JP2015063766A - Production method and the like of composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of a composite material by controlling a state of adhesion of CNTs in adhering the CNTs to a surface of a base material with multiple CNTs directly adhered thereto.SOLUTION: A production method has: a first step to prepare a composite material to which CNTs are directly adhered without any inclusion such as a dispersing agent as a base material; a second step to produce a second CNT dispersion in which CNTs are dispersed without containing any inclusion and in a state in which CNTs are easily coagulated, and to adjust a concentration of the CNT in the second CNT dispersion in the second and subsequent execution of third and fourth steps mentioned below; the third step to immerse the base material in the CNT dispersion; and the fourth step to pull up the base material from the CNT dispersion and to dry the base material. The third and fourth steps are executed at least once or more corresponding to the state of adhesion of the CNT to a surface of the base material, and in the second and subsequent execution of the third and fourth steps mentioned above, after returning to the second step and adjusting the concentration of the CNT in the second CNT dispersion, the second and subsequent execution are carried out.

Description

  The present invention relates to a method for producing a composite material in which carbon nanotubes (hereinafter abbreviated as CNT) are attached to the surface of a base material.

  In such a composite material, it is desirable that CNTs uniformly adhere to the surface of the base material to form a CNT network in order to exhibit the function as the composite material.

  In such a composite material, a base material is put into a solution in which CNTs are dispersed at a nano level (in the specification, it may be abbreviated as a CNT dispersion liquid), and the CNTs adhere to the surface of the base material in a network. After that, the base material is pulled up from the CNT dispersion and dried.

  However, since CNT aggregates irreversibly in the CNT dispersion due to van der Waals force, in order to form a CNT network by uniformly attaching CNT to the surface of the base material, a large amount of dispersant is added to the solution. Therefore, it is necessary to disperse CNTs by preventing aggregation of CNTs.

  In this dispersion, the CNT dispersion liquid is supplementarily irradiated with ultrasonic waves or stirred (see Patent Document 1). The dispersant is necessary for dispersing the CNT, and is generally used as an essential component in the manufacturing process of the composite material.

  In addition, in addition to the dispersant, an adhesive and other additives are added to the CNT dispersion in order to adhere the CNT to the surface of the base material.

  The composite material produced in this way has not only the function of the base material but also the electrical conductivity, thermal conductivity, mechanical strength, etc. derived from the CNT as a composite material due to the composite of CNT in the base material. There is expected.

JP 2010-59561 A

  In order to improve the performance of the composite material, such as electrical conductivity, thermal conductivity, mechanical strength, etc., the above-mentioned composite material is generally adhered to the surface of the base material by attaching CNT to the base material surface at a high concentration. It is possible to construct a CNT network at a high density.

  However, if a large amount of CNT is used and the CNT concentration is increased and a large amount of CNT is combined with the base material, the original function of the base material may be impaired. The electrical conductivity, thermal conductivity, mechanical strength, etc. of these materials do not reach the required level for practical use.

  The reason for this is thought to be that CNT dispersants and adhesives that adhere CNTs to the base material are inclusions that cause insulation or poor heat conduction. The adhesive is indispensable for uniformly attaching CNTs to the surface of the base material, and must be used.

  In view of the above, the present applicant has no inclusions such as a dispersant and an adhesive that are essential for the dispersion and adhesion of CNTs in the invention of Japanese Patent Application No. 2013-098905 (filed on May 8, 2013). However, while maintaining good dispersibility of CNTs, the amount of CNTs used in the base material can be reduced (low concentration) so that the original function of the base material can be expressed. We have already provided composite materials that satisfy the required level of practical use by exhibiting functions such as thermal conductivity, thermal conductivity, and mechanical strength.

  However, in the manufacturing method of the composite material (hereinafter referred to as the prior application invention) according to the above-mentioned applicant's application, the CNT is attached to the surface of the base material, that is, the CNT film attached to the surface of the base material. It was difficult to control the uniformity of thickness or the amount (concentration) of CNT attached to the entire surface of the base material.

  An object of the present invention is to provide a manufacturing method or the like for manufacturing a composite material by arbitrarily controlling the adhesion state of CNTs to the surface in the prior invention.

