Conductive fabric

Abstract

To provide an electroconductive fabric capable of maintaining excellent conductivity even with bending repeated.SOLUTION: An electroconductive fabric is obtained by laminating on a surface of a base material fabric a conductive sheet member obtained by burying a mesh-like base material in a conductive film made of a conductive composition. The mesh-like base material has an opening disposed so as to satisfy an opening ratio of 30% or more. For an arithmetic mean roughness Ra1 (unit: μm) of a first surface of the conductive sheet member and an arithmetic mean roughness Ra2 (unit: μm) of a second surface of the conductive sheet member, a relation of Ra1>Ra2 is satisfied, and the conductive sheet member is laminated so that the second surface thereof is on the side of the base material fabric.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a conductive fabric, and more particularly to a conductive fabric having excellent flex resistance. [Background technology]

[0002] As a flexible conductive member, a polymer film having a metal-containing coating formed on the surface thereof has been used. However, the conductive member having a polymer film having a metal-containing coating formed on the surface thereof has insufficient durability of conductivity against sharp bending or repeated bending.

[0003] For the purpose of improving durability against bending, for example, Patent Document 1 discloses a flexible circuit board for repeated bending applications, which has a polyimide insulating layer having a tensile modulus of elasticity of 4 to 6 GPa at 25°C and a thickness of 14 to 17 μm, a wiring circuit having a thickness of 7 to 13 μm, the ratio (tc / tp) of the thickness of the wiring circuit (tc) to the thickness of the polyimide insulating layer (tp) being in the range of 0.4 to 0.95, and a circuit protection layer having a thickness of 15 to 30 μm being further provided on the wiring circuit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2012 / 020677 Summary of the Invention [Problem to be solved by the invention]

[0005] However, even the flexible circuit board according to Patent Document 1 does not provide sufficient improvement in bending resistance. [Means for solving the problem]

[0006] The present inventors have carried out various studies on a conductive fabric in which a conductive sheet member having a mesh-shaped substrate embedded inside a conductive film made of a conductive composition is laminated on the surface of a substrate fabric. As a result, they have found that when the arithmetic mean roughness of the front surface and the back surface of the conductive sheet member are different and the surface with the relatively small arithmetic mean roughness is laminated on the substrate fabric side, the conductive fabric exhibits very excellent bending resistance, and have completed the present invention.

[0007] That is, the present invention provides a conductive fabric in which a conductive sheet member having a mesh-shaped substrate embedded inside a conductive film made of a conductive composition is laminated on the surface of a substrate fabric, The mesh-like substrate has openings so that the opening ratio is 30% or more. The arithmetic mean roughness Ra of the first surface of the conductive sheet member 1 (unit: μm) and the arithmetic average roughness Ra of the second surface of the conductive sheet member 2 (unit: μm) 1 >Ra 2 Fulfilling the relationship, The conductive fabric is characterized in that the second surface of the conductive sheet member is laminated on the base fabric side.

[0008] The arithmetic mean roughness Ra of the first surface of the conductive sheet member 1 (unit: μm) and the arithmetic average roughness Ra of the second surface of the conductive sheet member 2 (unit: μm) 2 / Ra 1 It is preferable that the value is within the range of 0.1 to 0.5.

[0009] The arithmetic mean roughness Ra of the second surface of the conductive sheet member 2 It is preferable that the thickness is within the range of 0.1 to 1.0 μm.

[0010] It is preferable that a portion of the mesh base material is exposed on the second surface of the conductive sheet member. Effect of the Invention

[0011] According to the present invention, it is possible to provide a conductive fabric in which the decrease in conductivity due to repeated bending deformation is suppressed. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic cross-sectional view showing an example of a conductive fabric of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The member constituting the conductive portion in the conductive fabric of the present invention is a conductive sheet member in which a mesh-like substrate is embedded inside a conductive film made of a conductive composition.

