Substrate sheet with fiber electrodes

Abstract

The present invention aims to provide a base sheet with a fiber electrode that has a conductive performance that enables sufficient acquisition of biosignals, which are weak electrical signals unconsciously emitted from the body, and that enables electrical stimulation to be applied by inputting electrical signals, and that can stably conduct electrical signals when performing various actions, and further, that is resistant to deterioration or change in conductive performance even with repeated use, and a product that includes the base sheet with a fiber electrode. The base sheet with a fiber electrode of the present invention includes a base sheet and a fiber electrode constituted by an embroidered portion containing conductive thread, and satisfies all of the following characteristics (1) to (4). (1) The size of the embroidered area on the surface of the fiber electrode is 0.1 cm 2 That's all. (2) The conductive yarn is a composite yarn containing organic fibers and metal fibers. (3) The metal fiber content in the embroidery is 0.001 to 0.1 g / cm 2 It is. (4) The surface resistance of the fiber electrode is 15 Ω / cm 2 The following is the result.

Description

[Technical field]

[0001] The present invention relates to a base sheet with a fiber electrode, which includes a base sheet and a fiber electrode constituted by an embroidered portion containing conductive thread. [Background technology]

[0002] In recent years, there has been a demand for electrodes that can collect biosignals, which are weak electrical signals that are unconsciously emitted from the body. Biosignals generally refer to signals emitted from the body due to biological phenomena such as heart rate, brain waves, pulse, breathing, sweating, and exercise. Accumulating and analyzing such biosignals can be used not only for health management, but also for efficient sports training and the medical field. On the other hand, various research has been conducted on electrodes that input electrical signals to living organisms such as muscles and nerves and provide electrical stimulation, as opposed to acquiring biosignals. Surface electrode types that are directly attached to the skin are often used in home low-frequency therapeutic devices.

[0003] Electrodes that can reliably obtain weak electrical signals and / or input electrical signals or impart electrical stimulation are required to have low electrical resistance, to provide a stable and appropriate sense of electrical stimulation, to be comfortable even when used for long periods of time because they come into direct contact with the living body or skin, and to be easy to handle. To date, electrodes that use thin metal plates, gel electrodes, and rubber electrodes, as well as textile-shaped electrodes in which conductive threads are contained in some of the fibers that make up the woven or knitted fabric, have been proposed.

[0004] Among these, knitted and woven forms have been proposed as textile electrodes. In addition, the conductive threads used include fibers containing fine particles such as carbon, metal-coated fibers with a metal such as copper coated on the fiber surface, a plurality of twisted metal threads made of aluminum or tungsten, and a composite of these metal threads and organic fibers. However, knitted fabrics have a large elasticity and are prone to fluctuations in electrical resistance, and woven fabrics have a stable electrical resistance but suffer from a large loss of conductive thread during production, resulting in poor productivity.

[0005] Therefore, as a fiber electrode using conductive thread in a form other than knitted fabric or woven fabric, for example, Patent Document 1 proposes an embroidered electrode formed by embroidering conductive thread to make the electrode soft to the touch and highly flexible. However, the conductive thread described in Patent Document 1 is a silver-plated polyamide fiber, and the surface resistance value is not sufficiently low. Also, clothing with embroidered electrodes has been proposed, and it is described as being "suitable for performing electrocardiogram (ECG) measurements of humans in a walking state." However, since silver-plated polyamide fiber is used, there is a drawback in that the silver plating on the fiber surface peels off with repeated use, and the conductive performance deteriorates with long-term use. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 4787161 Summary of the Invention [Problem to be solved by the invention]

[0007] Considering convenience in daily life, it is preferable to attach embroidered electrodes to clothing in order to acquire biosignals, which are weak electrical signals, or to input electrical signals and apply electrical stimulation. In order to acquire biosignals and / or provide electrical stimulation to healthy individuals, it is necessary to constantly conduct electrical signals stably, assuming all kinds of movements. Naturally, such clothing is used repeatedly, and it is required that the conductive performance does not deteriorate or change even after repeated use.

[0008] As described above, a fiber electrode that has the conductive performance to fully acquire biosignals, which are weak electrical signals, and to input electrical signals to provide electrical stimulation, and that can stably conduct electrical signals when performing various operations, and further whose conductive performance is unlikely to deteriorate or change even with repeated use, and a textile product having such a fiber electrode have not yet been proposed.

[0009] The present invention aims to provide a base material sheet with a fiber electrode that has conductive performance that enables it to fully acquire biosignals, which are weak electrical signals that are unconsciously emitted from the body, and to apply electrical stimulation by inputting electrical signals, and whose conductive performance is unlikely to deteriorate or change even with repeated use, and a product that includes the base material sheet with a fiber electrode. [Means for solving the problem]

[0010] The inventors discovered that the above-mentioned problems can be solved by using a composite yarn containing organic fibers and metal fibers as a conductive yarn, forming a fiber electrode having an embroidered portion on a base sheet where the conductive yarn is stitched, and adjusting the size of the embroidered portion on the surface of the fiber electrode, the content of metal fibers contained in the embroidered portion, and the surface resistance value on the surface of the fiber electrode within specific ranges, and thus arrived at the present invention.

[0011] That is, the present invention provides the following aspects. <1> A base sheet with a fiber electrode comprising a base sheet and a fiber electrode constituted by an embroidered portion containing conductive thread, the base sheet with a fiber electrode satisfying all of the following characteristics (1) to (4). (1) The size of the embroidered area on the surface of the fiber electrode is 0.1 cm 2 That's all. (2) The conductive yarn is a composite yarn containing organic fibers and metal fibers. (3) The metal fiber content in the embroidery is 0.001 to 0.1 g / cm 2 It is. (4) The surface resistance of the fiber electrode is 15 Ω / cm 2 The following is the result. <2> The metal fibers contained in the conductive yarn have a diameter of 2 to 150 μm. <1> The substrate sheet with the fiber electrode according to claim 1 . <3> The absolute value of the change in surface resistance after 30 friction tests on the fiber electrode surface is 1Ω / cm 2 Below is the <1> or <2> The substrate sheet with the fiber electrode according to claim 1 . <4> The fiber electrodes have a dimensional retention rate of 85% or more after 50 washes. <1> ~ <3> 2. The substrate sheet with a fiber electrode according to claim 1 . <5> The thickness index T calculated by the following formula is 4.0 or less. <1> ~ <4> 2. The substrate sheet with a fiber electrode according to claim 1 . Thickness index T=(T2-T1) / T1 (T1: thickness of the base sheet with fiber electrodes, T2: maximum thickness of the base sheet with fiber electrodes when folded in half so that the fiber electrodes face each other and perpendicular to the embroidery direction of the conductive thread on which the fiber electrodes are embroidered) <6> The void ratio in the embroidery area is 18% or less. <1> ~ <5> 2. The substrate sheet with a fiber electrode according to claim 1 . <7> The embroidered portion has stitches in which conductive threads are arranged to cross each other. <1> ~ <6> 2. The substrate sheet with a fiber electrode according to claim 1 . <8> A water-absorbing agent is provided on the surface of the fiber electrode. <1> ~ <7> 2. The substrate sheet with a fiber electrode according to claim 1 . <9> <1> ~ <8> 2. A product having, at least in a part thereof, the substrate sheet with a fiber electrode according to claim 1. Effect of the Invention

[0012] The base sheet with fiber electrodes of the present invention has an embroidered portion formed on the base sheet and stitched with conductive thread that functions as an electrode and satisfies all of the above characteristics (1) to (4), and therefore has excellent conductive performance for fully acquiring biosignals, which are weak electrical signals unconsciously emitted from the body, and for inputting electrical signals to impart electrical stimulation, and can stably conduct electrical signals when performing various actions by making stable contact with the skin. Furthermore, the conductive performance of the base sheet with fiber electrodes of the present invention is unlikely to decrease or change even with repeated use.

