JP2017069094A - Conductive tape, and production method of conductive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive tape which has low electric resistance, excellent peel strength, and excellent anti-repulsion property.SOLUTION: A conductive tape 1 is formed by laminating a pressure-sensitive adhesive layer 2 which covers a conductive mesh 3 and contains conductive fillers 4 with average particle diameter of 2.5-30 μm and a metal foil 5. Thereby the number of contact points between the conductive mesh 3 and the conductive fillers 4 during conduction time increases, and consequently electric resistance of the conductive tape 1 can be reduced. Besides peel strength of the conductive tape 1 can be improved because reduction of a portion adhering to an adherend can be prevented. Further, anti-repulsion property of the conductive tape 1 can be improved because repulsion generated by folding the conductive tape 1 is prevented from becoming excessively large.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a conductive tape in which an adhesive layer that covers a conductive mesh and contains a conductive filler and a metal foil are laminated, and a method for manufacturing the conductive tape.

  FIG. 9 is a plan view showing an example of a conventional conductive tape. 10 is an X1-X1 ′ cross-sectional view of the conductive tape shown in FIG. 9. 11 is a cross-sectional view of the conductive tape shown in FIG. 9 taken along the line X2-X2 '. For example, Patent Document 1 includes a conductive mesh fabric 101 having a metal film on the surface, and an adhesive film 102 made of an adhesive formed only on an opening of the conductive mesh fabric 101, and the conductive mesh fabric 101. A conductive tape 100 is disclosed in which the metal film is exposed without being covered with an adhesive film on both sides. Patent Document 2 discloses a conductive pressure-sensitive adhesive sheet in which a conductive pressure-sensitive adhesive layer containing conductive particles is provided on both surfaces of a conductive substrate.

JP 2013-18856 A JP 2014-56967 A

  In recent years, there has been a demand for a conductive tape having a low electrical resistance value and good peel strength and repulsion resistance.

  In the conductive tape 100 described in Patent Document 1, since the adhesive film 102 is formed only on the opening of the conductive mesh fabric 101, when the adhesive film 102 is attached to the adherend, the adhesive portion to the adherend If the amount is small, sufficient peel strength may not be obtained. In addition, the conductive tape 100 described in Patent Document 1 has a high electrical resistance value because a conductive area with the adherend cannot be sufficiently obtained due to the structure of the conductive mesh fabric 101.

  Since the conductive adhesive sheet described in Patent Document 2 has a conductive adhesive layer laminated on both sides of the conductive substrate, the conductive adhesive layer is used when the thickness of the conductive adhesive sheet is to be reduced. The thickness of the must be reduced. As a result, the amount of conductive particles in the conductive pressure-sensitive adhesive layer is reduced, so that the conductivity of the conductive pressure-sensitive adhesive sheet is lowered. That is, the electrical resistance value becomes high.

  The present invention has been proposed in view of such a conventional situation, and provides a conductive tape having a low electrical resistance value and good peel strength and repulsion resistance.

  The conductive tape according to the present invention is formed by coating a conductive mesh and laminating an adhesive layer containing a conductive filler having an average particle diameter of 2.5 to 30 μm and a metal foil.

  The method for producing a conductive tape according to the present invention includes a step of forming a pressure-sensitive adhesive layer containing a conductive filler having an average particle size of 2.5 to 30 μm on a release substrate, and a conductive mesh covering the pressure-sensitive adhesive layer. And a step of attaching a metal foil to a surface opposite to the surface on which the release substrate of the adhesive layer coated with the conductive mesh is provided.

  According to the present invention, since the number of contacts at the time of conduction between the conductive mesh and the conductive filler is increased, the electrical resistance value of the conductive tape can be lowered. Moreover, according to this invention, since the adhesion part to a to-be-adhered body can be prevented from decreasing, the peeling strength of an electroconductive tape can be made favorable. Furthermore, according to this invention, it can suppress that the repulsion when a conductive tape is bent becomes large too much. That is, the resilience resistance of the conductive tape can be improved.

