Conductive nonwoven fabric, method for pre-treating conductive nonwoven fabric, method for manufacturing conductive nonwoven fabric, method for manufacturing conductive nonwoven tape, and method for manufacturing wire harness.

Abstract

The present invention provides a conductive nonwoven fabric that can be easily installed on electric wires and effectively provides shielding, a method for pre-treating the conductive nonwoven fabric, a method for manufacturing the conductive nonwoven fabric, a method for manufacturing conductive nonwoven fabric tape, and a method for manufacturing a wire harness. [Solution] The conductive nonwoven fabric 21 comprises a nonwoven fabric 21a and a plated portion 21b made of a conductive metal that covers the fibers constituting the nonwoven fabric 21a, with the weight of the plated portion 21b being 30 g / m 2 More than 96g / m 2 The following applies:

Description

[Technical Field]

[0001] This disclosure relates to conductive nonwoven fabrics, a method for pre-treating conductive nonwoven fabrics, a method for manufacturing conductive nonwoven fabrics, a method for manufacturing conductive nonwoven fabric tapes, and a method for manufacturing wire harnesses. [Background technology]

[0002] Conventionally, a cable has been proposed in which a conductive nonwoven fabric, comprising a nonwoven fabric and a plated portion made of a conductive metal covering the fibers constituting the nonwoven fabric, is arranged on the outer circumference of an electric wire (see, for example, Patent Document 1). This cable exhibits an electromagnetic shielding effect through the plated portion of the conductive nonwoven fabric, while also being able to follow the bending of the electric wire because the nonwoven fabric has relatively good tensile and compressive properties due to the material properties. In particular, in this cable, the conductive nonwoven fabric has a value of 4.0 or less obtained by dividing the electrical resistance value of the surface layer by the electrical resistance value of the intermediate layer located in the middle of the thickness direction, and a predetermined amount or more of conductive metal is ensured in the intermediate layer as well, so that it can exhibit an appropriate shielding effect. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2023 / 074771 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, if the conductive nonwoven fabric described in Patent Document 1 is plated with a large amount of conductive metal, it becomes too hard, making it difficult to wrap around electric wires, or causing it to unravel even if wrapped. On the other hand, if the amount of plated material is too small, the amount of conductive metal is insufficient, and the shielding effect cannot be properly achieved.

[0005] This disclosure is made to solve the aforementioned conventional problems, and its purpose is to provide a conductive nonwoven fabric that can be easily installed on electric wires and can appropriately exhibit a shielding effect, a method for pre-treating a conductive nonwoven fabric, a method for manufacturing a conductive nonwoven fabric, a method for manufacturing a conductive nonwoven fabric tape, and a method for manufacturing a wire harness. [Means for solving the problem]

[0006] The conductive nonwoven fabric according to this disclosure comprises a nonwoven fabric and a plated portion made of a conductive metal that covers the fibers constituting the nonwoven fabric, wherein the weight of the plated portion is 30 g / m². 2 More than 96g / m 2 The following applies:

[0007] The pretreatment method for conductive nonwoven fabrics according to this disclosure is for fabrics with a thickness of 0.30 mm or more and 1.00 mm or less, and a weight of 0.2 g / cm³ per unit volume. 3 More than 0.4g / cm 3 The method comprises: a first step of preparing the following nonwoven fabric; a second step of introducing the nonwoven fabric prepared in the first step into a treatment tank that has already been introduced with an organometallic complex soluble in supercritical carbon dioxide; a third step of supplying supercritical carbon dioxide to the treatment tank into which the nonwoven fabric was introduced in the second step, thereby creating an environment in the treatment tank with a pressure of 12 MPa to 15 MPa and a temperature of 100°C to 130°C; and a fourth step of removing the nonwoven fabric from the treatment tank after a period of 10 to 60 minutes has elapsed since the supercritical carbon dioxide was supplied in the third step and the environment was created. [Effects of the Invention]

