Flexible sheet electrodes, wearable bioelectrodes, biosensors

Abstract

To provide a flexible sheet electrode which can suppress occurrence of cracks on an electrode end by washing.SOLUTION: A flexible sheet electrode includes a flexible base material, an elastomer electrode layer which is provided on the surface of the flexible base material and contains a conductive filler A and an elastomer A, and an end protective member which covers from at least a part of the end of the elastomer electrode layer to at least a part of the surface of the flexible base material, and is made of an elastomer, wherein the end protective member has higher flexibility than that of the elastomer electrode layer.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a flexible sheet electrode, a wearable biometric electrode, and a biosensor. Sa and the like.

Background Art

[0002] Various developments have been made on sheet electrodes so far. As this type of technology, for example, the technology described in Patent Document 1 is known. Patent Document 1 describes a stretchable wiring board having a stretchable wiring portion including a conductive material and a resin binder formed on a stretchable base material (FIG. 2, paragraph 0024, etc.).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the washability of the stretchable wiring board of Patent Document 1 has not been sufficiently studied. As a result of the study by the present inventor, it has been found that there is room for improvement in that cracks may occur at the end of the stretchable wiring portion due to washing in the structure of the stretchable wiring portion as described above.

Means for Solving the Problems

[0005] As a result of further study by the present inventor, it has been found that when a flexible sheet electrode having an elastomer electrode layer formed on a flexible base material is repeatedly washed, cracks occur at the interface between the electrode layer and the base material at the end of the elastomer electrode layer. This is presumably because there is a difference in the ease of stretching between the elastomer electrode layer and the flexible base material, so stress concentration occurs at the interface between the two during washing, resulting in cracks as described above. Based on these findings, we conducted thorough research and discovered that by using an elastomer edge protection member, which is more flexible than the elastomer electrode layer, to cover the bonding interface between the elastomer electrode layer and the flexible substrate, crack formation at the electrode edges of the flexible sheet electrode after washing can be suppressed, thus completing the present invention.

[0006] According to the present invention, Flexible substrate and An elastomer electrode layer containing conductive filler A and elastomer A is provided on the surface of the flexible substrate, The system includes an elastomer edge protection member that covers at least a portion of the edge of the elastomer electrode layer to at least a portion of the surface of the flexible substrate, A flexible sheet electrode in which the end protection member is configured to be more flexible than the elastomer electrode layer.

[0007] Furthermore, according to the present invention, A wearable bioelectrode is provided, which includes the flexible sheet electrode described above.

[0008] Furthermore, according to the present invention, A biosensor equipped with the above-mentioned wearable bioelectrode is provided.

[0009] Furthermore, according to the present invention, A step of forming a sheet-like film by applying a conductive paste for an elastomer electrode layer containing conductive filler A and elastomer A onto the surface of a flexible substrate, The process includes the step of applying an edge protection paste to cover at least a portion of the edge of the sheet-like film and at least a portion of the surface of the flexible substrate, and then heat-treating it to form an elastomer electrode layer and an edge protection member, The paste for the end protection member is a conductive paste B containing conductive filler B and elastomer B in a quantity less than the content of conductive filler A contained in the paste, or an insulating paste containing elastomer C but no conductive filler. A method for manufacturing a flexible sheet electrode is provided. [Effects of the Invention]

[0010] The present invention provides a flexible sheet electrode that can suppress crack formation at the electrode end due to washing, a wearable bioelectrode and biosensor using the same, or a method for manufacturing a flexible sheet electrode. [Brief explanation of the drawing]

[0011] [Figure 1] This figure schematically shows an example of the configuration of the flexible sheet electrode of this embodiment ((a) cross-sectional view, (b) top view). [Figure 2] This is a schematic cross-sectional view showing an example of a modified flexible sheet electrode. [Figure 3] This is a schematic top view showing an example of the configuration of a wearable bioelectrode according to this embodiment. [Figure 4] This is a cross-sectional view taken along the arrow BB in Figure 3. [Figure 5] This is a schematic diagram illustrating an example of the configuration of the biosensor in this embodiment. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described below with reference to the drawings. In all drawings, similar components are denoted by the same reference numerals, and their descriptions are omitted as appropriate. Also, the drawings are schematic diagrams and do not correspond to the actual dimensional ratios.

[0013] The outline of the flexible sheet electrode of this embodiment will be described.

[0014] The flexible sheet electrode of this embodiment comprises a flexible substrate, an elastomer electrode layer provided on the surface of the flexible substrate containing a conductive filler A and an elastomer A, and an elastomer edge protection member covering at least a portion of the edge of the elastomer electrode layer to at least a portion of the surface of the flexible substrate, wherein the edge protection member is configured to be more flexible than the elastomer electrode layer.

[0015] According to the inventors' findings, it has been found that by using an elastomer edge protection member, which is more flexible than the elastomer electrode layer, to cover the bonding interface between the elastomer electrode layer and the flexible substrate, it is possible to suppress the occurrence of cracks at the electrode edges of the flexible sheet electrode after washing.

[0016] The detailed mechanism is not clear, but it is speculated to be as follows: In flexible sheet electrodes, if there is a difference in flexibility, such as ease of stretching, between the flexible base material and the elastomer electrode layer, stress will concentrate at the interface between the two during stretching or bending, making it easier for cracks to develop starting from this point. In particular, during washing, the load is greater at the edges of the sheet-like elastomer electrode layer than at the center, resulting in greater strain (stretching and deformation). Therefore, it is presumed that by using an elastomer end protection member, which is more flexible than the elastomer electrode layer, to cover the bonding interface between the elastomer electrode layer and the flexible substrate, the end protection member can function as a suitable buffer, thereby suppressing the occurrence of stress concentration as described above, and thus suppressing the occurrence of cracks at the electrode ends due to washing.

[0017] According to this embodiment, a washable, flexible sheet electrode can be realized.

[0018] Flexible sheet electrodes can be applied to various uses, one of which is wearable bioelectrodes. The wearable bioelectrode of this embodiment is equipped with the flexible sheet electrode described above.

[0019] Wearable bioelectrodes can detect electrical potential fluctuations from living organisms, such as heart rate, muscle activity, and nervous system activity. For example, a wearable bioelectrode may be configured to measure at least one of the following bioelectric potentials: electrocardiogram, electromyogram, and skin potential.

[0020] According to this embodiment, a stretchable and / or bendable wearable bioelectrode can be realized. Such wearable bioelectrodes suppress wire breakage in the flexible sheet electrode even when the substrate is deformed, such as by stretching or bending, enabling stable measurement of biopotential. Furthermore, even when the substrate is deformed, delamination of the flexible sheet electrode from the flexible substrate is suppressed, and mutual adhesion is maintained.

[0021] Wearable bioelectrodes can be used as wearable devices that can be attached to either the body or clothing. Due to their elasticity, such wearable bioelectrodes can conform to the surface shape and movements of the body. In this case, the wearable bioelectrode may be attached directly to the body or to the body via a body-attaching component (clothing). Clothing with wearable bioelectrodes may, for example, have a configuration in which the wearable bioelectrode is sewn into the clothing, or a configuration in which the wearable bioelectrode is used as part of the clothing.

[0022] Wearable bioelectrodes can be further equipped with connectors and electronic components to form biosensors that can connect to external devices. These biosensors are wearable. By analyzing bioelectric potentials such as electrocardiograms detected by the biosensors, biosignal measurement systems tailored to various applications can be constructed.

[0023] Such wearable bioelectrodes, biosensors using them, and biosignal measurement systems are expected to be usable in a variety of settings, including physical diagnosis, health management, fitness, rehabilitation, and elderly care.

[0024] The configuration of the flexible sheet electrode and the wearable bioelectrode of this embodiment will be described in detail below.

[0025] <Flexible Sheet Electrode> Figure 1 is a top view showing an example of the configuration of the flexible sheet electrode 1. Figure 1(a) is a cross-sectional view of (b)AA of the flexible sheet electrode 1, and (b) is a top view of the flexible sheet electrode 1. Figure 2 is a cross-sectional view showing an example of deformation of the flexible sheet electrode 1.

[0026] The flexible sheet electrode 1 comprises a flexible base material 10, an elastomer electrode layer 2, and an edge protection member 70.

[0027] The flexible base material 10 is not particularly limited as long as it is a base material that can be stretched and / or bent, but for example it may be composed of a fibrous base material, a porous elastomer base material, or an elastomer base material. As the elastomer base material, one containing an insulating elastomer as described later may be used.

[0028] Examples of fiber structural materials for fiber base materials include natural fibers such as plant fibers and animal fibers; and chemical fibers such as inorganic fibers, regenerated fibers, semi-synthetic fibers, and synthetic fibers. These may be used individually or in combination of two or more types. Among these, from the viewpoint of durability, chemical fibers may be used, as may synthetic fibers such as acrylic, polyester, nylon, and polyurethane.

[0029] The fibrous substrate can be any known fibrous substrate, but it may be composed of either an insulating material or a conductive material, or both, for example.

[0030] The lower limit of the basis weight of the fiber base material is, for example, 10 g / m². 2 Preferably 20 g / m² 2 Above, a comfortable 30g / m 2 That concludes the explanation. This will increase the mechanical strength. On the other hand, the upper limit for the basis weight of the fiber base material is, for example, 500 g / m². 2 Preferably 400 g / m² 2 More preferably, 350 g / m² 2The following is the result: This helps to suppress the decrease in flexibility. It also allows for an increase in the degree of impregnation of the conductive elastomer layer.

[0031] The structure of the fibrous base material is not limited, but from the viewpoint of flexibility, woven or knitted fabrics may be used.

[0032] The upper limit of the thickness of the flexible substrate 10 can be set according to the application, for example, it may be 10 mm or less, preferably 1 mm or less, but more preferably 600 μm or less from the viewpoint of wearable device applications. By setting it to 600 μm or less, a thin film sheet-like wearable bioelectrode can be realized. The lower limit of the thickness of the flexible substrate 10 is, from the viewpoint of mechanical strength, for example, 10 μm or more, preferably 50 μm or more, and more preferably 100 μm or more.

[0033] The elastomer electrode layer 2 comprises a conductive elastomer layer 20 containing conductive filler A and elastomer A on its surface side. The surface of the elastomer electrode layer 2 is the exposed surface that comes into direct contact with the body and serves as the measurement surface for measuring biopotential.

[0034] As shown in Figure 1(a), the elastomer electrode layer 2 may have a laminate 23 provided on the surface of the flexible substrate 10 in a cross-sectional view in the thickness direction of the flexible sheet electrode 1, but it may also be configured to have a laminate 23 and an impregnation layer 21, as shown in Figures 2(a) and (b). The elastomer electrode layer 2 may have one or more other layers in the laminate 23 and / or the impregnation layer 21, provided that a conductive elastomer layer 20 is formed on the surface side. For example, as shown in Figure 2(a), the elastomer electrode layer 2 may have a conductive elastomer layer 20 and an insulating elastomer layer 60a in the laminate 23 and 60b in the impregnation layer 21, or as shown in Figure 2(b), the laminate 23 may have a conductive elastomer layer 20a, and the impregnation layer 21 may have a conductive elastomer layer 20b and an insulating elastomer layer 60. Note that by forming at least a part of the elastomer electrode layer 2 with insulating elastomer layers 60, 60a, and 60b, the flexibility of the entire flexible sheet electrode 1 can be improved.