[0014] The conductive composition of the present invention preferably contains conductive particles and a polymer resin. Examples of the conductive particles include carbon particles, carbon nanotubes, and metal particles. Among them, metal particles are preferable when a high level of conductivity is required. Examples of the metal particles are preferably one type selected from the group consisting of silver particles, nickel particles, and copper particles, or a mixture of two or more types.

[0015] The primary particle size of the conductive particles is preferably 0.01 to 10.00 μm. When the primary particle size of the conductive particles is within the range of 0.01 to 10.00 μm, the effect of reducing resistance due to an increase in the contact ratio between conductive particles and preventing disconnection due to the ability to densely mix the conductive particles can be obtained. The particle shape of the conductive particles may be spherical, needle-shaped, scale-shaped, polyhedral, irregular, etc., and is not particularly limited.

[0016] The conductive particles are preferably mixed in an amount of 50 to 95% by mass relative to the mass of the conductive composition. If the conductive particles are mixed in an amount within this range, a conductive film having excellent conductivity can be formed.

[0017] The polymer resin to be blended in the conductive composition of the present invention is not particularly limited, and examples thereof include acrylic resin, phenoxy resin, polyvinyl formal resin, polystyrene resin, polyvinyl butyral resin, polyester resin, polyamide resin, polyimide resin, xylene resin, polyurethane resin, epoxy resin, etc. In addition, conductive polymer materials such as polypyrrole and PEDOT may be used.

[0018] The blending ratio of the polymer resin is preferably 5 to 50% by mass with respect to the mass of the conductive composition. If the blending ratio of the polymer resin is within this range, a smooth conductive film in which particles are more uniformly dispersed can be formed.

[0019] The conductive composition may contain, as appropriate, other components, such as a solvent, a viscosity modifier, a leveling agent, a wettability modifier, a preservative, and a stabilizer.

[0020] The mesh-like substrate in the present invention has a woven structure made of warp and weft. The warp and weft constituting the mesh-like substrate are preferably synthetic fibers such as nylon, polyester, acrylic, vinylon, polyethylene, and polypropylene. The warp or weft is preferably a filament yarn. It may be either a monofilament yarn or a multifilament yarn. The diameter of the warp or weft is preferably 20 to 70 μm. The diameters of the warp and weft may be the same or different, but in order to realize bending resistance independent of the bending direction, it is preferable that the warp and weft have the same diameter.

[0021] The weaving density of the warp and weft threads of the mesh-like substrate is adjusted so that the opening ratio is 30% or more. The weaving density can be appropriately set in consideration of the fineness of the warp and weft threads to weave a mesh-like substrate with an opening ratio of 30% or more. The opening ratio is more preferably 30 to 50%. The structure of the mesh-like substrate is not particularly limited to plain weave, twill weave, satin weave, etc. Plain weave is preferable in that bending resistance independent of bending direction can be obtained when a conductive fabric is formed. The opening ratio can be measured by analyzing an image of one surface of the mesh-like substrate and calculating the area ratio of the portion where no warp or weft thread exists per unit area.

[0022] The conductive sheet member of the present invention has a structure in which the mesh-shaped substrate is embedded inside a conductive film made of the conductive composition. The conductive composition is filled so as to penetrate the openings of the mesh-shaped substrate and cured to form a conductive film. At this time, the mesh-shaped substrate may be completely embedded inside the conductive film formed by curing the conductive composition, that is, in a covered state with no exposed portion. The mesh-shaped substrate may be partially exposed from one or both surfaces of the conductive sheet member.

[0023] The thickness of the mesh substrate is T B The thickness of the conductive film formed by curing the conductive composition is T M μm, T M / T B The value of T is preferably in the range of 1.1 to 1.5. M / T B If the value of T is within this range, it is possible to achieve both flexibility and surface conductivity of the conductive sheet member. M / T B The range is 1.1 to 1.2.

