Stretchable conductive fabric

Abstract

To provide a stretchable conductive fabric which has sufficient stretchability, does not cause fracture of an applied metallic film due to stretching and can maintain high reliability of conductivity, and can be suitably used as a wearable device, an electromagnetic wave shielding material, a sensor electrode material, or the like.SOLUTION: A stretchable conductive fabric is obtained by applying a metallic film to a woven fabric containing crimped yarn in at least part of the warp yarn and / or the weft yarn, and has a tensile stress at 30% elongation which is 10 N / cm or less in at least one direction of the warp and the weft.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a stretchable conductive fabric that can be used as a wearable device, an electromagnetic wave shielding material, a sensor electrode material, etc., and that has a metal coating applied to a fabric that at least partially contains crimped yarns that include composite fibers made of two types of polyester resin components with different heat shrinkage rates. [Background technology]

[0002] In recent years, wearable devices have been developed, which are electronic devices with input / output and communication functions that are worn on the body. Among these, conductive fabrics can be used as wearable devices by mounting electronic components and sensors.

[0003] Wearable devices made from conductive fabrics can measure the biosignals and movements of humans and animals when worn, and are used in the medical and healthcare fields. Their usefulness is attracting attention in a variety of industries, including the environment and construction.

[0004] Conventional techniques for imparting electrical conductivity to fabric include weaving or knitting conductive threads (for example, Patent Document 1) and printing a conductive paste (for example, Patent Document 2).

[0005] However, the method of weaving or knitting conductive threads has problems such as the need for special equipment and limited flexibility in the shape of the conductive pattern.The method of printing conductive paste can result in insufficient conductivity, so the amount of paste printed needs to be increased to increase the conductivity, which tends to make the fabric stiff and heavy.Furthermore, there is a risk of cracking due to an inability to follow the flexibility of the fabric.

[0006] As a technology for imparting stretchability and conductivity to fabrics, an electromagnetic wave shielding sheet in which a conductive film is formed on the surface of the yarn forming the woven or knitted stitches has been proposed (Patent Document 3). However, woven fabrics using ordinary yarns such as general false-twisted (textured) yarns have insufficient stretchability, while knitted fabrics have sufficient stretchability but have problems with conductivity when stretched. Furthermore, knitted fabrics or fabrics using elastic yarns may be subject to excessive stretch.

[0007] If the elongation of the thread containing the metal coating is too great, the metal coating will break and conductivity will decrease, while if the stretchability is insufficient, as in the case of fabrics made with general false-twisted yarn, usability will decrease. There is a need for the development of conductive fabrics that have excellent stretchability and flexibility, as well as high conductivity reliability, and are suitable for wearable devices, etc.

[0008] As a fabric with excellent elasticity, a stretchable fabric using a composite fiber made of two types of polyester resins with different shrinkage properties has been proposed (for example, Patent Document 4), but it is not known that by imparting conductivity to such a stretchable fabric, a conductive fabric with excellent both elasticity and conductivity can be obtained. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-019064 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-151018 [Patent Document 3] Japanese Patent Application Publication No. 11-354981 [Patent Document 4] Japanese Patent Application Publication No. 2019-157321 Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a stretchable conductive fabric that has sufficient stretchability, is not subject to breakage due to stretching even when a metal coating is applied, and can maintain high reliability of conductivity, making it suitable for use as an electrode. [Means for solving the problem]

[0011] As a result of extensive research, the inventors have found that a fabric containing at least a portion of a crimped yarn containing a composite fiber made of two types of polyester resin components with different thermal shrinkage rates, to which a metal coating is applied, has sufficient stretchability, and the applied metal coating is less likely to break due to stretching, and can maintain high conductivity, resulting in a stretchable conductive fabric suitable for use in wearable devices (electrodes), and have completed the present invention.

[0012] That is, the present invention relates to the following stretchable conductive fabric. (1) A fabric made of a woven fabric containing crimped yarns in at least a part of the warp and / or weft yarns and having a metal coating applied thereto, The ratio of crimped yarns to all fibers constituting the woven fabric is 25 to 45% by mass, A stretchable conductive fabric characterized in that the stress at 30% elongation in at least one direction of the warp and / or weft is 10 N / cm or less.

[0013] (2) The stretchable conductive fabric according to (1), characterized in that in at least one direction of the warp and / or weft, the increase in resistance value when stretched 30% relative to the resistance value when unstretched is 30% or less.

