JP2018172250A - Method for making carbon nanotube web and method for producing carbon nanotube yarn - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for making carbon nanotube web in which a carbon nanotube in carbon nanotube array is reliably drawn out.SOLUTION: The method for making carbon nanotube array web includes: an array making step of making a carbon nanotube array (1) on a substrate (3); a first applying step of applying a metal thin film (M) to the non-contact surface (1b) of the carbon nanotube array (1); a peeling step of peeling the carbon nanotube array (1) from the substrate (3); and a drawing out step of drawing out a carbon nanotube web from the carbon nanotube array (1).SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method of making a carbon nanotube web by extracting the carbon nanotube web from an array of carbon nanotubes.

  Carbon nanotubes are attracting attention as materials having excellent electrical conductivity, thermal conductivity, and mechanical strength, and have been used in various fields. When carbon nanotubes are used, the carbon nanotubes may be formed into a film shape (also called a web) or a thread shape depending on the usage.

  A film-like carbon nanotube (hereinafter referred to as a carbon nanotube web) can be produced, for example, as follows. That is, first, a carbon nanotube array including a plurality of carbon nanotubes arranged in a certain direction on a substrate is produced. Next, a predetermined amount of carbon nanotubes are drawn out from the produced carbon nanotube array in a direction perpendicular to the alignment direction (also called drawing). As a result, the van der Waals force acting between the carbon nanotubes allows the carbon nanotube web to be drawn from the carbon nanotube array one after another from the carbon nanotube array.

  By the way, it is desired to improve the physical properties (for example, conductivity, tensile strength, etc.) of the carbon nanotube web produced by twisting the carbon nanotube web or the carbon nanotube web. For example, Patent Document 1 discloses a technique for producing carbon nanotube fibers having high tensile strength by supporting fine particles on a carbon nanotube web.

  The technique disclosed in Patent Document 1 includes a step of supporting fine particles on the surface of a plurality of carbon nanotubes produced on a substrate, and a step of extracting a part of the carbon nanotubes supporting the fine particles.

JP 2011-136874 A (published July 14, 2011)

  However, the technique disclosed in Patent Document 1 has the following problems. That is, some of the carbon nanotubes produced on the substrate may be strongly caught (bonded) with the substrate. In such a case, when pulling out the carbon nanotubes produced on the substrate, there is a problem that the carbon nanotubes that are strongly caught with the substrate cannot be pulled out, and the carbon nanotubes remain on the substrate.

  An object of one embodiment of the present invention is to realize a carbon nanotube web manufacturing method that can reliably pull out carbon nanotubes in a carbon nanotube array.

  In order to solve the above problems, a method of manufacturing a carbon nanotube web according to one embodiment of the present invention includes an array manufacturing step of manufacturing an array of carbon nanotubes on a substrate, which includes a plurality of carbon nanotubes oriented in a certain direction. And after the array fabrication step, a first imparting step of imparting a substance to the carbon nanotubes on the surface of the array opposite to the surface in contact with the substrate, and after the first imparting step, A peeling step of peeling the array from the substrate, and a drawing step of drawing a web of carbon nanotubes from the array peeled by the peeling step.

  According to one aspect of the present invention, there is an effect that the carbon nanotubes in the carbon nanotube array can be reliably pulled out.

It is sectional drawing which shows the carbon nanotube array used in manufacture of the carbon nanotube web which concerns on Embodiment 1 of this invention. BRIEF DESCRIPTION OF THE DRAWINGS The 1st provision process which concerns on Embodiment 1 of this invention is demonstrated, (a) is sectional drawing of a carbon nanotube array which shows a mode that the metal is sputtered to the non-contact surface of a carbon nanotube array, ( b) is a cross-sectional view of the carbon nanotube array after sputtering the metal to the carbon nanotube array. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a peeling process according to Embodiment 1 of the present invention, in which (a) is a cross-sectional view of a carbon nanotube array after a metal is sputtered onto the carbon nanotube array, and (b) is a cross-sectional view of the carbon nanotube array from a substrate. It is sectional drawing of the carbon nanotube array after peeling. BRIEF DESCRIPTION OF THE DRAWINGS It is for demonstrating the extraction process which concerns on Embodiment 1 of this invention, (a) is a figure which shows the carbon nanotube array before pulling out a carbon nanotube web from a carbon nanotube array, (b) is a carbon nanotube array It is a figure which shows a mode that the carbon nanotube web is pulled out from. FIG. 6 illustrates a second application step according to Embodiment 2 of the present invention, and FIG. 6A is a cross-sectional view of a carbon nanotube array showing a state in which a metal is sputtered on a contact surface of the carbon nanotube array; ) Is a cross-sectional view of the carbon nanotube array after sputtering the metal to the carbon nanotube array. It is for demonstrating the extraction | drawer process which concerns on Embodiment 2 of this invention, (a) is a figure which shows the carbon nanotube array before pulling out a carbon nanotube web from a carbon nanotube array, (b) is a carbon nanotube array It is a figure which shows a mode that a carbon nanotube web is pulled out from.

