JP2024056269A - Electrode manufacturing method - Google Patents

Abstract

[Problem] To provide a manufacturing method for an electrode that exhibits conductivity while properly adhering to a stretchable object. [Solution] The manufacturing method for an electrode of the present invention comprises the steps of producing a paint containing conductive particles derived from carbon nanotubes, adhering the paint to a stretchable object, and forming an electrode supported by the object by altering the paint, and in the step of adhering the paint, a screen and a squeegee are used, and the paint is continuously supplied to the screen that is fitted over the object while the squeegee is moved over the screen. [Selected Figure] Figure 2

Description

The present invention relates to a method for manufacturing an electrode.

Metals are the most common and widely used conductors that make up the electrodes. In addition to metals, carbon and other materials are also used as conductor materials. Patent Document 1 discloses a thin-film heater having a thin film made of carbon nanotubes or graphene as a conductor. This thin-film heater is used as a heat source for thermally fixing toner images in electrophotographic image forming devices.

JP 2020-101700 A

The thin-film heaters described above are used with their shape and size remaining almost unchanged. For this reason, they cannot be applied when changes in shape or size are required.

The present invention was conceived in light of the above circumstances, and its objective is to provide a method for manufacturing an electrode that exhibits electrical conductivity while properly adhering to a stretchable object.

The method for manufacturing an electrode provided by the present invention comprises the steps of producing a paint containing conductive particles derived from carbon nanotubes, applying the paint to an elastic object, and forming an electrode supported by the object by altering the paint. In the step of applying the paint, a screen and a squeegee are used, and the paint is continuously supplied to the screen that is fitted to the object while the squeegee is moved over the screen.

In a preferred embodiment of the present invention, the step of producing the paint includes a first dispersion process in which the conductive particles are dispersed in a solvent, and the step of applying the paint includes a second dispersion process in which the conductive particles are dispersed in the paint.

In a preferred embodiment of the present invention, in the second dispersion process, the paint is sprayed by applying pressure.

In a preferred embodiment of the present invention, no dispersant or surfactant is used in the first dispersion process.

The present invention provides a method for manufacturing an electrode that exhibits electrical conductivity while properly adhering to a stretchable object.

Other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

3 is a flowchart showing a method for manufacturing an electrode according to the first embodiment of the present invention. 3A to 3C are schematic cross-sectional views showing a deposition step in the manufacturing method of the electrode according to the first embodiment of the present invention. 3A to 3C are schematic cross-sectional views showing a deposition step in the manufacturing method of the electrode according to the first embodiment of the present invention. 1 is a schematic cross-sectional view showing an electrode manufactured by a method for manufacturing an electrode according to a first embodiment of the present invention. 6 is a flowchart showing a method for manufacturing an electrode according to a second embodiment of the present invention. 11 is a schematic cross-sectional view showing a deposition step in a manufacturing method for an electrode according to a third embodiment of the present invention. FIG.

The preferred embodiment of the present invention will be described in detail below with reference to the drawings.

First Embodiment
1 is a flow chart showing a method for manufacturing an electrode according to a first embodiment of the present invention. The method for manufacturing an electrode according to the present embodiment includes a paint producing step, a paint attaching step, and a paint modifying step.

The paint production process is a process for producing paint that is the raw material for the electrodes produced by this manufacturing method. In this embodiment, the paint production process includes a conductive particle solution production process, a binder solution production process, and a mixing process.

The conductive particle solution generation process is a process for generating a conductive particle solution from conductive particles and a solvent. Carbon nanotubes (single-wall nanotubes, double-wall nanotubes, multi-wall nanotubes, etc.) are selected as the conductive particles. There are no limitations on the size of the carbon nanotubes, and they may be of any size that allows the attachment process, etc., described below, to be realized. As the solvent, for example, cyclohexane, toluene, ethyl acetate, water, etc. are selected. The concentration of the conductive particles in the conductive particle solution is, for example, 10 wt% or less, and preferably 1.0 wt% or less.

The conductive particle solution generating process of this embodiment also serves as the first dispersion process. The first dispersion process is a process for dispersing conductive particles made of carbon nanotubes in a solvent in the conductive particle solution described above. Examples of this dispersion process include a method using ultrasonic waves such as a high-pressure homogenizer, an ultrasonic homogenizer, or an ultrasonic bath, or a method using a stirrer. In addition, in the conductive particle solution generating process, a binder used in the binder solution generating process described below may be added in a diluted form to a low concentration. Furthermore, in the first dispersion process, it is preferable not to use a dispersant or surfactant other than the binder. Through the inventor's testing and research, it has been found that if a dispersant or surfactant other than the binder is used in the first dispersion process, the conductivity of the electrode obtained through the subsequent process decreases and the resistance value increases. By not using a dispersant or surfactant other than the binder in the first dispersion process, the conductivity of the electrode can be improved and the resistance value can be reduced.