[0014] (3) The crimped yarn is a composite fiber selected from the group consisting of a combination of polyethylene terephthalate resin and polybutylene terephthalate resin, a combination of polyethylene terephthalate resin and polytrimethylene terephthalate resin, and a combination of two polyethylene terephthalate resins having different physical properties, (1) characterized in that the structure of the composite fiber is a side-by-side type or an eccentric core-sheath type. The stretchable conductive fabric described above.

[0015] (4) (1) The woven fabric containing crimped yarns in at least a part of the warp and / or weft is a woven fabric containing crimped yarns in only one of the warp and weft. The stretchable conductive fabric described above.

[0016] (5) The stretchable conductive fabric according to (1), wherein the shrinkage rate of the woven fabric after heat processing is 10 to 50%. [Effects of the Invention]

[0017] The stretchable conductive fabric of the present invention has sufficient stretchability, especially excellent stretchability after the application of a metal coating, so that the applied metal coating does not break due to stretching and maintains high conductivity. It also has excellent flexibility and ability to follow shape changes such as bending. Such a stretchable conductive fabric of the present invention can be suitably used for wearable devices, electromagnetic wave shielding materials, sensor electrode materials, etc. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a micrograph (plan view) showing an example of the stretchable conductive fabric of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] The stretchable conductive fabric of the present invention is a fabric made of a woven fabric containing crimped yarns in at least some of the warp and / or weft yarns and having a metal coating applied thereto, characterized in that the stress at 30% elongation in at least one direction of the warp and / or weft yarns is 10 N / cm or less. In the following description, the fabric (woven fabric) before the metal coating is applied will be referred to as "highly stretchable fabric," and the fabric after the metal coating is applied will be referred to as "stretchable conductive fabric."

[0020] 1. Fabrics containing crimped yarn The fabric constituting the stretchable conductive fabric of the present invention is a woven fabric containing crimped yarns in at least some of the warp and / or weft yarns. Here, crimped yarns are elastic yarns that are thermally processed to form fine crimps, giving them bulk and stretchability.

[0021] There are no particular restrictions on the crimped yarn as long as it has these properties, but examples include those obtained by heat-treating composite fibers that combine two or more resin components with different physical properties, including shrinkage properties such as heat shrinkage rate.

[0022] A composite fiber is a fiber containing two or more fiber components in a single filament yarn, and this filament yarn can be used alone or in combination with a plurality of filaments to form a yarn, which can be used to form a fabric.

[0023] The conjugate fiber used in the present invention is not particularly limited as long as it can be crimped by heat processing or the like, and for example, conjugate fibers selected from the group consisting of the following (a) to (c) can be used.

[0024] (a) A combination of polyethylene terephthalate resin (PET) and polybutylene terephthalate resin (PBT), (b) A combination of polyethylene terephthalate resin (PET) and polytrimethylene terephthalate resin (PTT), (c) A combination of two types of polyethylene terephthalate (PET) resins with different physical properties

[0025] One of the factors that may cause crimping is that the composite fibers formed from the combination of (a) and the composite fibers formed from the combination of (b) have different heat shrinkage rates (for example, boiling shrinkage rates (boiling shrinkage values) as filaments measured in accordance with JIS L1017) due to differences in, for example, crystal structure, copolymerization components, viscosity, and molecular weight.

[0026] (c) is a combination of PET fibers that are the same but have different physical properties. Examples of such properties include heat shrinkage. Examples of composite fibers made from the combination of (c) include combinations of PET fibers that have different heat shrinkage (boiling point values) due to differences in crystal structure, copolymerization components, viscosity, etc.

[0027] Of two polyethylene terephthalate resins with different heat shrinkage rates, the one with a relatively high heat shrinkage rate is designated as component (A) and the one with a relatively low heat shrinkage rate is designated as component (B). For example, component (A) can be one whose filament boiling point is 10% or more (preferably 15% or more), and component (B) can be one whose filament boiling point is less than 10% (preferably 5% or less).

[0028] There are no particular restrictions on the difference in heat shrinkage rate as long as component (A) has a relatively higher heat shrinkage rate than component (B), but it is desirable to combine components (A) and (B) so that the heat shrinkage rate of component (A) is 0.1 to 4% higher than the heat shrinkage rate of component (B).

[0029] Examples of combinations of polyester resins with different heat shrinkage rates include a combination of polyethylene terephthalate and a high-shrinkage copolyester, and a combination of two types of polyethylene terephthalate with different viscosities.

[0030] High shrinkage copolymer polyester is a material in which a certain type of third component (copolymer component) is contained in the diol component and / or dicarboxylic acid that constitutes polyethylene terephthalate, thereby increasing the shrinkage rate.

