Wearable biological electrode, biological sensor, and biological signal measurement system

Abstract

To provide a wearable bioelectrode excellent in deformation durability.SOLUTION: The wearable bioelectrode of the present invention includes a flexible base material and a stretchable sheet electrode provided on the flexible base material and containing a conductive elastomer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wearable bioelectrode, a biosensor, and a biosignal measurement system. [Background technology]

[0002] Various developments have been made regarding wearable bioelectrodes. For example, the technology described in Patent Document 1 is known as an example of this type of technology. Patent Document 1 describes an electrocardiogram sensor having electrodes for detecting electrocardiogram signals, which are electrical signals generated by the heart, and a flexible sheet member, in which the electrodes are made of a conductive material such as metal (see, for example, Claim 1, paragraph 0022, and Figure 6A of Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-121700 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, as a result of investigations by the present inventors, it has been found that the wearable bioelectrode described in Patent Document 1 has room for improvement in terms of durability against deformation. [Means for solving the problem]

[0005] After further investigation, the inventor discovered that by constructing the sheet electrode from an elastic material, it is possible to realize a wearable bioelectrode that has excellent resistance to deformation when the flexible substrate is bent or stretched, thereby completing the present invention.

[0006] According to the present invention, A flexible substrate; a stretchable sheet electrode including a conductive elastomer provided on the flexible substrate; Equipped with A wearable bioelectrode is provided.

[0007] Furthermore, the present invention provides a biosensor including the above-described wearable bioelectrode.

[0008] Furthermore, according to the present invention, there is provided a biosignal measuring system including the above biosensor. [Effects of the Invention]

[0009] According to the present invention, a wearable bioelectrode having excellent resistance to deformation, a biosensor using the same, and a biosignal measuring system are provided. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a wearable bioelectrode according to an embodiment of the present invention. [Figure 2] 2 is a cross-sectional view taken along the line AA in FIG. 1. [Figure 3] 1 is a diagram illustrating an example of a configuration of a biosensor according to an embodiment of the present invention; [Figure 4] FIG. 10 is a diagram showing an example of the configuration of a modified example of the wearable bioelectrode of the present embodiment. [Figure 5] 1A to 1C are cross-sectional views illustrating an example of a manufacturing process for the wearable bioelectrode of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, similar components are designated by similar reference numerals, and descriptions thereof will be omitted where appropriate. Furthermore, the drawings are schematic diagrams and do not correspond to actual dimensional proportions.

[0012] The wearable bioelectrode of this embodiment will be outlined below.

[0013] The wearable bioelectrode of this embodiment comprises a flexible substrate and a stretchable sheet electrode including a conductive elastomer provided on the flexible substrate.

[0014] The wearable bioelectrode of this embodiment can detect potential fluctuations from a living body, such as heart rate, muscle activity, nervous system activity, etc. For example, the wearable bioelectrode may be configured to be used to measure at least one biopotential of cardiac potential, myogenic potential, and skin potential.

[0015] Wearable bioelectrodes can be further equipped with connectors and electronic components to form biosensors that can be connected to external devices. These biosensors are wearable. By analyzing biopotentials such as cardiac potentials detected by the biosensors, biosignal measurement systems suitable for a variety of applications can be constructed.

[0016] In the electrocardiogram sensor described in Patent Document 1, the electrodes are made of a non-stretchable material such as a metal material, and therefore may be broken by stretching or bending.

[0017] In contrast, in this embodiment, the sheet electrode provided on the flexible substrate is made of a stretchable material, making it possible to realize a stretchable and / or bendable wearable bioelectrode. Even when the substrate is deformed, such as by stretching or bending, breakage in the stretchable sheet electrode is suppressed, enabling stable measurement of biopotential. Furthermore, even when the substrate is deformed, peeling of the stretchable sheet electrode from the flexible substrate is suppressed, and adhesion between the electrodes is maintained. As described above, according to this embodiment, a wearable bioelectrode with excellent resistance to deformation can be realized.

[0018] According to this embodiment, the stretchable sheet electrode can be formed by a printing method using a conductive paste. That is, an example of the stretchable sheet electrode is composed of a printed layer of conductive paste. Therefore, it is possible to provide a wearable bioelectrode with excellent design freedom for the sheet electrode design.

[0019] Wearable bioelectrodes can be used as wearable devices that can be attached to either the body or clothing. Such wearable bioelectrodes are stretchable, allowing them to conform to the surface shape and movement of the body. In this case, the wearable bioelectrode may be attached directly to the body or via a body-attached member (clothing). Clothing with a wearable bioelectrode may 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, for example.

[0020] Furthermore, according to this embodiment, a washable wearable bioelectrode can be realized. Although the detailed mechanism is unclear, it is thought that this is because, even if the flexible substrate is deformed when washed in a home washing machine, the sheet electrode is made of an elastic material, which prevents the elastic sheet electrode from peeling off from the flexible substrate.

[0021] Such wearable bioelectrodes, biosensors using them, and biosignal measurement systems are expected to be used in a variety of situations, including physical diagnosis, health management, fitness, rehabilitation, and nursing care.

[0022] Each component of the wearable bioelectrode of this embodiment will be described in detail.

[0023] Fig. 1 is a top view showing an example of the configuration of a wearable bioelectrode 100. Fig. 2 is a cross-sectional view taken along line AA in Fig. 1.

[0024] The wearable bioelectrode 100 in FIG. 1 includes a flexible substrate 10 and a stretchable sheet electrode 20.

[0025] The wearable bioelectrode 100 has one surface 22 of the stretchable sheet electrode 20 that conforms to the body of the subject, and can detect bioelectric signals generated by biological activity of the heart, muscles, skin, nerves, etc. When the wearable bioelectrode 100 is provided with multiple stretchable sheet electrodes 20, it can be suitably used as an electrode for measuring an electrocardiogram.

[0026] Subjects include humans and non-human animals.

[0027] The wearable bioelectrode 100 is not a wet sensor that requires application of gel to the measurement area of ​​the subject, but can be used as a dry sensor that is easy to use and can be used repeatedly.

[0028] The flexible substrate 10 is not particularly limited as long as it is a substrate that is stretchable and / or bendable, but may be made of, for example, an elastomer substrate or a fiber substrate.

[0029] The stretchable sheet electrode 20 provided on the flexible substrate 10 may be configured to be formed on one surface 11 of the flexible substrate 10, and / or may be configured to have a portion formed inside the flexible substrate 10.

[0030] When viewed from above, the flexible substrate 10 has an electrode formation region where the stretchable sheet electrode 20 is formed. In this electrode formation region, the flexible substrate 10 and the stretchable sheet electrode 20 are in close contact with each other when the flexible substrate 10 is not stretched or stretched, thereby increasing the mechanical strength of the entire wearable bioelectrode 100.

[0031] The flexible substrate 10 may also have a non-electrode region around the electroforming region where the stretchable sheet electrode 20 is not formed. This non-electrode region can be fitted with an attachment such as sewing thread or a snap button for attaching to clothing, etc. Alternatively, when the wearable bioelectrode 100 is wrapped around the body, such as the wrist or ankle, the non-electrode region of the flexible substrate 10 may be overlapped in the thickness direction to secure it to the body.

[0032] 1, at least a portion of the flexible substrate 10, 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-mounted bioelectrode that can be wrapped around a part of the body, such as the wrist or ankle.

[0033] 1 may have a main body 12 and an extension 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 extension portion 14 is suppressed. Therefore, connection failures in the external connection portion 30 attached to the extension portion 14 can be suppressed.

[0034] The upper limit of the thickness of the flexible substrate 10 can be set depending on the application, and may be, for example, 10 mm or less, preferably 1 mm or less, but from the perspective of wearable device applications, it is more preferably 600 μm or less. By setting the thickness to 600 μm or less, a thin film sheet-like wearable bioelectrode can be realized. From the viewpoint of mechanical strength, the lower limit of the thickness of the flexible substrate 10 is, for example, 10 μm or more, preferably 50 μm or more, and more preferably 100 μm or more.

[0035] An example of an elastomeric substrate for flexible substrate 10 is comprised of a stretchable insulating layer containing an insulating elastomer.

[0036] The upper limit of the durometer hardness A of the insulating elastomer is not particularly limited, but may be, for example, not more than 80, and preferably not more than 70. This improves the ease of deformation, which makes deformation such as bending and stretching easier. On the other hand, the lower limit of the durometer hardness A is, for example, 20 or more, preferably 30 or more, and more preferably 40 or more. This can improve the friction durability and mechanical strength of the insulating elastomer. Also, the washing resistance of the wearable bioelectrode 100 can be improved.

[0037] The lower limit of the tensile strength of the insulating elastomer is, for example, 5.0 MPa or more, preferably 6.0 MPa or more, and more preferably 7.0 MPa or more, thereby realizing a structure with excellent elongation durability during repeated elongation deformation. On the other hand, the upper limit of the tensile strength is not particularly limited, but may be, for example, 25 MPa or less, which allows the various properties of the insulating elastomer to be balanced.

[0038] The lower limit of the elongation at break of the insulating elastomer is, for example, 500% or more, preferably 600% or more, and more preferably 700% or more, which can improve the elongation durability during repeated elongation deformation. On the other hand, the upper limit of the breaking elongation is not particularly limited, but may be, for example, 2000% or less, or 1800% or less, which allows the various properties of the insulating elastomer to be balanced.

[0039] The lower limit of the tear strength of the insulating elastomer is, for example, 25 N / mm or more, preferably 28 N / mm or more, more preferably 30 N / mm or more, even more preferably 33 N / mm or more, and even more preferably 34 N / mm or more. This makes it possible to sew the flexible substrate 10 to clothing. That is, a sewable wearable bioelectrode 100 can be realized. Furthermore, the durability, scratch resistance, and mechanical strength of the silicone rubber can be improved during repeated use. On the other hand, the upper limit of the tear strength is not particularly limited, but may be, for example, 80 N / mm or less, or 70 N / mm or less, which allows the various properties of the insulating elastomer to be balanced.

[0040] In this embodiment, the following method can be used to measure the properties of each component of the wearable bioelectrode 100 and the properties of the elastomer used in each component. To measure the properties of each component, each component, such as a substrate, can be used as a test piece.

