Flexible sheet electrodes, wearable bioelectrodes, and biosensors

Abstract

To provide a flexible sheet electrode with excellent conductive properties after washing. [Solution] The flexible sheet electrode of the present invention comprises a flexible substrate and an elastomer electrode layer provided on the flexible substrate, wherein the elastomer electrode layer is formed on the inside of the flexible substrate and has an impregnation layer including an insulating elastomer layer, and is formed on the outside of the flexible substrate and has a laminate including a conductive elastomer layer.

Description

[Technical Field]

[0001] This invention relates to a flexible sheet electrode, a wearable bioelectrode, and a biosensor. [Background technology]

[0002] Various developments have been made regarding sheet electrodes. As an example of this type of technology, 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 the single fibers constituting the fibrous structure and / or in the gaps between the single fibers (Claim 1 of Patent Document 1, etc.). In the examples of the same document, a method for supporting the conductive polymer on the fibrous structure is described, in which a dispersion of a conductive polymer such as PEDOT / PSS and a binder in a solvent is applied to the fibrous structure at a rate of approximately 15 g / m². 2 (about 1.5mg / cm 2 The document describes a method for gravure coating to achieve the following result. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2015 / 115440 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, the electrode member described in Patent Document 1 above has not been sufficiently examined in terms of a configuration in which a conductive elastomer layer is used as the sheet-like electrode portion. As a result of the inventors' investigations, it was found that there is room for improvement in the conductive properties after washing of sheet electrodes having a conductive elastomer layer. [Means for solving the problem]

[0005] Further investigations by the inventors revealed that in a flexible sheet electrode comprising an impregnating layer that is impregnated into the interior of a flexible substrate and a laminate that is not impregnated, by configuring the impregnating layer to include an insulating elastomer layer and the laminate to include a conductive elastomer layer, it is possible to suppress the increase in surface resistivity of the flexible sheet electrode after repeated washing and improve the conductive properties after washing, thus completing the present invention.

[0006] According to the present invention, Flexible substrate and The flexible substrate comprises an elastomer electrode layer provided on the flexible substrate, The elastomer electrode layer is Formed on the inside of the aforementioned flexible substrate, the impregnation layer includes an insulating elastomer layer, Formed on the outside of the aforementioned flexible substrate, the laminate includes a conductive elastomer layer, Having, Flexible sheet electrodes are provided.

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

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

[0009] According to the present invention, a flexible sheet electrode with excellent conductive properties after washing, a wearable bioelectrode, and a biosensor using the same are provided. [Brief explanation of the drawing]

[0010] [Figure 1] This figure schematically shows an example of the configuration of the flexible sheet electrode of this embodiment ((a) cross-sectional view, (b) top view). [Figure 2] This is a schematic cross-sectional view showing an example of a modified flexible sheet electrode. [Figure 3]This is a schematic top view showing an example of the configuration of a wearable bioelectrode according to this embodiment. [Figure 4] This is a cross-sectional view taken along the arrow BB in Figure 3. [Figure 5] This is a schematic diagram illustrating an example of the configuration of the biosensor in this embodiment. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described below with reference to the drawings. In all drawings, similar components are denoted by the same reference numerals, and their descriptions are omitted as appropriate. Also, the drawings are schematic diagrams and do not correspond to the actual dimensional ratios.

[0012] The outline of the flexible sheet electrode of this embodiment will be described.

[0013] The flexible sheet electrode of this embodiment comprises a flexible substrate and an elastomer electrode layer provided on the flexible substrate. The elastomer electrode layer is formed on the inside of the flexible substrate and includes an impregnation layer containing an insulating elastomer layer, and is formed on the outside of the flexible substrate and includes a laminate containing a conductive elastomer layer.

[0014] According to the inventors' findings, it has been found that by constructing the elastomer electrode layer provided on a flexible substrate with an impregnation layer containing an insulating elastomer layer and a laminate containing a conductive elastomer layer, the deterioration of the conductive properties of the flexible sheet electrode after washing can be suppressed.

[0015] Although the detailed mechanism is not clear, it is thought that the impregnated layer maintains a state in which the laminate adheres closely to the flexible substrate through an anchoring effect, thereby suppressing peeling of the conductive elastomer layer, which functions as an electrode, from the flexible substrate even after repeated washing deformation, and thus suppressing fluctuations in surface resistivity. Furthermore, since the insulating elastomer layer typically does not contain conductive fillers and therefore is more flexible than the conductive elastomer layer, it can follow the deformation of the flexible base material during washing and maintain its adhesion. Thus, it can be inferred that the above-mentioned anchoring effect can be exerted even after washing.

[0016] According to this embodiment, a washable, flexible sheet electrode can be realized.

[0017] Flexible sheet electrodes can be applied to various uses, one of which is wearable bioelectrodes. The wearable bioelectrode of this embodiment is equipped with the flexible sheet electrode described above.

[0018] Wearable bioelectrodes can detect electrical potential fluctuations from living organisms, such as heart rate, muscle activity, and nervous system activity. For example, a wearable bioelectrode may be configured to measure at least one of the following bioelectric potentials: electrocardiogram, electromyogram, and skin potential.

[0019] According to this embodiment, a stretchable and / or bendable wearable bioelectrode can be realized. Such wearable bioelectrodes suppress wire breakage in the flexible sheet electrode even when the substrate is deformed, such as by stretching or bending, enabling stable measurement of biopotential. Furthermore, even when the substrate is deformed, delamination of the flexible sheet electrode from the flexible substrate is suppressed, and mutual adhesion is maintained.

[0020] Wearable bioelectrodes can be used as wearable devices that can be attached to either the body or clothing. Due to their elasticity, such wearable bioelectrodes can conform to the surface shape and movements of the body. In this case, the wearable bioelectrode may be attached directly to the body or to the body via a body-attaching component (clothing). Clothing with wearable bioelectrodes may, for example, have a configuration in which the wearable bioelectrode is sewn into the clothing, or a configuration in which the wearable bioelectrode is used as part of the clothing.

[0021] Wearable bioelectrodes can be further equipped with connectors and electronic components to form biosensors that can connect to external devices. These biosensors are wearable. By analyzing bioelectric potentials such as electrocardiograms detected by the biosensors, biosignal measurement systems tailored to various applications can be constructed.

[0022] Such wearable bioelectrodes, biosensors using them, and biosignal measurement systems are expected to be usable in a variety of settings, including physical diagnosis, health management, fitness, rehabilitation, and elderly care.

[0023] The configuration of the flexible sheet electrode and the wearable bioelectrode of this embodiment will be described in detail below.

[0024] <Flexible Sheet Electrode> Figure 1 is a top view showing an example of the configuration of the flexible sheet electrode 1. Figure 1(a) is a cross-sectional view of (b)AA of the flexible sheet electrode 1, and (b) is a top view of the flexible sheet electrode 1. Figure 2 is a cross-sectional view showing an example of deformation of the flexible sheet electrode 1.

[0025] The flexible sheet electrode 1 comprises a flexible substrate 10 and an elastomer electrode layer 2 provided on the flexible substrate 10.

[0026] The elastomer electrode layer 2 comprises an impregnation layer 21 which is itself impregnated into the flexible substrate 10, and a laminate 23 which is not impregnated into the flexible substrate 10.

[0027] The elastomer electrode layer 2 is not particularly limited as long as the impregnation layer 21 includes an insulating elastomer layer 60 and the laminate 23 includes a conductive elastomer layer 20, and may include one or more other layers.

[0028] The laminate 23 covers part or all of the surface of the flexible substrate 10, but it is sufficient that it covers at least the biopotential measurement range. The surface of the laminate 23 may be a smooth surface from the viewpoint of biopotential measurement. The elastomer electrode layer 2 may include an impregnation layer 21 that is bonded to the laminate 23. This impregnation layer 21 may be configured to include a conductive elastomer layer 20 and / or an insulating elastomer layer 60.

[0029] The impregnation layer 21 in Figure 1(a) is composed solely of an insulating elastomer layer 60, but is not limited to this. As shown in Figure 2(b), a conductive elastomer layer 20b may be present in part in the thickness direction.

[0030] The laminate 23 in Figure 1(a) is composed only of a conductive elastomer layer 20, but is not limited to this. As shown in Figure 2(a), an insulating elastomer layer 60a may be present in part in the thickness direction. That is, the laminate 23 may have a conductive elastomer layer 20 and another insulating elastomer layer 60b inside the conductive elastomer layer 20. This improves the flexibility of the flexible sheet electrode.

[0031] If the laminate 23 is composed of multiple layers, the electrode region of the elastomer electrode layer 2 in the outermost layer of the laminate 23 only needs to be composed of the conductive elastomer layer 20. In other words, the surface region of the laminate 23 as viewed from above is composed of the conductive elastomer layer 20, either partially or entirely.

[0032] In one of the cross-sections of the flexible sheet electrode 1 in Figure 1(a), the thickness of the impregnation layer 21 is T1, the thickness of the laminate 23 is T2, and the thickness of the flexible substrate 10 is T3. In Figure 2(a) 1, the thickness of the laminate 23 is T2, and the thickness of the conductive elastomer layer 20 in the laminate 23 is T2'.

[0033] The thickness measurement method involves cutting the flexible sheet electrode 1 in the lamination direction, observing one of the cross-sections with an electron microscope to obtain an SEM image of a predetermined area, for example, 1 mm × 1 mm, and then determining the thickness of each layer, such as the thickness (T1) of the impregnation layer 21 in which the elastomer electrode layer 2 is impregnated into the flexible substrate 10, the thickness (T2) of the lamination 23 in which the elastomer electrode layer 2 is not impregnated into the flexible substrate 10, and the thickness (T3) of the flexible substrate 10, based on the SEM image.

[0034] T1 and T2 are configured such that, for example, 0.1 ≤ T1 / T2 ≤ 100. The lower limit of T1 / T2 is, for example, 0.1 or higher, preferably 0.2 or higher, and more preferably 0.3 or higher. This improves the adhesion between the conductive elastomer layer and the flexible substrate, as well as the washing resistance. The upper limit of T1 / T2 is, for example, 100 or less, preferably 50 or less, and more preferably 30 or less. This improves conductivity.