[0031] Examples of the third component to be copolymerized to produce a high-shrinkage copolymerized polyester include diol compounds such as diethylene glycol, 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane, and 1,4-butanediol, and carboxylic acid compounds such as adipic acid, azelaic acid, and isophthalic acid.

[0032] Among these, polyesters copolymerized with 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane and / or isophthalic acid are preferred. In this case, although the copolymerization ratio of both components is not particularly limited, it is preferred that 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane is 2 to 6 mol% in the diol component and isophthalic acid is 4 to 8 mol% in the dicarboxylic acid component.

[0033] That is, the content of 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane is preferably 2 mol% or more in order to fully achieve the heat shrinkage rate and shrinkage force, and is preferably 6 mol% or less in order to avoid discoloration due to the light resistance of the polymer. The content of isophthalic acid is preferably 4 mol% or more in order to fully satisfy the shrinkage rate, and is preferably 8 mol% or less in order to easily maintain the melting point and heat resistance of the polymer.

[0034] The main component of the high shrinkage polyester is a polyester made of terephthalic acid and ethylene glycol, but other components such as a monomer for improving dyeability and a compound for improving heat resistance may also be contained.

[0035] Any of the above polyester resin components may contain various known compounding agents, such as pigments, matting agents, fluorescent brighteners, ultraviolet absorbers, antioxidants, antistatic agents, and ether bond inhibitors such as organic amines and organic carboxylic acid amides, during production or molding processing, as needed.

[0036] Generally, composite fibers are produced by thermally melting two or more raw polymers with different properties and fusing them while spinning them from a spinneret (composite spinning nozzle) (composite spinning method). Types of composite fibers include the side-by-side type, in which multiple (usually two types) fibers are spun simultaneously and bonded together to form a multi-layer (usually two-layer) fiber cross section; the sheath-core type, in which the core component is spun so that it is coated with the sheath component, resulting in a concentric core and sheath; and the eccentric sheath-core type, in which the core and sheath are not concentric but are offset from one another.

[0037] The side-by-side type joining shape may be any known shape such as a round cross section, a cocoon shape, a triangular cross section, a Y cross section, a U cross section, a flat cross section, etc., as long as it exhibits the crimping performance required in the present invention. Among these, a cocoon shape in which two almost round cross sections are joined is preferred.

[0038] The structure of the conjugate fiber that can be used in the present invention is not particularly limited, but is preferably a side-by-side type or an eccentric core-sheath type. The side-by-side type includes a fiber in which the two different polyester components (e.g., any combination of (a) to (c)) are bonded to each other.

[0039] Examples of eccentric core-sheath types include those in which the core uses PET and the sheath uses PBT, those in which the core uses PET and the sheath uses PTT, and those in which the core uses component (B) with a relatively low heat shrinkage rate and the sheath uses component (A) with a relatively high heat shrinkage rate.

[0040] The thickness (single yarn fineness) of the composite fiber (monofilament yarn) thus obtained is preferably 33 to 330 dtex, more preferably 33 to 110 dtex.

[0041] Preferred examples of the conjugate fiber of the present invention include a combination of PET and PBT, a combination of PET and PTT, and a combination of PET and high-shrinkage copolymerized PET.

[0042] The crimped yarn of the present invention is preferably a multifilament yarn (latently crimped multifilament yarn) containing the above-mentioned composite fiber that has been thermally processed. Fine crimps are formed by the thermal processing, resulting in a resilient yarn with bulk and stretchability, and a highly stretchable fabric made from the same.

[0043] The multifilament yarn (latently crimped multifilament yarn) before thermal processing is a bundle of multiple monofilament yarns made of composite fibers, and can be produced by conventional methods, such as bundling multiple monofilament yarns after melt spinning, or melt spinning them all at once using a melt spinning device having multiple composite spinning nozzles.

[0044] This latent crimped multifilament yarn may contain fibers other than the above-mentioned composite fibers. The other fibers may be mixed with the composite fibers to form the latent crimped multifilament yarn or crimped yarn. The other fibers may be selected from natural fibers, chemical fibers, and synthetic fibers. However, synthetic fibers are preferred, and polyester-based synthetic fibers are particularly preferred, because they can withstand the plating process for forming the metal coating described below.

[0045] The thickness (total fineness) of the potentially crimped multifilament yarn is preferably 33 to 330 dtex, more preferably 33 to 110 dtex, and the number of filaments is preferably 6 to 96.

