JPH08185714A - Conductive adhesive tape - Google Patents

Abstract

PURPOSE: To maintain stable electric conductivity in high-humidity atmosphere by providing a pressure-sensitive adhesive layer on one face of a base material, and providing conduction sections penetrating the adhesive layer and having terminal sections at the tips on the base material at desired intervals. CONSTITUTION: A pressure-sensitive adhesive layer 12 is provided on one face of the conducting tape base material 11 of a conducting adhesive tape main body 1, and conduction sections 110 penetrating the adhesive layer 12 and having terminal sections 111 at the tips are provided on the base material 11 at desired intervals. An auxiliary tape 2 has a pressure-sensitive adhesive layer 22 on one face of a tape base material 21, its tape width W2 is made wider than the width W1 of the tape main body 1, and the layer 22 is stuck to the surface of the base material 11 protrusively from both width ends of the main body 1. When the wide auxiliary tape 2 is stuck to the main body 1, the conduction stability in the high-temperature high-humidity environment can be guaranteed, and the reliability can be improved. The cut traces of drawing on the surface of the base material 11 are covered by the tape 2, and cut wounds of fingers at the time of sticking by hand can be surely excluded.

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 having conductivity in both the longitudinal direction and the thickness direction, for example, in the case of sticking over two places and electrically conducting between them. Is what you use.

[0002]

2. Description of the Related Art For electrical continuity, for example, grounding of a printed wiring board, grounding of an exterior shield case of an electronic device, grounding of a TV Braun tube, etc., a pressure-sensitive adhesive type conductive adhesive tape is applied. In some cases, grounding is performed by electrical conduction between the adhered surface and the conductive base material of the conductive adhesive tape and electrical conduction in the longitudinal direction of the conductive base material. As such a conductive adhesive tape, the applicant of the present invention states that "a metal foil and a pressure-sensitive adhesive layer provided on one side of the metal foil are provided, and the adhesive layer is coated on the adhesive layer side of the metal foil. Has been provided with a conducting portion penetrating the layer and having a terminal portion at the tip thereof at a desired interval "(Japanese Utility Model Publication No. 63-46980).

In this conductive adhesive tape, a pressure-sensitive adhesive layer is provided on one side of a metal foil, and a large number of protrusions are formed on the metal foil at desired intervals with a drawing margin larger than the thickness of the pressure-sensitive adhesive layer. It can be manufactured by drawing and then bending the tip of the protrusion to the outside with a press.In order to widen the surface area of the terminal part to reduce the electrical contact resistance, increase the drawing allowance and pressure sensitivity. It is effective to increase the protrusion height of the protrusion with respect to the adhesive layer surface and increase the bending allowance at the tip of the protrusion. However, if the projection drawing allowance is increased, the projection becomes open, and the entry of moisture or water through the hole easily causes rusting at the electrical contact portion of the terminal.
Notches are formed on the surface of the metal foil, and the fingers are likely to be cut when hand-applied. Therefore, the present inventors tried to protect the surface of the metal foil of the conductive adhesive tape by sticking a film.

[0004]

However, according to the experimental results of the present inventors, even under such protection,
In a high-humidity atmosphere, a considerable increase in electrical resistance at the contact portion of the terminal portion cannot be avoided. The cause is
With respect to the pressure applied for attaching the conductive adhesive tape, the compression elastic modulus of the conductive portion of the metal foil is considerably larger than that of the pressure-sensitive adhesive layer, and most of the pressing force is applied. It is difficult to apply a sufficient contact pressure between the pressure-sensitive adhesive layer and the surface to be adhered on the conductive portion of the metal foil, and as a result, the sealing property of the contact interface becomes insufficient, and this contact interface It is presumed that this is because rusting of electrical contact portions of the terminal portion is likely to occur due to intrusion of moisture and water from the inside. Therefore, when the adhered conductive adhesive tape was completely surrounded by an adhesive protection sheet to prevent the ingress of moisture and water from the contact interface, the increase of the electric resistance in the above humid atmosphere was observed. Could be effectively suppressed.

The object of the present invention is to build a pressure-sensitive adhesive layer on one side of a conductive tape substrate based on the results of such experiments, and to penetrate the adhesive layer on the substrate and to provide the tip thereof. Another object of the present invention is to improve a conductive adhesive tape in which conductive portions having terminal portions are provided at desired intervals to maintain stable electrical conductivity even in a humid atmosphere.

[0006]

A conductive adhesive tape according to the present invention has a pressure-sensitive adhesive layer provided on one surface of a conductive tape base material, and the base material penetrates the adhesive layer. And a pressure-sensitive adhesive layer on one surface of the tape base material on the other surface of the base material of the conductive adhesive tape body having a conductive portion at a desired interval with a terminal portion at its tip. The auxiliary tape has a constitution in which the auxiliary tape is projected from both ends of the width of the conductive adhesive tape main body and is bonded to the pressure-sensitive adhesive layer, and the tape base material of the auxiliary tape is provided. A material having a cushioning property can also be used as the material.

