JPS63227687A - Electrically conductive double-side adhesive tape - Google Patents

Abstract

PURPOSE:To obtain the titled tape outstanding in electrical conductivity, enabling good adhesive state to be retained for a long period, by partly providing pressure-sensitive adhesive layer with electrically conductive layer so as to be adhesive, even on the electrically conductive layer-provided surface, to adherend through the exposed area of the pressure-sensitive adhesive layer. CONSTITUTION:The objective tape can be obtained by partly providing one or both of the surfaces of a pressure-sensitive adhesive layer 1 in a double-sided adhesive tape with electrically conductive layer 2 so as to be adhesive to adherend through the exposed area of said layer 1 formed through numerous tiny holes provided on the electrically conductive layer 2, for example. The process to form the electrically conductive layer is e.g., application of a foil or film consisting of metal such as Al or Cu, Au on the pressure-sensitive adhesive layer, direct provision of the electrically conductive layer on the pressure-sensitive adhesive layer by a thin-film forming process such as sputtering, vacuum vapor deposition or ion plating.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a method in which a conductive layer is partially provided on the pressure-sensitive adhesive layer of a double-sided adhesive tape, and the exposed portion of the pressure-sensitive adhesive layer is also exposed on the surface on which the conductive layer is provided. The present invention relates to a conductive double-sided adhesive tape that can be bonded to an adherend through a conductive adhesive tape.

Conventional technologies and problems Electromagnetic shielding materials and potential maintenance materials for plastic containers that house electronic equipment such as computers, communication equipment, amplifiers, etc., and leakage current removal materials that also serve as grounding wires and fixing and vibration prevention for electrical components. Furthermore, it can be used as a material to prevent ignition caused by sparks based on static electricity such as triboelectricity, as an antistatic material for insulating materials, and as a weak heating element for preventing dew condensation and freezing. Conductive adhesive tape is used.

Conventionally, conductive adhesive tapes have been made by forming a large number of small conductive protrusions on one side of a conductive base material such as metal foil, and providing a pressure-sensitive adhesive layer to cover the small protrusions. It was known. According to this, when the tape is adhered to a conductor and energized, the pressure-sensitive adhesive at the tip of the small protrusion undergoes dielectric breakdown and a conductive state is formed. Changes in conductivity due to layer contraction or expansion are suppressed.

Therefore, the drawbacks of conventional conductive adhesive tapes in which conductive powder is mixed into the pressure-sensitive adhesive layer to impart conductivity are eliminated.

However, since dielectric breakdown of the pressure-sensitive adhesive at the tip of the small protrusion occurs, a constant positional relationship between the pressure-sensitive adhesive layer and the conductor at the tip is required in order to form a stable conductive state at all times. However, there was a problem in that it was necessary to press the conductive adhesive tape onto the conductor side from above the conductive base material. Therefore, if the surface of the conductor is poor in smoothness and has irregularities, there is a problem that a stable conductive state cannot be formed unless pressure is applied to each part, and the problem is that the conductivity and its stability are generally poor. There was a point.

Furthermore, in various uses of conductive adhesive tapes, it may be desirable to be able to use both sides of the adhesive tape for adhesion to an adherend, and it is also desirable that conductivity be allowed to flow through both sides. In some cases,

Means for Solving the Problems The present invention solves the above problems by providing a conductive layer partially on the pressure-sensitive adhesive layer and allowing bonding to occur through the exposed portion of the pressure-sensitive adhesive layer. A conductive product that overcomes the problems and can form a stable conductive state without constantly pressing the tape, and has excellent conductivity, adhesiveness, and stability against contraction and expansion of pressure-sensitive adhesives. The adhesive tape is a double-sided adhesive tape so that both sides of the adhesive tape can be used for adhesion to an adherend.

That is, the present invention provides a double-sided adhesive tape with a conductive layer partially provided on one or both sides of the pressure-sensitive adhesive layer, so that the conductive layer can be attached to the adherend through the exposed portion of the pressure-sensitive adhesive layer even on the surface where the conductive layer is provided. The present invention provides a conductive double-sided adhesive tape characterized by being able to adhere to.