[0041] (Tear strength measurement conditions) A crescent-shaped test piece is prepared using the elastomer, and the tear strength of the obtained crescent-shaped test piece is measured at 25°C in accordance with JIS K6252 (2001).

[0042] (Tensile strength measurement conditions) A dumbbell-shaped No. 3 test piece is prepared using the elastomer, and the tensile strength of the obtained dumbbell-shaped No. 3 test piece is measured at 25°C in accordance with JIS K6251 (2004).

[0043] (Measurement conditions for breaking elongation) A dumbbell-shaped No. 3 test piece is prepared using the elastomer, and the resulting dumbbell-shaped No. 3 test piece is measured for breaking elongation at 25°C in accordance with JIS K6251 (2004).

[0044] (Durometer hardness A measurement procedure) A sheet-like test piece is prepared using the elastomer, and the durometer hardness A of the obtained sheet-like test piece at 25°C is measured in accordance with JIS K6253 (1997).

[0045] The stretchable sheet electrode 20 is composed of a stretchable conductive layer containing a conductive elastomer.

[0046] The stretchable sheet electrode 20 is configured in a sheet shape and has an exposed surface that comes into direct contact with the body. In this specification, the sheet-like shape refers to the thickness of the stretchable sheet electrode 20 being D (mm), and the area of ​​one surface 22 of the stretchable sheet electrode 20 in a top view being S (mm 2 ), S and D are, for example, 50≦S / D, preferably 200≦S / D, and more preferably 400≦S / D. The upper limit of S / D may be set depending on the measurement site of the subject, and is not particularly limited, but is, for example, S / D≦10 7 That's fine too.

[0047] The stretchable sheet electrode 20 comes into contact with the body when the wearable bioelectrode 100 is in use, and can conform well to the contact surface in accordance with the surface shape and deformation of the body.

[0048] In this specification, stretchability is expressed as the rate of stretching when stretched in a predetermined direction. The predetermined direction may be, for example, the direction in which the stretchable sheet electrode 20, specifically the stretchable sheet electrode 20, is at its maximum length in the top view of FIG. 1. If the shape of the stretchable sheet electrode 20 in top view is rectangular, it may be stretched in the diagonal direction. When stretched in this extension direction, having stretchability means that the stretchable sheet electrode 20 can be stretched to an elongation rate of, for example, 10% or more, preferably 20% or more, and more preferably 50% or more, and that the stretchable sheet electrode 20 does not break at that elongation rate.

[0049] The stretchable sheet electrode 20 in FIG. 1 is formed by laminating it on one surface 11 of a flexible substrate 10 containing an insulating elastomer.

[0050] In the wearable bioelectrode 100, the state in which the flexible substrate 10 and the stretchable sheet electrode 20 are stacked means that the surfaces of the stretchable insulating layer and the stretchable conductive layer that constitute them are in surface contact with each other, and may be chemically and / or physically bonded to each other and adhered to each other. This reduces the risk of damage, such as peeling of the stretchable sheet electrode 20 from the surface of the flexible substrate 10, even during stretching or repeated stretching. This makes it possible to realize a wearable bioelectrode 100 that is highly durable against deformation.

[0051] The stretchable sheet electrode 20 may be configured to be connected to the outside by itself, or may have a connecting portion 26 as a separate member. The stretchable sheet electrode 20 and the connecting portion 26 may be configured to be electrically connected via a stretchable wiring 24.

[0052] 1, the stretchable sheet electrode 20 is formed on one surface 11 of the main body 12 of the flexible substrate 10, and the connection portion 26 is formed on one surface 11 of the extension portion 14. The stretchable wiring 24 is formed from the main body 12 to the extension portion 14.

[0053] The stretchable sheet electrode 20, the stretchable wiring 24, and the connection part 26 are made of the same or different conductive elastomers, and are preferably made of the same conductive elastomer.

[0054] Each part constituting the stretchable sheet electrode 20 may be formed of a printed layer formed by a printing method using a conductive paste. In this case, each part including the stretchable sheet electrode 20, the stretchable wiring 24, and the connection part 26 may be formed seamlessly with one another.

[0055] The lower limit of the volume resistivity of the stretchable sheet electrode 20 at 25°C when unstretched is, for example, 1.0 × 10 -5 Ω·cm or more, preferably 2.0×10 -5 Ω·cm or more, preferably 5.0×10 -5 Ω·cm or more. On the other hand, the upper limit of the volume resistivity of the stretchable sheet electrode 20 at 25° C. when unstretched is, for example, 1.0×10 2 Ω·cm or less, preferably 1.0×10 -1 Ω·cm or less, preferably 1.0×10 -2 Ω·cm or less. By setting the thickness within this range, the conductive properties and deformation durability of the stretchable sheet electrode 20 can be balanced.

[0056] The lower limit of the surface resistivity of the stretchable sheet electrode 20 at 25°C when unstretched is, for example, 1.0 × 10 -4 Ω / □ or more, preferably 1.0×0 -3 Ω / □ or more, preferably 3.0×10 -3 It is Ω / □ or more. On the other hand, the upper limit of the surface resistivity of the stretchable sheet electrode 20 at 25°C when unstretched is, for example, 9.0 × 10 5 Ω / □ or less, preferably 1.0×10 4 Ω / □ or less, more preferably 1.0×10 3 It is Ω / □ or less. By setting the thickness within this range, the conductive properties and deformation durability of the stretchable sheet electrode 20 can be balanced.

[0057] When the resistance value of the stretchable sheet electrode 20 at 25°C when unstretched is R1 and the resistance value of the stretchable sheet electrode 20 at 25°C when stretched 50% is R2, R1 and R2 are configured to satisfy 1.5≦R2 / R1≦20. The lower limit of R2 / R1 is, for example, 1.5 or more, preferably 2.0 or more, and more preferably 2.5 or more. On the other hand, the upper limit of R2 / R1 is, for example, 20 or less, preferably 10 or less, and more preferably 8 or less. By keeping the ratio within this range, it is possible to achieve a balance between the conductive properties and the deformation durability. The lower limit of R2 is, for example, 0.5Ω or more, preferably 1Ω or more, and more preferably 1.5Ω or more, while the upper limit of R2 is, for example, 30Ω or less, preferably 20Ω or less, and more preferably 10Ω or less.

[0058] The volume resistivity, surface resistivity, and resistance value of the stretchable sheet electrode 20 can be measured at the portion that comes into contact with the body, specifically, at the stretchable sheet electrode 20. If the shape of the stretchable sheet electrode 20 in top view is rectangular, these measurements may be performed on the diagonal corners of the stretchable sheet electrode 20.

[0059] The external connection section 30 can send the bioelectrical signal detected through the stretchable sheet electrode 20 to an external device such as an electronic component.

[0060] The wearable bioelectrode 100 of FIG. The external connection part 30 is provided on the flexible substrate 10 on the side opposite to the stretchable sheet electrode 20. For example, the external connection part 30 in Fig. 2 is formed on the other surface 13 of the flexible substrate 10. This prevents the external connection part 30 from coming into contact with the body together with the stretchable sheet electrode 20 when the wearable bioelectrode 100 is in use, thereby preventing interference with the detection of bioelectric signals.

[0061] The external connection portion 30 is not particularly limited as long as it is configured to be electrically connected to the stretchable sheet electrode 20, but is made of a conductive material such as a metal material or a conductive elastomer.

[0062] The shape of the external connection portion 30 is not particularly limited, but it may have a connector that can be connected to an electronic component, or a structure that allows easy attachment of wiring.

[0063] An example of the external connection portion 30 may be a metal snap button. 2 is a male snap button, and is fixed to the flexible substrate 10 using a metal mounting plate 32 and a mounting pin 34. The fixing method of sandwiching the flexible substrate 10 between the external connection part 30 and the mounting plate 32 can prevent the external connection part 30 from shifting from its fixed position. The mounting pin 34 comes into contact with a part of the stretchable sheet electrode 20 , for example, the connection part 26 , and can establish electrical continuity between the stretchable sheet electrode 20 and the external connection part 30 .

[0064] 2 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 any insulating material, and may be made of an insulating elastomer such as silicone rubber, for example.

[0065] The biosensor of this embodiment will be described.

[0066] In one cross section of the wearable bioelectrode 100 in FIG. 2, the thickness of the flexible substrate 10 is designated as X, and the thickness of the stretchable sheet electrode 20 is designated as Y. X and Y are configured to satisfy, for example, 0.15≦Y / X≦1.1. The lower limit of Y / X is, for example, 0.15 or more, preferably 0.30 or more, and more preferably 0.40 or more, which can improve the washing durability. On the other hand, the upper limit of Y / X is, for example, 1.1 or less, preferably 1.05 or less, and more preferably 1.0 or less. This makes it possible to prevent the flexibility of the wearable bioelectrode 100 from decreasing.

[0067] Depending on the application, the biosensor may include one wearable bioelectrode 100 or two or more wearable bioelectrodes 100. The biosensor may be placed directly on the body, or may be placed on a body-attached member such as clothing.

[0068] The biosensor includes electronic components that can be electrically connected to the wearable bioelectrode 100 via the external connection unit 30.

[0069] Known electronic components can be used depending on the application, including, for example, an amplifier, an AD converter, a CPU, a memory, a communication circuit, a wireless communication unit, an analog filter, a capacitor, a resistor, and a battery. One or more of these components may be modularized on a circuit board. This allows the biosensor to be used as a wearable device. Further, other sensors such as an acceleration sensor, a temperature sensor, and a pressure sensor may also be used as electronic components.

[0070] FIG. 3 is a diagram illustrating an example of the configuration of the biosensor 200. As shown in FIG. The biosensor 200 in FIG. 3 includes the wearable bioelectrode 100, a connector 210, a cable 220, a sensor module 230, and a computer 240.

