Conductive nonwoven fabric, method for pretreating conductive nonwoven fabric, method for manufacturing conductive nonwoven fabric, method for manufacturing conductive nonwoven fabric tape, and method for manufacturing wire harness

Abstract

The conductive nonwoven fabric includes a nonwoven fabric and a plated portion made of a conductive metal and covered by the fiber constituting the nonwoven fabric. The plated portion has a weight per unit area of 30 g / m 2 The above and 96 g / m 2 The following.

Description

Technical Field

[0001] This invention relates to a conductive nonwoven fabric, a pretreatment method for conductive nonwoven fabric, a manufacturing method for conductive nonwoven fabric, a manufacturing method for conductive nonwoven fabric tape, and a manufacturing method for wire harness. Background Technology

[0002] In the prior art, a cable has been proposed in which a conductive nonwoven fabric is provided on the outer periphery of the wire. This conductive nonwoven fabric includes a nonwoven fabric and a plated portion made of conductive metal and covered by fibers constituting the nonwoven fabric (see, for example, Patent Document 1). In this cable, the plated portion of the conductive nonwoven fabric exhibits electromagnetic shielding while, due to the material properties, the nonwoven fabric is relatively excellent in terms of stretching and compression, and can follow the bending of the wire. Specifically, in the conductive nonwoven fabric of the cable, the value obtained by dividing the surface resistance value by the resistance value of the intermediate layer at the midpoint in the thickness direction is set to 4.0 or less, ensuring a predetermined amount of conductive metal in the intermediate layer and appropriately exhibiting a shielding effect.

[0003] Reference List

[0004] Patent documents

[0005] Patent Document 1: WO2023 / 074771 Summary of the Invention

[0006] However, the conductive nonwoven fabric described in Patent Document 1 becomes too stiff when coated with a large amount of conductive metal, leading to problems such as difficulty in wrapping the conductive nonwoven fabric around the wire and the nonwoven fabric unraveling even when wrapped around the wire. On the other hand, when the amount of coated portion is too small, the amount of conductive metal is also small, thus failing to provide adequate shielding.

[0007] This disclosure is made to solve such problems in the prior art, and the purpose of this disclosure is to provide a conductive nonwoven fabric that can be well placed on a wire and can appropriately exhibit a shielding effect, a pretreatment method for a conductive nonwoven fabric, a method for manufacturing a conductive nonwoven fabric tape, and a method for manufacturing a wire harness.

[0008] The conductive nonwoven fabric includes a nonwoven fabric and a plated portion made of conductive metal and covered by fibers constituting the nonwoven fabric. The weight of the plated portion is 30 g / m². 2 Above and 96 g / m 2 the following.

[0009] A pretreatment method for conductive nonwoven fabric, the pretreatment method comprising: a first step of preparing a nonwoven fabric 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 Above and 0.4 g / cm3 The following steps are involved: First, the nonwoven fabric prepared in the first step is loaded into a treatment tank containing an organometallic complex that is soluble in carbon dioxide under supercritical conditions; second, supercritical carbon dioxide is supplied to the treatment tank containing the nonwoven fabric in the second step, and the interior of the treatment tank is set to an environment with a pressure of 12 MPa or higher and 15 MPa or lower, and a temperature of 100°C or higher and 130°C or lower; and fourth, after supplying the supercritical carbon dioxide and setting the environment in the third step, the nonwoven fabric is removed from the treatment tank after a time of 10 minutes or more and 60 minutes or less.

[0010] According to this disclosure, conductive nonwoven fabric can be properly placed on the wire and a shielding effect can be appropriately achieved. Attached Figure Description

[0011] Figure 1 This is a perspective view showing a wire harness according to an embodiment of the present disclosure;

[0012] Figure 2 Parts (a) and (b) are shown Figure 1 The cross-sectional view showing details of the conductive nonwoven fabric tape is shown, in which... Figure 2 Part (a) shows a cross-section orthogonal to the length direction of the belt, and Figure 2 Part (b) shows Figure 2 A magnified view of part (a);

[0013] Figure 3 This is a schematic diagram illustrating the plating pretreatment method according to this embodiment;

