Manufacturing method of dielectric elastomer device

Abstract

To provide a manufacturing method of a dielectric elastomer device capable of more appropriately manufacturing a dielectric elastomer device.SOLUTION: A manufacturing method of a dielectric elastomer device includes an elastomer expansion step, a carbon-based conductive material generation step, an electrode formation step, a support material mount step, and an unwanted portion removal step. The manufacturing method of the dielectric elastomer device further includes at least any of: a first inspection step of inspecting a film thickness of an elastomer material after the elastomer expansion step and before the electrode formation step; a second inspection step of inspecting a dispersion state of a dispersant in the carbon-based conductive material generation step; a third inspection step of inspecting the coating state of the carbon-based conductive material after coating processing and before drying processing in the electrode formation step; a fourth inspection step of inspecting an electric resistance value of an electrode after the electrode formation step and before the support material mount step; and a fifth inspection step of inspecting the operation of the dielectric elastomer device after the unwanted portion removal step.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for making a dielectric elastomer device. [Background technology]

[0002] Patent Document 1 discloses an example of a dielectric elastomer device. The dielectric elastomer device disclosed in the document includes a dielectric elastomer layer and a pair of electrode layers. The dielectric elastomer device functions as, for example, an actuator, a sensor, a power generation element, etc. When the dielectric elastomer device is in operation, significant expansion and contraction occurs in the dielectric elastomer layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-032586 Summary of the Invention [Problem to be solved by the invention]

[0004] If the dielectric elastomer layer is not manufactured properly, it may be inhibited from stretching or may even be damaged during operation of the dielectric elastomer device.

[0005] The present invention has been devised in light of the above circumstances, and an object of the present invention is to provide a method for manufacturing a dielectric elastomer device that enables a dielectric elastomer device to be manufactured more appropriately. [Means for solving the problem]

[0006] The method for manufacturing a dielectric elastomer device provided by the present invention comprises an elastomer stretching step, a carbon-based conductive material generating step, an electrode forming step, a support material attaching step, and an unnecessary portion removing step, and further comprises at least one of a first inspection step of inspecting the film thickness of the elastomer material after the elastomer stretching step and before the electrode forming step, a second inspection step of inspecting the dispersion state of the dispersion liquid in the carbon-based conductive material generating step, a third inspection step of inspecting the application state of the carbon-based conductive material after the application process and before the drying process in the electrode forming step, a fourth inspection step of inspecting the electrical resistance value of the electrode after the electrode forming step and before the support material attaching step, and a fifth inspection step of inspecting the operation of the dielectric elastomer device after the unnecessary portion removing step. Effect of the Invention

[0007] According to the present invention, dielectric elastomer devices can be manufactured more appropriately.

[0008] Other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0009] [Figure 1] 1A and 1B are an oblique view and a partially enlarged cross-sectional view showing an example of a dielectric elastomer device manufactured by a method for manufacturing a dielectric elastomer device according to the present invention. [Diagram 2] 1 is a flow chart illustrating one embodiment of a method for manufacturing a dielectric elastomer device according to the present invention. [Diagram 3] 1 is a flow chart illustrating one embodiment of a method for manufacturing a dielectric elastomer device according to the present invention. [Figure 4] 1 is a flow chart illustrating one embodiment of a method for manufacturing a dielectric elastomer device according to the present invention. [Diagram 5] 1 is a flow chart illustrating one embodiment of a method for manufacturing a dielectric elastomer device according to the present invention. [Figure 6] 1 is a flow chart illustrating one embodiment of a method for manufacturing a dielectric elastomer device according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0011] Fig. 1 shows an example of a dielectric elastomer device manufactured by the method for manufacturing a dielectric elastomer device according to the present invention. The dielectric elastomer device A1 shown in the figure includes a dielectric elastomer layer 1, a pair of electrode layers 2A and 2B, and a support material 3.

