by which the catalyst metal salt was carry | supported by the magnesia powder. At this time, the bulk density of the catalyst was 0.58 g / mL.
　（２層カーボンナノチューブの合成）
　図２に示した縦型反応器でカーボンナノチューブを合成した。 (Synthesis of double-walled carbon nanotube)
Carbon nanotubes were synthesized in the vertical reactor shown in FIG.
　反応器１００は内径７５ｍｍ、長さは１７００ｍｍの円筒形石英管である。中央部に石英焼結板１０１を具備し、石英管下方部には、不活性ガスおよび原料ガス供給ライン１０４、上部には廃ガスライン１０５および、密閉型触媒供給機１０２および触媒投入ライン１０３を具備する。さらに、反応器を任意温度に保持できるように、反応器の円周を取り囲む加熱器１０６を具備する。加熱器１０６には装置内の流動状態が確認できるよう点検口１０７が設けられている。 The reactor 100 is a cylindrical quartz tube having an inner diameter of 75 mm and a length of 1700 mm. A quartz sintered plate 101 is provided at the center, an inert gas and raw material gas supply line 104 at the lower part of the quartz tube, a waste gas line 105 at the upper part, a sealed catalyst feeder 102 and a catalyst charging line 103. It has. In addition, a heater 106 is provided that surrounds the circumference of the reactor so that the reactor can be maintained at an arbitrary temperature. The heater 106 is provided with an inspection port 107 so that the flow state in the apparatus can be confirmed.
　触媒１３２ｇを取り、触媒投入ライン１０３を通して、石英焼結板１０１上に触媒をセットした。次いで、原料ガス供給ライン１０４から窒素ガスを１０．０Ｌ／分で供給開始した。反応器内を窒素ガス雰囲気下とした後、温度を８５０℃に加熱した（昇温時間３０分）。 132 g of catalyst was taken, and the catalyst was set on the quartz sintered plate 101 through the catalyst charging line 103. Subsequently, supply of nitrogen gas from the source gas supply line 104 was started at 10.0 L / min. After the inside of the reactor was placed in a nitrogen gas atmosphere, the temperature was heated to 850 ° C. (temperature rising time 30 minutes).
　８５０℃に到達した後、温度を保持し、原料ガス供給ライン１０４の窒素流量を１６．５Ｌ／分に上げ、石英焼結板上の固体触媒の流動化を開始させた。加熱炉点検口１０７から流動化を確認した後、さらにメタンを０．７８Ｌ／分（メタン濃度４．５体積％、線速６．５ｃｍ／ｓｅｃ）で反応器に供給開始した。該混合ガスを６０分供給した後、窒素ガスのみの流通に切り替え、合成を終了させた。この時のメタンと触媒の接触時間は１．６９×１０－１ｇ・ｍｉｎ／ｍＬであった。 After reaching 850 ° C., the temperature was maintained, the nitrogen flow rate of the raw material gas supply line 104 was increased to 16.5 L / min, and fluidization of the solid catalyst on the quartz sintered plate was started. After confirming fluidization from the heating furnace inspection port 107, methane was further fed to the reactor at 0.78 L / min (methane concentration: 4.5 vol%, linear velocity: 6.5 cm / sec). After supplying the mixed gas for 60 minutes, the flow was switched to a flow of only nitrogen gas to complete the synthesis. At this time, the contact time between methane and the catalyst was 1.69 × 10 −1 g · min / mL.
　加熱を停止させ室温まで放置し、反応器から触媒とカーボンナノチューブ集合体を含有する組成物を取り出した。得られたカーボンナノチューブ集合体を以下の工程に供した。 The heating was stopped and the mixture was allowed to stand at room temperature, and the composition containing the catalyst and the carbon nanotube aggregate was taken out from the reactor. The obtained carbon nanotube aggregate was subjected to the following steps.
　得られたカーボンナノチューブ集合体を前記の方法で熱分析した。燃焼ピーク温度は４８０℃であった。 The obtained carbon nanotube aggregate was subjected to thermal analysis by the method described above. The combustion peak temperature was 480 ° C.
　（カーボンナノチューブ集合体の焼成、精製処理）
　カーボンナノチューブ集合体３０ｇを磁性皿（１５０φ）に取り、大気下、４５０℃に加熱したマッフル炉（ヤマト科学社製、ＦＰ４１）に入れ、３時間保持した後、自然放冷した。その後、上記のカーボンナノチューブから触媒を除去するため、次のように精製処理を行った。カーボンナノチューブを６Ｎの塩酸水溶液に添加し、８０℃のウォーターバス内で１時間攪拌した。孔径１μｍのフィルターを用いてろ過して回収物を得た。この操作をさらに２回繰り返し、最後に数回水洗した後、ろ過物を１２０℃のオーブンで一晩乾燥することで、マグネシアおよび触媒金属を除去でき、カーボンナノチューブを精製することができた。 (Baking and refining of carbon nanotube aggregates)
30 g of the carbon nanotube aggregate was placed in a magnetic dish (150φ), placed in a muffle furnace (FP41, manufactured by Yamato Kagaku Co., Ltd.) heated to 450 ° C. in the atmosphere, and held for 3 hours, and then allowed to cool naturally. Then, in order to remove a catalyst from said carbon nanotube, the refinement | purification process was performed as follows. Carbon nanotubes were added to a 6N hydrochloric acid aqueous solution and stirred in a water bath at 80 ° C. for 1 hour. Filtration was performed using a filter having a pore size of 1 μm to obtain a recovered product. This operation was repeated two more times, and finally, after washing several times with water, the filtrate was dried in an oven at 120 ° C. overnight, so that magnesia and catalytic metal could be removed, and carbon nanotubes could be purified.