[0013] Therefore, the base sheet with fiber electrode of the present invention is preferably used as a biological electrode, and by providing it on at least a part of a substrate, it can be used as a product that can acquire biological signals and / or impart electric signals or electric stimuli. Furthermore, when the base sheet with fiber electrode of the present invention is used as a part of clothing, it can be preferably used as clothing for health management, wear for efficient sports training, and also as a supporter for assisting walking. [Brief description of the drawings]

[0014] [Figure 1] 1 is a photograph in place of a drawing showing one embodiment of a substrate sheet with a fiber electrode of the present invention. [Diagram 2] FIG. 1 is an explanatory diagram showing the image analysis of a substrate sheet with a fiber electrode obtained in Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] <Base sheet with fiber electrodes> The substrate sheet with a fiber electrode of the present invention includes a substrate sheet and a fiber electrode constituted by an embroidered portion including a conductive thread. The substrate sheet with a fiber electrode of the present invention will be described in detail below.

[0016] [Base sheet] The substrate sheet in the present invention is not particularly limited as long as it can form a fiber electrode composed of an embroidered portion containing a conductive thread thereon, and examples thereof include woven fabrics, knitted fabrics, nonwoven fabrics, felt, rubber, resin sheets, films, and foam sheets. The substrate sheet is preferably one having an excessively large elongation characteristic, for example, a woven fabric, from the viewpoint of maintaining dimensional stability when stitching an embroidered portion thereon, or during use or washing of a product having a substrate sheet with a fiber electrode. In addition, it is also preferable to use a material having water retention for the substrate sheet from the viewpoint of further improving the conduction of electrical signals and increasing the moisture content around the fiber electrode. Examples of materials having water retention include materials with low water permeability such as rubber, films, and foam sheets; brushed woven fabrics, knitted fabrics, and nonwoven fabrics. The substrate sheet may be a single sheet, or may be a laminate in which one or more materials are layered.

[0017] When the base sheet is a woven fabric, the type of the woven fabric may be, for example, a plain weave, a twill weave, a satin weave, a pile weave, or a variation of these. When the base sheet is a knitted fabric, the type of the knitted fabric may be either a warp knitted fabric or a weft knitted fabric. Examples of the warp knitted fabric include denby knitting, cord knitting, and atlas knitting, and specific examples thereof include tricot half and tricot satin. Examples of the weft knitted fabric include plain knitting, rib knitting, purl knitting, and smooth knitting, and specific examples thereof include jersey, pique, and smooth.

[0018] When the base sheet is a nonwoven fabric, the nonwoven fabric may be obtained by any of the following methods: wet laying, chemical bonding, thermal bonding, needle punching, spun lace, stitch bonding, air laying, spun bonding, and melt blowing. When the base sheet is a felt, the felt may be, for example, a felt produced by fulling.

[0019] When the base sheet is a woven or knitted fabric, the fibers used in weaving or knitting may be filaments or spun yarns using staple fibers. Examples of the types of filaments and staple fibers include synthetic fibers such as polyester, nylon, vinylon, polyurethane, and polypropylene; vegetable fibers such as cotton, hemp, and bamboo; regenerated fibers such as viscose rayon, solvent-spun cellulose fibers, and lyocell; animal hair fibers such as sheep, cashmere, camel, angora, mohair, alpaca, mink, and seal; and modal fibers.

[0020] [Fiber electrode] The fiber electrode in the present invention is an electrode formed by embroidering the base sheet with conductive thread. The stitches that appear on the surface by embroidery are the stitches. In the present invention, the surface of the fiber electrode is the surface on which most of the stitches of the conductive thread are present. On the other hand, the surface on which the stitches of the lower thread appear is the back surface of the fiber electrode. The fiber electrode in the present invention is an electrode formed by forming an embroidered part with conductive thread on the base sheet, and is not an electrode in an embodiment in which the base sheet itself, such as a knitted fabric or woven fabric, contains conductive thread, that is, an electrode in an embodiment in which at least a part of the thread constituting the base sheet itself uses conductive thread. Therefore, the fiber electrode in the present invention does not stretch excessively itself and shows a stable surface resistance value. In addition, the fiber electrode in the present invention has conductive threads more densely and exposed on the surface of the fiber electrode compared to the back surface, so that it is possible to conduct electric signals more efficiently than an electrode in an embodiment in which conductive threads are used as threads constituting the base sheet itself, such as a knitted fabric or woven fabric.

[0021] The fiber electrode may be composed of only one embroidered part on one base sheet where a conductive thread is stitched, or may be composed of multiple embroidered parts. When the fiber electrode has multiple embroidered parts, the number is not limited and can be changed appropriately depending on the type of electrical signal to be collected or the application such as acquisition and / or input of electrical signals. In addition, the aspects and characteristic values ​​of the fiber electrode will be described below, and when the fiber electrode has multiple embroidered parts on the base sheet, it is preferable that each embroidered part has the following aspects and characteristics.

[0022] The shape of the embroidered portion is not particularly limited as long as it allows for the acquisition and input of biosignals, and can be appropriately selected depending on the application, such as round, oval, triangular, rectangular, polygonal, or a shape with uneven portions.

[0023] [Features of fiber electrodes (1)] In the present invention, the area of ​​the fiber electrode surface where the stitches are present, i.e., the embroidered area, is 0.1 cm 2 It is characterized by being more than 0.2 cm, preferably 0.2 cm 2 That's all.

[0024] The size (area) of the embroidered part is 0.1 cm 2 If it is less than this, the ability to obtain biosignals will be poor. On the other hand, there is no particular upper limit on the size of the embroidery part, but it is usually 150 cm 2 Less than or equal to 100 cm 2 Less than 50cm, preferably 50cm 2 Less than 25cm, more preferably 2 Less than 20cm, more preferably 20cm 2 The size of the embroidery part is 150cm. 2 If the frequency exceeds this range, noise other than the biological signal becomes easily obtained, which is not preferable.

[0025] The size (area) of the embroidery part is preferably 0.1 to 150 cm. 2 , more preferably 0.2 to 100 cm 2 , and more preferably 0.2 to 50 cm 2 , and even more preferably 0.2 to 25 cm 2 , and particularly preferably 0.2 to 20 cm 2 It is.

[0026] [Features of fiber electrodes (2)] The conductive yarn used to form the fiber electrode in the present invention is a composite yarn containing organic fibers and metal fibers. The use of the composite yarn containing organic fibers and metal fibers can solve the problem of durability against repeated use that occurs when using metal-plated yarn, that is, the problem of deterioration of conductive performance due to peeling or separation of metal from the fiber electrode due to repeated use.

[0027] The conductive yarn is a composite yarn containing organic fibers and metal fibers, and among these, it is preferable that the conductive yarn is a twisted yarn in which both of the above-mentioned fibers are twisted together, and it is more preferable that the conductive yarn is a twisted yarn in which a core yarn is covered with a sheath yarn (hereinafter, sometimes referred to as a "core-sheath composite twisted yarn").

[0028] (Organic Fiber) Examples of organic fibers used in the conductive yarn of the present invention include natural fibers such as cotton, hemp, wool, and silk, synthetic fibers such as polyester, nylon, acrylic, polyolefin, para-aramid, meta-aramid, polyarylate, and polybenzoxazole, and regenerated fibers such as rayon. Among these, it is preferable to use multifilaments of synthetic fibers such as nylon and polyester, from the viewpoint of high versatility and excellent durability.

[0029] As described later, in order to expose more of the metal fibers on the surface of the fiber electrode, water-soluble fibers such as water-soluble vinylon and alkali-soluble fibers that can be dissolved in an alkaline solution can be used as the organic fibers. Examples of alkali-soluble fibers include fibers made of polycaprolactone resin, polylactic acid resin, polyhydroxybutyrate resin, polyglycolic acid resin, polyethylene adipate resin, and copolymerized polyester resin using a specific copolymerization component. Among these, fibers made of copolymerized polyester resin and / or polylactic acid resin are preferred.

[0030] Examples of the copolymer polyester resin include those in which an aromatic dicarboxylic acid having a metal sulfonate group is contained as a copolymer component in the acid component constituting the polyester. Examples of the aromatic dicarboxylic acid having a metal sulfonate group include 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, 5-lithium sulfoisophthalic acid, sodium sulfonaphthalenedicarboxylic acid, sodium sulfophenyldicarboxylic acid, and 5-sodium sulfoterephthalic acid. The aromatic dicarboxylic acid is preferably contained in an amount of 0.5 to 5 mol % when the total amount of all acid components in the copolymer polyester resin is taken as 100 mol %.