[0008] According to this disclosure, it is possible to install the device well on power lines and to properly provide a shielding effect. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view showing a wire harness according to an embodiment of the present disclosure. [Figure 2] It is a cross-sectional view showing the details of the conductive nonwoven fabric tape shown in FIG. 1, wherein (a) shows a cross section orthogonal to the longitudinal direction of the tape, and (b) shows a partially enlarged view of (a). [Figure 3] It is a schematic diagram for explaining the pretreatment method for plating according to the present embodiment. [Figure 4] It is a table showing examples and comparative examples. [Figure 5] It is a configuration diagram showing an example of the conductive nonwoven fabric after half-wrap winding. [Figure 6] It is a graph showing the shielding performance of conductive nonwoven fabrics according to examples and comparative examples. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the present disclosure will be described with reference to preferred embodiments. It should be noted that the present disclosure is not limited to the embodiments shown below, and can be appropriately modified without departing from the spirit of the present disclosure. In addition, in the embodiments shown below, illustration and description of a part of the configuration are omitted in some places, and it goes without saying that publicly known or well-known techniques are appropriately applied to the details of the omitted techniques within a range that does not conflict with the content described below.

[0011] FIG. 1 is a perspective view showing a wire harness according to an embodiment of the present disclosure. As shown in FIG. 1, the wire harness 1 according to the present embodiment includes an electric wire 10 and a conductive nonwoven fabric tape 20 spirally wound, for example, in half-wrap around the electric wire 10.

[0012] The electric wire 10 comprises a conductor 11 made of, for example, copper, aluminum, or an alloy thereof, and an insulating covering portion 12 that covers the conductor 11. The conductor 11 of the electric wire 10 according to this embodiment may be a stranded wire made by twisting together a plurality of conductive strands, or it may be a single solid wire. The covering portion 12 may be made of PVC (Polyvinyl Chloride), PP (Polypropylene), or PE (Polyethylene). However, the covering portion 12 is not limited to these, and silicone, polyurethane, nylon, etc. may also be used. Furthermore, although there is one electric wire 10 in the example shown in Figure 1, there may be multiple electric wires, not just one.

[0013] The wire harness 1 having such electric wires 10 may, for example, have connectors at the ends, although these are not shown in the figures, and may have resin tape wrapping applied to some parts, to the extent that it does not interfere with adhesive attachment as described later. Furthermore, the wire harness 1 may include other components besides connectors and resin tape.

[0014] Figure 2 is a cross-sectional view showing details of the conductive nonwoven tape 20 shown in Figure 1, where (a) shows a cross-section perpendicular to the longitudinal direction of the tape, and (b) shows a partially enlarged view of (a). As shown in Figure 2(a), the conductive nonwoven tape 20 comprises a conductive nonwoven fabric 21 and an adhesive layer 22 provided on one side (front or back) of the conductive nonwoven fabric 21.

[0015] As shown in Figure 2(b), the conductive nonwoven fabric 21 comprises a nonwoven fabric 21a and a plated portion 21b. The nonwoven fabric 21a is a sheet-like material in which fibers are intertwined without weaving. As shown in Figure 2(b), due to the manufacturing characteristics, the fibers of this nonwoven fabric 21a are formed as numerous layers in the thickness direction. The fibers constituting such a nonwoven fabric 21a are, for example, polyethylene terephthalate (PET), PP, nylon, acrylic, glass fiber, carbon fiber, aramid fiber, and polyarylate fiber.

[0016] The plated portion 21b is a conductive metal that covers each fiber constituting the nonwoven fabric 21a. The plated portion 21b is made of, for example, copper, nickel, tin, silver, and alloys of these metals. The plated portion 21b may be formed as a single layer on the fibers constituting the nonwoven fabric 21a, or may be formed in a plurality of layers. Therefore, the plated portion 21b may be formed in the form of copper (first layer) and tin (second layer) on the fibers constituting the nonwoven fabric 21a, for example.

