conductive fabric

Abstract

The present invention aims to provide a conductive fabric that has sufficient electromagnetic shielding properties for practical use, excellent wrinkle resistance, and low surface gloss. [Solution] The conductive fabric of the present invention is a conductive fabric using metallized yarn for the warp and weft threads, wherein the conductive fabric has a weft tear strength of 14N or more, a cover factor of 1485 to 2310, and a basis weight of 35 to 70 g / m 2 Furthermore, the field shielding performance at 1 GHz is 43 dB or higher.

Description

[Technical Field]

[0001] This invention relates to a conductive fabric using metallized threads as both warp and weft threads. [Background technology]

[0002] To reduce the impact of electromagnetic noise generated by electronic devices, cables, motors, and inverters on other electronic devices, various sheet-like materials with electromagnetic shielding properties have been proposed. For example, these include fabrics made from ultra-fine metal wires, fabrics coated with conductive resin, and fabrics plated with metal by electroless plating. Fabrics plated with metal are lightweight and flexible, and are used, for example, as electromagnetic shielding aprons for office automation equipment and as electromagnetic shielding between computer casings.

[0003] Regarding materials in which metal plating is applied to woven fabrics, fabrics with properties other than electromagnetic wave shielding have been proposed. For example, Patent Document 1 describes that by applying metal plating to a woven fabric to cover the entire surface with a metal layer, and then applying resin processing on top of that to provide thermoplastic resin to the voids between the threads of the fabric, an electromagnetic wave shielding sheet can be obtained with improved shape retention in addition to electromagnetic wave shielding properties. Furthermore, Patent Documents 2 and 3 describe electromagnetic wave shielding fabrics in which metal plating is applied to woven fabrics with specific ranges of thread fineness and fabric cover factor, or to woven fabrics using flat cross-section threads, resulting in fabrics with fewer gaps between the threads, a smooth surface, and excellent texture in addition to electromagnetic wave shielding properties.

[0004] However, electromagnetic shielding materials made by applying metal plating to fabrics tend to have smooth surfaces, which is thought to be the reason why they are prone to creases and wrinkles when folded. Such creases and wrinkles are thought to affect the electromagnetic shielding properties. Also, when the surface is smooth, the glossiness due to the metal plating is enhanced, resulting in a highly glaring appearance. Therefore, the electromagnetic shielding materials described in Patent Documents 1 to 3 required further improvement in terms of wrinkle resistance and glossiness. Furthermore, the electromagnetic shielding sheet described in Patent Document 1 has a resin layered on top of a metal layer and fills the gaps between threads, which reduces contact between metals on the sheet and lowers conductivity. While this provides excellent shape retention, it is also very prone to creases and wrinkles. In addition, the woven fabrics described in Patent Documents 2 and 3 have improved surface smoothness, so the woven fabrics after metal plating have an even stronger glossiness. This makes them unsuitable for applications where a low glossiness is preferable for electromagnetic shielding materials. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2010-98006 [Patent Document 2] Japanese Patent Publication No. 2000-303302 [Patent Document 3] Japanese Patent Publication No. 2002-20941 [Overview of the project] [Problems that the invention aims to solve]

[0006] This invention has been made in view of the above problems, and aims to provide a conductive fabric that has sufficient electromagnetic shielding properties for practical use, excellent wrinkle resistance, and low surface gloss. [Means for solving the problem]

[0007] The inventors of the present invention conducted diligent research to solve the above problems and, as a result, discovered that by using pre-metallized yarns for the warp and weft threads, and creating a fabric with a specific cover factor and weight, it is possible to obtain a conductive fabric that has sufficient electromagnetic shielding properties for practical use, excellent wrinkle resistance, and low surface gloss, leading to the present invention.

[0008] In other words, the present invention provides the invention in the following aspects. <1> A conductive fabric in which threads with a metallized surface are used as warp and weft threads, The aforementioned conductive fabric has a transverse tear strength of 14N or more, a cover factor of 1485-2310, and a basis weight of 35-70 g / m². 2 A conductive fabric having an electric field shielding performance of 43 dB or more at 1 GHz. <2> The aforementioned metallized yarn is a yarn in which the surface of a synthetic fiber is silver-plated or silver-coated. <1> The conductive fabric described above. <3> The conductive fabric has an elongation rate of 30% or more in at least one of the warp and weft directions. <1> or <2> The conductive fabric described above. <4> The conductive fabric is a ripstop fabric having a base fabric, warp ribs, and weft ribs. The warp and weft ridges are formed by aligning 2 to 6 threads with a metallized surface. <1> ~ <3> A conductive fabric as described in any of the following. [Effects of the Invention]

[0009] The conductive fabric of the present invention possesses sufficient electromagnetic shielding properties for practical use, while also exhibiting excellent wrinkle resistance and low surface gloss. Furthermore, the conductive fabric of the present invention is lightweight yet possesses high tear strength. Moreover, even when stored in high-temperature and high-humidity environments, the conductive fabric of the present invention is less prone to deterioration of electromagnetic shielding properties and less prone to discoloration of the fabric surface.