FIG. 1 is a plan view showing an example of a conductive tape. FIG. 2 is a cross-sectional view taken along the line A-A ′ of the conductive tape shown in FIG. 1. FIG. 3 is a B-B ′ cross-sectional view of the conductive tape shown in FIG. 1. FIG. 4 is a cross-sectional view showing a state where the conductive tape is attached to the adherend. FIG. 5 is a cross-sectional view showing an example of a process for forming an adhesive layer on a release substrate. FIG. 6 is a cross-sectional view showing an example of a process of covering the conductive mesh with the adhesive layer. FIG. 7 is a cross-sectional view showing an example of a step of attaching a metal foil to the surface opposite to the surface on which the release substrate of the adhesive layer is provided. FIG. 8 is a cross-sectional view for explaining a method for evaluating the resilience of a conductive tape, (A) is a cross-sectional view showing an example of a state in which a conductive tape is attached to an adherend, and (B ) Is a cross-sectional view showing an example of the case where there is no lifting in the part where the conductive tape is attached after being placed under a high temperature and high humidity condition, and (C) is a view of the conductive tape after being placed under a high temperature and high humidity condition. It is sectional drawing which shows an example when a float generate | occur | produces in the sticking part. FIG. 9 is a plan view showing an example of a conventional conductive tape. 10 is an X1-X1 ′ cross-sectional view of the conductive tape shown in FIG. 9. 11 is a cross-sectional view of the conductive tape shown in FIG. 9 taken along the line X2-X2 '.

Hereinafter, embodiments of the present invention will be described in detail in the following order.
1. 1. Conductive tape 2. Manufacturing method of conductive tape Example

<Conductive tape>
FIG. 1 is a plan view showing an example of the conductive tape 1. FIG. 2 is a cross-sectional view taken along the line AA ′ of the conductive tape 1 shown in FIG. 3 is a cross-sectional view taken along the line BB ′ of the conductive tape 1 shown in FIG. As for the conductive tape 1, the peeling base material 6, the adhesion layer 2, and the metal foil 5 are laminated | stacked in this order.

[Adhesive layer]
The pressure-sensitive adhesive layer 2 can be formed using, for example, a pressure-sensitive adhesive that is used as a conductive pressure-sensitive adhesive for conventional shield tapes. Adhesives are, for example, rubber adhesives, acrylic adhesives, silicone adhesives, urethane adhesives, vinyl alkyl ether adhesives, polyvinyl alcohol adhesives, polyvinyl pyrrolidone adhesives, polyacrylamide adhesives. Cellulose-based pressure-sensitive adhesives and the like can be used, and rubber-based pressure-sensitive adhesives and acrylic pressure-sensitive adhesives are generally used. The pressure-sensitive adhesive may contain a crosslinking agent. As the crosslinking agent, for example, an isocyanate crosslinking agent, an epoxy crosslinking agent, a chelating crosslinking agent, or the like can be used. As an isocyanate type crosslinking agent, aromatic isocyanate, alicyclic isocyanate, aliphatic isocyanate, etc. are mentioned, for example.

  The adhesive layer 2 covers the conductive mesh 3. That is, the conductive mesh 3 is not exposed from the one surface 2a of the pressure-sensitive adhesive layer 2 on the peeling substrate 6 side and the other surface 2b of the pressure-sensitive adhesive layer 2 on the metal foil 5 side. When the adhesive layer 2 covers the conductive mesh 3, for example, when the peeling substrate 6 is peeled off and one surface 2 a of the adhesive layer 2 is attached to the adherend, the conductive mesh 3 is removed from the one surface 2 a of the adhesive layer 2. It is possible to prevent the adhesion portion from being reduced due to the exposure of. Therefore, the peel strength of the conductive tape 1 can be improved.

  The thickness of the adhesive layer 2 is larger than the thickness of the conductive mesh 3 (the mesh diameter T1 shown in FIG. 2 and the thickness T2 where the warp and the weft cross in FIG. 3 intersect), for example, the conductive mesh 3 The mesh diameter T1 can be 103% to 134%. As an example, when the mesh diameter T1 of the conductive mesh 3 is 30 μm, the thickness of the adhesive layer 2 can be 31 to 40 μm. Moreover, it is preferable that the thickness of the adhesion layer 2 is larger than the average particle diameter of the conductive filler 4 whose average particle diameter mentioned later is 2.5-30 micrometers. That is, the average particle diameter of the conductive filler 4 is preferably smaller than the thickness of the adhesive layer 2. When the thickness of the pressure-sensitive adhesive layer 2 is larger than the average particle diameter of the conductive filler 4, for example, when the peeling substrate 6 is peeled off and one surface 2a of the pressure-sensitive adhesive layer 2 is applied to the adherend, It is possible to prevent a decrease in the adhesion portion due to the conductive filler 4 being exposed too much from the one surface 2a. Therefore, the peel strength of the conductive tape 1 can be improved.

