Flexible sheet electrode, wearable biometric electrode, and biosensor

Abstract

To provide a flexibility sheet electrode having excellent measurement stability.SOLUTION: A flexibility sheet electrode according to the present invention comprises a flexibility substrate and a conductive elastomer layer arranged on the flexibility substrate. When the arithmetical average height on a surface of the conductive elastomer layer when elongated by 20% is set to Sa20, and the maximum height is set to Sz20, the electrode is configured to satisfy Sa20≤21.0 μm and / or Sz20≤250 μm.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Various developments have been made on sheet electrodes so far. As this type of technology, for example, the technology described in Patent Document 1 is known. Patent Document 1 describes an electrode member characterized in that a conductive polymer is supported on the surface of single fibers constituting a fiber structure and / or in the gaps between single fibers (Claim 1 etc. of Patent Document 1). In the examples of the same document, regarding the method of supporting a conductive polymer on a fiber structure, a dispersion liquid in which a conductive polymer such as PEDOT / PSS and a binder are dispersed in a solvent is gravure-coated on the fiber structure so that the coating amount is about 15 g / m 2 (about 1.5 mg / cm 2 ).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the electrode member of Patent Document 1 above, sufficient consideration has not been given to the configuration using a conductive elastomer layer as a sheet-like electrode portion.

[0005] As a result of investigations by the present inventor, it has been found that there is room for improvement in terms of measurement stability in a sheet electrode having a conductive elastomer layer.

Means for Solving the Problems

[0006] As a result of further study by the present inventor, it has been found that the stability in measurement using a flexible sheet electrode can be evaluated by using, as an index, the arithmetic mean height and the maximum height on the surface of the conductive elastomer layer at 20% elongation. Based on such findings, further intensive studies were conducted. As a result, by setting the arithmetic mean height (Sa 20 ) and / or the maximum height (Sz 20 ) on the surface of the conductive elastomer layer at 20% elongation to a predetermined value or less, it has been found that the measurement stability in the flexible sheet electrode can be improved from the results such as suppression of noise when measuring a bioelectric potential, and the present invention has been completed.

[0007] According to the present invention, a flexible substrate, a conductive elastomer layer provided on the flexible substrate, A flexible sheet electrode comprising: wherein, when the arithmetic mean height on the surface of the conductive elastomer layer at 20% elongation measured by a laser microscope having a laser light wavelength of 404 nm is defined as Sa 20 and the maximum height is defined as Sz 20 , Sa 20 ≤ 21.0 μm and / or Sz 20 ≤ 250 μm are satisfied, A flexible sheet electrode is provided.

[0008] Also according to the present invention, A wearable bioelectrode comprising the above flexible sheet electrode is provided.

[0009] Also according to the present invention, A biosensor comprising the above wearable bioelectrode is provided.

Advantages of the Invention

[0010] According to the present invention, there are provided a flexible sheet electrode excellent in measurement stability, a wearable bioelectrode using the same, and a biosensor.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. Further, the drawings are schematic views and do not match the actual dimensional ratios.

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

[0014] The flexible sheet electrode of the present embodiment includes a flexible base material and a conductive elastomer layer provided on the flexible base material, and the arithmetic mean height Sa on the surface of the conductive elastomer layer at 20% elongation measured by a laser microscope having a laser light wavelength of 404 nm 20 is defined as, and the maximum height Sz 20 is defined as, when Sa 20 ≦21.0 μm and / or Sz 20 ≦250 μm.

[0015] The arithmetic mean height Sa represents the average of the absolute values of the height differences of each point with respect to the average plane of the two-dimensional surface. The maximum height Sz represents the distance from the highest point to the lowest point on the two-dimensional surface.

[0016] According to the findings of the present inventor, in a conductive elastomer layer functioning as an electrode, by making the arithmetic mean height (Sa 20 ) and / or the maximum height (Sz 20 ) on the surface at 20% elongation equal to or less than the above upper limit value, it has been found that noise during measurement of the bioelectric potential can be suppressed and the measurement stability in the flexible sheet electrode can be improved. Although the detailed mechanism is not clear, it is considered that by appropriately smoothing the surface of the conductive elastomer layer in the stretched state, noise during measurement of the bioelectric potential can be suppressed in an actual measurement scenario where the flexible sheet electrode follows the surface of the measurement target for measurement.

[0017] The flexible sheet electrode can be applied to various uses, and one of them is a wearable bioelectrode. The wearable bioelectrode of the present embodiment includes the above flexible sheet electrode.

[0018] According to the present embodiment, a wearable bioelectrode can be realized in which noise in the electrocardiogram waveform is suppressed and the S-T segment becomes clear. The height of the S-T segment is an important factor for discriminating heart abnormalities. For example, if the height of the S-T segment is lower, there may be angina pectoris, and if it is higher, there may be myocardial infarction.

[0019] The wearable bioelectrode can detect potential fluctuations from a living body such as a heartbeat, muscle activity, and nervous system activity. For example, the wearable bioelectrode may be configured to be used for measuring at least one of a bioelectric potential such as an electrocardiogram potential, an electromyogram potential, and a skin potential.

[0020] According to the present embodiment, a wearable bioelectrode that can be stretched and / or bent can be realized. Even when such a wearable bioelectrode is deformed such as stretching or bending of the base material, disconnection in the flexible sheet electrode is suppressed, and stable measurement of the bioelectric potential becomes possible. Also, even when the base material is deformed, the occurrence of peeling of the flexible sheet electrode from the flexible base material is suppressed, and the adhesion between them is maintained.

[0021] The wearable bioelectrode can be used as a wearable device that can be worn on either the body or the clothing. Due to its stretchability, such a wearable bioelectrode can follow the surface shape of the body and the body movements. In this case, the wearable bioelectrode may be directly worn on the body or worn on the body via a body-wearing member (clothing). The clothing with the wearable bioelectrode has, for example, a configuration in which the wearable bioelectrode is sewn onto the clothing or a configuration in which the wearable bioelectrode is used for a part of the clothing.

[0022] The wearable bioelectrode can further include a connector, electronic components, etc., and can constitute a biosensor that can be connected to an external device. This biosensor is wearable. By analyzing the bioelectric potential such as the electrocardiogram potential detected by the biosensor, a bio-signal measurement system corresponding to various applications can be constructed.

[0023] Such wearable bioelectrodes, biosensors using them, and bio-signal measurement systems are expected to be used in various scenes such as body diagnosis, health management, fitness, rehabilitation, and nursing care.

[0024] Hereinafter, the configuration of the flexible sheet electrode and the wearable bioelectrode of the present embodiment will be described in detail.

[0025] <Flexible Sheet Electrode> FIG. 1 is a top view showing an example of the configuration of the flexible sheet electrode 1. FIG. 1(a) is a cross-sectional view taken along line A-A of (b) of the flexible sheet electrode 1, and (b) is a top view of the flexible sheet electrode 1.

[0026] The flexible sheet electrode 1 includes a flexible base material 10 and a conductive elastomer layer 20 provided on the flexible base material 10.

[0027] On the surface (one surface 22) of the conductive elastomer layer 20 in FIG. 1(a), the arithmetic mean height when not stretched is defined as Sa0, and the maximum height is defined as Sz0. The arithmetic mean height in the state where the surface is stretched by 20% is defined as Sa 20, and the maximum height is Sz 20 Let it be so.

[0028] Sa 20 The upper limit value of is, for example, 19.5 μm or less, preferably 18.5 μm or less, more preferably 12.0 μm or less. Thereby, the measurement stability of the flexible sheet electrode 1 can be improved. On the other hand, Sa 20 The lower limit is not particularly limited, but may be 0.5 μm or more, or may be 1 μm or more.

[0029] Sz 20 The upper limit value of is, for example, 200 μm or less, preferably 190 μm or less, more preferably 80 μm or less. Thereby, the measurement stability of the flexible sheet electrode 1 can be improved. On the other hand, Sz 20 The lower limit is not particularly limited, but may be 1 μm or more, or may be 5 μm or more.

[0030] The flexible sheet electrode 1 may be configured to satisfy 0 μm ≦ |Sa 20 - Sa0| ≦ 10 μm, and / or 0 μm ≦ |Sz 20 - Sz0| ≦ 80 μm.

[0031] |Sa 20 - Sa0| The upper limit is, for example, 10 μm or less, preferably 8 μm or less, more preferably 5 μm or less. Thereby, the measurement stability of the flexible sheet electrode 1 can be improved.

[0032] |Sz 20 - Sz0| The upper limit is, for example, 80 μm or less, preferably 60 μm or less, more preferably 50 μm or less. Thereby, the measurement stability of the flexible sheet electrode 1 can be improved.

[0033] The arithmetic mean height Sa W0 on the surface of the conductive elastomer layer 20 at the time of non-elongation measured by a laser microscope having a laser light wavelength of 404 nm after repeating the washing process 20 times according to the following procedures (1) to (4), and the maximum height is Sz W0 Let it be so. (Procedure of washing treatment) 1. Repeatedly stretch and contract the flexible sheet electrode 50% 300 times in the vertical and horizontal directions respectively. 2. Put neutral detergent and water into a beaker, immerse the flexible sheet electrode treated in 1, and stir for 24 hours. 3. Put water into a beaker, immerse the flexible sheet electrode treated in 2, stir for 10 minutes, and rinse the detergent. 4. Dry in an oven at 90 °C for 30 minutes.

[0034] The flexible sheet electrode 1 may be configured to satisfy Sa W0 ≤ 16.0 μm, and / or Sz W0 ≤ 250 μm.

[0035] Sa w0 The upper limit value of is, for example, 16.0 μm or less, preferably 14.0 μm or less, more preferably 7 μm or less. Thereby, the measurement stability of the flexible sheet electrode 1 can be improved. On the other hand, the lower limit of Sa w0 is not particularly limited, but may be 0.5 μm or more, or may be 1 μm or more.

[0036] Sz w0 The upper limit value of is, for example, 250 μm or less, preferably 200 μm or less, more preferably 80 μm or less. Thereby, the measurement stability of the flexible sheet electrode 1 can be improved. On the other hand, the lower limit of Sz w0 is not particularly limited, but may be 1 μm or more, or may be 5 μm or more.

