JP2009007212A - Method for producing carbon nanotube aggregate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a carbon nanotube aggregate so as to produce a carbon nanotube aggregate at low temperature without carrying out secondary working. <P>SOLUTION: The method for producing a carbon nanotube aggregate includes: a first step of firing an organosilicon polymer at 50-400°C in an atmosphere of one or more oxidizing gases selected from air, ozone, oxygen, chlorine gas, bromine gas and ammonia gas to obtain an infusible product of the organosilicon polymer; a second step of firing the infusible product of the organosilicon polymer to obtain silicon carbide; and a third step of firing the silicon carbide at 500-1,700°C in a vacuum having a degree of vacuum of 1.01×10<SP>5</SP>to 1.33×10<SP>-8</SP>Pa under irradiation with laser light of ≤1,100 nm wavelength to obtain an aggregate of carbon nanotubes. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a carbon nanotube aggregate that can produce a carbon nanotube aggregate at a low temperature without secondary processing.

  A carbon nanotube (hereinafter referred to as CNT) has a space in which various substances can be stored, and has different metallic and semiconducting properties depending on the diameter and the difference in the twisting of the graphite sheet on the side of the tube. For this reason, it is regarded as an important substance group in the field of research and development of substances that may develop new functionality.

CNT has a specific surface area exceeds 1000 m ² / g, much larger than the conventional activated carbon. Therefore, a significant improvement in charge capacity is expected by using it as an electrode material for lithium secondary batteries and electric double layer capacitors. In addition, taking advantage of the feature that the tip of CNT is as extremely small as 1 to 10 nm, application to an emitter material of FED (field emission display) is expected. Conventionally proposed field emitters are formed by forming a sharp conical shape for emitting electrons by performing special etching on silicon, or by depositing metal while rotating it obliquely. In such a special formation method, since artificial fine processing is used, it is impossible to make the steep conical tip size 20 to 30 nm or less. The voltage at which electrons can be emitted becomes lower as the tip becomes steeper, but in a conventional 20-30 nm field emitter, a high voltage needs to be applied in order to emit electrons. If CNT is used, there is a possibility that a high-intensity FED driven at a low voltage can be realized.

  However, carbon nanotubes are generally obtained in a bowl-like form, and those subjected to secondary processing including a step of collecting and purifying it are used. For example, CNTs such as bowls are mixed with a binder and processed into a sheet using a sheet forming machine such as a die coater. In such a method, there is a problem that the amount of CNT in a certain volume of the sheet is small, the intended performance cannot be obtained, and the range of use cannot be expanded, for example, the shape that can be processed is limited.

In recent years, as shown in Non-Patent Documents 1 and 2, a technique for depositing CNTs on the surface of silicon carbide single crystal particles has been reported. In this method, SiC, which is a covalently bonded metal carbide, is decomposed by heating the SiC crystal under vacuum, and CNTs are deposited on the surface by removing Si atoms therefrom.

M. Kusunoki, M. Rokkaku and T. Suzuki: Appl. Phys. Lett., 71, pp. 2626 (1997) Kazuyoshi Tanaka; Challenge to carbon nanotube nanodevices, p89-98 (2001)

  However, these methods have a problem that decomposition of the covalently bonded metal carbide requires a high temperature exceeding 2000 ° C. If the decomposition temperature can be lowered, for example, carbon nanotubes can be produced on a silicon substrate that is most widely used in the semiconductor field, and can be widely used for FEDs, high-speed semiconductor switches, and the like.

  Then, an object of this invention is to provide the manufacturing method of the carbon nanotube aggregate for manufacturing a carbon nanotube aggregate at low temperature, without performing secondary processing.

  In order to achieve the above object, the present inventors have conducted extensive research, and as a result, by firing while irradiating silicon with laser light, a carbon nanotube aggregate is produced at a low temperature without secondary processing. I found out that I can do it. That is, the present invention is a method for producing a carbon nanotube aggregate, comprising a step of obtaining a carbon nanotube aggregate by baking silicon carbide while irradiating it with laser light.