[0035] T2 and T2' are configured such that, for example, 0.02 ≤ T2' / T2 ≤ 1. The lower limit of T2' / T2 is, for example, 0.02 or higher, preferably 0.05 or higher, and more preferably 0.1 or higher. This improves conductivity and wash durability. The upper limit of T2' / T2 is, for example, 1 or less, preferably 0.8 or less, and more preferably 0.5. This increases the flexibility of the flexible sheet electrode.

[0036] T1 and T3 are configured such that, for example, 0.01 ≤ T1 / T3 ≤ 1. The lower limit of T1 / T3 is, for example, 0.01 or higher, preferably 0.1 or higher, and more preferably 0.3 or higher. This improves the adhesion between the conductive elastomer layer and the flexible substrate, as well as the washing resistance. The upper limit of T1 / T3 is, for example, 1 or less, preferably 0.8 or less, and more preferably 0.7 or less. This suppresses the decrease in flexibility of the flexible sheet electrode.

[0037] The lower limit of the amount of conductive elastomer layer 20 contained in the elastomer electrode layer 2 is, for example, 10 mg / cm³. 2 Preferably 15 mg / cm³ 2 More preferably 20 mg / cm³ 2 That's all. This improves conductivity. The upper limit of the amount of conductive elastomer layer 20 contained in the elastomer electrode layer 2 is, for example, 100 mg / cm³.2 Hereinafter, preferably 80 mg / cm 2 or less, more preferably 60 mg / cm 2 or less. Thereby, a decrease in the flexibility of the flexible sheet electrode can be suppressed.

[0038] The lower limit of the adhesion amount of the insulating elastomer layer 60 contained in the elastomer electrode layer 2 is, for example, 1 mg / cm 2 or more, preferably 5 mg / cm 2 or more, more preferably 10 mg / cm 2 or more. Thereby, the flexibility of the flexible sheet electrode can be enhanced. The upper limit of the adhesion amount of the insulating elastomer layer 60 contained in the elastomer electrode layer 2 is, for example, 40 mg / cm 2 or less, preferably 35 mg / cm 2 or less, more preferably 30 mg / cm 2 or less may also be used.

[0039] As shown in FIG. 1(b), the elastomer electrode layer 2 is configured in a sheet shape, and when viewed from the upper surface direction of the flexible sheet electrode 1, the top view shape may be, for example, a square shape, a circular shape, an elliptical shape, or other polygonal shapes. In this specification, the sheet shape means that when the thickness of the laminate 23 of the elastomer electrode layer 2 is D (mm) and the area of one surface 22 in the top view of the laminate 23 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, but for example, S / D ≦ 10 7 may also be used.

[0040] The elastomer electrode layer 2 and the conductive elastomer layer 20 have elasticity.

[0041] In this specification, elasticity is expressed as the elongation rate when stretched in a predetermined direction. The predetermined direction may be, for example, the direction in the top view of Figure 1 where the conductive elastomer layer 20, specifically the conductive elastomer layer 20, has its maximum length. If the top view shape of the conductive elastomer layer 20 is rectangular, it may be stretched in the diagonal direction. When stretched in this extending direction, "stretchable" means that the elongation rate can be extended to, for example, 10% or more, preferably 20% or more, and more preferably 50% or more, and that the conductive elastomer layer 20 does not break at that elongation rate.

[0042] In addition, resistivity measurements, such as surface resistivity, may be performed by measuring the surface of the conductive elastomer layer 20 using the four-probe method.

[0043] 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 conductive paste. Therefore, a flexible sheet electrode with excellent design flexibility for the sheet electrode can be provided.

[0044] The flexible base material 10 is not particularly limited as long as it is a base material that can be stretched and / or bent, but for example it may be composed of a fibrous base material, a porous elastomer base material, or an elastomer base material. As the elastomer base material, one containing an insulating elastomer as described later may be used.

[0045] Examples of fiber structural materials for fiber base materials include natural fibers such as plant fibers and animal fibers; and chemical fibers such as inorganic fibers, regenerated fibers, semi-synthetic fibers, and synthetic fibers. These may be used individually or in combination of two or more types. Among these, from the viewpoint of durability, chemical fibers may be used, as may synthetic fibers such as acrylic, polyester, nylon, and polyurethane.

[0046] The fibrous substrate can be any known fibrous substrate, but it may be composed of either an insulating material or a conductive material, or both, for example.

[0047] The lower limit of the basis weight of the fiber base material is, for example, 10 g / m². 2 Preferably 20 g / m² 2 Above, a comfortable 30g / m 2 That concludes the explanation. This will increase the mechanical strength. On the other hand, the upper limit for the basis weight of the fiber base material is, for example, 500 g / m². 2 Preferably 400 g / m² 2 More preferably, 350 g / m² 2 The following is the result: This helps to suppress the decrease in flexibility. It also allows for an increase in the degree of impregnation of the conductive elastomer layer.

[0048] The structure of the fibrous base material is not limited, but from the viewpoint of flexibility, woven or knitted fabrics may be used.

[0049] The upper limit of the thickness T3 of the flexible substrate 10 can be set according to the application, for example, it may be 10 mm or less, preferably 1 mm or less, but more preferably 600 μm or less from the viewpoint of wearable device applications. By setting it to 600 μm or less, a thin film sheet-like wearable bioelectrode can be realized. The lower limit of the thickness T3 of the flexible substrate 10 is, from the viewpoint of mechanical strength, for example, 10 μm or more, preferably 50 μm or more, and more preferably 100 μm or more.

[0050] An example of a manufacturing method for the flexible sheet electrode 1, using screen printing, will be described. First, a support is placed on the workbench, and the flexible substrate 10 is placed on the support. Next, a mask having a predetermined opening pattern shape is placed on the flexible substrate 10. Next, insulating paste and conductive paste are applied to the flexible substrate 10 using a squeegee, via a mask. The application order of the insulating paste and conductive paste can be changed as appropriate depending on the lamination structure of the elastomer electrode layer 2. Drying treatment may be performed during the application process as needed. Subsequently, the insulating paste and conductive paste are subjected to a curing treatment. If the insulating paste and conductive paste contain a silicone rubber-based curable composition, the curing temperature can be set to 160°C to 220°C, and the curing time to 1 to 3 hours, for example. The mask is removed after or before the curing treatment. Subsequently, the flexible substrate 10 support is separated to obtain the flexible sheet electrode 1.

[0051] In this embodiment, by appropriately selecting, for example, the manufacturing method of the flexible sheet electrode 1, it is possible to control the thickness T1 of the impregnation layer 21, the thickness T2 of the laminate 23, the thickness of the conductive elastomer layer 20 in the impregnation layer 21, the thickness of the insulating elastomer layer 60 in the laminate 23, and the amount of adhesion of the conductive elastomer layer 20 and / or insulating elastomer layer 60. Among these, for example, appropriately selecting the thickness of the mask, the number of mask layers, the number of coatings, and the solid content concentration of the insulating paste and conductive paste are examples of factors that can bring the above thickness and adhesion amount into a desired numerical range.

[0052] <Wearable Bioelectrodes> Figure 3 is a top view showing an example of the configuration of the wearable bioelectrode 100. Figure 4 is a cross-sectional view of BB in Figure 3. The wearable bioelectrode 100 comprises a flexible sheet electrode 1 having a flexible substrate 10 and an elastomer electrode layer 2 including a conductive elastomer layer 20.

[0053] The wearable bioelectrode 100 can detect bioelectrical signals generated from biological activities such as the heart, muscles, skin, and nerves by having one surface 22 of the conductive elastomer layer 20 follow the body of the subject. When the wearable bioelectrode 100 has multiple conductive elastomer layers 20 in the in-plane direction of the flexible substrate 10, it can be suitably used as an electrode for measuring electrocardiogram waveforms.

[0054] Subjects include humans, non-human animals, and others.

[0055] The wearable bioelectrode 100 can be used as a simple and reusable dry sensor, rather than a wet sensor that requires the application of gel to the measurement area of ​​the subject.

[0056] The flexible substrate 10 has an electrode-forming region on which a conductive elastomer layer 20 is formed when viewed from above. In this electrode-forming region, the flexible substrate 10 and the conductive elastomer layer 20 adhere closely together when not stretched or when stretched, thereby increasing the overall mechanical strength of the wearable bioelectrode 100.

[0057] Furthermore, the flexible substrate 10 may have an electrode-free region around the electroformed region where the conductive elastomer layer 20 is not formed. Attachments such as sewing threads or snap buttons for attachment to clothing can be attached to this electrode-free region. Alternatively, when the wearable bioelectrode 100 is wrapped around the body, such as the wrist or ankle, the electrode-free regions of the flexible substrate 10 may be overlapped in the thickness direction to secure it to the body.

[0058] An example of the flexible substrate 10 is shown in Figure 3, in which at least a part of it, for example, the main body 12, has a band shape that can be wrapped around the body. Such a wearable bioelectrode 100 has a structure suitable for a band-type bioelectrode that can be wrapped around a part of the body, such as the wrist or ankle.

[0059] Furthermore, the band-type flexible base material 10 in Figure 3 may have a main body 12 and an expansion portion 14 that protrudes in the in-plane direction of the main body 12. Even when the main body 12 is deformed into a ring structure or the like, deformation of the expansion portion 14 is suppressed. Therefore, connection failures at the external connection portion 30 attached to the expansion portion 14 can be suppressed.

[0060] The conductive elastomer layer 20 is configured in a sheet shape and has an exposed surface that comes into direct contact with the body. In this specification, "sheet-like" means that the thickness of the conductive elastomer layer 20 is D (mm), and the area of ​​one surface 22 of the conductive elastomer layer 20 as viewed from above is S (mm). 2When this is the case, S and D are, for example, 50 ≤ S / D, preferably 200 ≤ S / D, more preferably 400 ≤ S / D. The upper limit of S / D can be set according to the measurement site of the subject and is not particularly limited, but for example, S / D ≤ 10 7 But that's fine.