[0037] The lower limit of the adhesion amount of the conductive elastomer layer 20 is, for example, 15 mg / cm 2 or more, preferably 30 mg / cm 2 or more, more preferably 40 mg / cm 2 or more. Thereby, the conductivity can be enhanced. The upper limit of the adhesion amount of the conductive elastomer layer 20 is, for example, 300 mg / cm 2 or less, preferably 250 mg / cm 2More preferably, it is 200 mg / cm 2 or less. Thereby, a decrease in the flexibility of the flexible sheet electrode can be suppressed.

[0038] The conductive elastomer layer 20 has stretchability.

[0039] In this specification, the stretchability is represented by the elongation rate when stretched in a predetermined direction. As the predetermined direction, for example, in the top view of FIG. 1, the direction in which the conductive elastomer layer 20, specifically, the conductive elastomer layer 20 has the maximum length may be adopted. When the top view shape of the conductive elastomer layer 20 is a square shape, the arithmetic mean height (Sa 20 ) and the maximum height (Sz 20 ) may be measured by grasping two opposite sides and stretching them in the plane direction, and may be stretched in the diagonal direction when measuring the surface resistivity.

[0040] When stretched in the above-described extending direction, having stretchability means that the elongation rate can be extended, for example, by 10% or more, preferably 20% or more, more preferably 50% or more, and the conductive elastomer layer 20 does not break at that elongation rate.

[0041] When the surface resistance value of the conductive elastomer layer 20 at 25°C and when not stretched is R1, and the surface resistance value of the conductive elastomer layer 20 at 25°C and when stretched by 20% in one of the in-plane directions of the surface is R2, R1 and R2 are configured to satisfy 1.0 ≦ R2 / R1 ≦ 7.0.

[0042] The upper limit of R2 / R1 is, for example, 7.0 or less, preferably 6.5 or less, more preferably 5.0 or less. Thereby, the measurement stability can be enhanced. On the other hand, the lower limit of R2 / R1 is not particularly limited, but may be 1.0 or more, preferably 1.1 or more. Also, the upper limit of R2 is, for example, 30 Ω or less, preferably 20 Ω or less, more preferably 15 Ω or less. On the other hand, the lower limit of R2 may be, for example, 0.5 Ω or more.

[0043] Note that the resistance measurement such as surface resistivity may be performed between any two points. However, when the top view shape of the conductive elastomer layer 20 is rectangular, it may be performed at the diagonals of the conductive elastomer layer 20.

[0044] The conductive elastomer layer 20 is formed using a conductive elastomer described later. Also, the conductive elastomer layer 20 may be formed by a printing method using a conductive paste containing a conductive elastomer. That is, an example of the conductive elastomer layer 20 is composed of a printed layer of a conductive paste. Therefore, a flexible sheet electrode with excellent design freedom in sheet electrode design can be provided.

[0045] The flexible base material 10 is not particularly limited as long as it is a base material that can be stretched and / or bent. For example, it may be composed of a fiber base material or an elastomer base material.

[0046] Examples of the fiber structure material of the fiber base material include natural fibers such as plant fibers and animal fibers; chemical fibers such as inorganic fibers, recycled fibers, semi-synthetic fibers, and synthetic fibers. These may be used alone or in combination of two or more. Among these, from the viewpoint of durability, chemical fibers may be used, and synthetic fibers such as acrylic, polyester, nylon, and polyurethane may be used.

[0047] As the fiber base material, a known fiber base material can be used. For example, it may be composed of either one or both of an insulating material and a conductive material.

[0048] The lower limit of the basis weight of the fiber base material is, for example, 10 g / m 2 or more, preferably 20 g / m 2 or more, more preferably 30 g / m 2 or more. Thereby, the mechanical strength can be enhanced. On the other hand, the upper limit of the basis weight of the fiber base material is, for example, 500 g / m 2 or less, preferably 400 g / m 2 or less, more preferably 350 g / m2 The following is the case. By this, a decrease in flexibility can be suppressed. In addition, the impregnation degree of the conductive elastomer layer can be increased.

[0049] The elastomer base material may be composed of an insulating elastomer described later. Further, the elastomer base material may be a porous elastomer base material, an elastomer base material having irregularities on the surface, or the like.

[0050] The structure of the fiber base material is not limited, but from the viewpoint of flexibility, a woven fabric or a knitted fabric may be used.

[0051] The upper limit of the thickness of the flexible base material 10 can be set according to the application. For example, it may be 10 mm or less, preferably 1 mm or less, but from the viewpoint of wearable device applications, it is more preferably 600 μm or less. By setting it to 600 μm or less, a thin film sheet-like wearable bioelectrode can be realized. The lower limit of the thickness of the flexible base material 10 is, from the viewpoint of mechanical strength, for example, 10 μm or more, preferably 50 μm or more, more preferably 100 μm or more.

[0052] An example of the manufacturing method of the flexible sheet electrode 1 of the present embodiment includes a step of impregnating the flexible base material 10 with a conductive elastomer material. The form of the conductive elastomer material may be a paste or a film. The impregnation method can be selected from known methods according to the form. Examples of the impregnation method include screen processing, dipping processing, coating processing, calendar processing, lamination processing, vacuum impregnation processing, etc. In these processes, it is possible to introduce the conductive elastomer material into the flexible base material 10 using a blade, a roller, a press, etc., and heating if necessary.

[0053] As a specific example of the manufacturing method of the flexible sheet electrode 1, an example of screen processing using a conductive paste as the conductive elastomer material and a squeegee will be described. First, a support is placed on a workbench, and the flexible base material 10 is placed on the support. Subsequently, a mask having a predetermined opening pattern shape is disposed on the flexible substrate 10. Subsequently, a conductive paste is applied onto the flexible sheet electrode 1 through the mask using a squeegee. Thereafter, the conductive paste is subjected to a curing treatment. For example, in the case of a conductive paste containing a silicone rubber-based curable composition, the curing temperature can be set to 160°C to 220°C and the curing time can be set to 1 hour to 3 hours, etc. The mask is removed after or before the curing treatment. Thereafter, the flexible substrate 10 support is separated to obtain the flexible sheet electrode 1.

[0054] In the present embodiment, for example, by appropriately selecting the method for producing the flexible sheet electrode 1 or the like, the Sa 20 , Sa0, Sz 20 , Sz0, and the adhesion amount can be controlled. Among these, for example, appropriately selecting the thickness of the mask, the number of mask laminations, the number of coating times, the solid content concentration of the conductive paste, etc. are factors for setting the Sa 20 , Sa0, Sz 20 , Sz0, and the adhesion amount within a desired numerical range.

[0055] A modified example of the flexible sheet electrode 1 will be described with reference to FIG. 2.

[0056] The flexible substrate 10 may be configured such that a part thereof includes the impregnated layer 21 of the conductive elastomer layer 20 as shown in FIG. 2(a) with respect to the thickness direction, or the whole thereof may be configured to include the impregnated layer 21. Thereby, a flexible sheet electrode 1 excellent in washing resistance can be realized.

[0057] Further, as shown in FIG. 2(b), the flexible substrate 10 may have an insulating elastomer layer 60 on the surface opposite to the surface having the conductive elastomer layer 20. The insulating elastomer layer 60 may be partially or entirely impregnated into the flexible substrate 10. The insulating elastomer layer 60 may be composed of an insulating elastomer described later.

[0058] <Wearable bioelectrode> FIG. 3 is a top view showing an example of the configuration of the wearable bioelectrode 100. FIG. 4 is a cross-sectional view taken along line B-B of FIG. 3. The wearable bioelectrode 100 includes a flexible sheet electrode 1 having a flexible base material 10 and a conductive elastomer layer 20.

[0059] The wearable bioelectrode 100 can detect bioelectric signals generated from bioactivities such as the heart, muscles, skin, and nerves by causing one surface 22 of the conductive elastomer layer 20 to follow the body of the subject. When the wearable bioelectrode 100 includes a plurality of conductive elastomer layers 20 in the in-plane direction of the flexible base material 10, it can be suitably used as an electrode for measuring an electrocardiogram waveform.

[0060] Examples of the subject include humans and animals other than humans.

[0061] The wearable bioelectrode 100 can be used as a simple and reusable dry sensor, rather than a wet sensor that requires application of a gel to the measurement part of the subject.

[0062] The flexible base material 10 has an electrode formation region where the conductive elastomer layer 20 is formed in a top view. In this electrode formation region, the flexible base material 10 and the conductive elastomer layer 20 are in close contact with each other when not stretched or stretched, and the mechanical strength of the entire wearable bioelectrode 100 can be increased.

[0063] Further, the flexible base material 10 may have an electrode non-formation region where the conductive elastomer layer 20 is not formed around the electric formation region. Mounting parts such as sewing threads and snap buttons for installation on clothes or the like can be attached to this electrode non-formation region. Alternatively, when the wearable bioelectrode 100 is wound around the body such as the wrist or ankle, the portions of the electrode non-formation region of the flexible base material 10 may be overlapped in the thickness direction and fixed to the body.

[0064] As shown in FIG. 1, an example of the flexible base material 10 has a band shape in which at least a part of it, for example, the main body 12, can be wound around the body. Such a wearable bioelectrode 100 has a structure suitable for a band-type bioelectrode that can be wound around a part of the body such as the wrist or ankle.

[0065] Further, the band-shaped flexible base material 10 in FIG. 3 may have a main body 12 and an extension portion 14 protruding 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, the deformation of the extension portion 14 is suppressed. Therefore, it is possible to suppress the occurrence of a connection failure in the external connection portion 30 attached to the extension portion 14.

[0066] The conductive elastomer layer 20 is configured in a sheet shape and has an exposed surface that directly contacts the body. In this specification, the sheet shape means that when the thickness of the conductive elastomer layer 20 is D (mm) and the area of one surface 22 in the top view of the conductive elastomer layer 20 is S (mm 2 ), S and D are, for example, 50 ≦ S / D, preferably 200 ≦ S / D, more preferably 400 ≦ S / D. The upper limit of S / D may be set according to the measurement site of the subject and is not particularly limited. For example, S / D ≦ 10 7 may also be acceptable.

[0067] The conductive elastomer layer 20 contacts the body when the wearable bioelectrode 100 is used and can well follow the contact surface along the surface shape of the body and the deformation of the body.

[0068] The outside of the wearable bioelectrode 100 may be configured such that the conductive elastomer layer 20 is connected, or may be configured such that a connection portion 26, which is a separate member electrically connected to the conductive elastomer layer 20, is connected. As shown in FIG. 3, this connection portion 26 may be configured to be electrically connected to the conductive elastomer layer 20 via the stretchable wiring 24.

