Method and apparatus for producing carbon nanotubes

Abstract

[Problem] To provide a carbon nanotube manufacturing method and manufacturing device capable of manufacturing a carbon nanotube with a high yield. [Solution] A first manufacturing device 100 primarily comprises a mass flow controller 110, a growth furnace 120, a quartz tube 130, a pressure gauge 150, an electromagnetic valve 160, a pressure adjustment valve 170, and a needle valve 180. The quartz tube 130 is a cylindrical tube comprising quartz, and is inserted into the growth furnace 120. The interior of the growth furnace 120 can be adjusted to a temperature suitable for the thermal decomposition temperature of each raw material resin. The pressure gauge 150 is connected to an outlet pipe 104 extending from an outlet end of the quartz tube 130. The electromagnetic valve 160 receives a pressure value from the pressure gauge 150, and opens / closes a pipe 106 in accordance with the pressure value. The raw material resin 144 is installed near an inlet end of the growth furnace 120. A catalyst metal 142 is installed at a position separated by a prescribed distance from the inlet end of the growth furnace 120.

Description

【Technical Field】 【0001】 The present invention relates to a method and an apparatus for manufacturing carbon nanotubes. 【Background Art】 【0002】 There is known a method for manufacturing carbon nanotubes in which a metal-containing nanofiber formed by mixing a nanofiber made of an organic polymer and a catalytic metal is placed in a heat-generating container, and electromagnetic wave energy is irradiated onto the heat-generating container to cause the heat-generating container to generate heat, thereby heating the metal-containing nanofiber. As a result, carbon nanotubes containing the metal are generated using the nanofiber as a carbon source. The metal-containing nanofibers include those in which the surface of the nanofiber is coated with a metal and those in which metal nanoparticles are encapsulated in the nanofiber. The metal-containing nanofiber having a metal coated on the surface of the nanofiber is manufactured by coating the nanofiber with a metal by a general metal coating method, such as vacuum evaporation. The metal-containing nanofiber in which metal nanoparticles are encapsulated in the nanofiber is manufactured by an electrospinning method using, as a raw material, a suspension containing metal nanoparticles and the material resin of the nanofiber, for example, a suspension in which metal nanoparticles are dispersed in a solution obtained by dissolving the material resin of the nanofiber in a solvent. The yield of the carbon nanotubes was about 4% (Patent Document 1). 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2010-269996 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 However, when the yield of the carbon nanotubes is as low as about 4% in this way, the manufacturing cost per unit time and per unit mass of the obtained carbon nanotubes increases. 【0005】 The present invention has been made in view of the above problems, and an object thereof is to provide a method and an apparatus for manufacturing carbon nanotubes capable of manufacturing carbon nanotubes in a high yield. 【Means for Solving the Problems】 【0006】 The method for manufacturing carbon nanotubes according to the first invention of the present application includes a raw material vaporization step of vaporizing a resin to obtain a carbon-containing gas, a catalyst sublimation step of sublimating a catalyst metal to obtain a catalyst gas, a contact step of bringing the catalyst gas into contact with the carbon-containing gas, and a control step of maintaining the pressure in the space where the carbon-containing gas and the catalyst gas are present within a predetermined range. 【0007】 It is preferable to further include a morphological change step of thermally decomposing the catalyst gas to cause a morphological change into catalyst metal fine particles. 【0008】 In the contact step, it is preferable to grow carbon nanotubes by chemical vapor deposition. 【0009】 In the raw material vaporization step, the resin is vaporized in a raw material vaporization unit, in the catalyst sublimation step, the catalyst metal is sublimated in a catalyst sublimation unit, the space is a growth unit, and in the control step, it is preferable to introduce a carrier gas into the raw material vaporization unit, the catalyst sublimation unit, and the growth unit and maintain the pressure in the growth unit within a predetermined range. 【0010】 In the raw material vaporization step, it is preferable to heat the resin at a temperature corresponding to the resin, and in the catalyst sublimation step, it is preferable to heat and sublime the catalyst metal at a temperature corresponding to the catalyst metal. 【0011】 In the contact step, it is preferable to heat the wall surface forming the space to a predetermined temperature, and the carbon nanotubes grow on the wall surface. 【0012】 In the contact growth step, it is preferable to heat the substrate installed in the space to a predetermined temperature, and the carbon nanotubes grow on the substrate. 【0013】 The catalyst metal is preferably an organometallic molecule containing Fe, Ni, Co, or combinations thereof. 【0014】 The raw material resin is preferably polyethylene (PE), polypropylene (PP), acrylonitrile butadiene styrene (ABS), polystyrene (PS), polylactic acid (PLA), polycarbonate (PC), polyimide (PI), polyethylene terephthalate (PET), polyvinyl chloride (PVC), or any combination thereof. 【0015】 The carbon nanotubes are multilayered, and it is preferable that carbon nanotubes are grown in an amount of 1% to 81% by mass of the resin. 【0016】 The carbon nanotube manufacturing apparatus according to the second invention of this application comprises a raw material vaporization section that vaporizes a resin to obtain a carbon-containing gas, a catalyst sublimation section that sublimes a catalyst metal to obtain a catalyst gas, a growth section that brings the catalyst gas and the carbon-containing gas into contact, and a control section that maintains the pressure within the growth section within a predetermined range. 【0017】 In the growth section, it is preferable to thermally decompose the catalyst gas and change its shape into catalyst metal nanoparticles. 【0018】 It is preferable to grow carbon nanotubes in the growth section using chemical vapor deposition. 【0019】 The control unit preferably introduces a carrier gas into the raw material vaporization section, the catalyst sublimation section, and the growth section, and maintains the pressure within the growth section within a predetermined range. 【0020】 The growth section is preferably located downstream of the raw material vaporization section and the catalyst sublimation section. 【0021】 The control unit preferably includes a pressure sensor for detecting the internal pressure of the growth section and a valve for adjusting the internal pressure of the growth section. 【0022】 The contact step involves heating the wall surface that forms the growth area to a predetermined temperature, and it is preferable that the carbon nanotubes grow on the wall surface. 【0023】 The contact step preferably involves heating the substrate placed within the growth section to a predetermined temperature, allowing the carbon nanotubes to grow on the substrate. 【0024】 The catalyst metal is preferably an organometallic molecule containing Fe, Ni, Co, or combinations thereof. 【0025】 The resin is preferably polyethylene (PE), polypropylene (PP), acrylonitrile butadiene styrene (ABS), polystyrene (PS), polylactic acid (PLA), polycarbonate (PC), polyimide (PI), polyethylene terephthalate (PET), polyvinyl chloride (PVC), or any combination thereof. 【0026】 The carbon nanotubes are multilayered, and it is preferable that carbon nanotubes are grown in an amount of 1% to 81% by mass of the resin. [Effects of the Invention] 【0027】 The present invention provides a method and apparatus for producing carbon nanotubes that can produce carbon nanotubes in high yield. [Brief explanation of the drawing] 【0028】 [Figure 1] This is a schematic diagram of a first manufacturing apparatus according to a first embodiment of the present invention. [Figure 2] This graph shows the FTIR spectrum of a carbon-containing gas. [Figure 3] This graph shows the FTIR spectrum of a carbon-containing gas. [Figure 4] This graph shows the FTIR spectrum of a carbon-containing gas. [Figure 5] This graph shows the FTIR spectrum of a carbon-containing gas. [Figure 6] This graph shows the growth rate of carbon nanotubes. [Figure 7] This is an electron microscope image of the generated carbon nanotubes. [Figure 8] This graph shows the Raman spectrum of the generated carbon nanotubes. [Figure 9] This graph shows the Ig / Id ratio of the generated carbon nanotubes. [Figure 10] This is a schematic diagram of the second manufacturing apparatus according to the second embodiment. [Figure 11] This is a schematic diagram of the third manufacturing apparatus according to the third embodiment. [Figure 12] This is a schematic diagram of the fourth manufacturing apparatus according to the fourth embodiment. [Figure 13] This is an electron microscope image of the generated carbon nanotubes. [Figure 14] This is an electron microscope image of the generated carbon nanotubes. [Modes for carrying out the invention] 【0029】 The first manufacturing apparatus 100 and manufacturing method according to the first embodiment of the present invention will be described below with reference to Figures 1 to 9. 