[0024] The conductive sheet member has a first surface and a second surface which are in a reverse relationship. Here, the arithmetic mean roughness Ra 1 (unit: μm) and the arithmetic average roughness Ra of the second surface 2(unit: μm) 1 >Ra 2 It is essential that the conductive sheet member is formed so as to satisfy the relationship: 1 (unit: μm) and the arithmetic average roughness Ra of the second surface of the conductive sheet member 2 (unit: μm) 2 / Ra 1 It is preferable that the value is within the range of 0.1 to 0.5.

[0025] Here, the arithmetic mean roughness Ra can be measured using a surface roughness measuring instrument SV-3000 (manufactured by Mitutoyo Corp.) The measurement conditions are in accordance with JIS B 0601:1994.

[0026] The arithmetic mean roughness Ra of the second surface of the conductive sheet member 2 is preferably in the range of 0.1 to 1.0 μm. Furthermore, it is preferable that a part of the mesh-like substrate is exposed on the second surface of the conductive sheet member. This allows the obtained conductive fabric to have a low resistance increase rate (%) in a repeated bending test. In other words, a conductive fabric having excellent conductivity with excellent bending resistance can be obtained.

[0027] As a method for producing the conductive sheet member of the present invention, a method can be adopted in which a releasable substrate having an arithmetic mean roughness smaller than that of the mesh substrate is first arranged, and the mesh substrate is placed on the releasable substrate, and the conductive composition having fluidity is applied from above the mesh substrate. Various printing methods including screen printing can be used as the application method. If a knife coating method is adopted as the application method, the arithmetic mean roughness of the conductive sheet member on the side where the knife contacts can be roughly equivalent to the arithmetic mean roughness of the mesh substrate. As a result, the arithmetic mean roughness of the side where the knife contacts can be formed larger than the arithmetic mean roughness of the side of the conductive sheet member on which the releasable substrate is arranged, that is, the side opposite to the side where the knife contacts. In other words, the side on which the releasable substrate is arranged becomes the second surface of the conductive sheet member, and the side on which the knife contacts becomes the first surface of the conductive sheet member. Here, the thickness T of the mesh substrate described above B and the thickness T of the conductive film formed by curing the conductive composition. M T M / T B If the value is in the range of 1.1 to 1.5, the effect of easily controlling the arithmetic mean roughness of the first surface by the knife coating method can be obtained.

[0028] As another method, a method can be adopted in which the conductive composition is applied to a first releasable substrate, and then the mesh-like substrate and the second releasable substrate are placed in this order before being cured to form a film, and the mesh-like substrate is embedded inside the conductive film made of the conductive composition by applying pressure from above. At this time, the arithmetic mean roughness of the first and second releasable substrates is copied to form the surface of the conductive film. Therefore, by appropriately selecting the arithmetic mean roughness of the first and second releasable substrates, the desired arithmetic mean roughness can be imparted to the first and second surfaces of the obtained conductive sheet member. That is, the arithmetic mean roughness of the second releasable substrate arranged on the side that becomes the second surface of the conductive sheet member is made smaller than the arithmetic mean roughness of the first releasable substrate arranged on the side that becomes the first surface of the conductive sheet member. In the conductive sheet member obtained by this method, the arithmetic mean roughness Ra of the first surface is 100 mm. 1The arithmetic mean roughness Ra of the second surface is 2 can be made smaller.

[0029] The conductive fabric of the present invention has a structure in which the conductive sheet member is laminated on at least one surface of the base fabric. The conductive sheet member may be laminated on the entire surface of the base fabric. Alternatively, the conductive sheet member may be cut to form a circuit or electrode of a desired shape, which may be laminated on a part of the base fabric. At this time, it is essential that the second surface of the conductive sheet member is laminated on the base fabric side. That is, of the front and back surfaces of the conductive sheet member, the surface having the smaller arithmetic mean roughness is laminated on the base fabric side. This makes it possible for the obtained conductive fabric to maintain a high level of conductivity even when repeatedly bent.