[0014] Figure 4 These are diagrams illustrating the embodiments and comparative examples;

[0015] Figure 5 This is a structural diagram showing an example of a conductive nonwoven fabric after partial wrapping; and

[0016] Figure 6 This is a graph showing the shielding performance of the conductive nonwoven fabrics according to the embodiments and comparative examples. Detailed Implementation

[0017] The present disclosure will now be described with reference to preferred embodiments. The present disclosure is not limited to the following embodiments and may be modified as appropriate without departing from the spirit of the present disclosure. In the embodiments described below, portions of the construction may be omitted from the illustrations and descriptions, and it is understood that known or publicly available techniques are appropriately applied to the omitted details without contradicting the description below.

[0018] Figure 1 This is a perspective view illustrating a wire harness according to an embodiment of the present disclosure. Figure 1 As shown, the wire harness 1 according to this embodiment includes an electric wire 10 and a conductive nonwoven fabric tape 20 that is wound in a spiral shape around the electric wire 10 in a semi-wrapped manner.

[0019] The wire 10 includes a conductor 11 made of, for example, copper, aluminum, or an alloy thereof, and an insulating sheath 12 covering the conductor 11. According to this embodiment, the conductor 11 of the wire 10 may be a stranded wire formed by twisting together multiple conductive elements, or it may be a single wire. The sheath 12 is made of polyvinyl chloride (PVC), polypropylene (PP), polyethylene (PE), or the like. However, the sheath 12 is not limited to the above and may also be made of silicone resin, polyurethane, nylon, or the like. Figure 1 The number of wires 10 in the example is one, but the number is not limited to one and can be more than two.

[0020] Although not shown, a wire harness 1 including such wires 10 may, for example, include a connector at the end, and a portion of the wire harness 1 may be wrapped with resin tape to the extent that it does not impede the assembly achieved by adhesive as described later. Furthermore, the wire harness 1 may include other components, not limited to connectors and resin tape.

[0021] Figure 2 Parts (a) and (b) are shown Figure 1 The diagram shows a detailed cross-sectional view of the conductive nonwoven fabric tape 20, in which... Figure 2 Part (a) shows a cross-section orthogonal to the length direction of the belt, and Figure 2 Part (b) shows Figure 2 A magnified view of part (a). For example... Figure 2 As shown in part (a), the conductive nonwoven tape 20 includes a conductive nonwoven fabric 21 and an adhesive layer 22 disposed on the surface (front surface or back surface) of the conductive nonwoven fabric 21.

[0022] like Figure 2 As shown in section (b), the conductive nonwoven fabric 21 includes a nonwoven fabric 21a and a plated portion 21b. The nonwoven fabric 21a is a sheet-like component in which fibers are interwoven without being woven. Figure 2 As shown in part (b), the fibers of the nonwoven fabric 21a are multilayered in the thickness direction in terms of manufacturing characteristics. The fibers constituting the nonwoven fabric 21a are made of, for example, polyethylene terephthalate (PET), PP, nylon, acrylic, glass fiber, carbon fiber, aramid fiber, polyarylate fiber, etc.

[0023] The plating portion 21b is a conductive metal covering the fibers constituting the nonwoven fabric 21a. The plating portion 21b is made of, for example, copper, nickel, tin, silver, or an alloy of these metals. The plating portion 21b can be formed as a single layer on the fibers constituting the nonwoven fabric 21a, or it can be formed as multiple layers. Therefore, the plating portion 21b can be formed on the fibers constituting the nonwoven fabric 21a as, for example, copper (first layer) and tin (second layer).

[0024] The adhesive layer 22 is made of a material that exhibits adhesive strength, and there are no particular limitations on the material. The adhesive layer 22 is disposed on... Figure 2 At least one surface of the conductive nonwoven fabric 21 shown in part (a). In this embodiment, the adhesive layer 22 is formed only at one end (a partial example) of the width direction of one surface to correspond to the semi-wrap of the conductive nonwoven fabric strip 20. The adhesive layer 22 is not limited to being formed only at one end of the conductive nonwoven fabric 21, but may also be formed only at its central portion, or may be formed as multiple ribs along its length direction, and its form is not limited.