[Conductive mesh]
As the conductive mesh 3, for example, a mesh fabric having a metal film formed on the surface thereof can be used. From the viewpoint of thinness and flexibility, the conductive mesh preferably has a metal film formed on the surface of a mesh fabric that includes at least a portion of thermoplastic synthetic fiber monofilament yarn. The metal film can be formed by a known technique such as vapor deposition, sputtering, electroplating, electroless plating, or the like.

  The fibers used for the thermoplastic synthetic fiber monofilament yarn include polyester (polyethylene terephthalate, polybutylene terephthalate, etc.), polyamide (nylon 6, nylon 66, etc.), polyolefin (polyethylene, polypropylene, etc.), polyacrylonitrile, polyvinyl. Examples thereof include alcohol-based and polyurethane-based fibers, and polyester-based fibers are preferable from the viewpoint of processability and durability. The said fiber may be used individually by 1 type, and may be used in combination of 2 or more type.

  The thermoplastic synthetic fiber monofilament yarn is preferably a flat yarn. The flatness ratio of the flat yarn can be 1.1 to 3.0, and can also be 1.1 to 2.5. The flatness refers to a value obtained by dividing the long side a of the rectangle by the short side b when drawing a rectangle circumscribing the cross-sectional shape of the monofilament yarn.

  When yarns other than thermoplastic synthetic fiber monofilament yarns are mixed, the fiber material is not particularly limited, and natural fibers and semi-synthetic fibers can be used in addition to synthetic fibers.

  The structure of the mesh fabric is not particularly limited, and examples thereof include plain weave, satin weave, twill weave, etc. Plain weave is preferable from the viewpoint of high binding strength of warp and weft and excellent strength.

  The conductive mesh 3 is a woven fabric having more openings than a general woven fabric, and warps and wefts are arranged at a predetermined distance apart. Therefore, the conductive mesh 3 has intersections of warps and wefts (intersection and overlapping portions), but there are many portions where warps and wefts do not intersect (do not overlap) as compared with general fabrics. The aperture ratio of the conductive mesh 3 can be set to 45 to 90%, for example. The aperture ratio means the ratio of the area of the opening per unit area when the conductive mesh 3 is projected onto a plane.

[Conductive filler]
As the conductive filler 4, a known conductive filler or carbon black generally used for conductive adhesives can be used. For example, use metal powder such as nickel, silver, copper, metal coat metal powder such as silver coat nickel, silver coat copper, metal coat resin powder, spherical conductive particles used for anisotropic conductive adhesive, etc. Can do. In particular, the conductive filler preferably contains at least one of nickel and silver-coated nickel, and more preferably contains silver-coated nickel. When the conductive filler 4 contains at least one of nickel and silver-coated nickel (preferably silver-coated nickel), the electrical characteristics of the conductive tape 1 can be further improved. The resistance value can be reduced more effectively. The conductive filler 4 may be used alone or in combination of two or more.

  The average particle diameter of the conductive filler 4 is 2.5 to 30 μm, and preferably 10 to 30 μm. When the conductive filler 4 has an average particle diameter of 2.5 μm or more, in the manufacturing process of the conductive tape 1, for example, when the conductive mesh 3 is coated on the adhesive layer 2 containing the conductive filler 4, pressurization is performed. This makes it easier for the conductive filler 4 to enter the opening of the conductive mesh 3. Thereby, for example, as shown in FIG. 2, the conductive filler 4 is easily interposed between the conductive mesh 3 and the metal foil 5, and the number of contacts at the time of conduction between the conductive mesh 3 and the conductive filler 4 can be increased. The electrical resistance value of the conductive tape 1 can be lowered. Moreover, when the average particle diameter of the conductive filler 4 is 30 μm or less, for example, when the peeling substrate 6 is peeled off and one surface 2a of the adhesive layer 2 is attached to the adherend, one surface of the adhesive layer 2 Since the decrease of the adhesion part due to the conductive filler 4 being excessively exposed from 2a can be prevented, the peel strength of the conductive tape 1 can be improved. Furthermore, since the average particle diameter of the conductive filler 4 is 30 μm or less, when the conductive tape 1 is bent, repulsion due to the conductive filler 4 being located in the bent portion can be suppressed. The rebound resistance of 1 can be improved.