[0035] As shown in Figure 1(b), the elastomer electrode layer 2 is configured in a sheet shape, and when viewed from the top surface direction of the flexible sheet electrode 1, its top view shape may be, for example, a square shape, a circular shape, an elliptical shape, or other polygonal shapes. In this specification, "sheet-like" means that the thickness of the conductive elastomer layer 20 is D (mm), and the area of ​​one surface 22 of the conductive elastomer layer 20 as viewed from above is S (mm). 2 When this is the case, S and D are, for example, 50 ≤ S / D, preferably 200 ≤ S / D, more preferably 400 ≤ S / D. The upper limit of S / D can be set according to the measurement site of the subject and is not particularly limited, but for example, S / D ≤ 10 7 But that's fine.

[0036] The end protection member 70 is configured to be more flexible than the elastomer electrode layer 2. As an indicator of flexibility, for example, the tensile modulus, such as the 100% modulus, can be used. A smaller modulus indicates higher flexibility. Other indicators that can be used include elongation (%), which represents the elongation rate to fracture, and hardness. Generally, a larger elongation rate or lower hardness indicates higher flexibility of the material.

[0037] The end protection member 70 may be composed of a conductive elastomer containing conductive filler B and elastomer B in a quantity less than the amount of conductive filler A contained in the elastomer electrode layer 2, or it may be composed of an insulating elastomer containing elastomer C but no conductive filler. By controlling the amount of filler in this way, an end protection member 70 with higher flexibility than the elastomer electrode layer 2 can be realized.

[0038] The elongation rate of the elastomer electrode layer 2 is, for example, 10% or more, preferably 20% or more, and more preferably 50% or more. The elongation rate refers to the ratio of elongation that can be stretched in a predetermined direction while maintaining a state of not breaking. In this specification, the predetermined direction may be, for example, the direction in which the length of the elastomer electrode layer 2 is maximized in the top view of Figure 1, or, if the top view shape is rectangular, the diagonal direction may be adopted. On the other hand, the elongation rate of the end protection member 70 is, for example, 1.1 times or more, preferably 1.5 times or more, the elongation rate of the elastomer electrode layer 2.

[0039] The 100% modulus of the conductive cured product obtained by curing the conductive paste constituting the conductive elastomer layer 20 during a tensile test is defined as M1, and the 100% modulus of the end protection member 70 during a tensile test is defined as M2. M1 and M2 are configured such that, for example, 0.1 ≤ M2 / M1 ≤ 3.0. The lower limit of M2 / M1 may be, for example, 0.1 or more, preferably 0.2 or more, and more preferably 0.3 or more. The upper limit of M2 / M1 is, for example, 3.0 or less, preferably 2.8 or less, and more preferably 2.5 or less. By setting the lower and upper limits of M2 / M1 within this range, a sufficient crack suppression effect can be achieved.

[0040] The end protection member 70 is configured to cover the joint between the flexible base material 10 and the elastomer electrode layer 2 in one cross-sectional view of the flexible sheet electrode 1. Specifically, it is configured to cover at least a portion of the end of the elastomer electrode layer 2 from a portion of the surface of the flexible base material 10. The end protection member 70 may cover part or all of the side surface of the end of the conductive elastomer layer 20 from a part of the surface of the flexible base material 10, and may also be configured to cover up to a part of the upper surface of the end. In other words, the end protection member 70 may be configured to cover the upper and side surfaces of the end of the elastomer electrode layer 2 in contact with it. This improves the adhesion between the elastomer electrode layer 2 and the end protection member 70.

[0041] When the flexible sheet electrode 1 is viewed perpendicular to its surface, let S1 be the surface area of ​​the elastomer electrode layer 2, and S2 be the area of ​​the portion of the end protection member 70 that covers the surface of the elastomer electrode layer 2. S1 and S2 are configured such that, for example, 0.03 ≤ S2 / S1 ≤ 0.7. The lower limit of S2 / S1 is, for example, 0.03 or higher, preferably 0.04 or higher, and more preferably 0.05 or higher. This allows for sufficient crack suppression. The upper limit of S2 / S1 is, for example, 0.7 or less, preferably 0.5 or less, and more preferably 0.3 or less. This makes it possible to improve durability without impairing electrode performance.

[0042] When viewing the flexible sheet electrode 1 in cross-section in the lamination direction, the thickness of the elastomer electrode layer 2 is denoted as H1, and the thickness of the end protection member 70 is denoted as H2. H1 and H2 are configured such that, for example, 0.3 ≤ H2 / H1 ≤ 0.8. The lower limit of the H2 / H1 ratio is, for example, 0.3 or higher, preferably 0.4 or higher, and more preferably 0.5 or higher. This allows for sufficient crack suppression. The upper limit of the H2 / H1 ratio is, for example, 0.8 or less, preferably 0.78 or less, and more preferably 0.75 or less. This maintains electrode adhesion to the skin and improves electrode performance.

[0043] Furthermore, resistivity measurements, such as surface resistivity, may also be performed by measuring the surface of the elastomer electrode layer 2 using the four-probe method.

[0044] An example of a method for manufacturing the flexible sheet electrode 1 includes the steps of: applying a conductive paste for an elastomer electrode layer containing a conductive filler A and an elastomer A onto the surface of the flexible sheet electrode 1 to form a sheet-like film; and applying a paste for an edge protection member so as to cover at least a portion of the edges of the sheet-like film and at least a portion of the surface of the flexible sheet electrode 1, and then heat-treating it to form an elastomer electrode layer 2 and an edge protection member 70.

[0045] The specific procedure for manufacturing the flexible sheet electrode 1 described above using screen printing is as follows. First, a support is placed on the workbench, and the flexible substrate 10 is placed on the support. Next, a mask having a predetermined opening pattern shape is placed on the flexible substrate 10. Next, a conductive paste for the elastomer electrode layer is applied to the flexible substrate 10 via a mask using a squeegee to form a sheet-like film. The sheet-like film may be dried if necessary. Next, a paste for edge protection is applied with a squeegee to the periphery of the sheet-like film in a top view, using a mask as a guide, to form a surrounding film. Subsequently, the sheet-like film and the enclosure-like film are subjected to heat treatment, and if the pastes of both contain a silicone rubber-based curable composition, a curing treatment is performed. For example, the curing temperature can be set to 160°C to 220°C, and the curing time to 1 to 3 hours. Subsequently, the flexible substrate 10 support is separated to obtain the flexible sheet electrode 1. Furthermore, the thickness of the mask, the number of layers of the mask, the number of coatings, and the solid content concentration in the paste can be adjusted as needed.

[0046] The elastomer electrode layer 2 can be formed using a conductive paste for elastomer electrode layers containing conductive filler A and elastomer A. That is, an example of the elastomer electrode layer 2 is composed of a printed layer of conductive paste. Therefore, a flexible sheet electrode with excellent design flexibility for sheet electrode design can be provided.

[0047] Furthermore, the end protection member 70 can also be formed by a printing method using an end protection member paste, similar to the elastomer electrode layer 2. The paste for the end protection member can be a conductive paste B containing conductive filler B and elastomer B in a smaller amount than the amount of conductive filler A contained in the conductive paste for the elastomer electrode layer, or an insulating paste containing elastomer C but no conductive filler.

[0048] By forming the elastomer electrode layer 2 and the conductive elastomer layer 20 from a paste containing the same type of elastomer, such as the same type of silicone rubber, it becomes possible to form them without an interface between them. In other words, the flexible sheet electrode 1 may have a seamless interface between the elastomer electrode layer 2 and the end protection member 70. This further improves the adhesion between the two.

[0049] <Wearable Bioelectrodes> Figure 3 is a top view showing an example of the configuration of the wearable bioelectrode 100. Figure 4 is a cross-sectional view of BB in Figure 3. The wearable bioelectrode 100 comprises a flexible sheet electrode 1 having a flexible substrate 10 and an elastomer electrode layer 2 including a conductive elastomer layer 20.

[0050] The wearable bioelectrode 100 can detect bioelectrical signals generated from biological activities such as the heart, muscles, skin, and nerves by having one surface 22 of the conductive elastomer layer 20 follow the body of the subject. When the wearable bioelectrode 100 has multiple conductive elastomer layers 20 in the in-plane direction of the flexible substrate 10, it can be suitably used as an electrode for measuring electrocardiogram waveforms.

[0051] Subjects include humans, non-human animals, and others.

[0052] The wearable bioelectrode 100 can be used as a simple and reusable dry sensor, rather than a wet sensor that requires the application of gel to the measurement area of ​​the subject.

[0053] The flexible substrate 10 has an electrode-forming region on which a conductive elastomer layer 20 is formed when viewed from above. In this electrode-forming region, the flexible substrate 10 and the conductive elastomer layer 20 adhere closely together when not stretched or when stretched, thereby increasing the overall mechanical strength of the wearable bioelectrode 100.

[0054] Furthermore, the flexible substrate 10 may have an electrode-free region around the electroformed region where the conductive elastomer layer 20 is not formed. Attachments such as sewing threads or snap buttons for attachment to clothing can be attached to this electrode-free region. Alternatively, when the wearable bioelectrode 100 is wrapped around the body, such as the wrist or ankle, the electrode-free regions of the flexible substrate 10 may be overlapped in the thickness direction to secure it to the body.

[0055] An example of the flexible substrate 10 is shown in Figure 3, in which at least a part of it, for example, the main body 12, has a band shape that can be wrapped around the body. Such a wearable bioelectrode 100 has a structure suitable for a band-type bioelectrode that can be wrapped around a part of the body, such as the wrist or ankle.

[0056] Furthermore, the band-type flexible base material 10 in Figure 3 may have a main body 12 and an expansion portion 14 that protrudes in the in-plane direction of the main body 12. Even when the main body 12 is deformed into a ring structure or the like, deformation of the expansion portion 14 is suppressed. Therefore, connection failures at the external connection portion 30 attached to the expansion portion 14 can be suppressed.

[0057] The conductive elastomer layer 20 is configured in a sheet shape and has an exposed surface that comes into direct contact with the body.

[0058] The conductive elastomer layer 20 comes into contact with the body when the wearable bioelectrode 100 is in use and can conform well to the contact surface, taking into account the surface shape and deformation of the body.

[0059] The wearable bioelectrode 100 may be configured to be connected to the outside by a conductive elastomer layer 20, or it may be configured to be connected to a connecting portion 26, which is a separate component electrically connected to the conductive elastomer layer 20. As shown in Figure 3, this connecting portion 26 may be configured to be electrically connected to the conductive elastomer layer 20 via an expandable wire 24.

[0060] The conductive elastomer layer 20, the stretchable wiring 24, and the connecting portion 26 are made of the same / different conductive elastomer, preferably the same conductive elastomer.

[0061] Each component of the conductive elastomer layer 20 may be composed of a printed layer formed by a printing method using a conductive paste. In this case, each component, including the conductive elastomer layer 20, the stretchable wiring 24, and the connecting portion 26, may be seamlessly connected to one another.

[0062] The external connection section 30 can send bioelectric signals detected through the conductive elastomer layer 20 to external electronic components, etc.

[0063] The wearable bioelectrode 100 shown in Figure 3 includes an external connection part 30. The external connection portion 30 is provided on the flexible substrate 10 opposite to the conductive elastomer layer 20. For example, the external connection portion 30 in Figure 2 is formed on the other surface 13 of the flexible substrate 10. This prevents the external connection portion 30 from coming into contact with the body together with the conductive elastomer layer 20 when the wearable bioelectrode 100 is in use, thereby suppressing interference with the detection of bioelectrical signals.

