JPH10334971A - Conductive adhesive tape and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive tape in which strong pressure-sensitive adhesion and low resistant continuity are ensured under a high pressurizing force by alternately juxtaposing and integrating a plurality of stripe conductive parts and stripe adhesive parts on one surface or both surfaces of a support base. SOLUTION: Stripe conductive parts 2 and stripe adhesive parts 3 are alternately juxtaposed on one surface or both surfaces of a support base 1. The stripe conductive parts 2 are formed by multiple applications of a conductive paste consisting of a mixture of a metal powder with a resin, and the stripe adhesive parts 3 are formed by multiple applications of an adhesive solution. This adhesive tape is manufactured by mounting a circular disc in which a plurality of adhesive sheets and conductive sheets are laminated and integrated on a lathe, rotating it, and continuously cutting the disc from the circumferential side with a flat bite in a fixed thickness. In order to prevent the adhesion of the adhesive sheet to the bite, it is effective to perform cutting while cooling with dry ice or liquid nitrogen. The conductive adhesive tape is usable in a wide range of fields because of its single-action property of conduction and connection and thin form.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive adhesive tape used for electrical conduction such as grounding.

[0002]

2. Description of the Related Art Metal particles are mixed as a conductive adhesive tape used for electrical continuity, for example, grounding of a printed circuit board, grounding of a shield case of electronic equipment, and grounding of a TV cathode ray tube. In the case where the adhesive is provided on one side of the conductive tape, the contact between the conductive portion and the metal particles in the adhesive layer is established between the conductive portion and the conductive tape → the adhesive layer. Mutual contact between metal particles inside → Electrical conductivity is achieved by mutual contact between the metal particles in the adhesive layer and the conductive tape, but moisture or gas adhering to the surface of the metal particles , The conductive adhesive tape
During storage or use of the lamp, it may be volatilized or gasified, the contact between the conductive particles may be weakened, and the resistance value may increase.

As a conductive adhesive tape which enables electrical conduction without depending on contact between metal particles in such an adhesive layer, an adhesive layer is provided on one surface of a metal foil and embossed. A metal foil is partially exposed to the surface of the pressure-sensitive adhesive layer, and the exposed metal foil portion is brought into contact with a conductive part and is adhesively fixed in the pressure-sensitive adhesive layer. Also, a plurality of bands are provided on a single-sided adhesive tape. Strip conductors are arranged side by side with a space between them, an adhesive layer is exposed between the conductors, and the juxtaposed conductors are brought into contact with a portion to be electrically connected and are adhesively fixed at an exposed portion of the adhesive layer (for example, JP-A-63-94700
No.) Also, as shown in the figure, a plurality of parallel conductors are embedded in the thermoplastic adhesive layer, and the conductors are brought into contact with the conductive parts by heating and pressing, and are fixed by melting and solidifying the thermoplastic adhesive. (For example, JP-A-1-195607)
Etc. are known.

[0004]

However, in the above-mentioned embossed conductive adhesive tape, the protrusion of the metal foil (usually 200 μm or less in thickness) has a hollow structure, and is easily crushed, so that the feeling of the pressure-sensitive adhesive is not good. If the pressing force is increased in order to effectively exert the pressure-bonding property, the protrusion is crushed, and it is not possible to expect a sufficiently strong adhesive fixing. Further, in the conductive adhesive tape of the above-mentioned strip conductor juxtaposition type, when the thickness of the conductor is large (thickness of about 200 μm), the step between the conductor surface and the surface of the pressure-sensitive adhesive layer becomes large, and the adhesive is stably fixed. Difficult to guarantee,
On the other hand, when the conductor thickness is reduced, an increase in conduction resistance is inevitable even if strong adhesive fixing can be expected. Further, in the above-mentioned conductive adhesive tape of the thermoplastic adhesive layer type, an adhesive film is easily interposed between a conductor and a portion to be connected, and electrical conduction with low resistance cannot be expected. SUMMARY OF THE INVENTION An object of the present invention is to provide a conductive adhesive tape capable of guaranteeing a strong pressure-sensitive adhesive under a high pressure and a low resistance conduction.

[0005]

According to a first aspect of the present invention, there is provided a conductive adhesive tape having a plurality of strip-like conductive portions and a strip-like adhesive portion alternately arranged on one or both sides of a supporting base material. It is a configuration characterized by being provided. A conductive adhesive tape according to a third aspect of the present invention is characterized in that a plurality of streak-like conductive portions and streak-like adhesive portions are alternately juxtaposed and integrated, and a manufacturing method thereof. Is characterized in that a circular disc formed by laminating and integrating a plurality of adhesive sheets and conductive sheets is rotated and continuously cut to a constant thickness from the outer peripheral side.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention. In FIG. 1, 1 is a supporting substrate. Reference numerals 2,... And 3,... Denote streak-like conductive portions and streak-like adhesive portions alternately arranged on one side of the support substrate 1, and streak-like conductive portions 2 are made of conductive paste (silver powder, nickel powder, copper powder). The streak-shaped adhesive portion 3 can be formed by multiple application of a pressure-sensitive adhesive solution. In FIG. 1, a indicates the width of the streak-like conductive portion 2, b indicates the width of the streak-like adhesive portion 3, and p indicates the parallel pitch.