The construction of the conductive adhesive tape according to the present invention will be described below with reference to the drawings. FIG. 1A is an explanatory view showing a conductive adhesive tape according to the present invention, and FIG. 1B is a sectional view taken along the line RO in FIG. In (a) of FIG. 1 and (b) of FIG. 1, 1 is a conductive adhesive tape body, and a pressure-sensitive adhesive layer 12 is provided on one surface of a conductive tape base material 11, and its conductive A metal foil is usually used as the conductive tape base material 11, and the conductive tape base material 11 is used.
Is provided with a conductive portion 110 penetrating the pressure-sensitive adhesive layer 12 and having a terminal portion 111 at the tip thereof at desired intervals. The arrangement pattern of the conducting portions is a so-called scattered pattern, and as shown in FIG.
It is possible to use a row in which rows having a longitudinal arrangement interval of a are arranged at an interval of b and the rows adjacent to each other are shifted by a half pitch so that a and b are substantially equal. Reference numeral 2 denotes an auxiliary tape, which has a pressure-sensitive adhesive layer 22 on one surface of the tape base material 21, and the tape width w ₂ thereof is larger than the width w _{1 of the} conductive adhesive tape body 1 described above. The pressure sensitive adhesive layer 22 is attached to the surface of the conductive tape base material 11 of the conductive adhesive tape main body 1 so as to project from both width ends of the main body 1.

In the processing of the conducting portion 111, a punch-shaped male die and a die female die are used to draw a metal foil into a bottomless tubular shape (as shown in FIG. , The wall thickness becomes a little thinner), and then the tip of the tubular part is horizontally bent outward as shown in (b) of FIG. 2 to form the terminal part, or (a) of FIG. In addition, as shown in (b), a conical male die 31 and a conical hole female die 32 are used to overhang the metal foil with the male die and, as shown in (c) of FIG. It is possible to use a method of forming a hook-shaped terminal portion 111 by bending the portion with a female bottom. For the above-mentioned conductive tape base material, a metal having ductility capable of withstanding drawing or stretch forming, for example, a metal foil of aluminum, silver, iron, lead or the like is used. As the pressure-sensitive adhesive layer, a general-purpose pressure-sensitive adhesive layer such as an acrylic type, a rubber type, or a silicon type can be used.

As the tape base material of the above-mentioned auxiliary tape, a general-purpose solid plastic film such as polyester film and polypropylene film, and cushioning tape such as polyethylene and polypropylene as will be described later are used. Polyolefin type foams, urethane type foams, neoprene rubber type foams, polyvinyl chloride type foams, etc. are also used. In the above-mentioned auxiliary tape, the portions of the conductive adhesive tape body protruding from both ends of the width are adhered to the adherend so that the conductive tape base body and the conductive tape base of the conductive adhesive tape body are covered. The seal distance to the adhesive interface with the adherend is increased, the ingress of moisture and water to the adhesive interface is suppressed, and the electrical resistance of the electrical contact surface of the terminal portion at the contact interface is prevented from increasing. It plays a role and the protrusion width is usually set to 0.15 to 0.6 times the width of the electro-adhesive tape body.

In the electroconductive adhesive tape according to the present invention, the separate tape is usually handled in a state where the separate tape is temporarily attached, and the separate tape is peeled off during use. Further, the tape base material surface of the auxiliary tape is subjected to a peeling treatment (for example, a silicone-based or long-chain alkyl-based peeling treatment),
It can also be handled in a wound state.

The conductive adhesive tape according to the present invention is used for electrical continuity, especially grounding, in various circuit parts of various electronic devices. FIG. 4B shows a cross-sectional view taken along line 4B-B in FIG. In (a) of FIG. 4 and (b) of FIG. 4, 4 is an adherend, which includes electrode portions 41, 41 and an insulating portion 42. Reference numeral A denotes a conductive adhesive tape according to the present invention, in which the width-side protruding portions 20 and 20 of the auxiliary tape 2 and the conductive tape base material 11 of the conductive adhesive tape body 1 are pressure-sensitive. The electrodes are adhered to the adherend 4 by the adhesive layers 22 and 12, and are electrically connected by the conductive portion 110 between the electrode 41 and the conductive tape base material 11 and the conductive tape base material 1 in the longitudinal direction. 41 and 41 are electrically connected,
In addition, the seal is reinforced by the pressure sensitive adhesive layer 22 bonding between the protruding portions 20 at both ends of the width of the auxiliary tape 2 and the adherend 4. Both ends of the conductive adhesive tape A can be sealed with a normal pressure-sensitive adhesive tape [shown by a dotted line 5 in FIG. 4A).