Embodiment 1
Hereinafter, a method for producing a carbon nanotube web in Embodiment 1 of the present invention will be described in detail with reference to the drawings. In the present specification, “A to B” means “A or more and B or less”.

  The method for producing a carbon nanotube web in the present embodiment includes an array production process, a first application process, a peeling process, and a drawing process. Details of each step will be described below.

  Hereinafter, carbon nanotubes are abbreviated as “CNT”, carbon nanotube arrays (carbon nanotube arrays) as “CNT arrays”, and carbon nanotube webs (carbon nanotube webs) as “CNT webs”.

(Array manufacturing process)
The array fabrication process will be described with reference to FIG. FIG. 1 is a cross-sectional view showing a CNT array 1 used in the present embodiment.

  The array manufacturing process is a process of manufacturing a CNT array 1 including a plurality of CNTs 2 oriented in a certain direction on a substrate.

  As shown in FIG. 1, the CNT array 1 in the present embodiment is configured by forming a plurality of CNTs 2 whose major axis direction is oriented substantially perpendicular to the substrate 3. The CNT array 1 is manufactured by a chemical vapor deposition method (CVD: Chemical Vapor Deposition). Below, the manufacturing method of the CNT array 1 is demonstrated.

  The CNT array 1 is formed by placing a substrate 3 having a catalyst layer formed on the surface thereof in a thermal CVD chamber preheated to a predetermined temperature (600 to 1000 ° C.) and flowing gas into the thermal CVD chamber for a predetermined time. It is formed.

  More specifically, in this embodiment, a stainless steel substrate is used as the substrate 3. However, the substrate 3 is not limited to a stainless steel substrate, and for example, a silicon substrate, a quartz substrate, or the like may be used. When a stainless steel substrate is used as the substrate 3, it is preferable to form a buffer layer between the substrate 3 and the catalyst layer. Thereby, the influence of chromium, which is a constituent element of stainless steel, on the catalyst layer can be prevented. The buffer layer is made of, for example, silica or alumina. In addition, the board | substrate 3 in this embodiment should just be a board | substrate which has the surface for forming the CNT array 1, and is not restricted to a plate-shaped member.

  In the present embodiment, the catalyst layer is made of iron (Fe), and is formed by an EB (Electron Beam) method. However, the catalyst layer in the present invention is not limited to Fe, and may be composed of, for example, cobalt (Co) or nickel (Ni). Further, the catalyst layer in the present invention may be formed by a sputtering method, a vacuum deposition method, or the like.

  In the present embodiment, acetylene is used as the gas. However, the gas in the present invention may be an alkane such as methane, ethane, propane or hexane, an unsaturated organic compound such as ethylene or propylene, or an aromatic compound such as benzene or toluene.

By being manufactured as described above, the CNTs 2 constituting the CNT array 1 in the present embodiment are multilayer CNTs having an outer diameter of 10 to 30 nm, a length of 50 to 1000 μm, and 5 to 10 layers. The CNT array 1 is preferably one in which 10 ⁹ to 10 ¹¹ CNTs ² are formed per 1 cm ² .

  Note that the CNT array used in the present invention is not limited to the above. That is, the CNT array used in the present invention may be an aggregate of CNTs grown on a substrate so that at least a part of the major axis direction is oriented in a certain direction as described above. Alternatively, the CNT2 may be, for example, a single-walled CNT or a multilayered CNT having two or more layers.

(First application process)
Next, the 1st provision process in this embodiment is demonstrated, referring FIG. FIG. 2 is a cross-sectional view of the CNT array 1 illustrating a first application process in the present embodiment, wherein (a) is a cross-sectional view of the CNT array 1 showing a state in which a metal is sputtered onto the non-contact surface 1b of the CNT array 1. FIG. 4B is a cross-sectional view of the CNT array 1 after sputtering the metal on the CNT array 1.

  The first application step is a step of applying a substance that prevents dissociation of the CNTs 2 to the surface of the CNT array 1 opposite to the surface in contact with the substrate 3 after the array manufacturing step. Hereinafter, the surface of the CNT array 1 that contacts the substrate 3 will be described as a contact surface 1a, and the surface opposite to the contact surface 1a will be described as a non-contact surface 1b.