[0064] The external connection part 30 is not particularly limited as long as it is configured to be electrically connected to the conductive elastomer layer 20, but it is made of a conductive material such as a metal material or a conductive elastomer.

[0065] The shape of the external connection part 30 is not particularly limited, but it may have a connector that can be connected to electronic components or a structure that facilitates wiring.

[0066] An example of the external connection part 30 may be a metal snap button. The external connection part 30 in Figure 4 is a male snap button and is fixed to the flexible base material 10 using a metal mounting plate 32 and mounting pin 34. By fixing the flexible base material 10 by sandwiching it between the external connection part 30 and the mounting plate 32, misalignment of the fixing position of the external connection part 30 can be suppressed. The mounting pin 34 contacts a part of the conductive elastomer layer 20, for example, the connection part 26, thereby enabling electrical connection between the conductive elastomer layer 20 and the external connection part 30.

[0067] Furthermore, part or all of the mounting plate 32 in Figure 4 is covered with an insulating protective layer 52. The insulating protective layer 52 prevents contact between the mounting plate 32 and the body. The insulating protective layer 52 may be made of an insulating material, for example, an insulating elastomer such as silicone rubber.

[0068] The biosensor of this embodiment will now be described.

[0069] Depending on the application, the biosensor comprises one wearable bioelectrode 100 or two or more wearable bioelectrodes 100. The biosensor may be directly attached to the body, or it may be attached to a body attachment component such as clothing.

[0070] The biosensor includes electronic components that can be electrically connected to the wearable bioelectrode 100 via an external connection part 30.

[0071] Various known electronic components can be used depending on the application, but examples include amplifiers, AD converters, CPUs, memory, communication circuits, wireless communication units, analog filters, capacitors, resistors, and batteries. One or more of these may be modularized on a circuit board. This allows the biosensor to be used as a wearable device. Furthermore, other sensors such as acceleration sensors, temperature sensors, and pressure sensors may be used in combination as electronic components.

[0072] Figure 5 is a diagram illustrating an example of the configuration of the biosensor 200. The biosensor 200 in Figure 5 comprises a wearable bioelectrode 100, a connector 210, a cable 220, a sensor module 230, and a computer 240.

[0073] The connector 210 has a structure that allows it to be electrically coupled to the external connection part 30 of the wearable bioelectrode 100, and may have, for example, a female snap button. Cable 220 electrically connects connector 210 to the electronic components, sensor module 230 and computer 240. The sensor module 230 can be used with an ECG sensor module when measuring electrocardiogram waveforms. The sensor module 230 has an electrical circuit that suppresses interference from external RF sources, line frequencies, and electrical noise, and can suppress noise when measuring bioelectrical signals. Computer 240 can acquire bioelectrical signals and generate and output waveforms of bioelectric potentials such as surface electromyography, electrocardiogram, skin potential, and electroencephalography. Computer 240 may also use a single-board computer consisting of a printed circuit board equipped with a CPU, peripheral components, input / output interfaces, connectors, etc.

[0074] The biosignal measurement system of this embodiment will now be described. A biosignal measurement system is equipped with a biosensor. A biosignal measurement system may be a system (measuring device) that displays, analyzes, or stores data received from a biosensor.

[0075] The materials for the conductive elastomer layer 20, the insulating elastomer layer 60, and the end protection member 70 will be described below.

[0076] The conductive elastomer layers 20, 20a, and 20b in the flexible sheet electrode 1 may each be composed of a conductive elastomer. The insulating elastomer layers 60, 60a, and 60b in the flexible sheet electrode 1 may each be composed of an insulating elastomer. The end protection member 70 in the flexible sheet electrode 1 may be made of a conductive elastomer or an insulating elastomer. The insulating elastomer and the conductive elastomer may contain the same or different elastomer materials. Conductive filler A and conductive filler B may be the same or different, and elastomer A, elastomer B, and elastomer C may each be the same or different.

[0077] Insulating elastomers can include, for example, silicone rubber, urethane rubber, fluororubber, nitrile rubber, acrylic rubber, styrene rubber, chloroprene rubber, ethylene propylene rubber, and the like. Among these, the elastomer includes one or more thermosetting elastomers (elastomer materials) selected from the group consisting of silicone rubber, urethane rubber, and fluororubber. An insulating elastomer may consist of an elastomer material alone, or it may be composed of an elastomer material and a non-conductive filler. An example of an insulating elastomer includes silicone rubber, preferably silicone rubber and a non-conductive filler. Among elastomers, silicone rubber is chemically stable and also has excellent mechanical strength. Among these, from a hygienic standpoint, it is preferable to use silicone rubber, which has high biocompatibility, as the elastomer material.

[0078] Conductive elastomers can include, for example, silicone rubber, urethane rubber, fluororubber, nitrile rubber, acrylic rubber, styrene rubber, chloroprene rubber, ethylene propylene rubber, and the like. Among these, the elastomer includes one or more thermosetting elastomers (elastomer materials) selected from the group consisting of silicone rubber, urethane rubber, and fluororubber, and a conductive filler. A preferred example of a conductive elastomer includes silicone rubber and a conductive filler. This enhances the elasticity and conductivity of the conductive elastomer.

[0079] At least one, preferably both, of the insulating elastomer and the conductive elastomer may contain a non-conductive filler. Known materials can be used as the non-conductive filler, such as silica particles, silicone rubber particles, or talc. Among these, silica particles may also be included.

[0080] The conductive filler may include, for example, one or more selected from the group consisting of powdered or fibrous metal-based fillers, carbon-based fillers, metal oxide fillers, and metal-plated fillers. Among these, a metal-based filler such as silver powder may be used as the conductive filler.

[0081] The conductive elastomer may further contain non-conductive fillers in addition to the conductive fillers. This can enhance the mechanical properties of the conductive elastomer.

[0082] A specific example is that at least two or all of the conductive elastomer layer 20, the insulating elastomer layer 60, and the end protection member 70 may be configured to contain the same elastomer material. For example, the elastomer electrode layer 2 and the end protection member 70 may contain silicone rubber. This can improve the adhesion between the two. Furthermore, the elastomer electrode layer 2 and / or the end protection member 70 may also contain a non-conductive filler. This can improve mechanical strength. Furthermore, the elastomer electrode layer 2, i.e., filler A, may contain silver powder as a conductive filler, preferably in the form of flake-shaped silver powder. This can improve conductivity and, moreover, stretch conductivity. Furthermore, the elastomer electrode layer 2 may also contain silver powder and silica particles as a non-conductive filler. This improves the stretchability and durability of the elastomer electrode layer 2.

[0083] In this specification, "containing the same elastomer material" means that each contains at least one of the same type of elastomer material from among the types of thermosetting elastomers exemplified above. Furthermore, if the same silicone rubber is included, this silicone rubber may be composed of a cured product of a silicone rubber-based curable composition containing a vinyl group-containing organopolysiloxane. From the viewpoint of mechanical strength and other factors, it is preferable that the insulating elastomer layer 60 and / or the conductive elastomer layer 20 contain silicone rubber.

[0084] The insulating elastomer may be composed of a cured product of a silicone rubber-based curable composition containing a vinyl group-containing organopolysiloxane. The conductive elastomer may be composed of a conductive filler and a cured product of a silicone rubber-based curable composition containing a vinyl group-containing organopolysiloxane.

[0085] The components of the silicone rubber-based curable composition are described in detail below.

[0086] In this specification, "containing the same silicone rubber" means that the silicone rubber-based curable composition contains at least the same type of vinyl group-containing linear organopolysiloxane, and may further contain one or more selected from the group consisting of the same type of crosslinking agent, the same type of nonconductive filler, the same type of silane coupling agent, and the same type of catalyst.

[0087] A linear organopolysiloxane containing the same type of vinyl group is defined as one that contains at least the same vinyl group as a functional group and has a linear structure, even if the amount of vinyl group in the molecule, the molecular weight distribution, or the amount added differs.

[0088] Similar crosslinking agents only need to have a common structure, such as a linear or branched structure, and may have different molecular weight distributions and functional groups, as well as different amounts added.

[0089] Non-conductive fillers of the same type only need to have at least common constituent materials, and may differ in particle size, specific surface area, surface treatment agent, or the amount of such agent added.

[0090] Similar silane coupling agents only need to have at least one common functional group; other functional groups in the molecule and the amount added may differ.

[0091] Catalysts of the same type only need to have at least common constituent materials; they may contain different compositions, and the amounts of these compositions added may differ.

[0092] A silicone rubber-based curable composition comprising the same silicone rubber may further contain one or more different types selected from the group consisting of vinyl group-containing linear organopolysiloxanes, crosslinking agents, nonconductive fillers, silane coupling agents, and catalysts.

[0093] The silicone rubber-based curable composition of this embodiment may contain a vinyl group-containing organopolysiloxane (A). The vinyl group-containing organopolysiloxane (A) is a polymer that forms the main component of the silicone rubber-based curable composition of this embodiment.

[0094] The vinyl group-containing organopolysiloxane (A) may include a vinyl group-containing linear organopolysiloxane (A1) having a linear structure.

[0095] The above vinyl group-containing linear organopolysiloxane (A1) has a linear structure and contains vinyl groups, which serve as crosslinking points during curing.

[0096] The vinyl group content of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but it is preferable that it has two or more vinyl groups in the molecule and that the content is 15 mol% or less. This optimizes the amount of vinyl groups in the vinyl group-containing linear organopolysiloxane (A1) and ensures the formation of a network with the components described later.

[0097] In this specification, "~" indicates that the upper and lower limits are included unless otherwise specified.

[0098] In this specification, the vinyl group content refers to the mole percent of vinyl group-containing siloxane units when the total number of units constituting the vinyl group-containing linear organopolysiloxane (A1) is considered to be 100 mol%. However, it is assumed that there is one vinyl group per vinyl group-containing siloxane unit.

[0099] Furthermore, the degree of polymerization of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but is preferably in the range of 1000 to 10000, and more preferably in the range of 2000 to 5000. The degree of polymerization can be determined, for example, by the number-average degree of polymerization (or number-average molecular weight) in terms of polystyrene in GPC (gel permeation chromatography) using chloroform as the developing solvent.

[0100] Furthermore, the specific gravity of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but is preferably in the range of about 0.9 to 1.1.

[0101] By using the vinyl group-containing linear organopolysiloxane (A1) having a degree of polymerization and a specific gravity within the above ranges, it is possible to improve the heat resistance, flame retardancy, chemical stability, etc. of the resulting silicone rubber.

[0102] The vinyl group-containing linear organopolysiloxane (A1) preferably has a structure represented by the following formula (1).

[0103]

Chemical formula

[0104] In formula (1), R 1 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group having 1 to 10 carbon atoms, or a hydrocarbon group combining these. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, etc., and among them, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, a butenyl group, etc., and among them, a vinyl group is preferable. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group, etc.

[0105] Also, R 2 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group having 1 to 10 carbon atoms, or a hydrocarbon group combining these. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, etc., and among them, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, a butenyl group. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

[0106] Also, R 3This group is a substituted or unsubstituted alkyl group, aryl group, or hydrocarbon group having 1 to 8 carbon atoms. Examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. An example of an aryl group having 1 to 8 carbon atoms is the phenyl group.