[0061] The conductive elastomer layer 20 comes into contact with the body when the wearable bioelectrode 100 is in use and can conform well to the contact surface, taking into account the surface shape and deformation of the body.

[0062] The wearable bioelectrode 100 may be configured to be connected to the outside by a conductive elastomer layer 20, or it may be configured to be connected to a connecting portion 26, which is a separate component electrically connected to the conductive elastomer layer 20. As shown in Figure 3, this connecting portion 26 may be configured to be electrically connected to the conductive elastomer layer 20 via an expandable wire 24.

[0063] The conductive elastomer layer 20, the stretchable wiring 24, and the connecting portion 26 are made of the same / different conductive elastomer, preferably the same conductive elastomer.

[0064] Each component of the conductive elastomer layer 20 may be composed of a printed layer formed by a printing method using a conductive paste. In this case, each component, including the conductive elastomer layer 20, the stretchable wiring 24, and the connecting portion 26, may be seamlessly connected to one another.

[0065] The external connection section 30 can send bioelectric signals detected through the conductive elastomer layer 20 to external electronic components, etc.

[0066] The wearable bioelectrode 100 shown in Figure 3 includes an external connection part 30. The external connection portion 30 is provided on the flexible substrate 10 opposite to the conductive elastomer layer 20. For example, the external connection portion 30 in Figure 2 is formed on the other surface 13 of the flexible substrate 10. This prevents the external connection portion 30 from coming into contact with the body together with the conductive elastomer layer 20 when the wearable bioelectrode 100 is in use, thereby suppressing interference with the detection of bioelectrical signals.

[0067] The external connection part 30 is not particularly limited as long as it is configured to be electrically connected to the conductive elastomer layer 20, but it is made of a conductive material such as a metal material or a conductive elastomer.

[0068] The shape of the external connection part 30 is not particularly limited, but it may have a connector that can be connected to electronic components or a structure that facilitates wiring.

[0069] An example of the external connection part 30 may be a metal snap button. The external connection part 30 in Figure 4 is a male snap button and is fixed to the flexible base material 10 using a metal mounting plate 32 and mounting pin 34. By fixing the flexible base material 10 by sandwiching it between the external connection part 30 and the mounting plate 32, misalignment of the fixing position of the external connection part 30 can be suppressed. The mounting pin 34 contacts a part of the conductive elastomer layer 20, for example, the connection part 26, thereby enabling electrical connection between the conductive elastomer layer 20 and the external connection part 30.

[0070] Furthermore, part or all of the mounting plate 32 in Figure 4 is covered with an insulating protective layer 52. The insulating protective layer 52 prevents contact between the mounting plate 32 and the body. The insulating protective layer 52 may be made of an insulating material, for example, an insulating elastomer such as silicone rubber.

[0071] The biosensor of this embodiment will now be described.

[0072] Depending on the application, the biosensor comprises one wearable bioelectrode 100 or two or more wearable bioelectrodes 100. The biosensor may be directly attached to the body, or it may be attached to a body attachment component such as clothing.

[0073] The biosensor includes electronic components that can be electrically connected to the wearable bioelectrode 100 via an external connection part 30.

[0074] Various known electronic components can be used depending on the application, but examples include amplifiers, AD converters, CPUs, memory, communication circuits, wireless communication units, analog filters, capacitors, resistors, and batteries. One or more of these may be modularized on a circuit board. This allows the biosensor to be used as a wearable device. Furthermore, other sensors such as acceleration sensors, temperature sensors, and pressure sensors may be used in combination as electronic components.

[0075] Figure 5 is a diagram illustrating an example of the configuration of the biosensor 200. The biosensor 200 in Figure 5 comprises a wearable bioelectrode 100, a connector 210, a cable 220, a sensor module 230, and a computer 240.

[0076] The connector 210 has a structure that allows it to be electrically coupled to the external connection part 30 of the wearable bioelectrode 100, and may have, for example, a female snap button. Cable 220 electrically connects connector 210 to the electronic components, sensor module 230 and computer 240. The sensor module 230 can be used with an ECG sensor module when measuring electrocardiogram waveforms. The sensor module 230 has an electrical circuit that suppresses interference from external RF sources, line frequencies, and electrical noise, and can suppress noise when measuring bioelectrical signals. Computer 240 can acquire bioelectrical signals and generate and output waveforms of bioelectric potentials such as surface electromyography, electrocardiogram, skin potential, and electroencephalography. Computer 240 may also use a single-board computer consisting of a printed circuit board equipped with a CPU, peripheral components, input / output interfaces, connectors, etc.

[0077] The biosignal measurement system of this embodiment will now be described. A biosignal measurement system is equipped with a biosensor. A biosignal measurement system may be a system (measuring device) that displays, analyzes, or stores data received from a biosensor.

[0078] The materials for the conductive elastomer layer 20 and the insulating elastomer layer 60 will be described below.

[0079] The conductive elastomer layers 20, 20a, and 20b in the flexible sheet electrode 1 may each contain a conductive elastomer. The insulating elastomer layers 60, 60a, and 60b in the flexible sheet electrode 1 may each contain an insulating elastomer. The insulating elastomer and the conductive elastomer may contain the same or different elastomer materials.

[0080] Insulating elastomers can include, for example, silicone rubber, urethane rubber, fluororubber, nitrile rubber, acrylic rubber, styrene rubber, chloroprene rubber, ethylene propylene rubber, and the like. Among these, the elastomer includes one or more thermosetting elastomers (elastomer materials) selected from the group consisting of silicone rubber, urethane rubber, and fluororubber. An insulating elastomer may consist of an elastomer material alone, or it may be composed of an elastomer material and a non-conductive filler. An example of an insulating elastomer includes silicone rubber, preferably silicone rubber and a non-conductive filler. Among elastomers, silicone rubber is chemically stable and also has excellent mechanical strength. Among these, from a hygienic standpoint, it is preferable to use silicone rubber, which has high biocompatibility, as the elastomer material.

[0081] Conductive elastomers can include, for example, silicone rubber, urethane rubber, fluororubber, nitrile rubber, acrylic rubber, styrene rubber, chloroprene rubber, ethylene propylene rubber, and the like. Among these, the elastomer includes one or more thermosetting elastomers (elastomer materials) selected from the group consisting of silicone rubber, urethane rubber, and fluororubber, and a conductive filler. A preferred example of a conductive elastomer includes silicone rubber and a conductive filler. This enhances the elasticity and conductivity of the conductive elastomer.

[0082] At least one, preferably both, of the insulating elastomer and the conductive elastomer may contain a non-conductive filler. Known materials can be used as the non-conductive filler, such as silica particles, silicone rubber particles, or talc. Among these, silica particles may also be included.

[0083] The conductive filler may include, for example, one or more selected from the group consisting of powdered or fibrous metal-based fillers, carbon-based fillers, metal oxide fillers, and metal-plated fillers. Among these, a metal-based filler such as silver powder may be used as the conductive filler.

[0084] The conductive elastomer may further contain non-conductive fillers in addition to the conductive fillers. This can enhance the mechanical properties of the conductive elastomer.

[0085] A specific example is that the conductive elastomer layer 20 may contain silver powder as a conductive filler, preferably in the form of flake silver powder. This can improve conductivity and, moreover, stretch conductivity. Furthermore, the conductive elastomer layer 20 may also contain silver powder and silica particles as a non-conductive filler. This improves the stretchability and durability of the conductive elastomer layer 20.

[0086] At least two or all of the conductive elastomer of the conductive elastomer layer 20 and the insulating elastomer of the insulating elastomer layer 60 may be configured to include the same elastomer material.

[0087] In this specification, "containing the same elastomer material" means that each contains at least one of the same type of elastomer material from among the types of thermosetting elastomers exemplified above. Furthermore, if the same silicone rubber is included, this silicone rubber may be composed of a cured product of a silicone rubber-based curable composition containing a vinyl group-containing organopolysiloxane. From the viewpoint of mechanical strength and other factors, it is preferable that the insulating elastomer layer 60 and / or the conductive elastomer layer 20 contain silicone rubber.

[0088] The insulating elastomer may be composed of a cured product of a silicone rubber-based curable composition containing a vinyl group-containing organopolysiloxane. The conductive elastomer may be composed of a conductive filler and a cured product of a silicone rubber-based curable composition containing a vinyl group-containing organopolysiloxane.

[0089] The components of the silicone rubber-based curable composition are described in detail below.

[0090] In this specification, "containing the same silicone rubber" means that the silicone rubber-based curable composition contains at least the same type of vinyl group-containing linear organopolysiloxane, and may further contain one or more selected from the group consisting of the same type of crosslinking agent, the same type of nonconductive filler, the same type of silane coupling agent, and the same type of catalyst.

[0091] A linear organopolysiloxane containing the same type of vinyl group is defined as one that contains at least the same vinyl group as a functional group and has a linear structure, even if the amount of vinyl groups in the molecule, the molecular weight distribution, or the amount added differs.

[0092] Similar crosslinking agents only need to have a common structure, such as a linear or branched structure, and may have different molecular weight distributions and functional groups, as well as different amounts added.

[0093] Non-conductive fillers of the same type only need to have at least common constituent materials, and may differ in particle size, specific surface area, surface treatment agent, or the amount of such agent added.

[0094] Similar silane coupling agents only need to have at least one common functional group; other functional groups in the molecule and the amount added may differ.

[0095] Catalysts of the same type only need to have at least common constituent materials; they may contain different compositions, and the amounts of these compositions added may differ.

[0096] A silicone rubber-based curable composition comprising the same silicone rubber may further contain one or more different types selected from the group consisting of vinyl group-containing linear organopolysiloxanes, crosslinking agents, nonconductive fillers, silane coupling agents, and catalysts.

[0097] The silicone rubber-based curable composition of this embodiment may contain a vinyl group-containing organopolysiloxane (A). The vinyl group-containing organopolysiloxane (A) is a polymer that forms the main component of the silicone rubber-based curable composition of this embodiment.

[0098] The vinyl group-containing organopolysiloxane (A) may include a vinyl group-containing linear organopolysiloxane (A1) having a linear structure.

[0099] The above vinyl group-containing linear organopolysiloxane (A1) has a linear structure and contains vinyl groups, which serve as crosslinking points during curing.