　（カーボンナノチューブ集合体の熱分析）
　得られたカーボンナノチューブ集合体の熱分析を行った。燃焼ピーク温度は６６４℃であった。また、２００℃から４００℃までの重量減少量は、２００℃から９００℃までの重量減少量の５％であることがわかった。 (Thermal analysis of carbon nanotube aggregates)
The obtained carbon nanotube aggregate was subjected to thermal analysis. The combustion peak temperature was 664 ° C. Moreover, it turned out that the weight reduction amount from 200 degreeC to 400 degreeC is 5% of the weight reduction amount from 200 degreeC to 900 degreeC.
　（カーボンナノチューブ集合体の高分解能透過型電子顕微鏡分析）
　上記のようにして得たカーボンナノチューブ集合体を高分解能透過型電子顕微鏡で観察したところ、図３に示すように、カーボンナノチューブはきれいなグラファイト層で構成されており、層数が２層のカーボンナノチューブが観察された。またカーボンナノチューブ１００本中の８０％以上（８５本）を２層のカーボンナノチューブが占めていた。また３層以上のカーボンナノチューブは１０％以下（７本）であった。 (High-resolution transmission electron microscope analysis of carbon nanotube aggregates)
The carbon nanotube aggregate obtained as described above was observed with a high-resolution transmission electron microscope. As shown in FIG. 3, the carbon nanotube was composed of a clean graphite layer, and the number of the carbon nanotubes was two. Was observed. Two-layer carbon nanotubes occupied 80% or more (85) of 100 carbon nanotubes. The number of carbon nanotubes in three or more layers was 10% or less (seven).
　（カーボンナノチューブ集合体の共鳴ラマン分光分析）
　上記のようにして得たカーボンナノチューブ集合体を、ラマン分光測定した。その結果、図４に示すように、波長５３２ｎｍのラマン分光分析において、Ｇ／Ｄ比は５３と、グラファイト化度の高い高品質２層カーボンナノチューブであることがわかった。 (Resonance Raman spectroscopic analysis of carbon nanotube aggregates)
The aggregate of carbon nanotubes obtained as described above was subjected to Raman spectroscopic measurement. As a result, as shown in FIG. 4, in the Raman spectroscopic analysis at a wavelength of 532 nm, it was found that the G / D ratio was 53, which is a high-quality double-walled carbon nanotube having a high degree of graphitization.
　（カーボンナノチューブ集合体の体積抵抗率測定）
　上記のようにして得たカーボンナノチューブ集合体２０ｍｇをＮ－メチルピロリドン１６ｍＬと混合し、超音波ホモジナイザーを用いて２０Ｗで２０分超音波照射した後、エタノール１０ｍＬと混合し、内径３５ｍｍφのろ過器を用いて吸引ろ過し、このろ取物をろ過器とろ取に用いたフィルターごと６０℃で２時間、乾燥機中で乾燥した。カーボンナノチューブ膜が形成されたフィルターを取り外し、フィルターごと膜厚みを測定し、フィルターの膜厚みを差し引いたところ、カーボンナノチューブ膜の厚みは６５μｍであった。フィルターはＯＭＮＩＰＯＲＥＭＥＭＢＲＡＮＥ　ＦＩＬＴＥＲＳ、ＦＩＬＴＥＲ　ＴＹＰＥ：　１．０μｍ　ＪＡ、４７ｍｍφを使用した。得られたカーボンナノチューブ膜をＪＩＳＫ７１４９準処の４端子４探針法を用いてロレスタＥＰ　ＭＣＰ－Ｔ３６０（（株）ダイアインスツルメンツ社製）にて測定したところ、表面抵抗値は０．２４９Ω／□であった。したがって体積抵抗率は１．６２×１０－３Ω・ｃｍである。 (Measurement of volume resistivity of carbon nanotube aggregate)
20 mg of the carbon nanotube aggregate obtained as described above was mixed with 16 mL of N-methylpyrrolidone, subjected to ultrasonic irradiation at 20 W for 20 minutes using an ultrasonic homogenizer, then mixed with 10 mL of ethanol, and a filter having an inner diameter of 35 mmφ was added. Then, the filtered product and the filter used for filtration were dried at 60 ° C. for 2 hours in a dryer. When the filter on which the carbon nanotube film was formed was removed, the film thickness was measured together with the filter, and the film thickness of the filter was subtracted, the thickness of the carbon nanotube film was 65 μm. The filter used was OMNIPOREMBRANE FILTERS, FILTER TYPE: 1.0 μm JA, 47 mmφ. When the obtained carbon nanotube film was measured by Loresta EP MCP-T360 (manufactured by Dia Instruments Co., Ltd.) using a four-terminal four-probe method according to JIS K7149, the surface resistance was 0.249Ω / □. there were. Accordingly, the volume resistivity is 1.62 × 10 −3 Ω · cm.
　（カーボンナノチューブ集合体の表面組成解析）
　Ｘ線光電子分光法（ＸＰＳ）にて表面組成を評価した。使用した機器はＥＳＣＡＬＡＢ２２０ｉＸＬで、励起Ｘ線はＭｏｎｏｃｈｒｏｍａｔｉｃ　ＡｌＫα１，２線、Ｘ線径は１０００μｍである。光電子脱出角度は９０°である。その結果、炭素原子に対する酸素原子の割合は２．５％であった。 (Surface composition analysis of carbon nanotube aggregates)