  As described above, according to the present invention, it is possible to provide a method for producing a carbon nanotube aggregate for producing a carbon nanotube aggregate at a low temperature without performing secondary processing.

  The carbon nanotube aggregate refers to carbon nanotubes formed on a silicon carbide surface and aggregates thereof. The method for producing a carbon nanotube aggregate according to the present invention is a process for infusible organosilicon polymer to obtain an infusible product. 1 step, a second step of obtaining silicon carbide by firing the infusate of the organosilicon polymer, and a third step of obtaining carbon nanotubes by firing while irradiating the silicon carbide with laser light. It is preferable.

In the method for producing an aggregate of carbon nanotubes according to the present invention, the first step is a step of making an organosilicon polymer infusible to obtain an infusible product. As the organosilicon polymer used in the first step, for example, a polymer whose main chain is composed only of —Si—CH ₂ — structural units, a polymer whose main chain is composed of —Si—CH ₂ —Si—O— structural units, And a polymer whose main chain is composed only of -Si-O- structural units. A mixture containing at least one of these organosilicon polymers can be used.

Main chain -Si-CH 2 _- Examples of the polymer consisting of the structural unit, for example, polysilsesquioxane methylene, polysilsesquioxane ethylene, polysilsesquioxane trimethylene, polysilsesquioxane phenylene, and polycarbosilanes such Porishiruariren like.

Examples of the polymer whose main chain is composed of —Si—CH ₂ —Si—O— structural units include poly (silmethylenesiloxane), poly (ethylenesiloxane), poly (silphenylenesiloxane), and poly (silarylenesiloxane). And poly (silxylylene siloxane).

  Examples of the polymer whose main chain is composed only of —Si—O— structural units include poly (methyleneoxysiloxane), poly (ethyleneoxysiloxane), poly (phenyleneoxysiloxane), and poly (diphenyleneoxysiloxane). Examples include polysilanes.

  The organosilicon polymer may have a metal element having a structural unit of -M-C- (where M is a metal element) or -M-O-. This metal element functions as a catalyst or the like, and can control and promote the form and generation rate of CNT in the third step. It is well known that in the arc discharge method, which is a conventional method for producing CNTs, the presence of a catalyst is very important when synthesizing CNTs. In the case of the arc discharge method, the carbon powder that is a raw material is mixed and reacted with a metal that is a catalyst to control the produced CNT. In the method of manufacturing a carbon nanotube aggregate according to the present invention, the CNT is Since it is formed from silicon carbide, a metal element is included in the organosilicon polymer that is the precursor of silicon carbide.

  The presence position of the metal element may be a crosslinking point in the main chain of the organosilicon polymer. As such a metal element, for example, a rare earth such as iron, cobalt, nickel, molybdenum, titanium, zirconium, rhodium, ruthenium, palladium, platinum, yttrium, or lanthanum / cerium can be used, and these are used in combination. May be. When used in combination such as iron-nickel, cobalt-nickel, ruthenium-palladium, rhodium-palladium, rhodium-platinum, nickel-yttrium, nickel-lanthanum, iron-molybdenum, or cobalt-molybdenum, it is effective in producing CNTs. is there.

  The organosilicon polymer containing the metal element as described above can be obtained, for example, by adding various catalyst compounds containing the metal element that acts as a catalyst in the step of synthesizing the organosilicon polymer. For example, it can be obtained by adding an alkoxide, acetylacetonate, halide, metal complex, carbonyl, or dipiboroylmethanate complex of a metal element such as the rare earth. If the amount is too large, the effect of the catalyst will be saturated, resulting in an increase in cost, which is not preferable. Therefore, the ratio of Si to the metal element (Si: M) in the organosilicon polymer is preferably in the range of 2: 1 to 200: 1, more preferably 20: 1 to 200: 1.

