JP6667849B2 - Method for manufacturing spinning source member having carbon nanotube forest - Google Patents

Description

  The present invention relates to a method for producing a carbon nanotube forest, a spinning source member, a structure, and a composite structure. More specifically, the present invention relates to a method for manufacturing a carbon nanotube forest, a spinning source member including the carbon nanotube forest manufactured by the manufacturing method, a structure formed from the spinning source member, and a composite structure including the structure as a skeletal structure. .

  In this specification, a carbon nanotube forest (also referred to as “CNT forest” in this specification) is a synthetic structure of a plurality of carbon nanotubes (also referred to as “CNT” in this specification). The individual shape of the given CNT is referred to as a “primary structure” and the above-described composite structure is referred to as a “secondary structure.” The plurality of CNTs have a certain direction (at least a part of the major axis direction). As a specific example, a direction substantially parallel to one normal line of the surface of the substrate can be mentioned.) It means an aggregate of CNTs grown so as to be oriented. The length (height) of the CNT forest grown from the substrate in a direction parallel to the normal line of the substrate in a state of being attached to the substrate is referred to as “growth height”.

  Further, in the present specification, a plurality of CNTs are continuously extracted from the CNT forest by pinching a part of the CNTs of the CNT forest and pulling the CNTs away from the CNT forest. A structure having a structure in which a plurality of CNTs are entangled with each other, which is formed by performing the operation in a manner similar to the operation of manufacturing a yarn from fibers according to the related art, also referred to as “spinning”.

  Since CNT has a specific structure of having an outer surface made of graphene, application in various fields as a functional material and a structural material is expected. Specifically, CNTs have high mechanical strength, are light, have good electric conduction properties, have good thermal properties such as heat resistance and thermal conductivity, have high chemical corrosion resistance, and have good field electron emission properties. It has such excellent characteristics. Therefore, applications of CNTs include lightweight high-strength wires, scanning probe microscope (SPM) probes, field emission display (FED) cold cathodes, conductive resins, high-strength resins, corrosion-resistant resins, abrasion-resistant resins, Highly lubricating resins, electrodes for secondary batteries and fuel cells, interlayer wiring materials for LSIs, biosensors, and the like have been considered.

  As one method of manufacturing a CNT forest, Patent Document 1 discloses a method in which a solid phase metal catalyst film is formed on a surface of a substrate in advance by sputtering or the like by depositing a thin film of a metal-based material. A substrate provided with a metal catalyst film is placed in a reaction furnace, catalyst particles serving as growth nuclei are formed on the substrate from the metal catalyst film, and a carbon source such as a hydrocarbon gas is supplied to the reaction furnace to form CNTs on the substrate. A method for forming a forest is disclosed. Hereinafter, a solid phase catalyst particle as a growth nucleus is formed on a substrate as described above, and a carbon source containing a hydrocarbon material is supplied to a reaction furnace provided with a substrate on which the solid phase catalyst particle is disposed. The method of supplying and producing a CNT forest is called a solid phase catalytic method.

JP 2004-107196 A

  In the above solid-phase catalyst method, when forming catalyst particles serving as growth nuclei from a metal catalyst film on a substrate, the metal catalyst film is heated to melt the material constituting the metal catalyst film on the substrate. The shape based on the obtained droplets becomes the shape of the catalyst particles. At the time of the heating, oxidation of the material constituting the metal catalyst film inevitably occurs, so that an operation of reducing this oxide to catalyst particles is required. Specifically, a reducing gas such as an inert gas or a hydrogen gas is often supplied to the reactor.

  As described above, the solid-phase catalyst method is generally performed in three steps: formation of a metal catalyst layer, formation of catalyst particles including a reduction process, and growth of a CNT forest by supplying a carbon source. .

  An object of the present invention is to provide a method for more efficiently producing a CNT forest by a solid phase catalytic method. It is another object of the present invention to provide a spinning source member including the CNT forest manufactured by the above manufacturing method, a structure obtained from the spinning source member, and a composite structure including such a structure.

The present invention provided to solve the above problems is as follows.
(1) A liquid composition containing a metal element-containing compound is converted into a mist, and the obtained mist of the liquid composition is supplied into a reaction chamber heated to a predetermined temperature, and is contained in the mist of the liquid composition. Forming a metal-based solid-phase catalyst in the reaction chamber from the metal-element-containing compound to be formed, and arranging the metal-based solid-phase catalyst on a growth base surface of a substrate located in the reaction chamber. Supplying a carbon source into the reaction chamber, growing carbon nanotubes from the metal-based solid-phase catalyst on the growth base surface, and forming a carbon nanotube forest on the substrate. A method for producing a spinning source member including a carbon nanotube forest, wherein in the growing step, a gas phase co-catalyst is supplied into the reaction chamber, and the gas phase co-catalyst is a halo. The halogen-containing material is supplied into the reaction chamber at the same time as the supply of the carbon source or after the supply of the carbon source is started, and the supply amount of the halogen-containing material is The gas phase co-catalyst contains a reducing substance, and the reducing substance is selected from the group consisting of acetone, hydrogen and carbon monoxide. include one or more substances, the supply amount of the reducing agent, the spinning source member comprising a carbon nanotube forests, characterized in amounts der Rukoto to be less than 50 vol% 5 vol% or more of the supply amount of the carbon source Manufacturing method.

(2) The method for producing a spinning source member including the carbon nanotube forest according to (1), wherein the metal element-containing compound includes a metal element-containing coordination compound.

(3) The method for producing a spinning source member including the carbon nanotube forest according to (1) or (2), wherein the metal element-containing compound includes an iron group element as a metal element.

(4) The method for producing a spinning source member including the carbon nanotube forest according to any one of (1) to (3), wherein the liquid composition contains an organic solvent, and the organic solvent does not function as the carbon source.