[0107] Furthermore, R in equation (1) 1 and R 2 Examples of substituents include methyl groups and vinyl groups, and R 3 Examples of substituents include methyl groups.

[0108] Note that in equation (1), multiple R 1 These are independent of each other, and may be different from each other or the same. Furthermore, R 2 , and R 3 The same applies to this matter.

[0109] Furthermore, m and n are the number of repeating units constituting the vinyl group-containing linear organopolysiloxane (A1) represented by formula (1), where m is an integer from 0 to 2000 and n is an integer from 1000 to 10000. Preferably, m is from 0 to 1000 and n is from 2000 to 5000.

[0110] Furthermore, a specific structure of the vinyl group-containing linear organopolysiloxane (A1) represented by formula (1) is, for example, the one represented by the following formula (1-1).

[0111] [ka]

[0112] In formula (1-1), R 1 and R 2 Each of these is independently either a methyl group or a vinyl group, and at least one of them is a vinyl group.

[0113] The vinyl group-containing linear organopolysiloxane (A1) may include a first vinyl group-containing linear organopolysiloxane (A1-1) having two or more vinyl groups in the molecule and containing 0.4 mol% or less. The amount of vinyl groups in the first vinyl group-containing linear organopolysiloxane (A1-1) may be 0.1 mol% or less.

[0114] Furthermore, the vinyl group-containing linear organopolysiloxane (A1) may contain a first vinyl group-containing linear organopolysiloxane (A1-1) and a second vinyl group-containing linear organopolysiloxane (A1-2) having a vinyl group content of 0.5 to 15 mol%.

[0115] By combining a first vinyl group-containing linear organopolysiloxane (A1-1) and a second vinyl group-containing linear organopolysiloxane (A1-2) with a high vinyl group content, the vinyl groups can be unevenly distributed, allowing for more effective formation of crosslink density variations within the crosslinking network of the silicone rubber. As a result, the tear strength of the silicone rubber can be more effectively increased.

[0116] Specifically, it is preferable to use, for example, a first vinyl group-containing linear organopolysiloxane (A1-1) having two or more units in the molecule where R1 is a vinyl group and / or R2 is a vinyl group in the above formula (1-1), and containing 0.4 mol% or less of these units, and a second vinyl group-containing linear organopolysiloxane (A1-2) containing 0.5 to 15 mol% of units where R1 is a vinyl group and / or R2 is a vinyl group.

[0117] Furthermore, the first vinyl group-containing linear organopolysiloxane (A1-1) preferably has a vinyl group content of 0.01 to 0.2 mol%. Also, the second vinyl group-containing linear organopolysiloxane (A1-2) preferably has a vinyl group content of 0.8 to 12 mol%.

[0118] Furthermore, when a first vinyl group-containing linear organopolysiloxane (A1-1) and a second vinyl group-containing linear organopolysiloxane (A1-2) are combined, the ratio of (A1-1) to (A1-2) is not particularly limited, but for example, a weight ratio of (A1-1):(A1-2) of 50:50 to 95:5 is preferred, and a weight ratio of 80:20 to 90:10 is more preferred.

[0119] Furthermore, the first and second vinyl group-containing linear organopolysiloxanes (A1-1) and (A1-2) may be used individually or in combination of two or more types.

[0120] Furthermore, the vinyl group-containing organopolysiloxane (A) may also include a vinyl group-containing branched organopolysiloxane (A2) having a branched structure.

[0121] <<Organohydrogenpolysiloxane (B)>> The silicone rubber-based curable composition of this embodiment may contain organohydrogenpolysiloxane (B). Organohydrogenpolysiloxanes (B) are classified into linear organohydrogenpolysiloxanes (B1) having a linear structure and branched organohydrogenpolysiloxanes (B2) having a branched structure, and may include either one or both of these.

[0122] Linear organohydrogenpolysiloxane (B1) is a polymer having a linear structure and a structure in which hydrogen is directly bonded to Si (≡Si-H), and undergoes a hydrosilylation reaction with vinyl groups of vinyl group-containing organopolysiloxane (A), as well as vinyl groups of components blended into silicone rubber-based curable compositions, thereby crosslinking these components.

[0123] The molecular weight of the linear organohydrogenpolysiloxane (B1) is not particularly limited, but for example, it is preferable that the weight-average molecular weight is 20,000 or less, and more preferably 1,000 or more and 10,000 or less.

[0124] The weight-average molecular weight of linear organohydrogenpolysiloxane (B1) can be measured, for example, by converting it to polystyrene equivalent in GPC (gel permeation chromatography) using chloroform as the developing solvent.

[0125] Furthermore, it is preferable that the linear organohydrogenpolysiloxane (B1) does not typically have vinyl groups. This effectively prevents the crosslinking reaction from proceeding within the linear organohydrogenpolysiloxane (B1) molecule.

[0126] As the linear organohydrogenpolysiloxane (B1) described above, one having the structure represented by the following formula (2) is preferably used.

[0127] [ka]

[0128] In formula (2), R 4 The group is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, a hydrocarbon group formed by combining these groups, or a hydride group, all having 1 to 10 carbon atoms. Examples of alkyl groups having 1 to 10 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. Examples of alkenyl groups having 1 to 10 carbon atoms include vinyl, allyl, and butenyl groups. An example of an aryl group having 1 to 10 carbon atoms is the phenyl group.

[0129] Also, R 5The group is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, hydrocarbon group, or hydride group having 1 to 10 carbon atoms. Examples of alkyl groups having 1 to 10 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. Examples of alkenyl groups having 1 to 10 carbon atoms include vinyl, allyl, and butenyl groups. An example of an aryl group having 1 to 10 carbon atoms is the phenyl group.

[0130] Note that in equation (2), multiple R 4 These are independent of each other and may be different from each other or the same. 5 The same applies to multiple Rs. 4 and R 5 Of these, at least two are hydride groups.

[0131] Also, R 6 R is a substituted or unsubstituted alkyl group, aryl group, or hydrocarbon group having 1 to 8 carbon atoms. Examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. An example of an aryl group having 1 to 8 carbon atoms is the phenyl group. Multiple R 6 These are independent of each other, and may be different from each other or the same.

[0132] Note that R in equation (2) 4 ,R 5 ,R 6 Examples of substituents include methyl groups and vinyl groups, and methyl groups are preferred from the viewpoint of preventing intramolecular crosslinking reactions.

[0133] Furthermore, m and n are the number of repeating units constituting the linear organohydrogenpolysiloxane (B1) represented by formula (2), where m is an integer from 2 to 150 and n is an integer from 2 to 150. Preferably, m is an integer from 2 to 100 and n is an integer from 2 to 100.

[0134] Furthermore, linear organohydrogenpolysiloxane (B1) may be used alone or in combination of two or more types.

[0135] The branched organohydrogenpolysiloxane (B2) has a branched structure, which allows it to form regions with high crosslink density, and it is a component that greatly contributes to the formation of a dense-sparse crosslink structure in the silicone rubber system. Also, similar to the linear organohydrogenpolysiloxane (B1) described above, it has a structure in which hydrogen is directly bonded to Si (≡Si-H), and it is a polymer that undergoes hydrosilylation reactions with the vinyl groups of vinyl group-containing organopolysiloxane (A) as well as the vinyl groups of components blended into the silicone rubber curable composition, thereby crosslinking these components.

[0136] Furthermore, the specific gravity of branched organohydrogenpolysiloxane (B2) is in the range of 0.9 to 0.95.

[0137] Furthermore, it is preferable that the branched organohydrogenpolysiloxane (B2) does not typically have vinyl groups. This effectively prevents the crosslinking reaction from proceeding within the branched organohydrogenpolysiloxane (B2) molecule.

[0138] Furthermore, the branched organohydrogenpolysiloxane (B2) is preferably the one shown in the following average composition formula (c).

[0139] Average composition formula (c) (H a (R 7 ) 3-a SiO 1 / 2 ) m (SiO 4 / 2 ) n (In equation (c), R 7 H is a monovalent organic group, a is an integer in the range of 1 to 3, and m is H a (R 7 ) 3-a SiO 1 / 2 The number of units, n is SiO 4 / 2 (The number of units)

[0140] In equation (c), R 7 The group is a monovalent organic group, preferably a substituted or unsubstituted alkyl group, aryl group, or hydrocarbon group having 1 to 10 carbon atoms. Examples of alkyl groups having 1 to 10 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. An example of an aryl group having 1 to 10 carbon atoms is the phenyl group.

[0141] In formula (c), a is the number of hydride groups (hydrogen atoms directly bonded to Si), and is an integer in the range of 1 to 3, preferably 1.

[0142] Also, in equation (c), m is H a (R 7 ) 3-a SiO 1 / 2 The number of units, n is SiO 4 / 2 It is the number of units.

[0143] Branched organohydrogenpolysiloxane (B2) has a branched structure. Linear organohydrogenpolysiloxane (B1) and branched organohydrogenpolysiloxane (B2) differ in their structure, with the number of alkyl groups R attached to Si (R / Si) being 1 when the number of Si is taken as 1. For linear organohydrogenpolysiloxane (B1), the range is 1.8 to 2.1, while for branched organohydrogenpolysiloxane (B2), it is 0.8 to 1.7.

[0144] Furthermore, because branched organohydrogenpolysiloxane (B2) has a branched structure, the amount of residue when heated to 1000°C at a heating rate of 10°C / min under a nitrogen atmosphere is 5% or more. In contrast, because linear organohydrogenpolysiloxane (B1) is linear, the amount of residue after heating under the above conditions is almost zero.

[0145] Furthermore, a specific example of a branched organohydrogenpolysiloxane (B2) is one having a structure represented by the following formula (3).

[0146] [ka]

[0147] In formula (3), R 7 R is a substituted or unsubstituted alkyl group, aryl group, or a hydrocarbon group combining these, or a hydrogen atom, having 1 to 8 carbon atoms. Examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. An example of an aryl group having 1 to 8 carbon atoms is the phenyl group. 7 Examples of substituents include methyl groups.

[0148] Note that in equation (3), multiple R 7 These are independent of each other, and may be different from each other or the same.

[0149] Furthermore, in equation (3), "-O-Si≡" indicates that Si has a branched structure that extends in three dimensions.

[0150] Furthermore, branched organohydrogenpolysiloxane (B2) may be used alone or in combination of two or more types.

[0151] Furthermore, the amount of hydrogen atoms (hydride groups) directly bonded to Si in the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) is not particularly limited. However, in the silicone rubber-based curable composition, it is preferable that the total amount of hydride groups in the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) is 0.5 to 5 moles, and more preferably 1 to 3.5 moles, per mole of vinyl groups in the vinyl group-containing linear organohydrogenpolysiloxane (A1). This ensures the reliable formation of a crosslinking network between the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) and the vinyl group-containing linear organohydrogenpolysiloxane (A1).

[0152] <<Silica particles (C)>> The silicone rubber-based curable composition of this embodiment may optionally contain silica particles (C) as a non-conductive filler.

[0153] The silica particles (C) are not particularly limited, but for example, fumed silica, calcined silica, precipitated silica, etc., can be used. These may be used individually or in combination of two or more types.

[0154] Silica particles (C) have a specific surface area of, for example, 50-400 m² as determined by the BET method. 2 It is preferable that the amount is / g, and 100-400m 2 It is more preferable that the amount is / g. Furthermore, the average primary particle size of the silica particles (C) is preferably, for example, 1 to 100 nm, and more preferably about 5 to 20 nm.