  The shape of the organosilicon polymer used in the present invention is not particularly limited, but it is preferable to use a sheet-like material because it has flexibility in a state of silicon carbide and high versatility. However, when increasing the specific surface area, it may be in the form of a fiber or a woven fabric using it. Since the organosilicon polymer can be easily melted or dissolved in various organic solvents due to its properties, it can be processed into various shapes such as a sheet.

  As a method for forming an organosilicon polymer into a sheet, for example, there is a method in which a substrate is coated with an organosilicon polymer and is peeled from the substrate to form a sheet. In the case of coating, the organosilicon polymer may be used as it is, but may be diluted with an appropriate solvent. As a solvent, what melt | dissolves organosilicon polymers, such as benzene, hexane, ether, tetrahydrofuran, or a dioxane, can be used, for example. As a method of coating the organic silicon polymer on the substrate, a spin coating method, a dip coating method, a screen printing method, a spray coating method, a roll coating method, a meniscus coating method, a bar coating method, or a casting method should be used. Can do.

  When the coating method as described above is performed using a batch method, the substrate needs to be removed when the organosilicon polymer is baked. Therefore, the substrate is soluble in a substance that melts at a low temperature, a highly sublimable substance, or a solvent. It is necessary to use new materials. For example, a plate substrate of a low melting point metal such as tin, zinc or indium, an inorganic crystal soluble in a solvent such as NaCl or KCl, or an organic compound substrate having high sublimation properties such as camphor, paradichlorobenzene or naphthalene Can be used.

  When the coating method as described above is performed using a continuous method, it is necessary to continuously perform infusibility. Therefore, in a low temperature region, a substrate made of resin such as Teflon having good peelability is used. Since heat resistance is required in the high temperature region, a mesh belt furnace in which a thin sheet or mesh such as stainless steel moves can be used.

  As a method of making the organosilicon polymer into a fiber, spinning can be performed by a commonly used synthetic fiber spinning device. An organosilicon polymer having a predetermined composition is prepared to remove substances that are harmful when spinning, such as microgels and impurities. An organosilicon polymer as a raw material is heated and melted and spun at a temperature at which a predetermined viscosity is obtained to produce a raw yarn. The temperature of the organosilicon polymer during spinning varies depending on the composition of the raw material, but a temperature range of 50 to 400 ° C. is preferred. By making it fibrous, the specific surface area can be increased. The organosilicon polymer produced by processing into fibers can be processed into tens to thousands of fiber bundles.

  As a method of making the organosilicon polymer into a woven form, the woven form can be obtained by weaving the above-mentioned fibrous material. The fibrous material can be processed into a plain weave, satin weave, a laminate thereof, or a three-dimensional fabric. Since the woven fabric has a large surface area and good permeability to solutions and gases, it can be suitably used for such purposes. By forming the carbon nanotube aggregate on the surface of the fibrous silicon carbide and then processing the silicon carbide fiber, it is also possible to form a woven fabric composed of silicon carbide fibers having the carbon nanotube aggregate.

  The infusibilization of the organosilicon polymer is performed by infusibilizing at least the surface of the organosilicon polymer in order to prevent the organosilicon polymer from being melted during firing in the second step described later. As a method for infusibilizing the organosilicon polymer, for example, there is a method in which an organosilicon polymer is baked in an oxidizing gas atmosphere to form an infusible oxide film on the surface and infusible. The oxidizing gas is preferably one or more of air, ozone, oxygen, chlorine gas, bromine gas, and ammonia gas. The firing temperature during infusibilization is preferably 50 to 400 ° C. Even if heating is performed at less than 50 ° C., an oxide film cannot be formed on the surface of the organosilicon polymer, and oxidation proceeds excessively at temperatures exceeding 400 ° C. The heating time is suitably in the range of several minutes to 30 hours.