In the conductive adhesive tape according to the present invention, the tape base material or the pressure-sensitive material of the auxiliary tape is used so that the identification can be easily performed even when the proximity adhesion or the cross adhesion is performed. It is preferable to color the adhesive layer. Further, the shape of the conductive adhesive tape can be changed according to the shape of the attachment site, and for example, it can be branched so that multiple points are grounded by a common conductive adhesive tape, In this case, the identification based on the shape and the color can be used together.

In the conductive adhesive tape according to the present invention, when the outer surface is pressed in the adhered state, for example, as shown in FIG. It is inserted in the gap between the
In the case of pressing with a cover, a tape base material 21 of the auxiliary tape 2 having a cushioning property is used, and the pressure generated by the compression of the cushion is applied to the pressure sensitive adhesive layers 12, 22.
Can be made to act on the adhesive interface of or the electrical contact interface of the terminal portion 111.

[0014]

The cross-sectional area (average value) of the body portion of the conductive portion 110 is S ₁ , the elastic modulus is E ₁ , and the conductive adhesive tape for one conductive portion is used.
Supposing the plane area of the pressure-sensitive adhesive layer 12 of the main body 1 to be S ₂ and the elastic modulus of the pressure-sensitive adhesive layer 12 to be E ₂ , the compressive stress generated in the body of the conducting portion 110 against the pressure applied for attachment. F ₁ ,
If the compressive stress generated in the pressure-sensitive adhesive layer 12 is f ₂ , then f ₁ / E ₁ = f ₂ / E ₂ holds, and the pressing force F is F = f ₁ S ₁ + f ₂ S ₂ , The compressive stress f ₂ of the pressure-sensitive adhesive layer 12 of the conductive adhesive tape body 1 is given by f ₂ = F · E ₂ / (E ₁ S ₁ + E ₂ S ₂ ). Therefore, S ₁ = 0, that is, the compressive stress f ₂ of the pressure-sensitive adhesive layer 12 of the conductive adhesive tape body 1 becomes smaller than that in the case where the conductive tape base material 11 has no conductive portion. Pressure-sensitive adhesive layer 1 for conductive tape substrate 11
The adhesive force to the adherend 4 per unit area of 2 becomes low. In addition, it is necessary to widen the plane area of the terminal portion 111 of the conductive portion 110 to some extent to secure a sufficient electrical contact area between the terminal portion 111 and the adherend 4, and in this case, relatively pressure-sensitive adhesion is required. The contact area of the agent layer 12 with the adherend 4 is reduced. Therefore, in the case of only the conductive adhesive tape main body 1, since the adhesive force of the pressure-sensitive adhesive layer 12 is low and the adhesive area is small, the conductive tape base material 11 and the adherend 4 are adhered. In the high humidity atmosphere, the adhesive interface with and has a low sealing property, and in a humid atmosphere, moisture / water penetrates into the contact interface between the terminal portion 111 of the conducting part 110 and the adherend 4, and the contact interface is oxidized to cause electrical discharge. The resistance increases.

However, in the present invention, the tape base material 2 is used.
An auxiliary tape 2 having a pressure-sensitive adhesive layer 22 on one side thereof is protruded from both ends of the width of the conductive adhesive tape body 1 and is bonded on the pressure-sensitive adhesive layer 22. In order to bond the protrusions 20 at both ends of the width of the tape 2 to the adherend 4, the seal portion is made longer by increasing the seal distance to the adhesive interface between the conductive tape base 1 and the adherend 4. It is possible to suppress the ingress of moisture and water into the contact interface between the terminal 111 part and the adherend 4, and it is possible to prevent an increase in the electrical resistance at the contact interface. This action / effect can be confirmed by comparing the resistance measurement tests of the example and the comparative example described below.

[0016]

【Example】

[Example 1] Thickness 50μ specified in JIS H 4160 1N30
m soft aluminum foil on one side with a thickness of 50 μm acrylic pressure-sensitive adhesive layer (elastic modulus at 20 ° C. 1 kg / cm
² ) is applied, and the distances a and b in (a) of Fig. 1 are 5m.
m, an outer diameter of the punch is 0.425 mm, an inner diameter of the die is 0.5 mm, and a press is used to form a conducting portion having a shape shown in (b) of FIG. 1
Cut to 2 mm to make a conductive adhesive tape body, thickness 50
A polyester film having a thickness of μm and a base material having a thickness of 50 μm coated with an acrylic pressure-sensitive adhesive layer having a thickness of 50 μm, and an auxiliary tape having a width of 20 mm, which is attached to the main body of the conductive adhesive tape, have conductivity. An adhesive tape was obtained.

[Example 2] Other conditions (conductive adhesive tape body, width of auxiliary tape) were used except that a polyethylene foam base material having a thickness of 3 mm was used as the tape base material of the auxiliary tape. The pressure-sensitive adhesive layer of the auxiliary tape, etc.) was the same as in Example 1.