[0017] The adhesive layer 22 is composed of a material or the like that exhibits adhesive force, and the material is not particularly limited. This adhesive layer 22 is provided on at least one surface of the conductive nonwoven fabric 21 shown in Fig. 2(a). In the present embodiment, the adhesive layer 22 is formed only on one end in the width direction (an example of a partial portion) of one surface, corresponding to the conductive nonwoven fabric tape 20 being half-wrap wound. The adhesive layer 22 is not limited to being formed only on one end of the conductive nonwoven fabric 21, and may be formed only in the central portion, or may be formed in a plurality of stripes along the longitudinal direction, and the form thereof is not limited.

[0018] Furthermore, in the conductive nonwoven fabric 21 of the conductive nonwoven fabric tape 20 used for the wire harness 1 according to the present embodiment, the weight of the plated portion 21b per unit sheet area is 30 g / m 2 or more. In addition, in the conductive nonwoven fabric 21, the weight of the plated portion 21b per unit sheet area is 96 g / m 2 or less.

[0019] Here, as a result of intensive studies by the present inventors, it has been found that when the weight of the plated portion 21b of the conductive nonwoven fabric 21 is less than 30 g / m 2 , sufficient shielding effect cannot be exhibited, and when the weight of the plated portion 21b exceeds 96 g / m 2 , the structure becomes hard and it is difficult to wind around the electric wire 10.

[0020] That is, when the weight of the plated portion 21b is 30 g / m 2If the weight is less than 96g / m², it means that the weight of the plated portion 21b of the conductive nonwoven fabric 21 is insufficient, and it becomes impossible to secure enough metal to block noise. On the other hand, if the weight of the plated portion 21b is 96g / m² 2 If the value exceeds this, there is an excess of metal used in the plated portion 21b of the conductive nonwoven fabric 21, and the conductive nonwoven fabric 21 becomes hard due to the excess metal.

[0021] Therefore, in this embodiment, the conductive nonwoven fabric 21 has a plated portion 21b weight of 30 g / m². 2 More than 96g / m 2 The following applies. In order to achieve the weight of the plated portion 21b, the fiber density (weight per unit volume) and thickness of the nonwoven fabric 21a before plating the conductive nonwoven fabric 21 must be appropriate.

[0022] Next, a pretreatment method for the conductive nonwoven fabric 21 according to this embodiment, as well as a method for manufacturing the conductive nonwoven fabric 21, the conductive nonwoven tape 20, and the wire harness 1, will be described. Figure 3 is a schematic diagram illustrating the pretreatment method for plating according to this embodiment.

[0023] To manufacture a conductive nonwoven fabric 21 with an appropriate weight for the plated portion 21b as described above, the thickness must be between 0.30 mm and 1.00 mm, and the weight per unit volume must be 0.2 g / cm³. 3 More than 0.4g / cm 3 The following nonwoven fabric 21a is prepared (Step 1).

[0024] Next, the nonwoven fabric 21a is introduced into the housing (processing tank) 40, which already contains the organometallic complex 30 shown in Figure 3 (second step). At this time, the nonwoven fabric 21a is stored in a state where it is wound, for example, twice around a cylindrical bobbin provided inside the housing 40. The organometallic complex 30 introduced is one that is soluble in supercritical carbon dioxide, such as palladium or nickel.

[0025] After storage, supercritical carbon dioxide is supplied to the enclosure 40 (third step). The environment inside the enclosure 40 is maintained at a pressure of 12 MPa to 15 MPa and a temperature of 100°C to 130°C by the supply of supercritical carbon dioxide. The circulation flow rate of supercritical carbon dioxide during processing is 0.5 kg / min to 8 kg / min.

[0026] Through this process, the organometallic complex 30 is dissolved in the oil of the fibers constituting the nonwoven fabric 21a via supercritical carbon dioxide and then reduced, causing the organometallic complex 30 to decompose and precipitate on the fiber surface of the nonwoven fabric 21a.

[0027] Next, after a predetermined time has elapsed since the inside of the housing 40 was set to the above environment (for example, after 10 minutes to 60 minutes), the nonwoven fabric 21a is removed from the housing 40 (fourth step). This completes the pretreatment of the conductive nonwoven fabric 21.