The surface composition was evaluated by X-ray photoelectron spectroscopy (XPS). The equipment used is ESCALAB 220iXL, the excitation X-ray is Monochromatic AlKα 1 , 2 and the X-ray diameter is 1000 μm. The photoelectron escape angle is 90 °. As a result, the ratio of oxygen atoms to carbon atoms was 2.5%.
　（カーボンナノチューブ集合体分散液調製）
　５０ｍＬの容器に上記カーボンナノチューブ集合体１０ｍｇおよびポリスチレンスルホン酸ナトリウム水溶液（アルドリッチ社製、３０重量％、重量平均分子量２０万）１００ｍｇを量りとり、蒸留水９．９３ｍＬを加えて、超音波ホモジナイザー出力２５Ｗ、２０分間で氷冷下分散処理し、カーボンナノチューブ集合体分散液を調製した。調製した液には凝集体は目視では確認できず、カーボンナノチューブ集合体はよく分散していた。得られた液を高速遠心分離機にて１００００Ｇ、１５分遠心処理し、上清を得た。この時の上清のカーボンナノチューブ濃度は０．０９５重量％であった。 (Preparation of carbon nanotube aggregate dispersion)
Weigh 10 mg of the carbon nanotube aggregate and 100 mg of polystyrene sulfonate aqueous solution (Aldrich, 30% by weight, 200,000 in weight average molecular weight) into a 50 mL container, add 9.93 mL of distilled water, and output an ultrasonic homogenizer of 25 W. Then, the dispersion treatment was carried out for 20 minutes under ice cooling to prepare a carbon nanotube aggregate dispersion. Aggregates could not be visually confirmed in the prepared liquid, and the carbon nanotube aggregates were well dispersed. The obtained liquid was centrifuged at 10,000 G for 15 minutes with a high-speed centrifuge to obtain a supernatant. At this time, the concentration of carbon nanotubes in the supernatant was 0.095% by weight.
　上記で得たカーボンナノチューブ集合体分散液を用いて、前記の方法で透明導電性フィルムを得た。得られた透明導電性フィルムの表面抵抗値は１．６×１０３Ω／□、光透過率は８５％（透明導電性フィルム８５％／ＰＥＴフィルム９０．７％＝０．９４）であり、高い導電性および、透明性を示した。 Using the carbon nanotube aggregate dispersion obtained above, a transparent conductive film was obtained by the above method. The surface resistance value of the obtained transparent conductive film is 1.6 × 10 3 Ω / □, and the light transmittance is 85% (transparent conductive film 85% / PET film 90.7% = 0.94). It showed high conductivity and transparency.
　＜実施例２＞
　（マグネシアへの触媒金属塩の担持）
　実施例１と同様に行い、触媒金属塩をマグネシアに担持した。 <Example 2>
(Supporting catalytic metal salt on magnesia)
In the same manner as in Example 1, the catalyst metal salt was supported on magnesia.
　（２層カーボンナノチューブの合成）
　上記触媒を用いて、反応中の窒素を１１．０Ｌ／分、メタンを０．５２Ｌ／分（メタン濃度４．５体積％、線速４．３ｃｍ／ｓｅｃ）で流通させる以外は実施例１と同様な方法でカーボンナノチューブを合成した。この時のメタンと触媒の接触時間は２．５４×１０－１ｇ・ｍｉｎ／ｍＬであった。得られたカーボンナノチューブ集合体を前記の方法で熱分析した。燃焼ピーク温度は４７５℃であった。 (Synthesis of double-walled carbon nanotube)
Example 1 except that the above catalyst was used to circulate nitrogen during the reaction at 11.0 L / min and methane at 0.52 L / min (methane concentration: 4.5 vol%, linear velocity: 4.3 cm / sec). Carbon nanotubes were synthesized by the same method. At this time, the contact time of methane and the catalyst was 2.54 × 10 −1 g · min / mL. The obtained carbon nanotube aggregate was subjected to thermal analysis by the method described above. The combustion peak temperature was 475 ° C.
　（カーボンナノチューブ集合体の焼成、精製処理）
　実施例１と同様の操作を行った。 (Baking and refining of carbon nanotube aggregates)
The same operation as in Example 1 was performed.
　（カーボンナノチューブ集合体の高分解能透過型電子顕微鏡分析）
　上記のようにして得たカーボンナノチューブ集合体を高分解能透過型電子顕微鏡で観察したところ、カーボンナノチューブはきれいなグラファイト層で構成されており、層数が２層のカーボンナノチューブが観察された。またカーボンナノチューブ１００本中の７３％（７３本）を２層のカーボンナノチューブが占めていた。また３層以上のカーボンナノチューブは１０％以下（２本）であった。 (High-resolution transmission electron microscope analysis of carbon nanotube aggregates)
When the aggregate of carbon nanotubes obtained as described above was observed with a high-resolution transmission electron microscope, the carbon nanotubes were composed of a clean graphite layer, and carbon nanotubes with two layers were observed. Two-layer carbon nanotubes accounted for 73% (73) of 100 carbon nanotubes. Further, the number of carbon nanotubes in three or more layers was 10% or less (two).
　（カーボンナノチューブ集合体の共鳴ラマン分光分析）
　上記のようにして得たカーボンナノチューブ集合体を、ラマン分光測定した。その結果、波長５３２ｎｍのラマン分光分析でＧ／Ｄ比は３８と、グラファイト化度の高い高品質２層カーボンナノチューブであることがわかった。 (Resonance Raman spectroscopic analysis of carbon nanotube aggregates)