[0012] The dielectric elastomer layer 1 is required to be elastically deformable and to be an insulator. The material of the dielectric elastomer layer 1 is not particularly limited, but preferred examples include silicone elastomer, acrylic elastomer, urethane, HNBR (hydrogenated nitrile rubber), fluorine-based rubber, fluorosilicone, etc. The shape of the dielectric elastomer layer 1 is not limited at all.

[0013] The pair of electrode layers 2A, 2B are disposed on both sides of the dielectric elastomer layer 1 in the thickness direction. The pair of electrode layers 2A, 2B are formed of a material that is conductive and can undergo elastic deformation to follow the elastic deformation of the dielectric elastomer layer 1. The pair of electrode layers 2A, 2B contain, for example, one or more of conductive materials such as carbon materials, conductive polymer compounds, and metal materials. Examples of carbon materials include graphite, fullerene, carbon nanotubes (CNTs), and graphene. The carbon materials may be subjected to, for example, one or more of processes such as metal doping, metal encapsulation, and metal plating. Examples of conductive polymer compounds include polyacetylene, polythiophene, polypyrrole, polyphenylene, polyphenylenevinylene, and polybenzothiazole. Examples of metal materials include silver (Ag), gold (Au), and aluminum (Al), and may be alloys.

[0014] The specific configuration of the dielectric elastomer device manufactured by the manufacturing method of the dielectric elastomer device according to the present invention is not limited in any way. In the example shown in Fig. 1, the device includes a pair of dielectric elastomer layers 1, two pairs of electrode layers 2A, 2B arranged on both sides of each dielectric elastomer layer 1, a central member 31, a pair of peripheral members 32, and a control unit 4. The partially enlarged cross-sectional view in the figure shows one of the pair of dielectric elastomer layers 1, the pair of electrode layers 2A, 2B arranged on both sides of the dielectric elastomer layer 1, and the control unit 4.

[0015] The dielectric elastomer layer 1 in this example has a circular or annular shape. The portions near the center of the pair of dielectric elastomer layers 1 are fixed to a central member 31. The peripheral portions of the pair of dielectric elastomer layers 1 are individually fixed to a pair of peripheral members 32. The pair of peripheral members 32 are spaced apart in the vertical direction, sandwiching the central member 31 therebetween. The pair of peripheral members 32 are fixed apart from each other by a number of rods 33. As a result, tension is generated in each of the pair of dielectric elastomer layers 1 when no voltage is applied to the pair of electrode layers 2A, 2B.

[0016] The control unit 4 is for applying voltage to the two pairs of electrode layers 2A, 2B individually, and includes, for example, a power supply unit. When the control unit applies a voltage to the pair of electrode layers 2A, 2B at the top in the figure, the dielectric elastomer layer 1 at the top in the figure expands, and the dielectric elastomer layer 1 at the bottom in the figure contracts. This causes the central member 31 to move downward in the figure. Conversely, when the control unit applies a voltage to the pair of electrode layers 2A, 2B at the bottom in the figure, the dielectric elastomer layer 1 at the bottom in the figure expands, and the dielectric elastomer layer 1 at the top in the figure contracts. This causes the central member 31 to move upward in the figure. In this way, the voltage application is controlled by the control unit 4, so that the central member 31 can be moved in the vertical direction in the figure, and the dielectric elastomer device A1 functions as an actuator. In this embodiment, the two pairs of electrode layers 2A, 2B and the control unit 4 are connected at two pairs of power supply points 29A, 29B. Each power supply point 29A is a point where each electrode layer 2A is connected to the control unit 4. Each power supply point 29B is a point where each electrode layer 2B is connected to the control unit 4. The power supply points 29A, 29B provided on the pair of electrode layers 2A, 2B are provided so that their positions are shifted from each other, and in the example shown in the figure, they are disposed at positions shifted by approximately 90 degrees.

[0017] 2 to 6 show one embodiment of the method for manufacturing a dielectric elastomer device according to the present invention. The method for manufacturing a dielectric elastomer device of this embodiment includes an elastomer stretching step, a carbon-based conductive material generating step, an electrode forming step, a support material mounting step, and an unnecessary part removing step, and further includes at least one of a first inspection step, a second inspection step, a third inspection step, a fourth inspection step, and a fifth inspection step.