【0030】 Referring to Figure 1, the first manufacturing apparatus 100 mainly comprises a mass flow controller 110, a growth furnace (growth section) 120, a quartz tube 130, a pressure gauge 150, a solenoid valve 160, a pressure regulating valve 170, and a needle valve 180. 【0031】 The mass flow controller 110 delivers carrier gas to the quartz tube 130 at a desired flow rate via the inlet pipe 102. As the carrier gas, for example, a mixed gas of argon / hydrogen (Ar / H2) or pure argon gas can be used. 【0032】 The growth furnace 120 is capable of adjusting the internal temperature to any desired temperature, for example, from 500°C to 900°C. As an example, a product named ARF-30K manufactured by Asahi Rika Seisakusho is used. 【0033】 The quartz tube 130 is a cylindrical tube made of quartz, with an outer diameter of 40 mm, an inner diameter of 36 mm, a radial thickness of 2 mm, and a length of 570 mm, and is inserted into the growth furnace 120. The inlet and outlet ends of the quartz tube 130 protrude from the inlet and outlet ends of the growth furnace 120 by a predetermined length. In this specification, the interior of the quartz tube 130 located inside the growth furnace 120 is also referred to as the interior of the growth furnace 120. 【0034】 The pressure gauge 150 is connected to an outlet pipe 104 extending from the outlet end of the quartz tube 130. It measures the pressure inside the quartz tube 130, preferably in the region where carbon nanotubes grow, and transmits the pressure value to the solenoid valve 160. After being connected to the pressure gauge 150, the outlet pipe 104 branches into two directions: one pipe 106 is connected to the solenoid valve 160, and the other pipe 107 is connected to the needle valve 180. The pressure gauge 150 measures the pressure at the connection point with the outlet pipe 104. This point is connected to the inside of the quartz tube 130, particularly the region where carbon nanotubes grow, without passing through a structure that causes the pressure to fluctuate. Therefore, the pressure at this point is approximately the same as the pressure inside the quartz tube 130 and in the region where carbon nanotubes grow. 【0035】 The solenoid valve 160 receives a pressure value from the pressure gauge 150 and opens and closes the piping 106 according to the pressure value. In the piping 106, a pressure regulating valve 170 is connected to the outlet side of the solenoid valve 160. 【0036】 The pressure regulating valve 170 and the needle valve 180 can be opened and closed at will by the user. The outlet sides of the pressure regulating valve 170 and the needle valve 180 are exhausted through the exhaust pipe 108. Negative pressure is applied to the exhaust pipe 108 from an externally installed negative pressure generating unit, such as a negative pressure pump. The pressure gauge 150, the solenoid valve 160, the pressure regulating valve 170, and the needle valve 180 constitute the control unit. 【0037】 The substrate 146 is a solid, for example, made of silicon, and is placed in the longitudinal center of the quartz tube 130. 【0038】 The raw material resin 144 is a solid containing carbon atoms and consists of, for example, polyethylene (PE), polypropylene (PP), acrylonitrile butadiene styrene (ABS), polystyrene (PS), polylactic acid (PLA), polycarbonate (PC), polyimide (PI), polyethylene terephthalate (PET), polyvinyl chloride (PVC), or mixtures thereof. It is placed near the inlet end of the growth furnace 120, that is, in a position within the quartz tube 130 such that it protrudes slightly from the inlet end of the growth furnace 120. The distance that the raw material resin 144 protrudes from the inlet end of the growth furnace 120 is about 8 mm and is determined according to the type of raw material resin 144. In this embodiment, a part of the quartz tube 130 that is part of the growth furnace 120 and is located in a position where it can receive enough heat from the growth furnace 120 to vaporize the raw material resin 144 forms the raw material vaporization section 132. When the raw material resin 144 is polyethylene (PE), polypropylene (PP), acrylonitrile butadiene styrene (ABS), polystyrene (PS), polylactic acid (PLA), polyethylene terephthalate (PET), or polyvinyl chloride (PVC), the raw material vaporization section 132 is provided in a portion where the thermal decomposition temperature is 400°C. When the raw material resin is polycarbonate (PC) or polyimide (PI), the raw material vaporization section 132 is provided in a portion where the thermal decomposition temperature is 800°C. The above thermal decomposition temperatures are examples only, and are not limited to the above temperatures, but may be, for example, 200°C to 900°C, 200°C to 300°C, 300°C to 500°C, or 500°C to 900°C. The temperature at which carbon nanotubes can grow is, for example, 800°C. 【0039】 The catalyst metal 142 is a solid containing an organometallic compound, for example, ferrocene, and is installed in the quartz tube 130 at a predetermined distance from the inlet end of the growth furnace 120. The ferrocene is preferably Fujifilm Wako Pure Chemical Industries product no. 068-05982. The distance from the catalyst metal 142 to the inlet end of the growth furnace 120 is such that the catalyst metal 142 can receive enough heat from the growth furnace 120 to sublimate, and is approximately 25 mm when the catalyst metal 142 is ferrocene. In this embodiment, the portion of the quartz tube 130 outside the growth furnace 120, at a distance from the inlet end of the growth furnace 120 such that the catalyst metal 142 can receive enough heat from the growth furnace 120 to sublimate, constitutes the catalyst sublimation section 134. 【0040】 Next, a process for producing carbon nanotubes, including one embodiment of the present invention, will be described. Throughout this process, negative pressure is applied to the exhaust pipe 108. 【0041】 First, a substrate 146 is placed in the longitudinal center of the quartz tube 130, a raw material resin 144 is placed in the raw material vaporization section 132, and a catalyst metal 142 is placed in the catalyst sublimation section 134. 【0042】 Next, a vacuuming process is performed. In this process, the flow rate of the mass flow controller 110 is set to 0 sccm, the pressure regulating valve 170 and the needle valve 180 are opened, and the solenoid valve 160 is closed. As a result, gas is drawn out of the quartz tube 130 via the exhaust pipe 108, and the pressure inside the quartz tube 130 decreases. The solenoid valve 160 is then set to automatically open when the pressure value from the pressure gauge 150 is -15 kPa or higher relative to atmospheric pressure, and to automatically close when it is -20 kPa or lower relative to atmospheric pressure. 【0043】 Next, the gas introduction and heating process is performed. In this process, the flow rate in the mass flow controller 110 is set to 300 sccm, the pressure regulating valve 170 is opened, and the solenoid valve 160 is closed. Then, the needle valve 180 is adjusted to adjust the pressure inside the quartz tube 130 to -20 kPa. As a result, the carrier gas Ar / H2 is introduced into the quartz tube 130, and the solenoid valve 160 is kept closed. The concentration of the carrier gas Ar / H2 inside the quartz tube 130 is approximately 3%. Then, the growth furnace 120 raises the temperature inside the furnace. Since the raw material vaporization section 132 and the catalyst sublimation section 134 are located in the aforementioned places, they receive heat from the growth furnace 120, causing the raw material resin 144 to vaporize into a carbon-containing gas and the catalyst metal 142 to sublimate into a catalyst gas. 