[0010] Since the conductive fabric of the present invention is lightweight, it can be suitably used for the housing of equipment that generates electromagnetic waves and electromagnetic shielding aprons, and can also be used in large-scale measurement instrument laboratories, buildings, factory buildings, tents, etc. In addition, since the conductive fabric of the present invention has a low surface glossiness, there is little glare in appearance and it is possible to suppress a decrease in visibility, and it can be suitably used outdoors. Furthermore, since the conductive fabric of the present invention is excellent in wrinkle resistance and has a good appearance, it can be suitably used for clothing having electromagnetic shielding properties and various other applications.

Brief Description of Drawings

[0011] [Figure 1] It is a schematic diagram showing an embodiment (butcher weave) of the weave structure of the conductive fabric of the present invention. [Figure 2] It is a schematic diagram showing an embodiment (ripstop weave) of the weave structure of the conductive fabric of the present invention. [Figure 3] It is a schematic diagram showing the weave structure (ripstop weave) of the conductive fabric obtained in Example 1 of the present invention. [Figure 4] It is a schematic diagram showing the weave structure (plain weave) of the conductive fabric obtained in Comparative Example 1 of the present invention. [Figure 5] It is a photograph of the conductive fabric obtained in Example 1 of the present invention after applying a rubbing action. [Figure 6] It is a photograph of the conductive fabric obtained in Comparative Example 1 of the present invention after applying a rubbing action.

Modes for Carrying Out the Invention

[0012] Hereinafter, the present invention will be described in detail.

[0013] The conductive fabric of the present invention is formed by using yarns with metallized surfaces as warp yarns and weft yarns. That is, the conductive fabric of the present invention is not one in which the entire fabric is subjected to metal plating or metal coating after forming the fabric, but is formed by using yarns with metallized surfaces as warp yarns and weft yarns in advance. <00001 / 01> [Thread with a metallic surface] Examples of threads with a metallized surface include threads whose surface is plated or coated with metal. Examples of metals used for plating or coating include nickel, iron, cobalt, gold, silver, tin, and palladium. These metals may be used individually or as an alloy of two or more types. The plating or coating may also consist of layers of two or more metals. Of these metals, silver is preferred because it is less susceptible to deterioration such as oxidation, is more chemically stable than copper or nickel, and is more cost-effective than gold or platinum.

[0015] There are no particular restrictions on the metal plating method, and known methods such as electroless plating, a combination of electroless plating and electroplating, and dry plating can be used. The thickness of the metal plated onto the thread is not particularly limited and can be appropriately adjusted within the range of 0.01 to 20 μm (from extremely thin to extremely thick in plating terminology) from the viewpoint of electromagnetic shielding properties, etc.

[0016] Examples of threads whose surfaces are metallized include synthetic fibers such as polyamide fibers, polyester fibers, and acrylic fibers; synthetic resins such as polypropylene, polyethylene, and vinyl chloride; natural fibers such as cotton and wool; regenerated fibers such as acetate fibers and viscose fibers; and inorganic fibers such as glass fibers and carbon fibers. Of these, synthetic fibers are preferred, and polyamide fibers are more preferred, from the viewpoint of heat resistance and strength.

[0017] The metallized surface yarn is preferably a synthetic fiber yarn in which the surface is silver-plated or silver-coated, more preferably a polyamide fiber yarn in which the surface is silver-plated or silver-coated, and even more preferably a polyamide fiber yarn in which the surface is silver-plated.

[0018] The yarn whose surface is metallized may be any of the following: monofilament yarn or multifilament yarn made of long fibers, or spun yarn made of short fibers.

[0019] Furthermore, since electromagnetic shielding materials are used near electronic equipment and power lines, as well as in civil engineering and construction applications, and in automotive applications, flame retardancy is sometimes required in addition to electromagnetic shielding performance. Therefore, from the viewpoint of further imparting flame retardancy to the conductive fabric of the present invention, flame-retardant fibers can be used as threads whose surfaces are metallized. Examples of flame-retardant fibers include those that have inherent flame retardancy, such as aramid fibers and polyvinyl chloride; and fibers that have been processed by kneading in flame retardants, such as flame-retardant polyester fibers and flame-retardant vinylon fibers.