  Other infusibilization methods include a method of irradiating an organosilicon polymer with γ rays or electron beams while heating at low temperature in an oxidizing atmosphere or a non-oxidizing atmosphere. By irradiating γ rays or electron beams, the organosilicon polymer can be polymerized and infusible. The method by γ-ray or electron beam irradiation can infusibilize a low-melting point organosilicon polymer that cannot be obtained by a method of baking in an oxidizing gas atmosphere. The organosilicon polymer may have a melting point of 50 ° C. or lower depending on its composition. Even in such a case, if it is γ-ray or electron beam irradiation, it is not necessary to make it a high temperature state, so that infusibilization can be performed without melting the organosilicon polymer.

  The second step according to the present invention is a step of obtaining silicon carbide by firing the infusate of the organosilicon polymer, and is performed at 500 to 2000 ° C., preferably 800 in a vacuum, inert gas or reducing gas atmosphere. The infusible product of the organosilicon polymer is preferably baked in a temperature range of ˜1500 ° C. By firing, silicon carbide can be obtained. Generally, an infusibilized product of an organosilicon polymer releases a readily volatile component at 500 to 700 ° C. by a thermal polymerization reaction and a thermal decomposition reaction. Mineralization becomes intense from 700 ° C., mineralization can be almost completed at about 800 ° C., and silicon carbide can be generated. Furthermore, if necessary, the crystallinity can be improved by firing in the range of 800 to 2000 ° C. The infusibilized product can be fired under tension or under no tension.

  The third step according to the present invention is a step of firing while irradiating the silicon carbide with laser light. In the third step, the laser beam acts selectively on the chemical bond of the substance in a short time, and the reaction (firing) temperature can be lowered. The wavelength of the laser light is preferably 1100 nm or less. As the laser beam used in the present invention, the shorter the wavelength, the better. However, when the wavelength is too short, the laser beam is absorbed by gas or the like, and the utilization efficiency of laser energy is lowered. Therefore, it is more preferably 300 nm to 100 nm. Light having a short wavelength has a strong action and is effective in reducing the reaction temperature. Such lasers include a ruby laser, a glass laser, a YAG laser, a semiconductor laser such as GaAs and InGaAsP, a dye laser, a He—Ne laser, an argon laser, and an excimer laser. Among these, an argon laser or an excimer laser, particularly an excimer laser, having a short wavelength and a large effect on chemical bonding is preferable.

In the third step, CNTs are produced by removing silicon in silicon carbide by applying laser light to chemical bonds. It is considered that silicon is removed as silicon monoxide by combining with oxygen contained in silicon carbide by irradiation with laser light. And it is thought that CNT produces | generates from the carbon which the silicon carbide surface from which silicon was removed remained. Therefore, CNT production can be controlled by controlling the vapor pressure of silicon monoxide. When the degree of vacuum is low, it is necessary to increase the vapor pressure of silicon monoxide, and thus it is necessary to increase the temperature. On the other hand, when the degree of vacuum is high, the vapor pressure becomes high, so the temperature may be low, but considering the CNT generation rate, the temperature is preferably high. Therefore, in the third step according to the present invention, firing is preferably performed in a vacuum, and the degree of vacuum is preferably in the range of 1.01 × 10 ^{5 to} 1.33 × 10 ⁻⁸ Pa. A range of 33 × 10 ^{−1 to} 1.33 × 10 ⁻⁸ Pa is more preferable. The firing temperature is preferably in the range of 500 to 1700 ° C, more preferably in the range of 500 to 1500 ° C, and still more preferably in the range of 500 to 1000 ° C.