(5) The method for producing a spinning source member including the carbon nanotube forest according to any one of (1) to (4), wherein the carbon nanotube forest is not formed on the growth base surface of the substrate in the catalyst disposing step.

(6) The spinning source member including the carbon nanotube forest according to any one of (1) to (5), wherein the mist of the liquid composition is formed by passing a gas through the liquid composition. Production method.

(7) The method for producing a spinning source member including the carbon nanotube forest according to any one of (1) to (5), wherein the mist of the liquid composition is mechanically performed.

(8) the growth substrate surface is made of at least one compound containing a method of manufacturing a spinning source member comprising a carbon nanotube forests according to any one of (1) to (7) of metal elements and metalloid elements.

(9) Production of a spinning source member including the carbon nanotube forest according to any one of (1) to (8) above, wherein the atmosphere of the reaction chamber when the metal-based solid phase catalyst is generated is an inert atmosphere. Method.

(10) The method for producing a spinning source member including the carbon nanotube forest according to any one of (1) to (9) , wherein the atmosphere in the reaction chamber in the growth step is 600 ° C. or higher.

  According to the method for producing a CNT forest according to the present invention, it is possible to form catalyst particles without substantially performing a reduction process. Therefore, the CNT forest can be manufactured efficiently. According to the present invention, there is also provided a spinning source member including the CNT forest efficiently manufactured by the above method, a structure obtained from the spinning source member, and a composite structure including the structure.

It is a figure showing roughly composition of a manufacturing device of a CNT forest concerning one embodiment of the present invention. FIG. 2 is a diagram schematically illustrating a configuration of a gas-phase catalyst supply device included in the manufacturing apparatus illustrated in FIG. 1. FIG. 2 is a diagram schematically illustrating a configuration of a gas-phase co-catalyst supply device included in the manufacturing apparatus illustrated in FIG. 1. It is an image which shows the result of having observed the CNT forest manufactured by the manufacturing method concerning one embodiment of the present invention from the direction where a side becomes in a field of view. It is an observation image of CNT which comprises the CNT forest manufactured by the manufacturing method concerning one embodiment of the present invention, and is an image showing the result of having observed CNT located near the height of half of the growth height of the CNT forest. It is. It is a graph which shows the outer diameter distribution of CNT which comprises the CNT forest (Experiment number 2) produced in the Example. It is an image which shows the state where the CNT entangled body was formed by drawing out (spinning) the CNT forest manufactured by the manufacturing method according to one embodiment of the present invention in a certain direction. 9 is an AFM image (plan view image) showing the result of taking out the substrate after the catalyst disposing step and measuring the surface on the growth base surface side by AFM. 9 is an image showing the AFM image of FIG. 8 as a perspective image. 9 is an observation image of a CNT forest according to Experiment No. 1. 9 is an observation image of a CNT forest according to Experiment No. 2. It is an observation image of the CNT forest according to Experiment No. 3. 9 is an observation image of a CNT forest according to Experiment No. 4. It is the observation image of CNT which comprises the CNT forest concerning Experiment No. 1, (a) CNT near the position farthest from the growth base surface, (b) CNT near the position at half the height of the growth height. (C) is an observation image showing the result of observing CNT at a position proximal to the growth base surface. It is the observation image of CNT which comprises the CNT forest which concerns on experiment number 2, Comprising: (a) CNT near the position most distal from the growth base surface, (b) CNT near the position of half height of the growth height (C) is an observation image showing the result of observing CNT at a position proximal to the growth base surface. It is the observation image of CNT which comprises the CNT forest concerning Experiment No. 3, (a) CNT near the position most distal from the growth base surface, (b) CNT near the position of half height of the growth height (C) is an observation image showing the result of observing CNT at a position proximal to the growth base surface. It is the observation image of CNT which comprises the CNT forest concerning Experiment No. 4, (a) CNT near the position most distal from the growth base surface, (b) CNT near the position at half height of the growth height (C) is an observation image showing the result of observing CNT at a position proximal to the growth base surface. It is a graph which shows the outer diameter distribution of CNT which comprises the CNT forest (experiment number 1) produced in the Example. It is a graph which shows the outer diameter distribution of CNT which comprises the CNT forest (Experiment number 3) produced in the Example. It is a graph which shows the outer diameter distribution of CNT which comprises the CNT forest (Experiment number 4) produced in the Example. It is a figure showing the result of having observed the growth base surface after exfoliating the CNT forest concerning experiment number 1. It is a figure showing the result of having observed the growth base surface after exfoliating the CNT forest concerning experiment number 2. It is a figure which shows the result of having observed the growth base surface after peeling the CNT forest concerning Experiment No. 3. It is a figure showing the result of having observed the growth base surface after exfoliating the CNT forest concerning experiment number 4. It is a figure showing the result of having spun CNT forest concerning experiment numbers 2 to 4.

  Hereinafter, embodiments of the present invention will be described.

1. CNT Forest Manufacturing Apparatus A CNT forest manufacturing apparatus according to one embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram schematically illustrating a configuration of a manufacturing apparatus that can be used in a method of manufacturing a CNT forest according to an embodiment of the present invention.

  As shown in FIG. 1, a CNT forest manufacturing apparatus 10 includes an electric furnace 12. The electric furnace 12 has a substantially cylindrical shape extending along a predetermined direction A (the direction in which the raw material gas flows). Inside the electric furnace 12, a reaction vessel tube 14, which is a reaction chamber having a growth region where a CNT is formed, is passed. The reaction vessel tube 14 is a substantially cylindrical member made of a heat-resistant material such as quartz, has an outer diameter smaller than that of the electric furnace 12, and extends along a predetermined direction A. In FIG. 1, a substrate 28 having a growth base surface on which a CNT forest grows is disposed in a growth region of the reaction vessel tube 14. That is, the growth region in the CNT forest manufacturing apparatus 10 includes a region where the substrate 28 is arranged in the reaction vessel tube 14.