  Moreover, it is preferable that the average particle diameter of the conductive filler 4 is smaller than the thickness of the conductive mesh 3 (the above-described mesh diameter T1 and the thickness T2 where the warp and the weft intersect). By adopting such a configuration, for example, when the conductive mesh 3 is coated on the adhesive layer 2 containing the conductive filler 4, the conductive filler 4 easily enters the opening of the conductive mesh 3 by pressurization. As a result, for example, as shown in FIG. 2, the conductive filler 4 is easily interposed between the conductive mesh 3 and the metal foil 5, and the number of contacts at the time of conduction between the conductive mesh 3 and the conductive filler 4 is further increased. The electrical resistance value of the conductive tape 1 can be lowered more effectively. Moreover, it is preferable that the lower limit of the average particle diameter of the electroconductive filler 4 is 8% or more with respect to the mesh diameter T1 (refer FIG. 2) of the electroconductive mesh 3, for example. By setting it as such a structure, since the contact at the time of conduction | electrical_connection with the electroconductive mesh 3 and the electroconductive filler 4 tends to increase, the electrical resistance value of the electroconductive tape 1 can be lowered more effectively.

  The content of the conductive filler 4 in the adhesive layer 2 is preferably 10 to 20% by mass. When using 2 or more types of electroconductive fillers 4 together, it is preferable that the total amount satisfy | fills the range of the said content. By setting the content of the conductive filler 4 in the adhesive layer 2 to 10% by mass or more, it is possible to prevent the contacts at the time of conduction between the conductive mesh 3 and the conductive filler 4 from being excessively reduced. The electrical resistance value of the conductive tape 1 can be lowered. Moreover, since it can prevent that the quantity of the adhesive in the adhesion layer 2 decreases too much by making content of the conductive filler 4 in the adhesion layer 2 into 20 mass% or more, the peeling strength of the conductive tape 1 Can be improved.

[Metal foil]
The metal foil 5 is formed for the purpose of eliminating the adhesiveness on one side of the conductive tape 1 or for reducing the electric resistance value in the thickness direction (lamination direction) of the conductive tape 1. As the metal foil 5, for example, a metal material used for a conventional electromagnetic wave shielding tape can be applied. The material which comprises the metal foil 5 can mention copper, aluminum, nickel, gold | metal | money, silver etc., for example, These may be used individually by 1 type and may use 2 or more types together. In particular, as the metal foil 5, it is preferable to use a copper foil from the viewpoints of availability, mechanical strength, heat resistance, cost, rust prevention, and the like.

  The thickness of the metal foil 5 is preferably 5 to 25 μm, and more preferably 7 to 12 μm. By setting it as such thickness, the electrical property of the conductive tape 1, mechanical strength, shape followability, shape stability, etc. can be made favorable.

[Peeling substrate]
For example, PET (Poly Ethylene Terephthalate), OPP (Oriented Polypropylene), PMP (Poly-4-methlpentene-1), PTFE (Polytetrafluoroethylene), or the like can be used as the release substrate 6.

  As described above, the conductive tape 1 according to the present embodiment is formed by laminating the adhesive layer 2 containing the conductive filler 4 and the metal foil 5 while covering the conductive mesh 3. By setting it as such a structure, since the contact at the time of conduction | electrical_connection with the electroconductive mesh 3 and the electroconductive filler 4 increases, the electrical resistance value of the electroconductive tape 1 can be made low. Moreover, since it can prevent that the adhesion part to a to-be-adhered body reduces, the peeling strength of the electroconductive tape 1 can be made favorable. Furthermore, it can suppress that the repulsion when the electroconductive tape 1 is bent becomes large too much.

  FIG. 4 is a cross-sectional view showing a state where the conductive tape 1 is attached to the adherend 7. For example, the conductive tape 1 described above can be shielded against electromagnetic waves by peeling the peeling substrate 6 during use and bonding one surface 2a of the adhesive layer 2 to an adherend 7 (for example, an electronic device casing). Can function as a tape. In addition, although the conductive tape 1 mentioned above was demonstrated as a thing provided with the peeling base material 6, the peeling base material 6 does not need to be provided.

<Method for producing conductive tape>
The method for producing a conductive tape according to the present embodiment includes a step of forming the above-mentioned adhesive layer 2 on the peeling substrate 6, a step of covering the conductive mesh 3 with the adhesive layer 2, and a coating of the conductive mesh 3. A step of bonding the metal foil 5 to the other surface 2b opposite to the one surface 2a on which the release substrate 6 of the adhesive layer 2 is provided. Hereinafter, each process will be described with reference to the drawings.