[0069] The conductive elastomer layer 20, the stretchable wiring 24, and the connection portion 26 are made of the same or different conductive elastomers, and are preferably made of the same conductive elastomer.

[0070] Each part constituting the conductive elastomer layer 20 may be composed of a printed layer formed by a printing method using a conductive paste. In this case, each part including the conductive elastomer layer 20, the stretchable wiring 24, and the connection portion 26 may be configured seamlessly with each other.

[0071] The external connection portion 30 can send the bioelectrical signal detected through the conductive elastomer layer 20 to the outside, such as to an electronic component.

[0072] The wearable bioelectrode 100 in FIG. 3 includes an external connection portion 30. The external connection portion 30 is provided on the flexible base material 10 on the side opposite to the conductive elastomer layer 20. For example, the external connection portion 30 in FIG. 2 is formed on the other surface 13 of the flexible base material 10. Thereby, when the wearable bioelectrode 100 is used, it is possible to prevent the external connection portion 30 from coming into contact with the body together with the conductive elastomer layer 20, and to suppress interference with the detection of bioelectrical signals.

[0073] The external connection portion 30 is not particularly limited as long as it is configured to be electrically connected to the conductive elastomer layer 20, but is made of a conductive material such as a metal material or a conductive elastomer.

[0074] The shape of the external connection portion 30 is not particularly limited, but may have a connector that can be connected to an electronic component or a structure that facilitates the attachment of wiring.

[0075] An example of the external connection portion 30 may be composed of a metal snap button. The external connection part 30 in Fig. 4 is a male snap button and is fixed to the flexible substrate 10 using a mounting plate 32 and a mounting pin 34 which are metal fixtures. By the fixing method of sandwiching the flexible substrate 10 between the external connection part 30 and the mounting plate 32, displacement of the fixing position of the external connection part 30 can be suppressed. The mounting pin 34 contacts a part of the conductive elastomer layer 20, for example, the connection part 26, and electrical connection between the conductive elastomer layer 20 and the external connection part 30 can be achieved.

[0076] Also, a part of the surface or the entire surface of the mounting plate 32 in Fig. 4 is covered with an insulating protection layer 52. By the insulating protection layer 52, contact between the mounting plate 32 and the body can be prevented. The insulating protection layer 52 only needs to be composed of an insulating material, and may be composed of an insulating elastomer such as silicone rubber, for example.

[0077] The biosensor of this embodiment will be described.

[0078] The biosensor includes one wearable bioelectrode 100 or two or more wearable bioelectrodes 100 according to the application. The biosensor may be directly installed on the body, or may be installed on a body attachment member such as clothing.

[0079] The biosensor includes electronic components that can be electrically connected to the wearable bioelectrode 100 via the external connection part 30.

[0080] As the electronic components, known components can be used according to various applications. 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, a battery, etc. can be mentioned. One or two or more of these may be modularized on a circuit board. Thereby, the biosensor can be utilized as a wearable device. Also, other sensors such as an acceleration sensor, a temperature sensor, and a pressure sensor may be used in combination as the electronic components.

[0081] FIG. 5 is a diagram for explaining an example of the configuration of the biological sensor 200. The biological sensor 200 in FIG. 5 includes a wearable biological electrode 100, a connector 210, a cable 220, a sensor module 230, and a computer 240.

[0082] The connector 210 has a structure that can be electrically coupled to the external connection portion 30 of the wearable biological electrode 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. In the case of measuring an electrocardiogram waveform, an ECG sensor module can be used as the sensor module 230. The sensor module 230 has an electrical circuit that suppresses interference from an external RF source, line frequency, and electrical noise, and can suppress noise during measurement of a bioelectrical signal. The computer 240 can acquire a bioelectrical signal and generate and output waveforms of bioelectrical potentials such as surface electromyogram, electrocardiogram, skin potential, and electroencephalogram. The computer 240 may use a single-board computer composed of a printed circuit board including a CPU, peripheral components, an input / output interface, a connector, and the like.

[0083] The biological signal measurement system of the present embodiment will be described. The biological signal measurement system of the present embodiment includes a biological sensor. The biological signal measurement system can be a system (measurement device) that displays, analyzes, or stores data received from the biological sensor.

[0084] A modified example of the wearable biological electrode 100 will be described.

[0085] As shown in FIG. 1, the wearable biological electrode 100 may include a protective layer 50 between the flexible base material 10 and the external connection portion 30. Thereby, the mechanical strength can be increased, and damage to the conductive elastomer layer 20 can be suppressed when an external terminal is connected to the external connection portion 30 or the like.

[0086] The protective layer 50 may be formed wider than the external connection portion 30 when viewed from the other surface 13 side, or may be formed along the shape of the extension portion 14 of the flexible base material 10. Thereby, the mechanical strength in the extension portion 14 can be enhanced.

[0087] The protective layer 50 only needs to be made of a stretchable material. For example, it may be made of an insulating elastomer such as silicone rubber or the same material as the flexible base material 10. Thereby, the adhesion between the flexible base material 10 and the protective layer 50 can be enhanced.

[0088] The flexible base material 10 may be composed of a single layer or may be composed of a plurality of layers laminated together. The wearable bioelectrode 100 may have a multilayer wiring structure in which the flexible base material 10 and the conductive elastomer layer 20 are alternately laminated.

[0089] The shape of the flexible base material 10 in a top view is not particularly limited and can be appropriately deformed according to the application.

[0090] The flexible base material 10 may have one conductive elastomer layer 20 on the same surface 11, or may independently have two or more conductive elastomer layers 20.

[0091] The shape of the conductive elastomer layer 20 or the conductive elastomer layer 20 in a top view is not particularly limited and can be appropriately deformed according to the application. Examples include a square shape, a circular shape, an elliptical shape, and other polygonal shapes. Thereby, a certain contact area with the body can be ensured and the measurement stability can be enhanced.

[0092] The corners of the conductive elastomer layer 20 or the conductive elastomer layer 20 in a top view may have rounded corners. Thereby, local stress is generated at the corners during use, and damage to the conductive elastomer layer 20 can be suppressed.

[0093] The external connection portion 30 may be composed of one member, or may be composed of assembling a plurality of members. The external connection part 30 is installed on the flexible base material 10 by a mechanical method, but it may also be installed by a chemical method using an adhesive or the like.

[0094] As the snap button used for the external connection part 30, either a male snap button or a female snap button may be used. The external connection part 30 is fixed to the flexible base material 10, but it may also be detachably attached.

[0095] Hereinafter, the material of the conductive elastomer layer 20 will be described.

[0096] In an example of the flexible sheet electrode 1 of the present embodiment, the conductive elastomer layer 20 is composed of a conductive elastomer. Also, the insulating elastomer layer 60 is composed of an insulating elastomer. This insulating elastomer and conductive elastomer may be configured to contain the same elastomer material.

[0097] As the insulating elastomer, for example, silicone rubber, urethane rubber, fluororubber, nitrile rubber, acrylic rubber, styrene rubber, chloroprene rubber, ethylene propylene rubber, etc. can be used. Among these, the elastomer contains 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 the elastomer material alone, or may be configured to contain the elastomer material and a non-conductive filler. An example of the insulating elastomer contains silicone rubber, preferably contains silicone rubber and a non-conductive filler. Silicone rubber is chemically stable and has excellent mechanical strength among elastomers. Among these, from the viewpoint of hygiene, it is preferable to use silicone rubber with high biocompatibility as the elastomer material.

[0098] Conductive elastomers can be made of, for example, silicone rubber, urethane rubber, fluororubber, nitrile rubber, acrylic rubber, styrene rubber, chloroprene rubber, ethylene propylene rubber, etc. Among these, the elastomer contains 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. This can enhance the stretchability and conductivity of the conductive elastomer.

[0099] At least one, preferably both, of the insulating elastomer and the conductive elastomer may contain a non-conductive filler. As the non-conductive filler, known materials can be used. For example, silica particles, silicone rubber particles, talc, etc. may be used. Among these, it may contain silica particles.

[0100] The conductive filler may contain one or more selected from the group consisting of, for example, powdery or fibrous metal-based fillers, carbon-based fillers, metal oxide fillers, and metal-plated fillers. Among these, a metal-based filler such as silver powder may be used as the conductive filler.

[0101] In addition to the conductive filler, the conductive elastomer may further contain a non-conductive filler. This can enhance the mechanical properties of the conductive elastomer.

[0102] In a specific example, the conductive elastomer layer 20 may contain silver powder as the conductive filler, and preferably may contain flaky silver powder. This can improve conductivity, and further stretchable conductivity. Also, the conductive elastomer layer 20 may contain silver powder and silica particles as the non-conductive filler. This can improve the stretch durability of the conductive elastomer layer 20.

[0103] At least two or all of the conductive elastomer of the conductive elastomer layer 20, the insulating elastomer of the flexible substrate 10, and the insulating elastomers of the protective layer 50 and the insulating protective layer 52 may be configured to contain the same elastomer material.

[0104] In this specification, containing the same elastomer material means that each contains at least one or more of the same types of elastomer materials among the types of thermosetting elastomers exemplified above. Further, when containing the same silicone rubber, this silicone rubber may be composed of a cured product of a silicone rubber-based curable composition containing vinyl group-containing organopolysiloxane.

[0105] The insulating elastomer may be composed of a cured product of a silicone rubber-based curable composition containing vinyl group-containing organopolysiloxane. Further, the conductive elastomer may be composed of a conductive filler and a cured product of a silicone rubber-based curable composition containing vinyl group-containing organopolysiloxane.

[0106] Hereinafter, the components in the silicone rubber-based curable composition will be described in detail.

[0107] In this specification, containing the same silicone rubber means that the silicone rubber-based curable composition contains at least the same kind of vinyl group-containing linear organopolysiloxane, and further, may contain one or more selected from the group consisting of the same kind of crosslinking agent, the same kind of non-conductive filler, the same kind of silane coupling agent, and the same kind of catalyst.

[0108] The same kind of vinyl group-containing linear organopolysiloxane means that it contains at least the same vinyl group as the functional group, and it only needs to have a linear shape, and the amount of vinyl group, molecular weight distribution, or the added amount in the molecule may be different.

[0109] The same crosslinking agent only needs to have at least a common structure such as a linear structure or a branched structure, and may contain a molecular weight distribution or different functional groups in the molecule, and the addition amount thereof may also be different.

