JP7429982B2 - Static removal sheet - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge removal sheet that removes charge from components of a vehicle.

BACKGROUND ART Charge removal sheets that are attached to a vehicle body in order to remove static electricity from the vehicle body have been known (for example, Patent Documents 1 and 2).

International Publication WO2015/064195 Publication Utility model registration No. 3217483

The charge removal sheet attached to the vehicle body has sharp corners so that the charged charges are discharged from the sharp corners, so the more sharp corners there are, the more efficient the charge removal is. However, since the conventional charge removal sheet needs to have many sharp corners, there is a problem in that its shape is inevitably restricted.

The problem to be solved by the technology of the present specification has been made in view of the above-mentioned points, and aims to provide a charge removal sheet that has excellent charge removal efficiency and excellent shape freedom.

The charge removal sheet according to the embodiment of the present specification is attached to a component of a vehicle, and is characterized by having a nonwoven fabric containing conductive fibers as a base material.

According to the charge removal sheet according to the embodiment of the present specification, the base nonwoven fabric contains a large number of conductive fibers, and each end of the conductive fibers is capable of discharging electrical charges. Therefore, the charge removal sheet according to the embodiment can have excellent charge removal efficiency and excellent freedom in shape.

Here, in the charge removal sheet, the nonwoven fabric may contain 5% by mass or more of the conductive fibers.

According to this, it is possible to achieve excellent charge removal efficiency.

Moreover, in the above-mentioned charge removal sheet, the conductive fibers may be core-sheath structure conductive fibers having conductivity in the core portion.

According to this, the sheath portion covering the core portion of the core-sheath conductive fiber can have the same composition as the fibers constituting the nonwoven fabric, and the charge removal sheet can be made uniform.

Further, the above-mentioned charge removal sheet may contain colored resin fibers.

According to this, the charge removal sheet can be colored.

Moreover, in the above-mentioned charge removal sheet, a conductive adhesive layer can be provided on the back surface.

According to this, the charge removal sheet can be easily attached to a component of a vehicle.

Further, the charge removal sheet may have a resin-impregnated layer on the surface side.

According to this, unraveling of the surface of the charge removal sheet can be suppressed.

According to the charge removal sheet of the embodiment, it is possible to have excellent charge removal efficiency and excellent freedom in shape.

It is an image perspective view of the charge removal sheet of an embodiment. FIG. 3 is a diagram illustrating an image of airflow in a wind tunnel test of a bumper of a vehicle body to which a charge removal sheet of an embodiment is attached. FIG. 3 is a diagram illustrating an image of airflow in a wind tunnel test of a bumper on a vehicle body to which a static electricity removal sheet is not attached.

Hereinafter, a charge removal sheet according to an embodiment of the present specification will be described based on the drawings. Note that the scope of the present invention is not limited to the scope disclosed in the embodiments. The charge removal sheet 1 according to the embodiment is a sheet that has a nonwoven fabric 50 containing conductive fibers 10 as a base material, is attached to a vehicle body C that is a component of a vehicle, and discharges charges that have been charged on the vehicle body C.

The conductive fiber 10 is a conductive fiber, and in the embodiment, a core-sheath conductive fiber whose core portion is conductive, a metal-plated fiber whose surface is conductive, and a fiber whose fiber itself is conductive. metal fibers, etc. can be used. As the conductive fiber with a core-sheath structure, a general-purpose product can be used, and examples of the general-purpose product include Corebrid (manufactured by Mitsubishi Chemical Corporation) and Kura Carbo (manufactured by Kuraray Corporation). As the metal-plated fiber, a general-purpose product can be used, and examples of the general-purpose product include AGPOS (manufactured by Mitsufuji Co., Ltd.) and Odex (manufactured by Osaka Electric Industry Co., Ltd.). Moreover, as the metal fiber, a general-purpose product can be used, and examples of the general-purpose product include stainless wool (manufactured by Nippon Glass Fiber Industries Co., Ltd.) and metal wool (manufactured by J-Witex Co., Ltd.). In another embodiment, the conductive fiber 10 may be a core-sheath conductive fiber. This is because the sheath covering the core can have the same composition as the fibers constituting the nonwoven fabric 50, the conductive fibers 10 can be made inconspicuous, and the charge removal sheet can be made uniform. be.

In the embodiment, the thickness of the conductive fiber 10 can be 0.5 to 20 dtex in terms of fineness (dtex), which is the weight of 10,000 m of fiber. This is because a large number of ends of the conductive fiber 10 can be formed, and the efficiency of charge removal can be improved. When the fineness of the conductive fibers 10 is less than 0.5 dtex, although it is possible to form many ends of the conductive fibers 10, there is a risk that the production efficiency will be poor because the conductive fibers 10 are thin. On the other hand, if the fineness of the conductive fibers 10 exceeds 20 dtex, many ends of the conductive fibers 10 cannot be formed, and the efficiency of charge removal may be poor. As another embodiment, the fineness of the conductive fiber 10 may be 1 to 10 dtex, and as another embodiment, the fineness of the conductive fiber 10 may be 2 to 5 dtex.