The aggregate of carbon nanotubes obtained as described above was subjected to Raman spectroscopic measurement. As a result, it was found by Raman spectroscopic analysis at a wavelength of 532 nm that the G / D ratio was 38, which is a high-quality double-walled carbon nanotube with a high degree of graphitization.
　（カーボンナノチューブ集合体の体積抵抗率測定）
　上記のようにして得たカーボンナノチューブ集合体の体積抵抗率測定を実施例１と同様にして測定した。カーボンナノチューブ膜の厚みは７１．５μｍ、表面抵抗値は０．３８３Ω／□であった。したがって体積抵抗率は２．７４×１０－３Ω・ｃｍである。 (Measurement of volume resistivity of carbon nanotube aggregate)
The volume resistivity of the carbon nanotube aggregate obtained as described above was measured in the same manner as in Example 1. The carbon nanotube film had a thickness of 71.5 μm and a surface resistance value of 0.383Ω / □. Accordingly, the volume resistivity is 2.74 × 10 −3 Ω · cm.
　（カーボンナノチューブ集合体分散液調製）
　実施例１と同様の操作を行いカーボンナノチューブ集合体の分散液を調製した。この時の上清のカーボンナノチューブ濃度は０．０９０重量％であった。 (Preparation of carbon nanotube aggregate dispersion)
The same operation as in Example 1 was performed to prepare a carbon nanotube aggregate dispersion. At this time, the concentration of carbon nanotubes in the supernatant was 0.090% by weight.
　上記で得たカーボンナノチューブ集合体分散液を用いて、前記の方法で透明導電性フィルムを得た。得られた透明導電性フィルムの表面抵抗値は１．７×１０３Ω／□、光透過率は８５％（透明導電性フィルム８５％／ＰＥＴフィルム９０．７％＝０．９４）であり、高い導電性および透明性を示した。
＜比較例１＞
（マグネシアへの触媒金属塩の担持）
　実施例１と同様の操作を行い、固体触媒を得た。 Using the carbon nanotube aggregate dispersion obtained above, a transparent conductive film was obtained by the above method. The surface resistance value of the obtained transparent conductive film is 1.7 × 10 3 Ω / □, and the light transmittance is 85% (transparent conductive film 85% / PET film 90.7% = 0.94). It showed high conductivity and transparency.
<Comparative Example 1>
(Supporting catalytic metal salt on magnesia)
The same operation as in Example 1 was performed to obtain a solid catalyst.
　（２層カーボンナノチューブの合成）
　反応中メタンを０．７８Ｌ／分（メタン濃度１００体積％、線速０．３９ｃｍ／ｓｅｃ）で流通させ、窒素ガスを流さないこととした以外は実施例１と同様の操作を行ない、触媒とカーボンナノチューブ集合体を含有する組成物を取り出した。得られたカーボンナノチューブ集合体を以下の工程に供した。得られたカーボンナノチューブ集合体を前記の方法で熱分析した。燃焼ピーク温度は５６９℃であった。 (Synthesis of double-walled carbon nanotube)
During the reaction, methane was circulated at 0.78 L / min (methane concentration: 100 vol%, linear velocity: 0.39 cm / sec), and the same operation as in Example 1 was carried out except that nitrogen gas was not flown. A composition containing an aggregate of carbon nanotubes was taken out. The obtained carbon nanotube aggregate was subjected to the following steps. The obtained carbon nanotube aggregate was subjected to thermal analysis by the method described above. The combustion peak temperature was 569 ° C.
　（カーボンナノチューブ集合体の焼成、精製処理）
　実施例１と同様の操作を行った。 (Baking and refining of carbon nanotube aggregates)
The same operation as in Example 1 was performed.
　（カーボンナノチューブ集合体の共鳴ラマン分光分析）
　上記のようにして得たカーボンナノチューブ集合体を、ラマン分光測定した。その結果、図４に示すように、波長５３２ｎｍのラマン分光分析において、ラマンＧ／Ｄ比は３であった。 (Resonance Raman spectroscopic analysis of carbon nanotube aggregates)
The aggregate of carbon nanotubes obtained as described above was subjected to Raman spectroscopic measurement. As a result, as shown in FIG. 4, the Raman G / D ratio was 3 in the Raman spectroscopic analysis at a wavelength of 532 nm.
　（カーボンナノチューブ集合体の体積抵抗率測定）
　上記のようにして得たカーボンナノチューブ集合体の体積抵抗率測定を実施例１と同様にして測定した。カーボンナノチューブ膜の厚みは１０５．５μｍ、表面抵抗値は５３．４５Ω／□であった。したがって体積抵抗率は５．６４×１０－１Ω・ｃｍである。 (Measurement of volume resistivity of carbon nanotube aggregate)
The volume resistivity of the carbon nanotube aggregate obtained as described above was measured in the same manner as in Example 1. The carbon nanotube film had a thickness of 105.5 μm and a surface resistance value of 53.45Ω / □. Accordingly, the volume resistivity is 5.64 × 10 −1 Ω · cm.
　＜比較例２＞
（マグネシアへの触媒金属塩の担持）
　実施例１と同様の操作を行い、固体触媒を得た。 <Comparative example 2>
(Supporting catalytic metal salt on magnesia)
The same operation as in Example 1 was performed to obtain a solid catalyst.