[0071] The connector 210 has a structure that can be electrically connected to the external connection part 30 of the wearable bioelectrode 100, and may have, for example, a female snap button. The cable 220 electrically connects the connector 210 to the sensor module 230 and the computer 240, which are electronic components. For electrocardiogram measurements, an ECG sensor module can be used as the sensor module 230. The sensor module 230 has electrical circuitry that suppresses interference from external RF sources, line frequencies, and electrical noise, thereby suppressing noise when measuring bioelectrical signals. The computer 240 can acquire bioelectric signals and generate and output biopotential waveforms such as surface electromyograms, electrocardiograms, skin potentials, and electroencephalograms. The computer 240 may be a single-board computer configured with a printed circuit board equipped with a CPU, peripheral components, input / output interfaces, connectors, etc.

[0072] The biological signal measuring system of this embodiment will be described. The biological signal measuring system of this embodiment includes a biological sensor, and may be a system (measuring device) that displays, analyzes, or stores data received from the biological sensor.

[0073] A modification of the wearable bioelectrode 100 will now be described.

[0074] 1, the wearable bioelectrode 100 may include a protective layer 50 between the flexible substrate 10 and the external connection part 30. This increases the mechanical strength and prevents the stretchable sheet electrode 20 from being damaged when an external terminal is connected to the external connection part 30, for example.

[0075] When viewed from the other surface 13, the protective layer 50 may be formed to be wider than the external connection portion 30, and may be formed to follow the shape of the extension portion 14 of the flexible substrate 10. This increases the mechanical strength of the extension portion 14.

[0076] The protective layer 50 may be made of any elastic material, such as an insulating elastomer such as silicone rubber, or the same material as the flexible substrate 10. This improves the adhesion between the flexible substrate 10 and the protective layer 50.

[0077] The flexible substrate 10 may be configured as a single layer or as a laminate of multiple layers. The wearable bioelectrode 100 may have a multilayer wiring structure in which flexible substrates 10 and stretchable sheet electrodes 20 are alternately stacked.

[0078] The shape of the flexible substrate 10 in top view is not particularly limited, and can be modified appropriately depending on the application.

[0079] The flexible substrate 10 may have one stretchable sheet electrode 20 on the same surface 11, but may also have two or more independent stretchable sheet electrodes 20.

[0080] The wearable bioelectrode 100a in FIG. 4 includes three stretchable sheet electrodes 20a, 20b, and 20c on a flexible substrate 10a. This wearable bioelectrode 100a can be used when measuring an electrocardiogram using a three-point lead method. Such a bioelectrode can prevent misalignment between sheet electrodes. Furthermore, the wearable bioelectrode 100a has a structure suitable for a clothing-mounted bioelectrode.

[0081] The shape of the stretchable sheet electrode 20 or the shape of the stretchable sheet electrode 20 as viewed from above is not particularly limited and can be modified as appropriate depending on the application, but examples include a square, a circle, an ellipse, other polygonal shapes, etc. This ensures a certain degree of contact area with the body and improves measurement stability.

[0082] The stretchable sheet electrode 20 or the corners of the stretchable sheet electrode 20 when viewed from above may be rounded, thereby preventing local stress from occurring at the corners during use and preventing the stretchable sheet electrode 20 from being damaged.

[0083] At least a portion of the stretchable sheet electrode 20, for example, the stretchable sheet electrode 20 may be configured in a sheet shape. At least a portion of the stretchable sheet electrode 20 may be embedded inside the flexible substrate 10.

[0084] The stretchable sheet electrode 20 may be composed of only the stretchable sheet electrode 20, without including the stretchable sheet electrode 20 and the connection portion 26. In this case, an external connection portion 30 is provided so as to be electrically connected to the stretchable sheet electrode 20.

[0085] The external connection part 30 may be made up of one member, or may be made up of an assembly of multiple members. The external connection portion 30 is attached to the flexible substrate 10 by a mechanical method, but may also be attached by a chemical method using an adhesive or the like.

[0086] The snap button used for the external connection part 30 may be either a male snap button or a female snap button. The external connection part 30 is fixed to the flexible substrate 10, but may also be attached in a detachable manner.

[0087] Next, the materials of the flexible substrate 10 and the stretchable sheet electrode 20 will be described.

[0088] In one example of the wearable bioelectrode 100 of this embodiment, the flexible substrate 10 is made of an insulating elastomer, and the stretchable sheet electrode 20 is made of a conductive elastomer. The insulating elastomer and the conductive elastomer may be configured to include the same elastomer material.

[0089] Examples of insulating elastomers that can be used include silicone rubber, urethane rubber, fluororubber, nitrile rubber, acrylic rubber, styrene rubber, chloroprene rubber, ethylene propylene rubber, etc. Among these, the elastomer includes one or more thermosetting elastomers (elastomer materials) selected from the group consisting of silicone rubber, urethane rubber, and fluororubber. The insulating elastomer may be composed of an elastomer material alone, or may be composed of an elastomer material and a non-conductive filler. An example of the insulating elastomer includes silicone rubber, preferably containing silicone rubber and a non-conductive filler. Silicone rubber is chemically stable among elastomers and also has excellent mechanical strength. Among these, from the viewpoint of hygiene, it is preferable to use silicone rubber as the elastomer material, which has high biocompatibility.

[0090] The conductive elastomer may be, for example, silicone rubber, urethane rubber, fluororubber, nitrile rubber, acrylic rubber, styrene rubber, chloroprene rubber, ethylene propylene rubber, etc. 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 the conductive elastomer contains silicone rubber and a conductive filler, which can enhance the elasticity and conductivity of the conductive elastomer.

[0091] At least one of the insulating elastomer and the conductive elastomer, preferably both, may contain a non-conductive filler. Known materials can be used as the non-conductive filler, such as silica particles, silicone rubber particles, and talc. Among these, silica particles may be used.

[0092] The conductive filler may include, for example, one or more selected from the group consisting of powdery or fibrous metal-based fillers, carbon-based fillers, metal oxide fillers, and metal-plated fillers. Among these, metal-based fillers such as silver powder may be used as the conductive filler.

[0093] The conductive elastomer may further contain a non-conductive filler in addition to the conductive filler, thereby improving the mechanical properties of the conductive elastomer.

[0094] As a specific example, the stretchable sheet electrode 20 may contain silver powder, preferably flaky silver powder, as a conductive filler, which can improve the electrical conductivity and, further, the stretchable conductivity. The stretchable sheet electrode 20 may also contain silver powder and silica particles as a non-conductive filler, thereby improving the stretch durability of the stretchable sheet electrode 20.

[0095] At least two or all of the conductive elastomer of the stretchable sheet electrode 20, the insulating elastomer of the flexible substrate 10, and the insulating elastomer of the protective layer 50 or the insulating protective layer 52 may be configured to contain the same elastomer material.

[0096] In this specification, "containing the same elastomer material" means that at least one or more of the same type of elastomer material is contained among the types of thermosetting elastomers exemplified above. Furthermore, when the same silicone rubber is contained, this silicone rubber may be constituted by a cured product of a silicone rubber-based curable composition containing a vinyl group-containing organopolysiloxane.

[0097] The insulating elastomer may be composed of a cured product of a silicone rubber-based curable composition containing a vinyl group-containing organopolysiloxane, and 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.

[0098] The components of the silicone rubber-based hardening composition will be described in detail below.

[0099] 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 non-conductive filler, the same type of silane coupling agent, and the same type of catalyst.

[0100] The same type of vinyl group-containing linear organopolysiloxanes are sufficient as long as they contain the same vinyl groups as functional groups and have a linear structure, but may differ in the amount of vinyl groups in the molecule, the molecular weight distribution, or the amount of vinyl groups added.

[0101] The same type of crosslinking agent may have at least a common structure such as a linear structure or a branched structure, and may have different molecular weight distributions in the molecule, different functional groups, or different amounts of functional groups added.

[0102] Non-conductive fillers of the same type may have at least a common constituent material, but may differ in particle size, specific surface area, surface treatment agent, or amount of the surface treatment agent added.

[0103] Silane coupling agents of the same type are only required to have at least a common functional group, and may differ in other functional groups in the molecule or in the amount added.

[0104] The same type of catalysts are those that have at least common constituent materials, and may contain different compositions or may have different amounts of the components added.

[0105] The silicone rubber-based curable composition constituting the same silicone rubber may further contain one or more different types of vinyl group-containing linear organopolysiloxanes, crosslinking agents, non-conductive fillers, silane coupling agents, and catalysts.

[0106] 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 serves as the main component of the silicone rubber-based curable composition of this embodiment.

[0107] The vinyl group-containing organopolysiloxane (A) can contain a vinyl group-containing linear organopolysiloxane (A1) having a linear structure.

[0108] The vinyl group-containing linear organopolysiloxane (A1) has a linear structure and contains vinyl groups, which become crosslinking points during curing.

[0109] The vinyl group content of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but preferably has two or more vinyl groups in the molecule and is 15 mol% or less, which optimizes the amount of vinyl groups in the vinyl group-containing linear organopolysiloxane (A1) and ensures the formation of networks with the components described below.

[0110] In this specification, unless otherwise specified, the symbol "to" indicates that the upper and lower limits are included.

[0111] In this specification, the vinyl group content refers to the mole percent of vinyl group-containing siloxane units when all units constituting the vinyl group-containing linear organopolysiloxane (A1) are taken as 100 mole percent, where it is considered that there is one vinyl group per vinyl group-containing siloxane unit.

[0112] The degree of polymerization of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but is preferably within a range of, for example, about 1,000 to 10,000, and more preferably about 2,000 to 5,000. The degree of polymerization can be determined, for example, as the polystyrene-equivalent number-average degree of polymerization (or number-average molecular weight) measured by GPC (gel permeation chromatography) using chloroform as a developing solvent.

[0113] 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.

[0114] By using a vinyl group-containing linear organopolysiloxane (A1) having a degree of polymerization and specific gravity within the above ranges, it is possible to improve the heat resistance, flame retardancy, chemical stability, etc. of the resulting silicone rubber.

[0115] As the vinyl group-containing linear organopolysiloxane (A1), those having a structure represented by the following formula (1) are particularly preferred.

[0116] [ka]

[0117] In formula (1), R 1 is a hydrocarbon group selected from substituted or unsubstituted alkyl groups, alkenyl groups, aryl groups, or combinations thereof having 1 to 10 carbon atoms. Examples of alkyl groups having 1 to 10 carbon atoms include methyl groups, ethyl groups, and propyl groups, with methyl groups being preferred. Examples of alkenyl groups having 1 to 10 carbon atoms include vinyl groups, allyl groups, and butenyl groups, with vinyl groups being preferred. Examples of aryl groups having 1 to 10 carbon atoms include phenyl groups.