[0020] From the viewpoint of imparting appropriate stretchability to the conductive fabric of the present invention, the metallized surface yarn preferably has an elongation rate of 10% or more, and more preferably 11 to 30%. A yarn with an elongation rate of 10% or more and that has swelling or crimp in the yarn itself is preferable because it can impart swelling, softness, and better wrinkle resistance to the conductive fabric. Furthermore, although it is thought that the smoothness of the fabric surface and the diffuse reflection of light are reduced and the aforementioned yarn is increased compared to when a straight yarn without crimp (for example, raw silk) is used, it is possible to form a fabric with a lower surface gloss. The metallized surface yarn with an elongation rate of 10% or more is not particularly limited, but examples include a crimped yarn obtained by applying false twist crimp processing to a metal-plated surface yarn, and a metal-plated denite yarn. From the viewpoint of easily retaining the metal layer on the surface of the yarn, a metal-plated denite yarn is preferred. Denite yarn will be described later. In the present invention, the elongation rate of a metallized surface yarn refers to the elongation rate of the raw yarn used to construct a conductive fabric, and is a value measured according to "Method B (when measuring with 10 strands bundled together)" of "8.11 Elasticity" in JIS L 1013:2010 (Test method for chemical fiber filament yarn).

[0021] The metallized surface yarn preferably has a total fineness of 20 to 330 dtex, more preferably 25 to 250 dtex. The single fiber fineness is preferably 0.1 to 6 dtex, more preferably 1.2 to 6 dtex, even more preferably 2.5 to 6 dtex, and particularly preferably 3.5 to 6 dtex. When the fineness of the metallized surface yarn is within the above range, a conductive fabric with a coverage factor and basis weight within a specific range, as described later, can be made to a certain degree of high density, further improving the electromagnetic shielding properties of the conductive fabric.

[0022] [Composition and properties of conductive fabrics] The conductive fabric of the present invention is formed using metallized surface yarns as warp and weft threads. From the viewpoint of electromagnetic wave shielding properties, the content of metallized surface yarns is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and particularly preferably 100% by mass, relative to the entire fabric. That is, it is particularly preferable that the entire fabric is formed of metallized surface yarns. Furthermore, the content of metallized surface yarns in each of the warp and weft threads can be adjusted as appropriate. For example, it is preferable that both the warp and weft threads contain 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and particularly preferably 100% by mass. In addition, other yarns besides metallized surface yarns may be included as long as they do not impair the effects of the present invention. Examples of other yarns include the metallized surface yarns exemplified above.

[0023] The conductive fabric of the present invention has a certain degree of density, and its cover factor (hereinafter sometimes referred to as "CF") calculated by the following formula (1) is 1485 to 2310, preferably 1485 to 2200, and more preferably 1500 to 2100. If the CF is less than 1485, the density of the fabric is low, resulting in poor electromagnetic shielding properties. On the other hand, if the CF exceeds 2310, the constraints imposed by the weave points of the fabric become too strong, which tends to reduce the tear strength of the fabric. In the present invention, the CF can be adjusted to the above range by reducing the fineness of the metallized yarn or by adjusting the weave structure.

[0024] CF is a numerical representation of the density of a fabric, and is calculated using the following formula (1). CF = WAD × DTA 1 / 2 +WED×DTE 1 / 2 (1) DTA: Fineness (dtex) of the warp multifilament. DTE: Fineness (dtex) of the weft multifilament. WAD: Warp thread density (threads / 2.54cm) WED: Weft density (threads / 2.54cm)

[0025] The fineness of multifilament yarn is measured and calculated according to the method specified in "8.3.1 True Fineness" of JIS L-1013:2010 (Test Methods for Chemical Fiber Filament Yarns). Furthermore, in a square enclosed by 2.54 cm in the warp direction and 2.54 cm in the weft direction of any conductive fabric, the average fineness of all warp multifilament yarns is defined as DTA, and the average fineness of all weft multifilament yarns is defined as DTE. In addition, the warp density and weft density are measured and calculated according to "Method A (JIS Method)" of "8.6.1 Density of Fabrics" of JIS L 1096:2010 (Test Methods for Woven and Knitted Fabrics). Note that both warp density and weft density refer to the finished weave density.

[0026] When obtaining a textile with electromagnetic shielding properties by applying metal plating after forming the fabric, if metal plating is applied to a high-density fabric, a metal layer is formed on the surface of the fabric. However, the plating solution does not spread to the entire surface of the individual threads, and the metal layer tends not to form on the entire surface of the individual threads. As a result, contact between the threads of the fabric with the metal layer is reduced, and the electromagnetic shielding properties tend to be inferior. On the other hand, the conductive textile of the present invention is formed using threads with pre-metallized surfaces as warp and weft threads. Therefore, when a high-density fabric that satisfies the above-mentioned specific range of CF is made, contact between the metal layers increases, and furthermore, slippage between threads is less likely to occur, resulting in improved conductivity and excellent electromagnetic shielding properties.

