JPH1197882A - Functional material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a functional material, wherein all of industrial characteristics (cost and mass-productivity), performance (electromagnetic wave shielding characteristic), and usability (applicability to objects) are satisfied. SOLUTION: This functional material has a structure, in which a bare copper wire 2 is bonded to at least one surface of a thin-layer base material 1 with an adhesive layer (ad) in a network or in parallel. Preferably, the diameter of the bare copper line 2 is 100 μm or less, while the interval between the bare copper lines 2 (maximum interval for network, or an interval between adjoining lines for parallel lines) is set within a range of 4±3 mm. The adhesive layer (ad) is preferably a layer of pressure-sensitive additive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a functional material having a required electromagnetic wave shielding property while having a simple structure.

[0002]

2. Description of the Related Art Recently, much attention has been paid to electromagnetic interference. There are several aspects to the electromagnetic wave problem.

[0003] The first point is whether or not electromagnetic waves generated from electronic / electrical devices directly affect the human body. At this point, the causal relationship is not always clear at this point,
Despite being verified and debated, it is not safe to say that it is safe to avoid exposing the human body to electromagnetic waves.

[0004] The second point is a problem of malfunction or noise due to electromagnetic waves generated when using electronic / electric equipment. Malfunction or noise may occur not only when an electromagnetic wave generated by a certain device affects peripheral devices due to electromagnetic interference, but also when an electromagnetic wave generated from a component of a certain device affects other parts of the same device. In any case, when the distance from the electromagnetic wave generation source is reduced, the risk of malfunction or noise increases.

[0005] With the spread of computers and personal communications,
In today's information-oriented society, it is indispensable to reduce obstacles caused by electromagnetic waves.
For example, as computers become more sophisticated, highly integrated, and everyday, the number of people who stay in the computer for a long time becomes enormous, and the malfunction of the computer impairs the reliability of the computer. Also, with the remarkable spread of mobile phones in recent years, the problem of electromagnetic interference with peripheral devices due to electromagnetic waves when using mobile phones has become a social problem.For example, sudden stoppage of drip pumps used in hospitals A malfunction in a person with a pacemaker implanted in the body may be due to nearby use of a mobile phone.

As a measure against electromagnetic wave shielding, conductive materials such as a metal plate, a metal foil, a metal deposition / sputtering layer, a metal plating layer, a metal sprayed layer, a conductive mesh / conductive fiber, a conductive coating film, and a conductive plastics. There is known a shield method that utilizes the ability of an electromagnetic wave to absorb or reflect electromagnetic waves.

[0007]

Among the measures for shielding electromagnetic waves, those aimed at reducing the weight include the use of metal foil, the installation of a metal deposition / sputtering layer, the use of conductive mesh and conductive fibers, and the like.

A typical metal foil is a tape having a layer structure of a metal foil / adhesive layer / peelable sheet. As the metal foil, a copper foil or an aluminum foil is used, and the metal foil is embossed. Can be applied. As the pressure-sensitive adhesive layer, there are a case where a conductive material is used and a case where a non-conductive material is used. In some cases, a metal foil is attached to an insulating film, and a conductive adhesive layer is further provided.

The metal deposition / sputtering layer is obtained by subjecting a plastic film to metal deposition or metal sputtering. If a transparent metal such as ITO is used,
Transparency can be obtained. Even if it is not a transparent metal, transparency can be obtained if the metal vapor deposition / sputtering layer is made porous by etching.

The conductive mesh / conductive fibers are formed by knitting conductive fibers, and the size of the eyes can be adjusted to obtain transparency.

However, various methods as described above in consideration of weight reduction and transparency are also applicable to (a) raw material cost, manufacturing cost, industrial efficiency including mass production, (b) electromagnetic shielding performance,
(c) There is a limit that it does not satisfy all three points of usability when applied to an object.

Under such a background, the present invention provides a functional material that satisfies all of industrial properties (cost and mass productivity), performance (electromagnetic shielding properties) and usability (applicability to an object). The purpose is to do so.