[0018] [Elastomer stretching process] The elastomer stretching process is a process of stretching an elastomer material that becomes the dielectric elastomer layer 1. As shown in Figure 3, in the illustrated example, the elastomer stretching process includes, but is not limited to, an elastomer preparation process, an elastomer longitudinal stretching process, and an elastomer lateral stretching process.

[0019] In the elastomer preparation process, first, an elastomer material is prepared. The elastomer material is prepared in various forms, such as a rolled form or a sheet-like form. Next, the elastomer material is cut to a size suitable for the elastomer longitudinal stretching process and the elastomer lateral stretching process. If the elastomer material is already supplied in an appropriate size, cutting may be omitted. If a protective sheet or the like is attached to protect the elastomer material, this protective sheet or the like is peeled off. Next, the elastomer material is washed as necessary, or a predetermined primer is applied. In addition, the end surface of the elastomer material may be protected by applying an elastic paint or the like to the end surface of the elastomer material or by attaching an adhesive sheet to the end surface.

[0020] In the elastomer longitudinal stretching process, for example, an elastomer material is attached to a predetermined stretching device. Then, the elastomer material is stretched in one direction (longitudinal direction) included in the in-plane direction of the elastomer material by the stretching device. This stretching is, for example, about 150% to 500%, assuming that the longitudinal length of the elastomer material before stretching is 100%.

[0021] In the elastomer lateral stretching process, the elastomer material is stretched by the above-mentioned stretching device in one direction included in the in-plane direction of the elastomer material and perpendicular to the longitudinal direction (lateral direction). For example, this stretching is about 150% to 500% when the lateral length of the elastomer material before stretching is 100%. Note that the elastomer longitudinal stretching process and the elastomer lateral stretching process may be performed after one is completed, or at least a part of each may be performed simultaneously in parallel. Note that the directions in which the elastomer material is stretched are not limited to two directions perpendicular to each other. The number of directions may be three or more as long as they are two or more directions included in the in-plane direction of the elastomer material, and the angles between the directions are not limited and can be set appropriately to various angles.

[0022] [First inspection process] After the elastomer stretching step, but before the electrode forming step, a first inspection step may be performed to check whether the elastomer material is in a proper condition after stretching.

[0023] As an example of the first inspection process, after the elastomer longitudinal stretching process and the elastomer lateral stretching process are completed, the elastomer material is left for a certain period of time. Next, the film thickness of the elastomer material is measured. For the film thickness measurement, it is preferable to measure four locations around the periphery of one sheet of elastomer material, and more preferably to measure eight or more locations. The desirable range of film thickness is preferably within ±10% when the specified film thickness is taken as 100%.

[0024] [Carbon-based conductive material production process] In the carbon-based conductive material producing step, a carbon-based conductive material used to form a pair of electrode layers 2A, 2B is produced. In the following description, the "carbon-based conductive material" may be referred to as an "electrode material." As shown in FIG. 4, in the illustrated example, the carbon-based conductive material producing step includes, but is not limited to, a carbon-based conductive filler dispersion process, a supernatant extraction process, and a binder mixing process.

[0025] In the carbon-based conductive filler dispersion process, a carbon-based conductive filler is prepared and dispersed in a predetermined liquid. Examples of the carbon-based conductive filler include graphite, fullerene, carbon nanotubes (CNTs), and graphene. Examples of the liquid include water, alcohol, and hexane. This results in a dispersion liquid containing the carbon-based conductive filler.

[0026] In the supernatant extraction process, the supernatant of the dispersion liquid that has been left to stand for a predetermined period of time is extracted.

[0027] In the binder mixing process, the supernatant of the extracted dispersion liquid is mixed with a binder. Examples of the binder include silicon, acrylic, natural, and synthetic resins, and are not limited as long as they dissolve in a solvent. An electrode material recycling process may be performed in the electrode formation process described below. The electrode material recycling process includes, for example, an electrode material recovery process for recovering the carbon-based conductive material that is surplus in the electrode formation process, and a redispersion process for dispersing the recovered carbon-based conductive material in a predetermined liquid. The redispersed dispersion liquid may be mixed with a binder in the binder mixing process.