[0028] Next, the oil is removed. This is done by heating the fibers at, for example, 150°C or higher (or 250°C or higher depending on the heat resistance of the fibers) for 60 minutes or more. This process removes the oil from the fibers and activates the metals that have precipitated on them.

[0029] Next, electroless plating is performed on the nonwoven fabric 21a, from which the oil has been removed and the metal has been activated (5th step). The plating metal is, for example, copper. This makes it possible to manufacture a conductive nonwoven fabric 21 in which the weight of the plated portion 21b is appropriately sized as described above.

[0030] Subsequently, as shown in Figure 2, an adhesive layer 22 is formed on one surface of the conductive nonwoven fabric 21 (sixth step). This completes the production of the conductive nonwoven tape 20. The adhesive layer 22 may be formed, for example, by applying double-sided tape, or by providing a chemical layer such as an adhesive.

[0031] Next, the conductive nonwoven tape 20 is wrapped around the electric wire 10 (step 7). This produces the wire harness 1 shown in Figure 1.

[0032] Next, examples and comparative examples will be described. Figure 4 is a diagram showing examples and comparative examples. The conductive nonwoven fabrics shown in Examples 1 to 3 and Comparative Examples 1 to 3 in Figure 4 were produced by the manufacturing method described above (a manufacturing method with unified conditions), and the material of the nonwoven fabric is PET in all cases, and the plating metal is copper in all cases.

[0033] The initial specifications for the nonwoven fabric in Comparative Example 1 were a thickness of 0.20 mm and a basis weight of 65 g / m². 2 , and density (weight per unit volume) 0.3 g / cm³ 3 Furthermore, the initial specifications for Comparative Example 2 were a thickness of 0.25 mm and a basis weight of 85 g / m². 2 , and density 0.3 g / cm³ 3 The initial specifications for Example 1 were a thickness of 0.30 mm and a basis weight of 130 g / m². 2 , and density 0.4 g / cm³ 3 The initial specifications for Example 2 are a thickness of 0.55 mm and a basis weight of 180 g / m². 2 , and density 0.3 g / cm³ 3 The initial specifications for Comparative Example 3 were a thickness of 1.00 mm and a basis weight of 100 g / m². 2 , and density 0.1 g / cm³ 3 The initial specifications for Example 3 are a thickness of 1.00 mm and a basis weight of 200 g / m². 2 , and density 0.2 g / cm³ 3 That is the case.

[0034] When copper plating was applied to this initial nonwoven fabric, the plating weight was 20 g / m² in Comparative Example 1. 2 Therefore, in Comparative Example 2, the result was 23 g / m². 2 Therefore, in Example 1, the concentration was 30 g / m². 2 The result was 67 g / m². Furthermore, the plating weight in Example 2 was 67 g / m². 2 Therefore, in Comparative Example 3, the result was 27 g / m². 2 Therefore, in Example 3, the value was 96 g / m². 2 That's what happened.

[0035] These examples and comparative examples were evaluated from three perspectives: plating performance, shielding performance, and ease of use of the tape. The plating performance was evaluated to see if the thickness of the nonwoven fabric, which was initially specified in the pretreatment and subjected to pressure using supercritical carbon dioxide, had become too thin compared to its initial thickness. Each example and comparative example was evaluated as "○" if it maintained a thickness of 50% or more of its initial thickness, and as "×" if it became less than 50% of its initial thickness. This is because if the thickness becomes too thin, it becomes hard and difficult to wind.

[0036] Shielding performance was evaluated based on whether the conductive nonwoven fabric provided a shielding effect of 30 dB or more, which is generally considered to be effective, in the frequency band between 100 kHz and 1 GHz. Each example and comparative example was evaluated as "○" if it provided a shielding effect of 30 dB or more across the entire frequency band between 100 kHz and 1 GHz, and as "×" if it provided a shielding effect of less than 30 dB in any part of the frequency band between 100 kHz and 1 GHz.