【0044】 Next, a growth process is performed. In this process, the needle valve 180 is maintained at the position adjusted during the gas introduction and heating process, and the pressure adjustment valve 170 is kept open. As the temperature inside the quartz tube 130 rises due to the heating of the growth furnace 120, the raw material resin 144 is thermally decomposed and becomes a carbon-containing gas (raw material vaporization step). At this time, the catalyst metal 142 sublimes (catalytic sublimation step) and becomes catalyst metal nanoparticles in the space of the quartz tube 130 and on the inner wall of the quartz tube 130 and the surface of the substrate 146 (morphological change step). These carbon-containing gases and catalyst metal nanoparticles react to grow carbon nanotubes (contact step). If only the carbon-containing gas comes into contact with the inner wall of the quartz tube 130 and the substrate 146 in an environment where catalyst metal nanoparticles are absent, amorphous carbon will grow, hindering the formation of carbon nanotubes. Therefore, catalyst metal nanoparticles are formed on the inner wall of the quartz tube 130 and / or on the surface of the substrate 146 simultaneously with and / or before the carbon-containing gas. Here, "simultaneous" includes not only the exact same moment, but also the time from 0 to approximately 240 seconds from when the catalyst gas comes into contact with the inner wall of the quartz tube 130 and the substrate 146 until the carbon-containing gas comes into contact with the inner wall of the quartz tube 130 and the substrate 146. As the raw material resin 144 and catalyst metal 142 vaporize and sublimate, the pressure inside the quartz tube 130 increases. As mentioned above, the electromagnetic valve 160 is set to automatically open when the pressure value from the pressure gauge 150 is -15kPa or higher relative to atmospheric pressure, and to automatically close when it is -20kPa or lower relative to atmospheric pressure. Therefore, when the pressure value measured by the pressure gauge 150 is -15kPa or higher, the electromagnetic valve 160 automatically opens and lowers the pressure inside the quartz tube 130. Then, when the pressure inside the quartz tube 130 drops to -20kPa or lower, the electromagnetic valve 160 automatically closes. In this way, the pressure inside the quartz tube 130 is maintained within the range of -15 to -20kPa. In this embodiment, a state in which the pressure inside the quartz tube 130 is in the range of -15 to -20 kPa is considered to be a state in which the pressure inside the quartz tube 130 is kept constant. When solids such as the catalyst metal 142 and raw material resin 144 are vaporized and sublimated, the pressure inside the quartz tube 130, that is, the closed space, increases. This creates a risk of the quartz tube 130 rupturing, but according to this embodiment, since the pressure inside the quartz tube 130 is kept constant, there is no risk of the quartz tube 130 rupturing.In addition, if the pressure inside the quartz tube 130 increases, the amount of sublimation and vaporization of the catalyst gas and carbon-containing gas may decrease due to the saturated vapor pressure. On the other hand, if the pressure inside the quartz tube 130 is lowered too much, the amount of sublimation and vaporization of the catalyst gas and carbon-containing gas may increase too much due to the saturated vapor pressure. However, according to this embodiment, by keeping the pressure inside the quartz tube 130 constant, the catalyst gas and carbon-containing gas can be generated at a constant sublimation and vaporization rate, thereby enabling the production of high-quality carbon nanotubes. When producing carbon nanotubes using only gases such as pre-prepared catalyst gas and / or carbon-containing gas, it is conceivable to adjust the pressure inside the furnace and the amount of catalyst gas and / or carbon-containing gas by controlling the inflow rate of catalyst gas and / or carbon-containing gas. However, in this embodiment, since solids are used as catalyst and / or raw materials, the pressure inside the furnace and the amount of catalyst gas and / or carbon-containing gas are adjusted by directly controlling the pressure inside the quartz tube 130. By performing this growth process for a predetermined period, carbon nanotubes are formed on the inner wall of the quartz tube 130 and on the substrate 146. 【0045】 When carbon nanotube production is to be terminated, the heating by the growth furnace 120 is stopped, simultaneously cutting off the supply of carbon-containing gas and catalyst gas. This allows for the production of carbon nanotubes only, without the generation of amorphous carbon. 【0046】 Next, the FTIR spectra of carbon-containing gases will be described using FIGS. 2 to 5. As the raw material resin 144, for PE, the experimental resin #11026 (low-density PE) manufactured by Sampratech was used, for PP, the resin plate #PPN-050503 manufactured by AS ONE was used, for ABS, the 3D printer filament manufactured by Pxmalion was used, for PS, #PS2035-1 manufactured by Hikari was used, for PLA, the 3D printer filament manufactured by Pxmalion was used, for PET, a commercially available transparent PET bottle was used, for PI, the polyimide film #3-1966-02 (thickness 25 μm, 100H) manufactured by AS ONE was used, and for PC, #KPAC301-1 manufactured by Hikari was used. As the carrier gas, the Ar / H2 (3%) gas manufactured by Yokkaichi Shokai was used. Then, for PE, PP, ABS, PS, PLA, and PET, the temperature was raised to 400 °C, and for PI and PC, the temperature was raised to 800 °C, and the FTIR spectra were measured using the industrial gas analyzer IG-1000 manufactured by Otsuka Electronics Co., Ltd. 【0047】 FIG. 2 shows the spectra of each carbon-containing gas in the region from a wavenumber of 600 cm to 4500 cm -1 . For PE, PP, ABS, PC, PLA, and PS, that is, for those other than PI and PET, peaks of CH2 and CH3 derived from alkanes were observed in the band at a wavenumber of approximately 2900 cm -1 . For ABS, PI, PC, and PS, peaks of C-C bonds derived from aromatic rings were observed in the band from a wavenumber of approximately 1500 cm [[ID=​​​​​​​​​​​​​​​​It appears in the band, with a peak at 2932 cm² at the site of the alkyl chain, attributed to CH3. -1 , 2967cm -1 The peaks appeared in the bands. In particular, clear peaks were observed at all of these wavenumbers for PE, PP, ABS, and PS. Since both CH2 and CH3 peaks were observed for PE and PP, it is thought that PE and PP were decomposed into monomers such as ethane, propane, and butane, which are terminated with CH3. Here, it is thought that CH3 was generated in PE, which does not originally contain CH3, when the dangling bond was terminated by protons generated during thermal decomposition. For ABS, a peak attributable to CH2 was confirmed, and the intensity of the CH3 peak was low. The reason why a peak attributable to CH2 was confirmed for ABS is thought to be because ABS is composed of acrylonitrile (C3H3N), butadiene (CH2=CH-CH=CH2), and styrene (C8H8), and these molecules have CH2 at their ends. For PS, a large CH2 peak was also observed, similar to ABS, but the intensity of CH3 relative to CH2 was higher than in ABS. From PET, slight CH2 and CH3 peaks were observed, but the overall intensity was low. No peaks appeared in this region for PI and PLA. 【0049】 Using Figure 4, the wavenumber 1000 cm in Figure 2 -1 From 1900cm -1 The spectra of each carbon-containing gas in the region are shown. Wavenumber 1000 cm⁻¹ -1 From 1900cm -1 It is known that peaks appear in this region due to CC bonding with CO bonding. For ABS, wavenumber 1472 cm⁻¹ -1 , 1555cm -1 , 1639cm -1A clear peak appeared in the band. These wavenumbers are known to originate from aromatic ring CC bonds, and the peaks observed at these wavenumbers for ABS are thought to be due to the phenyl group of ABS. Similarly, numerous peaks appeared in the same band for PI, suggesting that molecules containing aromatic rings obtained from the decomposition of PI became gases and were detected. For CO bonds, 1112 cm⁻¹ was observed. -1 , 1238cm -1 For the C=C bond, the band is 1795 cm². -1 It is known that peaks appear in these bands. For PLA, peaks were detected in these bands. This suggests that PLA contains both CO bonds and C=C bonds, and that these bonds were maintained during thermal decomposition while vaporizing. For PET, peaks were also detected at wavenumber 1112 cm⁻¹. -1 , 1238cm -1 The presence of a peak in the band suggests that gas originating from CO bonding is being produced. For PC, PS, and PET, multiple peaks are observed, which are thought to originate from aromatic ring CC bonds. No significant peaks were observed for PE and PP. This is likely because these molecules do not contain oxygen or aromatic rings. 