[0007] In this multi-coating, two injection needle type discharge devices having a plurality of nozzles arranged side by side are arranged so that the positions of the nozzles are alternately arranged. And a conductive paste is discharged from the nozzle of one of the discharge devices in a multi-parallel streak having a width a and a pitch p on the traveling support base material, and the adhesive solution is discharged from the nozzle of the other discharge device. Discharge in the form of multiple parallel streaks with width b between the paste streaks,
Drying method, two T-die coaters having a comb-like shim incorporated in the exit gap of the T-die are arranged so that the positions of the shim partitions are alternately arranged.
A conductive paste is discharged from the die exit of one T-die coater onto the traveling support substrate in the form of multiple parallel stripes having a width a and a pitch p. A method of discharging the pressure-sensitive adhesive solution from the die outlet of the other T-die coater in a multi-parallel streak shape with a width b between the conductive paste streaks and then drying can be used.

FIG. 2A is a drawing showing the state of use of the conductive adhesive tape of the above embodiment, and FIG. 2B is a cross-sectional view taken along the line in FIG. The streaky conductive portions 2,... Are brought into contact with the portion X (Y) by pressure-sensitively bonding the streak-like adhesive portions 3,. In this case, even if the pressing force is large, unlike the case of the embossed projection, the conductive member does not collapse. Therefore, by applying a large pressure, the streak-like adhesive portion and each of the connected portions X, Y can be fixed with a sufficient pressure-sensitive adhesive force, and the streak-like adhesive portion can be fixed to each of the portions X, Y
Can be firmly contacted and fixed.

In the above, in order to increase the adhesive fixing force as much as possible, it is preferable that the width b of the streak-like adhesive portion is larger than the width a of the streak-like conductive portion. When the supporting base material 1 is an insulator, the resistance value of the electric conduction path is the connected portion X.
Are provided by the contact resistance between (Y) and the streak-like conductive portions 2, and the longitudinal resistance value of the streak-like conductive portions 2,. If the resistance value is to be lower than this resistance value, a conductive support substrate is used as the support substrate 1.

A plastic film (for example, a polyester film), a plastic non-woven fabric or a woven fabric can be used for the insulating support substrate.
Metal foil, metalized plastic film or non-woven fabric (metal-deposited plastic film, metal-plated plastic film or non-woven fabric or woven fabric, for example, electroless nickel-plated polyester satin woven fabric, metal foil laminated plastic film, etc.), metal fiber woven fabric, metal Plastic nonwoven fabric or woven fabric in which fibers are blended or blended can be used. When the condition of the conductance of the electrical conduction is satisfied only with the above-mentioned streaked conductive portion, as described above, it is possible to use the insulating supporting base material as the supporting base material. In this case, as shown in FIG. The streak-like conductive part 2 and the streak-like adhesive part 3
Can be firmly integrated to omit the support base material.

To manufacture the conductive adhesive tape shown in FIG. 3, a plurality of adhesive sheets 3 and a conductive sheet shown in FIG.
A circular disc made by laminating and integrating the tape 2 is mounted on a lathe and rotated, and continuously cut with a flat bite from the outer circumference to a constant thickness. During this time, adhesion of the adhesive sheet to the bite is prevented. For this purpose, it is effective to perform cutting while cooling with dry ice or liquid nitrogen. Aluminum foil, copper foil, iron foil, brass foil, nickel foil and the like can be used for the conductive sheet, but lead foil, solder foil (lead-tin alloy foil),
Casting sheet of metal paste (for example, silver paste)
Or a polyester paste obtained by applying a paste, a copper paste or a nickel paste on a polyester film treated with a silicone release agent) is excellent in machinability and is preferred.

In the above embodiment, the streak-like adhesive portion is used as the streak-like adhesive portion. However, a heat-bonding type streak-like adhesive portion may be used. In the above embodiment, the streak-like conductive portion and the streak-like adhesive portion are provided side by side only on one side of the support base material. However, the streak-like conductive portion and / or streak can also be provided on both sides. At least one of the material, width, and thickness of the shape-bonded portion may be different between both surfaces.
The normal size of each part of the conductive adhesive tape is usually such that the thickness of the streaky conductive part or the streaky adhesive part is 20 to 100 μm,
The width of the streak-like conductive portion is 30 to 300 μm, the width of the streak bonding portion is 50 to 500, and the thickness of the supporting base material is 10 to 1000 μm. The conductive adhesive tape according to the present invention also includes a wide sheet, and the tape can be formed by cutting the sheet.