  In the first application step in the present embodiment, as shown in FIG. 2A, a metal is supported on the non-contact surface 1 b of the CNT array 1 by sputtering using a sputtering apparatus S. Thereby, as shown in FIG. 2B, the metal thin film M is supported on the non-contact surface 1 b of the CNT array 1.

  The metal supported on the non-contact surface 1b is not particularly limited as long as it can prevent dissociation between the CNTs 2. However, in order to further improve the conductivity in the carbon nanotube yarn (CNT yarn) produced by twisting the CNT web 10 drawn in the drawing step described later or the CNT web 10, the metal to be supported is gold (Au), silver (Ag), and copper (Cu) are preferable, and gold (Au) is most preferable.

  The amount of metal supported on the non-contact surface 1b is preferably such that the supported thickness of the thin film M is 1 nm to 10 μm, and more preferably 10 nm to 500 nm.

  When the carrying thickness of the thin film M is smaller than 1 nm, it is not preferable for the following reason. That is, when the carrying thickness of the thin film M is smaller than 1 nm, the effect of suppressing dissociation between the CNTs 2 becomes small, which will be described later. In the peeling process, the alignment state of the CNTs 2 in the CNT array 1 is disturbed. As a result, there is a high possibility that the CNT web 10 cannot be pulled out from the CNT array 1 in a drawing step described later.

  Moreover, when the carrying | support thickness of the thin film M is larger than 10 micrometers, it is unpreferable for the following reasons. That is, when the carrying thickness of the thin film M is larger than 10 μm, the strength of the bond between the carried metal and the CNT 2 becomes high. As a result, it becomes difficult to pull out the CNTs 2 from the CNT array 1 in the drawing step described later.

  In the first application step in this embodiment, the metal thin film M is supported on the non-contact surface 1b of the CNT array 1 by sputtering the metal. However, the method for producing the CNT web of the present invention is not limited to this. Absent. In the first application step of one embodiment of the present invention, the metal thin film M may be supported on the non-contact surface 1b of the CNT array 1 by vapor deposition.

(Peeling process)
Next, the peeling process in this embodiment is demonstrated, referring FIG. FIGS. 3A and 3B illustrate a peeling process in the present embodiment. FIG. 3A is a cross-sectional view of the CNT array 1 after a metal is sputtered onto the CNT array 1, and FIG. It is sectional drawing of the CNT array 1 after peeling from. FIG. 3B shows the CNT array 1 in a state where the CNT array 1 is peeled from the substrate 3 and the CNT array 1 is turned upside down.

  In the peeling step in the present embodiment, the CNT array 1 (more specifically, the contact surface 1a of the CNT array 1) is peeled from the substrate 3 as shown in FIGS. The CNT array 1 can be peeled off by inserting a thin blade such as a cutter between the substrate 3 and the contact surface 1a of the CNT array 1, for example.

  Here, as in the prior art, when no substance is applied to the non-contact surface 1b of the CNT array 1, the alignment state of the CNT 2 in the CNT array 1 is very delicate, and therefore the CNT array 1 is peeled from the substrate 3. At this time, the alignment state of the CNTs 2 in the CNT array 1 is broken. As a result, there is a possibility that the CNT 2 cannot be pulled out from the CNT array 1.

  In contrast, in this embodiment, as described above, the metal thin film M is supported on the non-contact surface 1b of the CNT array 1 in the first application step. Thereby, when the CNT array 1 is peeled from the substrate 3, it is possible to suppress the collapse of the orientation state of the CNTs 2 in the CNT array 1.

(Drawing process)
Next, the drawing process in this embodiment will be described with reference to FIG. 4A and 4B are diagrams for explaining a drawing process in the present embodiment. FIG. 4A is a diagram showing the CNT array 1 before the CNT web 10 is pulled out from the CNT array 1, and FIG. 4B is a diagram showing the CNT array 1. It is a figure which shows a mode that the CNT web 10 is pulled out from.

  The drawing step is a step of pulling out the CNT web 10 from the CNT array 1 peeled by the peeling step. Here, the CNT web is formed by drawing a part of CNTs from the CNT array in a predetermined direction (typically, a direction along the surface of the base material) and pulling out other CNTs continuously. It means an aggregate of mesh-like CNTs. This phenomenon occurs because each CNT constituting the CNT array is bundled with neighboring CNTs by van der Waals force. In addition, the technique of pulling out the CNT web from the CNT array is generally sometimes referred to as “CNT spinning”.