[0046] The heat processing of the latently crimped multifilament yarn may be carried out in a thread-like state before it is formed into a fabric (woven fabric, knitted fabric, etc.), or it may be carried out after a fabric is formed using the latently crimped multifilament yarn before heat processing and then the fabric is heat processed. Preferably, the latently crimped multifilament yarn is used to form a fabric and then the fabric is heat processed. The heat processing method preferably involves immersion in hot water.

[0047] The crimped yarns used in the present invention may be commercially available products such as TEXBRID (registered trademark) manufactured by Chori MODA Co., Ltd. and FlexFusion (registered trademark) manufactured by Shinyu Co., Ltd., which are yarns using PET / PBT composite fibers, Solotex (registered trademark) manufactured by Teijin Frontier Co., Ltd., and Lycra (registered trademark) T400 manufactured by Toray Opelontex Co., Ltd., which are yarns using PET / PET composite fibers, and Espandi (registered trademark) manufactured by KB Seiren Co., Ltd., which are yarns using PET / PET composite fibers.

[0048] The fabric constituting the stretchable conductive fabric of the present invention is made of woven fabric. Woven fabrics have the advantage that they do not stretch too much, so that conductivity does not decrease (resistance does not increase) when deformed by stretching. The woven fabric of the present invention is a highly stretchable fabric that contains the above-mentioned crimped yarn in at least a portion of its constituent fibers (warp and / or weft).

[0049] The woven fabric may be any of plain weave, twill weave, satin weave, etc. Plain weave is preferred because it causes less misalignment of the weave when stretched diagonally.

[0050] The woven fabric of the present invention contains crimped yarns as at least a part of the constituent fibers, and the ratio of the crimped yarns to the total fibers constituting the woven fabric is is 2 It is 5 to 45 mass %.

[0051] The fibers (thread-like) constituting the woven fabric may also include fibers (thread-like) other than the crimped yarns. The other fibers are not particularly limited and can be selected from natural fibers, chemical fibers, and synthetic fibers. Synthetic fibers, especially polyester fibers, are preferred in terms of their resistance to plating.

[0052] It is desirable that the other fibers be used to form threads separate from the crimped yarns and interwoven when forming a woven fabric. For example, crimped yarns and threads made of other fibers may be inserted alternately as weft threads.

[0053] The woven fabric of the present invention contains crimped yarns in at least some of the warp and / or weft yarns. Both the warp and weft yarns may contain the crimped yarns, or only one of the warp and weft yarns may contain the crimped yarns. If the woven fabric uses crimped yarns in both the warp and weft yarns, the continuity of the yarns can be maintained in two directions, and therefore conductivity can be expected to be maintained regardless of the stretch direction.

[0054] The proportion of crimped yarns in the warp or weft constituting the woven fabric is not particularly limited, but it is preferable that the crimped yarns account for 10 to 100 mass %. The proportions of crimped yarns in the warp and weft may be the same or different.

[0055] When crimped yarns are used for the warp, the entire warp may be crimped yarns, or only a portion of the warp may be crimped yarns. It is preferable that 10 to 100% by mass of the warp yarns are crimped yarns. When crimped yarns are used for the weft, the entire weft may be crimped yarns, or only a portion of the weft may be crimped yarns. It is preferable that 10 to 100% by mass of the weft yarns are crimped yarns.

[0056] The fabric constituting the stretchable conductive fabric of the present invention is a woven fabric (highly stretchable fabric) containing crimped yarns in at least some of the warp and / or weft yarns, and can be made into a woven fabric (highly stretchable fabric) containing crimped yarns by weaving using the latent crimped multifilament yarn and then heat processing it. Methods for heat processing the woven fabric include immersing the fabric in hot water, and in this case, immersion in hot water (100°C) for 1 to 90 minutes is preferred, but is not particularly limited.

[0057] It is also possible to weave a fabric containing crimped yarns in at least some of the warp and / or weft yarns by previously heat-processing a latent crimped multifilament yarn.

[0058] The shrinkage percentage of the fabric (highly stretchable fabric) after heat processing is preferably 10 to 50%, although this depends on the ratio of crimped yarn to the total fibers constituting the fabric (highly stretchable fabric) containing crimped yarn. The heat shrinkage percentage of the fabric can be measured by JIS L1096 8.39 Method B (boiling water immersion method).

[0059] The stretchability of the highly stretchable fabric is not particularly limited, but the elongation (breaking elongation) in the direction of the warp and / or weft yarns at least partially containing crimped yarns (hereinafter referred to as "the direction of the warp and / or weft yarns at least partially containing crimped yarns") is preferably 30% or more, more preferably 30 to 90%. The elongation (breaking elongation) of the fabric in this invention is a value measured in accordance with JIS L1096 8.14 Method B (grab method), except that the sample width (grab width) was 10 mm.