[0031] The organic fiber may be in the form of any of spun yarn, filament yarn, composite yarn, and a combination of these yarns, among which it is preferable to use a multifilament as described above. The organic fiber may be raw yarn that has not been false-twisted, or may be false-twisted yarn. The organic fiber may be a twisted yarn made from raw yarn or false-twisted yarn.

[0032] The cross-sectional shape of the organic fiber is not particularly limited, and may be any of a circular cross section, an irregular cross section, a hollow cross section, etc. The organic fiber may contain titanium dioxide, silicon dioxide, a pigment, etc., depending on the properties to be imparted.

[0033] The organic fiber is preferably a spun yarn or a multifilament. In the case of a spun yarn, the thickness is preferably 10 to 100, more preferably 15 to 80, and even more preferably 20 to 70. In the case of a multifilament, the single fiber fineness is preferably 0.3 to 10 dtex, the number of single fibers is preferably 5 to 150, and the total fineness is preferably 8 to 330 dtex. The total fineness is more preferably 10 to 170 dtex, and even more preferably 20 to 100 dtex.

[0034] (Metal Fiber) Examples of metal fibers used in the conductive yarn of the present invention include metal-coated fibers obtained by coating, plating, metal deposition, or sputtering a fiber surface with a metal such as copper, nickel, or silver; metal fibers made of metals (simple elements) such as aluminum and tungsten; and conductive fibers such as fibers containing fine particles of carbon, conductive ceramics, or metals. In the present invention, of these, from the viewpoint of increasing conductivity, it is preferable to use metal fibers made of simple elements, and it is more preferable to use metal yarns, which are metal fibers made of simple elements and are continuous metal wires.

[0035] Examples of materials for metal fibers made of a single metal include gold, silver, copper, brass, platinum, iron, steel, zinc, tin, nickel, stainless steel, aluminum, tungsten, and molybdenum. Among these, at least one filament selected from tungsten, molybdenum, and stainless steel is preferable because of its excellent corrosion resistance and strength, and tungsten is more preferable, and tungsten metal yarn is even more preferable. These metals may be used alone or in combination of two or more kinds. The material for the metal fiber may also be an alloy made of two or more kinds of metals.

[0036] Furthermore, the metal fibers used in the conductive yarn of the present invention may be monofilament yarns of the above-mentioned metal fibers (for example, monofilament yarns (metal yarns) of metal fibers made of a single metal or monofilament yarns of metal-coated fibers, etc.), or multifilament yarns in which multiple types of metal fibers are twisted or aligned may be used.

[0037] When using a single monofilament thread of metal fiber, it is preferable that the monofilament thread is not twisted (single twist). When using a combination of multiple types of metal fibers, it is preferable that the multifilament thread is made of multiple types of metal fibers twisted together (single twisted).

[0038] The thickness of the metal fibers is not particularly limited, but the diameter of the metal fibers is preferably 2 to 150 μm, more preferably 2 to 100 μm, even more preferably 5 to 50 μm, and even more preferably 10 to 20 μm. If the diameter is less than 2 μm, the composite yarn will have poor conductivity and strength. If the diameter exceeds 150 μm, defects are likely to occur when forming an embroidered portion using the composite yarn, and the metal fibers on the surface of the obtained fiber electrode will be more noticeable in appearance, resulting in poor flexibility and texture.

[0039] The electrical resistance of metal fibers (metal threads) is 1×10 -4 ~1×10 10 Ω / m is preferred, and 1×10 -4 ~1×10 5 Ω / m is more preferable, 1×10 -4 ~1×10 3 It is more preferably Ω / m. In the present invention, the electrical resistance of the metal fiber (metal thread) is measured by measuring the electrical resistance of a 1 m sample of the metal fiber in an environment of 23° C., and the average electrical resistance of five samples is used.

[0040] (Sheath-core composite twisted yarn) The conductive yarn in the present invention is preferably a core-sheath composite twisted yarn formed by covering a core yarn with a sheath yarn, as described above. The core-sheath composite twisted yarn is a twisted yarn made of a core yarn and a sheath yarn that is wound around the outer periphery of the core yarn and covers it, and it is preferable that both the core yarn and the sheath yarn are twisted yarns containing organic fibers.

[0041] As a more specific form of the core-sheath composite twisted yarn, the following form 1 or form 2 is preferable. Form 1: Two types of sheath yarns, metal fiber and organic fiber B, are wound around a core yarn made of organic fiber A in the S or Z twist direction. Form 2: A sheath yarn of organic fiber B is wound around the outer circumference of a core yarn made of organic fiber A and metal fiber in the S or Z twist direction.

[0042] In the present invention, by using the conductive yarn as a core-sheath composite twisted yarn as in Form 1 or Form 2, the fiber electrode can easily follow the movement of various actions and can stably contact with the skin, thereby stably acquiring biosignals and inputting electrical signals to apply electrical stimulation. In addition, durability against repeated use, shape stability after washing, and operability during embroidery are also excellent.

[0043] When the core-sheath composite twisted yarn is prepared, the organic fiber A used for the core yarn and the organic fiber B used for the sheath yarn may be the same or different. The conductive yarn is preferably a twisted yarn N obtained by twisting two or more core-sheath composite twisted yarns (twisted yarn M) of form 1 or form 2. By using the twisted yarn N as the conductive yarn, the metal fibers contained in each twisted yarn M contact each other in the twisted yarn N, resulting in a twisted yarn with better conductive performance. Therefore, by using the twisted yarn N, the number of contact points between the metal fibers in the fiber electrode is increased, and a fiber electrode with better conductive performance can be obtained. The number of twisted yarns is preferably 2 to 9, and more preferably 4 to 8. If the number of twisted yarns is within the above range, the number of contact points between the metal fibers can be increased, and the twisted yarn N does not become too thick, so that the surface of the fiber electrode does not become thick or hard when used in the fiber electrode, and the fiber electrode can easily follow the movement of various operations.

[0044] In addition, when the fiber electrode comes into contact with the object to which an electric signal is to be transmitted or received, that is, the surface of a living body that emits or receives an electric signal, it is preferable to have more metal fibers exposed on the surface of the conductive yarn and more metal fibers exposed on the surface of the fiber electrode so that more metal fibers in the conductive yarn can come into contact with the surface of the living body. Examples of methods for exposing more metal fibers on the surface of the conductive yarn include arranging metal fibers in the sheath yarn of the core-sheath composite twisted yarn (the above-mentioned form 1) and performing a twisting process so that the metal fibers appear on the yarn surface. Examples of methods for exposing more metal fibers on the surface of the fiber electrode include using water-soluble fibers such as water-soluble vinylon or alkali-soluble fibers that can be dissolved in an alkaline solution as at least a part of the organic fibers in the core-sheath composite twisted yarn, embroidering the core-sheath composite twisted yarn on a base sheet, and then dissolving the water-soluble fibers or alkali-soluble fibers using hot water or an alkaline solution. In this case, it is preferable to use water-soluble fibers or alkali-soluble fibers as the organic fibers of the sheath yarn of the core-sheath composite twisted yarn. Specifically, it is more preferable that after embroidering the core-sheath composite twisted yarn, all of the water-soluble fibers or alkali-soluble fibers of the sheath yarn are dissolved, so that only the organic fibers of the core yarn and the metallic fibers of the sheath yarn remain on the surface of the obtained fiber electrode.