  In the drawing process in the present embodiment, as shown in FIG. 4A, a bundle of a predetermined amount of CNTs 2 existing at the drawing direction end of the CNT array 1 is attached to a pulling member (not shown) of the pulling device. Next, the tension member is moved in the pull-out direction and in the direction away from the substrate 3 (the arrow direction shown in FIG. 4A). Thereby, the bundle of CNTs 2 attached to the tension member is detached from the substrate 3 and pulled out from the CNT array 1.

  Further, as shown in FIG. 4B, when the tensile member is moved in a direction away from the substrate 3 (in the direction of the arrow shown in FIG. 4B), the drawn CNT 2 and the CNT array 1 exist. Due to the van der Waals force acting between the CNT 2 and the CNT 2, the CNT 2 is pulled out one after another from the CNT array 1 to form the CNT web 10, and the CNT web 10 is pulled out.

  In this embodiment, since the CNT array 1 is peeled from the substrate 3 in the peeling step, almost all CNTs 2 existing in the CNT array 1 can be drawn out as the CNT web 10. That is, unlike the prior art, the CNT 2 does not remain on the substrate 3 due to the catch between the CNT 2 of the CNT array 1 and the substrate. That is, the method for producing the CNT web 10 in the present embodiment can reliably pull out the CNTs in the CNT array 1.

  In the present embodiment, the metal thin film M is supported on the non-contact surface 1b of the CNT array 1 in the first application step. Thereby, the CNT web 10 drawn in the drawing step becomes a CNT web mixed with metal. As a result, the conductivity of the CNT web 10 of this embodiment can be improved compared to the conventional CNT web. Thereby, for example, the CNT web 10 can be applied to a sensor or the like.

  Conventionally, after pulling out a CNT web from a CNT array, a metal is supported on the CNT web by sputtering or the like. However, in this method, the metal can be supported only on the surface of the CNT web, and the conductivity of the CNT web could not be greatly improved.

  On the other hand, in this embodiment, after the metal thin film M is supported on the non-contact surface 1b of the CNT array 1, the CNT web 10 is pulled out. Thereby, a metal can be mixed in the inside of the CNT web 10 drawn by the drawing process. As a result, the strength and conductivity of the CNT web 10 can be remarkably improved, and the mixed metal can be used as a catalyst.

<Carbon nanotube yarn>
Next, the CNT yarn in this embodiment will be described.

  The manufacturing method of the CNT yarn in this embodiment includes a step of twisting the CNT web 10 manufactured by the above-described manufacturing method (twisting yarn step).

  Since the CNT yarn in this embodiment is produced using the CNT web 10 mixed with metal, the CNT yarn is mixed with metal. As a result, the CNT yarn in the present embodiment can be a CNT yarn having improved conductivity as compared with the conventional CNT yarn.

<Modification>
Next, a modification of the method for producing a CNT web in Embodiment 1 will be described. The method for producing the CNT web in this modification is different in the substance carried on the non-contact surface 1b of the CNT array 1 in the first application step.

  In the first application step in this modification, a polymer compound (polymer substance) is supported on the non-contact surface 1b of the CNT array 1 by vapor deposition using a vapor deposition device (not shown). As a result, the thin film of the polymer compound is supported on the non-contact surface 1 b of the CNT array 1. Thereby, when the CNT array 1 is peeled from the substrate 3, it is possible to suppress the collapse of the orientation state of the CNTs 2 in the CNT array 1.

  The amount of the polymer compound supported on the non-contact surface 1b is preferably 1 nm to 10 μm and more preferably 10 nm to 500 nm.

  The polymer compound is preferably a compound having a high binding property with CNT2, and for example, a polyimide compound, a polyamide compound, polyethylene terephthalate, polystyrene, polyethylene, or the like can be used.

  The CNT web 10 in this modification is manufactured by performing the said extraction process with respect to the CNT array 1 by which the high molecular compound was carry | supported by the non-contact surface 1b. As a result, the high molecular compound is mixed in the inside (especially the joint of CNT2) of the CNT web 10 in this modification. Thereby, the strength of the CNT web 10 or the strength of the CNT yarn can be improved by heating the CNT web 10 in the present modification, or the CNT yarn manufactured by twisting the CNT web 10 in the present modification. it can.

  In addition, although the above-mentioned Embodiment 1 and the modification were the aspects which carry | support a metal or a high molecular compound in a 1st provision process, the preparation methods of the CNT web of this invention are not restricted to this. In the CNT web manufacturing method of one embodiment of the present invention, in the first application step, a ceramic or carbon material may be supported on the non-contact surface 1b of the CNT array 1 by vapor deposition or etching. By supporting the ceramic, the functionality of the ceramic can be imparted to the CNT web 10. For example, the heat conductivity of the CNT web 10 can be improved by mixing a heat conductive material such as aluminum nitride into the CNT web 10. For example, the surface area of the CNT web 10 can be increased by supporting activated carbon as a carbon material in the first application step. Further, for example, by supporting carbon black supporting a metal (for example, platinum (Pt)) in the first application step, the CNT web 10 can be used as a catalyst for a fuel cell.