[0037] The ease of use of the tape was evaluated based on how smoothly it could be wrapped around the wire with minimal unevenness. The ease of use of the tape was evaluated by forming an adhesive layer on a conductive nonwoven fabric and then wrapping it in a half-wrap fashion. The adhesive layer was a 50 μm thick double-sided tape, formed on only one side and one end to accommodate the half-wrap fashion. Figure 5 is a diagram showing an example of the conductive nonwoven fabric after half-wrap wrapping. As shown in Figure 5, each example and comparative example was evaluated as "○" if the gap, which is the difference in radial unevenness of the wire, was less than 2 mm, and as "×" if the gap was 2 mm or more. When the gap is large, it indicates that the conductive nonwoven fabric is too hard and cannot be wrapped properly.

[0038] First, the conductive nonwoven fabric and conductive nonwoven tape according to Comparative Example 1 received a "○" in the evaluation of plating treatment and ease of use of the tape, but received a "×" in shielding performance. Figure 6 is a graph showing the shielding performance of the conductive nonwoven fabric according to the example and comparative example. Note that Comparative Example 3 is not shown in Figure 6. As shown in Figure 6, the conductive nonwoven fabric according to Comparative Example 1 was only able to exhibit a shielding effect of 30 dB or more at 15 MHz to 80 MHz and 150 MHz and above.

[0039] Furthermore, the conductive nonwoven fabric and conductive nonwoven tape of Comparative Example 2 also received a "○" in the evaluation of plating treatment and ease of use of the tape, but received a "×" in shielding performance. As shown in Figure 6, the conductive nonwoven fabric of Comparative Example 2 could only exhibit a shielding effect of 30 dB or more at 10 MH or higher.

[0040] The conductive nonwoven fabric and conductive nonwoven tape in Comparative Example 3 received a "×" in the evaluation of the plating treatment. In particular, the conductive nonwoven fabric in Comparative Example 3 was compressed to about 1 / 3 of its thickness by the pretreatment, causing the single threads to stick together and becoming extremely hard. As a result, it was difficult to wrap the conductive nonwoven fabric in close contact with the wire, and when it was wrapped forcibly, many folds, plating cracks, and lifting of the nonwoven fabric from the wire occurred, making it difficult to measure the shielding effect. Therefore, the ease of use of the tape was evaluated as "×", and the shielding performance was evaluated as "-" as it could not be measured.

[0041] In contrast, the conductive nonwoven fabric and conductive nonwoven tape in Example 1 received a "○" rating in all aspects, including plating, shielding performance, and ease of use of the tape. In particular, as shown in Figure 6, the shielding performance demonstrated a shielding effect of 30 dB or more from 50 kHz and above. Similarly, Examples 2 and 3 also received a "○" rating in all aspects, demonstrating a shielding effect of 30 dB or more from 50 kHz and above.

[0042] As described above, Comparative Examples 1-3 all received a "×" in at least one evaluation, while Examples 1-3 all received a "〇". Therefore, it was found that the performance of conductive nonwoven fabrics and conductive nonwoven fabric tapes differs depending on the initial specifications of the nonwoven fabric. In particular, the thickness and density of the nonwoven fabric are easily affected by the plating weight when the plated area is formed. The initial specifications of the nonwoven fabric were a thickness of 0.30 mm to 1.00 mm and a density of 0.2 g / cm³. 3 More than 0.4g / cm 3 The following was found to be optimal.

[0043] Thus, according to the conductive nonwoven fabric 21 of this embodiment, the weight of the plated portion 21b is 30 g / m 2 More than 96g / m 2 The following is the result. As a result, the amount of conductive metal in the plated portion 21b is optimized, making it less likely that the amount of metal will be too high, resulting in excessive hardness, or that the amount of metal will be too low, resulting in insufficient shielding effect. Therefore, it is possible to provide a conductive nonwoven fabric 21 that can be easily installed on the electric wire 10 and that can properly exhibit a shielding effect.