In the embodiment, the length of the conductive fiber 10 can be 20 to 100 mm. This is because the nonwoven fabric 50 can be formed and the efficiency of charge removal can be excellent. When the length of the conductive fibers 10 is less than 20 mm, there is a possibility that the nonwoven fabric 50 cannot be formed because of the short length. On the other hand, if the length of the conductive fibers 10 exceeds 100 mm, it may be difficult to form the nonwoven fabric 50 due to the long length, and the number of ends of the conductive fibers 10 may decrease, resulting in poor charge removal efficiency. There is. In another embodiment, the length of the conductive fiber 10 can be between 25 and 90 mm, and in yet another embodiment between 30 and 80 mm.

The nonwoven fabric 50 of the embodiment can contain resin fibers 20 in addition to the conductive fibers 10. The resin fibers 20 can be colored with a pigment or the like, and can be colored to match the color of the vehicle body C. As the resin fiber 20, in the embodiment, polyester fiber, polyolefin fiber, polyamide fiber, acrylic resin fiber, polyvinyl alcohol fiber, etc. can be used. As another embodiment, the resin fiber 20 may be made of polyester resin having excellent strength and water resistance, and as another embodiment, PET (polyethylene terephthalate) resin, which is a polyester resin, may be used.

In the embodiment, the thickness of the resin fiber 20 can be 0.5 to 20 dtex in terms of fineness (dtex). This is because the nonwoven fabric 50 formed from the resin fibers 20 can be easily formed. If the fineness of the resin fibers 20 is less than 0.5 dtex, there is a risk that the production efficiency will be poor because the resin fibers are thin. On the other hand, if the fineness of the resin fibers 20 exceeds 20 dtex, the texture of the nonwoven fabric 50 may be poor because the resin fibers 20 are thick. As another embodiment, the fineness of the resin fibers 20 may be 1 to 10 dtex, and as yet another embodiment, the fineness of the resin fibers 20 may be 2 to 5 dtex.

In the embodiment, the length of the resin fiber 20 can be 20 to 100 mm. This is because the nonwoven fabric 50 can be easily formed. When the length of the resin fibers 20 is less than 20 mm, there is a possibility that the nonwoven fabric 50 cannot be formed because of the short length. On the other hand, if the length of the resin fibers 20 exceeds 100 mm, it may be difficult to form the nonwoven fabric 50 because of the length. In another embodiment, the length of the resin fiber 20 can be 25 to 90 mm, and in yet another embodiment, 30 to 80 mm.

The nonwoven fabric 50 of the embodiment may include a conductive adhesive layer 40 on the back surface. The conductive adhesive layer 40 is an adhesive layer for attaching the charge removal sheet 1 to the vehicle body C, and has conductivity. Since the conductive adhesive layer 40 has conductivity, the electric charge charged on the vehicle body C can be discharged from the charge removal sheet 1 via the conductive adhesive layer 40. As the conductive adhesive layer 40, a commercially available product can be used as an embodiment, and examples of commercially available products include conductive double-sided tape CN4490 (manufactured by 3M Japan Ltd.) and conductive double-sided tape 9711S (manufactured by 3M Japan Ltd.). , conductive aluminum foil double-sided tape 791 (manufactured by Teraoka Seisakusho Co., Ltd.), and conductive copper foil double-sided tape 792 (manufactured by Teraoka Seisakusho Co., Ltd.).

The charge removal sheet 1 of the embodiment may have a resin-impregnated layer 30 on the surface side of the nonwoven fabric 50. Thereby, unraveling of the surface of the charge removal sheet can be suppressed. The resin-impregnated layer 30 can be formed by impregnating the surface side of the nonwoven fabric 50 with a synthetic resin. In the embodiment, the synthetic resin may include acrylic resin, epoxy resin, vinyl acetate resin, and the like. As another embodiment, an acrylic resin with excellent weather resistance can be used as the synthetic resin. Further, in the embodiment, the synthetic resin may be an undiluted resin, an organic solvent-dispersed resin, or a water-dispersed resin (emulsion resin). In another embodiment, the synthetic resin may be a water-dispersed resin that is friendly to the working environment. Note that the resin-impregnated layer 30 is formed on the surface side of the charge removal sheet 1, so that it does not inhibit the conductivity of the charge removal sheet 1.