　（２層カーボンナノチューブの合成）
　反応中メタンを９ｍＬ／分（メタン濃度４．５体積％、線速０．１１ｃｍ／ｓｅｃ）、窒素を２００ｍＬ／分流通した以外は実施例１と同様の操作を行ない、触媒とカーボンナノチューブ集合体を含有する組成物を取り出した。得られたカーボンナノチューブ集合体を以下の工程に供した。得られたカーボンナノチューブ集合体を前記の方法で熱分析した。燃焼ピーク温度は５１７℃であった。 (Synthesis of double-walled carbon nanotube)
During the reaction, the same operation as in Example 1 was carried out except that methane was supplied at 9 mL / min (methane concentration: 4.5 vol%, linear velocity: 0.11 cm / sec) and nitrogen was supplied at 200 mL / min. The composition containing was taken out. The obtained carbon nanotube aggregate was subjected to the following steps. The obtained carbon nanotube aggregate was subjected to thermal analysis by the method described above. The combustion peak temperature was 517 ° C.
　（カーボンナノチューブ集合体の焼成、精製処理）
　実施例１と同様の操作を行った。 (Baking and refining of carbon nanotube aggregates)
The same operation as in Example 1 was performed.
　（カーボンナノチューブ集合体の共鳴ラマン分光分析）
　上記のようにして得たカーボンナノチューブ集合体を、ラマン分光測定した。その結果、図４に示すように、波長５３２ｎｍのラマン分光分析において、ラマンＧ／Ｄ比は２０であった。 (Resonance Raman spectroscopic analysis of carbon nanotube aggregates)
The aggregate of carbon nanotubes obtained as described above was subjected to Raman spectroscopic measurement. As a result, as shown in FIG. 4, the Raman G / D ratio was 20 in the Raman spectroscopic analysis at a wavelength of 532 nm.
　（カーボンナノチューブ集合体の体積抵抗率測定）
　上記のようにして得たカーボンナノチューブ集合体の体積抵抗率測定を実施例１と同様にして測定した。カーボンナノチューブ膜の厚みは６５．３μｍ、表面抵抗値は５．８９Ω／□であった。したがって体積抵抗率は３．８５×１０－２Ω・ｃｍである。 (Measurement of volume resistivity of carbon nanotube aggregate)
The volume resistivity of the carbon nanotube aggregate obtained as described above was measured in the same manner as in Example 1. The carbon nanotube film had a thickness of 65.3 μm and a surface resistance value of 5.89 Ω / □. Therefore, the volume resistivity is 3.85 × 10 −2 Ω · cm.
　＜比較例３＞
　ナノテクポート社製２層カーボンナノチューブのラマンＧ／Ｄ比（５３２ｎｍ）は１４であった。実施例１と同様の方法でカーボンナノチューブ膜を作製したところ、カーボンナノチューブ膜の厚みは２２．０μｍ、表面抵抗値は３９．６５Ω／□であった。したがって体積抵抗率は８．７２×１０－２Ω・ｃｍであった。　 <Comparative Example 3>
The Raman G / D ratio (532 nm) of the double-walled carbon nanotubes manufactured by Nanotechport was 14. When a carbon nanotube film was produced in the same manner as in Example 1, the carbon nanotube film had a thickness of 22.0 μm and a surface resistance value of 39.65Ω / □. Therefore, the volume resistivity was 8.72 × 10 −2 Ω · cm.
　＜比較例４＞
　アーク放電法により製造された名城ナノカーボン社製単層カーボンナノチューブ（単層カーボンナノチューブが６７％であった）のラマンＧ／Ｄ比（５３２ｎｍ）は４３であった。実施例１と同様の方法でカーボンナノチューブ膜を作製したところ、カーボンナノチューブ膜の厚みは６２．０μｍ、表面抵抗値は１．８４２Ω／□であった。したがって体積抵抗率は１．１４×１０－２Ω・ｃｍであった。 <Comparative Example 4>
The Raman G / D ratio (532 nm) of single-walled carbon nanotubes manufactured by the arc discharge method (single-walled carbon nanotubes was 67%) manufactured by Meijo Nanocarbon was 43. When a carbon nanotube film was produced by the same method as in Example 1, the carbon nanotube film had a thickness of 62.0 μm and a surface resistance value of 1.842 Ω / □. Therefore, the volume resistivity was 1.14 × 10 −2 Ω · cm.
　本発明によれば、体積抵抗率が低く、高品質で、かつ、分散性の良好な２層カーボンナノチューブ集合体が得られる。また、本発明のカーボンナノチューブ集合体からえられる成形体、組成物および導電性複合体は、良好な性能を発揮する。 According to the present invention, an aggregate of double-walled carbon nanotubes having a low volume resistivity, high quality, and good dispersibility can be obtained. In addition, the molded product, composition and conductive composite obtained from the carbon nanotube aggregate of the present invention exhibit good performance.
１　　反応器
２　　触媒を置く台
３　　触媒
４　　触媒以外の物体と触媒の混合物
５　　触媒
１００　　反応器
１０１　　石英焼結板
１０２　　密閉型触媒供給機
１０３　　触媒投入ライン
１０４　　原料ガス供給ライン
１０５　　廃ガスライン
１０６　　加熱器
１０７　　点検口
１０８　　触媒 DESCRIPTION OF SYMBOLS 1 Reactor 2 Stand which puts catalyst 3 Catalyst 4 Mixture of objects and catalyst other than catalyst 5 Catalyst 100 Reactor 101 Quartz sintered plate 102 Sealed catalyst feeder 103 Catalyst input line 104 Raw gas supply line 105 Waste gas line 106 Heating 107 Inspection port 108 Catalyst