[Step of forming an adhesive layer on a release substrate]
FIG. 5 is a cross-sectional view showing an example of a process for forming the adhesive layer 2 on the release substrate 6. For example, the pressure-sensitive adhesive layer 2 can be formed by applying a pressure-sensitive adhesive composition containing the conductive filler 4 onto the release substrate 6. As a coating method, for example, a coating method or an extrusion method can be used. The thickness of the pressure-sensitive adhesive layer 2 may be a thickness that allows the conductive mesh 3 to be covered with the pressure-sensitive adhesive layer 2 in the step of covering the conductive mesh 3 described later with the pressure-sensitive adhesive layer 2. The thickness of the adhesive layer 2 may be 76% to 120% with respect to the mesh diameter T1 of the conductive mesh 3, for example. As an example, when the mesh diameter T1 of the conductive mesh 3 is 30 μm, the thickness of the adhesive layer 2 can be set to 23 to 35 μm.

[Step of covering the conductive mesh with the adhesive layer]
FIG. 6 is a cross-sectional view showing an example of a process for covering the conductive mesh 3 with the adhesive layer 2. For example, the conductive mesh 3 can be covered with the adhesive layer 2 by bonding the conductive mesh 3 to the adhesive layer 2 using a laminator. The pressure (linear pressure) applied when the conductive mesh 3 is bonded to the adhesive layer 2 is determined in consideration of covering the adhesive mesh 2 with the conductive mesh 3 and preventing air from being caught in the adhesive layer 2, etc. For example, it is preferable to set it as 1-30 kg / 10mm. Specific examples of the laminator include a metal roll, a rubber roll, and a combination of a metal roll and a rubber roll.

[Process of attaching metal foil]
FIG. 7 is a cross-sectional view showing an example of a step of bonding the metal foil 5 to the other surface 2b opposite to the one surface 2a on which the release substrate 6 of the adhesive layer 2 is provided. For example, the metal foil 5 is bonded to the other surface 6b of the peeling substrate 6 using a laminator. The pressure (linear pressure) applied when the metal foil 5 is bonded to the adhesive layer 2 is, for example, 1 to 30 kg / 10 mm in consideration of preventing air entrainment into the adhesive layer 2. preferable.

  Through the above-described steps, the conductive tape 1 is obtained in which the peeling base 6, the adhesive layer 2 that covers the conductive mesh 3 and contains the conductive filler 4, and the metal foil 5 are laminated in this order. be able to.

  In the method for manufacturing a conductive tape according to the present embodiment, when the conductive mesh 3 is coated on the adhesive layer 2 containing the conductive filler 4, the conductive filler 4 enters the opening of the conductive mesh 3 by pressurization. It becomes easy. Thereby, since the contact at the time of conduction | electrical_connection with the electroconductive mesh 3 and the electroconductive filler 4 can be increased, the electrical resistance value of the electroconductive tape 1 can be made low.

  In addition, as a manufacturing method of the conductive tape 1, other methods than the above-described methods, for example, a method of forming the adhesive layer 2 on the metal foil 5 and then covering the conductive mesh 3 with the adhesive layer 2 can be considered. However, in this method, for example, when the metal foil 5 is a copper foil, wrinkles are easily formed, and it is difficult to form the adhesive layer 2 on the metal foil 5. In addition, since it is difficult to embed the conductive mesh 3 in the adhesive layer 2, it is not possible to increase the contact points when the conductive mesh 3 and the conductive filler 4 are conductive as in the conductive tape 1 described above. It becomes difficult to reduce the electrical resistance value of the conductive tape 1. Therefore, it is preferable to apply the conductive tape manufacturing method according to the above-described embodiment.

  Examples of the present invention will be described below. In this example, a conductive tape in which an adhesive layer and a metal foil were laminated was produced, and the electrical resistance value, appearance, peel strength, and resilience resistance of the produced conductive tape were evaluated. The present invention is not limited to these examples.

[Example 1]
100 parts by weight of an adhesive made of a copolymer of butyl acrylate, acrylic acid, and 2-hydroxyethyl methacrylate, and nickel powder (average particle size: 30.0 μm, manufactured by Vale Co., Ltd.) as a conductive filler 10-20 mass parts and 1 mass part of crosslinking agents (isocyanate type crosslinking agent) were mix | blended, and the adhesive composition was prepared.