[0013]

Means for Solving the Problems The functional material of the present invention comprises:
It has a structure in which a bare copper wire (2) is stuck on at least one surface of a thin-layer base material (1) by an adhesive layer (ad) in a net shape or a parallel line shape.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

<Thin layer substrate (1)> As the thin layer substrate (1),
Flexible thin layers such as polymer films (including sheets), papers, fabrics (woven fabrics, knitted fabrics, and non-woven fabrics), leather, and the like can be given. The thin-layer base material (1) can also be made flame-retardant. The thin layer substrate (1) may be in the form of a wide sheet or a tape.

Of these, polymer films include polyolefin, polyester, polyamide, polystyrene,
Polyvinyl chloride, polyvinylidene chloride, fluororesin,
Polycarbonate, vinyl alcohol polymer, heat resistant resin (polyimide, polysulfone, polyethersulfone, modified polyphenylene ether, polyetheretherketone, polyetherimide, polyphenylenesulfide, poly-4-methylpentene-1, polyparaxylene, etc.) And a film made of a cellulose-based polymer, an elastomer or a rubber, and may be stretched in a uniaxial or biaxial direction.

The thin-layer substrate (1) may have not only a single-layer structure but also a multi-layer structure. Examples of multilayers are polymer film / polymer film, paper / polymer film, paper / paper, fabric / polymer film, fabric / paper, and the like.

<Installation method of bare copper wire (2)> In the present invention, the bare copper wire (2) is meshed or parallel-lined on at least one surface of the thin-layer base material (1) by an adhesive layer (ad). Stick it on

Regarding the method of installing the bare copper wire (2), a method of providing an adhesive layer (ad) on the thin-layer base material (1) and then attaching the bare copper wire (2) is preferably employed. However, in some cases, an adhesive layer (ad) is provided on the release surface of the release sheet (3), a bare copper wire (2) is adhered from above, and then the bare copper wire (2) installation side A method can also be adopted in which the surface is overlaid on the thin substrate (1).

<Bare Copper Wire (2)> The bare copper wire (2) may be a normal single wire, a bundled wire, a stranded wire, a flat foil wire, or the like. Note that metal wires other than copper wires are too expensive in the case of silver wires, and in the case of other metal wires, electromagnetic wave shielding properties are insufficient compared to copper wires, so they are not suitable for the purpose of the present invention. .

The diameter of the bare copper wire (2) is not particularly limited and can be selected from a wide range.
m or less, and in consideration of handleability, material cost, etc., 100 μm or less, 90 μm or less, 80 μm or less.
It is advantageous to make it as thin as μm or less. The lower limit can be up to several μm, but considering wire drawing cost and the like, it is advantageous that the thickness is somewhat thicker, such as 30 μm or more and 40 μm or more.

<Adhesion and installation of bare copper wire (2)> As described above, the bare copper wire (2) is attached to at least one surface of the thin-layer base material (1) by the adhesive layer (ad). It is stuck in a net or parallel line. Figures 1 and 2 show the case where bare copper wire (2) is attached
FIG. 3 is an explanatory view showing a case where the bare copper wire (2) is stuck and installed in parallel lines. In each case, the adhesive layer (ad) is not shown.

(Mesh-like Sticking Installation / Part 1) One case in the case of a mesh-like case is a case where a mesh in which a bare copper wire (2) is woven is used. Examples of this case include those having a square eye (see FIG. 1A), those having a hexagonal eye (see FIG. 2B), and a triangular eye (not shown). And the like.

In this case, a bare copper wire (2) that has been previously knitted or woven is prepared, and it is sheeted (thin-layer base material).
(1) In some cases, it may be attached to a release sheet (3)) via an adhesive layer (ad).

(Mesh-like Sticking Installation / No. 2) Another case in the case of a mesh-like case is a case using a net formed by simply layering parallel lines of bare copper wires (2) in different directions. In this case, there are ones in which parallel lines are superposed at right angles (see FIG. 2A), and those in which parallel lines are obliquely superposed (see FIG. 2B).

In order to stick and install a bare copper wire (2) on a sheet (thin base material (1) and optionally release sheet (3)) via an adhesive layer (ad), For example, a method as exemplified below can be adopted. In addition, various methods other than these methods can be adopted.