Claims (18)

  1. 以下の（１）～（４）の条件を全て満たすカーボンナノチューブ集合体；
    （１）カーボンナノチューブ集合体の体積抵抗率が１×１０－４Ω・ｃｍ以上、１×１０－２Ω・ｃｍ以下；
    （２）カーボンナノチューブ集合体中のカーボンナノチューブの５０％以上が２層カーボンナノチューブ；
    （３）カーボンナノチューブ集合体の測定波長５３２ｎｍにおけるラマンＧ／Ｄ比が３０以上、２００以下；
    （４）カーボンナノチューブ集合体の燃焼ピーク温度が５５０℃以上、７００℃以下。     An aggregate of carbon nanotubes that satisfies all of the following conditions (1) to (4):
    (1) The volume resistivity of the carbon nanotube aggregate is 1 × 10 −4 Ω · cm or more and 1 × 10 −2 Ω · cm or less;
    (2) 50% or more of the carbon nanotubes in the aggregate of carbon nanotubes are double-walled carbon nanotubes;
    (3) The Raman G / D ratio of the carbon nanotube aggregate at a measurement wavelength of 532 nm is 30 or more and 200 or less;
    (4) The combustion peak temperature of the carbon nanotube aggregate is 550 ° C. or higher and 700 ° C. or lower.
  2. カーボンナノチューブ集合体中の３層以上のカーボンナノチューブが、カーボンナノチューブ全体の１０％以下である請求項１に記載のカーボンナノチューブ集合体。 The carbon nanotube aggregate according to claim 1, wherein the carbon nanotube aggregate of three or more layers in the carbon nanotube aggregate is 10% or less of the total carbon nanotube.
  3. 炭素原子に対する酸素原子の割合が４％未満である請求項１または２に記載のカーボンナノチューブ集合体。 The aggregate of carbon nanotubes according to claim 1 or 2, wherein the ratio of oxygen atoms to carbon atoms is less than 4%.
  4. １０℃／ｍｉｎで昇温した時の熱重量測定における２００℃から４００℃の重量減少率が５％以下である請求項１から３のいずれか１項に記載のカーボンナノチューブ集合体。 The aggregate of carbon nanotubes according to any one of claims 1 to 3, wherein a weight reduction rate from 200 ° C to 400 ° C in thermogravimetry when the temperature is raised at 10 ° C / min is 5% or less.
  5. 請求項１から４のいずれかに記載のカーボンナノチューブ集合体からなる成形体。 The molded object which consists of a carbon nanotube aggregate in any one of Claim 1 to 4.
  6. 請求項１から４に記載のカーボンナノチューブ集合体を含む組成物。 A composition comprising the carbon nanotube aggregate according to claim 1.
  7. 液状の分散媒にカーボンナノチューブ集合体が分散している請求項６記載の組成物。 The composition according to claim 6, wherein the aggregate of carbon nanotubes is dispersed in a liquid dispersion medium.
  8. さらに界面活性剤、導電性高分子および非導電性高分子から選択される一種以上を含有する請求項６または７記載の組成物。 Furthermore, the composition of Claim 6 or 7 containing 1 or more types selected from surfactant, a conductive polymer, and a nonelectroconductive polymer.
  9. カーボンナノチューブ集合体の含有量が０．０１重量％から２０重量％である請求項６から８のいずれか１項に記載の組成物。 The composition according to any one of claims 6 to 8, wherein a content of the carbon nanotube aggregate is 0.01 wt% to 20 wt%.
  10. 請求項６記載の組成物からなる成形体。 The molded object which consists of a composition of Claim 6.
  11. 請求項１から４のいずれかに記載のカーボンナノチューブ集合体を含む導電層が基材上に形成された導電性複合体。 A conductive composite in which a conductive layer containing the carbon nanotube aggregate according to any one of claims 1 to 4 is formed on a substrate.
  12. 前記基材がフィルムである請求項１１記載の導電性複合体。 The conductive composite according to claim 11, wherein the substrate is a film.
  13. 基材が透明基材であり、かつ以下の（１）および（２）の条件を満たす請求項１２記載の導電性複合体；
    （１）表面抵抗が１×１０５Ω／□未満；
    （２）５５０ｎｍの波長の光透過率が以下の条件を満たす
    　　導電性複合体の透過率／透明基材の透過率＞０．８５。     The conductive composite according to claim 12, wherein the substrate is a transparent substrate and satisfies the following conditions (1) and (2):
    (1) The surface resistance is less than 1 × 10 5 Ω / □;
    (2) Light transmittance at a wavelength of 550 nm satisfying the following conditions: transmittance of conductive composite / transmittance of transparent substrate> 0.85.
  14. 反応器中で、原料ガスと触媒を接触させることによりカーボンナノチューブ集合体を製造する方法であって、メタンを濃度１０体積％以下で含む原料ガスを線速４ｃｍ／ｓｅｃ以上、１５ｃｍ／ｓｅｃ以下で流通させ、触媒と５００～１２００℃で接触させるカーボンナノチューブ集合体の製造方法。 A method for producing an aggregate of carbon nanotubes by bringing a raw material gas into contact with a catalyst in a reactor, wherein a raw material gas containing methane at a concentration of 10% by volume or less is fed at a linear velocity of 4 cm / sec to 15 cm / sec. A method for producing a carbon nanotube aggregate that is allowed to flow and contact with a catalyst at 500 to 1200 ° C.
  15. 前記触媒のかさ密度が０．３０ｇ／ｍＬ以上、２．００ｇ／ｍＬ以下である請求項１４に記載のカーボンナノチューブ集合体の製造方法。 The method for producing a carbon nanotube aggregate according to claim 14, wherein a bulk density of the catalyst is 0.30 g / mL or more and 2.00 g / mL or less.
  16. メタンと触媒の接触時間が８．０×１０－２ｇ・ｍｉｎ／ｍＬ以上、１．０×１００ｇ・ｍｉｎ／ｍＬ以下である請求項１４または１５に記載のカーボンナノチューブ集合体の製造方法。 The method for producing an aggregate of carbon nanotubes according to claim 14 or 15, wherein the contact time between methane and the catalyst is 8.0 x 10 -2 g · min / mL or more and 1.0 x 10 0 g · min / mL or less. .
  17. 原料ガスと触媒を接触させて得られたカーボンナノチューブ集合体をさらに気相酸化する工程を含む請求項１４から１６のいずれかに記載のカーボンナノチューブ集合体の製造方法。 The method for producing a carbon nanotube aggregate according to any one of claims 14 to 16, further comprising a step of subjecting the carbon nanotube aggregate obtained by bringing the raw material gas and the catalyst into contact with each other to vapor phase oxidation.
  18. 気相酸化後のカーボンナノチューブ集合体の測定波長５３２ｎｍにおけるラマンＧ／Ｄ比が３０以上になるまで気相酸化する請求項１７記載のカーボンナノチューブ集合体の製造方法。 The method for producing a carbon nanotube aggregate according to claim 17, wherein the carbon nanotube aggregate after vapor phase oxidation is vapor phase oxidized until the Raman G / D ratio at a measurement wavelength of 532 nm reaches 30 or more.
PCT/JP2009/061675 2008-06-27 2009-06-26 Carbon nanotube assembly and method for producing same WO2009157529A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2008-169670 2008-06-27
JP2008169670A JP2010006663A (en) 2008-06-27 2008-06-27 Carbon nanotube assembly, method for producing the same, shaped body, composition and composite