[0025] Furthermore, in the conductive nonwoven fabric 21 of the conductive nonwoven fabric tape 20 used in the wire harness 1 according to this embodiment, the weight per unit area of ​​the plated portion 21b is 30 g / m. 2 The above. In the conductive nonwoven fabric 21, the weight per unit area of ​​the plated portion 21b is 96 g / m. 2 the following.

[0026] Here, as a result of in-depth discussion by the inventors of this application, it has been found that when the weight per unit area of ​​the plated portion 21b is less than 30 g / m², 2 At that time, the conductive nonwoven fabric 21 cannot fully demonstrate the shielding effect, and when the weight per unit area of ​​the plated part 21b exceeds 96 g / m², the shielding effect is insufficient. 2 At this time, the conductive nonwoven fabric 21 will harden and become difficult to wrap around the wire 10.

[0027] That is, when the weight per unit area of ​​the plated part 21b is less than 30 g / m 2 At that time, the weight of the plated portion 21b of the conductive nonwoven fabric 21 is relatively small, and therefore it is impossible to ensure an amount of metal sufficient to block noise. On the other hand, when the weight per unit area of ​​the plated portion 21b exceeds 96 g / m²... 2 At that time, the metal used for the plated portion 21b of the conductive nonwoven fabric 21 is excessive, and the conductive nonwoven fabric 21 becomes hard due to the excessive metal.

[0028] Therefore, in the conductive nonwoven fabric 21 of this embodiment, the weight per unit area of ​​the plated portion 21b is 30 g / m². 2 Above and 96 g / m 2Below. In order to achieve such a weight per unit area of ​​the plated part 21b, it is necessary to optimize the fiber density (weight per unit volume) and thickness of the nonwoven fabric 21a before plated with the conductive nonwoven fabric 21.

[0029] Next, a pretreatment method for the conductive nonwoven fabric 21 according to this embodiment, as well as a manufacturing method for the conductive nonwoven fabric 21, the conductive nonwoven fabric tape 20, and the wire harness 1, will be described. Figure 3 This is a schematic diagram illustrating the plating pretreatment method according to this embodiment.

[0030] In order to manufacture a conductive nonwoven fabric 21 with optimized weight per unit area of ​​the plated portion 21b as described above, a thickness of 0.30 mm or more and 1.00 mm or less, and a weight per unit volume of 0.2 g / cm³ are prepared. 3 Above and 0.4 g / cm 3 The following is nonwoven fabric 21a (first step).

[0031] Next, the nonwoven fabric 21a is loaded into the housing (processing tank) 40 (second step), wherein the housing 40 contains... Figure 3 The organometallic complex 30 is shown. At this time, the nonwoven fabric 21a is stored with, for example, two turns wound around a cylindrical spool disposed in the housing 40. The organometallic complex 30 contains substances that are soluble in carbon dioxide under supercritical conditions, such as palladium and nickel.

[0032] After storage, supercritical carbon dioxide is supplied to the shell 40 (third step). Due to the supply of supercritical carbon dioxide, the interior of the shell 40 is set to an environment with a pressure of 12 MPa or higher and 15 MPa or lower, and a temperature of 100°C or higher and 130°C or lower. During processing, the circulation rate of supercritical carbon dioxide is 0.5 kg / min or higher and 8 kg / min or lower.

[0033] Through this process, the organometallic complex 30 is dissolved in the oiling agent constituting the fibers of the nonwoven fabric 21a via supercritical carbon dioxide and is subsequently reduced, and the organometallic complex 30 decomposes and deposits on the surface of the fibers constituting the nonwoven fabric 21a.

[0034] Next, after a predetermined time (for example, after a time of 10 to 60 minutes) after the interior of the housing 40 has been set to the aforementioned environment, the nonwoven fabric 21a is removed from the housing 40 (fourth step). Thus, the pretreatment of the conductive nonwoven fabric 21 is completed.

[0035] Subsequently, the oil is removed. This is done, for example, by heat treatment at 150°C or higher (or 250°C or higher depending on the fiber's heat resistance) for at least 60 minutes. Through this treatment, the oil on the fiber is removed, and the metal deposited on the fiber is activated.