The method for producing a composite material according to the present invention includes:
A plurality of carbon nanotubes (hereinafter referred to as CNT) are directly contacted or directly connected without inclusions such as a dispersant to form a network, and the plurality of CNTs are directly attached to the surface without the inclusions. A first step of preparing a composite material as a base material;
Preparation of the second CNT dispersion liquid containing no inclusions and in which the CNTs are easily aggregated, and the second and subsequent steps of the third and fourth steps described later, the CNT concentration in the second CNT dispersion liquid A second step of preparation;
A third step of immersing the base material in the second CNT dispersion;
A fourth step of lifting the base material from the second CNT dispersion and drying it.
The third and fourth steps are performed at least once according to the adhesion state of the CNT to the surface of the base material, and the second and subsequent steps of the third and fourth steps are performed in the second step. Returning to step 2, after the CNT concentration in the second CNT dispersion is adjusted, the second and subsequent implementations are performed.

  According to the present invention, since the third and fourth steps are repeated until the CNT adheres to the surface of the base material in a predetermined state, a composite material in which the CNT adheres to the base material surface in a predetermined state is manufactured. can do.

  Note that the number of repetitions of the third and fourth steps and the time required for each step may be controlled until the CNT adheres to the surface of the base material in a predetermined state.

  The inclusions include a dispersant for dispersing CNT in the solution, an adhesive for adding the base material to the solution, and bonding the CNT to the base material surface, and other additives, Etc. can be illustrated.

  The inclusions include at least an insulating material such as a dispersant and an adhesive, and a material having poor heat conductivity.

  Furthermore, CNT is not limited to the kind.

The predetermined state includes the CNT film thickness uniformity with respect to the surface of the base material or the amount of CNT attached to the entire surface of the base material.
Preferably, the composite material used as the base material is one in which CNTs adhere to the carbon fiber surface.

  Preferably, the first step includes a first sub-step of dispersing the plurality of CNTs in a solution that does not contain an inclusion such as a dispersant, and applying predetermined energy to the solution. A second sub-step of producing a first CNT dispersion in which a reversible reaction state in which the plurality of CNTs are dispersed and aggregated is reversibly generated; and the first CNT dispersion in the reversible reaction state When the plurality of CNTs transition from the dispersed state to the aggregated state on the surface of the base material immersed in the base material, the plurality of CNTs are entangled with each other in a network form and directly contacted without inclusions. A third sub-process for directly connecting and directly adhering to the surface of the base material without inclusions, and performing the first sub-step to the third sub-step so that there is no inclusion on the surface Preparing a composite material in which the plurality of CNT is attached directly as the base material.

  Preferably, the second step includes a fourth sub-step in which the plurality of CNTs are put into a solution that does not contain an inclusion such as a dispersant, and a predetermined energy is given to the solution. A fifth sub-step for producing a reversible reaction state in which the state in which the plurality of CNTs are dispersed and the state in which the plurality of CNTs are aggregated is created; and stopping the application of the energy to the solution And a sixth sub-step of obtaining a 2CNT dispersion.

  In this case, it is preferable that the second step includes a seventh sub-step of adjusting the CNT concentration of the second CNT dispersion when the second and subsequent steps of the third and fourth steps are performed, In the third and fourth steps, when the second and subsequent steps are performed, the second CNT dispersion liquid in which the CNT concentration is adjusted in the seventh sub-step is used.

  Preferably, the predetermined energy is ultrasonic energy.

  According to the production method of the present invention, it is possible to produce a composite material to which CNTs adhere in a predetermined state.