[0100] The vinyl group content of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but it is preferable that it has two or more vinyl groups in the molecule and that the content is 15 mol% or less. This optimizes the amount of vinyl groups in the vinyl group-containing linear organopolysiloxane (A1) and ensures the formation of a network with the components described later.

[0101] In this specification, "~" indicates that the upper and lower limits are included unless otherwise specified.

[0102] In this specification, the vinyl group content refers to the mole percent of vinyl group-containing siloxane units when the total number of units constituting the vinyl group-containing linear organopolysiloxane (A1) is considered to be 100 mol%. However, it is assumed that there is one vinyl group per vinyl group-containing siloxane unit.

[0103] Furthermore, the degree of polymerization of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but is preferably in the range of 1000 to 10000, and more preferably in the range of 2000 to 5000. The degree of polymerization can be determined, for example, by the number-average degree of polymerization (or number-average molecular weight) in terms of polystyrene in GPC (gel permeation chromatography) using chloroform as the developing solvent.

[0104] Furthermore, the specific gravity of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but is preferably in the range of 0.9 to 1.1.

[0105] By using a vinyl group-containing linear organopolysiloxane (A1) having a degree of polymerization and specific gravity within the above-mentioned range, the heat resistance, flame retardancy, and chemical stability of the resulting silicone rubber can be improved.

[0106] The vinyl group-containing linear organopolysiloxane (A1) is preferably one having a structure represented by the following formula (1).

[0107] [ka]

[0108] In formula (1), R 1 The group is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, or a hydrocarbon group having 1 to 10 carbon atoms. Examples of alkyl groups having 1 to 10 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. Examples of alkenyl groups having 1 to 10 carbon atoms include vinyl, allyl, and butenyl groups, with vinyl being preferred. Examples of aryl groups having 1 to 10 carbon atoms include phenyl.

[0109] Also, R 2 The C1-C10 alkyl group is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, or a hydrocarbon group having 1 to 10 carbon atoms. Examples of C1-C10 alkyl groups include methyl, ethyl, and propyl groups, with methyl being preferred. Examples of C1-C10 alkenyl groups include vinyl, allyl, and butenyl groups. An example of a C1-C10 aryl group is the phenyl group.

[0110] Also, R 3 This group is a substituted or unsubstituted alkyl group, aryl group, or hydrocarbon group having 1 to 8 carbon atoms. Examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. An example of an aryl group having 1 to 8 carbon atoms is the phenyl group.

[0111] Furthermore, R in equation (1) 1 and R 2Examples of substituents include methyl groups and vinyl groups, and R 3 Examples of substituents include methyl groups.

[0112] Note that in equation (1), multiple R 1 These are independent of each other, and may be different from each other or the same. Furthermore, R 2 , and R 3 The same applies to this matter.

[0113] Furthermore, m and n are the number of repeating units constituting the vinyl group-containing linear organopolysiloxane (A1) represented by formula (1), where m is an integer from 0 to 2000 and n is an integer from 1000 to 10000. Preferably, m is from 0 to 1000 and n is from 2000 to 5000.

[0114] Furthermore, a specific structure of the vinyl group-containing linear organopolysiloxane (A1) represented by formula (1) is, for example, the one represented by the following formula (1-1).

[0115] [ka]

[0116] In formula (1-1), R 1 and R 2 Each of these is independently either a methyl group or a vinyl group, and at least one of them is a vinyl group.

[0117] The vinyl group-containing linear organopolysiloxane (A1) may include a first vinyl group-containing linear organopolysiloxane (A1-1) having two or more vinyl groups in the molecule and containing 0.4 mol% or less. The amount of vinyl groups in the first vinyl group-containing linear organopolysiloxane (A1-1) may be 0.1 mol% or less.

[0118] Furthermore, the vinyl group-containing linear organopolysiloxane (A1) may contain a first vinyl group-containing linear organopolysiloxane (A1-1) and a second vinyl group-containing linear organopolysiloxane (A1-2) having a vinyl group content of 0.5 to 15 mol%.

[0119] By combining a first vinyl group-containing linear organopolysiloxane (A1-1) and a second vinyl group-containing linear organopolysiloxane (A1-2) with a high vinyl group content, the vinyl groups can be unevenly distributed, allowing for more effective formation of crosslink density variations within the crosslinking network of the silicone rubber. As a result, the tear strength of the silicone rubber can be more effectively increased.

[0120] Specifically, it is preferable to use, for example, a first vinyl group-containing linear organopolysiloxane (A1-1) having two or more units in the molecule where R1 is a vinyl group and / or R2 is a vinyl group in the above formula (1-1), and containing 0.4 mol% or less of these units, and a second vinyl group-containing linear organopolysiloxane (A1-2) containing 0.5 to 15 mol% of units where R1 is a vinyl group and / or R2 is a vinyl group.

[0121] Furthermore, the first vinyl group-containing linear organopolysiloxane (A1-1) preferably has a vinyl group content of 0.01 to 0.2 mol%. Also, the second vinyl group-containing linear organopolysiloxane (A1-2) preferably has a vinyl group content of 0.8 to 12 mol%.

[0122] Furthermore, when a first vinyl group-containing linear organopolysiloxane (A1-1) and a second vinyl group-containing linear organopolysiloxane (A1-2) are combined, the ratio of (A1-1) to (A1-2) is not particularly limited, but for example, a weight ratio of (A1-1):(A1-2) of 50:50 to 95:5 is preferred, and a weight ratio of 80:20 to 90:10 is more preferred.

[0123] Furthermore, the first and second vinyl group-containing linear organopolysiloxanes (A1-1) and (A1-2) may be used individually or in combination of two or more types.

[0124] Furthermore, the vinyl group-containing organopolysiloxane (A) may also include a vinyl group-containing branched organopolysiloxane (A2) having a branched structure.

[0125] <<Organohydrogenpolysiloxane (B)>> The silicone rubber-based curable composition of this embodiment may contain organohydrogenpolysiloxane (B). Organohydrogenpolysiloxanes (B) are classified into linear organohydrogenpolysiloxanes (B1) having a linear structure and branched organohydrogenpolysiloxanes (B2) having a branched structure, and may include either one or both of these.

[0126] Linear organohydrogenpolysiloxane (B1) is a polymer having a linear structure and a structure in which hydrogen is directly bonded to Si (≡Si-H), and undergoes a hydrosilylation reaction with vinyl groups of vinyl group-containing organopolysiloxane (A), as well as vinyl groups of components blended into silicone rubber-based curable compositions, thereby crosslinking these components.

[0127] The molecular weight of the linear organohydrogenpolysiloxane (B1) is not particularly limited, but for example, it is preferable that the weight-average molecular weight is 20,000 or less, and more preferably 1,000 or more and 10,000 or less.

[0128] The weight-average molecular weight of linear organohydrogenpolysiloxane (B1) can be measured, for example, by converting it to polystyrene equivalent in GPC (gel permeation chromatography) using chloroform as the developing solvent.

[0129] Furthermore, it is preferable that the linear organohydrogenpolysiloxane (B1) does not typically have vinyl groups. This effectively prevents the crosslinking reaction from proceeding within the linear organohydrogenpolysiloxane (B1) molecule.

[0130] As the linear organohydrogenpolysiloxane (B1) described above, one having the structure represented by the following formula (2) is preferably used.

[0131] [ka]

[0132] In formula (2), R 4 The group is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, a hydrocarbon group formed by combining these groups, or a hydride group, all having 1 to 10 carbon atoms. Examples of alkyl groups having 1 to 10 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. Examples of alkenyl groups having 1 to 10 carbon atoms include vinyl, allyl, and butenyl groups. An example of an aryl group having 1 to 10 carbon atoms is the phenyl group.

[0133] Also, R 5 The group is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, hydrocarbon group, or hydride group having 1 to 10 carbon atoms. Examples of alkyl groups having 1 to 10 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. Examples of alkenyl groups having 1 to 10 carbon atoms include vinyl, allyl, and butenyl groups. An example of an aryl group having 1 to 10 carbon atoms is the phenyl group.

[0134] Note that in equation (2), multiple R 4 These are independent of each other, and may be different from each other or the same. 5 The same applies to multiple Rs. 4 and R5 Of these, at least two are hydride groups.

[0135] Also, R 6 R is a substituted or unsubstituted alkyl group, aryl group, or hydrocarbon group having 1 to 8 carbon atoms. Examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. An example of an aryl group having 1 to 8 carbon atoms is the phenyl group. Multiple R 6 These are independent of each other, and may be different from each other or the same.

[0136] Note that R in equation (2) 4 ,R 5 ,R 6 Examples of substituents include methyl groups and vinyl groups, and methyl groups are preferred from the viewpoint of preventing intramolecular crosslinking reactions.

[0137] Furthermore, m and n are the number of repeating units constituting the linear organohydrogenpolysiloxane (B1) represented by formula (2), where m is an integer from 2 to 150 and n is an integer from 2 to 150. Preferably, m is an integer from 2 to 100 and n is an integer from 2 to 100.

[0138] Furthermore, linear organohydrogenpolysiloxane (B1) may be used alone or in combination of two or more types.

[0139] The branched organohydrogenpolysiloxane (B2) has a branched structure, which allows it to form regions with high crosslink density, and it is a component that greatly contributes to the formation of a dense-sparse crosslink structure in the silicone rubber system. Also, similar to the linear organohydrogenpolysiloxane (B1) described above, it has a structure in which hydrogen is directly bonded to Si (≡Si-H), and it is a polymer that undergoes hydrosilylation reactions with the vinyl groups of vinyl group-containing organopolysiloxane (A) as well as the vinyl groups of components blended into the silicone rubber curable composition, thereby crosslinking these components.

[0140] Furthermore, the specific gravity of branched organohydrogenpolysiloxane (B2) is in the range of 0.9 to 0.95.

[0141] Furthermore, it is preferable that the branched organohydrogenpolysiloxane (B2) does not typically have vinyl groups. This effectively prevents the crosslinking reaction from proceeding within the branched organohydrogenpolysiloxane (B2) molecule.