[0028] Through the above treatment, a carbon-based conductive material is obtained.

[0029] [Second inspection process] In the carbon-based conductive material production process, a second inspection process may be performed. The second inspection process is performed, for example, between the supernatant extraction process and the binder mixing process. The second inspection process inspects the dispersion state of the dispersion liquid. The dispersion inspection observes the particle size distribution by a sampling inspection. The method for observing the particle size distribution is not limited, and examples thereof include a method using a microscope, a visualization method using laser light, etc.

[0030] [Electrode formation process] The electrode formation step is a step of forming a pair of electrode layers 2A, 2B on both sides of the dielectric elastomer layer 1. As shown in Fig. 5, the electrode formation step includes a coating process and a drying process.

[0031] In the illustrated example, the coating process includes, but is not limited to, a screen mask mounting process, an electrode material coating process, and a screen mask cleaning process. The electrode material coating process may be, for example, inkjet printing. If the inkjet printing is sufficiently fine and does not require a mask, the coating process may be configured not to include the screen mask mounting process and the screen mask cleaning process.

[0032] The screen mask application process involves applying a screen mask to the stretched elastomer, and optionally applying a primer to the elastomer material or the screen mask.

[0033] In the electrode material application process, a carbon-based conductive material is applied to the elastomer material with a screen mask attached. There are no particular limitations on the specific method of applying the carbon-based conductive material, and the application may be performed by, for example, spray application, squeegee application, spin coating, or the like.

[0034] The screen mask cleaning process removes the carbon-based conductive material adhering to the screen mask after it has been removed from the elastomeric material, for use, for example, in the electrode material recycling process described above.

[0035] In order to form a pair of electrode layers 2A, 2B on both sides of the dielectric elastomer layer 1, the above-mentioned screen mask attachment process, electrode material application process, and screen mask cleaning process may be performed sequentially on one side of the dielectric elastomer layer 1, or at least some of the processes may be performed simultaneously on both sides of the dielectric elastomer layer 1.

[0036] In the drying process, the carbon-based conductive material applied to the elastomer material is dried. There are no particular limitations on the specific method for drying the carbon-based conductive material, and the material may be dried at room temperature or by increasing the temperature.

[0037] Through the electrode formation step, a dielectric elastomer layer 1 having a pair of electrode layers 2A, 2B formed thereon is obtained.

[0038] [Third inspection process] In the electrode formation step, a third inspection step may be performed after the coating process and before the drying process. The third inspection step is a step of inspecting the coating state of the carbon-based conductive material.

[0039] As an example of the third inspection process, the coating thickness of the carbon-based conductive material applied to both sides of the elastomer material is measured. The coating thickness is preferably about 90% to 110% of the specified coating thickness, which is taken as 100%.

[0040] [Fourth inspection process] A fourth inspection step may be performed after the electrode formation step and before the support material attachment step. The fourth inspection step is a step of inspecting the electrical resistance of the pair of electrode layers 2A, 2B.

[0041] In the fourth inspection step, for example, it may be inspected whether there is improper conduction between the pair of electrode layers 2A, 2B formed on both sides of the dielectric elastomer layer 1. The continuity inspection of the pair of electrode layers 2A, 2B is preferably performed at a low voltage that does not damage the elastomer material, for example, and more preferably at the rated voltage for the operation of the dielectric elastomer device A1.

[0042] In the fourth inspection step, the electrical resistance between both end portions may be measured for each of electrode layer 2 A and electrode layer 2 B. The measured electrical resistance value is preferably about 90% to 110% assuming that the specified electrical resistance value is 100%.