[0118] Also, R 2 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, or a hydrocarbon group combining these groups, each 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. Examples of aryl groups having 1 to 10 carbon atoms include phenyl groups.

[0119] Also, R 3 is a substituted or unsubstituted alkyl group or aryl group having 1 to 8 carbon atoms, or a hydrocarbon group consisting of a combination thereof. Examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. Examples of aryl groups having 1 to 8 carbon atoms include phenyl groups.

[0120] Furthermore, R in formula (1) 1 and R 2 Examples of the substituent of R include a methyl group and a vinyl group. 3 Examples of the substituent include a methyl group.

[0121] In addition, in formula (1), multiple R 1are independent of each other and may be different or the same. 2 , and R 3 The same is true for .

[0122] Furthermore, m and n are the numbers of repeating units constituting the vinyl group-containing linear organopolysiloxane (A1) represented by formula (1), where m is an integer of 0 to 2000 and n is an integer of 1000 to 10000. m is preferably 0 to 1000, and n is preferably 2000 to 5000.

[0123] Specific examples of the vinyl group-containing linear organopolysiloxane (A1) represented by formula (1) include those represented by the following formula (1-1).

[0124] [ka]

[0125] In formula (1-1), R 1 and R 2 are each independently a methyl group or a vinyl group, and at least one of them is a vinyl group.

[0126] The vinyl group-containing linear organopolysiloxane (A1) may contain a first vinyl group-containing linear organopolysiloxane (A1-1) having two or more vinyl groups in the molecule and having a vinyl group content of 0.4 mol% or less. The vinyl group content of the first vinyl group-containing linear organopolysiloxane (A1-1) may be 0.1 mol% or less.

[0127] The vinyl group-containing linear organopolysiloxane (A1) may also 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 %.

[0128] By combining a first vinyl-containing linear organopolysiloxane (A1-1) with a second vinyl-containing linear organopolysiloxane (A1-2) having a high vinyl group content as the raw rubber used to make the silicone rubber, the vinyl groups can be unevenly distributed, allowing for more effective formation of a crosslink density distribution within the crosslinked network of the silicone rubber, thereby more effectively increasing the tear strength of the silicone rubber.

[0129] Specifically, as the vinyl group-containing linear organopolysiloxane (A1), it is preferable to use, for example, a first vinyl group-containing linear organopolysiloxane (A1-1) having two or more units in which R1 is a vinyl group and / or units in which R2 is a vinyl group in the molecule, 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 in which R1 is a vinyl group and / or units in which R2 is a vinyl group, in the above formula (1-1).

[0130] The first vinyl group-containing linear organopolysiloxane (A1-1) preferably has a vinyl group content of 0.01 to 0.2 mol %, and the second vinyl group-containing linear organopolysiloxane (A1-2) preferably has a vinyl group content of 0.8 to 12 mol %.

[0131] Furthermore, when the first vinyl group-containing linear organopolysiloxane (A1-1) and the second vinyl group-containing linear organopolysiloxane (A1-2) are combined and blended, the ratio of (A1-1) to (A1-2) is not particularly limited, but for example, the weight ratio of (A1-1):(A1-2) is preferably 50:50 to 95:5, and more preferably 80:20 to 90:10.

[0132] The first and second vinyl group-containing linear organopolysiloxanes (A1-1) and (A1-2) may each be used alone or in combination of two or more.

[0133] The vinyl group-containing organopolysiloxane (A) may also contain a vinyl group-containing branched organopolysiloxane (A2) having a branched structure.

[0134] <<Organohydrogenpolysiloxane (B)>> The silicone rubber-based curable composition of this embodiment can contain an organohydrogenpolysiloxane (B). The organohydrogenpolysiloxane (B) is classified into a linear organohydrogenpolysiloxane (B1) having a linear structure and a branched organohydrogenpolysiloxane (B2) having a branched structure, and may contain either one or both of these.

[0135] The linear organohydrogenpolysiloxane (B1) has a linear structure and a structure in which hydrogen is directly bonded to Si (≡Si-H), and is a polymer that undergoes a hydrosilylation reaction with the vinyl groups of the vinyl group-containing organopolysiloxane (A) and with vinyl groups of the components blended into the silicone rubber-based curable composition, thereby crosslinking these components.

[0136] The molecular weight of the linear organohydrogenpolysiloxane (B1) is not particularly limited, but for example, the weight average molecular weight is preferably 20,000 or less, and more preferably 1,000 or more and 10,000 or less.

[0137] The weight average molecular weight of the linear organohydrogenpolysiloxane (B1) can be measured, for example, by gel permeation chromatography (GPC) using chloroform as a developing solvent, in terms of polystyrene.

[0138] Furthermore, it is generally preferred that the linear organohydrogenpolysiloxane (B1) does not contain a vinyl group, which can reliably prevent the crosslinking reaction from proceeding within the molecule of the linear organohydrogenpolysiloxane (B1).

[0139] As the linear organohydrogenpolysiloxane (B1) described above, for example, one having a structure represented by the following formula (2) is preferably used.

[0140] [ka]

[0141] In formula (2), R 4 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, a hydrocarbon group combining these, or a hydride group having 1 to 10 carbon atoms. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, and a propyl group, with a methyl group being preferred. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, and a butenyl group. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

[0142] Also, R 5 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, a hydrocarbon group combining these, or a hydride group having 1 to 10 carbon atoms. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, and a propyl group, with a methyl group being preferred. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, and a butenyl group. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

[0143] In addition, in formula (2), multiple R 4 are independent of each other and may be different or the same. 5 The same applies to multiple R 4 and R 5 At least two of these are hydride groups.

[0144] Also, R 6is a substituted or unsubstituted alkyl group or aryl group having 1 to 8 carbon atoms, or a hydrocarbon group combining these. Examples of alkyl groups having 1 to 8 carbon atoms include methyl groups, ethyl groups, and propyl groups, with methyl groups being preferred. Examples of aryl groups having 1 to 8 carbon atoms include phenyl groups. 6 are independent of each other and may be different from each other or may be the same.

[0145] In addition, R in formula (2) 4 ,R 5 ,R 6 Examples of the substituent include a methyl group and a vinyl group, and a methyl group is preferred from the viewpoint of preventing intramolecular crosslinking reactions.

[0146] Furthermore, m and n are the numbers of repeating units constituting the linear organohydrogenpolysiloxane (B1) represented by formula (2), where m is an integer of 2 to 150 and n is an integer of 2 to 150. Preferably, m is an integer of 2 to 100 and n is an integer of 2 to 100.

[0147] The linear organohydrogenpolysiloxane (B1) may be used alone or in combination of two or more.

[0148] Because the branched organohydrogenpolysiloxane (B2) has a branched structure, it forms regions with high crosslink density, and is a component that significantly contributes to the formation of a sparsely crosslinked structure in the silicone rubber system. Like the linear organohydrogenpolysiloxane (B1), it has a structure in which hydrogen is directly bonded to silicon (≡Si-H), and undergoes a hydrosilylation reaction with the vinyl groups of the vinyl-group-containing organopolysiloxane (A) and with the vinyl groups of other components incorporated into the silicone rubber-based curable composition, forming a polymer that crosslinks these components.

[0149] The specific gravity of the branched organohydrogenpolysiloxane (B2) is in the range of 0.9 to 0.95.

[0150] Furthermore, it is generally preferred that the branched organohydrogenpolysiloxane (B2) does not contain vinyl groups, which can reliably prevent crosslinking reactions from occurring within the molecules of the branched organohydrogenpolysiloxane (B2).

[0151] The branched organohydrogenpolysiloxane (B2) is preferably one represented by the following average composition formula (c).

[0152] Average composition formula (c) (H a (R 7 ) 3-a SiO 1 / 2 ) m (SiO 4 / 2 ) n (In formula (c), R 7 is a monovalent organic group, a is an integer ranging from 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)

[0153] In formula (c), R 7 is a monovalent organic group, preferably a substituted or unsubstituted alkyl group or aryl group having 1 to 10 carbon atoms, or a hydrocarbon group consisting of a combination thereof. Examples of alkyl groups having 1 to 10 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. Examples of aryl groups having 1 to 10 carbon atoms include phenyl groups.

[0154] In formula (c), a is the number of hydride groups (hydrogen atoms directly bonded to Si), and is an integer ranging from 1 to 3, preferably 1.

[0155] In addition, in formula (c), m is H a (R 7 ) 3-a SiO 1 / 2 The number of units, n, is SiO 4 / 2 The number of units.

[0156] The branched organohydrogenpolysiloxane (B2) has a branched structure. The linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) differ in their structures, that is, whether they are linear or branched. The number of alkyl groups R bonded to Si (R / Si), where the number of Si is 1, is in the range of 1.8 to 2.1 for the linear organohydrogenpolysiloxane (B1) and 0.8 to 1.7 for the branched organohydrogenpolysiloxane (B2).

[0157] Because the branched organohydrogenpolysiloxane (B2) has a branched structure, it leaves a residue amount of 5% or more when heated, for example, in a nitrogen atmosphere to 1000°C at a heating rate of 10°C / min. In contrast, because the linear organohydrogenpolysiloxane (B1) is linear, it leaves almost no residue amount after heating under the above conditions.

[0158] Specific examples of the branched organohydrogenpolysiloxane (B2) include those having a structure represented by the following formula (3).

[0159] [ka]

[0160] In formula (3), R 7 R is a substituted or unsubstituted alkyl group or aryl group having 1 to 8 carbon atoms, or a hydrocarbon group combining these, or a hydrogen atom. Examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. Examples of aryl groups having 1 to 8 carbon atoms include phenyl groups. 7 Examples of the substituent include a methyl group.

[0161] In addition, in formula (3), multiple R 7 are independent of each other and may be different from each other or may be the same.

[0162] In addition, in formula (3), "-O-Si≡" indicates that Si has a branched structure that spreads three-dimensionally.

[0163] The branched organohydrogenpolysiloxane (B2) may be used alone or in combination of two or more.