[0036] Next, the nonwoven fabric 21a, after the oiling agent has been removed and the metal has been activated, undergoes an electroless plating process (fifth step). For example, copper is used as the plating metal. As a result, it is possible to manufacture a conductive nonwoven fabric 21 with optimized weight per unit area of ​​the plating portion 21b as described above.

[0037] After that, as Figure 2 As shown in parts (a) and (b), for example, an adhesive layer 22 is formed on one surface of the conductive nonwoven fabric 21 (sixth step). Thus, the conductive nonwoven tape 20 is manufactured. The adhesive layer 22 can be formed, for example, by attaching double-sided tape or by providing a chemical layer such as an adhesive.

[0038] Next, the conductive nonwoven fabric tape 20 is wrapped around the wire 10 (seventh step). This creates a device as shown in the image. Figure 1 The wire harness shown is 1.

[0039] Next, embodiments and comparative examples will be described. Figure 4 This is a diagram illustrating the embodiments and comparative examples. Manufactured using the above-described manufacturing method (a manufacturing method with uniform conditions). Figure 4 The conductive nonwoven fabrics shown in Examples 1 to 3 and Comparative Examples 1 to 3 are used, and for all nonwoven fabrics, the material is PET and the plated metal is copper.

[0040] Regarding Comparative Example 1, the initial specifications of the nonwoven fabric were a thickness of 0.20 mm and a weight of 65 g / m². 2 The base weight, and 0.3g / cm 3 The density (weight per unit volume). The initial specifications of Comparative Example 2 were a thickness of 0.25 mm and 85 g / m³. 2 The base weight and 0.3 g / cm 3 The density, and the initial specifications of Example 1 were a thickness of 0.30 mm and 130 g / m³. 2 The base weight and 0.4 g / cm 3 The density. The initial specifications for Example 2 were a thickness of 0.55 mm and a density of 180 g / m³. 2 The base weight and 0.3 g / cm 3 The density, and the initial specifications of Comparative Example 3 were a thickness of 1.00 mm and 100 g / m³. 2 The base weight and 0.1 g / cm 3 The density. The initial specifications for Example 3 were a thickness of 1.00 mm and a density of 200 g / m³.2 The base weight and 0.2 g / cm 3 The density.

[0041] As a result of copper plating on a nonwoven fabric with such initial specifications, the coating weight in Comparative Example 1 was 20 g / m². 2 The coating weight in Comparative Example 2 was 23 g / m². 2 Furthermore, the coating weight in Example 1 was 30 g / m². 2 Furthermore, the coating weight in Example 2 was 67 g / m². 2 The coating weight in Comparative Example 3 was 27 g / m². 2 Furthermore, the coating weight in Example 3 was 96 g / m². 2 .

[0042] These embodiments and comparative examples were evaluated from three perspectives: coating treatment, shielding performance, and ease of use of the tape. Regarding the coating treatment, it was evaluated whether the thickness of the nonwoven fabric obtained by applying pressure to the nonwoven fabric with initial specifications due to supercritical carbon dioxide during pretreatment was too thin relative to the initial thickness. Each embodiment and comparative example was evaluated as "excellent" when maintaining a thickness of 50% or more relative to the initial thickness, and as "inferior" when the obtained thickness was less than 50% relative to the initial thickness. This is because when the thickness is too thin, the nonwoven fabric becomes stiff and difficult to wind.

[0043] Regarding shielding performance, the conductive nonwoven fabric was evaluated for exhibiting a shielding effect of 30 dB or more, which is generally considered to be a shielding effect, in the frequency band above 100 kHz and below 1 GHz. When the shielding effect of 30 dB or more was exhibited throughout the entire frequency band above 100 kHz and below 1 GHz, the embodiments and comparative examples were evaluated as "excellent," and when the shielding effect of less than 30 dB was exhibited in the frequency band above 100 kHz and below 1 GHz, the embodiments and comparative examples were evaluated as "inferior."