Publications (1)

Publication Number Publication Date
WO2009157529A1 true WO2009157529A1 (en) 2009-12-30

Family

ID=41444589

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2009/061675 WO2009157529A1 (en) 2008-06-27 2009-06-26 Carbon nanotube assembly and method for producing same

Country Status (2)

Country Link
JP (1) JP2010006663A (en)
WO (1) WO2009157529A1 (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010101205A1 (en) * 2009-03-04 2010-09-10 東レ株式会社 Composition containing carbon nanotubes, catalyst for producing carbon nanotubes, and aqueous dispersion of carbon nanotubes
JP2010254546A (en) * 2009-03-31 2010-11-11 Toray Ind Inc Aqueous dispersion of carbon nanotube, electroconductive composite, and method for producing the same
WO2014084042A1 (en) * 2012-11-28 2014-06-05 東レ株式会社 Complex containing double-walled carbon nanotubes
JP2018535131A (en) * 2015-09-14 2018-11-29 リンテック オブ アメリカ インコーポレーテッドＬｉｎｔｅｃ ｏｆ Ａｍｅｒｉｃａ， Ｉｎｃ． Shape-adaptive multi-layer composite
CN112638821A (en) * 2018-09-03 2021-04-09 住友电气工业株式会社 Carbon nanotube composite, method for producing carbon nanotube composite, and method for producing purified carbon nanotube

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5607482B2 (en) * 2010-09-30 2014-10-15 国立大学法人九州大学 Transparent conductive material and method for producing the same
JP2012216284A (en) * 2011-03-31 2012-11-08 Toray Ind Inc Transparent conductor and production method therefor
WO2012177555A2 (en) 2011-06-20 2012-12-27 Yazaki Corporation Cohesive assembly of carbon and its application
JP5831966B2 (en) * 2011-07-08 2015-12-16 国立研究開発法人産業技術総合研究所 Method for producing a carbon nanotube aggregate in which single-walled carbon nanotubes and double-walled carbon nanotubes are mixed at an arbitrary ratio
JP5807455B2 (en) * 2011-08-31 2015-11-10 東レ株式会社 A method for producing a carbon nanotube-containing composition.
KR20130079035A (en) * 2012-01-02 2013-07-10 볼보 컨스트럭션 이큅먼트 에이비 Cover of diesel particulate filter
KR101350690B1 (en) * 2012-02-13 2014-01-14 금호석유화학 주식회사 Highly conductive carbon nanotube having bundle moieties with ultra-low bulk density and its manufacturing method
JP5890241B2 (en) * 2012-04-26 2016-03-22 株式会社カネカ Method for producing graphene laminate
KR101469115B1 (en) 2013-06-17 2014-12-15 수원대학교산학협력단 Plastic material comprising thermoplastic urethane for electrostatic painting
KR101535387B1 (en) * 2013-07-10 2015-07-08 주식회사 엘지화학 Supported catalyst, carbon nanotube agglomerates and method for preparing thereof
JP6492598B2 (en) * 2014-12-04 2019-04-03 日立化成株式会社 Method for producing carbon nanotube
KR101900725B1 (en) * 2016-10-31 2018-09-20 금호석유화학 주식회사 A conductive wire and a method for manufacturing the same
JP6941946B2 (en) * 2017-02-13 2021-09-29 日立造船株式会社 Manufacturing method of carbon nanotube high-density aggregate and carbon nanotube high-density aggregate
JP6806898B2 (en) * 2017-07-06 2021-01-06 富士フイルム株式会社 Conductive film, thermoelectric conversion layer, thermoelectric conversion element, thermoelectric conversion module, method for manufacturing conductive film, composition