[0164] 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, the total amount of hydride groups in the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) is preferably 0.5 to 5 moles, more preferably 1 to 3.5 moles, per mole of vinyl groups in the vinyl group-containing linear organopolysiloxane (A1). This ensures the reliable formation of a crosslinked network between the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) and the vinyl group-containing linear organopolysiloxane (A1).

[0165] <<Silica particles (C)>> The silicone rubber-based curable composition of this embodiment may contain silica particles (C) as a non-conductive filler, if necessary.

[0166] The silica particles (C) are not particularly limited, but examples thereof include fumed silica, calcined silica, precipitated silica, etc. These may be used alone or in combination of two or more.

[0167] The silica particles (C) have a specific surface area of, for example, 50 to 400 m2 as measured by the BET method. 2 / g, and 100 to 400m 2 / g. The average primary particle size of the silica particles (C) is, for example, preferably from 1 to 100 nm, and more preferably from about 5 to 20 nm.

[0168] By using silica particles (C) having a specific surface area and average particle size within the above ranges, it is possible to improve the hardness and mechanical strength of the silicone rubber formed, particularly the tensile strength.

[0169] <<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, which is hydrolyzed by water to form a hydroxyl group, which 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).

[0170] The silane coupling agent (D) may also contain a silane coupling agent having a hydrophobic group. This imparts hydrophobic groups to the surfaces of the silica particles (C), thereby reducing the cohesive strength of the silica particles (C) in the silicone rubber-based curable composition and, ultimately, in the silicone rubber (reducing aggregation due to hydrogen bonding via silanol groups). This is thought to result in improved dispersibility of the silica particles in the silicone rubber-based curable composition. This increases the interface between the silica particles and the rubber matrix, enhancing the reinforcing effect of the silica particles. Furthermore, it is thought that the sliding properties of the silica particles within the matrix are improved during deformation of the rubber matrix. The improved dispersibility and sliding properties of the silica particles (C) contribute to improved mechanical strength (e.g., tensile strength, tear strength, etc.) of the silicone rubber.

[0171] Furthermore, the silane coupling agent (D) may contain a silane coupling agent having a vinyl group. This introduces a vinyl group onto the surface of the silica particles (C). Therefore, during curing of the silicone rubber-based curable composition, i.e., 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), thereby incorporating the silica particles (C) into the network. This allows for a silicone rubber with a low hardness and a high modulus to be formed.

[0172] 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.

[0173] Examples of the silane coupling agent (D) include those represented by the following formula (4).

[0174] Y n -Si-(X) 4-n ···(4) In the above formula (4), n represents an integer of 1 to 3. Y represents a functional group having 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 the groups is a hydrophobic group. X represents a hydrolyzable group.

[0175] The hydrophobic group is an alkyl group having 1 to 6 carbon atoms, an aryl group, or a hydrocarbon group formed by combining these groups, such as a methyl group, an ethyl group, a propyl group, or a phenyl group, with a methyl group being particularly preferred.

[0176] Examples of the hydrophilic group include a hydroxyl group, a sulfonic acid group, a carboxyl group, and a carbonyl group, and among these, a hydroxyl group is particularly preferred. Although a hydrophilic group may be contained as a functional group, it is preferable that the hydrophilic group is not contained from the viewpoint of imparting hydrophobicity to the silane coupling agent (D).

[0177] Further, examples of the hydrolyzable group include alkoxy groups such as methoxy and ethoxy groups, chloro groups, and silazane groups. Among these, silazane groups are preferred because of their high reactivity with the silica particles (C). Note that, those having a silazane group as the hydrolyzable group have structural characteristics such that (Y n -Si-) structures.

[0178] Specific examples of the silane coupling agent (D) represented by the above formula (4) include those having a hydrophobic group as a functional group, such as alkoxysilanes like methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, and decyltrimethoxysilane; chlorosilanes like methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, and phenyltrichlorosilane; and hexamethyldisilazane. Examples of the vinyl group-containing silane include alkoxysilanes such as methacryloxypropyltriethoxysilane, methacryloxypropyltrimethoxysilane, methacryloxypropylmethyldiethoxysilane, methacryloxypropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and vinylmethyldimethoxysilane; chlorosilanes such as vinyltrichlorosilane and vinylmethyldichlorosilane; and divinyltetramethyldisilazane. Among these, taking into consideration the above, hexamethyldisilazane is particularly preferred as the silane having a hydrophobic group, and divinyltetramethyldisilazane is particularly preferred as the silane having a vinyl group.

[0179] In this embodiment, the lower limit of the content of the silane coupling agent (D) 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 the vinyl group-containing organopolysiloxane (A). The upper limit of the content of the silane coupling agent (D) 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 the vinyl group-containing organopolysiloxane (A). By setting the content of the silane coupling agent (D) to the above lower limit or more, when silica particles (C) are used, it is possible to improve the mechanical strength of the silicone rubber as a whole. Also, by setting the content of the silane coupling agent (D) to the above upper limit or less, it is possible to provide the silicone rubber with appropriate mechanical properties.

[0180] <<Platinum or platinum compounds (E)>> The silicone rubber-based hardenable 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 curing. The amount of platinum or platinum compound (E) added is a catalytic amount.

[0181] As the platinum or platinum compound (E), known compounds can be used, such as platinum black, platinum supported on silica or carbon black, chloroplatinic acid or an alcohol solution of chloroplatinic acid, a complex salt of chloroplatinic acid and an olefin, and a complex salt of chloroplatinic acid and a vinylsiloxane.

[0182] The platinum or platinum compound (E) may be used alone or in combination of two or more.

[0183] <<Water(F)>> Furthermore, the silicone rubber-based hardening composition of this embodiment may contain water (F) in addition to the above components (A) to (E).

[0184] Water (F) functions as a dispersion medium to disperse the components contained in the silicone rubber-based curable composition, and also contributes to the reaction between the silica particles (C) and the silane coupling agent (D). This allows the silica particles (C) and the silane coupling agent (D) to be more reliably bonded to each other in the silicone rubber, allowing the composition to exhibit uniform properties overall.

[0185] Furthermore, when water (F) is contained, its content can be appropriately set, but specifically, for example, it is preferably in the range of 10 to 100 parts by weight, more preferably in the range of 30 to 70 parts by weight, per 100 parts by weight of the silane coupling agent (D), which allows the reaction between the silane coupling agent (D) and the silica particles (C) to proceed more reliably.

[0186] (Other ingredients) Furthermore, the silicone rubber-based curable composition of this embodiment may further contain other components in addition to the above components (A) to (F), such as inorganic fillers other than the 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, as well as additives such as reaction inhibitors, dispersants, pigments, dyes, antistatic agents, antioxidants, flame retardants, and thermal conductivity improvers.

[0187] The content ratio of each component in the silicone rubber-based hardening composition is not particularly limited, but may be set, for example, as follows:

[0188] In this embodiment, the upper limit of the content of silica particles (C) 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 good balance of mechanical strength, such as hardness and tensile strength. The lower limit of the content of silica particles (C) 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).

[0189] The silane coupling agent (D) is preferably contained in an amount of 5 to 100 parts by weight, more preferably 5 to 40 parts by weight, per 100 parts by weight of the vinyl group-containing organopolysiloxane (A), which ensures improved dispersibility of the silica particles (C) in the silicone rubber-based curable composition.

[0190] The content of organohydrogenpolysiloxane (B) is preferably 0.5 to 20 parts by weight, more preferably 0.8 to 15 parts by weight, per 100 parts by weight of the total of vinyl group-containing organopolysiloxane (A), silica particles (C), and silane coupling agent (D). By keeping the content of (B) within this range, a more effective curing reaction may be achieved.

[0191] The content of platinum or platinum compound (E) refers to the catalytic amount and can be set as appropriate. Specifically, it is an amount such that the platinum group metal in this component is 0.01 to 1000 ppm by weight, preferably 0.1 to 500 ppm, relative to the total amount of vinyl group-containing organopolysiloxane (A), silica particles (C), and silane coupling agent (D). By ensuring that the content of platinum or platinum compound (E) is at or above the lower limit, the resulting silicone rubber composition can be sufficiently cured. By ensuring that the content of platinum or platinum compound (E) is at or below the upper limit, the curing rate of the resulting silicone rubber composition can be improved.

[0192] Furthermore, when water (F) is contained, its content can be appropriately set, but specifically, for example, it is preferably in the range of 10 to 100 parts by weight, more preferably in the range of 30 to 70 parts by weight, per 100 parts by weight of the silane coupling agent (D), which allows the reaction between the silane coupling agent (D) and the silica particles (C) to proceed more reliably.

[0193] <Silicone rubber manufacturing method> Next, a method for producing the silicone rubber of this embodiment will be described. In the method for producing the silicone rubber of this embodiment, a silicone rubber-based curable composition is prepared, and the silicone rubber can be obtained by curing the silicone rubber-based curable composition. Details are provided below.

[0194] First, the components of the silicone rubber-based hardening composition are mixed uniformly using any kneading device to prepare the silicone rubber-based hardening composition.

[0195] [1] For example, a predetermined amount of vinyl group-containing organopolysiloxane (A), silica particles (C), and silane coupling agent (D) are weighed, and then kneaded using any kneading device to obtain a kneaded product containing these components (A), (C), and (D).

[0196] The kneaded mixture is preferably obtained by first kneading the vinyl group-containing organopolysiloxane (A) with the silane coupling agent (D) and then kneading (mixing) the silica particles (C), which further improves the dispersibility of the silica particles (C) in the vinyl group-containing organopolysiloxane (A).

[0197] Furthermore, when obtaining this kneaded mixture, water (F) may be added to the kneaded mixture of the components (A), (C), and (D) as needed, which allows the reaction between the silane coupling agent (D) and the silica particles (C) to proceed more reliably.

[0198] Furthermore, the kneading of components (A), (C), and (D) is preferably carried out through a first step in which the components are heated at a first temperature and a second step in which the components are heated at a second temperature. This allows the surfaces of the silica particles (C) to be surface-treated with the coupling agent (D) in the first step, and allows by-products formed by the reaction between the silica particles (C) and the coupling agent (D) to be reliably removed from the kneaded mixture in the second step. If necessary, component (A) may then be added to the resulting kneaded mixture, followed by further kneading. This improves the compatibility of the components in the kneaded mixture.