[0044] Regarding the tape's usability, its ability to be wound around the wire with minimal unevenness was evaluated. The usability was assessed by forming an adhesive layer on a conductive nonwoven fabric and then performing a partial wrap. The adhesive layer was formed by attaching a 50 μm thick double-sided tape only to one end of the surface corresponding to the partial wrap. Figure 5 This is a structural diagram showing an example of a conductive nonwoven fabric after partial wrapping. (See diagram for example.) Figure 5 As shown, when the radial unevenness of the wire protrusion is less than 2 mm, each embodiment and comparative example is evaluated as "excellent," and when the protrusion is 2 mm or more, each embodiment and comparative example is evaluated as "inferior." Large protrusions indicate that the conductive nonwoven fabric is too stiff and cannot be properly wound.

[0045] First, the conductive nonwoven fabric and conductive nonwoven tape of Comparative Example 1 were rated as "excellent" in terms of plating treatment and ease of use of the tape, but were rated as "inferior" in terms of shielding performance. Figure 6 This is a graph showing the shielding performance of the conductive nonwoven fabrics according to the embodiments and comparative examples. Figure 6 Comparative Example 3 is not shown. (e.g.) Figure 6 As shown, the conductive nonwoven fabric according to Comparative Example 1 exhibits a shielding effect of more than 30 dB only in the frequency band of 15 MHz and above and 80 MHz and the frequency band of 150 MHz and above.

[0046] Furthermore, the conductive nonwoven fabric and conductive nonwoven tape of Comparative Example 2 were rated "excellent" in terms of plating treatment and ease of use, but "inferior" in terms of shielding performance. Figure 6 As shown, the conductive nonwoven fabric according to Comparative Example 2 exhibits a shielding effect of more than 30 dB only in the frequency band above 10 MHz.

[0047] The conductive nonwoven fabric and conductive nonwoven tape according to Comparative Example 3 were evaluated as "inferior" in terms of plating treatment. Specifically, the conductive nonwoven fabric according to Comparative Example 3 was compressed to approximately 1 / 3 of its aforementioned thickness through pretreatment, and the individual yarns were bonded together, making the conductive nonwoven fabric very stiff. Therefore, it was difficult to wind the conductive nonwoven fabric according to Comparative Example 3 into a tight contact with the wire, and when forcibly wound, numerous creases or plating cracks and protrusions appeared in the nonwoven fabric, making it difficult to measure the shielding effect. Therefore, the conductive nonwoven fabric and conductive nonwoven tape according to Comparative Example 3 were evaluated as "inferior" in terms of ease of use, and their shielding performance was evaluated as "-", indicating that measurement was not possible.

[0048] On the other hand, the conductive nonwoven fabric and conductive nonwoven tape according to Example 1 were evaluated as "excellent" in terms of plating treatment, shielding performance, and ease of use. In particular, regarding shielding performance, such as... Figure 6 As shown, a shielding effect of more than 30 dB is exhibited in the frequency band above 50 kHz. Similarly, the conductive nonwoven fabric and conductive nonwoven tape according to each of Examples 2 and 3 were evaluated as "excellent" in terms of plating treatment, shielding performance and ease of use of the tape, and exhibited a shielding effect of more than 30 dB in the frequency band above 50 kHz.

[0049] As described above, in Comparative Examples 1 to 3, the conductive nonwoven fabric and conductive nonwoven tape were evaluated as "inferior" in any of the aspects of plating treatment, shielding performance, and ease of use, while in Examples 1 to 3, the conductive nonwoven fabric and conductive nonwoven tape were evaluated as "superior" in terms of plating treatment, shielding performance, and ease of use. Therefore, it was found that the performance of the conductive nonwoven fabric and conductive nonwoven tape differs depending on the initial specifications of the nonwoven fabric. In particular, it was found that in the initial specifications of the nonwoven fabric, thickness and density are likely to affect the coating weight when forming the plating portion, and the most preferred initial specifications of the nonwoven fabric are a thickness of 0.30 mm or more and 1.00 mm or less, and 0.2 g / cm³. 3 Above and 0.4 g / cm 3 The following densities.