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006335604A (en) * 2005-06-02 2006-12-14 Shinshu Univ Sheet of coaxial carbon nanotubes and method for manufacturing the same
JP2008024523A (en) * 2006-07-15 2008-02-07 Toray Ind Inc Method for producing carbon nanotube dispersion and electroconductive material using it
JP2008056523A (en) * 2006-08-30 2008-03-13 Toray Ind Inc Method for producing carbon nanotube
JP2009029695A (en) * 2007-06-29 2009-02-12 Toray Ind Inc Aggregate of carbon nanotubes, dispersion thereof and conductive film

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006335604A (en) * 2005-06-02 2006-12-14 Shinshu Univ Sheet of coaxial carbon nanotubes and method for manufacturing the same
JP2008024523A (en) * 2006-07-15 2008-02-07 Toray Ind Inc Method for producing carbon nanotube dispersion and electroconductive material using it
JP2008056523A (en) * 2006-08-30 2008-03-13 Toray Ind Inc Method for producing carbon nanotube
JP2009029695A (en) * 2007-06-29 2009-02-12 Toray Ind Inc Aggregate of carbon nanotubes, dispersion thereof and conductive film

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010101205A1 (en) * 2009-03-04 2010-09-10 東レ株式会社 Composition containing carbon nanotubes, catalyst for producing carbon nanotubes, and aqueous dispersion of carbon nanotubes
US8992878B2 (en) 2009-03-04 2015-03-31 Toray Industries, Inc. Composition containing carbon nanotubes, catalyst for producing carbon nanotubes, and aqueous dispersion of carbon nanotubes
EP2404873A4 (en) * 2009-03-04 2016-04-06 Toray Industries Composition containing carbon nanotubes, catalyst for producing carbon nanotubes, and aqueous dispersion of carbon nanotubes
JP2010254546A (en) * 2009-03-31 2010-11-11 Toray Ind Inc Aqueous dispersion of carbon nanotube, electroconductive composite, and method for producing the same
WO2014084042A1 (en) * 2012-11-28 2014-06-05 東レ株式会社 Complex containing double-walled carbon nanotubes
JP2018535131A (en) * 2015-09-14 2018-11-29 リンテック オブ アメリカ インコーポレーテッドＬｉｎｔｅｃ ｏｆ Ａｍｅｒｉｃａ， Ｉｎｃ． Shape-adaptive multi-layer composite
CN112638821A (en) * 2018-09-03 2021-04-09 住友电气工业株式会社 Carbon nanotube composite, method for producing carbon nanotube composite, and method for producing purified carbon nanotube

Also Published As

Publication number Publication date
JP2010006663A (en) 2010-01-14

Similar Documents

Publication Publication Date Title
WO2009157529A1 (en) Carbon nanotube assembly and method for producing same
JP4360445B2 (en) Carbon nanotube aggregate and method for producing the same
JP5266907B2 (en) Carbon nanotube aggregate, dispersion and conductive film
JP4325726B2 (en) Carbon nanotube aggregate and conductive film
JP5157301B2 (en) Single- and double-walled carbon nanotube mixed composition
KR101413366B1 (en) Carbon nanotube assembly and electrically conductive film
JP5605373B2 (en) Method for producing carbon nanotube aggregate dispersion
JP5924103B2 (en) Method for producing carbon nanotube dispersion
JP5663855B2 (en) Conductive composite and negative electrode for lithium ion battery.
WO2010101205A1 (en) Composition containing carbon nanotubes, catalyst for producing carbon nanotubes, and aqueous dispersion of carbon nanotubes
JP5194480B2 (en) Carbon nanotube coating film and manufacturing method thereof
WO2016136428A1 (en) Carbon nanotube dispersion and method for manufacturing conductive film
JPWO2014002885A1 (en) Dispersion of carbon nanotube-containing composition and conductive molded body
JP6354583B2 (en) Method for producing aggregate of carbon nanotubes
JP6115372B2 (en) Carbon nanotube aggregate, method for synthesizing carbon nanotube aggregate, resin composition, conductive elastomer composition, and dispersion liquid
JP2009149503A (en) Method for producing carbon nanotube composition
JP2017024964A (en) Carbon nanofiber dispersion liquid, and transparent conductive film and transparent conductive film prepared therewith
JP6398344B2 (en) Carbon nanotube aggregate and method for producing the same
JP6810042B2 (en) Method for producing carbon nanofiber composite, carbon nanofiber composite, method for removing residual catalyst, conductive resin composition, and dispersion liquid, ink or paint

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 09770239

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 09770239

Country of ref document: EP

Kind code of ref document: A1