[0142] Furthermore, the branched organohydrogenpolysiloxane (B2) is preferably the one shown in the following average composition formula (c).

[0143] Average composition formula (c) (H a (R 7 ) 3-a SiO 1 / 2 ) m (SiO 4 / 2 ) n (In equation (c), R 7 H is a monovalent organic group, a is an integer in the range of 1 to 3, and m is H a (R 7 ) 3-a SiO 1 / 2 The number of units, n is SiO 4 / 2 (The number of units)

[0144] In equation (c), R 7 The group is a monovalent organic group, preferably a substituted or unsubstituted alkyl group, aryl group, or hydrocarbon group having 1 to 10 carbon atoms. Examples of alkyl groups having 1 to 10 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. An example of an aryl group having 1 to 10 carbon atoms is the phenyl group.

[0145] In formula (c), a is the number of hydride groups (hydrogen atoms directly bonded to Si), and is an integer in the range of 1 to 3, preferably 1.

[0146] Also, in equation (c), m is H a(R 7 ) 3-a SiO 1 / 2 The number of units, n is SiO 4 / 2 It is the number of units.

[0147] Branched organohydrogenpolysiloxane (B2) has a branched structure. Linear organohydrogenpolysiloxane (B1) and branched organohydrogenpolysiloxane (B2) differ in their structure, with the number of alkyl groups R attached to Si (R / Si) being 1 when the number of Si is taken as 1. For linear organohydrogenpolysiloxane (B1), the range is 1.8 to 2.1, while for branched organohydrogenpolysiloxane (B2), it is 0.8 to 1.7.

[0148] Furthermore, because branched organohydrogenpolysiloxane (B2) has a branched structure, the amount of residue when heated to 1000°C at a heating rate of 10°C / min under a nitrogen atmosphere is 5% or more. In contrast, because linear organohydrogenpolysiloxane (B1) is linear, the amount of residue after heating under the above conditions is almost zero.

[0149] Furthermore, a specific example of a branched organohydrogenpolysiloxane (B2) is one having a structure represented by the following formula (3).

[0150] [ka]

[0151] In formula (3), R 7 R is a substituted or unsubstituted alkyl group, aryl group, or a hydrocarbon group combining these, or a hydrogen atom, having 1 to 8 carbon atoms. Examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, and propyl groups, with methyl being preferred. An example of an aryl group having 1 to 8 carbon atoms is the phenyl group. 7 Examples of substituents include methyl groups.

[0152] Note that in equation (3), multiple R 7 These are independent of each other, and may be different from each other or the same.

[0153] Furthermore, in equation (3), "-O-Si≡" indicates that Si has a branched structure that extends in three dimensions.

[0154] Furthermore, branched organohydrogenpolysiloxane (B2) may be used alone or in combination of two or more types.

[0155] Furthermore, the amount of hydrogen atoms (hydride groups) directly bonded to Si in the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) is not particularly limited. However, in the silicone rubber-based curable composition, it is preferable that the total amount of hydride groups in the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) is 0.5 to 5 moles, and more preferably 1 to 3.5 moles, per mole of vinyl groups in the vinyl group-containing linear organohydrogenpolysiloxane (A1). This ensures the reliable formation of a crosslinking network between the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) and the vinyl group-containing linear organohydrogenpolysiloxane (A1).

[0156] <<Silica particles (C)>> The silicone rubber-based curable composition of this embodiment may optionally contain silica particles (C) as a non-conductive filler.

[0157] The silica particles (C) are not particularly limited, but for example, fumed silica, calcined silica, precipitated silica, etc., can be used. These may be used individually or in combination of two or more types.

[0158] Silica particles (C) have a specific surface area of, for example, 50-400 m² as determined by the BET method.2 It is preferable that the amount is / g, and 100-400m 2 It is more preferable that the amount is / g. Furthermore, the average primary particle size of the silica particles (C) is preferably, for example, 1 to 100 nm, and more preferably about 5 to 20 nm.

[0159] By using silica particles (C) within the specified range of specific surface area and average particle size, the hardness and mechanical strength of the resulting silicone rubber can be improved, particularly its tensile strength.

[0160] <<Silane coupling agent (D)>> The silicone rubber-based curable composition of this embodiment may contain a silane coupling agent (D). The silane coupling agent (D) may have a hydrolyzable group. The hydrolyzable group is hydrolyzed by water to a hydroxyl group, and this hydroxyl group undergoes a dehydration condensation reaction with the hydroxyl groups on the surface of the silica particles (C), thereby modifying the surface of the silica particles (C).

[0161] Furthermore, this silane coupling agent (D) may include a silane coupling agent having hydrophobic groups. As a result, these hydrophobic groups are imparted to the surface of the silica particles (C), which is expected to reduce the cohesive force of the silica particles (C) in the silicone rubber curable composition and, consequently, in the silicone rubber itself (reduced aggregation due to hydrogen bonding by silanol groups). This is expected to improve the dispersibility of the silica particles in the silicone rubber curable composition. This increases the interface between the silica particles and the rubber matrix, thereby increasing the reinforcing effect of the silica particles. Moreover, it is expected that the slipperiness of the silica particles within the matrix improves during deformation of the rubber matrix. As a result of the improved dispersibility and slipperiness of the silica particles (C), the mechanical strength of the silicone rubber due to the silica particles (C) (e.g., tensile strength and tear strength) is improved.

[0162] Furthermore, the silane coupling agent (D) may include a silane coupling agent having vinyl groups. This introduces vinyl groups to the surface of the silica particles (C). Therefore, during the curing of the silicone rubber-based curable composition, that is, when the vinyl groups of the vinyl group-containing organopolysiloxane (A) and the hydride groups of the organohydrogenpolysiloxane (B) undergo a hydrosilylation reaction to form a network (crosslinked structure), the vinyl groups of the silica particles (C) also participate in the hydrosilylation reaction with the hydride groups of the organohydrogenpolysiloxane (B), thus incorporating the silica particles (C) into the network. This makes it possible to achieve lower hardness and higher modulus in the formed silicone rubber.

[0163] 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.

[0164] Examples of silane coupling agents (D) include those represented by the following formula (4).

[0165] Y n -Si-(X) 4-n ...(4) In formula (4) above, n represents an integer from 1 to 3. Y represents a functional group that has a hydrophobic group, a hydrophilic group, or a vinyl group, and when n is 1, it is a hydrophobic group, and when n is 2 or 3, at least one of them is a hydrophobic group. X represents a hydrolyzable group.

[0166] Hydrophobic groups are alkyl groups, aryl groups, or hydrocarbon groups having 1 to 6 carbon atoms, such as methyl groups, ethyl groups, propyl groups, and phenyl groups, with methyl groups being particularly preferred.

[0167] Furthermore, hydrophilic groups include, for example, hydroxyl groups, sulfonic acid groups, carboxyl groups, or carbonyl groups, with hydroxyl groups being particularly preferred. While hydrophilic groups may be included as functional groups, it is preferable that they are not included from the viewpoint of imparting hydrophobicity to the silane coupling agent (D).

[0168] Furthermore, hydrolyzable groups include alkoxy groups such as methoxy groups and ethoxy groups, chloro groups, or silazane groups, and among these, silazane groups are preferred due to their high reactivity with silica particles (C). Note that those having a silazane group as a hydrolyzable group are, due to their structural characteristics, (Y in formula (4) above. n It will have two -Si-) structures.

[0169] Specific examples of the silane coupling agent (D) represented by formula (4) above include, for example, alkoxysilanes such as methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, and decyltrimethoxysilane, which have a hydrophobic group as a functional group; chlorosilanes such as methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, and phenyltrichlorosilane; and hexamethyldisilazane, which have a hydrophobic group as a functional group. Examples of materials having a vinyl group include alkoxysilanes such as methacryloxypropyltriethoxysilane, methacryloxypropyltrimethoxysilane, methacryloxypropylmethyldiethoxysilane, methacryloxypropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and vinylmethyldimethoxysilane; chlorosilanes such as vinyltrichlorosilane and vinylmethyldichlorosilane; and divinyltetramethyldisilazane. Among these, considering the above description, hexamethyldisilazane is particularly preferred as the material having a hydrophobic group, and divinyltetramethyldisilazane is preferred as the material having a vinyl group.

[0170] In this embodiment, the lower limit of the silane coupling agent (D) content is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, based on 100 parts by weight of the total amount of vinyl group-containing organopolysiloxane (A). The upper limit of the silane coupling agent (D) content is preferably 100% by mass or less, more preferably 80% by mass or less, and even more preferably 40% by mass or less, based on 100 parts by weight of the total amount of vinyl group-containing organopolysiloxane (A). By setting the content of the silane coupling agent (D) above the lower limit, the overall mechanical strength of the silicone rubber can be improved when silica particles (C) are used. Furthermore, by setting the content of the silane coupling agent (D) below the upper limit, the silicone rubber can have appropriate mechanical properties.

[0171] <<Platinum or platinum compound (E)>> The silicone rubber-based curable composition of this embodiment may contain platinum or a platinum compound (E). Platinum or platinum compound (E) is a catalytic component that acts as a catalyst during hardening. The amount of platinum or platinum compound (E) added is the catalytic amount.

[0172] As platinum or a platinum compound (E), known substances can be used, such as platinum black, platinum supported on silica or carbon black, chloroplatinic acid or an alcoholic solution of chloroplatinic acid, a complex salt of chloroplatinic acid and an olefin, or a complex salt of chloroplatinic acid and a vinylsiloxane.

[0173] Platinum or platinum compound (E) may be used alone or in combination of two or more types.

[0174] <<Water(F)>> Furthermore, the silicone rubber-based curable composition of this embodiment may also contain water (F) in addition to the above components (A) to (E).

[0175] Water (F) functions as a dispersion medium that disperses the various components contained in the silicone rubber curable composition, and also contributes to the reaction between silica particles (C) and the silane coupling agent (D). Therefore, the silica particles (C) and the silane coupling agent (D) can be more reliably linked to each other in the silicone rubber, resulting in uniform properties overall.