[0110] The same non-conductive filler only needs to have at least a common constituent material, and the particle diameter, specific surface area, surface treatment agent, or the addition amount thereof may be different.

[0111] The same silane coupling agent only needs to have at least a common functional group, and other functional groups or the addition amount in the molecule may be different.

[0112] The same catalyst only needs to have at least a common constituent material, and different compositions may be contained in the catalyst, and the addition amount thereof may also be different.

[0113] The silicone rubber-based curable composition constituting the same silicone rubber may further contain one or more selected from the group consisting of different types of vinyl group-containing linear organopolysiloxane, crosslinking agent, non-conductive filler, silane coupling agent, and catalyst.

[0114] The silicone rubber-based curable composition of the present embodiment can contain a vinyl group-containing organopolysiloxane (A). The vinyl group-containing organopolysiloxane (A) is a polymer that is the main component of the silicone rubber-based curable composition of the present embodiment.

[0115] The above vinyl group-containing organopolysiloxane (A) can contain a vinyl group-containing linear organopolysiloxane (A1) having a linear structure.

[0116] The above vinyl group-containing linear organopolysiloxane (A1) has a linear structure and contains a vinyl group, and such a vinyl group becomes a crosslinking point during curing.

[0117] The vinyl group content of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but for example, it preferably has two or more vinyl groups in the molecule and is 15 mol% or less. Thereby, the amount of vinyl groups in the vinyl group-containing linear organopolysiloxane (A1) is optimized, and the formation of a network with each of the components described later can be surely carried out.

[0118] In this specification, "~" represents including the upper limit value and the lower limit value unless otherwise specified.

[0119] In this specification, the vinyl group content means the mol% of vinyl group-containing siloxane units when the total units constituting the vinyl group-containing linear organopolysiloxane (A1) are 100 mol%. However, it is considered that there is one vinyl group for one vinyl group-containing siloxane unit.

[0120] Further, the degree of polymerization of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but for example, it is preferably in the range of about 1000 to 10000, more preferably about 2000 to 5000. The degree of polymerization can be determined, for example, as the number average degree of polymerization (or number average molecular weight) in terms of polystyrene in GPC (gel permeation chromatography) using chloroform as the developing solvent.

[0121] Furthermore, the specific gravity of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but it is preferably in the range of about 0.9 to 1.1.

[0122] By using the vinyl group-containing linear organopolysiloxane (A1) having a degree of polymerization and a specific gravity within the above ranges, the heat resistance, flame retardancy, chemical stability, etc. of the resulting silicone rubber can be improved.

[0123] As the vinyl group-containing linear organopolysiloxane (A1), those having a structure represented by the following formula (1) are particularly preferred.

[0124] [Chemical formula]

[0125] In formula (1), R 1 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group having 1 to 10 carbon atoms, or a hydrocarbon group combining these. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, etc. Among them, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, a butenyl group, etc. Among them, a vinyl group is preferable. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group, etc.

[0126] Also, R 2 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group having 1 to 10 carbon atoms, or a hydrocarbon group combining these. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, etc. Among them, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, a butenyl group. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

[0127] Also, R 3 is a substituted or unsubstituted alkyl group, aryl group having 1 to 8 carbon atoms, or a hydrocarbon group combining these. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, a propyl group, etc. Among them, a methyl group is preferable. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group.

[0128] Furthermore, examples of the substituents of R 1 and R 2 in formula (1) include a methyl group, a vinyl group, etc. Examples of the substituents of R 3 include a methyl group, etc.

[0129] Note that in formula (1), a plurality of R 1They are independent of each other and may be different from each other or the same. Further, R 2 and R 3 are the same.

[0130] Furthermore, m and n are the number of repeating units constituting the vinyl group-containing linear organopolysiloxane (A1) represented by the formula (1). m is an integer from 0 to 2000, and n is an integer from 1000 to 10000. m is preferably from 0 to 1000, and n is preferably from 2000 to 5000.

[0131] In addition, specific structures of the vinyl group-containing linear organopolysiloxane (A1) represented by the formula (1) include, for example, those represented by the following formula (1-1).

[0132]

Chemical formula

[0133] In the 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.

[0134] The vinyl group-containing linear organopolysiloxane (A1) may contain a first vinyl group-containing linear organopolysiloxane (A1-1) having a vinyl group content of 2 or more vinyl groups in the molecule and 0.4 mol% or less. The amount of vinyl groups in the first vinyl group-containing linear organopolysiloxane (A1-1) may be 0.1 mol% or less.

[0135] In addition, the vinyl group-containing linear organopolysiloxane (A1) may contain the 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%.

[0136] As raw rubber, which is a raw material for silicone rubber, by combining a first vinyl group-containing linear organopolysiloxane (A1-1) and a second vinyl group-containing linear organopolysiloxane (A1-2) with a high vinyl group content, the vinyl groups can be unevenly distributed, and in the crosslinked network of the silicone rubber, the density of the crosslinking density can be more effectively formed. As a result, the tear strength of the silicone rubber can be more effectively increased.

[0137] Specifically, as the vinyl group-containing linear organopolysiloxane (A1), for example, in the above formula (1-1), a first vinyl group-containing linear organopolysiloxane (A1-1) having two or more units in which R1 is a vinyl group and / or R2 is a vinyl group in the molecule and containing 0.4 mol% or less, 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 R2 is a vinyl group are preferably used.

[0138] Further, the first vinyl group-containing linear organopolysiloxane (A1-1) preferably has a vinyl group content of 0.01 to 0.2 mol%. Further, the second vinyl group-containing linear organopolysiloxane (A1-2) preferably has a vinyl group content of 0.8 to 12 mol%.

[0139] 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. 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.

[0140] In addition, for the first and second vinyl group-containing linear organopolysiloxanes (A1-1) and (A1-2), only one kind may be used respectively, or two or more kinds may be used in combination.

[0141] In addition, the vinyl group-containing organopolysiloxane (A) may contain a vinyl group-containing branched organopolysiloxane (A2) having a branched structure.

[0142] <<Organohydrogenpolysiloxane (B)>> The silicone rubber-based curable composition of the present 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 can contain either one or both of these.

[0143] The linear organohydrogenpolysiloxane (B1) has a linear structure and a structure in which hydrogen is directly bonded to Si (≡Si-H). In addition to the vinyl group of the vinyl group-containing organopolysiloxane (A), it undergoes a hydrosilylation reaction with the vinyl groups of the components incorporated in the silicone rubber-based curable composition and is a polymer that crosslinks these components.

[0144] The molecular weight of the linear organohydrogenpolysiloxane (B1) is not particularly limited. For example, the weight average molecular weight is preferably 20,000 or less, more preferably 1,000 or more and 10,000 or less.

[0145] The weight average molecular weight of the linear organohydrogenpolysiloxane (B1) can be measured, for example, by polystyrene conversion in GPC (gel permeation chromatography) using chloroform as the developing solvent.

[0146] In addition, the linear organohydrogenpolysiloxane (B1) preferably usually does not have a vinyl group. Thereby, it is possible to accurately prevent the crosslinking reaction from proceeding in the molecule of the linear organohydrogenpolysiloxane (B1).

[0147] As the linear organohydrogenpolysiloxane (B1) as described above, for example, those having a structure represented by the following formula (2) are preferably used.

[0148] [Chemical formula]

[0149] In formula (2), R 4 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, hydrocarbon group combining these, or 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, a propyl group, etc. Among them, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, a butenyl group, etc. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

[0150] Also, R 5 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, hydrocarbon group combining these, or 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, a propyl group. Among them, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, a butenyl group, etc. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

[0151] In addition, in formula (2), a plurality of R 4 are independent of each other, and may be different from each other or the same. The same applies to R 5 . However, among a plurality of R 4 and R 5 , at least two or more are hydride groups.

[0152] Also, R 6is a substituted or unsubstituted alkyl group, aryl group, or a hydrocarbon group combining these, having 1 to 8 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, a propyl group, etc., and among them, a methyl group is preferable. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group. A plurality of R 6 are independent of each other, and may be different from each other or may be the same.

[0153] In addition, examples of the substituent of R 4 , R 5 , R 6 in the formula (2) include a methyl group, a vinyl group, etc., and from the viewpoint of preventing the crosslinking reaction in the molecule, a methyl group is preferable.

[0154] Furthermore, m and n are the number of repeating units constituting the linear organohydrogenpolysiloxane (B1) represented by the formula (2), 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.

[0155] In addition, the linear organohydrogenpolysiloxane (B1) may be used alone as one kind, or two or more kinds may be used in combination.

[0156] Since the branched organohydrogenpolysiloxane (B2) has a branched structure, it forms a region with a high crosslinking density and is a component that greatly contributes to the formation of the dense structure of the crosslinking density in the silicone rubber system. Also, similar to the above linear organohydrogenpolysiloxane (B1), it has a structure in which hydrogen is directly bonded to Si (≡Si-H), and in addition to the vinyl group of the vinyl group-containing organopolysiloxane (A), it undergoes a hydrosilylation reaction with the vinyl groups of the components blended in the silicone rubber-based curable composition and is a polymer that crosslinks these components.

[0157] Also, the specific gravity of the branched organohydrogenpolysiloxane (B2) is in the range of 0.9 to 0.95.

[0158] Furthermore, the branched organohydrogenpolysiloxane (B2) preferably does not usually have a vinyl group. This makes it possible to accurately prevent the cross-linking reaction from proceeding within the molecule of the branched organohydrogenpolysiloxane (B2).

[0159] Moreover, as the branched organohydrogenpolysiloxane (B2), those represented by the following average composition formula (c) are preferred.

[0160] 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 in the range of 1 to 3, m is the number of H a (R 7 ) 3-a SiO 1 / 2 units, and n is the number of SiO 4 / 2 units)

[0161] In formula (c), R 7 is a monovalent organic group, preferably a substituted or unsubstituted alkyl group, aryl group, or hydrocarbon group combining these, having 1 to 10 carbon atoms. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, etc., and among them, a methyl group is preferred. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

[0162] In formula (c), a is the number of hydride groups (hydrogen atoms directly bonded to Si), an integer in the range of 1 to 3, preferably 1.

[0163] Moreover, in formula (c), m is the number of H a (R 7 ) 3-a SiO 1 / 2 units, and n is the number of SiO 4 / 2 units.

[0164] The branched organohydrogenpolysiloxane (B2) has a branched structure. The linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) differ in that the structure is linear or branched, and the number of alkyl groups R bonded to Si (R / Si) when 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).