It is process drawing of the manufacturing method which concerns on embodiment of this invention. (A) is a first CNT dispersion prepared in step (2), (b) is a small amount of a general CNT dispersion dropped on a silicon substrate, and dried in an oven at 400 ° C. for 1 hour. It is a SEM photograph of each CNT of time. (A) is a TEM (transmission electron microscope) photograph of CNT in the 1st CNT dispersion liquid manufactured at the process (2), (b) is a one part enlarged SEM photograph of (a). (A) is a schematic block diagram of a preform | base_material, (b) is a conceptual block diagram of the cross-section which expanded a part of preform | base_material of (a). It is a conceptual block diagram of the 2nd CNT dispersion liquid produced at the process (4). (A) is a photograph of a transparent container containing the second CNT dispersion prepared in step (4), and (b) is a state in which the CNTs of the CNT dispersion in the transparent container of (a) are dispersed. (C) is a photograph showing a state in which CNTs in the CNT dispersion liquid of (b) are aggregated. (A) is a process conceptual diagram for explaining the first implementation of the process (5) and the process (6), and (b) is used for explaining the second implementation of the process (5) and the process (6). Process conceptual diagram, (c) is a process conceptual diagram for explaining the third implementation of the process (5) and the process (6). It is a SEM photograph of carbon fiber which has not been processed anything. It is a SEM photograph of the base material manufactured by implementation of a process (3) from carbon fiber of Drawing 8A. It is a SEM photograph of the base material manufactured by the implementation of Step (5) and Step (6) (the first implementation for the base material of FIG. 8B) from the base material of FIG. 8B. It is the SEM photograph of the base material manufactured by the additional execution (execution 2nd with respect to the base material of FIG. 8B) of the process (5) and the process (6) from the base material of FIG. 8C. It is a SEM photograph of the base material manufactured by the additional execution (execution of the 3rd time to the base material of Drawing 8B) of Step (5) and Step (6) from the base material of Drawing 8D.

  Hereinafter, a method for manufacturing a composite material according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  The composite material according to the embodiment uses a material in which CNTs are attached to the surface of a carbon material, a resin material, a metal material, a ceramic material, or the like as a base material. In particular, in the embodiment, a composite material in which CNTs adhere to the carbon fiber surface is used as an example of a base material.

  FIG. 1 is a process diagram of a manufacturing method according to an embodiment of the present invention. The manufacturing method will be described with reference to FIG. This manufacturing method includes steps (1) to (6). Step (1) is a CNT manufacturing step, step (2) is a step of preparing a first CNT dispersion, step (3) is a step of preparing the base material, and step (4) is a second CNT dispersion step. Step (5) is a step of immersing the base material in the second CNT dispersion, and step (6) is a step of lifting the base material from the second CNT dispersion and drying. Each process will be described in turn below.

Step (1) ... CNT manufacturing step In step (1), CNTs are manufactured. This CNT is manufactured by, for example, a substrate growth thermal CVD method described in Japanese Patent Application Laid-Open No. 2007-126311. In the substrate growth thermal CVD method, a catalyst metal is formed on a silicon substrate, and the catalyst metal is atomized. Then, a hydrocarbon gas is brought into contact with the finely divided catalyst metal in a heated atmosphere. Thereby, CNT grows on the catalyst metal. The produced CNTs are used in the following steps. However, the production of CNTs is not limited to the substrate growth thermal CVD method, and other production methods such as an arc discharge method and a laser evaporation method may be used.

  The CNTs produced in this step (1) are not limited to the kind thereof, but for example, multi-walled CNTs having an average length of 0.1-50 μm and an average diameter of 30 nm or less are preferable. Moreover, if the average length of CNT is 0.1 μm or more, CNTs are entangled in a more preferable state in each step (3) and step (5) described later, and if the length is 50 μm or less. CNTs are more easily and evenly dispersed, and when the diameter is 30 nm or less, the flexibility of CNTs can be more utilized, and the CNT network can be formed more flexibly along the curvature of the base material surface. Further, the multilayer CNT preferably has a diameter of 20 nm or less.

Step (2) ... Production Step of First CNT Dispersion A first CNT dispersion in which CNTs are isolated and dispersed is produced from the CNT produced in step (1). The isolated dispersion refers to “a state in which CNTs are dispersed in the resin in a state where the CNTs are physically separated and not entangled one by one”. Here, “physically separated and not intertwined” means that a plurality of CNTs are isolated one by one without taking the form of agglomerated or aggregated into a lump or bundle by van der Waals force. Say that. In the first CNT dispersion, CNT is mixed in a solvent, and the dispersion of CNTs is made uniform by a homogenizer, high-pressure shear, an ultrasonic disperser, or the like. However, the first CNT dispersion is not charged with a dispersant or an adhesive.