[0199] The first temperature is preferably, for example, about 40 to 120° C., and more preferably, for example, about 60 to 90° C. The second temperature is preferably, for example, about 130 to 210° C., and more preferably, for example, about 160 to 180° C.

[0200] 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.

[0201] Furthermore, the time for the first step is, for example, preferably about 0.3 to 1.5 hours, more preferably about 0.5 to 1.2 hours, and the time for the second step is, for example, preferably about 0.7 to 3.0 hours, more preferably about 1.0 to 2.0 hours.

[0202] By setting the conditions for the first and second steps as described above, the above-mentioned effects can be more significantly obtained.

[0203] [2] Next, predetermined amounts of organohydrogenpolysiloxane (B) and platinum or a platinum compound (E) are weighed out, and then, using any kneading device, components (B) and (E) are kneaded into the mixture prepared in step [1] above, thereby obtaining a silicone rubber-based curable composition. The obtained silicone rubber-based curable composition may be a paste containing a solvent.

[0204] When kneading components (B) and (E), it is preferable to first knead the mixture prepared in step [1] with the organohydrogenpolysiloxane (B), and then knead the mixture prepared in step [1] with platinum or a platinum compound (E), and then knead the respective mixtures together. This ensures that components (A) to (E) are dispersed in the silicone rubber-based curable composition without promoting the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B).

[0205] The temperature at which the components (B) and (E) are kneaded is, for example, preferably about 10 to 70°C, more preferably about 25 to 30°C, as the roll temperature.

[0206] Furthermore, the kneading time is, for example, preferably about 5 minutes to 1 hour, and more preferably about 10 to 40 minutes.

[0207] In steps [1] and [2], by maintaining the temperature within the above range, it is possible to more effectively prevent or inhibit the progress of the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B). Furthermore, by maintaining the kneading time within the above range in steps [1] and [2], it is possible to more reliably disperse the components (A) to (E) in the silicone rubber-based curable composition.

[0208] The kneading device used in each of steps [1] and [2] is not particularly limited, but for example, a kneader, a two-roll mill, a Banbury mixer (continuous kneader), a pressure kneader, etc. can be used.

[0209] Furthermore, in step [2], a reaction inhibitor such as 1-ethynylcyclohexanol may be added to the kneaded mixture, which makes it possible to more effectively prevent or inhibit the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) even when the temperature of the kneaded mixture is set at a relatively high temperature.

[0210] [3] Next, the silicone rubber-based hardening composition is hardened to form a silicone rubber.

[0211] In this embodiment, the curing step of the silicone rubber-based curable resin composition is carried out by, for example, 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).

[0212] By going through the above steps, a silicone rubber consisting of a cured product of the silicone rubber-based curable resin composition is obtained.

[0213] [3] Next, the silicone rubber-based curable composition obtained in step [2] is dissolved in a solvent to obtain an insulating paste. [3] Next, the silicone rubber-based curable composition obtained in step [2] is dissolved in a solvent, and a conductive filler is added to the solution, thereby obtaining a conductive paste.

[0214] (solvent) The conductive paste and the insulating paste contain a solvent. As the solvent, various known solvents can be used, including, for example, high-boiling point solvents, which may be used alone or in combination of two or more.

[0215] The lower limit of the boiling point of the high-boiling solvent is, for example, 100°C or higher, preferably 130°C or higher, and more preferably 150°C or higher. This can improve printing stability in screen printing and the like. On the other hand, the upper limit of the boiling point of the high-boiling solvent is not particularly limited, but may be, for example, 300°C or lower, 290°C or lower, or 280°C or lower. This can suppress excessive thermal history during wiring formation, thereby preventing damage to the substrate and maintaining a good shape of the wiring formed from the conductive paste.

[0216] The solvent can be appropriately selected from the viewpoint of the solubility and boiling point of the silicone rubber-based curable resin composition, and may include, for example, an aliphatic hydrocarbon having 5 to 20 carbon atoms, preferably an aliphatic hydrocarbon having 8 to 18 carbon atoms, and more preferably an aliphatic hydrocarbon having 10 to 15 carbon atoms.

[0217] Examples of the solvent 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; 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. Examples of such solvents include ethers 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 alone or in combination of two or more. The solvent used here may be appropriately selected from among solvents that can uniformly dissolve or disperse the components in the conductive paste.

[0218] The above solvents are the polarity term of the Hansen solubility parameters (δ p ) is, for example, 10 MPa 1 / 2 or less, preferably 7 MPa 1 / 2 or less, more preferably 5.5 MPa 1 / 2 The silicone rubber-based curable resin composition may contain a first solvent having the following polarity term (δ) of the first solvent. This makes it possible to improve the dispersibility and solubility of the silicone rubber-based curable resin composition in the paste. p The lower limit of the pressure is not particularly limited, but may be, for example, 0 Pa. 1 / 2 More than that is fine.

[0219] The hydrogen bond term (δ h ) is, for example, 20 MPa 1 / 2 or less, preferably 10 MPa 1 / 2 or less, more preferably 7 MPa 1 / 2 This allows the silicone rubber-based curable resin composition to have good dispersibility and solubility in the paste. h The lower limit of the pressure is not particularly limited, but may be, for example, 0 Pa. 1 / 2 More than that is fine.

[0220] Hansen solubility parameter (HSP) is an index that indicates the solubility of a substance, i.e., how much a substance dissolves in another substance. HSP expresses solubility as a three-dimensional vector. This three-dimensional vector is typically expressed as a dispersion term (δ d ), polarity term (δ p ), hydrogen bond term (δ h ) and those with similar vectors can be judged to have high solubility. The similarity of vectors can be judged by the distance of the Hansen solubility parameter (HSP distance).

[0221] The Hansen Solubility Parameters (HSP values) used in this specification can be calculated using software called HSPiP (Hansen Solubility Parameters in Practice). The computer software HSPiP, developed by Hansen and Abbott, includes a function for calculating HSP distances and a database listing the 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: polar term, H: hydrogen bond term, and R0: radius of the solubility sphere.

[0222] As the solvent of this embodiment, for example, one having a small difference in HSP distance, polarity term, or hydrogen bond term between the elastomer or the structural units constituting the elastomer and the solvent can be selected.

[0223] The lower limit of the viscosity of the conductive paste and / or insulating paste when measured at a shear rate of 20 [1 / s] at room temperature of 25°C is, for example, 1 Pa·s or more, preferably 5 Pa·s or more, and more preferably 10 Pa·s or more. This can improve film-forming properties. Also, shape retention can be improved even when forming a thick film. On the other hand, the upper limit of the viscosity of the conductive paste and / or insulating paste at room temperature of 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 can improve the printability of the paste.

[0224] At room temperature of 25°C, the viscosity measured at a shear rate of 1 [1 / s] is η1, the viscosity measured at a shear rate of 5 [1 / s] is η5, and the thixotropy index is the viscosity ratio (η1 / η5). In this case, the lower limit of the thixotropy index of the conductive paste and / or insulating paste is, for example, 1.0 or more, preferably 1.1 or more, and more preferably 1.2 or more. 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 index of the conductive paste and / or insulating paste is, for example, 3.0 or less, preferably 2.5 or less, and more preferably 2.0 or less. This allows the paste to be more easily printed.

[0225] 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. 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.

[0226] (Conductive filler) As the conductive filler, a known conductive material may be used, but metal powder (G) may also be used. The metal constituting the metal powder (G) is not particularly limited, but may include, for example, at least one of copper, silver, gold, nickel, tin, lead, zinc, bismuth, antimony, or metal powders alloyed with these, or two or more of these. Of these, the metal powder (G) preferably contains silver or copper, that is, silver powder or copper powder, because of their high conductivity and easy availability. These metal powders (G) may also be coated with other metals.

[0227] In this embodiment, the shape of the metal powder (G) is not limited, and conventionally used shapes such as dendritic, spherical, scale-like, etc. Among these, scale-like metal powder (G) may be used.

[0228] The particle size of the metal powder (G) is not limited, but for example, the average particle size D 50 The particle size of the metal powder (G) is, for example, an average particle size D 50 It 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 value of the thickness of the silicone rubber in this range, the silicone rubber can exhibit an appropriate electrical conductivity. The particle size of the metal powder (G) can be defined as the average particle size of 200 arbitrarily selected metal powder particles, for example, by observing the conductive paste or silicone rubber molded using the conductive paste with a transmission electron microscope or the like and performing image analysis.

[0229] The content of the conductive filler in the conductive paste is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more, based on the total weight of the conductive paste, and 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 weight of the conductive paste. By setting the content of the conductive filler to the above lower limit or more, the silicone rubber can have appropriate conductive properties, and by setting the content of the conductive filler to the above upper limit or less, the silicone rubber can have appropriate flexibility.

[0230] 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. 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 adjusting the content of the silicone rubber-based curable composition to be equal to or greater than the lower limit, the silicone rubber can have an appropriate degree of flexibility, while by adjusting the content of the silicone rubber-based curable composition to be equal to or less than the upper limit, the mechanical strength of the silicone rubber can be improved.

[0231] The lower limit of the content of the silica particles (C) in the conductive paste 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 the silica particles (C) and the conductive filler. This can improve the mechanical strength of the silicone rubber. On the other hand, the upper limit of the content of the silica particles (C) in the conductive paste 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 the silica particles (C) and the conductive filler. This can achieve a balance between the elastic electrical properties and the mechanical strength of the silicone rubber.

[0232] The lower limit of the amount of conductive filler in the conductive cured product obtained by curing the conductive paste that constitutes the stretchable sheet electrode 20 is, for example, 70% by mass or more, preferably 75% by mass or more, and more preferably 80% by mass or more, based on 100% by mass of the conductive cured product. This improves the stretchable electrical properties. On the other hand, the upper limit of the amount of conductive filler 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, based on 100% by mass of the conductive stretchable sheet electrode 20. This prevents a decrease in rubber properties such as stretchability.