[0155] By using silica particles (C) within the specified range of specific surface area and average particle size, the hardness and mechanical strength of the resulting silicone rubber can be improved, particularly its tensile strength.

[0156] <<Silane coupling agent (D)>> The silicone rubber-based curable composition of this embodiment may contain a silane coupling agent (D). The silane coupling agent (D) may have a hydrolyzable group. The hydrolyzable group is hydrolyzed by water to a hydroxyl group, and this hydroxyl group undergoes a dehydration condensation reaction with the hydroxyl groups on the surface of the silica particles (C), thereby modifying the surface of the silica particles (C).

[0157] Furthermore, this silane coupling agent (D) may include a silane coupling agent having hydrophobic groups. As a result, these hydrophobic groups are imparted to the surface of the silica particles (C), which is expected to reduce the cohesive force of the silica particles (C) in the silicone rubber curable composition and, consequently, in the silicone rubber itself (reduced aggregation due to hydrogen bonding by silanol groups). This is expected to improve the dispersibility of the silica particles in the silicone rubber curable composition. This increases the interface between the silica particles and the rubber matrix, thereby increasing the reinforcing effect of the silica particles. Moreover, it is expected that the slipperiness of the silica particles within the matrix improves during deformation of the rubber matrix. As a result of the improved dispersibility and slipperiness of the silica particles (C), the mechanical strength of the silicone rubber due to the silica particles (C) (e.g., tensile strength and tear strength) is improved.

[0158] Furthermore, the silane coupling agent (D) may include a silane coupling agent having vinyl groups. This introduces vinyl groups to the surface of the silica particles (C). Therefore, during the curing of the silicone rubber-based curable composition, that is, when the vinyl groups of the vinyl group-containing organopolysiloxane (A) and the hydride groups of the organohydrogenpolysiloxane (B) undergo a hydrosilylation reaction to form a network (crosslinked structure), the vinyl groups of the silica particles (C) also participate in the hydrosilylation reaction with the hydride groups of the organohydrogenpolysiloxane (B), thus incorporating the silica particles (C) into the network. This makes it possible to achieve lower hardness and higher modulus in the formed silicone rubber.

[0159] As the silane coupling agent (D), a silane coupling agent having a hydrophobic group and a silane coupling agent having a vinyl group can be used in combination.

[0160] Examples of silane coupling agents (D) include those represented by the following formula (4).

[0161] Y n -Si-(X) 4-n ...(4) In formula (4) above, n represents an integer from 1 to 3. Y represents a functional group that has a hydrophobic group, a hydrophilic group, or a vinyl group, and when n is 1, it is a hydrophobic group, and when n is 2 or 3, at least one of them is a hydrophobic group. X represents a hydrolyzable group.

[0162] Hydrophobic groups are alkyl groups, aryl groups, or hydrocarbon groups having 1 to 6 carbon atoms, such as methyl groups, ethyl groups, propyl groups, and phenyl groups, with methyl groups being particularly preferred.

[0163] Furthermore, hydrophilic groups include, for example, hydroxyl groups, sulfonic acid groups, carboxyl groups, or carbonyl groups, with hydroxyl groups being particularly preferred. While hydrophilic groups may be included as functional groups, it is preferable that they are not included from the viewpoint of imparting hydrophobicity to the silane coupling agent (D).

[0164] Furthermore, hydrolyzable groups include alkoxy groups such as methoxy groups and ethoxy groups, chloro groups, or silazane groups, and among these, silazane groups are preferred due to their high reactivity with silica particles (C). Note that those having a silazane group as a hydrolyzable group are, due to their structural characteristics, (Y in formula (4) above. n It will have two -Si-) structures.

[0165] Specific examples of the silane coupling agent (D) represented by formula (4) above include, for example, alkoxysilanes such as methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, and decyltrimethoxysilane, which have a hydrophobic group as a functional group; chlorosilanes such as methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, and phenyltrichlorosilane; and hexamethyldisilazane, which have a hydrophobic group as a functional group. Examples of materials having a vinyl group include alkoxysilanes such as methacryloxypropyltriethoxysilane, methacryloxypropyltrimethoxysilane, methacryloxypropylmethyldiethoxysilane, methacryloxypropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and vinylmethyldimethoxysilane; chlorosilanes such as vinyltrichlorosilane and vinylmethyldichlorosilane; and divinyltetramethyldisilazane. Among these, considering the above description, hexamethyldisilazane is particularly preferred as the material having a hydrophobic group, and divinyltetramethyldisilazane is preferred as the material having a vinyl group.

[0166] In this embodiment, the lower limit of the silane coupling agent (D) content is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, based on 100 parts by weight of the total amount of vinyl group-containing organopolysiloxane (A). The upper limit of the silane coupling agent (D) content is preferably 100% by mass or less, more preferably 80% by mass or less, and even more preferably 40% by mass or less, based on 100 parts by weight of the total amount of vinyl group-containing organopolysiloxane (A). By setting the content of the silane coupling agent (D) above the lower limit, the overall mechanical strength of the silicone rubber can be improved when silica particles (C) are used. Furthermore, by setting the content of the silane coupling agent (D) below the upper limit, the silicone rubber can have appropriate mechanical properties.

[0167] <<Platinum or platinum compound (E)>> The silicone rubber-based curable composition of this embodiment may contain platinum or a platinum compound (E). Platinum or platinum compound (E) is a catalytic component that acts as a catalyst during hardening. The amount of platinum or platinum compound (E) added is the catalytic amount.

[0168] As platinum or a platinum compound (E), known substances can be used, such as platinum black, platinum supported on silica or carbon black, chloroplatinic acid or an alcoholic solution of chloroplatinic acid, a complex salt of chloroplatinic acid and an olefin, or a complex salt of chloroplatinic acid and a vinylsiloxane.

[0169] Platinum or platinum compound (E) may be used alone or in combination of two or more types.

[0170] <<Water(F)>> Furthermore, the silicone rubber-based curable composition of this embodiment may also contain water (F) in addition to the above components (A) to (E).

[0171] Water (F) functions as a dispersion medium that disperses the various components contained in the silicone rubber curable composition, and also contributes to the reaction between silica particles (C) and the silane coupling agent (D). Therefore, the silica particles (C) and the silane coupling agent (D) can be more reliably linked to each other in the silicone rubber, resulting in uniform properties overall.

[0172] Furthermore, if water (F) is included, its content can be set as appropriate, but specifically, it is preferably in the range of 10 to 100 parts by weight, and more preferably in the range of 30 to 70 parts by weight, per 100 parts by weight of the silane coupling agent (D). This allows the reaction between the silane coupling agent (D) and the silica particles (C) to proceed more reliably.

[0173] (Other ingredients) Furthermore, the silicone rubber-based curable composition of this embodiment may further contain other components in addition to the components (A) to (F) described above. Examples of these other components include inorganic fillers other than silica particles (C), such as diatomaceous earth, iron oxide, zinc oxide, titanium oxide, barium oxide, magnesium oxide, cerium oxide, calcium carbonate, magnesium carbonate, zinc carbonate, glass wool, and mica; additives such as reaction inhibitors, dispersants, pigments, dyes, antistatic agents, antioxidants, flame retardants, and thermal conductivity enhancers.

[0174] In a silicone rubber-based curable composition, the proportion of each component is not particularly limited, but for example, it can be set as follows.

[0175] In this embodiment, the upper limit of the silica particle (C) content may be, for example, 60 parts by weight or less, preferably 50 parts by weight or less, and more preferably 40 parts by weight or less, per 100 parts by weight of the total amount of vinyl group-containing organopolysiloxane (A). This allows for a balance of mechanical strengths such as hardness and tensile strength. The lower limit of the silica particle (C) content is not particularly limited, but may be, for example, 10 parts by weight or more, per 100 parts by weight of the total amount of vinyl group-containing organopolysiloxane (A).

[0176] The silane coupling agent (D) is preferably present in an amount of 5 to 100 parts by weight, and more preferably 5 to 40 parts by weight, per 100 parts by weight of the vinyl group-containing organopolysiloxane (A). This ensures that the dispersibility of silica particles (C) in the silicone rubber-based curable composition is reliably improved.

[0177] The content of organohydrogenpolysiloxane (B) is preferably, for example, 0.5 parts by weight to 20 parts by weight, and more preferably 0.8 parts by weight to 15 parts by weight, based on 100 parts by weight of the total amount of vinyl group-containing organopolysiloxane (A), silica particles (C), and silane coupling agent (D). A content of (B) within the above range may enable a more effective curing reaction.

[0178] The content of platinum or platinum compound (E) represents the catalytic amount and can be set as appropriate, but specifically, it is the amount such that the platinum group metal in this component is 0.01 to 1000 ppm by weight relative to the total amount of vinyl group-containing organopolysiloxane (A), silica particles (C), and silane coupling agent (D), preferably 0.1 to 500 ppm. By setting the content of platinum or platinum compound (E) to above the lower limit, the resulting silicone rubber composition can be sufficiently cured. By setting the content of platinum or platinum compound (E) to below the upper limit, the curing speed of the resulting silicone rubber composition can be improved.

[0179] Furthermore, if water (F) is included, its content can be set as appropriate, but specifically, it is preferably in the range of 10 to 100 parts by weight, and more preferably in the range of 30 to 70 parts by weight, per 100 parts by weight of the silane coupling agent (D). This allows the reaction between the silane coupling agent (D) and the silica particles (C) to proceed more reliably.

[0180] In this embodiment, the hardness, tensile strength, elongation at break, and tear strength can be controlled by appropriately selecting, for example, the type and amount of each component contained in the silicone rubber curable composition, the method of preparing the silicone rubber curable composition, etc. Among these, for example, appropriately controlling the type and blending ratio of the resin constituting the silicone rubber, the crosslinking density and crosslinking structure of the resin, improving the blending ratio of the inorganic filler and the bonding of the inorganic filler to the rubber, using a first vinyl group-containing linear organopolysiloxane (A1-1) with a vinyl group content of 0.4 mol% or less, using a silane coupling agent having vinyl groups, and appropriately adjusting the silica particle (C) content and the silane coupling agent content are examples of factors that can bring the hardness, tensile strength, elongation at break, and tear strength into desired numerical ranges.

[0181] <Method for manufacturing silicone rubber> Next, the method for manufacturing the silicone rubber of this embodiment will be described. The method for producing silicone rubber according to this embodiment involves preparing a silicone rubber-based curable composition and curing this silicone rubber-based curable composition to obtain silicone rubber. The details are explained below.

[0182] First, the components of the silicone rubber curable composition are uniformly mixed using any kneading device to prepare the silicone rubber curable composition.

[0183] [1] For example, a predetermined amount of vinyl group-containing organopolysiloxane (A), silica particles (C), and a silane coupling agent (D) are weighed out, and then kneaded using any kneading device to obtain a kneaded product containing these components (A), (C), and (D).

[0184] It is preferable to obtain this compound by first kneading a vinyl group-containing organopolysiloxane (A) and a silane coupling agent (D), and then kneading (mixing) silica particles (C). This further improves the dispersibility of silica particles (C) in the vinyl group-containing organopolysiloxane (A).