  The position where the substrate is arranged in the growth region is not limited. The CNT forest may be arranged at a position where the CNT forest can be appropriately grown in consideration of the shape of the reaction vessel tube 14, the arrangement of the heater 16, the exhaust capacity, the amount of the substance supplied into the reaction vessel pipe 14, and the like. .

  The electric furnace 12 includes a heater 16 and a thermocouple 18. In the manufacturing apparatus 10 of the CNT forest, the temperature adjusting device includes a heater 16 and a thermocouple 18. The heater 16 is provided in a certain area of the reaction vessel tube 14 in the predetermined direction A (in other words, a certain area in the axial direction of the substantially cylindrical reaction vessel pipe 14, also referred to as a “heating area”). It is disposed so as to surround it, and generates heat for raising the temperature of the atmosphere in the heating vessel of the reaction vessel tube 14. The thermocouple 18 is disposed inside the electric furnace 12 near the heating region of the reaction vessel tube 14 and can output an electric signal indicating a temperature related to the temperature of the atmosphere in the heating vessel of the reaction vessel tube 14. The heater 16 and the thermocouple 18 are electrically connected to the control device 20.

  The supply device 22 is connected to the upstream side of the reaction vessel tube 14 in the predetermined direction A (one end on the left side in FIG. 1). The supply device 22 includes a source gas supply device 30, a catalyst raw material supply device 31, a gas phase co-catalyst supply device 32, and an auxiliary gas supply device 33. The supply device 22 is electrically connected to the control device 20, and is also electrically connected to each supply device included in the supply device 22.

  The source gas supply device 30 supplies a carbon compound (for example, a hydrocarbon such as acetylene) serving as a source of CNT constituting the CNT forest, that is, a source gas containing a carbon source to the inside of the reaction vessel tube 14 (particularly, a growth region). be able to. The supply flow rate of the source gas from the source gas supply device 30 can be adjusted using a known flow rate adjusting device such as a mass flow.

  The catalyst raw material supply device 31 applies minute droplets (catalyst supply mist) M of the catalyst supply liquid L obtained by atomizing the catalyst supply liquid L contained in the catalyst raw material supply device 31 to the reaction vessel tube 14. Can be supplied internally. Since the catalyst supply mist M contains the metal element-containing compound contained in the liquid L, the catalyst material supply device 31 can supply the metal element-containing compound to the inside of the reaction vessel tube 14 (particularly to the growth region). it can.

  As shown in FIG. 2, the catalyst raw material supply device 31 has a unit structure. That is, the catalyst raw material supply device 31 sprays the catalyst supply liquid L in the supply unit chamber 31A and the supply unit chamber 31A that can accommodate the catalyst supply liquid L made of the liquid composition containing the metal element-containing compound. It is provided with an atomizing device 31B for making the atomization. In FIG. 2, the atomizing device 31B includes a water bath 31B1 and an ultrasonic vibration generator 31B2 attached thereto.

  The catalyst raw material supply device 31 can discharge the catalyst supply mist M in the supply unit chamber 31A and the gas supply device 31C for transporting the catalyst supply mist M to the outside of the supply unit chamber 31A. Discharge device 31D is provided. In the supply unit chamber 31A, the catalyst supply mist M generated by the atomization device 31B is transported by a gas (an inert gas such as argon is supplied) supplied from the gas supply device 31C. It is supplied from the discharge device 31D into the reaction vessel tube 14. The gas supply device 31C and the discharge device 31D may include means for adjusting the amount of the substance passing through each of them. The catalyst raw material supply device 31 may have a mechanism for additionally supplying the catalyst supply liquid L, or may have a mechanism for controlling the pressure in the supply unit chamber 31A.

  The gas-phase co-catalyst supply device 32 can supply the gas-phase co-catalyst to the inside of the reaction vessel tube 14 (particularly to the growth region). The gas phase promoter will be described later. The supply flow rate of the gas-phase co-catalyst from the gas-phase co-catalyst supply device 32 can be adjusted using a known flow control device such as a mass flow. The gas-phase co-catalyst supply device 32 may be capable of supplying a plurality of gas-phase co-catalysts. For example, as shown in FIG. 3, the gas-phase co-catalyst supply device 32 includes a plurality of supply devices such as a first gas-phase co-catalyst supply device 32a, a second gas-phase co-catalyst supply device 32b,. May be.

  The auxiliary gas supply device 33 includes a gas other than the above-described raw material gas, the catalyst supply mist M, and the gas-phase cocatalyst, for example, an inert gas such as argon (this gas is generically referred to as “auxiliary gas” in this specification). It can be supplied to the inside of the reaction vessel tube 14 (especially the growth area). The supply flow rate of the auxiliary gas from the auxiliary gas supply device 33 can be adjusted using a known flow rate adjusting device such as a mass flow.

  A pressure regulating valve 23 and an exhaust device 24 are connected to the other end on the downstream side (the right side in FIG. 1) of the reaction vessel tube 14 in the predetermined direction A. The pressure adjusting valve 23 can adjust the pressure in the reaction vessel tube 14 by changing the degree of opening and closing of the valve. The exhaust device 24 evacuates the inside of the reaction vessel tube 14. The specific type of the exhaust device 24 is not particularly limited, and a rotary pump, an oil diffusion pump, a mechanical booster, a turbo molecular pump, a cryopump, or the like can be used alone or in combination. The pressure adjustment valve 23 and the exhaust device 24 are electrically connected to the control device 20. A pressure gauge 13 for measuring the internal pressure is provided inside the reaction vessel tube 14. The pressure gauge 13 is electrically connected to the control device 20 and can output an electric signal indicating the pressure inside the reaction vessel tube 14 to the control device 20.