[0045] [Features of fiber electrodes (3)] In order for the fiber electrode of the present invention to have a conductive performance capable of sufficiently acquiring a biosignal, which is a weak electrical signal, and / or providing an electrical stimulus, the conductive thread must be present at a certain density in the embroidered portion where the conductive thread is stitched, and the fiber electrode must contain a specific amount of metal fiber. That is, the fiber electrode of the present invention must have a metal fiber content of 0.001 to 0.1 g / cm in the embroidered portion. 2 It is necessary that the density is 0.003 to 0.08 g / cm 2 It is preferable that the metal fiber content is 0.001 g / cm 2 When the metal fiber content is less than 0.1 g / cm, the biosignal cannot be obtained sufficiently because the metal fiber content is too small. 2If the metal fiber content exceeds 0.003 to 0.05 g / cm, the metal fiber content becomes too high, making the surface of the embroidered electrode hard, making it difficult to follow the movements of various actions, and making the texture poor when it comes into contact with the skin. When using tungsten, which is the most preferable metal fiber, the metal fiber content in the embroidered part is 0.003 to 0.05 g / cm. 2 and preferably 0.003 to 0.03 g / cm 2 More preferably, the density is 0.004 to 0.02 g / cm 2 More preferably, the density is 0.004 to 0.01 g / cm 2 It is particularly preferred that:

[0046] The content of organic fibers in the embroidered portion depends on the type of organic fiber, but when multifilament (e.g., polyester multifilament) is used, it is 0.001 to 0.5 g / cm 2 and preferably 0.003 to 0.1 g / cm 2 More preferably, the density is 0.003 to 0.05 g / cm 2 It is more preferable that:

[0047] Furthermore, in order to make the electrical resistance on the surface of the fiber electrode low and to obtain a fiber electrode that exhibits a surface resistance value described later, the conductive thread needs to be present at a certain density in the embroidered portion where the conductive thread is stitched. For this reason, the length (total length) of the metal fibers in the conductive thread included in the embroidered portion is 100 to 900 cm / cm. 2 It is preferable that the thickness is 120 to 500 cm / cm. 2 More preferably, it is 150 to 400 cm / cm 2 It is even more preferable that:

[0048] [Features of fiber electrodes (4)] The fiber electrode of the present invention has a surface resistance of 15 Ω / cm 2 It must be less than 13Ω / cm 2 It is preferable that the resistance is less than 10 Ω / cm 2 More preferably, it is 5 Ω / cm or less. 2More preferably, it is 3 Ω / cm or less. 2 More preferably, it is 2 Ω / cm or less. 2 It is particularly preferable that the surface resistance of the fiber electrode surface is 15 Ω / cm or less. The surface resistance of the fiber electrode surface is an index showing the conductive performance of the fiber electrode. 2 If the resistance exceeds this value, it becomes difficult to sufficiently acquire the biosignal, which is a weak electrical signal, or to input the electrical signal to the living body and apply an electrical stimulus thereto.

[0049] In the present invention, the surface resistance value on the surface of the fiber electrode is a value obtained by the following measurement method. How to measure surface resistance: When two arbitrary points are connected on the surface of the fiber electrode, the surface resistance is measured using a digital tester at the two points that are the longest distance apart. The measured value is converted from the electrode size (area) to a unit area of ​​1 cm. 2 The surface resistance value is the surface resistance value per 8 fiber electrodes. The surface resistance value is measured 6 times for each of the 8 fiber electrodes, and the average of the 48 measurements is the surface resistance value. The measurement environment is 20°C temperature and 65% humidity.

[0050] [Features of fiber electrodes (5)] As described below, the fiber electrode of the present invention is often used as a product attached to a base such as a woven fabric, knitted fabric, nonwoven fabric, felt, rubber, resin sheet, film, etc., and such products are often worn on a living body and are often used repeatedly. Therefore, the fiber electrode of the present invention has an absolute value of the change in surface resistance of the fiber electrode surface after 30 friction tests of 1 Ω / cm 2 It is preferable that the resistance is less than 0.5Ω / cm 2 More preferably, it is 0.3 Ω / cm or less. 2 It is more preferable that the value is not more than this. By satisfying this value, it is possible to maintain the conductive performance even after repeated use (the conductive performance has excellent durability).

[0051] In the present invention, the change in surface resistance of the fiber electrode surface after 30 friction tests is a value obtained by the following measurement method.

[0052] Measurement method of change in surface resistance: First, the surface resistance of the fiber electrode before the friction test is measured by the above method. Next, in the friction tester II type (Gakushin type) method of JIS L 0849:2013 (test method for color fastness to friction), the fiber electrode is attached to the friction element side of the friction tester II type (Gakushin type) method, and the white cotton cloth for friction is attached to the test piece table side, based on the case of the dry test of the friction tester II type (Gakushin type) method, specifically, the fiber electrode is rubbed back and forth against the white cotton cloth for friction 30 times under the conditions of a load of 2N, a speed of 30 reciprocations per minute, and a reciprocation distance of 100 mm. After the friction test, the fiber electrode is removed from the friction element, and the surface resistance of the fiber electrode is measured by the above method. Then, the absolute value of the difference between the surface resistance of the fiber electrode before and after the friction test is taken as the change.

[0053] [Features of fiber electrodes (6)] As described above, the fiber electrode of the present invention is washed frequently. Therefore, the fiber electrode of the present invention preferably has a dimensional retention of 85% or more, more preferably 90% or more, after 50 washes. If the dimensional retention is less than 85% after 50 washes, the conductive performance is likely to decrease or change due to dimensional changes caused by repeated washing.

[0054] In the present invention, the dimensional retention after 50 washes is a value obtained by the following measurement method and calculation formula. Dimensional retention after 50 washes: First, measure the surface area of ​​the fiber electrode before the washing test. Next, perform 50 washing tests based on the C4M method of JIS L 1930:2014 (Home washing test method for textile products). Use method A (hang-dry) as the drying method. Then, measure the surface area of ​​the fiber electrode after the washing test. Then, calculate the dimensional retention (%) using the following formula. Dimensional retention rate after 50 washings (%) = [(surface area of ​​fiber electrode after washing test) / (surface area of ​​fiber electrode before washing test)] × 100

[0055] [Characteristics of fiber electrodes (7)] The fiber electrode in the present invention is flexible because it is formed by embroidering conductive threads on a base sheet. The flexibility of the base sheet with fiber electrodes is evaluated using a thickness index T calculated by the following formula. The closer the value of the thickness index T is to 1, the easier it is to bend the electrode part with the fiber electrodes formed thereon, and the higher the flexibility is. The larger the value of the thickness index T is, the harder it is to bend the electrode part with the fiber electrodes formed thereon, and the lower the flexibility is. For example, when a hard material such as a plastic plate is used as the base sheet, the base sheet with fiber electrodes cannot be folded in half, T2 cannot be measured, and it can be said that it does not have flexibility. The thickness (mm) is measured according to the A method (JIS method) of "8.4 Thickness" of JIS L 1096:2010 (Fabric test method for woven and knitted fabrics). Thickness index T=(T2-T1) / T1 (T1: thickness of the base sheet with fiber electrodes, T2: maximum thickness of the base sheet with fiber electrodes when folded in half so that the fiber electrodes face each other and perpendicular to the embroidery direction of the conductive thread on which the fiber electrodes are embroidered)

[0056] In the base sheet with fiber electrodes of the present invention, the thickness index T is preferably 4.0 or less, more preferably 3.0 or less, and even more preferably 2.8 or less. If the thickness index T is 4.0 or less, the electrode part on which the fiber electrodes are formed has sufficient flexibility, so that the electrode part can stably contact the skin and easily conduct electric signals stably when performing various operations. Usually, the surface embroidered with thread has a certain degree of hardness, and the hardness varies depending on the thickness and number of threads, the density of the embroidery part, etc. Therefore, the lower limit of the thickness index T is not particularly limited, but is usually 1.0 or more, and may be 1.2 or more.

[0057] In the base sheet with a fiber electrode of the present invention, the thickness index T is preferably 1.0 to 4.0, more preferably 1.0 to 3.0, and even more preferably 1.0 to 2.8. In the base sheet with a fiber electrode of the present invention, the thickness index T may be 1.2 to 4.0, 1.2 to 3.0, or 1.2 to 2.8.

[0058] [Features of fiber electrodes (8)] In the fiber electrode of the present invention, the conductive thread is present at a certain density in the embroidered portion where the conductive thread is stitched, but depending on the thickness of the conductive thread and the embroidery conditions, there may be voids in the embroidered portion where the conductive thread is not stitched, i.e., where no conductive thread is present. In the base sheet with fiber electrode of the present invention, the ratio of the voids in the embroidered portion of the fiber electrode (porosity) is preferably 18% or less, more preferably 14% or less, even more preferably 10% or less, even more preferably 8% or less, and particularly preferably 6% or less. When the porosity is 18% or less, the conductive thread is present at a high density in the embroidered portion, and the number of contact points between the metal fibers increases, thereby making it possible to obtain a fiber electrode with better conductive performance. The lower limit of the porosity is not particularly limited as long as the effects of the conductive performance and flexibility described above are not impaired.