One of them is to first form an adhesive layer (ad) on a sheet.
After attaching the bare copper wire (2) as a parallel wire, the running sheet is deformed into a cylindrical shape, and the bare copper wire is
(2) is wound, and then the bare copper wire (2) is cut open at the seam of the cylinder with a cutter.

Another one is to first form an adhesive layer (ad) on a sheet.
After attaching the bare copper wire (2) as a parallel wire, the running sheet is spirally wound around a cylindrical guide, and the bare copper wire (2) is spirally wound in the opposite direction from above. Then, at the edge of the sheet where the spiral winding state is released, the bare copper wire (2) spirally wound later is cut with a cutter.

Another one is to apply an adhesive to the outer surface of the sheet while running the sheet, guide the sheet onto a drum, and guide the sheet from a bobbin through a vertically long jig arranged in the radial direction of the drum. Unwind the number of bare copper wires (2) and swing the jig in the width direction of the sheet.
Is stuck on the sheet in a 45 ° direction zigzag on the drum.

(Parallel-lined sticking installation) <Parallel-lined sticking installation of bare copper wire (2)> In the case of parallel lines, straight parallel lines (see FIG. 3A), wavy lines Parallel lines (see FIG. 3B), zigzag parallel lines (FIG. 4)
(See (c))), and is usually a straight parallel line. FIG. 3 (d) shows a case where straight parallel lines are adhered to the one surface and the opposite surface of the thin-layer base material (1) in different directions. When parallel lines are used, the electromagnetic wave shielding properties are lower than when they are meshed.However, depending on the application, lighter electromagnetic wave shielding properties may be required in some applications. Yes, it is worth it.

To install the bare copper wire (2) as a parallel line on the sheet (thin base material (1), and optionally release sheet (3)) by means of an adhesive layer (ad), for example, run the sheet While applying the adhesive, the adhesive is applied to the outer surface by the applicator and guided onto the drum, and the bare copper wire (2) drawn out from the bobbin aligned in the axial direction of the drum may be adhered on the drum . If the supply of the bare copper wire (2) onto the drum is performed while oscillating, a wavy or zigzag wire can be obtained.

<Spacing between Bare Copper Wires (2)> The spacing between the bare copper wires (2) adhered and installed (maximum spacing in the case of a mesh, spacing between adjacent wires in the case of a parallel wire) is required. It is selected from a wide range such as an interval of less than 1 mm to an interval of about 10 mm or more depending on the electromagnetic wave shielding property to be used.
It is practical to set the range to ± 3 mm, and more specifically to 4 ± 2 mm. In this range, the material cost of the bare copper wire (2), the electromagnetic wave shielding properties, and the operability (usability) to apply to the object are all most effectively satisfied, and furthermore, the transparency can be improved. .

<Adhesive Layer (ad)> As the adhesive for forming the adhesive layer (ad), a pressure-sensitive adhesive (that is, a pressure-sensitive adhesive), a heat-sensitive adhesive, a rewetting adhesive, a solvent-based adhesive or a water-based adhesive can be used. Adhesives, solvent-free adhesives, UV-curable adhesives, and self-adhesives can be used, and particularly, pressure-sensitive adhesives such as acrylic pressure-sensitive adhesives and rubber-based pressure-sensitive adhesives The agent is important.

In the present invention, since the bare copper wire (2) also serves as a conductive material, it is not usually necessary to make the adhesive layer (ad) conductive. powder,
A conductive adhesive layer (ad) may be mixed with a conductive material such as short metal fiber, carbon black, and ionic polymer.

<Rolling etc.> In a typical embodiment of the functional material of the present invention, an adhesive layer (ad) is provided on at least one surface of the thin-layer substrate (1), and the adhesive layer (ad) is provided on the adhesive layer (ad). This is the case where the adhered net-like or parallel-lined bare copper wire (2) is partially exposed (exposed) from the adhesive layer (ad). In this embodiment, even if the functional material is rolled, the adhesive layer (ad) is applied to the back surface of the thin-layer base material (1) by the bare copper wire (2) protruding from the head.
Since the sticking of the functional material can be prevented, the functional material can be rolled and smoothly fed out. In addition, even if it cut | disconnects to a predetermined | prescribed dimension without making it roll-wound, it can be piled up.