[Embodiment 2]
Another embodiment of the present invention will be described below with reference to the drawings. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

  The method for producing the CNT web 10 in the present embodiment is that the CNT web 10 in the first embodiment further includes a second application step between the peeling step and the drawing step in the method for producing the CNT web 10 in the first embodiment. It is different from the manufacturing method.

(Second granting process)
The 2nd provision process in this embodiment is demonstrated referring FIG. FIG. 5 illustrates a second application step in the present embodiment, and (a) is a cross-sectional view of the CNT array 1 showing a state in which a metal is sputtered onto the contact surface 1a of the CNT array 1, b) is a cross-sectional view of the CNT array 1 after the CNT array 1 is sputtered with metal.

  In the second application step, as shown in FIG. 5A, a metal is supported by the contact surface 1a of the CNT array 1 peeled from the substrate 3 in the peeling step using a sputtering apparatus S. Thereby, as shown in FIG. 5B, the metal thin film M is supported on the contact surface 1 a of the CNT array 1. That is, the metal thin film M is supported on the contact surface 1 a and the non-contact surface 1 b of the CNT array 1.

  6A and 6B are diagrams for explaining a drawing process in the present embodiment. FIG. 6A is a view showing the CNT array 1 before the CNT web 10 is drawn from the CNT array 1, and FIG. It is a figure which shows a mode that the CNT web 10 is pulled out from.

  In the drawing process in the present embodiment, as shown in FIG. 6A, a bundle of a predetermined amount of CNTs 2 existing at the drawing direction end of the CNT array 1 is attached to a pulling member (not shown) of the pulling device. Next, the tension member is moved in the pull-out direction and in the direction away from the substrate 3 (the arrow direction shown in FIG. 6A). Thereby, the bundle of CNTs 2 attached to the tension member is detached from the substrate 3 and pulled out from the CNT array 1.

  Further, as shown in FIG. 6 (b), when the tensile member is moved in a direction away from the substrate 3 (in the direction of the arrow shown in FIG. 6 (b)), the drawn CNT 2 and the CNT array 1 exist. Due to the van der Waals force acting between the CNT 2 and the CNT 2, the CNT 2 is pulled out one after another from the CNT array 1 to form the CNT web 10, and the CNT web 10 is pulled out.

  In this embodiment, the CNT web 10 is formed from the CNT array 1 in which the metal thin film M is supported on the contact surface 1a and the non-contact surface 1b. Thereby, the quantity of the metal mixed in the CNT web 10 can be increased. As a result, it is possible to further improve the conductivity of the CNT yarn produced by twisting the CNT web 10 or the CNT web 10.

  In the present embodiment, the metal is supported on the CNT array 1 in the first application step and the second application step, but the method of manufacturing the CNT web 10 of the present invention is not limited to this. The method for producing the CNT web 10 of one aspect of the present invention may be an aspect in which a metal is supported in the first application step and a polymer compound is supported in the second application step. Thereby, the CNT web 10 or CNT thread | yarn which improved electroconductivity and intensity | strength can be produced.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

1 CNT array (carbon nanotube array, carbon nanotube array)
1a Contact surface 1b Non-contact surface 2 CNT (carbon nanotube)
3 Substrate 10 CNT web (carbon nanotube web, carbon nanotube web)
M thin film

Claims (4)

An array fabrication process for fabricating an array of carbon nanotubes on a substrate, including a plurality of carbon nanotubes oriented in a certain direction;
A first application step of applying a substance to the carbon nanotubes on the surface of the array opposite to the surface in contact with the substrate after the array production step;
A peeling step of peeling the array from the substrate after the first application step;
And a drawing step of pulling out the carbon nanotube web from the array peeled by the peeling step.   2. The carbon nanotube web according to claim 1, wherein in the first application step, a metal or a polymer substance having a high binding property with the carbon nanotube is applied to the opposite surface by sputtering or vapor deposition. Manufacturing method.   3. The method according to claim 1, further comprising a second application step of applying a substance to a surface of the array that has been in contact with the substrate between the peeling step and the drawing step. A method for producing a carbon nanotube web.   The manufacturing method of the carbon nanotube yarn characterized by including the twisting process which twists the web produced by the production method of the carbon nanotube web of any one of Claims 1-3.

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