[0059] The porosity of the embroidered portion of the fiber electrode can be determined by image analysis, for example, using "ImageJ" (Wayne Rasband, National Institutes of Health) as image analysis software. As an image analysis method, a threshold value is set at the brightness boundary between the void portion in the embroidered portion and the portion where the conductive thread is present for the captured image of the base sheet with the fiber electrode, and the brightness is binarized. Generally, when binarized into white and black, the portion where the conductive thread is present becomes white and the void portion becomes black, so that the white portion can be identified as the portion where the conductive thread is present and the black portion as the void portion. The porosity is obtained by calculating the ratio of the total area of ​​the void portions identified as voids to the total area of ​​the embroidered portion.

[0060] [Features of fiber electrodes (9)] The fiber electrode of the present invention preferably has an impedance of a specific value or less as an index showing that an electrical signal can be easily acquired and input on the surface of a living body. In the present invention, the impedance is evaluated by a test in accordance with ANSI / AAMI EC12:2000. The AC impedance of the fiber electrode of the present invention is preferably 2 kΩ (2000Ω) or less, more preferably 1000Ω or less, even more preferably 100Ω or less, even more preferably 50Ω or less, even more preferably 30Ω or less, and particularly preferably 10Ω or less. In addition, the above standard requires that the impedance of a biological electrode at 10 Hz and not exceeding 100 μAp-p (Ap-p: difference between the maximum current value and the minimum current value measured with an alternating current) must be 2 kΩ or less. If the fiber electrode of the present invention has an AC impedance of 2 kΩ or less, the impedance between the surface of a living body and the fiber electrode is small, making it easy to acquire and input an electrical signal, and therefore it is preferable.

[0061] In the present invention, the AC impedance of the fiber electrode is a value obtained by the following measurement method.

[0062] Method for measuring AC impedance of fiber electrodes: Measurements are performed in accordance with ANSI / AAMI EC12:2000. Specifically, the procedure is as follows. Two substrate sheets with fiber electrodes are stacked so that the embroidered parts are joined to obtain a pair of samples. Then, a 100g weight is placed on top of the samples to apply pressure, and the AC impedance at 10 Hz is measured under conditions of 23°C and 40% humidity. The AC impedance is measured for five samples, and the average value is used.

[0063] The fiber electrode of the present invention has a small effect on impedance characteristics even when exposed to the atmosphere for a long time. That is, when a conventional gel electrode is exposed to the atmosphere for a long time, the gel evaporates, and the impedance increases, tending to deteriorate the impedance characteristics. On the other hand, the fiber electrode of the present invention has the above-mentioned configuration, and therefore the impedance does not change significantly even when exposed to the atmosphere for a long time, so that the effect on the impedance characteristics is small. Therefore, the fiber electrode of the present invention has an AC impedance of preferably 2 kΩ (2000Ω) or less, more preferably 1000Ω or less, even more preferably 100Ω or less, even more preferably 50Ω or less, even more preferably 30Ω or less, and particularly preferably 10Ω or less, after being left at 23°C x 55% RH for 24 hours.

[0064] In the present invention, the AC impedance of the fiber electrode after being left at 23°C x 55% RH for 24 hours is a value obtained by the following measurement method. The base sheet with the fiber electrode is left in an environment of 23°C x 55% RH for 24 hours, and then the AC impedance is measured by the same method as above. The AC impedance is measured for four samples, and the average value is used.

[0065] The base sheet with a fiber electrode of the present invention is often used by being attached to a living body as a product attached to a part of a substrate, and when used for such purposes, it is washed frequently. Therefore, in order to minimize the effect on impedance characteristics even after repeated washing and to enable stable acquisition and input of electrical signals, the fiber electrode of the present invention has an AC impedance of preferably 2 kΩ (2000Ω) or less, more preferably 1000Ω or less, even more preferably 100Ω or less, still more preferably 50Ω or less, even more preferably 40Ω or less, and particularly preferably 10Ω or less after 50 washes.

[0066] In the present invention, the AC impedance of the fiber electrode after 50 washes is a value obtained by the following measurement method. The base sheet with the fiber electrode is washed 50 times based on the C4M method of JIS L 1930:2014 (Home Washing Test Method for Textile Products). The drying method is Method A (hang-dry). Then, the AC impedance is measured by the same method as above. The AC impedance is measured for four samples, and the average value is used.

[0067] [Features of fiber electrodes (10)] The fiber electrode in the present invention may have water absorption properties due to water absorption processing. The water absorption processing method is not particularly limited, but examples include a method of attaching a compound (water absorbent) having a hydrophilic group to the surface of the fiber electrode by coating, adsorption, or exhaustion. Specifically, any of padding method, exhaustion method, spray method, kiss roll coater method, slit coater method, etc. may be adopted to apply an aqueous solution containing a water absorbent to the surface of the fiber electrode, and the treatment may be performed under normal temperature and normal pressure conditions, or a dry heat treatment may be performed at 105 to 190 ° C for 30 to 150 seconds. In addition, a conductive thread having water absorption properties may be used to form the fiber electrode. The water absorption processing may be performed on at least the surface of the fiber electrode, and may be performed on both the front and back sides of the fiber electrode.

[0068] In the present invention, by imparting water absorbency to the surface of the fiber electrode, the effect of further improving the conductive performance and the effect of lowering the impedance can be obtained. In addition, when the fiber product of the present invention is worn on the human body, it is possible to suppress the surface of the fiber electrode from being easily separated from the wearer's skin due to sweat, and to reduce discomfort caused by sweat remaining on the skin surface without being absorbed by the fiber electrode.

[0069] <Method of manufacturing base sheet with fiber electrodes> The method for producing the base sheet with the fiber electrode of the present invention is not particularly limited, and examples thereof include a method of forming a fiber electrode composed of an embroidered portion by embroidering the base sheet with the conductive thread. Methods for forming a fiber electrode having the above characteristics include using the conductive thread in the embroidered portion, forming the embroidered portion by machine embroidery, forming the types of stitches (stitches that appear on the surface by embroidery) shown below, or forming the stitch lengths, row intervals, and offset values ​​shown below.

[0070] The types of stitches include running stitch, cross stitch, tatami stitch, chain stitch, etc. Of these, running stitch and tatami stitch are preferred.

[0071] The stitch length is preferably 1 to 10 mm, and more preferably 2 to 8 mm. The row spacing is preferably 0.1 to 1.5 mm, and more preferably 0.3 to 1.3 mm. The row spacing refers to the spacing between stitch lines when forming stitches, but in the case of a backstitch line such as tatami stitch, it refers to the spacing between stitch line 1 and stitch line 2 when stitch line 1, backstitch line, and stitch line 2 are formed in this order.

[0072] The offset value refers to the absolute value of the length of the shift between the needle points of adjacent stitch lines, and in the case of a backstitch line as described above, the offset value refers to the absolute value of the length of the shift between the needle points of a stitch line and the backstitch line adjacent to it. The offset value is preferably 0.5 to 1.0 mm, and more preferably 0.6 to 0.9 mm.

[0073] The embroidered portion where the conductive thread is stitched onto the base sheet preferably has stitches arranged so that the conductive thread crosses in two different directions. For example, a running stitch may be performed by understitching in the weft direction, and then by lockstitching in the warp direction. By having such understitching, the number of contact points between the metal fibers in the embroidered portion increases, further improving the conductive performance.

[0074] When the two different directions are the warp direction and the weft direction, the two threads cross at 90 degrees, and the angle at which the two threads cross is preferably 20 to 160 degrees, and more preferably 30 to 150 degrees.

[0075] The stitch type, stitch length, row spacing, and offset value of the understitch may be the same as those of the lockstitch described above, but the row spacing of the understitch is preferably 2 to 6 times that of the lockstitch.

[0076] <Applications of the base sheet with fiber electrodes> The base sheet with fiber electrodes of the present invention can be used as a biological electrode. Preferred embodiments of the base sheet with fiber electrodes used as a biological electrode include those that can directly contact a living body to obtain a biological signal and / or provide an electric signal or electric stimulation, such as an electrode for obtaining a biological signal such as cardiac potential, myoelectric potential, or electroencephalogram, and an electrode for providing an electric stimulation to a living body, such as a low-frequency, high-frequency, or EMS electrode.