<Coating or Backside Treatment of Release Sheet (3)>
However, if necessary (such as when the distance between the attached bare copper wires (2) is large), bare copper wires on the adhesive layer (ad)
On (2), a release sheet (3) having at least one surface having a release property can be covered. As the release sheet (3) at this time, for example, a polymer film or paper having one surface treated with a release agent such as a silicone compound, a plastic film formed by internally adding a release material, and a sheet For example, a plastic film made of a polymer having releasability is used.

When the adhesive layers (ad) are disposed on both sides of the thin-layer base material (1), the release sheets are provided on both adhesive layers (ad).
(3) or a release sheet (3) having release properties on both sides on one side of the adhesive layer (ad).

Further, the surface of the thin layer substrate (1) opposite to the side where the adhesive layer (ad) is provided may be subjected to a back surface treatment for releasing, so that the whole can be rolled. Examples of the back surface treatment agent include a silicone compound, a polymer having a long-chain alkyl group, and polyethyleneimine.

<Use> The functional material of the present invention having the above structure has a preferable electromagnetic wave shielding property, and is therefore particularly useful as an electromagnetic wave shielding material. This electromagnetic wave shielding material is used for a wide range of applications to prevent leakage or intrusion of electromagnetic waves, for example, a material for covering the whole or built-in parts or gaps of electronic / electric equipment, a sheet wound around a cable, a sheet adhered to a mobile phone, a mobile phone. Bags for storing, packaging bags for storing electronic components, materials to be stuck to glass, sheets to be stuck to viewing windows of instruments, etc., walls and ceiling materials for electromagnetic wave prevention rooms, and electromagnetic waves from displays of electronic and electric devices Can be used as a sheet for attaching a transparent plate to prevent the occurrence of an electromagnetic wave, or an apron for preventing electromagnetic waves. Since this functional material also has an antistatic property, it can be used as an electromagnetic shielding material having an antistatic property.

[0040]

The present invention will be further described with reference to the following examples. 4 to 6, the adhesive layer (ad) is indicated by dotted points.

<Production of Functional Material> Example 1 FIG. 4 is a perspective view showing an example of the functional material of the present invention.

A bare copper wire (2) having a diameter of 60 μm was plain-woven to produce a grid-like net. The size of the eyes was 3 mm x 3 mm. An adhesive layer (ad) having a thickness of about 30 μm is obtained by applying an acrylic pressure-sensitive adhesive to a 40 μm-thick polyester film (biaxially stretched polyethylene terephthalate film) as an example of the thin-layer substrate (1) and then drying. Then, the grid-like net prepared as described above was adhered from above. As a result, a functional material having a layer configuration of (1) / (ad) / (2) was obtained.

In this functional material, an adhesive layer (ad)
A bare copper wire (2) protruding from the
Even if the back surface of (1) is not subjected to a back surface treatment for release or a release sheet (3) is covered so as to cover the adhesive layer (ad), it is rolled as shown in FIG. And can be smoothly fed out.

Embodiment 2 FIG. 5 is a perspective view showing another example of the functional material of the present invention.

A thickness of 30 μm as an example of the thin layer substrate (1)
An acrylic pressure-sensitive adhesive is applied to the polyester film and dried to form an adhesive layer (a) having a thickness of about 30 μm.
d) and then a bare copper wire with a diameter of 60 μm (2)
Is attached to a straight parallel line at a predetermined interval (for example, 1 mm interval, 3 mm interval, 5 mm interval, etc.), and then the same bare copper wire (2) is placed on it at the same interval in the direction perpendicular to the above. (The vertical and horizontal bare copper wires (2) are in direct contact with each other). Thereby, the functional material of FIG. 5 having the layer configuration of (1) / (ad) / (2) / (2) was obtained.

This functional material can be roll-wound as it is in the same manner as in Embodiment 1, and can be smoothly fed out.

Embodiment 3 FIG. 6 is a perspective view showing still another example of the functional material of the present invention.