[0165] In addition, since the branched organohydrogenpolysiloxane (B2) has a branched structure, for example, when heated at a heating rate of 10 °C / min up to 1000 °C in a nitrogen atmosphere, the residue amount is 5% or more. On the other hand, since the linear organohydrogenpolysiloxane (B1) is linear, the residue amount after heating under the above conditions is almost zero.

[0166] Moreover, specific examples of the branched organohydrogenpolysiloxane (B2) include those having a structure represented by the following formula (3).

[0167]

Chemical formula

[0168] In formula (3), R 7 is a substituted or unsubstituted alkyl group, aryl group, or hydrocarbon group combining these, or a hydrogen atom, having 1 to 8 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, a propyl group, etc., and among them, a methyl group is preferable. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group. Examples of the substituent of R 7 include a methyl group, etc.

[0169] In addition, in formula (3), a plurality of R 7 are independent of each other and may be different from each other or the same.

[0170] In addition, in Formula (3), “-O-Si≡” represents that Si has a branched structure that spreads three-dimensionally.

[0171] Note that as the branched organohydrogenpolysiloxane (B2), only one kind may be used alone, or two or more kinds may be used in combination.

[0172] In addition, in the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2), the amount of hydrogen atoms (hydride groups) directly bonded to Si 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, and more preferably 1 to 3.5 moles, per 1 mole of vinyl groups in the vinyl group-containing linear organopolysiloxane (A1). Thereby, a crosslinked network can be surely formed between the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2), and the vinyl group-containing linear organopolysiloxane (A1).

[0173] <<Silica particles (C)>> The silicone rubber-based curable composition of the present embodiment may contain silica particles (C) as a non-conductive filler, if necessary.

[0174] The silica particles (C) are not particularly limited, and for example, fumed silica, calcined silica, precipitated silica, etc. are used. These may be used alone or in combination of two or more kinds.

[0175] The silica particles (C) preferably have a specific surface area by the BET method of, for example, 50 to 400 m 2 / g, and more preferably 100 to 400 m 2It is more preferably / g. Further, the average primary particle diameter of the silica particles (C) is preferably, for example, 1 to 100 nm, and more preferably about 5 to 20 nm.

[0176] By using silica particles (C) within such a range of specific surface area and average particle diameter, it is possible to improve the hardness and mechanical strength of the formed silicone rubber, particularly the tensile strength.

[0177] <<Silane coupling agent (D)>> The silicone rubber-based curable composition of the present embodiment may contain a silane coupling agent (D). The silane coupling agent (D) can have a hydrolyzable group. The hydrolyzable group is hydrolyzed by water to become a hydroxyl group, and this hydroxyl group can react with the hydroxyl groups on the surface of the silica particles (C) by dehydration condensation reaction to modify the surface of the silica particles (C).

[0178] In addition, the silane coupling agent (D) can include a silane coupling agent having a hydrophobic group. As a result, this hydrophobic group is imparted to the surface of the silica particles (C), so that in the silicone rubber-based curable composition and thus in the silicone rubber, the cohesive force of the silica particles (C) is reduced (less aggregation due to hydrogen bonding by silanol groups), and as a result, it is presumed that the dispersibility of the silica particles in the silicone rubber-based curable composition is improved. Thereby, the interface between the silica particles and the rubber matrix increases, and the reinforcing effect of the silica particles increases. Furthermore, when the matrix of the rubber is deformed, it is presumed that the slipperiness of the silica particles within the matrix is improved. And due to the improvement of the dispersibility and slipperiness of the silica particles (C), the mechanical strength of the silicone rubber by the silica particles (C) (for example, tensile strength, tear strength, etc.) is improved.

[0179] Furthermore, the silane coupling agent (D) can include a silane coupling agent having a vinyl group. As a result, a vinyl group is introduced onto the surface of the silica particles (C). Therefore, when the silicone rubber-based curable composition cures, that is, when the vinyl group of the vinyl group-containing organopolysiloxane (A) and the hydride group of the organohydrogenpolysiloxane (B) undergo a hydrosilylation reaction to form a network (crosslinked structure) therefrom, the vinyl group of the silica particles (C) also participates in the hydrosilylation reaction with the hydride group of the organohydrogenpolysiloxane (B), so that the silica particles (C) are also incorporated into the network. Thereby, it is possible to reduce the hardness and increase the modulus of the formed silicone rubber.

[0180] 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.

[0181] Examples of the silane coupling agent (D) include those represented by the following formula (4).

[0182] Y n -Si-(X) 4-n ···(4) In the above formula (4), n represents an integer of 1 to 3. Y represents any of a functional group having a hydrophobic group, a hydrophilic group, or a vinyl group. When n is 1, it is a hydrophobic group, and when n is 2 or 3, at least one of them is a hydrophobic group. X represents a hydrolyzable group.

[0183] The hydrophobic group is an alkyl group having 1 to 6 carbon atoms, an aryl group, or a hydrocarbon group combining these, and examples thereof include a methyl group, an ethyl group, a propyl group, a phenyl group, etc. Among them, in particular, a methyl group is preferable.

[0184] In addition, examples of the hydrophilic group include a hydroxyl group, a sulfonic acid group, a carboxyl group, a carbonyl group, etc. Among them, a hydroxyl group is particularly preferable. The hydrophilic group may be included as a functional group, but it is preferably not included from the viewpoint of imparting hydrophobicity to the silane coupling agent (D).

[0185] Furthermore, examples of the hydrolyzable group include an alkoxy group such as a methoxy group or an ethoxy group, a chloro group, a silazane group, etc. Among them, a silazane group is preferable because of its high reactivity with the silica particles (C). Note that those having a silazane group as the hydrolyzable group will have two structures of (Y n -Si-) in the above formula (4) due to the structural characteristics thereof.

[0186] Specific examples of the silane coupling agent (D) represented by the above formula (4) include, for example, as those having a hydrophobic group as a functional group, alkoxysilanes such as methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, decyltrimethoxysilane; chlorosilanes such as methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane; hexamethyldisilazane. As those having a vinyl group as a functional group, alkoxysilanes such as methacryloxypropyltriethoxysilane, methacryloxypropyltrimethoxysilane, methacryloxypropylmethyldiethoxysilane, methacryloxypropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane; chlorosilanes such as vinyltrichlorosilane, vinylmethyldichlorosilane; divinyldimethyltetrasilazane. Among them, considering the above description, particularly, hexamethyldisilazane is preferable as those having a hydrophobic group, and divinyldimethyltetrasilazane is preferable as those having a vinyl group.

[0187] 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 with respect to 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A). Also, 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 with respect to 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 be not less than the above lower limit, when using silica particles (C), it can contribute to the improvement of the mechanical strength of the entire silicone rubber. Also, by setting the content of the silane coupling agent (D) to be not more than the above upper limit, the silicone rubber can have appropriate mechanical properties.

[0188] <<Platinum or platinum compound (E)>> The silicone rubber-based curable composition of this embodiment may contain platinum or a platinum compound (E). Platinum or a platinum compound (E) is a catalyst component that acts as a catalyst during curing. The addition amount of platinum or a platinum compound (E) is a catalytic amount.

[0189] As the platinum or platinum compound (E), known ones can be used. For example, platinum black, platinum supported on silica, carbon black, etc., chloroplatinic acid or an alcohol solution of chloroplatinic acid, a complex salt of chloroplatinic acid and an olefin, a complex salt of chloroplatinic acid and a vinylsiloxane, etc. can be mentioned.

[0190] Note that only one kind of platinum or platinum compound (E) may be used alone, or two or more kinds may be used in combination.

[0191] <<Water (F)>> Also, in the silicone rubber-based curable composition of this embodiment, in addition to the above components (A) to (E), water (F) may be contained.

[0192] Water (F) functions as a dispersion medium for dispersing each component contained in the silicone rubber-based curable composition, and is a component that contributes to the reaction between the silica particles (C) and the silane coupling agent (D). Therefore, in the silicone rubber, the silica particles (C) and the silane coupling agent (D) can be more surely connected to each other, and uniform characteristics can be exhibited as a whole.

[0193] Furthermore, when water (F) is contained, its content can be set as appropriate. Specifically, for example, it is preferably in the range of 10 to 100 parts by weight, and more preferably in the range of 30 to 70 parts by weight, based on 100 parts by weight of the silane coupling agent (D). Thereby, the reaction between the silane coupling agent (D) and the silica particles (C) can proceed more surely.

[0194] (Other components) Furthermore, the silicone rubber-based curable composition of the present embodiment can further contain other components in addition to the components (A) to (F) above. Examples of such other components include 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, mica, reaction inhibitors, dispersants, pigments, dyes, antistatic agents, antioxidants, flame retardants, thermal conductivity improvers, and other additives.

[0195] In the silicone rubber-based curable composition, the content ratio of each component is not particularly limited, but is set as follows, for example.

[0196] In this embodiment, the upper limit of the content of the silica particles (C) may be, for example, 60 parts by weight or less, preferably 50 parts by weight or less, more preferably 40 parts by weight or less, based on 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A). Thereby, the balance of mechanical strengths such as hardness and tensile strength can be achieved. Further, the lower limit of the content of the silica particles (C) is not particularly limited, but may be, for example, 10 parts by weight or more, based on 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A).

[0197] The silane coupling agent (D) is preferably contained in a proportion of, for example, 5 parts by weight or more and 100 parts by weight or less, more preferably 5 parts by weight or more and 40 parts by weight or less, based on 100 parts by weight of the vinyl group-containing organopolysiloxane (A). Thereby, the dispersibility of the silica particles (C) in the silicone rubber-based curable composition can be surely improved.

[0198] The content of the organohydrogenpolysiloxane (B) is preferably, for example, in a proportion of 0.5 parts by weight or more and 20 parts by weight or less, more preferably 0.8 parts by weight or more and 15 parts by weight or less, based on 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A), the silica particles (C), and the silane coupling agent (D). When the content of (B) is within the above range, a more effective curing reaction may be possible.

[0199] The content of platinum or platinum compound (E) means a catalytic amount and can be set as appropriate. Specifically, based on the total amount of vinyl group-containing organopolysiloxane (A), silica particles (C), and silane coupling agent (D), the platinum group metal in this component is in an amount of 0.01 to 1000 ppm by weight, preferably in an amount of 0.1 to 500 ppm by weight. By setting the content of platinum or platinum compound (E) to be not less than the above lower limit value, the resulting silicone rubber composition can be sufficiently cured. By setting the content of platinum or platinum compound (E) to be not more than the above upper limit value, the curing rate of the resulting silicone rubber composition can be improved.