  A small amount of the first CNT dispersion liquid produced in the above step (2) and a general CNT dispersion liquid in FIG. 2 (b) are dropped on the silicon substrate in FIG. The SEM photograph of each CNT when dried at 400 ° C. for 1 hour is shown.

  In the first CNT dispersion liquid, as is apparent from the SEM photograph of FIG. 2A, it can be seen that each CNT 18 is nano-dispersed and fibrous with a high aspect ratio.

  On the other hand, it can be seen that a general CNT dispersion is inappropriate for forming a network because the CNT 20 has a small aspect ratio, as is apparent from the SEM photograph of FIG. In addition, in FIG. 2B, a portion indicated by an arrow indicates a state where the CNTs 20 are aggregated without being isolated.

  3A and 3B show TEM (transmission electron microscope) photographs of the CNTs 21 in the first CNT dispersion produced in the above step (2). As shown in FIGS. 3 (a) and 3 (b), the CNTs 21 are all tubular and have a diameter of approximately 20 nm or less, and it is understood that the CNTs 21 are suitable for forming a uniform CNT network.

Step (3) ... Preparation Step of Base Material In this step (3), a machine such as shear or ultrasonic wave is immersed in the dispersion in the state where the carbon fiber bundle is immersed in the first CNT dispersion produced in step (2). A CNT network is locally unevenly distributed on the surface of carbon fiber while imparting energy.

  As described above, the first CNT dispersion does not contain inclusions such as a dispersant, a surfactant, an adhesive, and an additive.

  Ultrasonic energy is applied to the first CNT dispersion. By applying ultrasonic energy, a reversible reaction state in which a state in which CNTs are dispersed and a state in which they are aggregated is always generated in the first CNT dispersion liquid.

  Carbon fibers are immersed in the first CNT dispersion in this reversible reaction state. Then, also on the carbon fiber surface, a reversible reaction state occurs in which the CNT dispersion state and the aggregation state reversibly occur, and the CNT adheres to the carbon fiber surface when moving from the dispersion state to the aggregation state. When aggregating, van der Waals force acts on the CNT, and the CNT adheres to the carbon fiber surface by this van der Waals force.

  After that, when the carbon fiber is drawn out from the first CNT dispersion and dried, the composite material shown in FIGS. 4A and 4B formed by locally distributing the CNT network on the surface of the carbon fiber is used as a base material. 1 can be obtained.

  4A and 4B show a conceptual configuration of the base material 1. FIG. FIG. 4A is a schematic configuration diagram of the base material 1. FIG. 4B is a conceptual configuration diagram illustrating a cross-sectional configuration of a part of the base material of FIG.

  As shown in FIGS. 4A and 4B, the base material 1 is a composite material composed of a plurality of carbon fibers 3 and a plurality of CNTs 5 attached to the respective surfaces of the plurality of carbon fibers 3. ing. In the base material 1, the CNT 5 is in direct contact with or directly connected to the surface of the carbon fiber 3 to form a CNT network 7 and has no inclusion at the boundary with the surface of the carbon fiber 3. It is directly attached to the surface.

  The carbon fiber 3 is not particularly limited, but has a diameter of about 3 to 3 obtained by firing organic fibers derived from petroleum, coal, coal tar, etc., such as polyacrylonitrile, rayon and pitch, and organic fibers derived from wood and plant fibers. A 15 μm fiber can be exemplified.

  The inclusion is not particularly limited, and examples thereof include a dispersant containing a surfactant and an adhesive.

  As described above, since the base material 1 is in direct contact or directly connected with the CNTs 5 without inclusions, the electrical conductivity and thermal conductivity between the CNTs 5 in the CNT network 7 are good, Since the CNT network 7 is attached to the surface of the carbon fiber 3 without inclusions, it is difficult to peel off from the surface of the carbon fiber 3 and its mechanical strength is high.

  In the base material 1 thus prepared up to the step (3), the CNTs 5 adhering to the surface of the carbon fiber 3 are sparse and non-uniform in thickness, and the film thickness is thin.