[0176] Furthermore, if water (F) is included, its content can be set as appropriate, but specifically, it is preferably in the range of 10 to 100 parts by weight, and more preferably in the range of 30 to 70 parts by weight, per 100 parts by weight of the silane coupling agent (D). This allows the reaction between the silane coupling agent (D) and the silica particles (C) to proceed more reliably.

[0177] (Other ingredients) Furthermore, the silicone rubber-based curable composition of this embodiment may further contain other components in addition to the components (A) to (F) described above. Examples of these other components include inorganic fillers other than silica particles (C), such as diatomaceous earth, iron oxide, zinc oxide, titanium oxide, barium oxide, magnesium oxide, cerium oxide, calcium carbonate, magnesium carbonate, zinc carbonate, glass wool, and mica; additives such as reaction inhibitors, dispersants, pigments, dyes, antistatic agents, antioxidants, flame retardants, and thermal conductivity enhancers.

[0178] In a silicone rubber-based curable composition, the proportion of each component is not particularly limited, but for example, it can be set as follows.

[0179] In this embodiment, the upper limit of the silica particle (C) content may be, for example, 60 parts by weight or less, preferably 50 parts by weight or less, and more preferably 40 parts by weight or less, per 100 parts by weight of the total amount of vinyl group-containing organopolysiloxane (A). This allows for a balance of mechanical strengths such as hardness and tensile strength. The lower limit of the silica particle (C) content is not particularly limited, but may be, for example, 10 parts by weight or more, per 100 parts by weight of the total amount of vinyl group-containing organopolysiloxane (A).

[0180] The silane coupling agent (D) is preferably present in an amount of 5 to 100 parts by weight, and more preferably 5 to 40 parts by weight, per 100 parts by weight of the vinyl group-containing organopolysiloxane (A). This ensures that the dispersibility of silica particles (C) in the silicone rubber-based curable composition is reliably improved.

[0181] The content of organohydrogenpolysiloxane (B) is preferably, for example, 0.5 parts by weight to 20 parts by weight, and more preferably 0.8 parts by weight to 15 parts by weight, based on 100 parts by weight of the total amount of vinyl group-containing organopolysiloxane (A), silica particles (C), and silane coupling agent (D). A content of (B) within the above range may enable a more effective curing reaction.

[0182] The content of platinum or platinum compound (E) represents the catalytic amount and can be set as appropriate, but specifically, it is the amount such that the platinum group metal in this component is 0.01 to 1000 ppm by weight relative to the total amount of vinyl group-containing organopolysiloxane (A), silica particles (C), and silane coupling agent (D), preferably 0.1 to 500 ppm. By setting the content of platinum or platinum compound (E) to above the lower limit, the resulting silicone rubber composition can be sufficiently cured. By setting the content of platinum or platinum compound (E) to below the upper limit, the curing speed of the resulting silicone rubber composition can be improved.

[0183] Furthermore, if water (F) is included, its content can be set as appropriate, but specifically, it is preferably in the range of 10 to 100 parts by weight, and more preferably in the range of 30 to 70 parts by weight, per 100 parts by weight of the silane coupling agent (D). This allows the reaction between the silane coupling agent (D) and the silica particles (C) to proceed more reliably.

[0184] In this embodiment, the hardness, tensile strength, elongation at break, and tear strength can be controlled by appropriately selecting, for example, the type and amount of each component contained in the silicone rubber curable composition, the method of preparing the silicone rubber curable composition, etc. Among these, for example, appropriately controlling the type and blending ratio of the resin constituting the silicone rubber, the crosslinking density and crosslinking structure of the resin, improving the blending ratio of the inorganic filler and the bonding of the inorganic filler to the rubber, using a first vinyl group-containing linear organopolysiloxane (A1-1) with a vinyl group content of 0.4 mol% or less, using a silane coupling agent having vinyl groups, and appropriately adjusting the silica particle (C) content and the silane coupling agent content are examples of factors that can bring the hardness, tensile strength, elongation at break, and tear strength into desired numerical ranges.

[0185] <Method for manufacturing silicone rubber> Next, the method for manufacturing the silicone rubber of this embodiment will be described. The method for producing silicone rubber according to this embodiment involves preparing a silicone rubber-based curable composition and curing this silicone rubber-based curable composition to obtain silicone rubber. The details are explained below.

[0186] First, the components of the silicone rubber curable composition are uniformly mixed using any kneading device to prepare the silicone rubber curable composition.

[0187] [1] For example, a predetermined amount of vinyl group-containing organopolysiloxane (A), silica particles (C), and a silane coupling agent (D) are weighed out, and then kneaded using any kneading device to obtain a kneaded product containing these components (A), (C), and (D).

[0188] It is preferable to obtain this compound by first kneading a vinyl group-containing organopolysiloxane (A) and a silane coupling agent (D), and then kneading (mixing) silica particles (C). This further improves the dispersibility of silica particles (C) in the vinyl group-containing organopolysiloxane (A).

[0189] Furthermore, when obtaining this mixture, water (F) may be added to the mixture of components (A), (C), and (D) as needed. This allows the reaction between the silane coupling agent (D) and the silica particles (C) to proceed more reliably.

[0190] Furthermore, it is preferable that the kneading of each component (A), (C), and (D) proceeds through a first step of heating at a first temperature and a second step of heating at a second temperature. This allows the surface of the silica particles (C) to be surface-treated with the coupling agent (D) in the first step, and ensures that by-products generated by the reaction between the silica particles (C) and the coupling agent (D) are reliably removed from the kneaded mixture in the second step. Subsequently, if necessary, component (A) may be added to the resulting kneaded mixture and kneaded further. This improves the compatibility of the components in the kneaded mixture.

[0191] The first temperature is preferably, for example, around 40 to 120°C, and more preferably, around 60 to 90°C. The second temperature is preferably, for example, around 130 to 210°C, and more preferably, around 160 to 180°C.

[0192] Furthermore, the atmosphere in the first step is preferably an inert atmosphere such as a nitrogen atmosphere, and the atmosphere in the second step is preferably a reduced pressure atmosphere.

[0193] Furthermore, the duration of the first step is preferably about 0.3 to 1.5 hours, and more preferably about 0.5 to 1.2 hours. The duration of the second step is preferably about 0.7 to 3.0 hours, and more preferably about 1.0 to 2.0 hours.

[0194] By setting the conditions for the first and second steps as described above, the aforementioned effects can be obtained more significantly.

[0195] [2] Next, predetermined amounts of organohydrogenpolysiloxane (B) and platinum or a platinum compound (E) are weighed out, and then, using any kneading apparatus, components (B) and (E) are kneaded into the mixture prepared in step [1] above to obtain a silicone rubber curable composition. The obtained silicone rubber curable composition may be a paste containing a solvent.

[0196] Furthermore, when kneading each of these components (B) and (E), it is preferable to first knead the kneaded product prepared in step [1] with the organohydrogenpolysiloxane (B), and the kneaded product prepared in step [1] with platinum or a platinum compound (E), and then knead each of these kneaded products. This ensures that each of the components (A) to (E) can be reliably dispersed in the silicone rubber-based curable composition without allowing the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) to proceed.

[0197] The temperature at which components (B) and (E) are kneaded is preferably, as the roll setting temperature, around 10 to 70°C, and more preferably around 25 to 30°C.

[0198] Furthermore, the mixing time is preferably, for example, 5 minutes to 1 hour, and more preferably 10 to 40 minutes.

[0199] In steps [1] and [2] described above, by keeping the temperature within the above range, the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) can be more effectively prevented or suppressed. Furthermore, in steps [1] and [2] described above, by keeping the kneading time within the above range, each component (A) to (E) can be more reliably dispersed in the silicone rubber-based curable composition.

[0200] The kneading equipment used in each of the processes [1] and [2] is not particularly limited, but for example, a kneader, a two-roll mixer, a Banbury mixer (continuous kneader), a pressure kneader, etc., can be used.

[0201] Furthermore, in step [2], a reaction inhibitor such as 1-ethynylcyclohexanol may be added to the kneaded mixture. This makes it possible to more effectively prevent or suppress the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B), even if the temperature of the kneaded mixture is set to a relatively high temperature.

[0202] [3] Next, silicone rubber is formed by curing the silicone rubber-based curable composition.

[0203] In this embodiment, the curing process of the silicone rubber-based curable resin composition is carried out, for example, by heating at 100 to 250°C for 1 to 30 minutes (primary curing), followed by post-baking at 200°C for 1 to 4 hours (secondary curing).

[0204] By going through the above process, silicone rubber consisting of a cured product of a silicone rubber-based curable resin composition is obtained.

[0205] [3] Next, an insulating paste can be obtained by dissolving the silicone rubber-based curable composition obtained in step [2] in a solvent. Furthermore, [3] Next, a conductive paste can be obtained by dissolving the silicone rubber-based curable composition obtained in step [2] in a solvent and adding a conductive filler.

[0206] (solvent) Conductive pastes and insulating pastes contain solvents. Various known solvents can be used as the solvent, but for example, high-boiling point solvents may be included. These may be used individually or in combination of two or more.

[0207] The lower limit of the boiling point of the high-boiling-point solvent is, for example, 100°C or higher, preferably 130°C or higher, and more preferably 150°C or higher. This improves the printing stability, such as in screen printing. On the other hand, the upper limit of the boiling point of the high-boiling-point solvent is not particularly limited, but may be, for example, 300°C or lower, 290°C or lower, or 280°C or lower. This suppresses excessive thermal history during wiring formation, thereby preventing damage to the substrate and maintaining the shape of the wiring formed with conductive paste in good condition.

[0208] Furthermore, the solvent can be appropriately selected from the viewpoint of its solubility and boiling point for the silicone rubber-based curable resin composition, but for example, it may include aliphatic hydrocarbons having 5 to 20 carbon atoms, preferably aliphatic hydrocarbons having 8 to 18 carbon atoms, and more preferably aliphatic hydrocarbons having 10 to 15 carbon atoms.