[0200] Furthermore, when water (F) is contained, its content can be set as appropriate. 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, based on 100 parts by weight of the silane coupling agent (D). Thereby, the reaction between the silane coupling agent (D) and the silica particles (C) can proceed more reliably.

[0201] In this embodiment, for example, by appropriately selecting the types and blending amounts of the respective components contained in the silicone rubber-based curable composition, the preparation method of the silicone rubber-based curable composition, etc., it is possible to control the above-mentioned hardness, tensile strength, elongation at break, and tear strength. Among these, for example, appropriately controlling the type and blending ratio of the resin constituting the silicone rubber, the crosslinking density and crosslinking structure of the resin, improving the blending ratio of the inorganic filler and the bonding 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, appropriately adjusting the content of the silica particles (C) and the content of the silane coupling agent, etc. can be cited as elements for setting the above-mentioned hardness, tensile strength, elongation at break, and tear strength within a desired numerical range.

[0202] <Method for manufacturing silicone rubber> Next, the method for manufacturing the silicone rubber of this embodiment will be described. As a method for producing the silicone rubber of this embodiment, a silicone rubber-based curable composition can be prepared and the silicone rubber can be obtained by curing this silicone rubber-based curable composition. This will be described in detail below.

[0203] First, each component of the silicone rubber-based curable composition is uniformly mixed by an arbitrary kneading device to prepare a silicone rubber-based curable composition.

[0204] [1] For example, a predetermined amount of a vinyl group-containing organopolysiloxane (A), silica particles (C), and a silane coupling agent (D) are weighed, and then kneaded by an arbitrary kneading device to obtain a kneaded product containing these components (A), (C), and (D).

[0205] Note that it is preferable to obtain this kneaded product by first kneading the vinyl group-containing organopolysiloxane (A) and the silane coupling agent (D), and then kneading (mixing) the silica particles (C). Thereby, the dispersibility of the silica particles (C) in the vinyl group-containing organopolysiloxane (A) is further improved.

[0206] Also, when obtaining this kneaded product, water (F) may be added to the kneaded product of each component (A), (C), and (D) as necessary. Thereby, the reaction between the silane coupling agent (D) and the silica particles (C) can proceed more reliably.

[0207] Furthermore, it is preferable that the kneading of each component (A), (C), and (D) undergoes a first step of heating at a first temperature and a second step of heating at a second temperature. Thereby, in the first step, the surface of the silica particles (C) can be surface-treated with the coupling agent (D), and in the second step, the by-products generated by the reaction between the silica particles (C) and the coupling agent (D) can be surely removed from the kneaded product. Thereafter, if necessary, component (A) may be added to the obtained kneaded product and further kneaded. Thereby, the compatibility of the components of the kneaded product can be improved.

[0208] The first temperature is preferably about 40 to 120 °C, more preferably about 60 to 90 °C. The second temperature is preferably about 130 to 210 °C, more preferably about 160 to 180 °C.

[0209] In addition, the atmosphere in the first step is preferably an inert atmosphere such as under a nitrogen atmosphere, and the atmosphere in the second step is preferably under a reduced pressure atmosphere.

[0210] Furthermore, the time of the first step is preferably about 0.3 to 1.5 hours, more preferably about 0.5 to 1.2 hours. The time of the second step is preferably about 0.7 to 3.0 hours, more preferably about 1.0 to 2.0 hours.

[0211] By setting the first step and the second step under the above conditions, the above effects can be obtained more significantly.

[0212] [2] Next, a predetermined amount of organohydrogenpolysiloxane (B) and platinum or a platinum compound (E) are weighed, and then, using an arbitrary kneading device, each component (B), (E) is kneaded into the kneaded product prepared in the above step [1] to obtain a silicone rubber-based curable composition. The obtained silicone rubber-based curable composition may be a paste containing a solvent.

[0213] When kneading each of these components (B) and (E), it is preferable to knead the kneaded product prepared in the above step [1] and organohydrogenpolysiloxane (B) in advance, and knead the kneaded product prepared in the above step [1] and platinum or a platinum compound (E), and then knead each kneaded product. Thereby, each component (A) to (E) can be surely dispersed in the silicone rubber-based curable composition without promoting the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B).

[0214] When kneading each of the components (B) and (E), the temperature as the roll setting temperature is preferably about 10 to 70°C, more preferably about 25 to 30°C.

[0215] Furthermore, the kneading time is preferably about 5 minutes to 1 hour, more preferably about 10 to 40 minutes.

[0216] In the above step [1] and the above step [2], by setting the temperature within the above range, the progress of the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) can be more accurately prevented or suppressed. Also, in the above step [1] and the above step [2], by setting the kneading time within the above range, each of the components (A) to (E) can be more reliably dispersed in the silicone rubber-based curable composition.

[0217] The kneading apparatus used in each of the steps [1] and [2] is not particularly limited, and for example, a kneader, two-roll mill, Banbury mixer (continuous kneader), pressure kneader, etc. can be used.

[0218] Also, in this step [2], a reaction inhibitor such as 1-ethynylcyclohexanol may be added to the kneaded product. Thereby, even if the temperature of the kneaded product is set to a relatively high temperature, the progress of the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) can be more accurately prevented or suppressed.

[0219] [3] Next, a silicone rubber is formed by curing the silicone rubber-based curable composition.

[0220] In this embodiment, the curing step of the silicone rubber-based curable resin composition is performed, for example, by heating at 100 to 250°C for 1 to 30 minutes (primary curing) and then post-baking at 200°C for 1 to 4 hours (secondary curing).

[0221] By going through the steps as described above, a silicone rubber made of a cured product of a silicone rubber-based curable resin composition can be obtained.

[0222] Incidentally, [3] Next, an insulating paste can be obtained by dissolving the silicone rubber-based curable composition obtained in step [2] in a solvent. Also, [3] Next, a conductive paste can be obtained by dissolving the silicone rubber-based curable composition obtained in step [2] in a solvent and adding a conductive filler.

[0223] (Solvent) The conductive paste and the insulating paste contain a solvent. As the solvent, various known solvents can be used. For example, a high-boiling solvent can be included. These can be used alone or in combination of two or more.

[0224] The lower limit of the boiling point of the above high-boiling solvent is, for example, 100 °C or higher, preferably 130 °C or higher, more preferably 150 °C or higher. Thereby, the printing stability such as screen printing can be improved. On the other hand, the upper limit of the boiling point of the above high-boiling solvent is not particularly limited, but for example, it may be 300 °C or lower, 290 °C or lower, or 280 °C or lower. Thereby, an excessive heat history during wiring formation can be suppressed, so that damage to the substrate and the shape of the wiring formed with the conductive paste can be maintained well.

[0225] Also, as the solvent, it can be appropriately selected from the viewpoints of the solubility and boiling point of the silicone rubber-based curable resin composition. For example, it can contain an aliphatic hydrocarbon having 5 to 20 carbon atoms, preferably an aliphatic hydrocarbon having 8 to 18 carbon atoms, more preferably an aliphatic hydrocarbon having 10 to 15 carbon atoms.

[0226] Examples of the solvent include, for example, aliphatic hydrocarbons such as pentane, hexane, cyclohexane, heptane, methylcyclohexane, ethylcyclohexane, octane, decane, dodecane, tetradecane; aromatic hydrocarbons such as benzene, toluene, ethylbenzene, xylene, mesitylene, trifluoromethylbenzene, benzotrifluoride; ethers such as diethyl ether, diisopropyl ether, dibutyl ether, cyclopentyl methyl ether, cyclopentyl ethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol monobutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol methyl-n-propyl ether, 1,4-dioxane, 1,3-dioxane, tetrahydrofuran; haloalkanes such as dichloromethane, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2-trichloroethane; carboxylic acid amides such as N,N-dimethylformamide, N,N-dimethylacetamide; sulfoxides such as dimethyl sulfoxide, diethyl sulfoxide; esters such as diethyl carbonate, etc. These can be used alone or in combination of two or more. The solvent used here may be appropriately selected from solvents capable of uniformly dissolving or dispersing the components in the above conductive paste.

[0227] When the above solvent has an upper limit value of the polar term (δ p ) of the Hansen solubility parameter, for example, 10 MPa 1 / 2 or less, preferably 7 MPa 1 / 2 or less, and more preferably 5.5 MPa 1 / 2 or less, it can contain a first solvent. Thereby, the dispersibility and solubility of the silicone rubber-based curable resin composition in the paste can be made good. The lower limit value of the polar term (δ p ) of this first solvent is not particularly limited, but for example, 0 Pa 1 / 2 or more may be sufficient.

[0228] The upper limit of the hydrogen bonding term (δ h ) of the Hansen solubility parameter in the above-mentioned first solvent is, for example, 20 MPa 1 / 2 or less, preferably 10 MPa 1 / 2 or less, more preferably 7 MPa 1 / 2 or less. Thereby, in the paste, the dispersibility and solubility of the silicone rubber-based curable resin composition can be made good. The lower limit of the hydrogen bonding term (δ h ) of this first solvent is not particularly limited, but may be, for example, 0 Pa 1 / 2 or more.

[0229] The Hansen solubility parameter (HSP) is an index representing the solubility of how well one substance dissolves in another substance. HSP represents solubility as a three-dimensional vector. This three-dimensional vector can typically be represented by a dispersion term (δ d ), a polar term (δ p ), and a hydrogen bonding term (δ h ). And those with similar vectors can be judged to have high solubility. It is possible to judge the similarity of the vectors by the distance of the Hansen solubility parameter (HSP distance).

[0230] The Hansen solubility parameter (HSP value) used in this specification can be calculated using software called HSPiP (Hansen Solubility Parameters in Practice). Here, the computer software HSPiP developed by Hansen and Abbott includes a function for calculating the HSP distance and a database describing the Hansen parameters of various resins and solvents or non-solvents. Examine the solubility of each resin in pure solvents and mixed solvents of good solvents and poor solvents, input the results into the HSPiP software, and calculate D: dispersion term, P: polar term, H: hydrogen bonding term, and R0: dissolution sphere radius.

[0231] As the solvent of the present embodiment, for example, those with a small difference in HSP distance, polarity term, or hydrogen bond term between the elastomer or the structural unit constituting the elastomer and the solvent can be selected.