In the embodiment, the Tg (glass transition temperature) of the synthetic resin forming the resin-impregnated layer 30 can be set to -10 to 50°C. This is because appropriate flexibility can be imparted to the nonwoven fabric 50 having the resin-impregnated layer 30. When the Tg of the synthetic resin is less than -10°C, although it is possible to impart appropriate flexibility to the nonwoven fabric 50, the resin-impregnated layer 30 has stickiness and soot etc. There is a risk that dirt may become noticeable due to adhesion. On the other hand, when the Tg of the synthetic resin exceeds 50° C., the nonwoven fabric 50 having the resin-impregnated layer 30 becomes hard, and there is a possibility that it cannot be applied to the curved surface of the vehicle body C. In another embodiment, the Tg of the synthetic resin can be 0 to 40°C, and in yet another embodiment, 10 to 30°C.

Next, a method for manufacturing the charge removal sheet 1 according to the embodiment of this specification will be described. The method for manufacturing the charge removal sheet 1 includes a carding process in which the fibers used (conductive fibers 10, resin fibers 20) are dissolved to form a web (fibrous sheet), and the formed web is It consists of a needle punching process in which the fibers are entangled and bonded with each other using minute protrusions of needles to form the nonwoven fabric 50, and a thermocompression bonding process in which the conductive adhesive layer 40 is heat-sealed to the back side of the formed nonwoven fabric 50. . In addition, when manufacturing the charge removal sheet 1 having the resin-impregnated layer 30 on the surface side, a resin impregnation step of impregnating the surface side of the nonwoven fabric 50 with a synthetic resin may be provided after the needle punching step or the thermocompression bonding step. can.

In the carding process, conductive fibers 10 and resin fibers 20, which are raw materials for the nonwoven fabric 50, are mixed in a specific ratio, and a card processor is used to loosen and arrange the mixed fibers into a sheet-like mass to form a web. .

In the needle punching process, a needle (numerous needles arranged at right angles on one side of a flat plate) is repeatedly pressed against the web formed in the carding process at high speed, and the micro protrusions of the needles punch the fibers. The nonwoven fabric 50 is formed by entangling and bonding them together. In the embodiment, needle punching can be performed only on one side of the web (the side that becomes the back side of the nonwoven fabric 50). This is to form many ends of the conductive fibers 10 on the other surface of the web (the surface that becomes the surface of the nonwoven fabric 50).

In the thermocompression bonding process, the conductive adhesive layer 40 is heat-sealed to the back surface of the nonwoven fabric 50, and the conductive adhesive layer 40 is pressure bonded to the nonwoven fabric 50. Heat sealing can be performed at a temperature of 90 to 120° C., an actual pressure of 10 to 100 kPa applied to the sheet, and a time of 5 to 60 seconds.

In the resin impregnation step, a synthetic resin is spray-coated on the surface of the nonwoven fabric 50 to impregnate the nonwoven fabric 50 with the synthetic resin to form the resin-impregnated layer 30.

The charge removal sheet 1 manufactured in this way can be easily cut with a cutter knife or the like, and therefore has excellent flexibility in shape. By being attached to the surface of the vehicle body C, the charge removal sheet 1 can discharge positive charges accumulated on the vehicle body C. Therefore, when the vehicle body C to which the charge removal sheet 1 is attached is driven, it becomes difficult to generate a repulsive force between the positively charged air flow A (Fig. 2) and the air flow on the surface of the vehicle body. A becomes difficult to separate from the vehicle body C, and turbulence in the airflow A can be reduced.

Note that the charge removal sheet 1 formed from the nonwoven fabric 50 made of fibers can change its shape through elastic deformation, and can maintain its original shape as long as the elastic limit is not exceeded. Can be put on and taken off repeatedly. In other words, it is possible to repeatedly attach and detach the charge removal sheet 1 to and from the vehicle body C while checking the position where it is attached to the vehicle body C.

Hereinafter, the present invention will be explained in more detail with reference to Examples. The properties of the conductive fibers 10 and resin fibers 20 used are listed in Table 1, and the formulation of the charge removal sheet 1 of the example is listed in Table 2.

帯電除去シート１の性能評価は、車体Ｃと空気流Ａとの距離を測定することによって行なった。車体Ｃは、乗用車のフロントバンパを用い、フロントバンパの曲線部分に、上下１５０ｍｍ、前後５０ｍｍに裁断した帯電除去シート１を貼付したものを車体Ｃとして測定を行なった。測定は、帯電除去シート１が貼付されたフロントバンパを、風洞試験装置内に固定し、空気流Ａを風速６ｍ／ｓで風洞試験装置内に流し、スモークワイヤ法で煙を発生させ、空気流Ａを可視化させ、位置Ｐ（図２）での車体Ｃと空気流Ａとの距離を測定した。性能評価は、車体Ｃと空気流Ａとの距離を３回測定し、その平均値で評価した。もちろん、車体Ｃと空気流Ａとの距離が短いものが良好な結果となる。