The conductive adhesive tape according to the present invention can be used in a wide range of fields because of the one-touch property of conductive connection and thinness. For example, grounding for electromagnetic wave shielding and measures against static electricity, and small and thin electronic devices. It can be used for conduction between electrodes of components and lands on a circuit board.

[0014]

【Example】

Example 1 An acrylic pressure-sensitive adhesive having a width of 4 μm was applied to one side of a 38 μm-thick polyester film using a first T-die coater.
mm and a pitch of 5 mm, and a silver paste (Shintron conductive ink K-3080, trade name, manufactured by Shinto Paint Co., Ltd.) is applied to the uncoated portion having a width of 1 mm on the second T-die coater.
And then dried to obtain a conductive adhesive tape having a streak-like conductive portion and a streak-like adhesive portion having a thickness of 50 μm. Example 2 A composite sheet in which a 18 μm-thick copper foil was laminated on a 25 μm-thick polyester film was used as a support base material, and a streak-like conductive portion and a streak-like bond portion were formed on the copper foil. Other than the above, it was the same as Example 1. Example 3 500 μm thick solder foil having a thickness of 100 μm
m acrylic adhesive film, outer diameter 10
A cutout was cut out into a donut shape having a diameter of 0 mm and an inner diameter of 30 mm. Twenty-five of these were laminated, and a mandrel having a diameter of 30 mm was passed through the center hole of the laminate, and tightened with a nut. The tightened laminate was mounted on a lathe and cut into a continuous band having a thickness of 100 μm with a flat cutting tool while cooling with a dry ice methanol refrigerant to obtain a conductive adhesive tape (the width of the streaky conductive portion was 100 μm). ,
The width of the streaky adhesive portion is 500 μm).

Comparative Example An acrylic pressure-sensitive adhesive layer was provided on one side of a copper foil having a thickness of 38 μm, and a projection having a height of 40 μm and a spacing of 5 mm was formed on the copper foil by embossing to form a copper foil. The conductive adhesive tape was obtained by exposing the protrusions on the surface of the acrylic pressure-sensitive adhesive layer. For each of these examples and comparative examples (10 samples each),
A width of 1 mm is placed between electrodes of an acrylic resin plate (2 mm thick) in which copper foil electrodes having a width of 5 mm and a length of 25 mm are provided at a distance of 50 mm.
A 0 mm conductive adhesive tape is pasted over the electrode, and the resistance value immediately after pasting and 96 hours in a constant temperature and humidity chamber of 50 ° C. and 90 RH.
When the ratio (%) of the resistance value after standing for a time was measured, in the case of the examples, all were 150% or less, and the conductance was extremely stable. On the other hand, in the case of the comparative example, there was a case where the conductivity exceeded 150% and reached 500%, and the conductance was unstable.

[0016]

The conductive adhesive tape according to the present invention has the structure as described above. Even if the pressing force is increased in order to increase the pressure-sensitive adhesive force, the conductive tape in contact with the portion to be electrically connected can be used. Since the portion can be stably held without being crushed, the pressure can be increased and the adhesive can be firmly fixed. In addition, even if the number of streak-like adhesive portions is larger than that of streak-like conductive portions to enhance the adhesive fixing force,
By making the supporting base material conductive, a low resistance of electrical conduction can be guaranteed. Therefore, according to the present invention, a conductive adhesive tape that can guarantee excellent electrical conductivity and strong adhesive fixation.
Can be provided.

[Brief description of the drawings]

FIG. 1 is a drawing showing a conductive adhesive tape according to claim 1;

FIG. 2 is a view showing a use state of a conductive adhesive tape according to the present invention.

FIG. 3 is a view showing a conductive adhesive tape according to claim 3;

FIG. 4 is a view showing a circular disk used in the method for manufacturing a conductive adhesive tape according to claim 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Support base material 2 Streaked conductive part 3 Streaked adhesion part

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kunihiko Kaita, Inventor 1-11-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Naoki Matsuoka 1-1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Hirotaka Sato 1-2-1, Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation

Claims (4)

[Claims] 1. A conductive adhesive tape, wherein a plurality of streaky conductive portions and streak bonded portions are alternately arranged on one or both surfaces of a supporting base material. 2. The conductive adhesive tape according to claim 1, wherein the supporting substrate is a conductive substrate. 3. A conductive adhesive tape, wherein a plurality of streak conductive portions and streak adhesive portions are alternately arranged side by side and integrated. 4. A conductive material characterized in that a circular disk formed by laminating and integrating a plurality of adhesive sheets and conductive sheets is continuously cut from an outer peripheral side at a constant thickness. A method for producing an adhesive tape.