[0233] The lower limit of the content of silica particles (C) in the conductive cured product obtained by curing the conductive paste that constitutes the stretchable sheet electrode 20 can be, for example, 1% by mass or more, preferably 3% by mass or more, and more preferably 4% by mass or more, relative to 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 content of silica particles (C) 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, relative to 100% by mass of the total amount of silica particles (C) and conductive filler. This can achieve a balance between the stretch electrical properties and the mechanical strength of the silicone rubber.

[0234] Next, a manufacturing process for the wearable bioelectrode 100 of this embodiment will be described.

[0235] The wearable bioelectrode of this embodiment includes a step of forming a flexible substrate 10 and a step of forming a stretchable sheet electrode 20 on the flexible substrate 10.

[0236] Here, an example of a manufacturing process for the wearable bioelectrode 100 will be described with reference to FIG. FIG. 5 is a cross-sectional view showing an outline of the manufacturing process of the wearable bioelectrode 100.

[0237] First, as shown in FIG. 5(a), a support is placed on a workbench, and an insulating paste is applied to the support. Various methods can be used for application, including, for example, a printing method using a squeegee. The insulating paste coating is then dried to form an insulating layer (flexible substrate 10 made of insulating elastomer) on the support. Drying conditions can be appropriately set depending on the type and amount of solvent in the insulating paste 13; for example, the drying temperature can be set to 150°C to 180°C, and the drying time can be set to 1 minute to 30 minutes.

[0238] The insulating layer constituting the flexible substrate may be formed by a molding method such as calendar molding or compression molding using the silicone rubber-based curable composition.

[0239] Next, as shown in Figure 5(b), a mask with a predetermined opening pattern is placed on the insulating layer, and then, as shown in Figures 5(b) and 5(c), a conductive paste is applied onto the insulating layer through the mask. The coating method can be the same as the method for coating the insulating paste, and for example, squeegee printing using a squeegee may be used. Here, when the insulating paste 3 and the conductive paste each contain a silicone rubber-based curable composition, a conductive coating (conductive layer) having a predetermined pattern may be laminated on the dried insulating layer, and then the two may be cured together. The curing process can be appropriately set depending on the silicone rubber-based curable composition, but for example, the curing temperature may be 160°C to 220°C, and the curing time may be 1 hour to 3 hours. After or before the curing process, the mask can be removed as shown in FIG. 5(d). This allows a cured conductive layer (stretchable sheet electrode 20 made of a conductive elastomer) having a predetermined pattern to be formed on the flexible substrate 10 made of the cured insulating layer. The support is then separated from the insulating layer. As a result of the above, the wearable bioelectrode 100 shown in FIG. 1 is obtained.

[0240] 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-based curable composition, the preparation method of the silicone rubber-based curable composition, etc. Among these, factors for achieving the desired ranges of hardness, tensile strength, elongation at break, and tear strength include 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 bond between the inorganic filler and 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 a vinyl group, and appropriately adjusting the content of the silica particles (C) and the content of the silane coupling agent.

[0241] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. [Example]

[0242] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the descriptions of these examples. The raw material ingredients shown in Table 1 are as follows: (A1-1): First vinyl group-containing linear organopolysiloxane: a vinyl group-containing dimethylpolysiloxane (structure represented by the above formula (1-1)) synthesized according to the following synthesis scheme 1. (A1-2): Second vinyl group-containing linear organopolysiloxane: A vinyl group-containing dimethylpolysiloxane (having the structure represented by the above formula (1-1) and R 1 and R 2 is a vinyl group)

[0243] (Organohydrogenpolysiloxane (B)) (B-1): Organohydrogenpolysiloxane: Momentive Corporation, "TC-25D"

[0244] (Silica particles (C)) (C): Silica microparticles (particle size 7 nm, specific surface area 300 m 2 / g), Nippon Aerosil Co., Ltd., "AEROSIL300"

[0245] (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)"

[0246] (Platinum or platinum compounds (E)) (E-1): Platinum compound (manufactured by Momentive, product name "TC-25A")

[0247] (Water(F)) (F):Pure water

[0248] (Metal powder (G)) (G1): Silver powder, manufactured by Tokuriki Chemical Laboratory Co., Ltd., product name "TC-101", median diameter d 50 :8.0μm, aspect ratio 16.4, average major axis 4.6μm

[0249] (Synthesis of vinyl group-containing organopolysiloxane (A)) [Synthesis Scheme 1: Synthesis of 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 siliconate were placed in a 300 mL separable flask equipped with a condenser and stirring blade and purged with Ar gas, and the mixture was heated to 120° C. and stirred for 30 minutes. An increase in viscosity was confirmed during this time. The temperature was then raised to 155°C and stirring was continued for 3 hours, after which 0.1 g (0.6 mmol) of 1,3-divinyltetramethyldisiloxane was added and the mixture was further stirred at 155°C for 4 hours. After another 4 hours, the mixture was diluted with 250 mL of toluene and washed three times with water. The washed organic layer was reprecipitated and purified by washing with 1.5 L of methanol several times, and the oligomer and polymer were separated. The resulting polymer was dried under reduced pressure at 60°C overnight to obtain a first vinyl group-containing linear organopolysiloxane (A1-1) (Mn = 2.2 × 10 5 , Mw=4.8×10 5 The vinyl group content calculated by H-NMR spectroscopy was 0.04 mol %.

[0250] [ka]

[0251] [Synthesis Scheme 2: Synthesis of Second Vinyl-Containing Linear Organopolysiloxane (A1-2)] A second vinyl group-containing linear organopolysiloxane (A1-2) was synthesized as shown in formula (6) below (Mn=2.3×10) by the same procedure as in the synthesis of (A1-1), except that 0.86 g (2.5 mmol) of 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane was used in addition to 74.7 g (252 mmol) of octamethylcyclotetrasiloxane. 5 , Mw=5.0×10 5 The vinyl group content calculated by H-NMR spectroscopy was 0.93 mol %.

[0252] [ka]

[0253] (Preparation of Silicone Rubber-Based Curable Composition) Silicone rubber-based curable compositions of Samples 1 to 4 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, and then silica particles (C) were added to the mixture and further kneaded to obtain a kneaded product (silicone rubber compound). Here, the kneading after adding the silica particles (C) was carried out through two steps: a first step of kneading for 1 hour under a nitrogen atmosphere at 60 to 90°C for the coupling reaction, and a second step of kneading for 2 hours under a reduced pressure atmosphere at 160 to 180°C for the removal of the by-product (ammonia).The mixture was then cooled, and the remaining 10% of the vinyl group-containing organopolysiloxane (A) was added in two portions, followed by kneading for 20 minutes. Next, organohydrogenpolysiloxane (B), platinum or a platinum compound (E) were added to 100 parts by weight of the obtained kneaded product (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.

[0254] (Preparation of conductive paste) 13.7 parts by weight of the obtained silicone rubber-based curable composition of Sample 4 was immersed in 31.8 parts by weight of tetradecane (solvent), then stirred with a planetary centrifugal mixer, 54.5 parts by weight of metal powder (G1) was added, and then kneaded with a triple roll mill to obtain conductive paste 1.

[0255] [Table 1]

[0256] (Fabrication of wearable bioelectrodes) The obtained silicone rubber-based curable compositions of Samples 1 to 3 were pressed at 170°C and 10 MPa for 10 minutes to form a sheet with a thickness of 150 μm, and the sheet was subjected to primary curing. Subsequently, secondary curing was performed at 200°C for 4 hours to obtain a sheet-like silicone rubber (cured product of the silicone rubber-based curable composition) with a hardness of 70. The obtained sheet-like silicone rubber was cut into a width of 2 cm and a length of 24 cm to prepare a flexible substrate. Using the obtained conductive paste 1, a rectangular stretchable sheet electrode having a width of 20 mm, a length of 24 mm, and a thickness of 0.05 mm, a linear stretchable wiring, and a rectangular connecting part were drawn on one side of a flexible substrate through a mask having a predetermined pattern, and the electrode was dried at 140°C for 20 minutes and cured at 180°C for 2 hours. An external connection part (a male metal snap button) was attached to the other surface of the flexible substrate, and the external connection part was electrically connected to the connection part of the stretchable sheet electrode to obtain the wearable bioelectrodes of Examples 1 to 3.

[0257] The obtained wearable bioelectrode was evaluated for the following items. The results are shown in Table 2.

[0258] [Table 2]

[0259] (hardness) The silicone rubber-based curable compositions of Samples 1 to 3 used in the flexible substrate were pressed at 170°C and 10 MPa for 10 minutes to form them into sheets, which were then subjected to primary curing. Subsequently, secondary curing was performed at 200°C for 4 hours, and the resulting flexible substrates (cured products of the silicone rubber-based curable compositions) with a thickness of 150 μm were used as test specimens. The above test pieces were stacked to a thickness of 6 mm, and the durometer hardness A of the resulting sheet-like test piece at 25° C. was measured in accordance with JIS K6253 (1997). (tear strength) Using the above test piece, the tear strength at 25°C was measured in accordance with JIS K6252 (2001), with the unit being N / mm. (tensile strength) Using the above test pieces, the tensile strength at 25°C was measured in accordance with JIS K6251 (2004), with the unit being MPa. (Elongation at break) The test specimens were used to measure the elongation at break in accordance with JIS K6251 (2004). The elongation at break was calculated by [movement distance between chucks (mm)] ÷ [initial distance between chucks (35 mm)] × 100. The unit is %.

[0260] (resistance value, volume resistivity) Using the wearable bioelectrode of each example, the resistance and volume resistivity of the unstretched region or the diagonal of the rectangular stretchable sheet electrode in the stretched region were measured in an environment of 25°C when unstretched or when stretched 50% in the diagonal direction of the rectangular stretchable sheet electrode. In Example 1, the resistance (R1) of the stretchable sheet electrode when unstretched at 25°C was 0.8Ω, the resistance (R2) of the stretchable sheet electrode when stretched 50% at 25°C was 2.6Ω, R2 / R1 was 3.3, and the surface resistivity of the stretchable sheet electrode when unstretched at 25°C was 4.3 × 10 -3 Ω / □, 25℃, volume resistivity of the stretchable sheet electrode when unstretched is 2.4×10 -4 The resistance was Ω·cm.