Effect With the above structure, the conductive layer occupies the upper surface of the conductive layer application surface, and it is possible to adhere to the adherend through the exposed portion of the pressure-sensitive adhesive layer. can be brought into contact easily and reliably with sufficient contact pressure, and this state can be maintained for a long period of time.

Example FIG. 1 shows an example in which a conductive layer 2 was provided only on one side of the pressure-sensitive adhesive layer 1.

The pressure-sensitive adhesive layer 1 consists of a base material 12 with adhesive layers 11 attached on both sides. This base material 12 is provided as necessary to suppress contraction or expansion of the pressure-sensitive adhesive layer 1 and stabilize its conductivity, and is generally made of a thin sheet made of paper, cloth, plastic film, or the like. Ru.

There are no particular limitations on the adhesive used to form the pressure-sensitive adhesive layer 1, and known adhesives such as rubber adhesives, acrylic adhesives, silicone adhesives, etc. can be used.

The thickness of the pressure-sensitive adhesive layer 1 is generally 1 to 500 μm, but is not limited thereto, and is appropriately determined in relation to the thickness of the conductive layer.

The conductive layer 2 is partially applied to the pressure-sensitive adhesive layer. As a result, a part of the surface of the pressure-sensitive adhesive layer is exposed, and it becomes possible to adhere to an adherend through the exposed part. In the above embodiment, the conductive layer 2 was provided on only one side of the pressure-sensitive adhesive layer 1, but in the present invention, the conductive layer 2 may be provided on both sides of the pressure-sensitive adhesive layer 1. .

There is no particular limitation on the method of partially providing the conductive layer 2 on one or both sides of the pressure-sensitive adhesive layer 1.

Typical examples of the partially attached conductive layer 2 include:
The conductive layer 2 is provided in stripes in the length direction of the tape as shown in FIG. 2 or in the width direction of the tape as shown in FIG.
Alternatively, the conductive layer 2 in which H-shapes are arranged in series as shown in Figure 4.
Anisotropic conductive tape can be formed by providing an anisotropic conductive tape, or a conductive layer 2 having a diagonal grid pattern as shown in Figure 5, or a conductive layer 2 with many small holes as shown in Figure 6 so that there is no bias in the direction of conduction. Further, as shown in FIGS. 7 and 8, conductive layers 2 having a large number of small holes are provided in stripes in the width direction and length direction of the tape.

There is no particular limitation on the ratio of the total area of the exposed surface of the pressure-sensitive adhesive layer to the area occupied by the conductive layer on the surface on which the conductive layer is provided, and is appropriately determined depending on the purpose of use. The higher the proportion of the exposed surface of the pressure-sensitive adhesive layer, the better the adhesive force can be. Achieving high adhesive strength and high conductivity can be achieved by, for example, increasing the proportion of the exposed surface of the pressure-sensitive adhesive layer. Alternatively, this can be carried out by increasing the thickness of the conductive layer and sinking the conductive layer into the pressure-sensitive adhesive layer.

The method of forming the conductive layer 2 is Als CLIs Au.
sAgs Ni1Crs Ins A method of attaching a foil or film made of a usual metal such as Sn, PB, Pd, an alloy thereof, or an oxide thereof to the pressure-sensitive adhesive layer 1, a sputtering method, a vacuum evaporation method, etc. Pressure-sensitive adhesive layer 1 is formed using a thin film forming method such as
The most common method is to attach it directly to the

The appropriate thickness of the conductive layer 2 is 50 A to 10 um, preferably 100 A to 10 um. Its thickness is 50A
If it is less than that, the conductivity and long-term stability will be poor, which is not preferable. On the other hand, it is likely to be difficult to involve the exposed portion of the pressure-sensitive adhesive layer 1 exceeding 100 μm in adhesion.
Further, it becomes difficult to correct warpage of the conductive layer using adhesive strength and maintain a good state. Furthermore, when using the conductive double-sided adhesive tape, the cutting processability is poor, which may cause some inconvenience.

Note that 3 in FIG. 1 is a separator layer stuck on one side of the pressure-sensitive adhesive layer 1. This is provided as necessary to facilitate the handling of the conductive double-sided adhesive tape, and is made of a tape-like or sheet-like thin material such as paper or plastic, and in some cases has a peelable coating. It consists of a thin film body etc. Note that a material with good flexibility is preferably used for the separator layer.