[0077] As described below, a biological electrode using the base sheet with a fiber electrode of the present invention can be attached to at least a part of a base and used as a product that can acquire biological signals and / or impart electrical signals or electrical stimuli.

[0078] <Products with base sheet with fiber electrodes> The product of the present invention has a base sheet with a fiber electrode. Examples of the product having a base sheet with a fiber electrode include a product having a base (woven fabric, knitted fabric, nonwoven fabric, felt, rubber, resin sheet, film, etc.) on which a fiber electrode is directly formed at least partially, and a product having a base sheet with a fiber electrode fixed to the base. The base sheet with a fiber electrode may be detachable from the base.

[0079] An example of a substrate having fiber electrodes formed directly on the substrate is a substrate having an embroidered portion formed on the substrate itself by stitching conductive thread directly onto the substrate. In this case, the substrate corresponds to the substrate sheet of the substrate sheet with fiber electrodes.

[0080] The method of fixing the base sheet with fiber electrodes to the base is not particularly limited, but examples thereof include adhesion, sewing using conductive thread, soldering, etc. In addition, the method of making it detachable is also not particularly limited, but examples thereof include providing magnets, buttons, hooks, snap buttons, hook-and-loop fasteners, etc. on the base and the base sheet with fiber electrodes. Products that allow the base sheet with fiber electrodes to be detachable have the advantage that, for example, the base sheet with fiber electrodes can be installed so that an electrical signal can be acquired or input at a desired location, or the base sheet with fiber electrodes can be installed and used on another base. In addition, the base sheet with fiber electrodes of the present invention is washable, but by washing only the base sheet with the base sheet with the fiber electrodes removed during washing, the load on the base sheet with fiber electrodes can be reduced and the durability of the base sheet with fiber electrodes can be improved.

[0081] The base sheet with fiber electrodes may be fixed entirely to the substrate, or at least partially. When only a portion of the base sheet with fiber electrodes is fixed to the substrate, the base sheet with fiber electrodes does not inhibit expansion and contraction of the product, i.e., when the product is attached to a living body and expands and contracts due to body movements, and the base sheet with fiber electrodes can flexibly follow the movements of the body, thereby achieving a high fit of the fiber electrodes to the surface of the living body.

[0082] The product having the base sheet with fiber electrodes is not particularly limited, and examples thereof include textile products. When the textile product is clothing, the clothing may be either upper or lower clothing, and specific examples thereof include innerwear, sportswear, hospital clothing, nightwear, various uniforms, and the like. In addition to clothing, the base sheet with fiber electrodes can also be attached to various clothing that comes into contact with a part of the living body, and can be used for, for example, wristbands, gloves, socks, supporters, corsets, belly wraps, hats, and other belt-like items such as belts and bands. In the case of a belt-like item, for example, two fiber electrodes can be attached to one belt-like item to form a product in which the two fiber electrodes are integrated, and the product can be easily set by wearing the product on a part where a biosignal is to be acquired or an electrical signal is to be input. Specific examples include chest belts, abdominal belts, and leg belts. In addition to the textile products, the base sheet with fiber electrodes can also be used for products that come into contact with a part of the living body, and can also be used for products such as watches, chairs, beds, carpets, handlebars, and various covers. Products having such fiber electrodes can be used as products capable of acquiring biosignals and / or imparting electrical signals or electrical stimuli by using the fiber electrodes as biological electrodes as described above.

[0083] A product having a base sheet with a fiber electrode may be equipped with wiring, connectors, electronic control units such as a biosignal detection device or an electrical stimulation device, or an electronic control unit that can be attached or detached via a connector, as necessary, to ensure electrical continuity.

[0084] The type of connector attached to the fiber electrode of the base sheet with fiber electrode of the present invention is not particularly limited, but when used in products such as the above-mentioned clothing, supporters, covers, etc., small and lightweight connectors are preferred to prevent the user from feeling uncomfortable when the connector comes into contact with the body, and examples of such connectors include snap buttons and conductive seal-shaped connectors, as well as soldering, adhesion with conductive paste, sewing with conductive thread, magnets, hooks, etc. In order to prevent noise from being generated when acquiring or inputting an electrical signal through the fiber electrode of the present invention, it is preferable that these connectors are insulated, and for example, insulated buttons made of stainless steel are preferably used from the viewpoint of excellent washing durability.

[0085] In a product having a base sheet with fiber electrodes, the number of fiber electrodes attached to the base may be multiple and can be changed appropriately depending on the type of biosignal to be collected, or the application, such as obtaining a biosignal and / or electrical stimulation by inputting an electrical signal, but it is preferable for the number to be 1 to 50, and more preferably 1 to 25.

[0086] Furthermore, when the fiber electrode of the present invention is used as a biological electrode, for example, by providing two or more fiber electrodes on the skin side of a product, it is possible to measure cardiac potential, myoelectric potential, etc. It is also possible to measure pulse, respiration, and movement state by providing fiber electrodes on the skin side or surface of a product and measuring changes in impedance of the body.

[0087] The position of the fiber electrode can be changed as appropriate depending on the type of biosignal to be collected, or the purpose of obtaining the biosignal and / or electrical stimulation by inputting an electrical signal. For example, when measuring electrocardiogram, it is preferable to place the fiber electrode near the left chest, and when measuring electromyogram or electroencephalogram, it is preferable to place the fiber electrode near the muscle or brain to be measured.

[0088] The biosignals collected by the fiber electrode of the present invention are measured over a long period of time using various devices depending on the purpose, analyzed as various data, and used in health management, sports training, the medical field, etc. In addition, the fiber electrode of the present invention can be used as a device for applying electrical stimulation by inputting an electrical signal to a muscle or nerve using the fiber electrode of the present invention in the medical field and training applications, games and toys, etc., or as an electrode for measuring the impedance of a living body. EXAMPLES

[0089] The present invention will now be described in more detail with reference to the following examples, in which the various property values ​​and the like are measured and evaluated as follows:

[0090] (a) The amount of metallic fibers and organic fibers contained in the embroidery part and the length (total length) of the metallic fibers The fiber electrode was separated into organic fibers and metal fibers, and the weight of each and the length (total length) of the metal fibers were measured. The content of the metal fibers or organic fibers in the embroidered part (g / cm) was calculated from the area of ​​the embroidered part and the weight of the metal fibers or organic fibers. 2 ) was calculated. In addition, the length (total length) of the metal fibers included in the embroidered part (cm / cm 2 ) was calculated.

[0091] (b) Electrical resistance of metal fibers For one metal fiber in the core-sheath composite twisted yarn constituting the conductive yarn used in the Examples and Comparative Examples, a 1 m sample was used to measure the electrical resistance value in an environment of 23° C. using a digital tester (OHM Digital Multi Tester TDB-401, manufactured by Ohm Electric Co., Ltd.) The average electrical resistance value of the five samples was taken as the electrical resistance value of the metal fiber.

[0092] (c) Surface resistance of the fiber electrode surface The surface resistance of the fiber electrode was measured at the two longest points between any two points on the surface of the fiber electrode using a digital tester (OHM Digital Multi Tester TDB-401, manufactured by Ohm Electric Co., Ltd.). The measured value was converted from the electrode size (area) to a unit area of ​​1 cm. 2 The surface resistance was measured six times for each of the eight fiber electrodes, and the average of the 48 measurements was recorded as the surface resistance. The measurement environment was 20°C and humidity 65%.

[0093] (d) Change in surface resistance on the fiber electrode surface after 30 friction tests First, the surface resistance value of the fiber electrode before the friction test was measured by the method described in (c) above. Next, in the friction tester II type (Gakushin type) method of JIS L 0849:2013 (test method for color fastness to friction), the fiber electrode was attached to the friction element side of the friction tester II type (Gakushin type) method, and the white cotton cloth for friction was attached to the test piece table side, but based on the case of the dry test of the friction tester II type (Gakushin type) method, specifically, the fiber electrode was rubbed back and forth against the white cotton cloth for friction 30 times under the conditions of a load of 2N, a speed of 30 reciprocations per minute, and a reciprocation distance of 100 mm. After the friction test, the fiber electrode was removed from the friction element, and the surface resistance value of the fiber electrode was measured by the method described above. Then, the absolute value of the difference between the surface resistance values ​​of the fiber electrode before and after the friction test was taken as the amount of change.