  Next, an adhesive layer having a thickness of 30 μm was formed by applying the adhesive composition on a PET film (thickness: 38 μm).

  Next, using a laminator, a conductive mesh (mesh diameter T1: 30 μm, width: 250 mm, manufactured by Seiren Co., Ltd.) was bonded to the adhesive layer at a linear pressure of 5 kg / 10 mm (see FIG. 6). Thereby, the adhesion layer was coat | covered with the electrically conductive mesh.

  A copper foil (thickness 12 μm) was bonded to the other surface opposite to the one surface of the PET film-side adhesive layer using a laminator at a linear pressure of 5 kg / 10 mm (see FIG. 7). Thereby, the electroconductive tape was obtained (refer FIGS. 1-3).

[Example 2]
In Example 2, instead of nickel powder having an average particle diameter of 30.0 μm, an equivalent amount of silver-coated nickel (average particle diameter of 25.0 μm, manufactured by Nikko Rica Co., Ltd.) was used. A conductive tape was obtained in the same manner as above.

[Example 3]
In Example 3, a conductive tape was obtained in the same manner as in Example 1 except that an equivalent amount of nickel powder with an average particle diameter of 25.0 μm was used instead of nickel powder with an average particle diameter of 30.0 μm. It was.

[Example 4]
In Example 4, a conductive tape was obtained in the same manner as in Example 1 except that an equivalent amount of nickel powder having an average particle diameter of 15.0 μm was used instead of nickel powder having an average particle diameter of 30.0 μm. It was.

[Example 5]
In Example 5, a conductive tape was obtained in the same manner as in Example 1 except that an equivalent amount of nickel powder having an average particle diameter of 11.4 μm was used instead of nickel powder having an average particle diameter of 30.0 μm. It was.

[Example 6]
In Example 6, a conductive tape was obtained in the same manner as in Example 1 except that an equivalent amount of nickel powder having an average particle diameter of 3.5 μm was used instead of nickel powder having an average particle diameter of 30.0 μm. It was.

[Example 7]
In Example 7, a conductive tape was obtained in the same manner as in Example 1 except that an equivalent amount of nickel powder having an average particle diameter of 2.5 μm was used instead of nickel powder having an average particle diameter of 30.0 μm. It was.

[Comparative Example 1]
In Comparative Example 1, a conductive tape was obtained in the same manner as in Example 1 except that an equivalent amount of nickel powder having an average particle diameter of 40.0 μm was used instead of nickel powder having an average particle diameter of 30.0 μm. It was.

[Comparative Example 2]
In Comparative Example 2, a conductive tape was obtained in the same manner as in Example 1 except that an equivalent amount of nickel powder having an average particle diameter of 1.0 μm was used instead of nickel powder having an average particle diameter of 30.0 μm. It was.

[Comparative Example 3]
In Comparative Example 3, a pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that nickel powder having an average particle size of 30.0 μm was not blended.

[Electric resistance value]
The conductive tape (25 mm × 25 mm) described above was attached to the end of a 1 mm thick copper plate (25 mm × 75 mm) as an electrode using a 2 kg hand roller. Further, another copper plate was placed as an electrode on the surface of the conductive tape, fixed with a fixing jig, and the copper plate of the electrode was connected with a milliohm meter, and the electric resistance value was read. Practically, the electrical resistance value is preferably less than 20.0 mΩ, and more preferably 15.0 mΩ. The results are shown in Table 1.

[appearance]
When the conductive filler is not visible from the PET film side of the conductive tape described above by visual inspection, the appearance is evaluated as “◯” (good), and when the conductive filler is visible from the PET film side of the conductive tape, The appearance was evaluated as “x” (defect). The results are shown in Table 1.

[Peel strength]
Using the 2 kg hand roller, the above-described conductive tape (20 mm × 100 mm) was attached to a glass plate as an adherend. After applying the conductive tape, it was left for 30 to 45 minutes. Thereafter, using a tensile tester, the conductive tape was pulled under conditions of a peeling rate of 300 mm / min and a peeling angle of 180 °, and the peel strength when the conductive tape was peeled off from the adherend was measured. The results are shown in Table 1.