[0232] The lower limit of the viscosity of the conductive paste and / or insulating paste 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. Thereby, the film-forming property can be improved. Also, the shape retention property can be enhanced even during thick film formation. 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. Thereby, the printability of the paste can be improved.

[0233] At room temperature of 25°C, let the viscosity measured at a shear rate of 1 [1 / s] be η1, the viscosity measured at a shear rate of 5 [1 / s] be η5, and the thixotropy index be the viscosity ratio (η1 / η5). At this time, 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. Thereby, the shape of the wiring obtained by the printing method can 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. Thereby, the ease of printing the paste can be improved.

[0234] 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 in 100% by mass of the insulating paste. Also, 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 in 100% by mass of the insulating paste.

[0235] (Conductive filler) As the conductive filler, a known conductive material may be used, or metal powder (G) may be used. The metal constituting the metal powder (G) is not particularly limited. For example, it can include at least one of copper, silver, gold, nickel, tin, lead, zinc, bismuth, antimony, or metal powder alloyed thereof, or two or more of these. Among these, as the metal powder (G), it is preferable to contain silver or copper, that is, to contain silver powder or copper powder, in view of high conductivity and easy availability. Note that these metal powders (G) coated with other metals can also be used.

[0236] In this embodiment, the shape of the metal powder (G) is not limited, and conventionally used ones such as dendritic, spherical, and flaky shapes can be used. Among these, flaky metal powder (G) may be used.

[0237] Also, the particle size of the metal powder (G) is not limited. For example, the average particle size D 50 is preferably 0.001 μm or more, more preferably 0.01 μm or more, and even more preferably 0.1 μm or more. The particle size of the metal powder (G) is, for example, the average particle size D 50 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 it within such a range, it is possible to exhibit appropriate conductivity as a silicone rubber. The particle size of the metal powder (G) can be defined, for example, as the average value of 200 arbitrarily selected metal powders after observing a conductive paste or a silicone rubber molded using the conductive paste with a transmission electron microscope or the like and performing image analysis.

[0238] The content of the conductive filler in the conductive paste is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more with respect to the whole conductive paste. Also, the content of the conductive filler in the conductive paste is preferably 85% by mass or less, more preferably 75% by mass or less, and even more preferably 65% by mass or less with respect to the whole conductive paste. By setting the content of the conductive filler to be not less than the above lower limit value, the silicone rubber can have appropriate conductive properties. Also, by setting the content of the conductive filler to be not more than the above upper limit value, the silicone rubber can have appropriate flexibility.

[0239] 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 in 100% by mass of the conductive paste. Also, 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 in 100% by mass of the conductive paste. By setting the content of the silicone rubber-based curable composition to be not less than the above lower limit value, the silicone rubber can have appropriate flexibility. Also, by setting the content of the silicone rubber-based curable composition to be not more than the above upper limit value, it is possible to improve the mechanical strength of the silicone rubber.

[0240] 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, 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. Thereby, the mechanical strength of the silicone rubber can be improved. On the other hand, the upper limit of the content of the silica particles (C) in the conductive paste is, for example, 20% by mass or less, preferably 15% by mass or less, 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. Thereby, the balance between the stretch electrical characteristics and the mechanical strength in the silicone rubber can be achieved.

[0241] The lower limit of the content of the conductive filler in the conductive cured product obtained by curing the conductive paste constituting the conductive elastomer layer 20 is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more in 100% by mass of the conductive cured product. Thereby, the stretch electrical characteristics can be enhanced. On the other hand, the upper limit of the content of the conductive filler in the conductive cured product is, for example, 90% by mass or less, preferably 88% by mass or less, more preferably 85% by mass or less in 100% by mass of the conductive elastomer layer 20. Thereby, the decrease in rubber characteristics such as stretchability can be suppressed.

[0242] The lower limit of the content of the silica particles (C) in the conductive cured product obtained by curing the conductive paste constituting the conductive elastomer layer 20 can be, for example, 1% by mass or more, preferably 3% by mass or more, 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. Thereby, the mechanical strength of the silicone rubber can be improved. On the other hand, the upper limit of the content of the silica particles (C) in the conductive cured product is, for example, 20% by mass or less, preferably 15% by mass or less, 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. Thereby, the balance between the stretch electrical characteristics and the mechanical strength in the silicone rubber can be achieved.

[0243] The embodiments of the present invention have been described above, but these are merely examples of the present invention, and various configurations other than those described above can be adopted. Further, the present invention is not limited to the above-described embodiments, and modifications, improvements, etc. within the scope capable of achieving the object of the present invention are included in the present invention. Examples of reference configurations are described below. 1. A flexible substrate, and a conductive elastomer layer provided on the flexible substrate, wherein the flexible sheet electrode comprises: Let the arithmetic mean height on the surface of the conductive elastomer layer at 20% elongation measured by a laser microscope with a laser light wavelength of 404 nm be Sa 20 and the maximum height be Sz. 20 When Sa 20 ≤ 19.5 μm and / or Sz 20 ≤ 200 μm are satisfied, A flexible sheet electrode. 2. The flexible sheet electrode according to 1., Let the arithmetic mean height on the surface of the conductive elastomer layer at no elongation measured by a laser microscope with a laser light wavelength of 404 nm be Sa 0 and the maximum height be Sz. 0 When 0 μm ≤ |Sa 20 - Sa 0 | ≤ 10 μm and / or 0 μm ≤ |Sz 20 - Sz 0 | ≤ 80 μm are satisfied, a flexible sheet electrode. 3. The flexible sheet electrode according to 1. or 2., After repeating the washing process 20 times according to the following procedures (1) to (4), let the arithmetic mean height on the surface of the conductive elastomer layer at no elongation measured by a laser microscope with a laser light wavelength of 404 nm be Sa W0 and the maximum height be Sz. W0 When Sa W0 ≤ 16.0 μm and / or Sz W0 ≤ 250 μm are satisfied, a flexible sheet electrode. (Procedure) 1. Stretch and contract the flexible sheet electrode 300 times by 50% in the longitudinal and transverse directions respectively. 2. Put a neutral detergent and water in a beaker, immerse the flexible sheet electrode treated in 1., and stir for 24 hours. 3. Put water in the beaker, immerse the flexible sheet electrode treated in 2., stir for 10 minutes, and rinse the detergent. 4. Dry in an oven at 90 °C for 30 minutes. 4. The flexible sheet electrode according to any one of 1. to 3., wherein the conductive elastomer layer contains a conductive filler and a non-conductive filler, a flexible sheet electrode. 5. The flexible sheet electrode according to 4., wherein the conductive filler contains one or more selected from the group consisting of a metal-based filler, a carbon-based filler, a metal oxide filler, and a metal plating filler, a flexible sheet electrode. 6. The flexible sheet electrode according to 4. or 5., wherein the conductive filler contains flaky silver powder, a flexible sheet electrode. 7. The flexible sheet electrode according to any one of 4. to 6., wherein the non-conductive filler contains silica particles, a flexible sheet electrode. 8. The flexible sheet electrode according to any one of 4 to 7, wherein the content of the conductive filler is 50% by mass or more and 90% by mass or less in the conductive elastomer layer, the flexible sheet electrode. 9. The flexible sheet electrode according to any one of 1 to 8, wherein the conductive elastomer layer contains one or more elastomer materials selected from the group consisting of silicone rubber, urethane rubber, and fluororubber, the flexible sheet electrode. 10. The flexible sheet electrode according to any one of 1 to 9, wherein in the conductive elastomer layer, when the surface resistance value at the time of no elongation is R1 and the surface resistance value when the surface is stretched by 20% in one of the in-plane directions is R2, R1 and R2 are configured to satisfy 1.0 ≦ R2 / R1 ≦ 7.0, the flexible sheet electrode. 11. The flexible sheet electrode according to any one of 1 to 10, wherein the flexible base material is composed of a fiber base material, the flexible sheet electrode. 12. The flexible sheet electrode according to 11, wherein the fiber base material is a woven fabric or a knitted fabric, the flexible sheet electrode. 13. A wearable bioelectrode comprising the flexible sheet electrode according to any one of 1 to 12. 14. A biosensor comprising the wearable bioelectrode according to 13.

Example

[0244] Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the descriptions of these examples at all. The raw material components shown in Table 1 are shown below. (A1-1): First vinyl group-containing linear organopolysiloxane: Vinyl group-containing dimethylpolysiloxane synthesized by the following synthetic scheme 1 (structure represented by the above formula (1-1)) (A1-2): Second vinyl group-containing linear organopolysiloxane: Vinyl group-containing dimethylpolysiloxane synthesized by the following synthetic scheme 2 (structure represented by the above formula (1-1) where R 1 and R 2 are vinyl groups)

[0245] (Organohydrogenpolysiloxane (B)) (B-1): Organohydrogenpolysiloxane: manufactured by Momentive, "TC-25D"

[0246] (Silica particles (C)) (C): Silica fine particles (particle size 7 nm, specific surface area 300 m 2 / g), manufactured by Nippon Aerosil Co., Ltd., "AEROSIL 300"

[0247] (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)"

[0248] (Platinum or platinum compound (E)) (E-1): Platinum compound (manufactured by Momentive, trade name "TC-25A")

[0249] (Water (F)) (F): Pure water

[0250] (Metal powder (G)) (G1): Silver powder, manufactured by Tokushukagaku Kenkyusho Co., Ltd., trade name "TC-101", median diameter d 50 : 8.0 μm, aspect ratio 16.4, average major axis 4.6 μm

[0251] (Synthesis of vinyl group-containing organopolysiloxane (A)) [Synthesis Scheme 1: Synthesis of the first vinyl group-containing linear organopolysiloxane (A1-1)] According to the following formula (5), the first vinyl group-containing linear organopolysiloxane (A1-1) was synthesized. That is, 74.7 g (252 mmol) of octamethylcyclotetrasiloxane and 0.1 g of potassium silicate were placed in a 300 mL separable flask equipped with a condenser tube and a stirring blade, purged with Ar gas, heated, and stirred at 120 °C for 30 minutes. At this time, an increase in viscosity was confirmed. Thereafter, the temperature was raised to 155 °C and stirring was continued for 3 hours. Then, after 3 hours, 0.1 g (0.6 mmol) of 1,3-divinyltetramethyldisiloxane was added, and stirring was further continued at 155 °C for 4 hours. Furthermore, after 4 hours, it was diluted with 250 mL of toluene and then washed 3 times with water. The washed organic layer was reprecipitated and purified by washing several times with 1.5 L of methanol to separate the oligomer and the polymer. The obtained 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 ). Also, the vinyl group content calculated by 1H-NMR spectrum measurement was 0.04 mol%.