  FIG. 1 shows a conceptual diagram of an apparatus for irradiating a wide area of silicon carbide with laser light. This apparatus includes a vacuum vessel 12 in which a silicon carbide sheet 10 irradiated with laser light is accommodated, and a laser oscillator 14. The silicon carbide sheet 10 is installed so as to be movable in the longitudinal direction (y direction in FIG. 1) by being wound up by the rotation of the roller 16, and the silicon carbide sheet 10 is placed on the back side of the silicon carbide sheet 10. A heater 18 that can be heated is provided. Between the laser oscillator 14 and the vacuum vessel 12, an irradiation unit 20 composed of a laser transmission window is installed, and the laser light 22 oscillated from the laser oscillator 14 is shaped by a pair of lenses (not shown). The silicon carbide sheet 10 is irradiated through the irradiation unit 20. By changing the angle of the irradiation unit 20 in the width direction, the irradiation position of the laser beam 22 on the silicon carbide sheet 10 can be moved in the width direction (x direction in FIG. 1). Therefore, by moving the silicon carbide sheet 10 in the vertical direction and changing the angle in the width direction of the irradiation unit 20, the laser beam is irradiated over a wide area of the silicon carbide sheet 10, and the carbon nanotube aggregate is formed. Can be generated. In addition, you may comprise so that a laser beam may be irradiated also from the back surface side of the silicon carbide sheet 10. FIG.

  In the method for producing an aggregate of carbon nanotubes according to the present invention, the aggregate of carbon nanotubes can be formed on the surface of silicon carbide by firing while irradiating the surface of silicon carbide with laser light. The height of the aggregate of carbon nanotubes formed on the surface of silicon carbide, that is, the thickness of the CNT layer, the type and concentration of metal elements in silicon carbide, the degree of vacuum during firing, the firing temperature, the firing time, the oxygen in the atmosphere It can be controlled to an arbitrary thickness by adjusting the concentration, the wavelength of the laser, the energy density, the irradiation time, and the like.

  The thickness of the CNT layer can be selected depending on the purpose. When the tip of CNT is important like FED, the effect of FED can be exhibited at about 10 nm. On the other hand, when the charge capacity is proportional to the volume of the electrode material, such as a capacitor, the CNT layer is preferably thick. However, when the thickness increases, CNTs may be peeled off from the silicon carbide surface. Therefore, the thickness of the CNT layer is preferably 10 nm to 1000 nm.

  According to the method for producing a carbon nanotube aggregate of the present invention, for example, a silicon carbide sheet 30 as shown in FIG. 2 can be obtained. In this silicon carbide sheet 30, as shown in FIG. 3, the AA cross section is simply shown, and a carbon nanotube aggregate 31 is directly formed on the surface of the sheet-like silicon carbide 30. Further, as shown in FIG. 4, the carbon nanotube aggregate 33 can be obtained directly on the surface of the fibrous silicon carbide 34, and the fibrous silicon carbide 34 having the carbon nanotube aggregate 33 can be formed into a woven shape. it can.

  According to the method for producing an aggregate of carbon nanotubes of the present invention, since CNTs are directly formed on the silicon carbide surface, compared with the case where secondary processing such as collecting and attaching the cocoon-like CNTs to a sheet-like material is required. The amount of CNT per unit area can be increased, and application to various fields utilizing the properties of CNT is possible. Further, by firing the silicon carbide while irradiating it with laser light, a carbon nanotube aggregate can be produced at a lower temperature than in the case of firing alone. Since it becomes possible to manufacture at a lower temperature than before, it becomes possible to apply CNTs to industrial fields that have been difficult until now. For example, what used to be a reaction using soda glass as a substrate can be reacted on a plastic substrate. Therefore, the method for producing an aggregate of carbon nanotubes of the present invention is extremely useful in a wide range of fields such as the electronics field and the energy field.

  Next, examples of the method for producing a carbon nanotube aggregate according to the present invention will be described.