[0060] The highly stretchable fabric preferably has a warp density of 50 to 200 threads / inch and a weft density of 40 to 200 threads / inch, and more preferably is a plain weave having such a weave density.

[0061] 2. Metallic coating The stretchable conductive fabric of the present invention is provided with a metal coating. The layer structure of the metal coating is not particularly limited, but it is preferably one or two layers. This prevents the coating from becoming too thick, maintains the texture of the fabric, and reduces manufacturing costs. When the metal coating is made up of two layers, the two layers may be formed using different methods using the same type of metal, or the two layers may be made of different metals.

[0062] Examples of metal species that can form the metal coating include copper, nickel, gold, silver, tin, zinc, iron, cobalt, etc. Among these, copper, silver, or copper and nickel (two-layer coating) are preferred.

[0063] The amount of metal applied to the metal coating is preferably 5 to 60 g / m 2 , more preferably 17 to 43 g / m 2 When two metal coating layers are formed, the thickness of the first metal coating layer is preferably 5 to 50 g / m 2 , more preferably 15 to 35 g / m 2 The thickness of the second metal coating is preferably 1 to 20 g / m 2 , more preferably 2 to 8 g / m 2 is.

[0064] 3. Stretchable conductive fabric The weight of the stretchable conductive fabric (fabric provided with a metal film) of the present invention is 40 to 230 g / m 2 It is preferable that the density is 40 to 170 g / m 2 It is more preferable that the amount of metal applied to the metal coating is 5 to 60 g / m. 2 It is preferable that the density is 17 to 43 g / m 2 The metal imparting rate of the metal coating is preferably 10 to 60 mass %, more preferably 17 to 45 mass %, based on the total mass of the stretchable conductive fabric.

[0065] The thickness of the stretchable conductive fabric of the present invention is preferably 0.10 to 0.65 mm, and more preferably 0.15 to 0.35 mm. The stretchable conductive fabric of the present invention has excellent stretchability, and the elongation (breaking elongation) in the warp and / or weft direction (i.e., at least one of the warp and weft directions) is preferably 30% or more, more preferably 30 to 90%. Note that the elongation (breaking elongation) of the fabric in the present invention is a value measured in accordance with JIS L1096 8.14 Method B (grab method), except that the sample width (grab width) was 10 mm.

[0066] The stress at 30% elongation in the warp and / or weft direction of the stretchable conductive fabric of the present invention (i.e., at least one of the warp direction and weft direction) is 10 N / cm or less, preferably 7 N / cm or less, and more preferably 5 N / cm or less. There is no particular lower limit for the stress at 30% elongation, but it is preferably 0.1 N / cm or more. Here, "warp and / or weft direction" refers to either the warp direction or the weft direction, or both.

[0067] More desirably, in at least one direction of the warp and / or weft yarns that contain at least a portion of crimped yarns (the direction of the warp and / or weft yarns that contain at least a portion of crimped yarns), the stress at 30% elongation is 10 N / cm or less, preferably 7 N / cm or less, and more preferably 5 N / cm or less.

[0068] The stress at 30% elongation indicates the ease of stretching of the fabric, with a lower value indicating greater stretchability. The stretchable conductive fabric of the present invention (after application of the metal coating) is particularly stretchable and therefore easy to handle, and does not require excessive stress when stretching, making it less likely for the metal coating to break.

[0069] The stress at extension is measured by elongating a sample using the same method and conditions as those for measuring the elongation at break, and reading the stress value at an intermediate stage before breakage. The stress at extension in this invention is a value measured in accordance with JIS L1096 8.14 Method B (grab method) except that the sample width and grip width are 10 mm, i.e., the value measured at a chuck distance of 100 mm, a sample width (grip width) of 10 mm, and a tensile speed of 150 mm / min.

[0070] The conductivity of the stretchable conductive fabric is not particularly limited, but it is preferable that the resistance value (electrode distance 50 mm) when unstretched is 0.001 to 100 Ω in at least one of the warp and weft directions, and that the increase rate of the resistance value when stretched 30% compared to the unstretched resistance value is +30% or less.

[0071] More preferably, in at least one direction of the warp and / or weft yarns that contain at least a portion of crimped yarns (the direction of the warp and / or weft yarns that contain at least a portion of crimped yarns), the resistance value when unstretched (electrode distance 50 mm) is 0.001 to 100 Ω, and the increase rate of the resistance value when stretched 30% relative to the unstretched resistance value is +30% or less.