【0050】 Using Figure 5, the wavenumber 600 cm in Figure 2 -1 From 900cm -1 The spectra of each carbon-containing gas in the region are shown. Multiple peaks were observed for PI, PC, PS, and PET. The 713 cm⁻¹ peak observed for PI is shown. -1 The peak observed for PC, PS, and PET is thought to originate from the CC bond of the aromatic ring. No significant peaks were observed for PP, PE, ABS, and PLA. 【0051】 To summarize, the results are shown in Table 1. [Table 1] 【0052】 PE and PP are thought to be gases containing molecules or intermediates composed of alkyl chains. Specifically, PE is thought to be gases such as the linear alkanes butane, pentane, and hexane. PP has a polymeric structure in which CH3 is bonded to a linear alkane, so in addition to butane, pentane, and hexane derived from the linear alkanes, it is thought to be composed of their structural isomers, isobutane and neopentane. For similar reasons, it is also thought to be a cycloalkane with a single CC bond. Furthermore, it is possible that H2 is produced during the decomposition of PE and PP. There is also the possibility of the presence of -CH3, -CH2, and ionized protons that retain unbonded bonds. 【0053】 Regarding ABS, it is thought that the polymers that make up the polymer—acrylonitrile (C3H3N), butadiene (CH2=CH-CH=CH2), and styrene (C8H8)—are monomerized or further decomposed and gasified. The difference from PE and PP is that the above three monomers have a C=C double bond (alkene). In other words, in the case of ABS, the alkenes ethylene (C2H4), propylene (C3H6), butene (C4H8), and pentene-butene (C5H 10 ), Hexenbutene (C6H 12 It is thought that these monomers exist as gases. In addition, it is thought that these monomers are cracked and become phenyl groups, vinyl groups, etc. On the other hand, since no oxygen-related bonds such as CO or C=O were observed, carboxylic acids, aldehydes, ketones, alcohols, etc. are not present. 【0054】 For PI, peaks were mainly obtained from the aromatic ring CC and imide bond, suggesting that a completely different molecule was formed compared to PE, PP, and ABS. PI has a rigid and strong structure due to its conjugated structure directly bonded to the aromatic ring by an imide bond. Therefore, it is thought that the bond was broken starting from the oxygen atom bonding the aromatic ring, generating a phenyl group. It is also thought that an intermediate containing some imide bonds was simultaneously formed. Similar to PE and PP, no molecules containing -CH3 and / or -CH2 were formed. For PC and PS, it is thought that a gas containing molecules with -CH3 and / or -CH2 and an aromatic ring was obtained, i.e., a gas similar to a mixture of PI and the gas produced by PE and PP. For PET and PLA, peaks attributable to CH3, CH2, and oxygen were observed. 【0055】 Furthermore, no peaks attributable to acetylene were observed in any of the raw material resins 144. This can be understood from the fact that none of the raw material resins 144 have a CC triple bond. 【0056】 Figure 6 shows the relationship between the time from the start of introducing the carbon-containing gas into the quartz tube 130 and the length of the carbon nanotubes (CNTs), i.e., the CNT growth rate, when PC is used as the raw material resin 144. Figure 7 shows an electron microscope image taken 32 minutes after the start of introducing the carbon-containing gas into the quartz tube 130. Referring to Figure 6, it can be seen that the growth rate is approximately 7-8 μm per minute. Referring to Figure 7, it can be seen that thin, linear carbon nanotubes are obtained. 【0057】 Figure 8 shows the Raman spectrum of the generated carbon nanotubes, and Figure 9 shows I g / I d The ratio is shown. Referring to Figure 8, for all raw material resins 144, approximately 1340 cm³ -1 D Peak is located at approximately 1570cm. -1 A G peak was observed. These two peaks are unique to carbon nanotubes, indicating that carbon nanotubes were being produced by this embodiment. Referring to Figure 9, I g / I dThe ratios obtained were approximately 2.9 for PS, 1.0 or higher for PE, PP, PI, PET, and PLA, and approximately 1.0 for ABS and PC. This indicates that high-quality carbon nanotubes are produced by this embodiment. 【0058】 Based on the above, the conversion efficiency from raw material resin 144 to carbon nanotubes using the carbon nanotube manufacturing apparatus and manufacturing method according to this embodiment will be explained. First, the number of carbon atoms per unit mass of the raw material resin 144 is N t We will find the number of carbon atoms N. t It can be calculated using the following formula. 【number】 However, W u This is the molecular weight per unit unit, N C This is the number of carbon atoms per low molecular weight unit, N A Avogadro's number (6.022 × 10⁻¹⁰) is Avogadro's number. 23 / mol), W p This represents the amount of vaporized raw resin. 【0059】 Next, the mass M per low molecular weight unit that makes up the polymer. u Calculate (g / u). Mass M per unit unit. u (g / u) is M u =W u / N A It is expressed as follows: For example, in the case of PE, the low molecular weight unit is composed of 2 C and 4 H, so the molecular weight per unit unit is W u It is 28.1 g / mol·u. Therefore, in PE, the mass M per low molecular weight unit is u = 4.67 × 10 -23 It's g / u. 【0060】 Next, we determine the number of carbon atoms N per unit mass (carbons / g). C If we let (number / u), then N = N C / M u It is represented as follows: In the case of PE, N c Since = 2, N = 4.27 × 10 22It is pieces / g. And the amount of vaporized raw material resin W p Therefore, the number of carbon atoms in the raw material N t However, N t =N×W p It can be determined as follows. For example, if 0.3g of PE is added as a raw material for carbon nanotubes, the number of carbon atoms will be N t (PE) = 1.29 × 10 22 The number of units per input amount (0.3g) can be calculated. Even if the amount of vaporized raw resin is the same, the size of the low molecular weight units and the number of carbon atoms per unit unit differ depending on the type of raw resin, so the number of carbon atoms N per unit mass differs depending on the type of plastic. 【0061】 Next, we determine the number of carbon atoms that make up the generated carbon nanotubes. (Cat number N) CNT It can be calculated using the following formula. 【number】 However, δ is the number of carbon atoms per unit axial length and per unit circumference (38.12 atoms / nm), L (nm) is the average length of the carbon nanotube, and S (cm) is the average length of the carbon nanotube. 2 ) is the growth area, d (plants / cm²) 2 ) represents the growth density, r0 (nm) is the radius of the outermost shell of the multi-walled carbon nanotube (MWNT), P is the number of layers in the MWNT, and 0.334 is the interlayer distance. From the above equations 1 and 2, the conversion efficiency η can be calculated using the following formula. 【number】 【0062】 The conversion efficiency was derived from the properties of the carbon nanotubes obtained in this embodiment. Table 2 shows the conversion efficiency. [Table 2] 【0063】 According to this embodiment, a carbon nanotube manufacturing method and apparatus capable of producing carbon nanotubes in high yield have been obtained. While Patent Document 1 discloses a yield of approximately 4%, the method for calculating it is not disclosed. However, in this embodiment, a yield higher than 4% was obtained, except for PET and PLA, using the above-mentioned yield calculation method. Furthermore, according to this embodiment, carbon nanotubes can be manufactured without requiring special steps such as pre-preparing carbon-containing gases and / or catalyst gases. 【0064】 Next, the second manufacturing apparatus 200 according to the second embodiment will be described with reference to Figure 10. Components similar to those in the first embodiment are denoted by the same reference numerals and their description is omitted. 【0065】 The second manufacturing apparatus 200 mainly comprises a mass flow controller 110, a growth furnace 120, a quartz tube 130, a resin combustion furnace 232, a pressure gauge 150, a solenoid valve 160, a pressure regulating valve 170, and a needle valve 180. In this embodiment, the raw material vaporization section corresponds to the resin combustion furnace 232, and differs from the first embodiment in that it is provided as a separate resin combustion furnace 232 rather than being located near the inlet end of the growth furnace 120. The mass flow controller 110, growth furnace 120, pressure gauge 150, solenoid valve 160, pressure regulating valve 170, and needle valve 180 are the same as in the first embodiment, so their description is omitted. 