(Reference example)
First, polycarbosilane which is an organosilicon polymer used as a raw material compound was produced as a reference example. That is, 2.5 liters of anhydrous xylene and 400 g of sodium were placed in a 5 liter three-necked flask, heated to the boiling point of xylene under a nitrogen gas stream, and 1 liter of dimethyldichlorosilane was added dropwise over 1 hour. After completion of the dropwise addition, the mixture was refluxed for 10 hours to form a precipitate. The precipitate was filtered, washed first with methanol and then with water to obtain 420 g of white powder of polydimethylsilane.

  On the other hand, by heating 759 g of diphenyldichlorosilane and 124 g of boric acid in a nitrogen gas atmosphere in n-butyl ether at a temperature of 100 to 120 ° C., the resulting white resin is further heated in vacuum at 400 ° C. for 1 hour. 530 g of polyborodiphenylsiloxane was obtained.

  Next, 8.27 g of the above polyborodiphenylsiloxane was added to and mixed with 250 g of the above polydimethylsilane, heated in a 2 liter quartz tube equipped with a reflux tube to 350 ° C. under a nitrogen stream, and polymerized for 6 hours. Polycarbosilane which is a raw material organosilicon polymer was obtained.

  40 g of the above polycarbosilane and 32.3 g of bis-acetylacetonate platinum were collected, and 400 ml of xylene was added to this mixture to form a mixed solution consisting of a uniform phase, and stirred at 130 ° C. for 1 hour under a nitrogen gas atmosphere. A reflux reaction was performed. After completion of the reflux reaction, the temperature was further raised to 230 ° C. to distill the solvent xylene, followed by polymerization at 230 ° C. for 1 hour to obtain platinum-containing polycarbosilane, which is an organosilicon polymer containing platinum. Si: Pt in this polymer was about 8: 1.

Example 1
1 g of platinum-containing polycarbosilane obtained as a reference example was dissolved in 10 g of xylene, and this solution was applied on a 10 mm × 10 mm × 5 mmt NaCl substrate. This was heated from room temperature to 7.5 ° C./hour in air and kept at 175 ° C. for 2 hours to be infusible. In order to peel off the infusible sheet, the substrate was removed by dissolving in water. The obtained infusibilized sheet was heated up to 800 ° C. in a nitrogen stream in 12 hours, and held at 800 ° C. for 1 hour and fired. The thickness of the obtained sheet was 30 μm. The sheet according to Example 1 was subjected to heat treatment at 800 ° C. for 2 hours while irradiating an ArF excimer laser (oscillation wavelength: 193 nm) at 1000 mJ / cm ² at a vacuum degree of 1 × 10 ⁻³ Torr. A nanotube aggregate was obtained. The appearance was black and no significant change was observed before and after treatment. The thickness of the produced CNT layer was about 100 nm.

(Example 2)
1 g of platinum-containing polycarbosilane obtained as a reference example was dissolved in 10 g of xylene, and this solution was applied on a 10 mm × 10 mm × 5 mmt NaCl substrate. This was heated from room temperature to 7.5 ° C./hour in air and kept at 175 ° C. for 2 hours to be infusible. In order to peel off the infusible sheet, the substrate was removed by dissolving in water. The obtained infusibilized sheet was heated up to 800 ° C. in a nitrogen stream in 12 hours, and held at 800 ° C. for 1 hour and fired. The thickness of the obtained sheet was 30 μm. The sheet according to Example 2 was subjected to heat treatment at 1000 ° C. for 2 hours while irradiating an ArF excimer laser (oscillation wavelength: 193 nm) at 1000 mJ / cm ² at a vacuum degree of 1 × 10 ⁻³ Torr. A nanotube aggregate was obtained. The appearance was black and no significant change was observed before and after treatment. The thickness of the generated CNT layer was about 150 nm.