[0044] Furthermore, according to the pretreatment method for the conductive nonwoven fabric 21 of this embodiment, the initial state is a thickness of 0.30 mm or more and 1.00 mm or less, and a density of 0.2 g / cm³. 3 More than 0.4g / cm 3 The following nonwoven fabric 21a is prepared, and a pre-treatment for plating is performed by dissolving an organometallic complex 30 using supercritical carbon dioxide. Therefore, a suitable conductive nonwoven fabric 21 can be obtained using the nonwoven fabric 21a that has undergone this pre-treatment. Accordingly, a pre-treatment method for a conductive nonwoven fabric 21 that can be easily installed on the electric wire 10 and that can properly exhibit a shielding effect can be provided.

[0045] Furthermore, according to the conductive nonwoven fabric 21, conductive nonwoven tape 20, or wire harness 1 of this embodiment, it is possible to provide a method for manufacturing the conductive nonwoven fabric 21, conductive nonwoven tape 20, or wire harness 1 that can be installed well on the electric wire 10 and can appropriately exhibit a shielding effect.

[0046] The present disclosure has been described above based on embodiments, but the present disclosure is not limited to the above embodiments, and modifications may be made without departing from the spirit of the present disclosure. In addition, although the examples use electroless plating, electroplating may be performed on top of the electroless plating, or known or well-known technologies may be combined if possible.

[0047] For example, in this embodiment, the wire harness 1 is composed of electric wires 10 and conductive nonwoven tape 20. However, it is not limited to this, and the wire harness 1 may further include other elements such as an outer covering member such as a corrugated tube or other electric wires outside the conductive nonwoven tape 20.

[0048] In addition, the conductive nonwoven tape 20 is wrapped around the electric wire 10 in a half-wrap fashion, but it is not limited to a half-wrap fashion. [Explanation of symbols]

[0049] 1: Wire harness 10: Electric wire 20: Conductive nonwoven fabric tape 21: Conductive nonwoven fabric 21a: Non-woven fabric 21b: Plating part 22:Adhesive layer 30: Organometallic complex 40: Enclosure (processing tank)

Claims

1. A conductive nonwoven fabric comprising a nonwoven fabric and a plated portion made of a conductive metal that covers the fibers constituting the nonwoven fabric, The weight of the plated portion is 30 g / m ２ 96g / m or more ２ The following is A conductive nonwoven fabric characterized by the following features.

2. Thickness of 0.30 mm or more and 1.00 mm or less, and weight per unit volume of 0.2 g / cm³ ３ 0.4g / cm or more ３ The first step involves preparing the following nonwoven fabric, The second step involves introducing the nonwoven fabric prepared in the first step into a treatment tank that has already been treated with an organometallic complex soluble in supercritical carbon dioxide, In the third step, supercritical carbon dioxide is supplied to the processing tank into which the nonwoven fabric was introduced in the second step, thereby creating an environment in the processing tank with a pressure of 12 MPa to 15 MPa and a temperature of 100°C to 130°C. In the third step, carbon dioxide is supplied in a supercritical state to create the environment, and after a period of 10 to 60 minutes has elapsed, the nonwoven fabric is removed from the processing tank in the fourth step. A method for pre-treating conductive nonwoven fabrics, characterized by comprising the following:

3. The method for pre-treating a conductive nonwoven fabric according to claim 2 comprises a fifth step in which the nonwoven fabric removed in the fourth step is subjected to a metal plating process by electroless plating to form a conductive nonwoven fabric. A method for producing a conductive nonwoven fabric, characterized by the following:

4. The method for manufacturing a conductive nonwoven fabric according to claim 3 comprises a sixth step of forming an adhesive layer on the conductive nonwoven fabric obtained in the fifth step. A method for producing a conductive nonwoven tape characterized by the following:

5. The method for manufacturing a conductive nonwoven tape according to claim 4 further comprises a sixth step of winding the conductive nonwoven tape obtained by forming the adhesive layer onto an electric wire. A method for manufacturing a wire harness, characterized by the following features.

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