【0066】 For the quartz tube 130, the outer diameter, inner diameter, and radial thickness are the same as in the first embodiment, but a length is selected that extends over the entire length of the resin combustion furnace 232 and the growth furnace 120, depending on the length and positional relationship between the resin combustion furnace 232 and the growth furnace 120. 【0067】 The resin combustion furnace 232 is capable of adjusting the temperature inside the furnace to any temperature suitable for the thermal decomposition temperature of each raw resin, such as 400°C. For example, a product named ARF-30K manufactured by Asahi Rika Seisakusho is used. The resin combustion furnace 232 is installed between the inlet piping 102 and the growth furnace 120. 【0068】 The raw resin 144 is placed inside the resin combustion furnace 232 within the quartz tube 130. The catalyst metal 142 is made of, for example, ferrocene and is placed inside the quartz tube 130 at a predetermined distance from the inlet end of the growth furnace 120. 【0069】 Next, a process for producing carbon nanotubes, including one embodiment of the present invention, will be described. Throughout this process, negative pressure is applied to the exhaust pipe 108. 【0070】 First, a substrate 146 is placed in the longitudinal center of the quartz tube 130, raw material resin 144 is placed in the resin combustion furnace 232, and catalyst metal 142 is placed in the catalyst sublimation section 134. Next, a vacuuming process is performed. This process is the same as in the first embodiment, so the explanation is omitted. 【0071】 Next, a gas introduction and heating process is performed. In this process, the flow rate in the mass flow controller 110 is set to 300 sccm, the pressure adjustment valve 170 is opened, and the solenoid valve 160 is closed. Then, the needle valve 180 is adjusted to adjust the pressure inside the quartz tube 130 to -20 kPa. As a result, the carrier gas Ar / H2 is introduced into the quartz tube 130, and the solenoid valve 160 is kept closed. The concentration of the carrier gas Ar / H2 inside the quartz tube 130 is approximately 3%. Then, the resin combustion furnace 232 and the growth furnace 120 raise the temperature inside the furnaces, respectively. The temperature inside the resin combustion furnace 232 is a temperature suitable for the thermal decomposition temperature of each raw material resin, as described in the first embodiment. As a result, the raw material resin 144 vaporizes into a carbon-containing gas, and the catalyst metal 142 sublimes into a catalyst gas and changes its form into catalyst metal fine particles. 【0072】 Next, a growth treatment is performed. In this treatment, the needle valve 180 is maintained at the position adjusted during the gas introduction and heating treatment, and the pressure adjustment valve 170 is kept open. As the temperature inside the quartz tube 130 rises due to the heating of the resin combustion furnace 232 and the growth furnace 120, the raw material resin 144 and catalyst metal 142 are thermally decomposed, vaporizing and sublimating into carbon-containing gas and catalyst gas (raw material vaporization step and catalyst sublimation step), which flow toward the substrate 146. At this time, the catalyst gas becomes catalyst metal nanoparticles in the space of the quartz tube 130 and on the inner wall of the quartz tube 130 and the surface of the substrate 146 (morphological change step). If only the carbon-containing gas comes into contact with the inner wall of the quartz tube 130 or the substrate 146 in an environment where catalyst metal nanoparticles are absent, amorphous carbon will grow, hindering the formation of carbon nanotubes. Therefore, catalyst metal nanoparticles are formed simultaneously with and / or before the carbon-containing gas on the inner wall of the quartz tube 130 or the surface of the substrate 146. Here, "simultaneous" includes not only the exact same moment, but also the time from 0 to approximately 240 seconds from when the catalyst gas comes into contact with the inner wall of the quartz tube 130 and the substrate 146 until the carbon-containing gas comes into contact with the inner wall of the quartz tube 130 and the substrate 146. As the raw material resin 144 and catalyst metal 142 vaporize and sublimate, the pressure inside the quartz tube 130 increases. As mentioned above, the electromagnetic valve 160 is set to automatically open when the pressure value from the pressure gauge 150 is -15kPa or higher relative to atmospheric pressure, and to automatically close when it is -20kPa or lower relative to atmospheric pressure. Therefore, when the pressure value measured by the pressure gauge 150 is -15kPa or higher, the electromagnetic valve 160 automatically opens and lowers the pressure inside the quartz tube 130. Then, when the pressure inside the quartz tube 130 drops to -20kPa or lower, the electromagnetic valve 160 automatically closes. In this way, the pressure inside the quartz tube 130 is maintained within the range of -15 to -20kPa. In this embodiment, a state in which the pressure inside the quartz tube 130 is in the range of -15 to -20 kPa is considered to be a state in which the pressure inside the quartz tube 130 is kept constant. By performing the growth process for a predetermined period of time, carbon nanotubes are formed and grown on the substrate 146. 【0073】 When terminating the carbon nanotube production, the carbon-containing gas may be stopped first, followed by the catalyst gas; the carbon-containing gas and catalyst gas may be stopped simultaneously; or the catalyst gas may be stopped first, followed by the carbon-containing gas. In other words, the resin combustion furnace 232 may be stopped first, followed by the growth furnace 120; the growth furnace 120 and the resin combustion furnace 232 may be stopped simultaneously; or the growth furnace 120 may be stopped first, followed by the resin combustion furnace 232. When stopping the catalyst gas first, it is preferable to stop the supply of the carbon-containing gas within, for example, one hour after stopping the catalyst gas. The reason for this is explained below. 【0074】 After the catalytic gas supply is stopped, the catalytic metal contained in the already formed carbon nanotubes retains catalytic activity for a certain period of time. When a carbon-containing gas is supplied, carbon nanotubes grow using this catalytic activity. However, when the catalytic activity decreases, carbon nanotubes are not formed, and amorphous carbon is produced instead. In this embodiment, ferrocene is used as the catalyst. In this case, Fe nanoparticles are generated at the base of the carbon nanotubes, and carbon nanotubes may grow using these nanoparticles as seeds. If a carbon-containing gas is supplied after the catalytic activity has decreased due to the lack of catalytic gas supply, carbon nanotubes may be formed using the Fe nanoparticles generated and remaining at the base of the carbon nanotubes as a catalyst. However, since it takes time for the carbon-containing gas to reach the base of the carbon nanotubes, it is possible that the carbon-containing gas will become amorphous carbon before reaching the base. On the other hand, when nickelosene is used as the catalyst, Ni nanoparticles are generated at the tip of the carbon nanotubes (tip growth). Therefore, if the catalyst gas is continuously supplied after the catalytic gas is depleted, carbon nanotubes may continue to be produced. In light of the above circumstances, it is preferable to stop supplying the carbon-containing gas within, for example, one hour after stopping the catalytic gas supply, until the catalytic activity of the catalytic gas is lost. Furthermore, it is preferable that the time interval between the moment when the raw material resin 144 is supplied to the substrate 146 as a carbon-containing gas and / or comes into contact with it, and the moment when the catalytic metal 142 is supplied to the substrate 146 as a catalytic gas and / or comes into contact with it, be short. This can reduce the consumption of the catalytic metal 142. 【0075】 According to this embodiment, the same effects as in the first embodiment can be obtained. Furthermore, by using the resin combustion furnace 232, the temperature inside the furnace can be set precisely and over a wide range, thereby enabling precise and wide control of the resin vaporization temperature, as well as more precise control of the timing of introducing the carbon-containing gas into the growth furnace 120. In addition, since the resin combustion furnace 232 tends to have a larger space for installing the raw material resin 144 than the raw material vaporization section 132, a large amount of raw material resin 144 can be introduced, thereby enabling the growth of carbon nanotubes over a long period of time. As a result, according to this embodiment, high-quality carbon nanotubes can be produced efficiently. 