Example 3 A 40 μm thick natural rubber pressure-sensitive adhesive layer (elastic modulus of 0.5 kg at 20 ° C.) is provided on one side of a 35 μm thick tough pitch copper foil specified in JIS H 2101.
/ Cm ² ), and the intervals a and b in FIG.
Is 5 mm, the conical male die 31 in FIG. 3A has a height of 150 μm, and the internal angle is 20 degrees. Using a drawing die and a press, the conducting portion 110 having the shape shown in FIG. It is formed and cut into a width of 12 mm to form a conductive adhesive tape body, and a natural rubber pressure-sensitive adhesive layer having a thickness of 50 μm and a thickness of 40 μm is formed on one surface of a tape base material of a yellow colored polyester film. The coated auxiliary tape having a width of 20 mm was attached to the conductive adhesive tape body as above to obtain a conductive adhesive tape.

[Comparative Example 1] Compared with Example 1, the width of the auxiliary tape and the width of the conductive adhesive tape are made equal to each other, and both ends of the width of the auxiliary tape and the main body of the conductive adhesive tape are compared. Same as Example 1 except that both ends of the width match. [Comparative Example 2] Compared with Example 3, the width of the auxiliary tape and the width of the conductive adhesive tape are made equal to each other, and the width ends of the auxiliary tape and the width ends of the conductive adhesive tape body are made equal to each other. Same as Example 3 except that

Regarding the example product and the comparative example product,
A resistance value test was conducted under the following conditions. [Test conditions] Two copper foils are placed on the insulating film strip with a space between them, and the conductive adhesive tape of the sample is attached across these copper foils. The measurement of the resistance value is performed by contacting the blades with each other at an initial stage and after standing for 168 hours in a high temperature / high humidity tank having a temperature of 60 ° C. and a relative humidity of 90%.

When this test was conducted for each of the example products and the comparative example products, the initial resistance value was as follows.
No difference was observed between the example product and the comparative example product. Regarding the resistance value after being left for 168 hours in the high temperature and high humidity tank, no substantial difference from the initial resistance value was observed in any of the example products, but in the comparative example product, the initial resistance value An increase of 100 to 200 times was observed.

[0022]

According to the present invention, a pressure-sensitive adhesive layer is provided on one surface of a conductive tape base material, the base material penetrates the adhesive layer, and has a terminal portion at its tip. This tape is attached to a conductive adhesive tape provided with conducting portions at desired intervals.
By simply sticking a pressure-sensitive adhesive auxiliary tape having a width wider than that of the adhesive band, it is possible to guarantee the conduction stability under high temperature and high humidity and provide a highly reliable conductive adhesive tape. Further, since the traces of the draw forming on the surface of the conductive tape base material are covered with the auxiliary tape, it is possible to reliably eliminate the cuts on the fingers when the hand is stuck, which is safe.

[Brief description of drawings]

1 (a) is an explanatory view showing an example of a conductive adhesive tape according to the present invention, and FIG. 1 (b) is a sectional view taken along the line of (i) in FIG.

FIG. 2 is an explanatory view showing a procedure for forming a conductive portion of the conductive adhesive tape shown in FIG.

3 (a) and 3 (b) are explanatory views showing a mold for molding a conductive portion different from the above of the conductive adhesive tape according to the present invention, and FIG. 3 (c). [Fig. 3] is an explanatory view showing a conducting portion formed by the mold.

4 (a) is an explanatory view showing a use state of the conductive adhesive tape according to the present invention, and FIG. 4 (b) is FIG. 4 (a).
FIG.

FIG. 5 is an explanatory view showing a usage state of the conductive adhesive tape according to the present invention which is different from the above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conductive adhesive tape main body 11 Conductive tape base material 12 Pressure sensitive adhesive layer 110 Conductive part 111 Terminal part 2 Auxiliary tape 21 Tape base material 22 Pressure sensitive adhesive layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C09J 7/02 JLH H05K 3/32 B 8718-4E (72) Inventor Naoki Matsuoka Ibaraki City, Osaka Prefecture Hozumi 1-2, Nitto Denko Corporation

Claims (2)

[Claims] 1. A pressure-sensitive adhesive layer is provided on one surface of a conductive tape base material, the conductive tape base material is penetrated through the adhesive layer, and a terminal portion is provided at a tip thereof. An auxiliary tape having a pressure-sensitive adhesive layer on one surface of the tape base material is provided on the other surface of the base material of the conductive adhesive tape main body provided with conductive portions at intervals. -A conductive adhesive tape characterized in that it is protruded from both ends of the width of the tape body and is adhered to the pressure-sensitive adhesive layer. 2. The conductive adhesive tape according to claim 1, wherein the tape base material of the auxiliary tape has a cushioning property.