Step (4) ... Production and Preparation Step of Second CNT Dispersion Next, in step (4), production of the second CNT dispersion for immersing the base material 1 produced in step (3), and steps described later (5) In order to immerse the base material after carrying out (6), the CNT concentration with respect to the produced second CNT dispersion is prepared.

  That is, ultrasonic energy is applied to the CNT solution to which CNT is administered. By applying this ultrasonic energy, the CNTs in the CNT solution become dispersed. During the application of ultrasonic energy, the CNT in the CNT solution is dispersed and agglomerated. In addition, this 2nd CNT dispersion liquid does not contain inclusions, such as a dispersing agent, surfactant, an adhesive agent, and an additive like a 1st CNT dispersion liquid. When the application of ultrasonic energy is stopped, the CNT solution is maintained in a CNT dispersion state, and the second CNT dispersion is produced. In the second CNT dispersion liquid thus produced, although CNTs are dispersed, when a mechanical vibration is applied, the second CNT dispersion liquid easily becomes an aggregated state from the dispersed state.

  Moreover, if the 2nd CNT dispersion liquid 9 is used for implementation of process (5) (6) mentioned later, the CNT density | concentration in the said 2nd CNT dispersion liquid 9 will fall. In addition, with the passage of time after the implementation of steps (5) and (6), CNT aggregation in the second CNT dispersion 9 starts, and the aggregation is saturated. Has fallen. Therefore, for the second and subsequent steps (5) and (6), prior to the execution, the process returns to step (3) to adjust the CNT concentration in the second CNT dispersion 9. In this case, since the CNTs are reduced by performing the steps (5) and (6), in order to add the CNTs, ultrasonic energy is applied again to control the CNTs in the dispersed state.

  FIG. 5 shows a conceptual configuration of the second CNT dispersion liquid 9. The CNTs 11 are evenly dispersed in the second CNT dispersion 9, but when mechanical vibration is applied, the CNTs 11 are easily aggregated from the dispersed state.

  FIG. 6A shows a photograph of the transparent container 12 in which the second CNT dispersion liquid prepared as described above is placed, and FIG. 6B shows a photograph of the second CNT dispersion liquid 9 in the transparent container 12. Indicates.

  As shown in this photograph, the second CNT dispersion 9 conceptually shown in FIG. 5 has no black portions indicating CNT aggregates, and it can be seen that the CNTs are uniformly dispersed.

  When mechanical vibration is applied to the transparent container 12, it can be seen that the CNTs in the second CNT dispersion 9 are aggregated to form an aggregate 10 as shown in FIG. Thus, the second CNT dispersion 9 can be produced in the step (4).

Steps (5), (6) ... Step of immersing and drying base material 1 in second CNT dispersion 9 In the embodiment, steps (5) and (6) are performed on base material 1 as shown in FIG. ,carry out. First, as shown in FIG. 7A, the base material 1 is immersed in the second CNT dispersion 9. In this immersed state, mechanical vibration is applied to the second CNT dispersion 9.

  Then, the CNTs 11 dispersed in the second CNT dispersion 9 are aggregated. At this time, the CNTs 11 are separated from the base material 1 by van der Waals force with the CNTs 13 on the surface of the base material 1. Adhere to the surface of the. In addition, the base material 1 initially immersed in the second CNT dispersion liquid 9 in the step (5) (first immersion) is referred to as a base material 1a. Then, in step (6), the base material 1a is pulled up from the second CNT dispersion 9 and dried with a dryer or the like not shown. Thus, the first step (5) and (6) for the base material is completed.

  Next, for the implementation of the second steps (5) and (6), the process returns to step (4) to adjust the CNT concentration in the second CNT dispersion 9. The reason for this is that, as described above, the second CNT dispersion 9 has a certain amount of CNT aggregation as time elapses from when the application of energy by ultrasonic waves is stopped. Although the CNTs adhere to the base material 1, the remaining CNTs start to aggregate in the second CNT dispersion liquid 9, and the second CNT dispersion liquid 9 is reached by the time when the second steps (5) and (6) are performed. Aggregation of CNT becomes saturated, and the ability of CNT to adhere to the base material decreases. Therefore, prior to the next second steps (5) and (6), return to step (4), add CNTs, apply ultrasonic energy, and adjust CNT dispersion and concentration. Do. Then, after the concentration adjustment, as shown in FIG. 7B, step (5) is performed on the base material 1a. The base material 1a on which the second step (5) is thus performed is referred to as a base material 1b. This base material 1b is dried by carrying out the step (6).