【0076】 The order of the resin combustion furnace 232 and the catalyst sublimation section 134 may be reversed, and the order from the inlet pipe 102 may be catalyst sublimation section 134, resin combustion furnace 232, and growth furnace 120. In this case, the distance from the catalyst metal 142 to the inlet end of the resin combustion furnace 232 is such that the catalyst metal 142 can receive enough heat from the resin combustion furnace 232 to sublimate. 【0077】 Next, a third manufacturing apparatus 300 according to the third embodiment will be described using Figure 11. Components similar to those in the first and second embodiments are denoted by the same reference numerals and their description is omitted. 【0078】 The third manufacturing apparatus 300 mainly comprises a mass flow controller 110, a growth furnace 120, a quartz tube 130, a resin combustion furnace 232, a catalytic sublimation furnace 334, a pressure gauge 150, a solenoid valve 160, a pressure regulating valve 170, and a needle valve 180. In this embodiment, the raw material vaporization section corresponds to the resin combustion furnace 232, and compared to the first embodiment, it is provided as a separate resin combustion furnace 232 rather than near the inlet end of the growth furnace 120. The catalytic sublimation section corresponds to the catalytic sublimation furnace 334, and compared to the first embodiment, it is provided as a separate catalytic sublimation furnace 334 rather than near the inlet end of the growth furnace 120. The mass flow controller 110, growth furnace 120, pressure gauge 150, solenoid valve 160, pressure regulating valve 170, and needle valve 180 are the same as in the first embodiment, so their description is omitted. 【0079】 For the quartz tube 130, the outer diameter, inner diameter, and radial thickness are the same as in the first embodiment, but a length is selected that extends along the entire length of each, from the resin combustion furnace 232 through the catalytic sublimation furnace 334 to the growth furnace 120, depending on the length and positional relationship of the resin combustion furnace 232, the catalytic sublimation furnace 334, and the growth furnace 120. 【0080】 The resin combustion furnace 232 is capable of adjusting the temperature inside the furnace to any temperature, such as 400°C, which is suitable for the thermal decomposition temperature of each raw material resin. For example, a product named ARF-30K manufactured by Asahi Rika Seisakusho is used. The raw material resin 144 is placed inside the resin combustion furnace 232 within the quartz tube 130. 【0081】 The catalytic sublimation furnace 334 is capable of adjusting the temperature inside the furnace to any temperature suitable for sublimating the catalyst metal, such as 150°C. For example, a product named ARF-30K manufactured by Asahi Rika Seisakusho is used. The catalyst metal 142 consists of, for example, ferrocene and is installed inside the catalytic sublimation furnace 334. Starting from the inlet piping 102, the resin combustion furnace 232, the catalytic sublimation furnace 334, and the growth furnace 120 are installed in that order. 【0082】 Next, a method for manufacturing carbon nanotubes, including one embodiment of the present invention, will be described. Throughout this process, negative pressure is applied to the exhaust pipe 108. 【0083】 First, a substrate 146 is placed in the longitudinal center of the quartz tube 130, raw material resin 144 is placed in the resin combustion furnace 232, and catalyst metal 142 is placed in the catalyst sublimation furnace 334. Next, a vacuum treatment is performed. This treatment is the same as in the first embodiment, so the explanation is omitted. 【0084】 Next, a gas introduction and heating process is performed. In this process, the flow rate in the mass flow controller 110 is set to 300 sccm, the pressure adjustment valve 170 is opened, and the solenoid valve 160 is closed. Then, the needle valve 180 is adjusted to adjust the pressure inside the quartz tube 130 to -20 kPa. As a result, the carrier gas Ar / H2 is introduced into the quartz tube 130, and the solenoid valve 160 is kept closed. The concentration of the carrier gas Ar / H2 inside the quartz tube 130 is approximately 3%. Then, the resin combustion furnace 232, the catalyst sublimation furnace 334, and the growth furnace 120 each raise the temperature inside the furnace. The temperature inside the resin combustion furnace 232 is a temperature suitable for the thermal decomposition temperature of each raw material resin, as described in the first embodiment. The temperature inside the catalyst sublimation furnace 334 is a temperature suitable for the sublimation of the catalyst metal, as described in the first embodiment. As a result, the raw material resin 144 vaporizes into a carbon-containing gas, and the catalyst metal 142 sublimes into a catalyst gas. 【0085】 Next, a growth treatment is performed. In this treatment, the needle valve 180 is maintained at the position adjusted during the gas introduction and heating treatment, and the pressure adjustment valve 170 is kept open. As the temperature inside the quartz tube 130 rises due to the heating of the resin combustion furnace 232 and the growth furnace 120, the raw material resin 144 and catalyst metal 142 are thermally decomposed, vaporizing and sublimating into carbon-containing gas and catalyst gas (raw material vaporization step and catalyst sublimation step), which flow toward the substrate 146. At this time, the catalyst gas becomes catalyst metal nanoparticles in the space of the quartz tube 130 and on the inner wall of the quartz tube 130 and the surface of the substrate 146 (morphological change step). If only the carbon-containing gas comes into contact with the inner wall of the quartz tube 130 or the substrate 146 in an environment where catalyst metal nanoparticles are absent, amorphous carbon will grow, hindering the formation of carbon nanotubes. Therefore, catalyst metal nanoparticles are formed on the inner wall of the quartz tube 130 or the surface of the substrate 146 simultaneously with and / or before the carbon-containing gas. Here, "simultaneous" includes not only the exact same moment, but also the time from 0 to approximately 240 seconds from when the catalyst gas comes into contact with the inner wall of the quartz tube 130 and the substrate 146 until the carbon-containing gas comes into contact with the inner wall of the quartz tube 130 and the substrate 146. As the raw material resin 144 and catalyst metal 142 vaporize and sublimate, the pressure inside the quartz tube 130 increases. As mentioned above, the electromagnetic valve 160 is set to automatically open when the pressure value from the pressure gauge 150 is -15kPa or higher relative to atmospheric pressure, and to automatically close when it is -20kPa or lower relative to atmospheric pressure. Therefore, when the pressure value measured by the pressure gauge 150 is -15kPa or higher, the electromagnetic valve 160 automatically opens and lowers the pressure inside the quartz tube 130. Then, when the pressure inside the quartz tube 130 drops to -20kPa or lower, the electromagnetic valve 160 automatically closes. In this way, the pressure inside the quartz tube 130 is maintained within the range of -15 to -20kPa. In this embodiment, a state in which the pressure inside the quartz tube 130 is in the range of -15 to -20 kPa is considered to be a state in which the pressure inside the quartz tube 130 is kept constant. By performing the growth process for a predetermined period of time, carbon nanotubes are formed and grown on the substrate 146. 【0086】 When terminating the carbon nanotube production, the carbon-containing gas may be stopped first, followed by the catalyst gas; the carbon-containing gas and catalyst gas may be stopped simultaneously; or the catalyst gas may be stopped first, followed by the carbon-containing gas. In other words, the resin combustion furnace 232 may be stopped first, followed by the catalyst sublimation furnace 334 and / or the growth furnace 120; the growth furnace 120, the resin combustion furnace 232, and the catalyst sublimation furnace 334 may be stopped simultaneously; or the catalyst sublimation furnace 334 may be stopped first, followed by the resin combustion furnace 232. In addition, as in the second embodiment, when the catalyst gas is stopped first, followed by the carbon-containing gas, it is preferable to stop the supply of the carbon-containing gas within, for example, one hour after the catalyst gas is stopped. 