When manufacturing the conductive double-sided adhesive tape of the present invention, when the thickness of the conductive layer provided on the pressure-sensitive adhesive layer is approximately 10 μm, the upper surface of the conductive layer and the exposed surface of the pressure-sensitive adhesive layer are The exposed surface of the pressure-sensitive adhesive layer may be elevated or the conductive layer may be lowered into the pressure-sensitive adhesive layer in advance so that the height difference between the conductive layer and the conductive layer is 10 μm or less, especially 5 μm or less. desirable.

The height difference between the top surface of the conductive layer and the exposed surface of the pressure-sensitive adhesive layer is 10
If it exceeds .mu.m, a large pressing force will be required to form a good adhesion state by adhering the surface on which the conductive layer is attached to an adherend, resulting in poor adhesion efficiency. Moreover, the adhesive state tends to change over time, and the stability of conductivity may be impaired.

Therefore, in order to maintain stable conductivity, a means for pressing the conductive layer-applied surface against the adherend may be necessary.

Note that it is generally undesirable to make the exposed surface of the pressure-sensitive adhesive protrude from the upper surface of the conductive layer because it tends to cause unstable conductivity when the conductive layer-attached surface is attached to an adherend.

Therefore, from the viewpoint of the efficiency of the adhesion work of the conductive double-sided adhesive tape or its conductive layer-applied surface, the ability to form good conductivity, and the maintainability of that state, it is necessary to Preferably, the upper surface of the conductive layer and the exposed surface of the pressure-sensitive adhesive layer are at the same level, or the exposed surface of the pressure-sensitive adhesive layer is slightly lower.

The conductive double-sided adhesive tape of the present invention can be used not only as the above-mentioned electromagnetic shielding material or weak heating element, but also as various sensors, for example.

That is, by deforming or dissolving the pressure-sensitive adhesive layer, cracks occur in the conductive layer, which causes disconnection of the conductive layer, so that it can be used for various detection means. for example,
If the pressure-sensitive adhesive layer is formed of a material that is easily deformed or dissolved by organic solvents, it can be used as a solvent sensor, and it can also be used as a solvent sensor. If it is made of a material that is easy to use, it can be used as a sensor for water, oil, heat, light, or the like.

Example 1 Elastic modulus at 20°C is 0, 9 k+r/cn?
1 mm wide on one side of the acrylic pressure sensitive adhesive layer (thickness 30 um).

Copper foil with a thickness of 0.1 μm was laminated at regular intervals using a roll laminator to obtain a conductive double-sided adhesive tape having a conductive layer in stripes in the length direction (see Figure 2).
. In this double-sided adhesive tape, the upper surface of the conductive layer on the surface on which the conductive layer is attached is at the same level as the exposed surface of the pressure-sensitive adhesive layer (
The height difference was ○) or slightly higher (step difference 0.1 um).

Example 2 A conductive double-sided adhesive tape was obtained according to Example 1, except that the thickness of the copper foil forming the conductive layer was 1 μm.

In this double-sided adhesive tape, the upper surface of the conductive layer on the surface on which the conductive layer is attached is at most 1 μm higher than the exposed surface of the pressure-sensitive adhesive layer.
It was expensive.

Example 3 According to Example 1, a conductive layer was provided in the width direction to obtain a horizontal stripe type conductive double-sided adhesive tape (see FIG. 3). In this double-sided adhesive tape, the upper surface of the conductive layer and the exposed surface of the pressure-sensitive adhesive layer on the surface on which the conductive layer was attached were almost at the same level.

Example 4 According to Example 1, a diagonal lattice type conductive double-sided adhesive tape consisting of a conductive layer having a unit width of 1 m was obtained (see FIG. 5).

In this double-sided adhesive tape, the upper surface of the conductive layer and the exposed surface of the pressure-sensitive adhesive layer on the surface on which the conductive layer was attached were almost at the same level.