[Rebound resistance]
FIG. 8 is a cross-sectional view for explaining a method for evaluating the resilience of a conductive tape. First, as shown in FIG. 8A, a conductive tape (10 mm × 70 mm) is formed in a U shape so as to cover one end of a glass plate (thickness: about 3 mm) as an adherend. Pasted on. Then, the adherend to which the conductive tape was attached was confirmed to be free from floating in the attached portion of the conductive tape after being placed under high temperature and high humidity conditions (temperature 60 ° C., relative humidity 90%) for 48 hours. . As shown in (B) of FIG. 8, when there was no lifting at the part where the conductive tape was applied, the repulsion resistance was evaluated as “◯”. Moreover, as shown to (C) in FIG. 8, when the floating part generate | occur | produced in the sticking part of an electroconductive tape, the resilience resistance was evaluated as "x". The results are shown in Table 1.

  The conductive tapes of Examples 1 to 7 are formed by laminating an adhesive layer containing a conductive filler having an average particle size of 2.5 to 30 μm and a metal foil while covering a conductive mesh. The resistance value was low, and the peel strength and resilience resistance were good. Moreover, the external appearance was also favorable.

  In particular, the conductive tapes of Examples 1 to 5 were found to have a lower electrical resistance value when the average particle size of the conductive filler was 10 to 30 μm.

  Moreover, from the results of Example 2 and Example 3, it was found that the use of silver-coated nickel as the conductive filler resulted in a lower electrical resistance value than when nickel was used as the conductive filler.

  On the other hand, it was found that the conductive tape of Comparative Example 1 in which the average particle size of the conductive filler exceeds 30 μm is not good in peel strength, resilience resistance and appearance. In the conductive tape of Comparative Example 1, since the average particle size of the conductive filler was larger than the thickness of the adhesive layer, the adhesion portion to the adherend decreased, and the peel strength was considered to have decreased. Further, in the conductive tape of Comparative Example 1, since the average particle size of the conductive filler was larger than the thickness of the adhesive layer, the repulsion at the bent portion when the conductive tape was bent was increased, and the conductive tape was attached to the adherend. It is thought that the floating of the time is likely to occur. Furthermore, since the conductive tape of Comparative Example 1 had an average particle size of the conductive filler larger than the thickness of the adhesive layer, it is considered that the conductive filler was easily visible from the PET film side.

  It was found that the electrical resistance value of the conductive tape of Comparative Example 2 in which the average particle size of the conductive filler was less than 2.5 μm was too high. This is probably because the average particle size of the conductive filler was too small with respect to the mesh diameter T1 of the conductive mesh, and the number of contacts at the time of conduction between the conductive mesh and the conductive filler decreased.

  It was found that the electrical resistance value of the conductive tape of Comparative Example 3 that does not contain a conductive filler having an average particle size of 2.5 to 30 μm is too high. This is considered to be because the conductivity in the thickness direction of the conductive tape decreased due to the absence of the conductive filler.

DESCRIPTION OF SYMBOLS 1 Conductive tape, 2 Adhesive layer, 3 Conductive mesh, 4 Conductive filler, 5 Metal foil, 6 Release base material, 7 Substrate, 100 Conductive tape, 101 Conductive mesh fabric, 102 Adhesive film

Claims (9)

An adhesive layer that covers the conductive mesh and contains a conductive filler having an average particle size of 2.5 to 30 μm;
A conductive tape made by laminating metal foil.   The conductive tape according to claim 1, wherein an average particle diameter of the conductive filler is smaller than a thickness of the adhesive layer.   The electroconductive tape of Claim 1 or 2 whose content of the electroconductive filler in the said adhesion layer is 10-20 mass%.   The conductive tape according to any one of claims 1 to 3, wherein an average particle diameter of the conductive filler is smaller than a thickness of the conductive mesh.   The conductive tape of any one of Claims 1-4 whose average particle diameter of the said conductive filler is 10-30 micrometers.   The conductive tape according to claim 1, wherein the conductive filler contains at least one of nickel and silver-coated nickel.   The conductive tape according to claim 1, wherein the conductive filler contains silver-coated nickel.   The conductive tape according to any one of claims 1 to 7, wherein the metal foil is a copper foil. Forming a pressure-sensitive adhesive layer containing a conductive filler having an average particle size of 2.5 to 30 μm on the release substrate;
Coating the adhesive layer on the conductive mesh;
The manufacturing method of an electroconductive tape which has the process of bonding metal foil to the surface on the opposite side to the surface in which the said peeling base material was provided of the adhesion layer which coat | covered the said electroconductive mesh.