【0087】 This embodiment provides the same effects as the first and second embodiments. Furthermore, by using the catalytic sublimation furnace 334, the temperature inside the furnace can be set precisely and over a wide range, thereby allowing for precise and wide control of the sublimation temperature of the catalyst metal 142, as well as more precise control of the timing of flowing the catalyst gas into the growth furnace 120. The size of the catalyst metal particles tends to change depending on the amount of catalyst gas, so by precisely and wide-ranging the sublimation temperature of the catalyst metal 142, the size of the catalyst metal particles can be controlled, thereby controlling the thickness of the carbon nanotubes. In addition, since the catalytic sublimation furnace 334 tends to have a larger space for installing the catalyst metal 142 than the catalytic sublimation section 134, a large amount of catalyst metal 142 can be introduced, thereby allowing for the growth of carbon nanotubes over a long period of time. Moreover, by vaporizing the raw material resin 144 using the resin combustion furnace 232 and sublimating the catalyst metal 142 using the catalytic sublimation furnace 334, the timing of flowing the carbon-containing gas and catalyst gas into the growth furnace 120 can be controlled more precisely. Therefore, according to this embodiment, high-quality carbon nanotubes can be produced efficiently. 【0088】 The order of the resin combustion furnace 232 and the catalytic sublimation furnace 334 may be reversed, and the order from the inlet pipe 102 may be catalytic sublimation furnace 334, resin combustion furnace 232, and growth furnace 120. 【0089】 Next, the fourth manufacturing apparatus 400 according to the fourth embodiment will be described using Figures 12 to 14. Components similar to those in the first to third embodiments are denoted by the same reference numerals and their description is omitted. 【0090】 Referring to Figure 12, the fourth manufacturing apparatus 400 mainly comprises a mass flow controller 110, a growth furnace 120, a quartz tube 130, a pressure gauge 150, a solenoid valve 160, a pressure regulating valve 170, and a needle valve 180. This embodiment differs from the first embodiment in that carbon nanotubes are grown on the inner wall of the growth furnace 120 without using a substrate 146, and a metal piece 446 is installed inside the growth furnace 120 to provide a catalyst sublimation section 434 inside the growth furnace 120. The mass flow controller 110, the growth furnace 120, the pressure gauge 150, the solenoid valve 160, the pressure regulating valve 170, and the needle valve 180 are the same as in the first embodiment, so their description is omitted. 【0091】 The quartz tube 130 has the same outer diameter, inner diameter, and radial thickness as in the first embodiment, but since the catalyst sublimation section 134 of the first embodiment is not provided, its length may be shorter than that of the first embodiment. 【0092】 The metal piece 446 is made of, for example, ferrocene and / or stainless steel, and is placed approximately in the center of the growth furnace 120 within the quartz tube 130, functioning as both a substrate and a catalyst. The form of the metal piece 446 is preferably a metal rod, a metal mesh, a transition metal thin film, a bulk material, and / or fine particles. In this embodiment, a portion of the quartz tube 130 in which the metal piece 446 is placed forms the catalyst sublimation section 434. 【0093】 Next, a method for producing carbon nanotubes, including one embodiment of the present invention, will be described. Throughout the entire process of this method, negative pressure is applied to the exhaust pipe 108. 【0094】 First, a metal piece 446 is placed in the catalyst sublimation section 434 located in the longitudinal center of the quartz tube 130, and the raw material resin 144 is placed in the raw material vaporization section 132. Next, a vacuum treatment is performed. This treatment is the same as in the first embodiment, so the explanation is omitted. 【0095】 Next, a gas introduction and heating process is performed. In this process, the flow rate in the mass flow controller 110 is set to 300 sccm, the pressure regulating valve 170 is opened, and the solenoid valve 160 is closed. Then, the needle valve 180 is adjusted to adjust the pressure inside the quartz tube 130 to -20 kPa. As a result, the carrier gas Ar / H2 is introduced into the quartz tube 130, and the solenoid valve 160 is kept closed. The concentration of the carrier gas Ar / H2 inside the quartz tube 130 is approximately 3%. Then, the growth furnace 120 raises the temperature inside the furnace. As a result, the raw material resin 144 vaporizes into a carbon-containing gas, and the metal pieces 446 sublimate into a catalyst gas. 【0096】 Next, a growth treatment is performed. In this treatment, the needle valve 180 is maintained at the position adjusted during the gas introduction and heating treatment, and the pressure adjustment valve 170 is kept open. As the temperature inside the quartz tube 130 rises due to the heating of the growth furnace 120, the raw material resin 144 and metal piece 446 undergo thermal decomposition, vaporizing and sublimating into a carbon-containing gas and a catalyst gas (raw material vaporization step and catalyst sublimation step), and the carbon-containing gas flows toward the metal piece 446. At this time, the catalyst gas becomes catalyst metal nanoparticles in the space of the quartz tube 130 and on the surface of the inner wall of the quartz tube 130 (morphological change step). If only the carbon-containing gas comes into contact with the inner wall of the quartz tube 130 in an environment where catalyst metal nanoparticles are absent, amorphous carbon will grow, and the formation of carbon nanotubes will be hindered. Therefore, catalyst metal nanoparticles are formed on the inner wall surface of the quartz tube 130 simultaneously with and / or before the carbon-containing gas. Here, "simultaneous" includes not only the perfectly identical moment, but also the time from 0 to approximately 240 seconds from when the catalyst gas comes into contact with the inner wall surface of the quartz tube 130 until the carbon-containing gas comes into contact with the inner wall surface of the quartz tube 130. As the raw material resin 144 and metal piece 446 vaporize and sublimate, the pressure inside the quartz tube 130 increases. As previously mentioned, the electromagnetic valve 160 is set to automatically open when the pressure value from the pressure gauge 150 is -15kPa or higher relative to atmospheric pressure, and to automatically close when it is -20kPa or lower relative to atmospheric pressure. Therefore, when the pressure value measured by the pressure gauge 150 is -15kPa or higher, the electromagnetic valve 160 automatically opens and lowers the pressure inside the quartz tube 130. Then, when the pressure inside the quartz tube 130 drops to -20kPa or lower, the electromagnetic valve 160 automatically closes. In this way, the pressure inside the quartz tube 130 is maintained within the range of -15 to -20kPa. In this embodiment, a state in which the pressure inside the quartz tube 130 is in the range of -15 to -20 kPa is considered to be a state in which the pressure inside the quartz tube 130 is kept constant. By performing the growth treatment for a predetermined period of time, carbon nanotubes are formed and grown on the metal piece 446. 【0097】 Figure 13 is an electron microscope image of carbon nanotubes formed using a stainless steel rod as metal piece 446. The growth of the carbon nanotubes can be clearly seen. 【0098】 Figure 14 is an electron microscope image of carbon nanotubes formed using a stainless steel metal mesh as metal piece 446. The growth of carbon nanotubes can be clearly seen. 【0099】 According to this embodiment, the same effects as in the first embodiment can be obtained. Furthermore, since a substrate is not required, the time and cost required for preparation can be reduced. 【0100】 In the first to third embodiments, it was explained that carbon nanotubes are produced using the substrate 146, but the substrate 146 is not required. The carbon nanotubes grow on the inner wall of the quartz tube 130. Alternatively, an alumina tube may be used instead of the quartz tube 130. 【0101】 In all embodiments, the carrier gas is not limited to Ar / H2, but may be pure argon, which is a gas containing only Ar, or another inert gas. 