[0185] Furthermore, when obtaining this mixture, water (F) may be added to the mixture of components (A), (C), and (D) as needed. This allows the reaction between the silane coupling agent (D) and the silica particles (C) to proceed more reliably.

[0186] Furthermore, it is preferable that the kneading of each component (A), (C), and (D) proceeds through a first step of heating at a first temperature and a second step of heating at a second temperature. This allows the surface of the silica particles (C) to be surface-treated with the coupling agent (D) in the first step, and ensures that by-products generated by the reaction between the silica particles (C) and the coupling agent (D) are reliably removed from the kneaded mixture in the second step. Subsequently, if necessary, component (A) may be added to the resulting kneaded mixture and kneaded further. This improves the compatibility of the components in the kneaded mixture.

[0187] The first temperature is preferably, for example, around 40 to 120°C, and more preferably, around 60 to 90°C. The second temperature is preferably, for example, around 130 to 210°C, and more preferably, around 160 to 180°C.

[0188] Furthermore, the atmosphere in the first step is preferably an inert atmosphere such as a nitrogen atmosphere, and the atmosphere in the second step is preferably a reduced pressure atmosphere.

[0189] Furthermore, the duration of the first step is preferably about 0.3 to 1.5 hours, and more preferably about 0.5 to 1.2 hours. The duration of the second step is preferably about 0.7 to 3.0 hours, and more preferably about 1.0 to 2.0 hours.

[0190] By setting the conditions for the first and second steps as described above, the aforementioned effects can be obtained more significantly.

[0191] [2] Next, predetermined amounts of organohydrogenpolysiloxane (B) and platinum or a platinum compound (E) are weighed out, and then, using any kneading apparatus, components (B) and (E) are kneaded into the mixture prepared in step [1] above to obtain a silicone rubber curable composition. The obtained silicone rubber curable composition may be a paste containing a solvent.

[0192] Furthermore, when kneading each of these components (B) and (E), it is preferable to first knead the kneaded product prepared in step [1] with the organohydrogenpolysiloxane (B), and the kneaded product prepared in step [1] with platinum or a platinum compound (E), and then knead each of these kneaded products. This ensures that each of the components (A) to (E) can be reliably dispersed in the silicone rubber-based curable composition without allowing the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) to proceed.

[0193] The temperature at which components (B) and (E) are kneaded is preferably, as the roll setting temperature, around 10 to 70°C, and more preferably around 25 to 30°C.

[0194] Furthermore, the mixing time is preferably, for example, 5 minutes to 1 hour, and more preferably 10 to 40 minutes.

[0195] In steps [1] and [2] described above, by keeping the temperature within the above range, the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) can be more effectively prevented or suppressed. Furthermore, in steps [1] and [2] described above, by keeping the kneading time within the above range, each component (A) to (E) can be more reliably dispersed in the silicone rubber-based curable composition.

[0196] The kneading equipment used in each of the processes [1] and [2] is not particularly limited, but for example, a kneader, a two-roll mixer, a Banbury mixer (continuous kneader), a pressure kneader, etc., can be used.

[0197] Furthermore, in step [2], a reaction inhibitor such as 1-ethynylcyclohexanol may be added to the kneaded mixture. This makes it possible to more effectively prevent or suppress the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B), even if the temperature of the kneaded mixture is set to a relatively high temperature.

[0198] [3] Next, silicone rubber is formed by curing the silicone rubber-based curable composition.

[0199] In this embodiment, the curing process of the silicone rubber-based curable resin composition is carried out, for example, by heating at 100 to 250°C for 1 to 30 minutes (primary curing), followed by post-baking at 200°C for 1 to 4 hours (secondary curing).

[0200] By going through the above process, silicone rubber consisting of a cured product of a silicone rubber-based curable resin composition is obtained.

[0201] [3] Next, an insulating paste can be obtained by dissolving the silicone rubber-based curable composition obtained in step [2] in a solvent. Furthermore, [3] Next, a conductive paste can be obtained by dissolving the silicone rubber-based curable composition obtained in step [2] in a solvent and adding a conductive filler.

[0202] (solvent) Conductive pastes and insulating pastes contain solvents. Various known solvents can be used as the solvent, but for example, high-boiling point solvents may be included. These may be used individually or in combination of two or more.

[0203] The lower limit of the boiling point of the high-boiling-point solvent is, for example, 100°C or higher, preferably 130°C or higher, and more preferably 150°C or higher. This improves the printing stability, such as in screen printing. On the other hand, the upper limit of the boiling point of the high-boiling-point solvent is not particularly limited, but may be, for example, 300°C or lower, 290°C or lower, or 280°C or lower. This suppresses excessive thermal history during wiring formation, thereby preventing damage to the substrate and maintaining the shape of the wiring formed with conductive paste in good condition.

[0204] Furthermore, the solvent can be appropriately selected from the viewpoint of its solubility and boiling point for the silicone rubber-based curable resin composition, but for example, it may include aliphatic hydrocarbons having 5 to 20 carbon atoms, preferably aliphatic hydrocarbons having 8 to 18 carbon atoms, and more preferably aliphatic hydrocarbons having 10 to 15 carbon atoms.

[0205] Examples of solvents include aliphatic hydrocarbons such as pentane, hexane, cyclohexane, heptane, methylcyclohexane, ethylcyclohexane, octane, decane, dodecane, and tetradecane; aromatic hydrocarbons such as benzene, toluene, ethylbenzene, xylene, mesitylene, trifluoromethylbenzene, and benzotrifluoride; and diethyl ether, diisopropyl ether, dibutyl ether, cyclopentyl methyl ether, cyclopentyl ethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, and diethylene glycol dimethyl ether. Examples include ethers such as chol monobutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol methyl-n-propyl ether, 1,4-dioxane, 1,3-dioxane, and tetrahydrofuran; haloalkanes such as dichloromethane, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,1-trichloroethane, and 1,1,2-trichloroethane; carboxylic acid amides such as N,N-dimethylformamide and N,N-dimethylacetamide; sulfoxides such as dimethyl sulfoxide and diethyl sulfoxide; and esters such as diethyl carbonate. These may be used individually or in combination of two or more. The solvent used here should be appropriately selected from among solvents that can uniformly dissolve or disperse the components of the conductive paste described above.

[0206] The above solvent has a polarity term (δ) in the Hansen solubility parameter. p The upper limit of ) is, for example, 10 MPa 1 / 2 The following is preferred: 7 MPa 1 / 2 The following, and more preferably 5.5 MPa 1 / 2 The following first solvent may be included. This improves the dispersibility and solubility of the silicone rubber-based curable resin composition in the paste. The above polarity term (δ) of this first solvent p The lower limit of ) is not particularly limited, but for example, 0 Pa 1 / 2 That's fine too.

[0207] The hydrogen bonding term (δ) of the Hansen solubility parameter in the first solvent described above. h The upper limit of ) is, for example, 20 MPa 1 / 2 The following, preferably 10 MPa 1 / 2 The following is more preferable: 7 MPa 1 / 2 The following is the result. This makes it possible to improve the dispersibility and solubility of the silicone rubber-based curable resin composition in the paste. The above hydrogen bonding term (δ) of this first solvent h The lower limit of ) is not particularly limited, but for example, 0 Pa 1 / 2 That's fine too.

[0208] Hansen's solubility parameter (HSP) is an index that represents the solubility of one substance, indicating how much of it dissolves in another substance. HSP represents solubility as a three-dimensional vector. This three-dimensional vector typically includes a dispersion term (δ). d ), polarity term (δ p ), hydrogen bond term (δ h It can be represented as follows. And if the vectors are similar, it can be judged that they have high solubility. The similarity of the vectors can be judged by the distance of the Hansen solubility parameters (HSP distance).

[0209] The Hansen solubility parameters (HSP values) used in this specification can be calculated using software called HSPiP (Hansen Solubility Parameters in Practice). HSPiP, developed by Hansen and Abbott, includes a function to calculate HSP distances and a database containing Hansen parameters for various resins and solvents or non-solvents. The solubility of each resin in pure solvents and mixed solvents of good and poor solvents is investigated, and the results are entered into the HSPiP software to calculate D: dispersion term, P: polarity term, H: hydrogen bonding term, and R0: solubility sphere radius.

[0210] As the solvent in this embodiment, for example, one can be selected that has a small difference in HSP distance, polarity term, and hydrogen bonding term between the elastomer or the constituent units of the elastomer and the solvent.

[0211] The lower limit of viscosity of conductive paste and / or insulating paste measured at room temperature (25°C) with a shear rate of 20 [1 / s] is, for example, 1 Pa·s or more, preferably 5 Pa·s or more, and more preferably 10 Pa·s or more. This improves film formation and enhances shape retention even when forming thick films. On the other hand, the upper limit of viscosity of conductive paste and / or insulating paste at room temperature (25°C) is, for example, 100 Pa·s or less, preferably 90 Pa·s or less, and more preferably 80 Pa·s or less. This improves printability of the paste.

[0212] At room temperature of 25°C, the viscosity measured at a shear rate of 1 [1 / s] is defined as η1, and the viscosity measured at a shear rate of 5 [1 / s] is defined as η5. The thixotropy index is defined as the viscosity ratio (η1 / η5). In this case, the lower limit of the thixotropy of the conductive paste and / or insulating paste is, for example, 1.0 or higher, preferably 1.1 or higher, and more preferably 1.2 or higher. This allows the shape of the wiring obtained by the printing method to be stably maintained. On the other hand, the upper limit of the thixotropy of the conductive paste and / or insulating paste is, for example, 3.0 or lower, preferably 2.5 or lower, and more preferably 2.0 or lower. This improves the printability of the paste.

[0213] The content of the silicone rubber-based curable composition in the insulating paste is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, based on 100% by mass of the insulating paste. Furthermore, the content of the silicone rubber-based curable composition in the insulating paste is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less, based on 100% by mass of the insulating paste.

[0214] (Conductive filler) As the conductive filler, known conductive materials may be used, but metal powder (G) may also be used. The metals that make up the metal powder (G) are not particularly limited, but for example, it may include at least one of copper, silver, gold, nickel, tin, lead, zinc, bismuth, antimony, or alloys thereof, or two or more of these. Of these, the metal powder (G) is preferably silver or copper, that is, silver powder or copper powder, due to its high conductivity and ease of availability. Furthermore, these metal powders (G) can also be used if they are coated with other types of metal.

[0215] In this embodiment, there are no restrictions on the shape of the metal powder (G), but conventionally used shapes such as dendritic, spherical, or flake-shaped can be used. Among these, flake-shaped metal powder (G) may also be used.

[0216] Furthermore, the particle size of the metal powder (G) is not limited, but for example, the average particle size D 50 The particle size is preferably 0.001 μm or larger, more preferably 0.01 μm or larger, and even more preferably 0.1 μm or larger. The particle size of the metal powder (G) is, for example, the average particle size D 50 The particle size is preferably 1,000 μm or less, more preferably 100 μm or less, and even more preferably 20 μm or less. Average particle size D 50By setting the range to this extent, the silicone rubber can exhibit appropriate conductivity. The particle size of the metal powder (G) can be defined, for example, by observing conductive paste or silicone rubber molded using conductive paste with a transmission electron microscope, performing image analysis, and then determining the average value of 200 arbitrarily selected metal powders.