Performance evaluation of the charge removal sheet 1 was performed by measuring the distance between the vehicle body C and the airflow A. The vehicle body C was measured by using a front bumper of a passenger car and attaching the charge removal sheet 1 cut to a length of 150 mm from top to bottom and 50 mm from front to back to the curved part of the front bumper. The measurement was carried out by fixing the front bumper to which the charge removal sheet 1 was attached in a wind tunnel test device, flowing air flow A into the wind tunnel test device at a wind speed of 6 m/s, generating smoke using the smoke wire method, and measuring the air flow. A was visualized and the distance between the vehicle body C and the airflow A at position P (FIG. 2) was measured. Performance evaluation was performed by measuring the distance between the vehicle body C and the air flow A three times and using the average value. Of course, the shorter the distance between the vehicle body C and the air flow A, the better the result.

(Example 1)
The charge removal sheet 1 of Example 1 was manufactured as follows. The nonwoven fabric 50 that is the base of the charge removal sheet 1 is prepared by mixing conductive fibers a and resin fibers a at a ratio of 5:95, dissolving the mixed fibers to form a sheet-like mass, and forming a web. The needle of a needle punch was repeatedly pressed against only one side of this web (the back side of the nonwoven fabric 50) at high speed, and the fine protrusions of the needle entangled and bonded the fibers to form the nonwoven fabric 50. . The basis weight of the nonwoven fabric 50 was 175 g/m ² . The charge removal sheet 1 is made by spray-coating a synthetic resin (acrylic emulsion (Tg: 12°C)) on the surface of a nonwoven fabric 50 to form a resin-impregnated layer 30 on the nonwoven fabric 50, and a conductive layer on the back side of the nonwoven fabric 50. The adhesive layer 40 was heat-sealed to form the charge removal sheet 1. Heat sealing was performed at a temperature of 100° C., an actual pressure of 52 kPa applied to the sheet, and a time of 10 seconds. Performance evaluation of the charge removal sheet 1 of Example 1 manufactured in this way was that the distance between the vehicle body C and the air flow A was 6.5 mm.

(Example 2)
The charge removal sheet 1 of Example 2 was formed under the same conditions as Example 1 except that the fibers were changed from Example 1 to a mixture of conductive fibers a and resin fibers B at a ratio of 50:50. It is something that Performance evaluation of the static charge removal sheet 1 of Example 2 manufactured in this manner was that the distance between the vehicle body C and the air flow A was 5.8 mm.

(Example 3)
The charge removal sheet 1 of Example 3 differs from Example 1 in that the fibers are changed to 100% conductive fiber A, the basis weight of the nonwoven fabric 50 is 200 g/m ² , and the resin-impregnated layer 30 is omitted. , was formed under the same conditions as in Example 1. Performance evaluation of the charge removal sheet 1 of Example 3 manufactured in this way was that the distance between the vehicle body C and the air flow A was 5.8 mm.

(Comparative example)
In the comparative example, the distance between the vehicle body C and the airflow A was measured using a vehicle body C (front bumper) to which the static charge removal sheet 1 was not attached. The distance between the vehicle body C and the air flow A was 14.4 mm.

FIG. 2 is a diagram showing an image of airflow A in a wind tunnel test of a bumper of a vehicle body C to which the charge removal sheet 1 of the example is attached. The charge removal sheet 1 makes it difficult for the air flow A on the surface of the vehicle body to separate from the vehicle body C. On the other hand, FIG. 3 is a diagram illustrating an image of airflow in a wind tunnel test of a bumper of a vehicle body C to which no charge removal sheet of a comparative example is attached. The positively charged airflow A is repelled by the vehicle body C, and the airflow A on the surface of the vehicle body is separated from the vehicle body C.

DESCRIPTION OF SYMBOLS 1... Charge removal sheet, 10... Conductive fiber, 20... Resin fiber, 30... Resin impregnated layer, 40... Conductive adhesive layer, 50... Nonwoven fabric, A... Air flow, C... Vehicle body, P... Position.

Claims (6)

1. A charge removal sheet that is attached to a component of a vehicle and has a single nonwoven fabric containing conductive fibers as a base material, and is needle-punched only on the back side of the nonwoven fabric . The charge removal sheet according to claim 1, wherein the nonwoven fabric contains the conductive fibers in an amount of 5% by mass or more. 2. The charge removal sheet according to claim 1, wherein the conductive fiber is a core-sheath conductive fiber having conductivity in its core. The charge removal sheet according to claim 1, characterized in that it contains colored resin fibers. The charge removal sheet according to claim 1, further comprising a conductive adhesive layer on the back surface. The charge removal sheet according to claim 1, having a resin-impregnated layer on the surface side.

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