[0072] That is, the stretchable conductive fabric of the present invention exhibits stable conductivity without a significant increase in resistance even when stretched, allowing it to maintain high conductivity. The unstretched resistance is measured using a milliohm tester with a sample width of 10 mm and an initial electrode distance of 50 mm. Resistance measurement during stretching can be performed by stretching the sample in the same manner as in the measurement of stress at stretching described above, and then contacting the measurement electrodes of the milliohm tester with the sample when a predetermined stretch rate is reached. For example, resistance at 30% stretching can be measured using a milliohm tester after stretching the sample in the same manner as in the measurement of stress at stretching, at the time of 30% stretching.

[0073] 4. Manufacturing method of stretchable conductive fabric The stretchable conductive fabric of the present invention can be produced by a method including a step of providing a metal coating on a highly stretchable fabric made of a woven fabric at least partially containing crimped yarn.

[0074] (1) Highly stretchable fabric manufacturing process By thermally processing the fabric obtained by weaving the above-mentioned latent crimped multifilament yarn, a highly stretchable fabric can be obtained from the fabric, at least in part, containing the crimped yarn. A method for thermally processing the fabric includes immersing the fabric in hot water. In this case, the fabric may be immersed in hot water (100°C) for 1 to 90 minutes, but is not limited to this.

[0075] The highly stretchable fabric of the present invention can also be obtained by thermally processing a latently crimped multifilament yarn beforehand and then forming a woven fabric. Preferably, a method is used in which a woven fabric is formed using a latently crimped multifilament yarn and then thermally processing the woven fabric.

[0076] The thickness of the highly stretchable fabric thus obtained (the fabric before the metal coating is applied) is not particularly limited, but is preferably 0.10 to 0.65 mm, more preferably 0.15 to 0.35 mm. When the highly stretchable fabric is a woven fabric, it preferably has a warp density of 50 to 200 threads / inch and a weft density of 40 to 200 threads / inch, and more preferably is a plain weave having such a weave density.

[0077] The stretchability of the obtained highly stretchable fabric is not particularly limited, but it is preferable that the elongation rate in at least one direction of the warp and / or weft is 30 to 60%.Furthermore, the stress at 30% elongation of the highly stretchable fabric is preferably 8 N / cm or less, and more preferably 5 N / cm or less.

[0078] (2) Metal coating process Methods for applying a metal coating to a highly stretchable fabric made of a woven fabric at least partially containing the crimped yarn of the present invention include vapor deposition, sputtering, electroplating, and electroless plating. Of these, electroplating and / or electroless plating are preferred. In consideration of the uniformity and conductivity of the metal coating, electroless plating or a combination of electroless plating and electroplating is particularly preferred.

[0079] When forming a single layer of metal film, it is preferable to use an electroless plating method. When forming a two-layer metal film, it is preferable to use a method that combines electroless plating and electroplating. When laminating two layers, two layers of the same metal may be laminated, or different metals may be laminated. Examples of metals used to apply the metal film include copper, nickel, gold, silver, tin, zinc, iron, and cobalt, and among these, copper, silver, or copper and nickel (two layers) are preferred.

[0080] A particularly preferred metal plating method in the present invention is a method in which two metal plating layers of copper and nickel are laminated by performing electroless copper plating followed by electrolytic nickel plating.

[0081] (3) Electroless plating The electroless plating treatment is carried out by a known method. After a pretreatment in which a highly stretchable fabric is applied with an electroless plating catalyst to activate it, the fabric is brought into contact with an electroless plating treatment solution containing a desired metal to deposit a metal film.

[0082] The electroless plating catalyst may be a solution containing metal ions that can be reduced to form a metal having plating catalytic activity. Examples of metals having plating catalytic activity include copper, nickel, silver, tin, rhodium, palladium, gold, and platinum, but palladium, which has high plating catalytic activity, is preferably used.

[0083] Palladium ions are particularly preferred as metal ions that can be reduced to metals with plating catalytic activity. Examples of compounds that generate palladium ions include palladium chloride, palladium bromide, palladium acetate, palladium sulfate, palladium nitrate, palladium acetylacetonate, and palladium oxide. Among these, palladium chloride, which is widely used as a general catalyst, is preferably used because it is relatively easy to obtain.

[0084] The solvent used for the metal ion-containing solution is not particularly limited, but is preferably water. The metal ion concentration in the metal ion-containing solution is preferably 10 to 80 g / L, and more preferably 20 to 50 g / L.