  The control device 20 is electrically connected to the heater 16, the thermocouple 18, the supply device 22, the pressure gauge 13, the pressure regulating valve 23, and the exhaust device 24 as described above, and outputs the electric signals output from these devices and the like. It controls the operation of these devices and the like based on the input and the input electric signal. Hereinafter, a specific operation of the control device 20 will be exemplified.

  The control device 20 inputs an electric signal related to the internal temperature of the reaction vessel tube 14 output from the thermocouple 18 and outputs a control signal related to the operation of the heater 16 determined based on the electric signal to the heater 16. can do. The heater 16 that has received the control signal from the control device performs an operation of increasing or decreasing the amount of generated heat based on the control signal, and changes the internal temperature of the heating region of the reaction vessel tube 14.

  The control device 20 receives an electric signal related to the internal pressure of the heating region of the reaction vessel tube 14 output from the pressure gauge 13 and operates the pressure regulating valve 23 and the exhaust device 24 determined based on the electric signal. A control signal can be output to the pressure regulating valve 23 and the exhaust device 24. The pressure adjusting valve 23 and the exhaust device 24 to which the control signal from the control device 20 is input change the opening degree of the pressure adjusting valve 23 or change the exhaust capability of the exhaust device 24 based on the control signal. And so on.

  The control device 20 can output a control signal for controlling the operation of each device or the like to each device according to a preset time table. For example, the control signal for determining the start and stop of the material supply from each of the raw material gas supply device 30, the catalyst raw material supply device 31, the gas phase co-catalyst supply device 32, and the auxiliary gas supply device 33 included in the supply device 22 and the supply flow rate is determined. It can be output to the supply device 22. The supply device 22 that has received the control signal operates each supply device in accordance with the control signal to start or stop supplying each substance such as a raw material gas into the reaction vessel tube 14.

  The control device 20 can control the operation of each part constituting the catalyst raw material supply device 31. That is, the control device 20 can output a control signal relating to the operation of the atomizing device 31B provided in the catalyst raw material supply device 31. The atomizing device 31B that has received the control signal can start or stop atomizing the catalyst supply liquid L in the supply unit chamber 31A according to the control signal. The control device 20 can output a control signal related to the operation of the gas supply device 31C. The gas supply device 31C that has received the control signal changes the gas supply amount into the supply unit chamber 31A according to the control signal. The control device 20 can output a control signal related to the operation of the discharging device 31D. The discharge device 31D to which the control signal has been input adjusts the timing and amount of supplying the catalyst supply mist M outside the supply unit chamber 31A, that is, in the reaction vessel tube 14 in FIG. 1 according to the control signal. Can be. When the catalyst raw material supply device 31 includes an additional liquid supply system and an exhaust system as described above, the control device 20 can output control signals related to these operations.

2. Method for Manufacturing CNT Forest A method for manufacturing a CNT forest according to an embodiment of the present invention will be described. The method for manufacturing a CNT forest according to the present embodiment includes a catalyst placement step and a growth step. In the following description, a case where the manufacturing is performed using the manufacturing apparatus 10 will be described as a specific example.

(1) Catalyst Arrangement Step In the method for producing a CNT forest according to the present embodiment, as a catalyst arrangement step, a liquid composition (catalyst supply liquid L) containing a metal element-containing compound is converted into a mist to obtain a liquid. A mist of the composition (catalyst supply mist M) is supplied into a reaction chamber (reaction vessel tube 14) heated to a predetermined temperature, and a metal element contained in the mist of the liquid composition (catalyst supply mist M) A metal-based solid catalyst is generated in the reaction chamber (reaction vessel tube 14) from the contained compound, and the metal-based solid catalyst is deposited on the growth base surface of the substrate 28 located in the reaction chamber (reaction vessel tube 14). Deploy.

  The specific configuration of the substrate 28 is not limited. The shape is arbitrary, and may be a simple shape such as a flat plate or a cylinder, or may have a three-dimensional shape provided with complicated irregularities. Further, the entire surface of the substrate 28 may be a growth base surface, or only a part of the surface of the substrate 28 may be a growth base surface and other portions may not be a growth base surface, that is, a so-called patterned state. Is also good.

  The material constituting the growth base surface is not limited as long as the CNT forest can be grown. As a material constituting the growth base surface, a compound containing at least one of a metal element such as aluminum and a metalloid element such as silicon is exemplified. Specific examples thereof include oxides of silicon, oxides of aluminum, nitrides of silicon, nitrides of aluminum, and composite compounds thereof. The material forming the growth base surface may contain a transition metal element such as Fe or Ni, or may contain a nonmetal element such as boron or carbon.

  The material forming the growth base surface may be the same as or different from the material forming the substrate 28. As a specific example, when the material forming the substrate 28 is made of quartz and the material forming the growth base surface is also made of quartz, or the material forming the substrate 28 is made of a silicon substrate mainly composed of silicon and the growth base surface is formed of quartz. The case where the constituent material is made of the oxide film is exemplified.

  In the catalyst disposing step, the catalyst supply mist M is supplied into the reaction vessel tube 14. When a CNT forest is manufactured using the manufacturing apparatus 10, the catalyst supply mist M can be generated from the catalyst supply liquid L by using the catalyst raw material supply apparatus 31. In the catalyst raw material supply device 31, mist is formed using an ultrasonic vibration generator. That is, the mist of the catalyst supply liquid L is of a mechanical type. The method for forming the mist of the catalyst supply liquid L is not limited to this. It may be performed by passing a gas through the catalyst supply liquid L (bubbling).

  The catalyst supply mist M contains a metal element-containing compound, and a metal solid phase catalyst is formed from the metal element-containing compound. The metal element contained in the metal element-containing compound is not limited as long as it is an element constituting the catalyst material of the CNT forest. Preferred examples include iron group elements such as Fe, Ni, and Co. In addition, Mo and the like are also exemplified as the metal elements contained in the metal element-containing compound.