[0094] (e) Dimensional retention after 50 washes First, the surface area of ​​the fiber electrode was measured before the washing test. Next, a washing test was performed 50 times based on the C4M method of JIS L 1930:2014 (home washing test method for textile products). The drying method used was Method A (hanging dry). Then, the surface area of ​​the fiber electrode after the washing test was measured. The dimensional retention rate (%) was calculated using the following formula. Dimensional retention rate after 50 washings (%) = [(surface area of ​​fiber electrode after washing test) / (surface area of ​​fiber electrode before washing test)] × 100

[0095] (f)Flexibility According to JIS L 1096:2010 (Testing methods for woven and knitted fabrics), "8.4 Thickness", Method A (JIS method), the thickness T1 (mm) of the fabric sheet with fiber electrodes was measured using a thickness measuring instrument (Ozaki Manufacturing Co., Ltd., Peacock Model H). Next, the fiber electrodes were folded in half in a direction perpendicular to the embroidery direction of the embroidered conductive thread and so that the fiber electrodes faced each other, and the maximum thickness T2 (mm) of the fabric sheet with fiber electrodes in this state was measured in the same manner as above. Using the measured values ​​of T1 and T2, the thickness index T was calculated according to the following formula to evaluate the flexibility. Thickness index T=(T2-T1) / T1 (T1: thickness of the base sheet with fiber electrodes, T2: maximum thickness of the base sheet with fiber electrodes when folded in half so that the fiber electrodes face each other and perpendicular to the embroidery direction of the conductive thread on which the fiber electrodes are embroidered)

[0096] (g) Porosity in the embroidered part of the fiber electrode For the fabricated substrate sheet with fiber electrodes, an arbitrary 2 cm × 2 cm area (total area 4 cm) of the embroidery part was 2 The porosity (%) was obtained by calculating the ratio of the total area of ​​the void portion where the conductive thread does not exist per 100 mm. Specifically, the porosity (%) was calculated by binarizing the brightness of the image taken from directly above the center of the embroidery portion of the base sheet with fiber electrodes using the image analysis software "ImageJ" (Wayne Rasband, National Institutes of Health), setting the threshold value of the brightness boundary between the void portion in the embroidery portion and the portion where the conductive thread exists to 80. In addition, in the calculation of the porosity, when the portion that is not a void is calculated as a void portion and has a large influence on the porosity, the image was manually edited and the portion that is not a void was calculated as a portion where the conductive thread exists. FIG. 2 is an explanatory diagram showing the image analysis of the base sheet with fiber electrodes obtained in Example 2. Figure 2(a) is an image after a photograph taken from directly above the center of the embroidered part of the base sheet with a fiber electrode was converted to 8-bit, and Figure 2(b) is an image showing the result of extracting the void parts in order to calculate the porosity by image analysis, where the parts 4 where the conductive thread exists are shown in white and the void parts 3 are shown in black.

[0097] (h) Initial state impedance The impedance of the initial state of the fiber electrode was measured in accordance with ANSI / AAMI EC12:2000. Specifically, the measurement was performed by the following method. Two sheets of base material sheets with fiber electrodes were prepared in each of the examples, comparative examples, and reference examples. A stainless steel one-sided rivet (terminal) with a diameter of 10 mm was attached to the embroidered part of a square of 1 cm x 1 cm (the small square part at the top of the convex electrode shown in Figure 1). At that time, the metal fittings on the surface side of the fiber electrode were protected with an insulating material. Then, two base material sheets with fiber electrodes were stacked so that the embroidered parts were joined to obtain a pair of samples. Then, a crocodile clip-type measurement probe terminal was connected to the rivet of each fiber electrode under the condition of applying pressure by placing a 100g weight on top of the sample, and the AC impedance at 10 Hz was measured under the conditions of 23 ° C and 40% humidity. An impedance analyzer (HIOKI ELECTRIC CO., LTD., IM3570) was used to measure the AC impedance. The AC impedance was measured for five samples, and the average value was taken as the impedance of the initial state of the fiber electrode.

[0098] (i) Impedance after exposure to air The base sheet with fiber electrodes prepared in the Examples, Comparative Examples, and Reference Examples was left in an environment of 23°C x 55% RH for 24 hours. After that, the AC impedance at 10 Hz was measured using the obtained samples by the method described in (h) above. The AC impedance was measured for four samples, and the average value was used as the impedance of the fiber electrodes after exposure to the atmosphere.

[0099] (j) Impedance after 50 washes Based on the C4M method of JIS L 1930:2014 (Home Laundry Test Method for Textile Products), the fabricated substrate sheet with fiber electrodes was washed 50 times to obtain a sample. The drying method used was Method A (hang-dry). The AC impedance at 10 Hz was measured using the obtained sample by the method described in (h) above. The AC impedance was measured for four samples, and the average value was used as the impedance of the fiber electrodes after 50 washes.

[0100] <Example 1> The following core yarn and sheath yarn were prepared as conductive yarns, and twisted at 300 times / m (S twist) using a covering twisting machine to obtain a core-sheath composite twisted yarn in which one core yarn was covered with two sheath yarns. Seven of the obtained core-sheath composite twisted yarns were then twisted together to obtain a conductive yarn.

[0101] (Structure of core-sheath composite twisted yarn) Core thread: Organic fiber A, 1 polyester multifilament (55dtex / 144f) Sheath thread: One tungsten metal yarn (diameter 13 μm) as the metal fiber Sheath thread: Organic fiber B, 1 nylon 6 multifilament (13dtex / 7f)

[0102] (Base sheet) Needle-punched polyester staple nonwoven fabric (thickness 1.19 mm, basis weight 240 g / m 2 )

[0103] Next, the conductive thread was used for the main stitching and understitching, and the polyester multifilament (organic fiber A) used for the core thread was used for the lower thread (the thread that appears on the back side of the fiber electrode). A single-head embroidery machine (TMEZ-SC, manufactured by Tajima Industries Co., Ltd.) was used to embroider the base sheet in the following configuration to form the fiber electrode shown in Figure 1 (having an embroidered area consisting of a 2 cm x 2 cm square and a 1 cm x 1 cm square), and a base sheet with a fiber electrode was produced. Stitch type: Tatami stitch, stitch length: 3mm, row spacing: 1.2mm, offset value: 0.77mm Underlay: Stitch type = Tatami stitch, Stitch length = 2mm, Row spacing = 6mm, No offset In the understitch and lockstitch, the conductive threads cross at right angles (90 degrees) in the warp and weft directions.

[0104] <Example 2> The following core yarn and sheath yarn were prepared as conductive yarns, and a core-sheath composite twisted yarn was obtained in the same manner as in Example 1. Next, five of the obtained core-sheath composite twisted yarns were plyed together to obtain a conductive yarn.

[0105] (Structure of core-sheath composite twisted yarn) Core thread: Organic fiber A, 1 polyester multifilament (55dtex / 144f) Sheath thread: One tungsten metal yarn (diameter 13 μm) as the metal fiber Sheath thread: Organic fiber B, 1 nylon 6 multifilament (13dtex / 7f)

[0106] (Base sheet) Needle-punched polyester staple nonwoven fabric (thickness 1.19 mm, basis weight 240 g / m 2 )

[0107] Next, a base sheet with a fiber electrode was produced in the same manner as in Example 1, except that the base sheet was embroidered in the following manner using the conductive thread in the main stitching and understitching. Main stitch: Stitch type = Tatami stitch, Stitch length = 3mm, Row spacing = 0.77mm, Offset value = 0.77mm Underlay: Stitch type = Tatami stitch, Stitch length = 2mm, Row spacing = 6mm, No offset In the understitch and lockstitch, the conductive threads cross at right angles (90 degrees) in the warp and weft directions.

[0108] <Example 3> The base sheet with the fiber electrode prepared in Example 2 was impregnated in an aqueous solution obtained by adding a polyester-based SR agent "Parasorb PET2" (manufactured by Ohara Palladium Co., Ltd.) to water (5 g per 100 ml) as a water absorbing agent, and the water absorbing agent was adhered to the front and back surfaces of the fiber electrode. Then, the base sheet with the fiber electrode that had been subjected to water absorption processing was prepared by drying in a dryer at 100°C for 20 minutes.