[0043] [Support material installation process] The support material attachment step is a step of attaching the dielectric elastomer layer 1 on which the pair of electrode layers 2A, 2B are formed to the support material 3. As shown in Fig. 6, in the illustrated example, the support material attachment step includes, but is not limited to, a support material attachment process and a protective reinforcement process. Furthermore, the order of the support material attachment process and the protective reinforcement process is not limited in any way.

[0044] In the support material attachment process, the dielectric elastomer layer 1 is attached to the support material 3. The support material 3 may have a power supply part (not shown) for applying a voltage to the pair of electrode layers 2A, 2B. In this case, the support material attachment step may include a process for electrically connecting the pair of electrode layers 2A, 2B to the power supply part.

[0045] In the protective and reinforcing treatment, paint, elastomer, etc. are applied to protect or reinforce the entire or part of the dielectric elastomer layer 1. Prior to this application, masking may be performed to cover predetermined areas.

[0046] [Unnecessary part removal process] In the unnecessary part removing step, a part of the dielectric elastomer layer 1 that is not necessary for the operation of the dielectric elastomer device A1 is removed. As shown in Fig. 6, in the illustrated example, the unnecessary part removing step includes, but is not limited to, an unnecessary part removing process and a protective reinforcement process.

[0047] In the unnecessary portion removing process, for example, the portion of the dielectric elastomer layer 1 that protrudes outward from the support material 3 is removed by cutting or the like. The protective reinforcement process is, for example, the same as the protective reinforcement process in the support material mounting step.

[0048] [Fifth inspection process] After the unnecessary portion removing step, a fifth inspection step may be performed. The fifth inspection step corresponds to an initial inspection of the completed dielectric elastomer device A1.

[0049] The fifth inspection step may include the following inspections. For example, the dielectric elastomer layer 1 may be stretched in the movable direction of the dielectric elastomer device A1 to check for damage. Alternatively, the electrical resistance between the power supply part of the support material 3 and the electrode layers 2A and 2B may be measured to check for any error relative to a preset value. Alternatively, an LCR meter may be connected to the pair of electrode layers 2A and 2B to check for any error. The capacitance between the pair of electrode layers 2A, 2B may be measured. Alternatively, the maximum allowable voltage for the dielectric elastomer device A1 may be applied to the pair of electrode layers 2A, 2B to inspect for the presence or absence of dielectric breakdown and insulation resistance.

[0050] Next, the operation of the method for manufacturing a dielectric elastomer device according to the present invention will be described.

[0051] According to this embodiment, the dielectric elastomer device can be manufactured more appropriately.

[0052] The method for manufacturing a dielectric elastomer device according to the present invention is not limited to the above-described embodiment. The specific configuration of the method for manufacturing a dielectric elastomer device according to the present invention can be freely designed in various ways. [Explanation of symbols]

[0053] A1: Dielectric elastomer device 1: Dielectric elastomer layer 2A: Electrode layer 2B: Electrode layer 3: Support material 4: Control section

Claims

[Claim 1] an elastomer stretching step for stretching the elastomeric material to a prescribed length; a carbon-based conductive material producing step of producing a carbon-based conductive material by mixing a dispersion in which a carbon-based conductive filler is dispersed in a liquid with a binder; an electrode forming process including a coating process of coating the carbon-based conductive material on a surface of the elastomer material, and a drying process of drying the coated carbon-based conductive material; a support attachment step of attaching a support to the elastomeric material; A method for manufacturing a dielectric elastomer device, comprising: a step of removing unnecessary portions of the elastomer material, a first inspection step of inspecting a film thickness of the elastomer material after the elastomer stretching step and before the electrode forming step; a second inspection step of inspecting the dispersion state of the dispersion liquid in the carbon-based conductive material producing step; a third inspection step of inspecting a coating state of the carbon-based conductive material after the coating process and before the drying process in the electrode formation step; a fourth inspection step of inspecting an electrical resistance value of the electrode after the electrode forming step and before the support material attaching step; A method for manufacturing a dielectric elastomer device, further comprising at least one of a fifth inspection step of inspecting the operation of the dielectric elastomer device after the unnecessary portion removing step.

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