[0217] The content of conductive filler in the conductive paste is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more, based on the total content of the conductive paste. Furthermore, the content of conductive filler in the conductive paste is preferably 85% by mass or less, more preferably 75% by mass or less, and even more preferably 65% ​​by mass or less, based on the total content of the conductive paste. By setting the conductive filler content above the lower limit, the silicone rubber can acquire appropriate conductivity. Furthermore, by setting the conductive filler content below the upper limit, the silicone rubber can acquire appropriate flexibility.

[0218] The content of the silicone rubber-based curable composition in the conductive paste is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, based on 100% by mass of the conductive paste. Furthermore, the content of the silicone rubber-based curable composition in the conductive paste is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, based on 100% by mass of the conductive paste. By setting the content of the silicone rubber-based curable composition to be above the lower limit, the silicone rubber can have appropriate flexibility. Furthermore, by setting the content of the silicone rubber-based curable composition to be below the upper limit, the mechanical strength of the silicone rubber can be improved.

[0219] The lower limit of the silica particle (C) content in the conductive paste is, for example, 1% by mass or more, preferably 3% by mass or more, and more preferably 4% by mass or more, based on 100% by mass of the total amount of silica particles (C) and conductive filler. This improves the mechanical strength of the silicone rubber. On the other hand, the upper limit of the silica particle (C) content in the conductive paste is, for example, 20% by mass or less, preferably 15% by mass or less, and more preferably 10% by mass or less, based on 100% by mass of the total amount of silica particles (C) and conductive filler. This allows for a balance between the stretch-electrical properties and mechanical strength of the silicone rubber.

[0220] The lower limit of the conductive filler content in the conductive cured product obtained by curing the conductive paste constituting the conductive elastomer layer 20 is, for example, 50% by mass or more, preferably 60% by mass or more, and more preferably 70% by mass or more, out of 100% by mass of the conductive cured product. This enhances the stretchable electrical properties. On the other hand, the upper limit of the conductive filler content in the conductive cured product is, for example, 90% by mass or less, preferably 88% by mass or less, and more preferably 85% by mass or less, out of 100% by mass of the conductive elastomer layer 20. This suppresses a decrease in rubber properties such as stretchability.

[0221] The lower limit of the silica particle (C) content in the conductive cured product obtained by curing the conductive paste constituting the conductive elastomer layer 20 can be, for example, 1% by mass or more, preferably 3% by mass or more, and more preferably 4% by mass or more, based on 100% by mass of the total amount of silica particles (C) and conductive filler. This can improve the mechanical strength of the silicone rubber. On the other hand, the upper limit of the silica particle (C) content in the conductive cured product can be, for example, 20% by mass or less, preferably 15% by mass or less, and more preferably 10% by mass or less, based on 100% by mass of the total amount of silica particles (C) and conductive filler. This can balance the stretch-electrical properties and mechanical strength of the silicone rubber.

[0222] The above describes the embodiments of the present invention, which are examples of the present invention, and various configurations other than the above can be adopted. Further, the present invention is not limited to the above-described embodiments, and modifications, improvements, etc. within the scope capable of achieving the object of the present invention are included in the present invention. Examples of reference formats are provided below. 1. Flexible base material and An elastomer electrode layer containing conductive filler A and elastomer A is provided on the surface of the flexible substrate, The system includes an elastomer edge protection member that covers at least a portion of the edge of the elastomer electrode layer to at least a portion of the surface of the flexible substrate, A flexible sheet electrode in which the end protection member is configured to be more flexible than the elastomer electrode layer. 2. The flexible sheet electrode described in 1. A flexible sheet electrode wherein the end protection member is composed of a conductive elastomer containing conductive filler B and elastomer B in a quantity less than the content of conductive filler A contained in the elastomer electrode layer, or is composed of an insulating elastomer containing elastomer C but not conductive filler. 3. A flexible sheet electrode as described in 1. or 2., A flexible sheet electrode in which the elastomer electrode layer and the end protection member include silicone rubber. 4. A flexible sheet electrode as described in any one of 1. to 3., A flexible sheet electrode in which the end protection member covers the upper and side surfaces of the end of the elastomer electrode layer so as to be in contact with them. 5. A flexible sheet electrode as described in any one of 1. to 4., A flexible sheet electrode in which the interface between the elastomer electrode layer and the end protection member is seamlessly formed. 6. A flexible sheet electrode as described in any one of items 1 to 5, The conductive filler A is a flexible sheet electrode containing silver powder. 7. A flexible sheet electrode as described in any one of 1. to 6., A flexible sheet electrode wherein the content of the conductive filler A in the elastomer electrode layer is 50% by mass or more and 90% by mass or less. 8. A flexible sheet electrode as described in any one of 1. to 7., A flexible sheet electrode in which the elastomer electrode layer and / or the end protection member contains a non-conductive filler. 9. A flexible sheet electrode as described in any one of items 1 to 8, A flexible sheet electrode is configured such that, when the flexible sheet electrode is viewed perpendicular to its surface, S1 is the surface area of ​​the elastomer electrode layer, and S2 is the area of ​​the portion of the end protection member that covers the surface of the elastomer electrode layer, S1 and S2 satisfy 0.03 ≤ S2 / S1 ≤ 0.7. 10. A flexible sheet electrode as described in any one of items 1 to 9, A flexible sheet electrode, wherein when the flexible sheet electrode is viewed in cross-section in the lamination direction, the thickness of the elastomer electrode layer is H1 and the thickness of the end protection member is H2, and H1 and H2 are configured such that 0.3 ≤ H2 / H1 ≤ 0.8. 11. A flexible sheet electrode as described in any one of 1. to 10., A flexible sheet electrode is configured such that when M1 is the 100% modulus during a tensile test at the center of the elastomer electrode layer and M2 is the 100% modulus during a tensile test at the end protective member, M1 and M2 satisfy the condition 0.1 ≤ M2 / M1 ≤ 3.0. 12. A flexible sheet electrode as described in any one of 1. to 11., Washable, flexible sheet electrodes. 13. A wearable bioelectrode comprising a flexible sheet electrode as described in any one of 1. to 12. and an external connection part electrically connected to the flexible sheet electrode. 14. A biosensor comprising a wearable bioelectrode as described in 13. and an electronic component electrically connected to an external connection part in the wearable bioelectrode. 15. A step of forming a sheet-like film by applying a conductive paste for an elastomer electrode layer containing conductive filler A and elastomer A onto the surface of a flexible substrate, The process includes the step of applying an edge protection paste to cover at least a portion of the edge of the sheet-like film and at least a portion of the surface of the flexible substrate, and then heat-treating it to form an elastomer electrode layer and an edge protection member, The paste for the end protection member is a conductive paste B containing conductive filler B and elastomer B in a quantity less than the content of conductive filler A contained in the paste, or an insulating paste containing elastomer C but no conductive filler. A method for manufacturing flexible sheet electrodes.

Example

[0223] Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the description of these examples at all.

[0224] The raw material components shown in Table 1 are shown below. (A1-1): First vinyl group-containing linear organopolysiloxane: vinyl group-containing dimethylpolysiloxane synthesized by the following synthesis scheme 1 (structure represented by the above formula (1-1)) (A1-2): Second vinyl group-containing linear organopolysiloxane: vinyl group-containing dimethylpolysiloxane synthesized by the following synthesis scheme 2 (structure represented by the above formula (1-1), where R 1 and R 2 are vinyl groups)

[0225] (Organohydrogenpolysiloxane (B)) (B-1): Organohydrogenpolysiloxane: manufactured by Momentive, "TC-25D"

[0226] (Silica particles (C)) (C): Silica fine particles (particle size 7 nm, specific surface area 3 * 100 m 2 / g), manufactured by Nippon Aerosil Co., Ltd., "AEROSIL 300"

[0227] (Silane coupling agent (D)) (D-1): Hexamethyldisilazane (HMDZ), manufactured by Gelest, "HEXAMETHYLDISILAZANE (SIH6110.1)" (D-2) Divinyltetramethyldisilazane, manufactured by Gelest, "1,3-DIVINYLTETRAMETHYLDISILAZANE (SID4612.0)"

[0228] (Platinum or platinum compound (E)) (E-1): Platinum compound (manufactured by Momentive, trade name "TC-25A")

[0229] (Water(F)) (F):Pure water

[0230] (Metal powder (G)) (G1): Silver powder, manufactured by Tokuriki Chemical Research Institute, product name "TC-101", median diameter d 50 : 8.0 μm, aspect ratio 16.4, average major diameter 4.6 μm

[0231] (Synthesis of vinyl group-containing organopolysiloxane (A)) [Synthesis Scheme 1: Synthesis of the first vinyl group-containing linear organopolysiloxane (A1-1)] A first vinyl group-containing linear organopolysiloxane (A1-1) was synthesized according to the following formula (5). Specifically, 74.7 g (252 mmol) of octamethylcyclotetrasiloxane and 0.1 g of potassium silicate were placed in a 300 mL separable flask equipped with a condenser and stirring blades, which had been purged with Ar gas. The mixture was then heated and stirred at 120°C for 30 minutes. An increase in viscosity was observed during this process. The temperature was then raised to 155°C, and stirring was continued for 3 hours. After 3 hours, 0.1 g (0.6 mmol) of 1,3-divinyltetramethyldisiloxane was added, and stirring was continued at 155°C for another 4 hours. Furthermore, after 4 hours, the mixture was diluted with 250 mL of toluene and washed three times with water. The organic layer after washing was reprecipitated and purified by washing several times with 1.5 L of methanol to separate the oligomer and polymer. The obtained polymer was dried under reduced pressure at 60°C overnight to obtain the first vinyl group-containing linear organopolysiloxane (A1-1) (Mn = 2.2 × 10⁻⁶). 5 Mw = 4.8 × 10 5 Furthermore, the vinyl group content, calculated by 1H-NMR spectroscopy, was 0.04 mol%.

[0232] [ka]

[0233] [Synthesis Scheme 2: Synthesis of the second vinyl group-containing linear organopolysiloxane (A1-2)] In the synthesis step of (A1-1) described above, 0.86 g (2.5 mmol) of 2,4,6,8-tetramethyl2,4,6,8-tetravinylcyclotetrasiloxane was used in addition to 74.7 g (252 mmol) of octamethylcyclotetrasiloxane. Except for this difference, the synthesis step was carried out in the same manner as in (A1-1), and a second vinyl group-containing linear organopolysiloxane (A1-2) was synthesized as shown in formula (6) below (Mn = 2.3 × 10⁻¹⁵). 5 Mw = 5.0 × 10 5 Furthermore, the vinyl group content, calculated by 1H-NMR spectroscopy, was 0.93 mol%.

[0234] [ka]

[0235] (Preparation of silicone rubber-based curable compositions) The silicone rubber-based curable compositions for Samples 1-3 were prepared according to the following procedure. First, a mixture of 90% vinyl group-containing organopolysiloxane (A), silane coupling agent (D), and water (F) was pre-kneaded in the proportions shown in Table 1 below. Then, silica particles (C) were added to the mixture and kneaded further to obtain a compound (silicone rubber compound). Here, the mixing after the addition of silica particles (C) was carried out in two steps: the first step of mixing under a nitrogen atmosphere at 60-90°C for 1 hour for the coupling reaction, and the second step of mixing under a reduced pressure atmosphere at 160-180°C for 2 hours to remove the by-product (ammonia). After that, it was cooled, and the remaining 10% vinyl group-containing organopolysiloxane (A) was added in two parts and mixed for 20 minutes. Next, organohydrogenpolysiloxane (B), platinum, or a platinum compound (E) were added to 100 parts by weight of the resulting mixture (silicone rubber compound) in the proportions shown in Table 2 below, and the mixture was kneaded with a roll to obtain a silicone rubber-based curable composition.