  The composition of the metal element-containing compound is not limited as long as a metal-based solid catalyst can be formed. A preferred example is a coordination compound containing a metal element. Specific examples of the metal element-containing coordination compound include metallocene compounds such as ferrocene, nickelocene, and cobaltene, carbonyl complexes such as iron carbonyl complexes, and iron-methanol complexes.

  By supplying the catalyst supply liquid L into the reaction vessel tube 14 as the catalyst supply mist M, various kinds of metal element-containing compounds can be easily and chemically stabilized in the reaction vessel tube 14. It is possible to do.

  The solvent contained in the catalyst supply liquid L is not limited as long as it can dissolve the metal element-containing compound. The catalyst supply liquid L may contain an organic compound as a solvent. Examples of such a solvent include alcohols such as ethanol and methanol. Such an organic compound as a solvent preferably does not function as a carbon source for growing carbon nanotubes. That is, it is preferable that the CNT forest is grown only in the growth step without forming the CNT forest on the growth base surface of the substrate 28 in the catalyst disposing step. By doing so, the controllability of the process can be improved.

  It is considered that the solvent of the catalyst supply mist M supplied into the reaction vessel tube 14 is quickly vaporized, and the fine metal element-containing compound is suspended in the reaction vessel tube 14. A metal-based solid catalyst is formed from the metal element-containing compound. When the metal element-containing compound is ferrocene, it is considered that iron atoms are generated from ferrocene, and the iron atoms are clustered, deposited on the growth base surface of the substrate 28, and arranged as a metal-based solid catalyst.

  The atmosphere in the reaction vessel tube 14 in the catalyst arrangement step, specifically, the atmosphere in the growth region where the substrate 28 is arranged is preferably an inert atmosphere. By using an inert atmosphere, the metal-based solid phase catalyst disposed in the catalyst disposing step becomes difficult to be oxidized, and the growth of the CNT forest can be started stably in the growing step.

The pressure of the atmosphere in the reaction vessel tube 14 in the catalyst disposing step is not particularly limited. Atmospheric pressure (about 1.0 × 10 ⁵ Pa), negative pressure, or positive pressure may be used. When the inside of the reaction vessel tube 14 is set to a negative pressure atmosphere in the growth step, it is preferable to shorten the transition time between steps by setting the atmosphere to a negative pressure also in the catalyst disposing step. When the inside of the reaction vessel tube 14 is set to a negative pressure atmosphere in the catalyst disposing step, the specific total pressure of the atmosphere is not particularly limited. As an example, it may be set to 1 × 10 ⁻² Pa or more and 1 × 10 ⁵ Pa or less.

  The temperature of the atmosphere in the reaction vessel tube 14 in the catalyst disposing step is not particularly limited. It may be at room temperature (about 25 ° C.), may be heated, or may be cooled. Since the atmosphere in the reaction vessel tube 14 is heated, the metal-based solid phase catalyst may be easily arranged on the growth base surface in some cases. As described later, since the growth region of the reaction vessel tube 14 is preferably heated in the growth process, the growth region is also heated in the catalyst placement process to shorten the transition time between steps. It may be preferable.

(2) Growth Step In the growth step, a carbon source is supplied into the reaction chamber (reaction vessel tube 14), and carbon nanotubes are grown from the metal-based solid catalyst on the growth base surface of the substrate 28. To form a CNT forest.

The type of the carbon source is not particularly limited, but usually, a hydrocarbon material is used, and acetylene is a specific example. The method for causing the carbon source to be present in the reaction vessel tube 14 (particularly in the growth region) is not particularly limited. As in the above-described manufacturing apparatus 10, the carbon source may be provided by supplying a carbon source from the raw material gas supply apparatus 30, or a material capable of generating the carbon source may be provided in the reaction vessel tube 14 in advance. Alternatively, the growth step may be started by generating a carbon source from the material and diffusing it into the reaction vessel tube 14. When supplying the carbon source from the raw material gas supply device 30, it is preferable to control the supply flow rate of the carbon source to the inside of the reaction vessel tube 14 using a flow rate adjusting device. Usually, the supply flow rate is expressed in units of sccm, and 1 sccm means a flow rate of 1 ml per minute for a gas converted into an environment of 273 K and 1.01 × 10 ⁵ Pa. In the case of the manufacturing apparatus 10 having the configuration shown in FIG. 1, the flow rate of the gas supplied into the reaction vessel tube 14 is based on the inner diameter of the reaction vessel pipe 14, the pressure measured by the pressure gauge 13, and the like. Is set. When the pressure of the pressure gauge 13 is 1 × 10 ² Pa or more and 1 × 10 ⁴ Pa or less, a preferable supply flow rate of the acetylene-containing carbon source is 10 sccm or more and 1000 sccm or less, and in this case, 20 sccm or more and 500 sccm or less. More preferably, it is more preferably 50 sccm or more and 300 sccm or less.

  In the present specification, the “gas-phase co-catalyst” has a function of promoting the growth of a CNT forest in a growth step (hereinafter, also referred to as a “growth promoting function”). A substance that has a function of improving the spinnability of a member including a forest (hereinafter, also referred to as a “spinnability improving function”) and is supplied in a gaseous state into the reaction vessel tube 14. The details of the growth promoting function are not particularly limited. The specific composition of the gas-phase co-catalyst is not particularly limited as long as it fulfills the above-mentioned growth promoting function and preferably also the function of improving spinnability.

As an example of the gas phase promoter, a halogen-containing substance that is a substance containing a halogen element can be given. Specific examples of the halogen-containing substance include chlorine (Cl ₂ ), bromine (Br ₂ ), hydrogen chloride (HCl), and hydrogen bromide (HBr). When a halogen-containing substance is used as the gas-phase cocatalyst, the halogen-containing substance is preferably supplied into the reaction chamber (reaction vessel tube 14) simultaneously with the supply of the carbon source or after the start of the supply of the carbon source. By supplying the halogen-containing substance in this manner, the possibility that the metal solid phase catalyst on the substrate 28 is halogenated and deactivated can be reduced.