[0109] <Example 4> The following core yarn and sheath yarn were prepared as conductive yarns, and twisted at 300 times / m (S twist) using a covering twisting machine to obtain a core-sheath composite twisted yarn in which one core yarn was covered with two sheath yarns. Next, five of the obtained core-sheath composite twisted yarns were twisted together to obtain a conductive yarn.

[0110] (Structure of core-sheath composite twisted yarn) Core thread: Organic fiber A, 1 polyester multifilament (55dtex / 144f) Sheath thread: One tungsten metal yarn (diameter 13 μm) as the metal fiber Sheath thread: Organic fiber B, 1 polylactic acid filament (33dtex / 18f)

[0111] (Base sheet) Needle-punched polyester staple nonwoven fabric (thickness 1.19 mm, basis weight 240 g / m 2 )

[0112] Next, the conductive thread was used for the main stitching and understitching, and the polyester multifilament (organic fiber A) used for the core thread was used for the lower thread (thread appearing on the back surface of the fiber electrode) to embroider the substrate sheet with the following configuration using a single-head embroidery machine (TMEZ-SC, manufactured by Tajima Industries Co., Ltd.). After that, the polylactic acid filaments in the conductive thread were alkaline-eluted using a known device to form the fiber electrode shown in Figure 1 (having an embroidered portion consisting of a 2 cm x 2 cm square and a 1 cm x 1 cm square), thereby producing a substrate sheet with a fiber electrode. The surface of the fiber electrode of the obtained substrate sheet with a fiber electrode had a large amount of exposed metal fibers due to the elution of the polylactic acid filaments. Main stitch: Stitch type = Tatami stitch, stitch length = 3mm, row spacing = 0.8mm, offset value = 0.77mm Underlay: Stitch type = Tatami stitch, Stitch length = 2mm, Row spacing = 6mm, No offset In the understitch and lockstitch, the conductive threads cross at right angles (90 degrees) in the warp and weft directions.

[0113] <Example 5> A base sheet with a fiber electrode was produced in the same manner as in Example 4, except that a laminate having the following configuration was used as the base sheet. (Base sheet) Laminate: A laminate in which a surface knitted fabric, a film, and a back knitted fabric are laminated in this order (thickness 0.755 mm, basis weight 284 g / m 2 ) Surface fabric: Warp knitted fabric made of polyethylene terephthalate yarn (75dtex72fil) Film: Polycarbonate-based polyurethane resin film Backside knitted fabric: Warp knitted fabric made of polyethylene terephthalate yarn (56dtex36fil)

[0114] <Comparative Example 1> The following metal-plated threads were used as conductive threads: (Metal-plated thread) Ag-plated thread (Osaka Electric Industry Co., Ltd., ODEX, 78dtex / 24f)

[0115] Next, embroidery was performed on the base sheet in the following manner in the same manner as in Example 2, except that the conductive thread was used in the main stitching and understitching, to produce a base sheet with a fiber electrode. Main stitch: Stitch type = Tatami stitch, Stitch length = 3mm, Row spacing = 0.77mm, Offset value = 0.77mm Underlay: Stitch type = Tatami stitch, Stitch length = 2mm, Row spacing = 6mm, No offset In the understitch and lockstitch, the conductive threads cross at right angles (90 degrees) in the warp and weft directions.

[0116] <Reference example 1> Instead of the conductive yarn, a ply-twisted yarn made of five polyester multifilaments (55 dtex / 144 f) was prepared. Then, the ply-twisted yarn was used in the main stitching and understitching, and the laminate used in Example 5 was used as the base sheet. In the same manner as in Example 2, except that, embroidery was performed on the base sheet with the following configuration, to produce a base sheet with a fiber electrode. Main stitch: Stitch type = Tatami stitch, Stitch length = 3mm, Row spacing = 0.77mm, Offset value = 0.77mm Underlay: Stitch type = Tatami stitch, Stitch length = 2mm, Row spacing = 6mm, No offset In the understitch and lockstitch, the conductive threads cross at right angles (90 degrees) in the warp and weft directions.

[0117] <Reference example 2> We used the "Blue Sensor" electrocardiogram electrode (model number: SP-00-S) manufactured by Metz.

[0118] The configurations and physical properties of the substrate sheets with fiber electrodes produced in Examples 1 to 5, Comparative Example 1, and Reference Example 1 are shown in Table 1.

[0119] [Table 1]

[0120] As is clear from Table 1, the base sheet with fiber electrode obtained in Examples 1 to 5 satisfies all of the above characteristics (1) to (4), and therefore has excellent conductive performance capable of acquiring a biosignal, which is a weak electrical signal, and is also unlikely to deteriorate or change in conductive performance even after repeated use. In addition, the base sheet with fiber electrode obtained in Examples 1 to 5 has excellent impedance in the initial state, and has little effect on impedance characteristics even after long exposure to the atmosphere and repeated washing. In addition, as is clear from the comparison with Reference Example 1, which does not contain conductive thread and has no conductivity, the fiber electrodes of the base sheet with fiber electrode obtained in Examples 1 to 5 have excellent electrical properties and are practically usable as bioelectrodes. The base sheet with fiber electrode obtained in Examples 1 to 5 also has a thickness index T that is not significantly different from that of Reference Example 1, in which the embroidery part is formed with thread that does not contain metal fibers, and is smaller than the gel electrode of Reference Example 2, and has excellent flexibility. In addition, it was found that the fiber electrodes of the base sheet with fiber electrode obtained in Examples 1 to 5 have a small porosity and the embroidery part with conductive thread is densely formed.

[0121] On the other hand, the base sheet with fiber electrode obtained in Comparative Example 1 had a high surface resistance value on the surface of the fiber electrode, poor electrical conductivity, and also had poor impedance compared to the base sheet with fiber electrode obtained in Examples 1 to 5. Furthermore, the base sheet with fiber electrode obtained in Comparative Example 1 had a high surface resistance value on the surface of the metal-plated yarn, poor electrical conductivity, and partial peeling of the metal caused a decrease in electrical conductivity, resulting in poor durability. [Explanation of symbols]

[0122] 1: Base sheet 2: Fiber electrode (embroidery part) 3: Void area (black) 4: Part where conductive thread is present (white)

Claims

1. A base sheet with a fiber electrode comprising a base sheet and a fiber electrode constituted by an embroidered portion including conductive thread, the base sheet with a fiber electrode satisfying all of the following characteristics (1) to (5). (1) The size of the embroidered part on the surface of the fiber electrode is 0.1 cm 2 That's all. (2) The conductive yarn is a composite yarn containing organic fibers and metal fibers. (3) The content of metal fibers in the embroidery part is 0.001 to 0.1 g / cm 2 It is. (4) The surface resistance of the fiber electrode surface is 15 Ω / cm 2 The following is the result. (5) The thickness index T calculated by the following formula is 4.0 or less. Thickness index T=(T2-T1) / T1 (T1: thickness of the base sheet with fiber electrodes, T2: maximum thickness of the base sheet with fiber electrodes when folded in half in a direction perpendicular to the embroidery direction of the conductive thread on which the fiber electrodes are embroidered and so that the fiber electrodes face each other)

2. The substrate sheet with fiber electrodes according to claim 1, wherein the metal fibers contained in the conductive yarn have a diameter of 2 to 150 μm.

3. The absolute value of the change in surface resistance of the fiber electrode surface after 30 friction tests is 1 Ω / cm 2 The substrate sheet with fiber electrodes according to claim 1 , wherein:

4. The substrate sheet with fiber electrodes according to claim 1 , wherein the fiber electrodes have a dimensional retention rate of 85% or more after 50 washings.

5. The substrate sheet with a fiber electrode according to claim 1 , wherein the porosity in the embroidered portion is 18% or less.

6. The substrate sheet with fiber electrodes according to claim 1 , wherein the embroidered portion has stitches in which conductive threads are arranged to cross each other.

7. The substrate sheet with fiber electrodes according to claim 1 , further comprising a water-absorbing agent on the surface of the fiber electrodes.

8. A product having at least a part thereof the substrate sheet with a fiber electrode according to any one of claims 1 to 7.

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