The binder liquid generation process is a process for generating a binder liquid that contains a binder. Examples of binders that can be used include silicone, acrylic, and flexible conductive polymers. A solvent may also be added to the binder liquid. Examples of solvents that can be used include cyclohexane, toluene, ethyl acetate, and water.

The mixing process is a process for mixing the conductive particle solution and the binder solution described above. After this mixing process, a dispersion process similar to the first dispersion process described above may be performed.

By going through the above process, the paint is produced.

The paint application process is a process of applying paint to an object. Figures 2 and 3 show the paint application process of this embodiment. In this embodiment, the paint 80 generated in the paint generation process described above is used, and this paint 80 is applied to the object 91. In this embodiment, the paint application process includes a second dispersion process and an application process.

The object 91 is an object on which an electrode is formed by applying the paint 81. The object 91 has elasticity. In this embodiment, the object 91 is, for example, a dielectric elastomer layer. The material of the dielectric elastomer layer is not limited in any way, and preferred examples include silicone elastomer, acrylic elastomer, urethane, HNBR (hydrogenated nitrile rubber), fluorine-based rubber, fluorosilicone, etc.

In this embodiment, the adhesion process is performed by a screen printing method. For example, a screen 171 is placed on the target object 91. The screen 171 is made of cloth or mesh, etc., and has many fine pores. The paint 80 is supplied onto this screen 171.

The paint 80 is supplied by, for example, a paint supplying machine 3. The paint supplying machine 3 has a paint tank 31, a nozzle 32, and a pressure source 33. The paint tank 31 stores the paint 80. The paint tank 31 has a sufficient amount of paint stored therein to supply an appropriate amount of paint 80 to the attachment tank 2. The pressure source 33 pressurizes the paint tank 31 to send the paint 80 to the nozzle 32. The sent-out paint 80 is supplied from the nozzle 32 onto the screen 171. The nozzle 32 preferably functions as a spray. When the paint 80 sent through the nozzle 32 is sprayed by pressure, a sudden pressure change and a strong shear force are applied to the paint 80, and the conductive particles in the paint 80 are locally dispersed. This is the second dispersion process in this embodiment. The nozzle 32 preferably functions as a spray, but is not limited thereto.

As shown in FIG. 2, paint 80 is supplied onto the screen 171, and the squeegee 172 is moved to the right in the figure while being pressed against the screen 171. At this time, paint 80 required for the adhesion process is supplied sequentially in accordance with the movement of the squeegee 172. While moving the squeegee 172 from the state shown in FIG. 2, paint 80 is continuously supplied as shown in FIG. 3. That is, instead of supplying the entire amount of paint 80 to be attached to the object 91 in FIG. 2, the amount of paint 80 required to start the adhesion process is supplied. As the squeegee 172 is moved, the paint 80 on the screen 171 is consumed. By supplying paint 80 sequentially from the nozzle 32, the amount of paint 80 on the screen 171 is maintained so that it does not fall below a predetermined amount.

By moving the squeegee 172 over the entire predetermined range, the paint 80 on the screen 171 is applied to the target object 91 through the screen 171 as a predetermined thickness of paint 81.

Next, a paint alteration process is performed. The paint alteration process is a process for forming the electrode 82 shown in FIG. 4 by altering the paint 81 attached to the target object 91. The specific configuration of the process for altering the paint 81 is not limited in any way, and various conventionally known methods such as drying, heating, and irradiation with light of a specific wavelength can be used. In this embodiment, for example, the paint 81 is altered by natural drying to form the electrode 82.

Next, we will explain the operation of the electrode manufacturing method of this embodiment.

According to this embodiment, as shown in FIG. 4, it is possible to form an electrode 82 on an object 91 having elasticity. The electrode 82 is formed through the paint production process, paint adhesion process, and paint deterioration process described with reference to FIG. 1. By going through these processes, the electrode 82 is able to expand and contract in accordance with the object 91, and exhibits clear electrical conductivity.

In the paint production process, the conductive particle solution production process also serves as the first dispersion process, so that the conductive particles made of carbon nanotubes are appropriately dispersed in the paint 80. In the paint 80, the conductive particles 821 aggregate over time. If the clusters 822 of the conductive particles 821 grow too large due to this aggregation, the flexibility and conductivity of the electrode 82 may be impaired. However, in the paint attachment process, a paint supplying machine 3 having a nozzle 32 that functions as a spray, as shown in Figures 2 and 3, is used. Therefore, the paint 80 is subjected to the second dispersion process by passing through the nozzle 32. When the second dispersion process is performed, even if the conductive particles 821 aggregate in the paint 80, the conductive particles 821 can be dispersed again. Then, immediately after the second dispersion process, the paint 80 is quickly attached to the object 91. As a result, as shown in Figure 4, the electrode 82 has a structure in which the conductive particles 821 are appropriately distributed and each cluster 822 is composed of a plurality of conductive particles 821. The multiple conductive particles 821 that make up the clusters 822 tend to remain bonded together even when the object 91 expands or contracts. This is favorable for maintaining conductivity. Meanwhile, in this structure, gaps that allow air or other atmosphere to enter between the clusters 822 are provided in various places. Due to the presence of these gaps, the electrode 82 has a more flexible nature, with the multiple clusters 822 being in contact with each other and the relative positions and postures of the clusters easily changing. Therefore, the electrode 82 can expand and contract more faithfully following the object 91, which has elasticity.