[0050] In this manner, in the conductive nonwoven fabric 21 according to this embodiment, the weight per unit area of ​​the plated portion 21b is 30 g / m². 2 Above and 96 g / m 2 Therefore, the amount of conductive metal in the plated portion 21b is optimized. When the amount of metal is excessively increased, the conductive nonwoven fabric 21 becomes too stiff, and the shielding effect becomes insufficient. The amount of metal also cannot be significantly reduced. Therefore, a conductive nonwoven fabric 21 can be provided that can be properly placed on the wire 10 and can appropriately exhibit a shielding effect.

[0051] Furthermore, according to the pretreatment method of the conductive nonwoven fabric 21 in this embodiment, a thickness of 0.30 mm or more and 1.00 mm or less, and a density of 0.2 g / cm³ are prepared in the initial state. 3 Above and 0.4 g / cm 3 The nonwoven fabric 21a of the following density is pretreated by coating it with supercritical carbon dioxide to dissolve the organometallic complex 30. Therefore, by using the pretreated nonwoven fabric 21a, a suitable conductive nonwoven fabric 21 can be obtained. Thus, a pretreatment method for conductive nonwoven fabric 21 can be provided, which can be well placed on the wire 10 and can appropriately exhibit a shielding effect.

[0052] Furthermore, according to the conductive nonwoven fabric 21, conductive nonwoven tape 20, or wire harness 1 of this embodiment, a method for manufacturing the conductive nonwoven fabric 21 can be provided, which can be well disposed on the wire 10 and can appropriately exhibit a shielding effect. A method for manufacturing the conductive nonwoven tape 20 or a method for manufacturing the wire harness 1 can also be provided.

[0053] Although the present disclosure has been described above based on embodiments, the present disclosure is not limited to the above embodiments and modifications can be made without departing from the spirit of the present disclosure. Although non-electrolytic plating was performed in the embodiments, electrolytic plating can also be performed after non-electrolytic plating, and, where possible, known or publicly known techniques can be appropriately combined.

[0054] For example, in this embodiment, the wire harness 1 includes wires 10 and conductive nonwoven fabric tape 20. However, this disclosure is not limited thereto, and the wire harness 1 may also include other components such as corrugated outer casing components, other wires outside the conductive nonwoven fabric tape 20, etc.

[0055] In addition, the conductive nonwoven tape 20 is wrapped around the wire 10 in a semi-wrap manner, but the present invention is not particularly limited to semi-wrap.

Claims

1. A conductive nonwoven fabric, comprising: Non-woven fabric; as well as The plated portion is made of conductive metal and covered by fibers constituting the nonwoven fabric. The weight per unit area of ​​the plated portion is 30 g / m². 2 Above and 96 g / m 2 the following.

2. A pretreatment method for conductive nonwoven fabric, comprising: The first step involves preparing a material 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 Above and 0.4 g / cm 3 The following non-woven fabrics; The second step involves loading the nonwoven fabric prepared in the first step into a treatment tank, wherein the treatment tank contains an organometallic complex that is soluble in carbon dioxide under supercritical conditions. The third step involves supplying supercritical carbon dioxide to the treatment tank containing the nonwoven fabric from the second step, and setting the interior of the treatment tank to an environment with a pressure of 12 MPa or higher and 15 MPa or lower, and a temperature of 100°C or higher and 130°C or lower; The fourth step involves supplying the supercritical carbon dioxide and setting the environment in the third step, and then removing the nonwoven fabric from the processing tank after a period of 10 to 60 minutes.

3. A method for manufacturing a conductive nonwoven fabric, comprising: The fifth step involves applying a non-electrolytic plating process to the non-woven fabric taken out in the fourth step of the pretreatment method for the conductive non-woven fabric according to claim 2, thereby obtaining the conductive non-woven fabric.

4. A method for manufacturing a conductive nonwoven tape, comprising: The sixth step is to form an adhesive layer on the conductive nonwoven fabric obtained in the fifth step of the method for manufacturing the conductive nonwoven fabric according to claim 3.

5. A method for manufacturing a wire harness, comprising: The seventh step involves winding the conductive nonwoven tape, obtained by forming an adhesive layer in the sixth step of the method for manufacturing the conductive nonwoven tape according to claim 4, onto the wire.

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