(Example 3)
1 g of platinum-containing polycarbosilane obtained as a reference example was dissolved in 10 g of xylene, and this solution was applied on a 10 mm × 10 mm × 5 mmt NaCl substrate. This was heated from room temperature to 7.5 ° C./hour in air and kept at 175 ° C. for 2 hours to be infusible. In order to peel off the infusible sheet, the substrate was removed by dissolving in water. The obtained infusibilized sheet was heated up to 800 ° C. in a nitrogen stream in 12 hours, and held at 800 ° C. for 1 hour and fired. The thickness of the obtained sheet was 30 μm. The sheet according to Example 3 was subjected to a heat treatment at 800 ° C. for 2 hours while irradiating the sheet with a KrF excimer laser (oscillation wavelength: 248 nm) at 1000 mJ / cm ² at a vacuum degree of 1 × 10 ⁻³ Torr. A nanotube aggregate was obtained. The appearance was black and no significant change was observed before and after treatment. The thickness of the generated CNT layer was about 70 nm.

(Comparative Example 1)
1 g of platinum-containing polycarbosilane obtained as a reference example was dissolved in 10 g of xylene, and this solution was applied on a 10 mm × 10 mm × 5 mmt NaCl substrate. This was heated from room temperature to 7.5 ° C./hour in air and kept at 175 ° C. for 2 hours to be infusible. In order to peel off the infusible sheet, the substrate was removed by dissolving in water. The obtained infusibilized sheet was heated up to 1200 ° C. in 12 hours in a nitrogen stream, and held at 1200 ° C. for 1 hour and baked. The thickness of the obtained sheet was 30 μm. The sheet in vacuum 1 × ¹⁰ -3 Torr, were subjected to 2 hours of heat treatment at 1000 ° C. CNT was not produced.

It is a conceptual diagram of the apparatus in the case of irradiating a wide area of silicon carbide with a laser beam. It is a top view of a silicon carbide sheet. It is AA sectional drawing of FIG. It is a top view of the fibrous silicon carbide made into the fabric form.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Silicon carbide sheet 12 Vacuum container 14 Laser oscillator 16 Roller 18 Heater 20 Irradiation part 22 Laser light 30 Silicon carbide sheet 31 Carbon nanotube aggregate 32 Sheet-like silicon carbide 33 Carbon nanotube aggregate 34 Fibrous silicon carbide

Claims (8)

  A method for producing a carbon nanotube aggregate, comprising a step of obtaining a carbon nanotube aggregate by firing silicon carbide while irradiating it with laser light. A first step of infusible organosilicon polymer to obtain an infusible product,
A second step of obtaining silicon carbide by firing the infusible product of the organosilicon polymer;
And a third step of obtaining the carbon nanotube aggregate by firing the silicon carbide while irradiating the silicon carbide with laser light.   The method for producing a carbon nanotube aggregate according to claim 2, wherein the organosilicon polymer is in the form of a sheet, a fiber, or a fabric.   In the first step, the organosilicon polymer is baked at a temperature of 50 to 400 ° C. in an oxidizing gas atmosphere of one or more of air, ozone, oxygen, chlorine gas, bromine gas, and ammonia gas. The method for producing a carbon nanotube aggregate according to claim 2 or 3, wherein the carbon nanotube aggregate is melted.   5. The second step is characterized in that the infusibilized product of the organosilicon polymer is baked at a temperature of 500 to 2000 ° C. in a vacuum, an inert gas atmosphere or a reducing gas atmosphere. The manufacturing method of the carbon nanotube aggregate of description. The step according to claim 1 or the third step is characterized in that the silicon carbide is fired at a temperature of 500 to 1700 ° C. in a degree of vacuum of 1.01 × 10 ^{5 to} 1.33 × 10 ⁻⁸ Pa. The manufacturing method of the carbon nanotube aggregate in any one of Claims 1 thru | or 5.   The method of manufacturing a carbon nanotube aggregate according to any one of claims 1 to 6, wherein the step of claim 1 or the third step has a wavelength of laser light of 1100 nm or less.   8. The method for producing a carbon nanotube aggregate according to claim 1, wherein in the step according to claim 1 or the third step, the laser beam is an excimer laser.

Images