  When the halogen-containing substance is supplied, the supply amount of the halogen-containing substance is preferably from 0.05% by volume to 5% by volume of the supply amount of the carbon source, and is preferably from 0.1% by volume to 3% by volume. The amount is more preferably not more than 0.2% by volume, particularly preferably not less than 0.2% by volume and not more than 1% by volume.

  Another example of the gas phase promoter is a reducing substance. Specific examples of the reducing substance include acetone, hydrogen, and carbon monoxide, and the reducing substance preferably includes one or more substances selected from the group consisting of these substances.

  When the reducing substance is supplied, the supply amount of the reducing substance is preferably an amount of 5% by volume or more and 50% by volume or less of the supply amount of the carbon source, and is preferably 10% by volume or more and 30% by volume or less. It is more preferable that the amount be as follows.

  The gas-phase co-catalyst can be supplied using the gas-phase co-catalyst supply device 32. When supplying the gas-phase co-catalyst into the reaction vessel tube 14, the gas-phase co-catalyst may be supplied alone, or may be supplied together with another gas (an inert gas is exemplified).

  The supply timing of the gas-phase co-catalyst, for example, the relationship with the supply timing of the carbon source is appropriately set according to the function of the gas-phase co-catalyst. When the gas phase promoter contains a halogen-containing substance, the halogen-containing substance is preferably supplied into the reaction chamber (reaction vessel tube 14) simultaneously with the supply of the carbon source or after the supply of the carbon source is started. When the halogen-containing substance is supplied before the carbon source, there is a concern that the metal-based solid catalyst may be affected by the halogen-containing substance and the function as a catalyst may be reduced.

The total pressure of the atmosphere in the reaction vessel tube 14 in the growth step is not particularly limited. Atmospheric pressure (about 1.0 × 10 ⁵ Pa), negative pressure, or positive pressure may be used. What is necessary is just to set suitably considering the composition (partial pressure ratio) of the substance which exists in the reaction vessel tube 14, etc. If a specific example of the pressure range when the atmosphere inside the heating region in the reaction vessel tube 14 is set to a negative pressure is 1 × 10 ¹ Pa or more and 1 × 10 ⁴ Pa or less, and 2 × 10 ¹ Pa or more 5 It is preferably set to × 10 ³ Pa or less, more preferably 5 × 10 ¹ Pa to 2 × 10 ³ Pa, particularly preferably 1 × 10 ² Pa to 1 × 10 ³ Pa.

  In the growth step, the temperature of the growth region of the reaction vessel tube 14 is controlled by using a carbon source to grow the substrate 28 under the condition that an appropriate amount of the metal-based solid catalyst and the optional gas-phase cocatalyst are present in the growth region. There is no particular limitation as long as a CNT forest can be formed on the base surface.

  The temperature of the growth base surface in the growth step may be controlled by adjusting the temperature of the growth region of the reaction vessel tube 14. The temperature of the growth base surface of the substrate 28 during the growth step is preferably heated to 600 ° C. or higher. When the temperature of the growth base surface of the substrate 28 is equal to or higher than 600 ° C., the interaction between the gaseous co-catalyst and the carbon source, which is used as necessary, easily occurs on the growth base surface, CNT forest is easy to grow. From the viewpoint of making this interaction more likely to occur, the temperature of the growth base during the growth step is preferably heated to 650 ° C. or higher, more preferably 700 ° C. or higher, and more preferably 750 ° C. or higher. It is particularly preferred that it is heated. The upper limit of the temperature of the growth base surface of the substrate 28 during the growth process is not particularly limited, but if it is excessively high, the material forming the growth base surface or the material forming the substrate 28 (these may be the same). ) May lack stability as a solid, so it is preferable to set the upper limit in consideration of the melting points and sublimation temperatures of these materials. Considering the load on the reaction vessel tube, the upper limit temperature of the substrate 28 is preferably set to about 1200 ° C.

3. CNT forest An example of a CNT forest manufactured by the manufacturing method according to one embodiment of the present invention is such that a plurality of CNTs are fixed in a certain direction (along the normal to the growth base plane) as shown in FIGS. Direction). When the outer diameters of a plurality of CNTs in this portion are measured and their distribution is determined, as shown in FIG. 6, the outer diameters of the CNTs constituting the CNT forest are mostly in the range of 5 to 30 nm. . By observing the CNTs constituting the CNT forest with an electron microscope or the like, the outer diameter of the CNTs can be measured from the obtained observation image.

  The CNT forest manufactured by the manufacturing method according to one embodiment of the present invention can have spinnability. Specifically, a structure (CNT entangled body) including a plurality of CNTs entangled with each other is obtained by pinching CNTs constituting the CNT forest and extracting (spinning) the CNTs away from the CNT forest. Can be. FIG. 7 is an image showing a state in which the CNT entangled body B is formed by drawing out (spinning) the CNT forest F manufactured by the manufacturing method according to the embodiment of the present invention in the direction S. The CNTs constituting the CNT entangled body are entangled with each other to form a connected body while being oriented in a direction (spinning direction) drawn from the CNT forest. In the present specification, a member including a CNT forest and capable of forming a CNT entangled body is also referred to as a “spinning source member”.

4. CNT entangled body The CNT entangled body obtained from the spinning source member can have various shapes. A specific example is a linear shape, and another example is a web shape. The linear CNT entangled body can be handled in the same manner as a fiber if twisted when the spinning source member is pulled out to obtain the same, and can also be used as electric wiring. Further, the web-shaped CNT entangled body can be handled as it is in the same manner as a nonwoven fabric.