[0209] Examples of solvents include aliphatic hydrocarbons such as pentane, hexane, cyclohexane, heptane, methylcyclohexane, ethylcyclohexane, octane, decane, dodecane, and tetradecane; aromatic hydrocarbons such as benzene, toluene, ethylbenzene, xylene, mesitylene, trifluoromethylbenzene, and benzotrifluoride; and diethyl ether, diisopropyl ether, dibutyl ether, cyclopentyl methyl ether, cyclopentyl ethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, and diethylene glycol dimethyl ether. Examples include ethers such as chol monobutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol methyl-n-propyl ether, 1,4-dioxane, 1,3-dioxane, and tetrahydrofuran; haloalkanes such as dichloromethane, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,1-trichloroethane, and 1,1,2-trichloroethane; carboxylic acid amides such as N,N-dimethylformamide and N,N-dimethylacetamide; sulfoxides such as dimethyl sulfoxide and diethyl sulfoxide; and esters such as diethyl carbonate. These may be used individually or in combination of two or more. The solvent used here should be appropriately selected from among solvents that can uniformly dissolve or disperse the components of the conductive paste described above.

[0210] The above solvent has a polarity term (δ) in the Hansen solubility parameter. p The upper limit of ) is, for example, 10 MPa 1 / 2 The following is preferred: 7 MPa 1 / 2 The following, and more preferably 5.5 MPa 1 / 2 The following first solvent may be included. This improves the dispersibility and solubility of the silicone rubber-based curable resin composition in the paste. The above polarity term (δ) of this first solvent p The lower limit of ) is not particularly limited, but for example, 0 Pa 1 / 2 That's fine too.

[0211] The hydrogen bonding term (δ) of the Hansen solubility parameter in the first solvent described above. h The upper limit of ) is, for example, 20 MPa 1 / 2 The following, preferably 10 MPa 1 / 2 The following is more preferable: 7 MPa 1 / 2 The following is the result. This makes it possible to improve the dispersibility and solubility of the silicone rubber-based curable resin composition in the paste. The above hydrogen bonding term (δ) of this first solvent h The lower limit of ) is not particularly limited, but for example, 0 Pa 1 / 2 That's fine too.

[0212] Hansen's solubility parameter (HSP) is an index that represents the solubility of one substance, indicating how much of it dissolves in another substance. HSP represents solubility as a three-dimensional vector. This three-dimensional vector typically includes a dispersion term (δ). d ), polarity term (δ p ), hydrogen bond term (δ h It can be represented as follows. And if the vectors are similar, it can be judged that they have high solubility. The similarity of the vectors can be judged by the distance of the Hansen solubility parameters (HSP distance).

[0213] The Hansen solubility parameters (HSP values) used in this specification can be calculated using software called HSPiP (Hansen Solubility Parameters in Practice). HSPiP, developed by Hansen and Abbott, includes a function to calculate HSP distances and a database containing Hansen parameters for various resins and solvents or non-solvents. The solubility of each resin in pure solvents and mixed solvents of good and poor solvents is investigated, and the results are entered into HSPiP software to calculate D: dispersion term, P: polarity term, H: hydrogen bonding term, and R0: solubility sphere radius.

[0214] As the solvent in this embodiment, for example, one can be selected that has a small difference in HSP distance, polarity term, and hydrogen bonding term between the elastomer or the constituent units of the elastomer and the solvent.

[0215] The lower limit of viscosity of conductive paste and / or insulating paste measured at room temperature (25°C) with a shear rate of 20 [1 / s] is, for example, 1 Pa·s or more, preferably 5 Pa·s or more, and more preferably 10 Pa·s or more. This improves film formation and enhances shape retention even when forming thick films. On the other hand, the upper limit of viscosity of conductive paste and / or insulating paste at room temperature (25°C) is, for example, 100 Pa·s or less, preferably 90 Pa·s or less, and more preferably 80 Pa·s or less. This improves printability of the paste.

[0216] At room temperature of 25°C, the viscosity measured at a shear rate of 1 [1 / s] is defined as η1, and the viscosity measured at a shear rate of 5 [1 / s] is defined as η5. The thixotropy index is defined as the viscosity ratio (η1 / η5). In this case, the lower limit of the thixotropy of the conductive paste and / or insulating paste is, for example, 1.0 or higher, preferably 1.1 or higher, and more preferably 1.2 or higher. This allows the shape of the wiring obtained by the printing method to be stably maintained. On the other hand, the upper limit of the thixotropy of the conductive paste and / or insulating paste is, for example, 3.0 or lower, preferably 2.5 or lower, and more preferably 2.0 or lower. This improves the printability of the paste.

[0217] 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.

[0218] (Conductive filler) As the conductive filler, known conductive materials 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 powders 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, due to high conductivity and high availability. In addition, these metal powders (G) coated with other metals can also be used.

[0219] In this embodiment, the shape of the metal powder (G) is not limited, and conventionally used ones such as dendritic, spherical, flaky, etc. can be used. Among these, flaky metal powder (G) may be used.

[0220] 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 the range to this extent, the silicone rubber can exhibit appropriate conductivity. The particle size of the metal powder (G) can be defined, for example, by observing conductive paste or silicone rubber molded using conductive paste with a transmission electron microscope, performing image analysis, and then determining the average value of 200 arbitrarily selected metal powders.

[0221] The content of conductive filler in the conductive paste is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more, based on the total content of the conductive paste. Furthermore, the content of conductive filler in the conductive paste is preferably 85% by mass or less, more preferably 75% by mass or less, and even more preferably 65% ​​by mass or less, based on the total content of the conductive paste. By setting the conductive filler content above the lower limit, the silicone rubber can acquire appropriate conductivity. Furthermore, by setting the conductive filler content below the upper limit, the silicone rubber can acquire appropriate flexibility.

[0222] The content of the silicone rubber-based curable composition in the conductive paste is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, based on 100% by mass of the conductive paste. Furthermore, the content of the silicone rubber-based curable composition in the conductive paste is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, based on 100% by mass of the conductive paste. By setting the content of the silicone rubber-based curable composition to be above the lower limit, the silicone rubber can have appropriate flexibility. Furthermore, by setting the content of the silicone rubber-based curable composition to be below the upper limit, the mechanical strength of the silicone rubber can be improved.

[0223] The lower limit of the content of the silica particles (C) in the conductive paste can be, for example, 1% by mass or more, preferably 3% by mass or more, and more preferably 4% by mass or more, based on 100% by mass of the total amount of the silica particles (C) and the conductive filler. 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, and more preferably 10% by mass or less, based on 100% by mass of the total amount of the silica particles (C) and the conductive filler. Thereby, the balance between the stretch electrical characteristics and the mechanical strength in the silicone rubber can be achieved.

[0224] 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, and 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, and 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.

[0225] 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, and more preferably 4% by mass or more, based on 100% by mass of the total amount of the silica particles (C) and the conductive filler. 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, and more preferably 10% by mass or less, based on 100% by mass of the total amount of the silica particles (C) and the conductive filler. Thereby, the balance between the stretch electrical characteristics and the mechanical strength in the silicone rubber can be achieved.

[0226] As described above, the embodiments of the present invention have been described, but these are 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 that can achieve the object of the present invention are included in the present invention.

Example

[0227] 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.

[0228] The raw material components shown in Table 1 are shown below. (A1-1): First vinyl group-containing linear organopolysiloxane: Vinyl group-containing dimethylpolysiloxane synthesized by the following synthesis scheme 1 (structure represented by the above formula (1-1)) (A1-2): Second vinyl group-containing linear organopolysiloxane: Vinyl group-containing dimethylpolysiloxane synthesized by the following synthesis scheme 2 (structure represented by the above formula (1-1) where R 1 and R 2 are vinyl groups)

[0229] (Organohydrogenpolysiloxane (B)) (B-1): Organohydrogenpolysiloxane: manufactured by Momentive, "TC-25D"

[0230] (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"

[0231] (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)"

[0232] (Platinum or platinum compound (E)) (E-1): Platinum compound (manufactured by Momentive, trade name "TC-25A")

[0233] (Water (F)) (F): Pure water

[0234] (Metal powder (G)) (G1): Silver powder, manufactured by Tokushukagaku Kenkyusho, trade name "TC-101", median diameter d 50 : 8.0 μm, aspect ratio 16.4, average major diameter 4.6 μm

[0235] (Synthesis of vinyl group-containing organopolysiloxane (A)) [Synthesis Scheme 1: Synthesis of the first vinyl group-containing linear organopolysiloxane (A1-1)] The first vinyl group-containing linear organopolysiloxane (A1-1) was synthesized according to the following formula (5). 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 cooling tube and a stirring blade under Ar gas substitution, and the temperature was raised 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 further stirred 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 the 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%.

[0236] [Chemical formula]

[0237] [Synthesis Scheme 2: Synthesis of the second vinyl group-containing linear organopolysiloxane (A1-2)] In the synthesis process of (A1-1) above, except for using 0.86 g (2.5 mmol) of 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane 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) in the same manner as the synthesis process of (A1-1) (Mn = 2.3×10 5 , Mw = 5.0×10 5 ). Also, the vinyl group content calculated by 1H-NMR spectrum measurement was 0.93 mol%.

[0238] [Chemical formula]

[0239] (Preparation of silicone rubber-based curable composition) The silicone rubber-based curable compositions of Samples 1 and 2 were prepared according to the following procedure. First, a mixture of 90% vinyl group-containing organopolysiloxane (A), silane coupling agent (D), and water (F) was kneaded in advance at the ratios shown in Table 1 below, and then silica particles (C) were added to the mixture and kneaded further to obtain a kneaded product (silicone rubber compound). Here, the kneading after adding silica particles (C) was carried out through a first step of kneading for 1 hour under nitrogen atmosphere at 60 - 90 °C for the coupling reaction and a second step of kneading for 2 hours under reduced pressure atmosphere at 160 - 180 °C for removing by-products (ammonia), and then cooled, and the remaining 10% vinyl group-containing organopolysiloxane (A) was added in two portions and kneaded for 20 minutes. Next, organohydrogenpolysiloxane (B), platinum, or a platinum compound (E) were added to 100 parts by weight of the resulting mixture (silicone rubber compound) in the proportions shown in Table 2 below, and the mixture was kneaded with a roll to obtain a silicone rubber-based curable composition.