[0085] The reaction temperature when the highly stretchable fabric is brought into contact with the metal ion-containing solution is 10° C. to 80° C., preferably 10° C. to 50° C. The contact time with the metal ion-containing solution is preferably 10 to 800 seconds, more preferably 30 to 500 seconds.

[0086] After contacting the highly stretchable fabric with the metal ion-containing solution, it is preferable to wash the fabric with water to remove non-specifically attached metal ions. As the washing method, a known washing method can be used.

[0087] A preferred reduction method is to bring the fabric onto which metal ions have been adsorbed into contact with an acidic treatment solution containing a reducing agent (hereinafter referred to as a reducing treatment solution). Examples of reducing agents used in the acidic treatment solution include dimethylamine borane, sodium hypophosphite, hydrazine, diethylamine, ascorbic acid, and fluoroboric acid (tetrafluoroboric acid).

[0088] The reducing agent concentration in the reduction treatment solution is preferably 5 to 20 g / L. The solvent used in the reduction treatment solution is not particularly limited, but water is preferred. The pH of the reduction treatment solution is preferably 6 or less, more preferably 2 to 6, and even more preferably 3 to 5.9.

[0089] The highly stretchable fabric is contacted with the reduction treatment solution for 30 to 600 seconds, preferably 60 to 300 seconds. The contact temperature is 10 to 80°C, preferably 30 to 50°C. After contact with the reduction treatment solution, the fabric is washed with water to remove non-specifically attached reducing agent. After the reduction treatment, the fabric is washed and dried as necessary to obtain a fabric with plating catalytic activity.

[0090] As the electroless plating method, a known electroless plating method can be used. The metal for electroless plating is at least one metal selected from the group consisting of copper, nickel, tin, and silver, or an alloy thereof (e.g., an alloy of copper and tin). Copper and nickel are preferred, and copper is particularly preferred.

[0091] An existing plating bath can be used for electroless plating, and the fabric can be immersed in the plating bath. The reaction time and temperature for electroless plating can be adjusted appropriately depending on the plating film thickness, but the preferred plating time is 1 to 20 minutes and the preferred temperature is 30 to 50°C.

[0092] The metal coating formed by electroless plating is preferably a copper coating. The metal amount of the metal coating obtained by electroless plating is preferably 5 to 60 g / m 2 , more preferably 17 to 43 g / m 2 is.

[0093] After the electroless plating film is formed, the fabric can be washed with water as needed to remove non-specifically adhering plating solution.

[0094] (4) Electroplating When electroplating is performed after the electroless plating, a general electroplating method can be used. Nickel electroplating is preferably used as the electroplating method. The plating solution used in nickel electroplating can use a nickel sulfate solution as a metal source. Commercially available nickel electroplating solutions may also be used. Various surfactants, brighteners, antioxidants, etc. may be added to the electroplating solution.

[0095] The conditions for electroplating are not particularly limited as long as they are set within a range that allows the formation of a metal plating layer of the desired thickness. Typical conditions include a plating solution temperature of 20 to 40°C and a current density of 0.3 to 5.0 A / dm 2 The processing time can be set to 30 to 600 seconds.

[0096] The metal coating formed by electroplating is preferably a nickel coating. The metal amount of the metal coating obtained by electroplating is preferably 5 to 60 g / m 2 , more preferably 17 to 43 g / m 2 is. [Example]

[0097] The present invention will be described below with reference to examples, but the present invention is not limited to these examples in any way.

[0098] Example 1 (1) Filamentous To produce the fabric, the following yarns were prepared: a false-twisted yarn made of polyethylene terephthalate yarn (55.6 dtex / 36 filaments) as the warp yarn; and a latent crimped multifilament yarn (55.6 dtex / 36 filaments; manufactured by Chori Co., Ltd.) made of a side-by-side composite fiber of polyethylene terephthalate and polybutylene terephthalate as the weft yarn.

[0099] (2)High stretch fabric The multifilament yarn was used to produce a woven fabric (plain weave, warp density: 82 threads / inch, weft density: 52 threads / inch). The resulting fabric (plain weave) was immersed in hot water (100°C) for 5 minutes for thermal processing to form crimps. The proportion of crimped yarns to the total fabric was 39% by mass.

[0100] The stretchability (breaking elongation) of this fabric is 33% in the warp direction and 85% in the weft direction. The stress at 30% elongation of this fabric is 9.2 N / cm in the warp direction and 0.5 N / cm in the weft direction. In the present examples, the breaking elongation was measured using an Autograph (AG-IS) manufactured by Shimadzu Corporation at a sample width of 10 mm and a tensile speed of 150 mm / min. The stress at 30% elongation was measured using an Autograph (AG-IS) manufactured by Shimadzu Corporation at a sample width of 10 mm and a tensile speed of 150 mm / min.