[0027] The conductive fabric of the present invention preferably has moderate stretchability, and preferably has an elongation rate of 30% or more in at least one of the warp and weft directions of the fabric, more preferably 32% or more, even more preferably 35% or more, and particularly preferably 36% or more. In the present invention, elongation rate means elongation at break, and is a value measured according to "Method A (strip method)" of "8.14.1 JIS method" of JIS L 1096:2010 (Test methods for woven and knitted fabrics), under the conditions of a test piece of 50 mm × 300 mm, a gripping distance of 200 mm, and a tensile speed of 200 mm / min. The upper limit of the elongation rate is within a range that does not impair the effects of the present invention, that is, a range in which excessive stretching of the fabric does not cause peeling or detachment of the metal plating or metal coating, or a range in which there is no significant decrease in electromagnetic wave shielding performance, for example, 60% or less, preferably 50% or less, more preferably 45% or less, and particularly preferably 40% or less. If the elongation rate in at least one of the warp and weft directions of the fabric is 30% or more, then, for example, when used as an electromagnetic wave shielding material for tents, clothing, etc., the threads constituting the fabric will not easily break even when tension is applied to the fabric, resulting in excellent handling. Furthermore, because the conductive fabric of the present invention uses threads with a metallized surface for both the warp and weft, when tension is applied to the fabric, the metal plating on the thread surface is less likely to peel or fall off compared to conventional conductive fabrics in which metal plating is applied after the fabric is formed, effectively suppressing a decrease in electromagnetic wave shielding performance. In the present invention, the elongation rate of the fabric can be improved by using crimpable threads, particularly denite threads, as the threads with a metallized surface. In addition, the elongation rate can be adjusted to the desired range by adjusting the CF and weave structure of the fabric.

[0028] When stretching is applied to a woven fabric, changes occur such as the movement of the fabric's structure points, the movement of the threads, and the physical stretching of the threads themselves. Conventional conductive woven fabrics, obtained by applying metal plating after the fabric is formed, have a metal layer formed only on the surface of the fabric. Therefore, when stretching is applied, the above changes in the fabric cause cracks in the metal layer, making it easier for the metal plating to peel off or fall off from the fabric surface. As a result, even if the fabric has excellent electromagnetic shielding properties in its initial state without stretching, if strong stretching is applied temporarily or if the stretched state is prolonged, the electromagnetic shielding properties of the conductive woven fabric may decrease. On the other hand, the conductive woven fabric of the present invention is formed using threads with pre-metallized surfaces for both the warp and weft threads. Therefore, even if the above changes occur in the fabric during stretching, peeling or detachment of the metal plating on the thread surface is less likely to occur. As a result, the electromagnetic shielding properties of the conductive woven fabric of the present invention do not easily decrease even when the fabric is stretched.

[0029] The conductive fabric of the present invention has a weft tear strength of 14N or more, preferably 15N or more, more preferably 16N or more, even more preferably 17N or more, and particularly preferably 18N or more. The upper limit of the weft tear strength is within a range that does not impair the effects of the present invention, for example, 50N or less, preferably 40N or less, and more preferably 35N or less. The warp tear strength is not particularly limited, but for example, 12N or more, preferably 15N or more, and more preferably 16N or more. The upper limit of the warp tear strength is, for example, 50N or less, preferably 40N or less, and more preferably 35N or less. Furthermore, the sum of the weft tear strength and the warp tear strength is, for example, 26N or more, preferably 30N or more, and more preferably 33N or more. The upper limit of the sum of the tear strength in the weft direction and the tear strength in the warp direction is, for example, 100 N or less, preferably 80 N or less. In the present invention, the tear strength is a value measured according to "8.17.4 Method D (pendulum method)" of JIS L 1096:2010 (Test methods for woven and knitted fabrics). In the present invention, the tear strength in the weft and warp directions can be adjusted to the above range by adjusting the type and fineness of the yarn, the weave structure, or by adjusting the CF.

[0030] The conductive fabric of the present invention has sufficient electromagnetic shielding properties for practical use, with an electric field shielding performance of 43 dB or more at 1 GHz, preferably 45 dB or more, more preferably 48 dB or more, and even more preferably 50 dB or more. If the electric field shielding performance at 1 GHz is 43 dB or more, it will have an excellent effect in shielding noise caused by electromagnetic waves in the high-frequency and low-frequency ranges. In the present invention, the electric field shielding performance can be adjusted to the above range by using yarn with a metallized surface in advance for the warp and weft threads, and by making the CF within the specified range, thereby creating a conductive fabric with a certain degree of density.

[0031] The conductive fabric of the present invention preferably has a magnetic field shielding property of 20 dB or more, more preferably 25 dB or more, and even more preferably 30 dB or more at 1 GHz. If the magnetic field shielding property at 1 GHz is 20 dB or more, the effect of shielding noise caused by electromagnetic waves in the low-frequency range will be excellent. In the present invention, by using yarns whose surfaces are metallized in advance as warp yarns and weft yarns, and by using CF within the specific range, etc., to make a conductive fabric with a certain degree of high density, etc., the magnetic field shielding property can be adjusted within the above range.