[0240] (Preparation of conductive paste) The obtained 15.3 parts by weight of the silicone rubber-based curable composition of Sample 1 was immersed in 34.8 parts by weight of decane (solvent), then stirred with a rotating / revolving mixer, and after adding 65.2 parts by weight of metal powder (G1), the mixture was further kneaded with the rotating / revolving mixer to obtain a conductive paste with a total content of 69.8% by weight of the silicone rubber-based curable composition and metal powder (G1).

[0241] (Preparation of insulating paste) The obtained 15.3 parts by weight of the silicone rubber-based curable composition of Sample 2 was immersed in 32.5 parts by weight of decane (solvent), and then stirred with a rotating / revolving mixer to obtain an insulating paste.

[0242] [Table 1]

[0243] (Fabrication of flexible sheet electrodes) A flexible base material (polyester knitted fabric, weight 130g / m²) measuring 7cm x 7cm x 0.4mmth thick is applied to the flat surface of a stainless steel substrate. 2 A ) was placed, and then a mask (made of polyethylene terephthalate) with one 5cm x 5cm opening and a thickness of 125μm was placed on the surface of the flexible substrate. Next, the insulating paste described above was applied to the opening of the mask, and squeegee printing was performed using a glass plate in a printing direction perpendicular to the fiber grain, based on the printing conditions shown in Table 2. After that, the mask was removed and dried at 140°C for 20 minutes. Subsequently, squeegee printing was performed similarly using conductive paste, based on the printing conditions shown in Table 2. However, in Comparative Example 1, squeegee printing was performed using only conductive paste. Next, the mask was removed, and the printed insulating paste and conductive paste were cured at 180°C for 2 hours to create a flexible sheet electrode with an elastomer electrode layer provided on a flexible substrate.

[0244] In Table 2, the amount of insulating elastomer layer (cured product of insulating paste) and conductive elastomer layer (cured product of conductive paste) attached was calculated by subtracting the weight of the flexible substrate, which was measured in advance, from the weight of the flexible sheet electrode. Furthermore, the flexible sheet electrode was cut in the lamination direction, and one of the cross-sections was observed with an electron microscope to obtain a 1 mm × 1 mm SEM image. Based on the SEM image, the thickness of the impregnated layer (T1) in which the elastomer electrode layer is impregnated into the flexible substrate, the thickness of the lamination where the elastomer electrode layer is not impregnated into the flexible substrate (T2), the thickness of the conductive elastomer layer in the lamination (T2'), and the thickness of the flexible substrate (T3) were determined. Specifically, a cross-sectional SEM image A of the flexible substrate only was obtained in the region where the conductive elastomer layer was not formed, and the substrate thickness (T3) was measured from that SEM image A. A cross-sectional SEM image B of the flexible sheet electrode was obtained in the region where the conductive elastomer layer was formed. The total thickness (X) of the flexible sheet electrode was measured from this SEM image B, and the laminate thickness (T2) was calculated by subtracting the substrate thickness (T3) from the total thickness (X). From the cross-sectional SEM image B of the flexible sheet electrode, the length from the boundary where the insulating or conductive paste is impregnated to the boundary between the substrate and the laminate was measured as the impregnation thickness (T1).

[0245] Furthermore, we examined SEM images of a 1mm x 1mm area on the surface of the conductive elastomer layer. As a result, it was found that in Examples 1 to 5, the conductive elastomer layer in the above region covered the entire surface of the flexible substrate, and that this surface was composed of a smooth surface that was smoother than the surface structure of the flexible substrate. In Comparative Example 1, on the other hand, it was found that the conductive elastomer layer in the above region had portions that adhered to the surface structure of the flexible substrate, and did not form a single surface as a whole.

[0246] [Table 2]

[0247] The following items were evaluated for the obtained flexible sheet electrodes. The results are shown in Table 2.

[0248] (Surface resistance value rate) The printed portion of the obtained flexible sheet electrode was cut into 1cm x 1cm pieces to prepare a sample. Using that sample, the surface resistivity (Ω / □) of the conductive elastomer layer on the surface side of the elastomer electrode layer was measured at 25°C in an unextended state, with a probe applied to the center and the four-probe method used.

[0249] (Washing resistance) The resulting flexible sheet electrodes were subjected to the following washing test. 1. The flexible sheet electrode was stretched and contracted 300 times in both the vertical and horizontal directions to 100%. 2. Put neutral detergent and water into a beaker, immerse the flexible sheet electrode that has been treated in step 1, and stir for 24 hours. 3. Pour water into a beaker, immerse the flexible sheet electrode that has been treated in step 2, stir for 10 minutes, and rinse off the detergent. 4. Dry in an oven at 90°C for 30 minutes. The above steps 1-4 were repeated 50 times. For the flexible sheet electrodes of each example and comparative example after the washing test described above, the surface resistivity of the conductive elastomer layer was measured based on the measurement conditions described above. Furthermore, in each example, it was confirmed that no cracks occurred in the conductive elastomer layer, nor did delamination occur between it and the flexible substrate, and that the initial state was maintained. On the other hand, in Comparative Example 1, cracks were observed in the conductive elastomer layer and delamination was observed between it and the flexible substrate. Therefore, the wash resistance of the flexible sheet electrodes in Examples 1-5 was evaluated as good (○), while that of Comparative Example 1 was evaluated as poor (×). The results are shown in Table 2.

[0250] (Bioelectric potential measurement) In each of the obtained examples of flexible sheet electrodes, an external connector (a metal male snap button) was attached to the other side of the flexible substrate opposite to the side on which the conductive elastomer layer was formed, and the external connector and the conductive elastomer layer were electrically connected to obtain a wearable bioelectrode. Three wearable bioelectrodes were prepared, and the external connection points of each of the three wearable bioelectrodes were connected to a BITalino (manufactured by Plux) via electrode cables with connectors (female snap buttons) and ECG sensors (manufactured by Plux), thereby creating an electrocardiogram measurement device (biosensor). Flexible sheet electrodes, each attached to one side of three wearable bioelectrodes, were placed directly on the subject's skin, and the subject's electrocardiogram was measured using a three-lead method (measurement point, reference, and body ground). The results above confirm that electrocardiogram waveforms can be monitored by using wearable bioelectrodes equipped with flexible sheet electrodes as described in each embodiment.

[0251] The flexible sheet electrodes of Examples 1 to 5 showed superior conductivity after washing and washing resistance compared to Comparative Example 1. These flexible sheet electrodes from each example can be suitably used in wearable bioelectrodes. [Explanation of symbols]

[0252] 1. Flexible sheet electrode 2. Elastomer electrode layer 10 Flexible base material 11 one side 12 Main unit 13 Other side 14. Expansion section 20 Conductive elastomer layer 20a Conductive elastomer layer 20b Conductive elastomer layer 21 Impregnated layer 22 one side 23 layers 24 Stretchable wiring 26 Connection part 30 External connection section 32 Mounting plate 34 Mounting pins 50 protective layer 52 Insulating protective layer 60 Insulating elastomer layer 60a insulating elastomer layer 60b Insulating elastomer layer 100 Wearable Bioelectrodes 200 biosensors 210 connector 220 Cable 230 Sensor Modules 240 Computers

Claims

1. Flexible substrate and The flexible substrate comprises an elastomer electrode layer provided on the flexible substrate, The elastomer electrode layer is Formed on the inside of the aforementioned flexible substrate, the impregnation layer includes an insulating elastomer layer, Formed on the outside of the aforementioned flexible substrate, the laminate includes a conductive elastomer layer, Having, Flexible sheet electrode.

2. A flexible sheet electrode according to claim 1, A flexible sheet electrode is configured such that when the thickness of the impregnated layer is T1 and the thickness of the laminate is T2, T1 and T2 satisfy 0.1 ≤ T1 / T2 ≤ 100.

3. A flexible sheet electrode according to claim 1 or 2, A flexible sheet electrode is configured such that when the thickness of the laminate is T2 and the thickness of the conductive elastomer layer in the laminate is T2', T2 and T2' satisfy 0.02 ≤ T2' / T2 ≤ 1.

4. A flexible sheet electrode according to any one of claims 1 to 3, A flexible sheet electrode is configured such that when the thickness of the impregnated layer is T1 and the thickness of the flexible substrate is T3, T1 and T3 satisfy 0.01 ≤ T1 / T3 ≤ 1.

5. A flexible sheet electrode according to any one of claims 1 to 4, The amount of the conductive elastomer layer attached is 10 mg / cm². ２ 100mg / cm or more ２ The following is a flexible sheet electrode.

6. A flexible sheet electrode according to any one of claims 1 to 5, The amount of the insulating elastomer layer attached is 1 mg / cm². ２ 40mg / cm or more ２ The following is a flexible sheet electrode.

7. A flexible sheet electrode according to any one of claims 1 to 6, A flexible sheet electrode in which the laminate includes another insulating elastomer layer inside the conductive elastomer layer.

8. A flexible sheet electrode according to claim 7, A flexible sheet electrode in which the outermost layer of the laminate is composed of the conductive elastomer layer.

9. A flexible sheet electrode according to any one of claims 1 to 8, A flexible sheet electrode wherein the conductive elastomer layer includes a conductive filler and a non-conductive filler.

10. A flexible sheet electrode according to claim 9, A flexible sheet electrode in which the conductive filler contains flake-shaped silver powder.

11. A flexible sheet electrode according to claim 9 or 10, A flexible sheet electrode in which the nonconductive filler contains silica particles.

12. A flexible sheet electrode according to any one of claims 9 to 11, A flexible sheet electrode wherein the content of the conductive filler in the conductive elastomer layer is 50% by mass or more and 90% by mass or less.

13. A flexible sheet electrode according to any one of claims 1 to 12, A flexible sheet electrode in which the insulating elastomer layer and / or the conductive elastomer layer contains silicone rubber.

14. A flexible sheet electrode according to any one of claims 1 to 13, A flexible sheet electrode wherein the flexible substrate is a woven or knitted fabric.

15. A wearable bioelectrode comprising a flexible sheet electrode according to any one of claims 1 to 14.

16. A biosensor comprising a wearable bioelectrode as described in claim 15.

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