2 and 3, paint 80 is continuously supplied from nozzle 32 while moving squeegee 172. This makes it possible to prevent an excessive amount of paint 80 from remaining on screen 171. If too much paint 80 remains, there is a concern that the degree of dispersion of conductive particles 821 in paint 80 may decrease. In this embodiment, by limiting the amount of paint 80 on screen 171 to an extent that the adhesion process of the screen printing method can be performed continuously, the conductive particles 821 can be more appropriately maintained in a good dispersion state.

Furthermore, in this embodiment, the paint 80 is sprayed from the nozzle 32 by applying pressure. When the paint 80 is sprayed from the small holes of the nozzle 32 under pressure, a strong shear force acts on the paint 80. This can further promote the redispersion of the conductive particles 821 in the paint 80.

In the paint production process, the resistance value of the electrode 82 can be adjusted in various ways by appropriately setting the concentration of the conductive particles 821 in the paint 80 and the composition of the binder. For example, by setting the resistance value of the electrode 82 to a value close to the resistance value of a common resistor material such as an Fe/Cr/Al alloy (Kanthal: registered trademark) or a Ni/Cr alloy (Nichrome), the electrode 82 can be used as an electric heater. The electrode 82 follows the expansion and contraction of the object 91, so that a flexible and highly elastic electric heater can be formed. On the other hand, by setting the resistance value of the electrode 82 to a value close to the resistance value of a common good conductor, the electrode 82 can be used as a flexible and highly elastic wiring material, etc.

Figures 5 and 6 show another embodiment of the present invention. In these figures, elements that are the same as or similar to those in the above embodiment are given the same reference numerals as those in the above embodiment.

Second Embodiment
5 shows a method for manufacturing an electrode according to a second embodiment of the present invention. In this embodiment, the paint production step does not include the binder production process and the mixing process in the above-mentioned embodiment. That is, the paint 80 in this embodiment does not include the above-mentioned binder. Even in this embodiment, the electrode 82 can be formed by modifying the paint 80. Furthermore, after the electrode 82 is formed, an additional layer may be formed by spraying the binder. Alternatively, the binder may be allowed to permeate the electrode 82. The binder liquid may be either conductive or insulating, and is preferably one having a suitable degree of elasticity.

Third Embodiment
6 shows a coating step in a method for producing an electrode according to a third embodiment of the present invention. In this embodiment, the coating material feeder 3 has a re-dispersion device 34, which is used to perform the second dispersion process and to feed the coating material 80 onto the screen 171.

For example, paint 80 is supplied from paint tank 31 to redispersion device 34 by pressure from pressure source 33. Redispersion device 34 performs a second dispersion process to disperse conductive particles 821 in the supplied paint 80. Examples of redispersion device 34 include dispersion devices that use ultrasonic waves, such as a high-pressure homogenizer, an ultrasonic homogenizer, and an ultrasonic bath. The paint 80 that has been subjected to the second dispersion process in redispersion device 34 is sequentially supplied from redispersion device 34 onto screen 171.

This embodiment also makes it possible to form an electrode 82 on an elastic object 91. As can be understood from this embodiment, the means for performing the second dispersion process of the present invention is not limited to a configuration in which paint 80 is sprayed from a nozzle 32 by applying pressure, but can be set in various ways, such as a configuration in which a redispersion device 34 is used.

The electrode manufacturing method according to the present invention is not limited to the above-mentioned embodiment. The specific configuration of the electrode manufacturing method according to the present invention can be freely designed in various ways.

2: Adhesion tank 3: Paint supply machine 31: Paint tank 32: Nozzle 33: Pressure source 34: Redispersion device 80: Paint 81: Paint 82: Electrode 91: Object 171: Screen 172: Squeegee 821: Conductive particles 822: Cluster

Claims (4)

forming a coating material comprising conductive particles derived from carbon nanotubes;
Applying the paint to an object having elasticity;
and forming an electrode supported on the object by modifying the paint,
In the step of applying the paint, a screen and a squeegee are used, and the paint is continuously supplied to the screen that is fitted over the object while the squeegee is moved over the screen. The step of producing the paint includes a first dispersion process of dispersing the conductive particles in a solvent;
The method for manufacturing an electrode according to claim 1 , wherein the step of applying the paint includes a second dispersion process of dispersing the conductive particles in the paint. The method for manufacturing an electrode according to claim 2, wherein in the second dispersion process, the paint is sprayed by applying pressure. The method for manufacturing an electrode according to claim 2 or 3, wherein no dispersant or surfactant is used in the first dispersion treatment.

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