[0032] From the perspective of lightness, the conductive fabric of the present invention is preferably as thin as possible. Therefore, the fabric weight is 35 - 70 g / m 2 and preferably 40 - 65 g / m 2 more preferably 40 - 60 g / m 2 even more preferably 45 - 60 g / m 2 particularly preferably 50 - 60 g / m 2 If the fabric weight is 35 - 70 g / m 2 it is excellent in lightness and has sufficient tensile strength and tear strength for practical use. Therefore, it is easy to handle when used as clothing or a tent having electromagnetic wave shielding properties. In the present invention, the fabric weight is a value measured according to "A method (JIS method)" of "8.3.2 Mass per unit area in standard state" in JIS L 1096:2010 (Test methods for fabrics and knitted fabrics).

[0033] The number of warp yarns of the conductive fabric of the present invention is preferably 90 - 180 yarns / 2.54 cm, more preferably 90 - 160 yarns / 2.54 cm, even more preferably 100 - 150 yarns / 2.54 cm, and particularly preferably 120 - 150 yarns / 2.54 cm. Also, the number of weft yarns of the conductive fabric of the present invention is preferably 90 - 200 yarns / 2.54 cm, more preferably 100 - 190 yarns / 2.54 cm, even more preferably 110 - 180 yarns / 2.54 cm, and particularly preferably 120 - 170 yarns / 2.54 cm.

[0034] The weave structure of the conductive fabric of the present invention is not particularly limited, but it is preferable that the weave structure does not make the fabric thick, and that it is a single-ply fabric that is not a double or triple-ply weave structure. When the weave structure of the conductive fabric of the present invention is a single-ply weave structure that is not a double-ply weave, examples include plain weave, twill weave, satin weave, etc. Furthermore, in order to make the conductive fabric of the present invention even more tear-strength, it is preferable that it be a butcher weave or ripstop fabric.

[0035] When the conductive fabric of the present invention is a butcher weave or ripstop fabric, it is preferable that it has a base weave, warp ribs, and weft ribs. Furthermore, it is preferable that the warp ribs and weft ribs are formed by drawing together 2 to 6 threads with a metallized surface. That is, the warp threads, which are drawn together in 2 to 6 strands, and the weft threads, which are drawn together in 2 to 6 strands, are arranged at intervals in the warp and weft directions of the fabric, and there are portions where the warp ribs and weft ribs intersect. The number of such intersecting portions is preferably 2 or more per 2.54cm × 2.54cm, more preferably 3 or more per 2.54cm × 2.54cm, and even more preferably 4 or more per 2.54cm × 2.54cm. The upper limit of the number of such intersecting portions is, for example, 30 or less per 2.54cm × 2.54cm. In this case, the total fineness of the surface-metallized yarn used in the base fabric is preferably 20 to 330 dtex, and the total fineness of the surface-metallized yarn used in the warp and weft ribs may be the same as or greater than that of the yarn used in the base fabric.

[0036] The intersecting portion is indicated by reference numeral 1 in Figures 1 and 2. Any combination of threads can be used for the number of threads to be joined, such as 2 warp threads × 2 weft threads, 2 warp threads × 3 weft threads, 3 warp threads × 2 weft threads, or 3 warp threads × 3 weft threads.

[0037] The conductive fabric of the present invention preferably has a surface gloss of 3.0 or less, more preferably 2.5 or less, and even more preferably 2.0 or less. When the surface gloss is 3.0 or less, the gloss is sufficiently low, which reduces the glare of the fabric's appearance and suppresses a decrease in visibility. Therefore, it has the advantage of being suitable for outdoor use. In the present invention, the surface gloss is a value measured by the method described in the examples.

[0038] The conductive fabric of the present invention exhibits excellent wrinkle resistance, and creases and wrinkles are less likely to remain when folded. Therefore, the conductive fabric of the present invention can suppress the reduction in electromagnetic wave shielding performance due to wrinkles, and also has a superior appearance. When the wrinkle resistance is tested in accordance with JIS L1059-2:2009 (Test method for wrinkle resistance of textile products - Part 2: Appearance evaluation after creasing (wrinkle method)), it is preferable that the judgment is grade 3 or higher. The conductive fabric of the present invention has excellent wrinkle resistance because the fabric becomes softer by using yarn with a specific or higher stretch elongation rate, i.e., a bulge due to crimping.

[0039] The conductive fabric of the present invention exhibits minimal changes in electromagnetic shielding properties and appearance even after storage in high-temperature and high-humidity environments compared to before storage. In the case of conventional electromagnetic shielding fabrics obtained by metal plating after fabric formation, discoloration and uneven coloring can occur on the fabric surface even when used in a normal temperature environment, which is thought to be due to oxidation of the plated metal or oily stains adhering to the metal plating surface. Furthermore, there were concerns about a decrease in electromagnetic shielding properties as a result. On the other hand, the conductive fabric of the present invention, by employing the manufacturing method described later, is presumed to be due to the formation of an oxide film (passivation film) over the entire surface of the fabric. As a result, it exhibits minimal discoloration of the fabric surface and a low decrease in electromagnetic shielding properties even after storage not only in a normal temperature environment but also in a high-temperature and high-humidity environment. Therefore, the conductive fabric of the present invention is suitable for long-term storage and use.