[0252] [Chemical formula]

[0253] [Synthesis Scheme 2: Synthesis of the second vinyl group-containing linear organopolysiloxane (A1-2)] In the synthesis step of the above (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, the second vinyl group-containing linear organopolysiloxane (A1-2) was synthesized as shown in the following formula (6) (Mn = 2.3×10 5 , Mw = 5.0×10 5 ) in the same manner as the synthesis step of (A1-1). Also, the vinyl group content calculated by 1H-NMR spectrum measurement was 0.93 mol%.

[0254] [Chemical formula]

[0255] (Preparation of silicone rubber-based curable composition) The silicone rubber-based curable composition of Sample 1 was 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 at the ratios 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 the addition of silica particles (C) was carried out through a first step of kneading for 1 hour under the conditions of 60 to 90 °C in a nitrogen atmosphere for the coupling reaction, and a second step of kneading for 2 hours under the conditions of 160 to 180 °C in a reduced-pressure atmosphere for the removal of by-products (ammonia). Then, it was cooled, and the remaining 10% vinyl group-containing organopolysiloxane (A) was added in two portions and kneaded for 20 minutes. Subsequently, organohydrogenpolysiloxane (B) and platinum or a platinum compound (E) were added to 100 parts by weight of the obtained kneaded product (silicone rubber compound) at the ratios shown in Table 2 below, and kneaded with a roll to obtain a silicone rubber-based curable composition.

[0256] (Preparation of Conductive Paste 1) 15.3 parts by weight of the obtained silicone rubber-based curable composition of Sample 1 was immersed in 34.8 parts by weight of decane (solvent), followed by stirring with a planetary mixer. After adding 65.2 parts by weight of metal powder (G1), it was further kneaded with a planetary mixer to obtain Conductive Paste 1 in which the total content of the silicone rubber-based curable composition and metal powder (G1) was 69.8% by weight.

[0257]

Table 1

[0258] (Fabrication of Flexible Sheet Electrode) A flexible substrate (polyester knitted fabric, basis weight 130 g / m 2 ) with a size of 7 cm × 7 cm × 0.4 mmt was placed on the plane of a SUS substrate, and then a mask (made of polyethylene terephthalate) having one opening of 5 cm × 5 cm and a thickness of 125 μm was placed on the surface of the flexible substrate. Subsequently, the above conductive paste was applied to the openings of the mask, and squeegee printing was performed using a glass plate in the printing direction perpendicular to the fiber mesh, based on the printing conditions shown in Table 2. Subsequently, the mask was removed, and the printed conductive paste 1 was dried at 140°C for 20 minutes and cured at 180°C for 2 hours to produce a flexible sheet electrode having a conductive elastomer layer provided on a flexible substrate.

[0259] In Table 2, the arithmetic mean height (Sa0) and the maximum height (Sz0) were measured for three regions (1 mm × 1 mm) on the surface of the conductive elastomer layer in the unextended state in the planar direction using a shape analysis laser microscope (manufactured by Keyence Corporation, product number: VK-X1000) with the wavelength of the laser light being 404 nm, and the average value of the three values was taken. However, the arithmetic mean height (Sa 20 ) and the maximum height (Sz 20 ) were measured for the extended region with a square electrode (conductive elastomer layer) held by two opposite sides and extended by 20% in the planar direction. For reference, on the surface of the above flexible substrate which is the surface to which the conductive paste is applied, Sa0 was 3705.9 μm and Sz0 was 4.57. Also, the adhesion amount of the conductive elastomer layer in Table 2 was calculated by subtracting the weight of the flexible substrate measured in advance from the weight of the flexible sheet electrode.

[0260]

Table 2

[0261] The following items were evaluated for the obtained flexible sheet electrode. The results are shown in Table 2. Note that in Table 2, "-" means not implemented.

[0262] (Surface resistance value) The printed portion of the obtained flexible sheet electrode was cut out into a size of 5 cm × 5 cm to prepare a sample. Using this sample, at 25°C in an unextended state or in a state where it was extended by 20% in the diagonal direction of the square-shaped electrode, the surface resistance value (Ω) at the diagonal of the square-shaped flexible sheet electrode was measured.

[0263] (Washing resistance) For the obtained flexible sheet electrode, a washing resistance test was conducted by repeating the following washing processes (1) to (4) 20 times. (1) The flexible sheet electrode was repeatedly stretched and contracted 300 times by 50% in both the vertical and horizontal directions. (2) Neutral detergent and water were put into a beaker, and the flexible sheet electrode that had been treated in (1) was immersed and stirred for 24 hours. (3) Water was put into the beaker, and the flexible sheet electrode that had been treated in (2) was immersed and stirred for 10 minutes to rinse off the detergent. (4) The flexible sheet electrode from (3) was dried in an oven at 90°C for 30 minutes.

[0264] In each example, it was confirmed that no cracks occurred in the conductive elastomer layer and no peeling occurred between the flexible substrate, maintaining the initial state. On the other hand, in Comparative Example 1, cracks in the conductive elastomer layer and peeling between the flexible substrate were confirmed. Also, after the above washing resistance test, the arithmetic mean height (Sa w0 ) and the maximum height (Sz w0 ) on the surface of the conductive elastomer layer in the unextended state were measured in the same manner as the above method. The results are shown in Table 2.

[0265] (Biosignal measurement) In the obtained flexible sheet electrode, an external connection part (a male snap button made of metal) was attached to the other surface of the flexible substrate on the side opposite to the surface where the conductive elastomer layer was formed, and the external connection part and the conductive elastomer layer were electrically connected to obtain a wearable biosensor electrode. Three wearable bioelectrodes 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 fabricate an electrocardiogram measuring device (bio-sensor). The flexible sheet electrodes provided on one side of the three wearable bioelectrodes were directly attached to the skin of the subject, and the electrocardiogram potential of the subject was measured by a three-point induction method (measurement point, reference, body ground).

[0266] As a result, it was confirmed that the electrocardiogram waveform could be monitored by using the wearable bioelectrode equipped with the flexible sheet electrode of each example. In addition, the wearable bioelectrodes equipped with the flexible sheet electrodes of Examples 1 to 3 had less noise in the electrocardiogram waveform and the S-T segment could be clearly judged as compared with the case of Comparative Example 1. Therefore, the biopotential stability of the flexible sheet electrodes of Examples 1 to 3 was evaluated as good (○), and that of Comparative Example 1 was evaluated as poor (×). The results are shown in Table 2.

[0267] The flexible sheet electrodes of each example showed excellent measurement stability in biopotential measurement such as electrocardiogram waveform as compared with Comparative Example 1. Such a flexible sheet electrode can be suitably used for a wearable bioelectrode.

Explanation of Signs

[0268] 1 Flexible sheet electrode 10 Flexible base material 11 One side 12 Main body 13 The other side 14 Extension part 20 Conductive elastomer layer 21 Impregnated layer 22 One side 24 Stretchable wiring 26 Connection part 30 External connection part 32 Mounting plate 34 Mounting pin 50 Protective layer 52 Insulating protective layer 60 Insulating elastomer layer 100 Wearable biologic electrode 200 Biosensor 210 Connector 220 Cable 230 Sensor module 240 Computer

Claims

1. A flexible sheet electrode used for measuring a bioelectric potential, comprising: a flexible substrate; a conductive elastomer layer provided on the flexible substrate; The flexible sheet electrode is characterized in that: the flexible substrate is composed of a fiber substrate; a part or all of the flexible substrate includes an impregnated layer of the conductive elastomer layer; Let Sa be the arithmetic mean height on the surface of the conductive elastomer layer at 20% elongation measured with a laser microscope having a laser light wavelength of 404 nm ２０ and let Sz be the maximum height ２０ when Sa ２０ ≤ 19.5 μm, and Sz ２０ satisfies ≤ 250 μm, Flexible sheet electrode.

2. The flexible sheet electrode according to Claim 1, Let Sa be the arithmetic mean height on the surface of the conductive elastomer layer before stretching, measured with a laser microscope having a laser light wavelength of 404 nm ０ and let Sz be the maximum height ０ when... 0 μm ≤ |Sa ２０ − Sa ０ | ≤ 10 μm, and / or 0 μm ≤ |Sz ２０ − Sz ０ | ≤ 80 μm, a flexible sheet electrode satisfying the above conditions.

3. The flexible sheet electrode according to any one of Claims 1 or 2, wherein the conductive elastomer layer includes a conductive filler and a non-conductive filler. Flexible sheet electrode.

4. The flexible sheet electrode according to Claim 3, wherein the conductive filler includes one or more selected from the group consisting of a metal-based filler, a carbon-based filler, a metal oxide filler, and a metal-plated filler. Flexible sheet electrode.

5. The flexible sheet electrode according to Claim 3 or 4, wherein the conductive filler includes flaky silver powder. Flexible sheet electrode.

6. The flexible sheet electrode according to any one of Claims 3 to 5, wherein the non-conductive filler includes silica particles. Flexible sheet electrode.

7. The flexible sheet electrode according to any one of Claims 3 to 6, wherein the content of the conductive filler is 50% by mass or more and 90% by mass or less in the conductive elastomer layer. Flexible sheet electrode.

8. The flexible sheet electrode according to any one of Claims 1 to 7, wherein the conductive elastomer layer includes one or more elastomer materials selected from the group consisting of silicone rubber, urethane rubber, and fluororubber. Flexible sheet electrode.

9. The flexible sheet electrode according to any one of Claims 1 to 8, in the conductive elastomer layer, when the surface resistance value at the time of no elongation is R1 and the surface resistance value when it is stretched by 20% in one of the in-plane directions of the surface is R2, R1 and R2 are configured to satisfy 1.0 ≦ R2 / R1 ≦ 7.

0. Flexible sheet electrode.

10. The flexible sheet electrode according to any one of Claims 1 to 9, wherein the fiber substrate is a woven fabric or a knitted fabric. Flexible sheet electrode.

11. A wearable bioelectrode comprising the flexible sheet electrode according to any one of Claims 1 to 10.

12. A biosensor comprising the wearable bioelectrode according to Claim 11.

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