  Thus, the second step (5) and (6) for the base material 1 is completed. More CNT adheres to the base material 1b than to the base material 1a.

  Then, for the implementation of the next third steps (5) and (6), as in the implementation of the second steps (5) and (6), the process once returns to the step (4) to disperse the second CNT. The concentration of CNT in the liquid 9 is prepared. After this concentration adjustment, step (5) is performed on the base material 1b as shown in FIG. 7 (c). The base material 1b on which the third step (5) is thus performed is referred to as a base material 1c. This base material 1c is dried by carrying out the step (6).

  Thus, the third step (5) and (6) for the base material is completed. More CNTs adhere to the base material 1c than the base material 1b.

  As the number of repetitions of the steps (5) and (6) increases, the amount of CNT adhering to the surface of the base material 1 increases, so the number of repetitions of the steps (5) and (6) is controlled. Thus, the amount of CNT attached to the surface of the base material 1 can be controlled.

  8A to 8E are SEM photographs used to explain the change in the CNT adhesion state on the surface of the base material by the implementation of the above steps (5) and (6).

  FIG. 8A shows carbon fiber 14 that has not been treated.

  FIG. 8B is an SEM photograph of the base material 16 manufactured in the step (3). The base material 16 has the CNTs 15 attached to the surface of the carbon fibers 14.

  FIG. 8C is an SEM photograph of the base material 16a manufactured in the first implementation of the steps (5) and (6). The base material 16 a has CNTs 15 and 15 a attached to the surface of the carbon fiber 14. The CNT 15 a is CNT in the second CNT dispersion 9.

  FIG. 8D is an SEM photograph of base material 16b manufactured in the second implementation of steps (5) and (6). In the base material 16b, CNTs 15, 15a, and 15b are attached to the surface of the carbon fiber 14. The CNT 15 b is CNT in the second CNT dispersion liquid 9.

  FIG. 8E is an SEM photograph of the base material 16c manufactured in the third execution of the steps (5) and (6). In the base material 16 c, CNTs 15, 15 a, 15 b, and 15 c are attached to the surface of the carbon fiber 14. The CNT 15 c is CNT in the second CNT dispersion liquid 9.

  As shown in these SEM photographs, it can be seen that as the number of executions of steps (5) and (6) increases, CNT adheres substantially uniformly on the surface of the base material, and the amount of adhesion increases.

  Thus, a composite material in which CNTs are attached in a predetermined state can be manufactured.

  As described above, according to the present embodiment, the steps (5) and (6) are repeated until the CNT adheres to the surface of the base material in a predetermined state. A composite material adhered in an attached state can be produced. In the base material itself, a plurality of CNTs are directly contacted or directly connected to each other without inclusions and entangled in a network form, and directly contacted or directly connected to the base material surface without inclusions. And immersion and drying are repeated with respect to this preform | base_material until the CNT adheres to the preform | base_material surface by the said process (5) and process (6) to the 2nd CNT dispersion liquid which does not contain an inclusion. Thus, in the present embodiment, a plurality of CNTs are directly contacted or directly connected to each other without inclusions, and are entangled in a network shape and are directly contacted or directly connected to the base material surface without inclusions. Therefore, it is possible to obtain a composite material that can exhibit CNT-derived electrical conductivity and thermal conductivity more than the composite material proposed by the applicant of the present invention, and that has improved mechanical strength. Can do.

  It should be noted that the present invention can be implemented in various other forms without departing from the spirit or main features thereof. Therefore, the above-described embodiment is merely an example in all respects, and the scope of the present invention is shown in the claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the scope of the claims are within the scope of the present invention.