[0040] The conductive fabric of the present invention preferably exhibits a small change in conductivity (resistivity) after storage at 70°C × 90%RH for 168 hours, as an indicator of minimal impact on electromagnetic shielding properties. Specifically, the change rate (absolute value) is preferably 15% or less, more preferably 10% or less, even more preferably 5% or less, and particularly preferably 2% or less. In the present invention, resistivity is the value measured by the method described in the examples. Generally, electromagnetic shielding materials are considered to have better electromagnetic shielding properties if they have superior conductivity. Therefore, the conductive fabric of the present invention preferably has low resistance values ​​both in its initial state and after storage at 70°C × 90%RH for 168 hours, from the viewpoint of electromagnetic shielding properties. Specifically, it is preferably 10.0 Ω·cm or less, more preferably 5.0 Ω·cm or less, and even more preferably 2.5 Ω·cm or less. The lower limit of the resistance value is not particularly limited, but for example, 1.0 × 10 -6 It is greater than Ω·cm and 1.0 × 10 -4 It may be Ω·cm or greater, or 1.0Ω·cm or greater.

[0041] [Method for manufacturing conductive fabrics] Next, the method for producing the conductive fabric of the present invention will be described. The conductive fabric of the present invention is obtained by weaving using the aforementioned surface-metallized yarn as both the warp and weft threads. The surface-metallized yarn is not particularly limited, but from the viewpoint of improving wrinkle resistance and producing a fabric with low gloss, it is preferable to use denit yarn. Denit yarn is a yarn that has crimp properties, obtained by first knitting the yarn in a tube, then applying heat treatment, and then unraveling the tubular knitted fabric to return it to a yarn state. In the present invention, it is preferable to use yarn obtained by tubular knitting the yarn before its surface is metallized, then applying metallization (metal plating or metal coating) and heat treatment to the tubular knitted fabric, and then unraveling the tubular knitted fabric. The conductive fabric of the present invention, woven using surface-metallized denit yarn as both the warp and weft threads, has an appropriate elongation rate as described above due to the crimping of the denit yarn, as well as fullness and softness, and furthermore, excellent wrinkle resistance. Furthermore, the conductive fabric of the present invention, woven using metallized denite yarns for both the warp and weft, has a lower surface smoothness than a fabric woven using straight, non-crimped yarns for both the warp and weft. Therefore, the conductive fabric of the present invention has a low surface gloss, which is thought to be due to increased diffuse reflection of light.

[0042] It is preferable that the fabric obtained by weaving using the aforementioned surface-metallized yarn as both warp and weft threads be further heat-treated. The heat treatment conditions can be appropriately adjusted depending on the type of yarn whose surface is metallized and the type of metal used. For example, when using silver-plated or silver-coated polyamide yarn, the heat treatment temperature is preferably 150 to 200°C, and the heat treatment time is preferably 30 seconds to 3 minutes. Conventional electromagnetic shielding fabrics were manufactured by first heat-treating the fabric to impart shape and dimensional stability to the fabric, and then applying metal plating to the heat-treated fabric. On the other hand, it is preferable that the conductive fabric of the present invention be manufactured by weaving using the aforementioned surface-metallized yarn as both warp and weft threads to obtain a fabric, and then heat-treating the obtained fabric. It is presumed that this manufacturing method will uniformly form an oxide film (non-conductive film) over the entire surface of the fabric. As a result, the conductive fabric of the present invention, when used as an electromagnetic wave shielding material, is less prone to oxidation of metals or discoloration of the fabric surface due to oily stains adhering to metal plating or metal coating surfaces, and also has the characteristic of not being prone to a decrease in electromagnetic wave shielding performance (i.e., the change in resistivity is small). [Examples]

[0043] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0044] <Measurement and Evaluation>

[0045] (a) CF (Coverage Factor) CF was calculated using the following formula (1). CF = WAD × DTA 1 / 2 +WED×DTE 1 / 2 (1) DTA: Fineness (dtex) of the warp multifilament. DTE: Fineness (dtex) of the weft multifilament. WAD: Warp thread density (threads / 2.54cm) WED: Weft density (threads / 2.54cm) The fineness of the multifilament yarn was measured and calculated according to the method specified in "8.3.1 True Fineness" of JIS L-1013:2010 (Test Methods for Chemical Fiber Filament Yarns). Furthermore, in a square enclosed by 2.54 cm in the warp direction and 2.54 cm in the weft direction of the obtained conductive fabric, the average fineness of all warp multifilaments was defined as DTA, and the average fineness of all weft multifilaments was defined as DTE. The warp and weft densities were measured and calculated according to "Method A (JIS Method)" of "8.6.1 Density of Fabrics" of JIS L 1096:2010 (Test Methods for Woven and Knitted Fabrics). Note that both warp and weft densities refer to the finished weave density.