【0102】 In any embodiment, the raw material resin 144 is not limited to those described above, and may be AS resin, methacrylic resin (PMMA), polyamide (PA), polyacetal (POM), modified polyphenylene ether (m-PPE), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyarylate (PAR), polysulfone (PSU), polyethersulfone (PES), polyetheretherketone (PEEK), polyetherimide (PEI), liquid crystal polymer (LCP), fluororesin, thermoplastic elastomer, polymethylpentene (PMP), biodegradable plastic, fiber-based plastic, phenolic resin (PF), urea resin (UF), melamine resin (MF), epoxy resin (EP), unsaturated polyester resin (UP), polyurethane (PU), diallyl phthalate resin (PDAP), silicone resin (SI), alkyd resin, and combinations thereof. Furthermore, the raw material resin 144 may be waste containing these resins. 【0103】 In all embodiments, the catalyst metal 142 is not limited to those described above, and is preferably, but not limited to, organometallic materials including Fe, Ni, Co, and combinations thereof, such as nickerosene, cobaltocene, Fe phthalocyanine, Ni phthalocyanine, metal-organic frameworks (MOFs) in which metals and organic materials are arranged in a lattice, and / or those containing Al. 【0104】 In addition, in any embodiment, the temperature of the heat applied to the raw material resin 144, catalyst metal 142, and metal piece 446 is not limited to those described above, and any temperature sufficient for vaporization and sublimation is acceptable. 【0105】 The size, shape, quantity, and temperature of each component shown in this specification and in the figures are illustrative and not limited thereto. Furthermore, the material of each component is illustrative and not limited thereto. 【0106】 Embodiments of the present invention have been described with reference to the accompanying drawings, but it will be obvious to those skilled in the art that modifications can be made to the structure and relationships of the parts without departing from the scope and spirit of the invention described herein. [Explanation of symbols] 【0107】 100 First manufacturing apparatus 110 Mass Flow Controller 120 Growth Furnace (Growth Department) 130 Quartz tube 150 pressure gauge 160 Solenoid valve 170 Pressure regulating valve 180 Needle Valve

Claims

[Claim 1] A raw material vaporization step in which the resin is vaporized to obtain a carbon-containing gas, A catalyst sublimation step in which a catalyst metal is sublimated to obtain a catalyst gas, A contact step of bringing the catalyst gas and the carbon-containing gas into contact, The system includes a control step of maintaining the pressure in the space where the carbon-containing gas and the catalyst gas are present at -15 kPa or more and -20 kPa or less. The contact step is performed using a growth section, and the catalyst sublimation step is performed using a catalyst sublimation section provided outside the growth section. Method for manufacturing carbon nanotubes. [Claim 2] The carbon nanotube manufacturing method according to claim 1, further comprising a morphological change step of thermally decomposing the catalyst gas to change its form into catalyst metal nanoparticles. [Claim 3] The carbon nanotube production method according to claim 1 or 2, wherein the contact step involves growing carbon nanotubes by chemical vapor deposition. [Claim 4] The aforementioned raw material vaporization step involves vaporizing the resin in the raw material vaporization section. The catalyst sublimation step involves sublimating the catalyst metal in the catalyst sublimation section. The aforementioned space is a growth section, The control step involves introducing a carrier gas into the raw material vaporization section, the catalyst sublimation section, and the growth section, and maintaining the pressure in the growth section at -15 kPa or more and -20 kPa or less. A method for producing carbon nanotubes according to any one of claims 1 to 3. [Claim 5] The method for producing carbon nanotubes according to any one of claims 1 to 4, wherein the raw material vaporization step involves heating the resin at a temperature corresponding to the resin to cause thermal decomposition, and the catalyst sublimation step involves heating the catalyst metal at a temperature corresponding to the catalyst metal to cause sublimation. [Claim 6] The carbon nanotube manufacturing method according to any one of claims 1 to 5, wherein the contact step involves heating the wall surface forming the space to 500°C or more and 900°C or less, and the carbon nanotubes grow on the wall surface. [Claim 7] The carbon nanotube manufacturing method according to any one of claims 1 to 6, wherein the contact step involves heating a substrate placed in the space to 500°C or more and 900°C or less, and the carbon nanotubes grow on the substrate. [Claim 8] The method for producing carbon nanotubes according to any one of claims 1 to 7, wherein the catalyst metal is an organometallic molecule containing Fe, Ni, Co, and combinations thereof. [Claim 9] The method for producing carbon nanotubes according to any one of claims 1 to 8, wherein the resin is polyethylene (PE), polypropylene (PP), acrylonitrile butadiene styrene (ABS), polystyrene (PS), polylactic acid (PLA), polycarbonate (PC), polyimide (PI), polyethylene terephthalate (PET), polyvinyl chloride (PVC), or any combination thereof. [Claim 10] The carbon nanotube manufacturing method according to any one of claims 1 to 9, characterized in that the carbon nanotube is multilayered and carbon nanotubes are grown in an amount of 1% by mass or more and 81% by mass or less of the resin. [Claim 11] A raw material vaporization unit that vaporizes resin to obtain a carbon-containing gas, A catalyst sublimation section that sublimes a catalyst metal to obtain a catalyst gas, A growth section that brings the catalyst gas and the carbon-containing gas into contact, A control unit that maintains the pressure within the growth section at -15 kPa or more and -20 kPa or less. Equipped with, The catalyst sublimation section is provided outside the growth section. Carbon nanotube manufacturing equipment. [Claim 12] The carbon nanotube manufacturing apparatus according to claim 11, wherein the growth section thermally decomposes the catalyst gas to change its shape into catalyst metal nanoparticles. [Claim 13] The carbon nanotube manufacturing apparatus according to claim 11 or 12, wherein the growth section grows carbon nanotubes by chemical vapor deposition. [Claim 14] The carbon nanotube manufacturing apparatus according to any one of claims 11 to 13, wherein the control unit introduces a carrier gas into the raw material vaporization unit, the catalyst sublimation unit, and the growth unit, and maintains the pressure in the growth unit at -15 kPa or more and -20 kPa or less. [Claim 15] The carbon nanotube manufacturing apparatus according to any one of claims 11 to 14, wherein the growth section is provided downstream of the raw material vaporization section and the catalyst sublimation section. [Claim 16] The carbon nanotube manufacturing apparatus according to any one of claims 11 to 15, wherein the control unit comprises a pressure sensor for detecting the internal pressure of the growth section and a valve for adjusting the internal pressure of the growth section. [Claim 17] The carbon nanotube manufacturing apparatus according to any one of claims 11 to 16, wherein the growth section heats the wall surface forming the growth section to 500°C or more and 900°C or less, and the carbon nanotubes grow on the wall surface. [Claim 18] The carbon nanotube manufacturing apparatus according to any one of claims 11 to 17, wherein the growth section heats a substrate placed within the growth section to 500°C or more and 900°C or less, and the carbon nanotubes grow on the substrate. [Claim 19] The carbon nanotube manufacturing apparatus according to any one of claims 11 to 18, wherein the catalyst metal is an organometallic molecule containing Fe, Ni, Co, and combinations thereof. [Claim 20] The carbon nanotube manufacturing apparatus according to any one of claims 11 to 19, wherein the resin is any of polyethylene (PE), polypropylene (PP), acrylonitrile butadiene styrene (ABS), polystyrene (PS), polylactic acid (PLA), polycarbonate (PC), polyimide (PI), polyethylene terephthalate (PET), polyvinyl chloride (PVC), and any combination thereof. [Claim 21] The carbon nanotube manufacturing apparatus according to any one of claims 11 to 20, characterized in that the carbon nanotubes are multilayered and carbon nanotubes are grown in an amount of 1% by mass or more and 81% by mass or less of the resin.

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