[0101] (3) Formation of metal film The resulting fabric was immersed in a treatment solution containing 0.2 g / L of palladium chloride, 12.5 g / L of stannous chloride, and 250 ml / L of 36% hydrochloric acid at 20°C for 2 minutes, and then rinsed with water. The fabric was then immersed in 0.1 N hydrofluoric acid at 40°C for 2 minutes, and then rinsed with water. Next, the fabric was immersed in an electroless copper plating solution containing 8.2 g / L of copper chloride, 9 ml / L of 37% formalin, and 33 ml / L of 32% sodium hydroxide at 40°C for 3 minutes, and then rinsed with water.

[0102] Next, the plate was immersed in an electrolytic nickel plating solution containing 300 g / L of nickel sulfate, 30 g / L of sodium citrate, and a pH of 5.5 at 25°C for 3 minutes at a current density of 0.5 A / dm 2 After laminating nickel, the fabric was washed with water and dried to obtain a stretchable conductive fabric having two metal plating layers, a copper plating layer and a nickel plating layer, with a total thickness of 0.2 mm. The weight of the obtained stretchable conductive fabric was 75 g / m 2 The metal imparting rate of the metal coating to the total amount of the stretchable conductive fabric was 30 mass %.

[0103] (4) Evaluation of each physical property A micrograph (plan view) of the obtained stretchable conductive fabric is shown in Figure 1. This photograph was taken at a magnification of 140x using a digital microscope device (manufactured by HiROX Corporation).

[0104] The resulting stretchable conductive fabric had an elongation rate (breaking elongation) of 85% when stretched in the weft direction. The elongation rate (breaking elongation) was measured using an autograph (AG-IS) manufactured by Shimadzu Corporation, with a sample width (gripping width) of 10 mm and a pulling speed of 150 mm / min.

[0105] The stress at elongation was measured using an autograph (AG-IS) manufactured by Shimadzu Corporation, with the sample width (grip width) being 10 mm and the stretching speed being 150 mm / min in the weft direction, and the stress at 10%, 20%, 30% and 40% elongation was measured.

[0106] The resistance value of the obtained stretchable conductive fabric (at 40% elongation) was 0.30 Ω. The resistance values ​​at 0% elongation (initial value), 10% elongation, 20% elongation, and 30% elongation were also determined. The resistance values ​​were measured using a Hioki E.E. Corporation milliohm tester (RM-3545) with a sample width of 10 mm and an electrode distance of 50 mm (initial value). The results are shown in Table 1.

[0107] <Comparative Example> The same procedure as in Example 1 was carried out except that both the warp and weft yarns were false twist textured yarns made of polyethylene terephthalate yarn (55.6 dtex / 36 filaments). The results are shown in Table 1.

[0108] [Table 1] [Industrial Applicability]

[0109] The stretchable conductive fabric of the present invention has sufficient stretchability and can maintain high conductivity without the applied metal coating breaking due to stretching. It also has excellent flexibility and ability to follow shape changes such as bending. Such a stretchable conductive fabric of the present invention can be suitably used in wearable devices, electromagnetic wave shielding materials, sensor electrode materials, etc.

Claims

1. A stretchable conductive fabric comprising a woven fabric containing crimped yarns in at least some of the warp and / or weft yarns and having a metal coating applied thereto, characterized in that the ratio of crimped yarns to all fibers constituting the woven fabric is 25 to 45 mass %, and the stress at 30% elongation in at least one direction of the warp and / or weft yarns is 10 N / cm or less.

2. 2. The stretchable conductive fabric according to claim 1, characterized in that in at least one direction of the warp and / or weft, the increase in resistance value when stretched 30% relative to the resistance value when unstretched is +30% or less.

3. 2. The stretchable conductive fabric according to claim 1, wherein the crimped yarn is a composite fiber selected from the group consisting of a combination of polyethylene terephthalate resin and polybutylene terephthalate resin, a combination of polyethylene terephthalate resin and polytrimethylene terephthalate resin, and a combination of two polyethylene terephthalate resins having different physical properties, and the structure of the composite fiber is a side-by-side type or an eccentric core-sheath type.

4. A stretchable conductive fabric as described in claim 1, wherein the fabric containing crimped yarns in at least some of the warp and / or weft threads is a fabric containing crimped yarns in only one of the warp and weft threads.

5. The stretchable conductive fabric described in claim 1, wherein the shrinkage rate of the fabric after thermal processing is 10 to 50%.

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