1, 1a to 1c Base material 9 Second CNT dispersion 11, 13 CNT

Claims (10)

A plurality of carbon nanotubes (hereinafter referred to as CNT) are directly contacted or directly connected without inclusions such as a dispersant to form a network, and the plurality of CNTs are directly attached to the surface without the inclusions. A first step of preparing a composite material as a base material;
Preparation of the second CNT dispersion liquid containing no inclusions and in which the CNTs are easily aggregated, and the second and subsequent steps of the third and fourth steps described later, the CNT concentration in the second CNT dispersion liquid A second step of preparation;
A third step of immersing the base material in the second CNT dispersion;
A fourth step of lifting the base material from the second CNT dispersion and drying;
Having at least
The third and fourth steps are performed at least once according to the adhesion state of the CNT to the surface of the base material, and the second and subsequent steps of the third and fourth steps are performed in the second step. Returning to, after the CNT concentration in the second CNT dispersion liquid is prepared, the second and subsequent implementations are performed.
A method for producing a composite material characterized by the above.   The manufacturing method according to claim 1, wherein the composite material has CNT attached to a carbon fiber surface. The first step includes
A first sub-process for dispersing the plurality of CNTs in a CNT solution not containing inclusions such as a dispersant;
By applying predetermined energy to the CNT solution, a first CNT dispersion is produced in which a reversible reaction state in which a state in which the plurality of CNTs are dispersed and a state in which the plurality of CNTs are aggregated in the CNT solution is generated is created. A second sub-step,
When the base material is immersed in the first CNT dispersion liquid and the plurality of CNTs transition from a dispersed state to an aggregated state, the plurality of CNTs are entangled with each other in a network form on the surface of the base material. A third sub-step of directly contacting or directly connecting without inclusions and directly attaching to the surface of the base material without inclusions;
Including
Performing the first sub-step to the third sub-step, and preparing a composite material in which the plurality of CNTs are directly attached to the surface without the inclusions as the base material;
The manufacturing method of Claim 1 or 2. The second step includes
A fourth sub-step of charging the plurality of CNTs into a solution containing no inclusions such as a dispersant;
A fifth sub-process in which a predetermined energy is applied to the solution so that a reversible reaction state in which the state in which the plurality of CNTs are dispersed and the state in which the plurality of CNTs are aggregated is reversibly created in the solution is created. When,
A sixth sub-step of stopping the application of the energy to the solution to obtain the second CNT dispersion;
The manufacturing method as described in any one of Claims 1-3 containing these.   When the second step is the second and subsequent steps of the third and fourth steps, the second step includes a seventh sub-step of adjusting the CNT concentration of the second CNT dispersion, and in the third and fourth steps 5. The manufacturing method according to claim 4, wherein when the second and subsequent operations are performed, the second CNT dispersion liquid in which the CNT concentration is prepared in the seventh sub-step is used.   The manufacturing method according to claim 3, wherein the predetermined energy is ultrasonic energy. A method for producing the first CNT dispersion in the production method according to claim 3,
A first sub-process for dispersing the plurality of CNTs in a CNT solution not containing inclusions such as a dispersant;
By applying energy to the CNT solution, a first CNT dispersion liquid is produced in which a reversible reaction state in which a state in which the plurality of CNTs are dispersed and a state in which the plurality of CNTs are aggregated in the CNT solution is generated is created. Two sub-steps;
The manufacturing method of the 1st CNT dispersion liquid which has this. A method for producing a second CNT dispersion in the production method according to claim 4,
A fourth sub-process of dispersing the plurality of CNTs in a solution not containing inclusions such as a dispersant;
A fifth sub-step of applying a predetermined energy to the solution to create a reversible reaction state in which a state in which the plurality of CNTs are dispersed and agglomerated in the solution are reversibly generated;
A sixth sub-step of stopping the application of the energy to the solution to obtain the second CNT dispersion;
The manufacturing method of the 2nd CNT dispersion liquid which has this.   9. The method for producing a second CNT dispersion liquid according to claim 8, further comprising a seventh sub-process for adjusting a CNT concentration of the second CNT dispersion liquid when the third and fourth processes are performed after the second time.   A composite material having a plurality of CNTs attached to the surface, the composite material manufactured by the manufacturing method according to claim 1.