Example 5 On the entire surface of one side of an acrylic pressure-sensitive adhesive layer (thickness: 3 hm) with an elastic modulus of 0 and 9 kg/cd at 20°C, 4 to 5 holes were placed in the width direction of the tape with a hole spacing of 1 mIn.
6 rows/10 mm of holes with diameter lInlTl at a ratio of 10 cylinders
(Longitudinal direction) Laminate the provided conductive layer forming member made of copper foil with a thickness of 0.1 μm using a roll laminator,
A conductive double-sided adhesive tape was obtained (see Figure 6). In this double-sided adhesive tape, the upper surface of the conductive layer on the surface on which the conductive layer is attached is at the same level (level difference O) as the exposed surface of the pressure-sensitive adhesive layer in the small hole, or slightly higher (level difference 0.1 um).
) was a thing.

Example 6 A conductive double-sided adhesive tape was obtained according to Example 5, except that the thickness of the copper foil forming the conductive layer was lum.

In this double-sided adhesive tape, the upper surface of the conductive layer on the surface on which the conductive layer is attached is at most 1 μm higher than the exposed surface of the pressure-sensitive adhesive layer.
It was expensive.

Example 7 Hole spacing is 1+nm, 3 to 3.52 in width direction of tape
3.52 rows/1 hole of 2 diameters at the ratio of pcs/1 OIWl
A conductive double-sided adhesive tape was obtained in accordance with Example 5, except that a copper foil with a thickness of 0.1 um and a thickness of 0 mm (in the length direction) was used.

In this double-sided adhesive tape, the upper surface of the exposed surface of the pressure-sensitive adhesive layer on the surface on which the conductive layer was attached was at the same level as the upper surface of the conductive layer in almost all the small holes.

= 12 - Evaluation test [resistance J carried out on two parallel gold electrodes with a spacing of 10 mm, the conductive double-sided adhesive tape obtained in the example was applied through its conductive layer to approximately 2 k
The electrical resistance was measured using a multimeter (manufactured by Takeda Riken Co., Ltd.) after being pressed and bonded with a rubber roll (g) and left at 20° C. for 20 minutes.

[Adhesive strength] ゛ A thickness of 25 mm on the pressure-sensitive adhesive surface without a conductive layer attached.
A pm polyester film was attached to make an adhesive tape, and measurements were made using this in accordance with ASTM D 1000. Note that the adhesive strength of the pressure-sensitive adhesive surface without the conductive layer was 1900 (g/10+nm).

The results are shown in the table.

Effects of the Invention Since the surface on which the conductive layer is attached in the conductive double-sided adhesive tape of the present invention is divided into the conductive layer' and the exposed surface of the pressure-sensitive adhesive layer,
It is possible to adhere to an adherend in good condition through the exposed surface of the pressure-sensitive adhesive layer.

As a result, the conductive layer reliably and in good contact with the adherend has low contact resistance and excellent conductivity, and this good contact state is maintained over a long period of time, resulting in highly stable conductivity. Lasts for a long time.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the embodiment, and FIGS. 2, 3, 4, 5, 6, 7, and 8 are plan views illustrating other forms of attaching the conductive layer. It is a diagram. 1: Pressure sensitive adhesive layer 2: Conductive layer

Claims (1)

[Scope of Claims] 1. A conductive layer is partially provided on one or both sides of the pressure-sensitive adhesive layer in the double-sided adhesive tape, and the surface on which the conductive layer is provided is also coated through the exposed portion of the pressure-sensitive adhesive layer. A conductive double-sided adhesive tape characterized by being able to adhere to objects. 2. The conductive double-sided adhesive tape according to claim 1, wherein the exposed surface of the pressure-sensitive adhesive layer is formed through a large number of small holes provided in the conductive layer. 3. The conductive double-sided adhesive tape according to claim 1, wherein the conductive layer is arranged with gaps to form the exposed surface of the pressure-sensitive adhesive layer. 4. The conductive double-sided adhesive tape according to claim 1, wherein the conductive layer is formed of a metal foil or metal oxide foil with a thickness of 50 Å to 100 μm. 5. The top surface of the conductive layer is at the same level as or higher than the exposed surface of the pressure-sensitive adhesive layer, and the level difference is 10 μm.
The conductive double-sided adhesive tape according to claim 1, wherein the conductive double-sided adhesive tape has a diameter of m or less.