  The length of the CNT entangled body in the spinning direction is not particularly limited, and may be appropriately set according to the application. Generally, if the spinning length is 2 mm or more, the CNT entangled body can be applied to a part level such as a contact portion and an electrode. In addition, the degree of orientation of the CNTs constituting the linear CNT entangled body can be arbitrarily controlled by changing a spinning method (specific examples include a degree of twisting) from the spinning source member. Can be. Therefore, by changing the spinning method from the spinning source member, it is possible to manufacture CNT entangled bodies having different mechanical properties and electrical properties.

  If the degree of entanglement is reduced, the CNT entangled body becomes thinner in the case of a linear shape and thinner in the case of a web shape. If the degree increases, it becomes difficult to visually confirm the CNT entangled body, and at this time, the CNT entangled body can be used as a transparent fiber, a transparent wiring, or a transparent web (a transparent sheet-like member).

  The CNT entangled body may be made of only CNT or a composite structure with another material. As described above, since the CNT entangled body has a structure in which a plurality of CNTs are intertwined with each other, voids exist between the intertwined CNTs as in the case of the plurality of fibers constituting the nonwoven fabric. I do. Powder (inorganic particles such as metal fine particles and silica, and organic particles such as an ethylene polymer) is introduced into the void portion, or the liquid is impregnated with the powder so that the powder can be easily impregnated. A composite structure can be formed.

  Further, the surface of CNT constituting the CNT entangled body may be modified. Since the outer surface of CNT is composed of graphene, the CNT entangled body is hydrophobic as it is, but the CNT entangled body is made hydrophilic by performing a hydrophilic treatment on the surface of the CNT constituting the CNT entangled body. can do. An example of such a means for making hydrophilic is a plating treatment. In this case, the obtained CNT entangled body becomes a composite structure of CNT and plated metal.

  The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  Hereinafter, the present invention will be described more specifically with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

(Example 1)
(1) Preparation of Catalyst Supply Liquid L Ferrocene as a metal element-containing coordination compound, which is a kind of metal element-containing compound, is dissolved in ethanol, and ethanol having a ferrocene concentration of 10 g / L (1.3% by mass) is prepared. The solution was obtained as a catalyst supply liquid L.

(2) Production of Catalyst Arrangement Step A CNT forest was produced using a CNT forest production apparatus having the structure shown in FIG. A heat-resistant dish (not shown) containing the catalyst supply liquid L therein was placed on the inner surface inside the reaction vessel tube.

A silicon substrate (10 mm × 5 mm × 0.6 mm in thickness) having a thermal oxide film (thickness: 400 nm) was prepared as a substrate. Therefore, in this example, the material constituting the growth base surface was SiO ₂ . With the substrate placed on a boat made of quartz, the substrate was placed together with the boat in a reaction vessel tube as a reaction chamber.

The inside of the reaction vessel tube was evacuated to 300 Torr (40 kPa) using an exhaust device. Subsequently, while maintaining the pressure in the reaction vessel tube at 300 Torr (40 kPa), the inside of the reaction vessel tube was heated to 820 ° C. (1.09 × 10 ³ K) using a heater, and the temperature of the heat-resistant dish and the substrate was reduced. The temperature was about 820 ° C. (1.09 × 10 ³ K).

  The catalyst supply liquid L is put into the supply unit chamber of the catalyst raw material supply device having the structure shown in FIG. 2, and the atomizing device (including the ultrasonic vibration generator) is operated to supply the catalyst. Mist M was generated. Argon was supplied from the gas supply device at 500 sccm, and a valve as a discharge device was opened for 1 minute to supply the catalyst supply mist M into the reaction chamber. As a result, a metal-based solid-phase catalyst was formed on the growth base surface of the substrate.

  The formation of the metal-based solid catalyst was separately confirmed as follows. After completing the above-described catalyst arrangement step, the inside of the reaction chamber was returned to room temperature, and then the pressure in the reaction chamber was set to atmospheric pressure, and the substrate was taken out of the reaction chamber. The surface on the growth base surface side of the substrate taken out was measured by AFM (measurement size: 0.5 μm × 0.5 μm). An AFM image was obtained based on the measurement data (FIGS. 8 and 9). As shown in FIGS. 8 and 9, a substance having a diameter of several tens of nm and a height of several nm was arranged on the growth base surface so as to cover the growth base surface. The AFM image is obtained by measuring the surface on which the metal-based solid catalyst formed by performing a general method of manufacturing a metal-based solid catalyst comprising iron sputtering, hydrogen reduction, and heating by AFM in the atmosphere. It was equivalent to the AFM image obtained. Therefore, it was confirmed from the AFM images shown in FIGS. 8 and 9 that the metal-based solid-phase catalyst was appropriately arranged on the growth base surface by the above-described catalyst arrangement step.

(3) Growth Step With the temperature inside the reaction vessel tube set to 820 ° C. (1.09 × 10 ³ K), the pressure inside the reaction vessel tube was reduced to 3 Torr (400 Pa). While maintaining the pressure in the reaction vessel tube at 3 Torr (400 Pa), as shown in Table 1 (the unit of the numerical value in Table 1 is sccm), acetylene as a source gas was supplied from the source gas supply device at 160 sccm as shown in Table 1. The flow rate, the amount of argon as a kind of auxiliary gas from the auxiliary gas supply device to the flow rate of 11 to 20 sccm, and the gas phase co-catalyst supply device of acetone as a reducing substance, which is a type of gas-phase co-catalyst, 20 sccm. The flow rate and the amount of chlorine (Cl ₂ ) as a halogen-containing substance, which is another kind of the gas phase promoter, are supplied from the gas phase promoter supply device into the reaction vessel tube for 20 minutes at a flow rate of 0 to 0.9 sccm. Then, a growth step was performed (Experiment Nos. 1 to 4). Chlorine (Cl ₂ ) was supplied with 9 times the amount of argon, and the total flow of gas supplied to the reaction chamber was 200 sccm in each case, as shown in Table 1.