[0030] The conductive sheet member can be laminated and fixed on the surface of the base fabric by using a known means. Various adhesives may be used, or a method may be used in which a so-called hot-melt type polymer resin is used in the conductive composition constituting the conductive sheet member. The hot-melt type polymer resin is not particularly limited, but examples thereof include polyurethane resin, acrylic resin, polyester resin, polyamide resin, olefin resin, and EVA resin.

[0031] The conductive sheet member can be laminated on the surface of the base fabric by heat pressing or the like. For example, a hot melt resin can be laminated between the second surface side of the conductive sheet member and the base fabric, and then the hot melt resin can be bonded by heat pressing. As the hot melt resin, a sheet-like hot melt resin may be used, or a liquid hot melt resin may be applied to the second surface of the conductive sheet member. As the heat press machine, for example, a transfer press machine (manufactured by Hashima Co., Ltd.: model number HP-4536A-12) can be used. The conditions of the heat press treatment are a press temperature of 100 to 160°C and a press pressure of 50 to 500 g / cm. 2 It is preferable that the range is 100%.

[0032] Alternatively, a sheet-shaped hot melt resin may be laminated on one side of the mesh substrate in advance, and the conductive composition may be applied from the other side of the mesh substrate to form a conductive sheet member with an adhesive layer made of hot melt resin. At this time, it is required that the arithmetic mean roughness of the surface of the sheet-shaped hot melt resin laminated on one side of the mesh substrate is smaller than the arithmetic surface roughness of the mesh substrate. This allows the arithmetic surface roughness of the second surface side of the conductive sheet member to be smaller than the arithmetic mean roughness of the first surface side of the conductive sheet member.

[0033] Examples of the base fabric on which the conductive sheet member is laminated include fiber base fabrics such as woven fabrics, knitted fabrics, and nonwoven fabrics. Examples of the fiber material include natural fibers such as cotton, hemp, wool, and silk, regenerated fibers such as rayon and cupra, semi-synthetic fibers such as acetate and triacetate, and synthetic fibers such as polyamide (nylon 6, nylon 66, etc.), polyester (polyethylene terephthalate, polytrimethylene terephthalate, etc.), polyurethane, and polyacrylic, and two or more of these may be combined. Among them, a base fabric made of a synthetic fiber having excellent strength and chemical resistance is preferable, and a base fabric made of a synthetic fiber such as polyester fiber or nylon fiber is more preferable. The thread may be a monofilament thread or a multifilament thread formed by bundling a plurality of fibers. The fineness of the thread is not particularly limited, but is preferably 10 to 170 dtex. The base fabric may be dyed, antistatically treated, flame-retardant, calendared, etc., as necessary. The thickness of the base fabric is not particularly limited, but is preferably 0.02 to 1.00 mm. If the thickness of the base fabric is within the range of 0.02 to 1.00 mm, appropriate texture and flexibility can be maintained even after laminating the conductive sheet. EXAMPLES

[0034] Example 1 Polyester mesh fabric using monofilament (wire diameter 40 μm) for both warp and weft as mesh-like substrate: T230-40 (manufactured by Yamani Co., Ltd.: arithmetic mean roughness 0.67 μm, thickness T B = 60μm) was prepared. The opening ratio of this polyester mesh fabric was 40%. A release substrate with an arithmetic mean roughness of the surface of 0.26μm was attached to one side of this mesh substrate, and CI-1036 (manufactured by Engineered Materials Systems) containing silver particles (blending ratio 50 to 60 mass%) as a conductive composition ink was applied to the other side of the mesh substrate by screen printing. The screen printer used was SSA-PC560A (manufactured by Celia Engineering Co., Ltd.). The printing conditions are shown in Table 1.