[0046] (b) Inspector The basis weight was measured using the obtained conductive fabric according to "Method A (JIS method)" of "8.3.2 Mass per unit area under standard conditions" in JIS L 1096:2010 (Test methods for woven and knitted fabrics).

[0047] (c) Tear strength The tear strength in the weft and warp directions was measured using the obtained conductive fabric according to "8.17.4 Method D (Pendulum Method)" of JIS L 1096:2010 (Testing Methods for Woven and Knitted Fabrics).

[0048] (d) Growth rate The obtained conductive fabric was cut into 50 mm x 300 mm pieces and used as test specimens. The elongation at break in the warp and weft directions was measured according to "Method A (Strip Method)" of "8.14.1 JIS Method" of JIS L 1096:2010 (Test Methods for Woven and Knitted Fabrics), under conditions of a gripping distance of 200 mm and a tensile speed of 200 mm / min.

[0049] (e) Electromagnetic shielding properties Using the obtained conductive fabric, the electric field shielding and magnetic field shielding properties (unit: dB) were measured using the KEC method (KEC: abbreviation for "Kansai Electronics Industry Promotion Center") in the frequency range of 100 MHz to 1 GHz, and the value at 1 GHz was adopted for both.

[0050] (f) Surface gloss The obtained conductive fabric was cut into 400mm x 400mm pieces and used as test specimens. Light was shone onto the test specimens from a direction perpendicular to the specimen and at a 45° angle to the plane, and the intensity of light diffusely reflected perpendicular to the incident light was measured. The measurement was performed using a digital angle-shifting gloss meter UGV-5D (manufactured by Suga Test Instruments Co., Ltd., incident angle: 45°, receiving angle: 45°).

[0051] (g) Wrinkle-resistant Using the obtained conductive fabric, the appearance of the fabric after creasing was visually evaluated according to the method described in Section 9 of JIS L1059-2:2009 (Test method for wrinkle resistance of textile products - Part 2: Appearance evaluation after creasing (wrinkle method)), and was classified from Grade 5 (smoothest appearance) to Grade 1 (most wrinkled appearance).

[0052] (h) Resistivity and rate of change The obtained conductive fabric was cut into 50 mm x 80 mm pieces and used as test specimens. The initial resistivity was measured in an environment of 23°C x 50% RH according to JIS K 7194-1994 (Resistivity Test Method for Conductive Plastics using the 4-Probe Method). Next, the test specimens were stored in an environment of 70°C x 90% RH for 168 hours, and then the resistivity was measured again in an environment of 23°C x 50% RH. Three test specimens were prepared for measurement, and five measurements were taken for each specimen. The average value was adopted as the resistivity. The rate of change (absolute value) between the initial resistivity and the resistivity after storage in a high-temperature, high-humidity environment was calculated using the following formula. Rate of change (%) = [(Resistivity after storage in a high-temperature, high-humidity environment - Initial resistivity) / Initial resistivity] × 100

[0053] (i) Evaluation of discoloration after storage in a high temperature and high humidity environment The obtained conductive fabric was cut into 400mm x 400mm sections to serve as samples. After storing the samples at 70°C x 90%RH for 168 hours, the change in color tone compared to before storage was evaluated by sensory assessment according to the following criteria. <Evaluation Criteria> ○: Less discoloration. ×: The discoloration is significant.

[0054] (Example 1) As a yarn with a metallized surface, a denied yarn of silver-plated nylon multifilament with a density of 33 dtex / 7 filaments (the stretch elongation rate measured according to "Method B" of "8.11 Stretchability" in JIS L 1013:2010 was 14.5%. Hereinafter referred to as "silver-plated nylon yarn") was prepared. Next, after warping the silver-plated nylon yarn to form the ripstop structure shown in Figure 3, the warp beam was set up in an air-jet loom (manufactured by Ishikawa Seisakusho Co., Ltd.), and silver-plated nylon yarn was also used as the weft yarn. The fabric was woven so that the warp yarns (arrangement b) and weft yarns (arrangement b) made of two strands of silver-plated nylon yarn were arranged at regular intervals, thereby obtaining a ripstop fabric. Furthermore, the obtained fabric was run through a heat treatment machine (oven) with an internal temperature of 170°C, and the surface of the fabric was heat-treated at 170°C for 1 minute to obtain a conductive fabric.

[0055] (Example 2) A twill weave fabric was obtained in the same manner as in Example 1, except that the warp and weft densities were changed as shown in Table 1 and a 2 / 1 twill weave structure was adopted. Furthermore, the obtained fabric was passed through a heat treatment machine (oven) with an internal temperature of 170°C to perform a heat treatment on the fabric surface at 170°C for 1 minute to obtain a conductive fabric.