A thickness of 30 μm as an example of the thin-layer substrate (1)
An acrylic pressure-sensitive adhesive is applied to the biaxially oriented polypropylene film of Example 1 and dried to form an adhesive layer (ad) having a thickness of about 30 μm, and then a bare copper wire (2) having a diameter of 60 μm is formed thereon. , And a release sheet (3) (release paper or polyester release sheet) was further laid on top of it. This gives (1) / (ad) / (2) /
The functional material of FIG. 6 having the layer configuration of (3) was obtained, and was roll-wound.

<Use as Electromagnetic Wave Shielding Material> The roll-wound functional materials of Examples 1 to 3 are fed out, and as it is (in the case of Example 3, the release sheet (3) is peeled off and removed). , Computer housings and gaps,
Cable terminals, necessary parts of the mobile phone housing,
(Electromagnetic wave shielding plate made of polymethyl methacrylate plate or polycarbonate plate placed on the front side of the display, instrument window, glass surface, etc.), it is possible to provide electromagnetic shielding to the target object while maintaining transparency. it can.

The electromagnetic wave shielding property at this time is a bare copper wire.
(2) The larger the eyes or the wider the lines, the lighter the light, the smaller the eyes or the narrower the lines, the higher the level, and the net-like arrangement has much higher electromagnetic wave shielding than the parallel-line arrangement. Since there is a tendency, the installation mode of the bare copper wire (2) may be selected according to the purpose.

[0051]

The functional material of the present invention has a structure in which a bare copper wire (2) is adhered to at least one surface of a thin-layer substrate (1) in a mesh or parallel line by an adhesive layer (ad). It has.

The bonding and installation of the bare copper wire (2) on the thin-layer base material (1) can be performed easily and continuously by using a simple machine / equipment. Can be used at a low cost and can be mass-produced at a low cost. In addition, the bare copper wire is separated from the adhesive layer (ad) provided on the thin-layer base material (1).
If a part of (2) is exposed, the roll of the functional material and the smooth feeding or stacking of the functional material can be performed without performing the release sheet (3) or the back surface release treatment.

Since the bare copper wire (2) is used, the electromagnetic wave shielding property is good. By selecting the mesh size and the interval between the wires, the electromagnetic wave shielding property can be changed from a light electromagnetic wave shielding property to a high electromagnetic wave shielding property. (For example, if the bare copper wire (2) is stuck on a mesh with a relatively small mesh size, the electromagnetic wave shielding effect is excellent in a wide range of frequencies of 3 GHz or less or 1 GHz or less). Is obtained). In addition, since the application to the target can be performed simply by sticking, the workability is good.

As described above, the functional material of the present invention satisfies all of the industrial properties (cost and mass productivity), the performance (electromagnetic shielding properties) and the usability (application to the object), and is extremely practical. It is expensive.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an example of a case where a bare copper wire (2) is stuck and installed in a net shape.

FIG. 2 is an explanatory view showing an example of a case where a bare copper wire (2) is stuck and installed in a net shape.

FIG. 3 is an explanatory diagram showing an example of a case where bare copper wires (2) are stuck and installed in parallel lines.

FIG. 4 is a perspective view showing an example of the functional material of the present invention.

FIG. 5 is a perspective view showing another example of the functional material of the present invention.

FIG. 6 is a perspective view showing still another example of the functional material of the present invention.

[Explanation of symbols]

 (1) ... thin layer substrate, (2) ... bare copper wire, (3) ... release sheet, (ad) ... adhesive layer

Claims (4)

[Claims] 1. A function characterized by having a structure in which a bare copper wire (2) is stuck in a net-like or parallel-line manner on at least one surface of a thin-layer substrate (1) by an adhesive layer (ad). Material. 2. The functional material according to claim 1, wherein the diameter of the bare copper wire (2) is 100 μm or less. 3. The functional material according to claim 1, wherein the distance between the bare copper wires (2) is in the range of 4 ± 3 mm (the maximum distance in the case of a mesh, and the distance between adjacent lines in the case of a parallel line). . 4. The functional material according to claim 1, wherein the adhesive layer (ad) is a layer of a pressure-sensitive adhesive.