[0261] (bioelectric potential measurement) Three wearable bioelectrodes of each example were prepared, and each of the external connection parts of the three wearable bioelectrodes was connected to BITalino (manufactured by Plux) via an electrode cable with a connector (female snap button) and an ECG sensor (manufactured by Plux) to create an electrocardiogram measurement system. The stretchable sheet electrodes on one side of the three wearable bioelectrodes were attached directly to the subject's skin, and the subject's cardiac potential was measured using a three-point lead method (measurement point, reference point, body earth). As a result, it was confirmed that electrocardiogram waveforms (electrocardiograms) could be monitored.

[0262] (deformation durability) The wearable bioelectrodes obtained in each example were stretched 10 times by 20% or 50%, and then used to measure cardiac potentials. It was confirmed that electrocardiographic waveforms could be monitored without any problems. It was also confirmed that no peeling occurred between the flexible substrate and the stretchable sheet electrode even after repeated stretching at 20% or 50% stretch.

[0263] (Wearability) The flexible substrate of the wearable bioelectrode of each example obtained above was sewn to the chest area of ​​a T-shirt with sewing thread. The subject put on and took off the T-shirt with the wearable bioelectrode sewn on multiple times. It was confirmed that the wearable bioelectrode conformed to the subject's chest when worn and did not peel off from the T-shirt after being worn or removed. In addition, the wearing sensation of multiple subjects was generally described as "there is a sense of contact, but it is not bothersome" and "there is no pain, but it feels strange," confirming that the wearing sensation is relatively small.

[0264] (Washing durability) The peripheral portion of the flexible substrate of the wearable bioelectrode of each example obtained above, where the stretchable sheet electrode was not formed, was sewn to a cloth with thread using a sewing machine to prepare an evaluation device B1. Evaluation device B2 was produced in the same manner as evaluation device B1, except that a cured product of a silicone rubber-based curable composition having a hardness of 30 was used as the flexible substrate. In the evaluation devices B1 and B2, no damage such as cracks was observed around the flexible substrate portion that had been subjected to the sewing treatment.

[0265] Washing durability test: Using a household washing machine, the garment is washed, rinsed 1, rinsed 2, and then hung to dry in accordance with JIS L1930 (C4M method), and the test is repeated 10 times. It was confirmed that the resistance value fluctuation was small when evaluation devices B1 and B2 were stretched 100 times by 20% and 100 times by 50% before and after the washing durability test.

[0266] The wearable bioelectrodes of Examples 1 to 3 showed excellent results in terms of durability against deformation and the like.

[0267] Examples 4 to 7 The obtained silicone rubber-based curable composition of Sample 1 was pressed at 170°C and 10 MPa for 10 minutes to form it into a sheet, which was then subjected to primary curing and secondary curing at 200°C for 4 hours to obtain two types of sheet-shaped silicone rubber (cured products of the silicone rubber-based curable composition) with different thicknesses (X). The two types of silicone rubber sheets were cut into pieces of width: 2 cm x length: 24 cm, to prepare flexible substrates with thicknesses (X) of 150 μm and 300 μm. Using the obtained conductive paste 1, a rectangular stretchable sheet electrode having a width of 20 mm, a length of 24 mm, and a thickness (Y) of the values ​​(μm) listed in Table 3 was drawn on one side of a flexible substrate using masks of different thicknesses, and the electrode was dried at 140°C for 20 minutes and cured at 180°C for 2 hours. In this manner, the wearable bioelectrodes of Examples 4 to 7 were obtained.

[0268] The wearable bioelectrode was cut in the stacking direction, and one of the cross sections was observed with an electron microscope to obtain an SEM image. Based on the SEM image, the thickness of the flexible substrate (X) and the thickness of the stretchable sheet electrode (Y) were measured.

[0269] [Table 3]

[0270] (washing resistance) The wearable bioelectrodes of Examples 4 to 7 were subjected to the following washing durability test. 1. Repeatedly stretch and contract the wearable bioelectrode by 50% in both the vertical and horizontal directions 300 times. 2. Neutral detergent and water were placed in a beaker, the wearable bioelectrode treated in step 1 was immersed, and the mixture was stirred for 24 hours. 3. Pour water into a beaker, immerse the wearable bioelectrode treated in step 2, stir for 10 minutes, and rinse off the detergent. 4. Dry in a 90°C oven for 30 minutes. The above steps 1 to 4 were repeated 10 times. In Examples 4 to 7, it was confirmed that when 20% elongation was repeated 100 times and when 50% elongation was repeated 100 times, the change in resistance value before and after the washing durability test was small in both cases. Furthermore, it was confirmed that in Examples 4 to 7, no cracks occurred in the stretchable sheet electrode, and no peeling occurred between the stretchable sheet electrode and the flexible substrate, and the initial state was maintained. Furthermore, when electrocardiogram waveforms were measured using the wearable bioelectrodes after the washing durability test, cases where the electrocardiogram waveforms could be measured with almost no change from before the washing durability test were evaluated as ◎, and cases where the electrocardiogram waveforms could be measured without any problems but there was a slight increase in noise compared to before the washing durability test were evaluated as ○. The results are shown in Table 3.

[0271] The wearable bioelectrodes of Examples 4 to 7 showed results in which washing resistance was improved by appropriately selecting the thickness of the flexible substrate and the thickness of the stretchable sheet electrode. [Explanation of symbols]

[0272] 10,10a Flexible base material 11 one side 12 Main Unit 13 Other side 14 Extension 20, 20a, 20b, 20c Stretchable sheet electrodes 22 one side 24 Stretchable wiring 26 Connection 30 External connection part 32 Mounting plate 34 Mounting pin 50 protective layer 52 Insulating protective layer 100,100a Wearable Bioelectrode 200 Biometric Sensor 210 Connector 220 Cable 230 Sensor Module 240 Computers

Claims

1. A flexible substrate; a stretchable sheet electrode including a conductive elastomer provided on the flexible substrate; Equipped with Wearable bioelectrodes.

2. 10. The wearable bioelectrode according to claim 1, A wearable bioelectrode used to measure at least one bioelectric potential of cardiac potential, myoelectric potential, and skin potential.

3. 3. The wearable bioelectrode according to claim 1, The volume resistivity of the stretchable sheet electrode at 25°C when unstretched is 1.0 × 10 －５ Ω・cm or more 9.0×10 ２ A wearable bioelectrode with a resistance of Ω·cm or less.

4. The wearable bioelectrode according to any one of claims 1 to 3, The surface resistivity of the stretchable sheet electrode at 25°C when unstretched is 1.0 x 10 －４ Ω / □ or more 9.0×10 ５ A wearable bioelectrode having a resistance of Ω / □ or less.

5. The wearable bioelectrode according to any one of claims 1 to 4, When the resistance value of the stretchable sheet electrode at 25°C when unstretched is R1 and the resistance value of the stretchable sheet electrode at 25°C when stretched 50% is R2, A wearable bioelectrode configured such that R1 and R2 satisfy 1.5≦R2 / R1≦20.

6. The wearable bioelectrode according to any one of claims 1 to 5, The wearable bioelectrode, wherein the stretchable sheet electrode is composed of a printed layer of conductive paste.

7. The wearable bioelectrode according to any one of claims 1 to 4, The wearable bioelectrode, wherein the stretchable sheet electrode contains silver powder.

8. 8. The wearable bioelectrode according to claim 7, A wearable bioelectrode, wherein the silver powder comprises scale-shaped silver powder.

9. 9. The wearable bioelectrode according to claim 7 or 8, The wearable bioelectrode, wherein the stretchable sheet electrode contains silica particles.

10. 10. The wearable bioelectrode according to claim 9, A wearable bioelectrode, wherein the content of the silica particles in the stretchable sheet electrode is 1% by mass or more and 20% by mass or less, relative to 100% by mass of the total amount of the silica particles and silver powder.

11. A wearable bioelectrode according to any one of claims 1 to 10, A wearable bioelectrode, wherein the flexible substrate has a band shape that can be wrapped around the body.

12. A wearable bioelectrode according to any one of claims 1 to 11, A wearable bioelectrode that can be attached to either the body or clothing.

13. A wearable bioelectrode according to any one of claims 1 to 12, Washable, wearable bioelectrodes.

14. A wearable bioelectrode according to any one of claims 1 to 13, A wearable bioelectrode, wherein the thickness of the flexible substrate is 10 mm or less.

15. A wearable bioelectrode according to any one of claims 1 to 14, A wearable bioelectrode comprising an external connection part provided on the flexible substrate on the side opposite to the stretchable sheet electrode, the external connection part being electrically connected to the stretchable sheet electrode.

16. A wearable bioelectrode according to any one of claims 1 to 15, the flexible substrate comprises an insulating elastomer; A wearable bioelectrode, wherein the stretchable sheet electrode is provided on one surface of the flexible substrate.

17. 17. A wearable bioelectrode according to claim 16, A wearable bioelectrode, wherein the insulating elastomer has a tear strength of 25 N / mm or more when measured at 25°C in accordance with JIS K6252 (2001).

18. 18. A wearable bioelectrode according to claim 16 or 17, A wearable bioelectrode, wherein the insulating elastomer has a breaking elongation of 500% or more when measured at 25°C in accordance with JIS K6251 (2004).

19. A wearable bioelectrode according to any one of claims 16 to 18, A wearable bioelectrode, wherein the insulating elastomer has a tensile strength of 5.0 MPa or more, measured at 25°C in accordance with JIS K6251 (2004).

20. The wearable bioelectrode according to any one of claims 16 to 19, A wearable bioelectrode, wherein the insulating elastomer has a durometer hardness A of 20 or more as measured at 25°C in accordance with JIS K6253 (1997).

21. A wearable bioelectrode according to any one of claims 16 to 20, 1. A wearable bioelectrode, wherein the insulating elastomer and the conductive elastomer comprise the same elastomer material.

22. A wearable bioelectrode according to any one of claims 1 to 21, When the thickness of the flexible substrate is X and the thickness of the stretchable sheet electrode is Y, A wearable bioelectrode configured such that X and Y satisfy 0.15≦Y / X≦1.

1.

23. A biosensor comprising the wearable bioelectrode according to any one of claims 1 to 22.

24. A biosignal measurement system comprising the biosensor according to claim 23.

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