[0035] [Table 1]

[0036] After printing, the conductive film (thickness T M = 66 μm) was formed to obtain a conductive sheet member. The surface to which the release substrate was attached was used as the second surface, and the Ra 2 / Ra 1 The value was 0.22. The mesh-like substrate was not exposed on the first surface of the obtained conductive sheet member, and the area ratio of the mesh-like substrate exposed on the second surface was 16.3%. A hot melt sheet UH203 (manufactured by Nihon Matai Co., Ltd.) was attached to the second surface of the conductive sheet member, and cut to a width of 1 mm and a length of 120 mm. In addition, a polyester plain weave fabric TE5880 (warp thread 30 dtex / 36 f; 192 threads / inch, weft thread 62 dtex / 150 f; 122 threads / inch) as the base fabric was cut to a width of 10 mm and a length of 120 mm. The cut conductive sheet member was laminated and bonded to the center of the width direction of the base fabric to obtain a conductive fabric.

[0037] Example 2 The mesh substrate is T300-35 (Yamani Co., Ltd.: arithmetic mean roughness 0.38 μm, thickness T B A conductive fabric was obtained in the same manner as in Example 1, except that a releasable substrate (fiber-reinforced plastic = 54 μm) was used. The surface to which the release substrate was attached was used as the second surface, and the Ra of the obtained conductive sheet member was 2 / Ra 1 The value was 0.35. The mesh-like substrate was not exposed on the first surface of the obtained conductive sheet member, and the area ratio of the mesh-like substrate exposed on the second surface was 18.2%.

[0038] Comparative Example 1 A conductive fabric was obtained in the same manner as in Example 1, except that the first surface side of the conductive sheet member was laminated onto the base fabric.

[0039] Comparative Example 2 A conductive fabric was obtained in the same manner as in Example 2, except that the first surface side of the conductive sheet member was laminated onto the base fabric.

[0040] A bending test was performed on the conductive fabrics obtained in the above examples and comparative examples using a DLD111L tabletop durability tester (manufactured by Yuasa System Co., Ltd.), and the resistance values ​​before and after the bending test were measured using an RM3545-02 (manufactured by Hioki E.E. Corporation). The bending conditions were such that the conductive fabric was bent 180° so that the surface on which the conductive sheet member was laminated was on the inside, and bending was performed 20,000 times with a bending radius of 2 mm. The rate of increase in resistance after the bending test relative to the resistance before the bending test was calculated as the resistance increase rate (%), and is shown in Table 2. It can be said that the lower the resistance increase rate (%), the higher the bending durability of the conductivity.

[0041] [Table 2] [Explanation of symbols]

[0042] 1: Conductive fabric 2: Conductive sheet material 3: Conductive film (hardened conductive composition) 4: Mesh-like substrate 5: Glue 6: Base fabric S 1 :Front page S 2 :Second side T B : Thickness of mesh substrate T M : Thickness of conductive film

Claims

1. A conductive fabric is formed by laminating a conductive sheet member, which is formed by embedding a mesh-shaped substrate inside a conductive film made of a conductive composition, on a surface of a substrate fabric, The mesh-like substrate has openings so that the opening ratio is 30% or more, The arithmetic average roughness Ra of the first surface of the conductive sheet member １ (unit: μm) and the arithmetic mean roughness Ra of the second surface of the conductive sheet member ２ (unit: μm) Ra １ >Ra ２ Fulfilling the relationship, A conductive fabric characterized in that the second surface of the conductive sheet member is laminated on the base fabric side.

2. The arithmetic mean roughness Ra of the first surface of the conductive sheet member １ (unit: μm) and the arithmetic mean roughness Ra of the second surface of the conductive sheet member ２ (unit: μm) ２ / Ra １ The conductive fabric according to claim 1, wherein the value of is in the range of 0.1 to 0.

5.

3. The arithmetic mean roughness Ra of the second surface of the conductive sheet member ２ The conductive fabric according to claim 1 or 2, characterized in that the thickness is in the range of 0.1 to 1.0 μm.

4. The conductive fabric according to any one of claims 1 to 3, characterized in that a portion of the mesh-like substrate is exposed on the second surface of the conductive sheet member.

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