[0056] (Example 3) A ripstop fabric was obtained in the same manner as in Example 1, except that the warp and weft densities were changed as shown in Table 1. Furthermore, the obtained fabric was passed through a heat treatment machine (oven) with an internal temperature of 170°C to perform a heat treatment on the fabric surface at 170°C for 1 minute to obtain a conductive fabric.

[0057] (Comparative Example 1) Nylon multifilament A with 33 dtex / 10 filaments (stretch elongation rate measured according to Method B of JIS L 1013:2010, "8.11 Stretchability" is 7%) and nylon multifilament B with 55 dtex / 15 filaments (stretch elongation rate measured according to Method B of JIS L 1013:2010, "8.11 Stretchability" is 7%) were prepared. Next, to obtain the plain weave structure shown in Figure 4, nylon multifilament A (arrangement c) and nylon multifilament B (arrangement d) were warped, the warp beams were set up in an air jet loom (manufactured by Ishikawa Seisakusho Co., Ltd.), and nylon multifilament A (arrangement c) and nylon multifilament B (arrangement d) were also used as weft threads to obtain a plain weave fabric. To impart dimensional and shape stability to the obtained raw fabric, it was heat-treated at 170°C for 1 minute in the same manner as in Example 1, and then silver plating was applied to the entire surface of the fabric by electroplating to obtain a conductive fabric.

[0058] (Comparative Examples 2 and 3) A ripstop fabric was obtained in the same manner as in Example 1, except that the warp and weft densities were changed as shown in Table 1. Furthermore, the obtained fabric was passed through a heat treatment machine (oven) with an internal temperature of 170°C to perform a heat treatment on the fabric surface at 170°C for 1 minute to obtain a conductive fabric.

[0059] Table 1 shows the measurement and evaluation results for the conductive fabrics obtained in Examples 1-3 and Comparative Examples 1-3.

[0060] [Table 1]

[0061] The conductive fabrics obtained in Examples 1-3 exhibited electromagnetic shielding properties equivalent to or better than conventional electromagnetic shielding fabrics (electromagnetic shielding fabrics obtained by applying metal plating after fabric formation). Furthermore, they possessed moderate stretchability, reduced gloss and glare, and excellent wrinkle resistance. Additionally, the conductive fabrics obtained in Examples 1-3 showed minimal change in resistivity after storage in high-temperature and high-humidity environments, indicating high durability of electromagnetic shielding properties in such conditions.

[0062] Furthermore, Figure 5 shows a photograph of the conductive fabric obtained in Example 1 after being subjected to 100 kneading cycles according to "8.19.2 Method B (Scott method)" of JIS L 1096:2010 (Testing methods for woven and knitted fabrics). From Figure 5, it can be seen that although the conductive fabric of Example 1 had slight wrinkles, there was no significant change in its appearance, indicating that it is resistant to wrinkles.

[0063] On the other hand, the conductive fabric obtained in Comparative Example 1 had excellent electromagnetic shielding properties, but because the entire surface of the fabric was silver-plated, it had a high gloss and was very glaring. Furthermore, the conductive fabric obtained in Comparative Example 1 had a flat surface, making it prone to wrinkling, and its resistivity changed significantly after storage in a high-temperature, high-humidity environment, making it susceptible to (and prone to) the effects of electromagnetic shielding in such an environment. Figure 6 shows a photograph of the conductive fabric obtained in Comparative Example 1 after being subjected to 100 kneading cycles, similar to Example 1. From Figure 6, it can be seen that the conductive fabric of Comparative Example 1 had a significantly changed appearance with many wrinkles remaining, indicating that it is prone to wrinkling. The conductive fabrics obtained in Comparative Examples 2 and 3 had poor electromagnetic shielding properties due to their low CF and basis weight. [Explanation of Symbols]

[0064] The point where the warp threads, which are held in a 1:2 ratio, and the weft threads, which are also held in a 2:1 ratio, intersect.

Claims

1. A conductive fabric in which threads with a metallized surface are used as warp and weft threads, The conductive fabric has a transverse tear strength of 14N or more, a cover factor of 1485 to 2310, and a basis weight of 35 to 70 g / m². 2 A conductive fabric having an electric field shielding performance of 43 dB or more at 1 GHz.

2. The conductive fabric according to claim 1, wherein the metallized surface of the yarn is a synthetic fiber whose surface is silver-plated or silver-coated.

3. The conductive fabric according to claim 1, wherein the conductive fabric has an elongation rate of 30% or more in at least one of the warp and weft directions.

4. The conductive fabric is a ripstop fabric having a base fabric, warp ribs, and weft ribs. The conductive fabric according to any one of claims 1 to 3, wherein the warp ribs and weft ribs are formed by aligning 2 to 6 threads with a metallized surface.

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