  As a result, as shown in FIGS. 10 to 17, a CNT forest was obtained on the substrate in any of Experiment Nos. 1 to 4. 10 to 13 are observation images obtained at a magnification that allows confirmation of the composite structure of the CNT forest. FIGS. 14 to 17 show (a) CNT in the vicinity of the most distal position from the growth base surface, and (b) a position at half the height of the growth height, in order to confirm the growth state of CNTs constituting the CNT forest. It is an observation image which shows the result of having observed the CNT of the vicinity and the CNT of the position near the growth base surface (c).

  The thickness (outer diameter) of the CNTs constituting each CNT forest was measured to obtain a frequency distribution. The results are shown in FIG. 6 (Experiment No. 2) and FIGS. 18 to 20 (Experiment Nos. 1, 3 and 4). From the obtained frequency distribution, the average outer diameter (unit: nm) of CNTs constituting the CNT forest according to each experiment number was determined. Table 2 shows the results.

  The CNT forest during the growth process was photographed with a camera, and the growth height (unit: mm / 20 minutes) and the growth rate (unit: μm / min) were determined from the photographed images. Table 2 shows the results.

With respect to the CNT forest according to each experiment number, the CNT forest was peeled from the growth base surface by moving the CNT forest in a direction parallel to the growth base surface by applying a thin blade near the interface with the growth base surface. When the growth base surface after peeling was observed, traces from which the CNTs came off could be confirmed as holes (FIGS. 21 to 24). The density of the pores was measured and defined as the density of CNT in the CNT forest (unit: 10 ¹⁰ cm ⁻² ). Table 2 shows the results.

  For each of the CNT forests according to Experiment Nos. 2 to 4, the CNTs were pulled out by pinching the ends (spun). FIG. 25 shows the result. It was confirmed that the CNT forests according to Experiment Nos. 2 and 3 had particularly good spinnability.

  For each CNT forest, the Raman spectrum of the CNT located at about half the height of the growth height was measured, and the G / D ratio was determined from the obtained Raman spectrum. Table 2 shows the results.

  The CNT entangled body obtained from the CNT forest manufactured by the method for manufacturing a CNT forest according to the present invention is suitably used, for example, as an electric wiring, a heating element, a strain sensor, a transparent electrode sheet, and the like.

10 CNT Forest Manufacturing Equipment 12 Electric Furnace 13 Pressure Gauge 14 Reaction Tube (Reaction Chamber)
16. Heater (part of temperature control device)
18 ... thermocouple (part of temperature control device)
20 control device 22 supply device 23 pressure regulating valve (part of pressure regulating device)
24 ... Exhaust device (part of pressure regulator)
28 substrate 30 source gas supply device 31 catalyst raw material supply device 32 gas phase co-catalyst supply device 32a first gas phase co-catalyst supply device 32b second gas phase co-catalyst supply device 33 auxiliary gas supply device 31A Supply unit chamber 31B Atomizer 31B1 Water bath 31B2 Ultrasonic vibration generator 31C Gas supply device 31D Discharge device

Claims (10)

A liquid composition containing a metal element-containing compound is mist-formed, and the obtained mist of the liquid composition is supplied into a reaction chamber heated to a predetermined temperature, and the mist of the liquid composition is contained in the mist. Generating a metal solid phase catalyst from the metal element-containing compound in the reaction chamber, on a growth base surface of a substrate located in the reaction chamber, a catalyst arrangement step of arranging the metal solid phase catalyst,
Supplying a carbon source into the reaction chamber, growing carbon nanotubes from the metal-based solid catalyst on the growth base surface, and forming a carbon nanotube forest on the substrate;
A method for producing a spinning source member comprising a carbon nanotube forest comprising (excluding a case where a sublimated catalyst and a carbon source undergo a gas phase reaction),
In the growing step, a gas phase co-catalyst is supplied into the reaction chamber,
The gas-phase co-catalyst contains a halogen-containing substance, and the halogen-containing substance is supplied into the reaction chamber at the same time as the supply of the carbon source or after the supply of the carbon source is started,
The supply amount of the halogen-containing substance is an amount that is 0.05% by volume or more and 0.375% by volume or less of the supply amount of the carbon source.
The gas-phase promoter includes a reducing substance,
The reducing substance includes at least one substance selected from the group consisting of acetone, hydrogen and carbon monoxide,
The method of manufacturing a spinning source member including a carbon nanotube forest, wherein the supply amount of the reducing substance is 5% by volume or more and 50% by volume or less of the supply amount of the carbon source.   The method according to claim 1, wherein the metal element-containing compound includes a metal element-containing coordination compound.   3. The method according to claim 1, wherein the metal element-containing compound includes an iron group element as a metal element. 4.   4. The method according to claim 1, wherein the liquid composition contains an organic solvent, and the organic solvent does not function as the carbon source. 5.   The method for producing a spinning source member including a carbon nanotube forest according to any one of claims 1 to 4, wherein a carbon nanotube forest is not formed on a growth base surface of the substrate in the catalyst disposing step.   The method for producing a spinning source member including a carbon nanotube forest according to any one of claims 1 to 5, wherein the mist of the liquid composition is formed by passing a gas through the liquid composition.   The method for producing a spinning source member including a carbon nanotube forest according to any one of claims 1 to 5, wherein the mist of the liquid composition is mechanically performed.   The method according to any one of claims 1 to 7, wherein the growth base surface is made of a compound containing at least one of a metal element and a metalloid element.   The method for producing a spinning source member including a carbon nanotube forest according to any one of claims 1 to 8, wherein an atmosphere in the reaction chamber when the metal-based solid catalyst is generated is an inert atmosphere.   The method for manufacturing a spinning source member including a carbon nanotube forest according to any one of claims 1 to 9, wherein the atmosphere in the reaction chamber in the growing step is at least 600 ° C.