[0236] (Preparation of conductive pastes 1-3 and insulating paste 1) The obtained 15.3 parts by weight of the silicone rubber-based curable composition of Sample 1 was immersed in 34.8 parts by weight of decane (solvent), then stirred with a rotating / revolving mixer, and after adding 65.2 parts by weight of metal powder (G1), the mixture was further kneaded with the rotating / revolving mixer to obtain conductive paste 1 (conductive paste for elastomer electrode layer) with a total content of 69.8% by weight of the silicone rubber-based curable composition and metal powder (G1).

[0237] The obtained 15.3 parts by weight of the silicone rubber-based curable composition of Sample 2 was immersed in 34.8 parts by weight of tetradecane (solvent), then stirred with a rotating / revolving mixer, and after adding 65.2 parts by weight of metal powder (G1), the mixture was further kneaded with the rotating / revolving mixer to obtain conductive paste 2 (conductive paste for elastomer electrode layer) with a total content of 69.8% by weight of the silicone rubber-based curable composition and metal powder (G1).

[0238] The obtained 15.3 parts by weight of the silicone rubber-based curable composition of Sample 1 was immersed in 34.8 parts by weight of decane (solvent), then stirred with a rotating / revolving mixer, and after adding 15.3 parts by weight of metal powder (G1), the mixture was further kneaded with the rotating / revolving mixer to obtain conductive paste 3 (conductive paste for end protection member) with a total content of 46.8% by weight of the silicone rubber-based curable composition and metal powder (G1).

[0239] The obtained 20 parts by weight of the silicone rubber-based curable composition of Sample 3 was immersed in 42.5 parts by weight of decane (solvent), and then stirred and kneaded in a rotating / revolving mixer to obtain insulating paste 1 (insulating paste for end protection member).

[0240] [Table 1]

[0241] (Fabrication of flexible sheet electrodes) A flexible base material (polyester knitted fabric, weight 130g / m²) measuring 7cm x 7cm x 0.4mmth thick is applied to the flat surface of a stainless steel substrate. 2A ) was placed, and then a mask (made of polyethylene terephthalate) with one 5cm x 5cm opening and a thickness of 125μm was placed on the surface of the flexible substrate. Next, the conductive paste for the elastomer electrode layer described above was applied to the opening of the mask, and squeegee printing was performed using a glass plate in a printing direction perpendicular to the grain of the fibers, based on the printing conditions shown in Table 2. Next, the mask was removed, and the printed conductive paste 1 was dried at 140°C for 20 minutes to form a sheet-like dried film. Squeegee printing was performed using the edge protection paste (insulating paste or conductive paste) shown in Table 2, via a mask, to cover the entire perimeter of the obtained sheet-like dried film when viewed from above. As shown in Figure 1(a), the edge protection paste was applied in such a way that it covered a portion of the surface and sides of the dried film, which would become the elastomer electrode layer, as well as a portion of the surface of the flexible substrate. Subsequently, the material was cured at 180°C for 2 hours to produce a flexible sheet electrode equipped with an elastomer electrode layer and edge protection members on a flexible substrate. Furthermore, the ratio of the area of ​​the portion of the end protection member covering the surface of the elastomer electrode layer to the surface area of ​​the elastomer electrode layer (S2 / S1) was 0.17, and the ratio of the thickness of the end protection member to the thickness of the elastomer electrode layer (H2 / H1) was 0.55. Furthermore, observation of one of the cross-sectional images of Examples 1 to 3 revealed that the elastomer electrode layer region and the edge protection member region could be roughly distinguished by the difference in the content of conductive filler (metal powder). However, no breaks (linear regions where silicone rubber is absent) were observed near the interface between the two, confirming that they were constructed seamlessly.

[0242] (Comparative Example 1) A flexible sheet electrode was fabricated in the same manner as in Example 1, comprising an elastomer electrode layer provided on a flexible substrate and without end protection members, except that end protection members were not formed.

[0243] [Table 2]

[0244] The following items were evaluated for the obtained flexible sheet electrodes. The results are shown in Table 2.

[0245] (100% modulus) Using the conductive pastes 1-3 and insulating paste 1 described above, each was dried at 140°C for 20 minutes and cured at 180°C for 2 hours to form a sheet of silicone rubber with a thickness of 0.05 mm. Using the obtained 0.05 mm thick sheet of silicone rubber, a dumbbell-shaped No. 6 test specimen was prepared in accordance with JIS K6251 (2004). The tensile stress (100% modulus) of the obtained dumbbell-shaped No. 6 test specimen at 100% elongation was measured at 25°C at a tensile speed of 500 mm / min. The unit is MPa. The values ​​obtained were taken as the 100% modulus for the elastomer electrode layer and end protection member of each example and comparative example.

[0246] (Surface resistivity) The printed portion of the obtained flexible sheet electrode was cut into 1cm x 1cm sections to prepare a sample. Using that sample, the surface resistivity (Ω / □) of the elastomer electrode layer was measured using the four-probe method with a probe applied to the center while the layer was still unextended. For surface resistivity measurements of the end protection members, a 1cm x 1cm sample was used, prepared by drying an end protection member paste (insulating paste or conductive paste) at 140°C for 20 minutes and curing it at 180°C for 2 hours. In Table 2, "Over Load" means that measurement was not possible due to the high resistance of the end protection member.

[0247] (Washing resistance test) The resulting flexible sheet electrodes were subjected to the following washing resistance test. 1. The flexible sheet electrode was stretched and contracted 300 times in both the vertical and horizontal directions to 100%. 2. Put neutral detergent and water into a beaker, immerse the flexible sheet electrode that has been treated in step 1, and stir for 24 hours. 3. Pour water into a beaker, immerse the flexible sheet electrode that has been treated in step 2, stir for 10 minutes, and rinse off the detergent. 4. Dry in an oven at 90°C for 30 minutes. The above steps 1-4 were repeated 50 times. In each example and comparative example, visual observation was performed to determine whether or not cracks occurred in the elastomer electrode layer after the washing resistance test described above.

[0248] (Bioelectric potential measurement) In each of the obtained examples of flexible sheet electrodes, an external connector (a metal male snap button) was attached to the other side of the flexible substrate opposite to the side on which the elastomer electrode layer was formed, and the external connector and the elastomer electrode layer were electrically connected to obtain a wearable bioelectrode. Three wearable bioelectrodes were prepared, and the external connection points of each of the three wearable bioelectrodes were connected to a BITalino (manufactured by Plux) via electrode cables with connectors (female snap buttons) and ECG sensors (manufactured by Plux), thereby creating an electrocardiogram measurement device (biosensor). Flexible sheet electrodes, each attached to one side of three wearable bioelectrodes, were placed directly on the subject's skin, and the subject's electrocardiogram was measured using a three-lead method (measurement point, reference, and body ground). The results above confirm that electrocardiogram waveforms can be monitored by using wearable bioelectrodes equipped with flexible sheet electrodes as described in each embodiment.

[0249] The flexible sheet electrodes of each embodiment showed suppressed crack formation after washing compared to Comparative Example 1. Such flexible sheet electrodes can be suitably used in wearable bioelectrodes. [Explanation of symbols]

[0250] 1. Flexible sheet electrode 2. Elastomer electrode layer 10 Flexible base material 11 one side 12 Main unit 13 Other side 14. Expansion section 20 Conductive elastomer layer 20a Conductive elastomer layer 20b Conductive elastomer layer 21 Impregnated layer 22 one side 23 layers 24 Stretchable wiring 26 Connection part 30 External connection section 32 Mounting plate 34 Mounting pins 50 protective layer 52 Insulating protective layer 60 Insulating elastomer layer 60a insulating elastomer layer 60b Insulating elastomer layer 70 End protection member 100 Wearable Bioelectrodes 200 biosensors 210 connector 220 Cable 230 Sensor Modules 240 Computers

Claims

1. Flexible substrate and An elastomer electrode layer containing conductive filler A and elastomer A is provided on the surface of the flexible substrate, The system includes an elastomer edge protection member that covers at least a portion of the edge of the elastomer electrode layer to at least a portion of the surface of the flexible substrate, The end protection member is configured to be more flexible than the elastomer electrode layer. The elastomer electrode layer and the end protection member include silicone rubber. Flexible sheet electrode.

2. A flexible base material, An elastomer electrode layer containing conductive filler A and elastomer A is provided on the surface of the flexible substrate, The system includes an elastomer edge protection member that covers at least a portion of the edge of the elastomer electrode layer to at least a portion of the surface of the flexible substrate, The end protection member is configured to be more flexible than the elastomer electrode layer. When the flexible sheet electrode is viewed in cross-section in the lamination direction, if the thickness of the elastomer electrode layer is H1 and the thickness of the end protection member is H2, then H1 and H2 are configured to satisfy 0.3 ≤ H2 / H1 ≤ 0.

8. Flexible sheet electrode.

3. A flexible sheet electrode according to claim 1 or 2, A flexible sheet electrode wherein the end protection member is composed of a conductive elastomer containing conductive filler B and elastomer B in a quantity less than the content of conductive filler A contained in the elastomer electrode layer, or is composed of an insulating elastomer containing elastomer C but not conductive filler.

4. A flexible sheet electrode according to any one of claims 1 to 3, A flexible sheet electrode in which the end protection member covers the upper and side surfaces of the end of the elastomer electrode layer so as to be in contact with them.

5. A flexible sheet electrode according to any one of claims 1 to 4, A flexible sheet electrode in which the interface between the elastomer electrode layer and the end protection member is seamlessly formed.

6. A flexible sheet electrode according to any one of claims 1 to 5, The conductive filler A is a flexible sheet electrode containing silver powder.

7. A flexible sheet electrode according to any one of claims 1 to 6, A flexible sheet electrode wherein the content of the conductive filler A in the elastomer electrode layer is 50% by mass or more and 90% by mass or less.

8. A flexible sheet electrode according to any one of claims 1 to 7, A flexible sheet electrode in which the elastomer electrode layer and / or the end protection member contains a non-conductive filler.

9. A flexible sheet electrode according to any one of claims 1 to 8, A flexible sheet electrode is configured such that, when the flexible sheet electrode is viewed perpendicular to its surface, S1 is the surface area of ​​the elastomer electrode layer, and S2 is the area of ​​the portion of the end protection member that covers the surface of the elastomer electrode layer, S1 and S2 satisfy 0.03 ≤ S2 / S1 ≤ 0.

7.

10. A flexible sheet electrode according to any one of claims 1 to 9, A flexible sheet electrode is configured such that when M1 is the 100% modulus during a tensile test at the central part of the elastomer electrode layer and M2 is the 100% modulus during a tensile test at the end protective member, M1 and M2 satisfy the condition 0.1 ≤ M2 / M1 ≤ 1.

0.

11. A flexible sheet electrode according to any one of claims 1 to 10, Washable, flexible sheet electrodes.

12. A wearable bioelectrode comprising a flexible sheet electrode according to any one of claims 1 to 11, and an external connection part electrically connected to the flexible sheet electrode.

13. A biosensor comprising a wearable bioelectrode as described in claim 12, and an electronic component electrically connected to an external connection portion in the wearable bioelectrode.

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