JPS6257298A - Material for shielding electromagnetic wave - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a translucent electromagnetic shielding base material that has excellent electromagnetic shielding properties, is lightweight, and can be mass-produced.

B. Summary of the Invention The present invention aims to create a material that is relatively low cost and can be used in any situation, by uniformly combining a metal powder with a resistivity of 8 μΩem or less with a fast-curing ink. This relates to an electromagnetic shielding material which is made by mixing and printing a grid or striped pattern on the surface of a translucent plate or film.

C. Conventional technology The development of electronic equipment in recent years, especially with the improvement of peripheral technologies such as various printed wiring boards and integrated circuits that form the basis of electronic equipment, has led to remarkable developments in the supply and demand relationship for consumer electronic equipment. There is.

It is a fact that in the situation described in Party B, the amount of consumer electronic devices that are used not only in business offices but also for home use or owned by individuals is increasing significantly. It is.

Problems that the invention aims to solveBy the way, as electronic devices develop like this,
It is naturally expected that the number of occurrences of various troubles will increase as a result of this.

The biggest cause of this is the influence of electromagnetic waves that can reach electronic devices such as 41 and 41, and due to 6o1, for example, in computer computers, there is misleading information and calculation errors, and in display devices such as V1'R, the colors and images are It is quite conceivable that inconveniences may arise in terms of

Theoretically, the method of defending against the intrusion of electromagnetic waves is to shield the source of electromagnetic waves with a conductive material (electromagnetic shielding material), or conversely, shield electronic devices that are thought to be affected. For example, 1' protection has already been considered, and various electronic devices are actually protected using this method.

However, with these conventional methods (electromagnetic shielding materials with a diameter of 1.5 μm are made of metal, for example, the material used in J5 is not only heavy, but also satisfies 1) in terms of mass production and processability. It was not something I could enjoy.

It is also possible to use metal substitutes such as those mentioned in Part 7 and conductive glass, but these electromagnetic shielding materials do not have translucency and their usage is extremely limited. However, from the point of view of point (2), the current situation is that no one has found anything satisfactory in rice.

Furthermore, conventionally commercially available paints for electromagnetic shielding are generally opaque and have an electrical resistance of 10
It is about 105 Ωcm.

Also, 5n02. used for transparent electrodes etc. , InO3, etc., also had a resistance of about 10 3 to 10 5 Ωem, and both had poor electromagnetic shielding properties.

EMeans for solving the problem We conducted various studies to solve the problems in the conventional technology and to obtain a translucent electromagnetic shielding material that is highly versatile and can be used whenever necessary. , reached an electromagnetic shielding material made by uniformly mixing metal powder with a resistivity of 8 μΩ C1n or less with oil-sand type ink and printing it on the surface of a translucent plate material or film in a grid or ring shape -5= There is a sin.

F action The synthetic resin for paints or synthetic 434 resin for adhesives used in the present invention can be selected from fatty acid modified alkyd resins, epoxy resins, phenol resins, polyurethane resins, acrylic resins, etc. Particularly favorable results can be expected when ultraviolet curable epoxy acrylate-1 is used.

The concentration of the synthetic resin used at this time does not need to be particularly regulated as long as it maintains a viscosity suitable for printing, and specifically, one in the range of approximately 30 to 100,000 cP is used.

As the conductive material powder, specifically, one selected from among aluminum, nickel, and brass is used, but it is better to use relatively fine particles for dispersion in the synthetic Vt4 resin and for the final product. It is preferable to use a shielding material having an average particle diameter of about 0.5 to 1.5 μm because it can ensure uniformity of the printed state of the shielding material.

The usage stars of this conductive material powder are approximately 30 to 500.
The range is p l+ r.

If the amount is outside this range, for example, a small amount (μm), the electromagnetic shielding effect will not be sufficiently exhibited, while if it is too large, it will not only make printing difficult, but also cause mechanical damage to the final product. It becomes J′ which impairs the strength.

For the material of the transparent film or plate (17), a material that matches the characteristics required in the usage situation is appropriately selected from among glass plates, polyester films, and other equivalent materials.

Transparent film or printing on plate-like objects is grid-like,
This can be done in stripes or in concentric circles as in a 7 Lennel lens.

When actually using the translucent electromagnetic shielding material produced according to the present invention, if the material is a film, it must be prepared with a hardening or non-hardening adhesive such as an adhesive, a water-soluble adhesive, or a heat-sensitive adhesive. One or two types of adhesives selected from
Two or more types of adhesive can be applied to one or both sides of a transparent plate, either over the entire surface or in a pattern, for one application.

Further, for printing, a commonly used printing method can be used, but other methods such as hot tapping or a coating method using a coater can also be used.

G Example Hereinafter, the structure and effects of the present invention will be explained by specifically showing 17 examples.

In addition, the sample for measuring electromagnetic shielding characteristics in the examples is as follows:
A disk with a diameter of 80 + nm is used between the plate electrodes.
Insert it into a toy-sochi shape and measure the surface resistivity.
By using the sample shown in FIG. 4 and using the method shown in FIG. 5, the resistance R (Ω) between the mesh-like potential measuring electrodes 4,
Inter-electrode distance (mm), electrode width W (++un) J:
The shaft surface resistivity Rs was calculated using the following formula.

R5-(W/1)xR(Ω/sq) The distance between the current-carrying electrodes was 60 m+1, and the distance between the electrodes for potential measurement was 4011IIn.

Example 1 88% by weight of solvent-free ultraviolet curable Evoquin acrylate and 5% by weight of phenylbenzophenone as a photosensitizer
, P-dimethylaminoamin, isoamyl flavourate 3% by weight,
It was obtained by blending 3% by weight of calcium carbonate as a thickener, 0.4% by weight of hydroquinone mono, methyl ether, and 0.6% by weight of magnesium stearate as an antioxidant.
Aluminum powder 9 with an average grain size PI of 1 μm is added to this resist.
0phr added, thickness 50 μm 1 size 200
The fourth layer was placed on a polyester film of IIIm x 300mm.
As shown in the sample for surface resistivity measurement in the figure, 1 + n + n
When printing in a lattice pattern at intervals, the line width of the lattice was set to 100 μm), and cured by irradiating with ultraviolet rays.

In the figure, 1 is a conductive mesh with a line thickness of 100 μm, 2 is an electrode formed by applying silver paint, 3 is a polyester film, and 4 is an electrode for potential measurement.

The surface resistivity of this material was 5Ω/sq, and when the amount of aluminum powder added was changed, the electromagnetic shielding characteristics measured at a frequency of 5M I-1z had the behavior shown in Figure 1. Ta.

Furthermore, when the amount of aluminum added was 50 phr and the frequency was changed, the behavior of the characteristics was as shown in FIG. 2.

The sample size for measuring surface resistivity is 8 x 70I.
III11 rectangular shape, and the electrode parts at both ends (8 x 511
11+1) is decorated with silver beinod17.

For measuring the electromagnetic wave attenuation, TR4110M (manufactured by Takeda Riken Kogyo) was used, and 'rR415 was used as the high frequency source.
1 was used.

Example 2 Aluminum powder 9 with an average particle size of 1 μm in Example 1
Instead of using 0 phr, brass (zinc content 40%) powder with an average particle size of 1 μm was added to a polyester film with a thickness of 50 μm and a size of 200 III 11 × 300 III 11 with a line thickness of 100 μm and about 1 mm.
It was printed to draw a grid of intervals.

The surface resistivity at this time was 30 Ω/sq1.The electromagnetic shielding characteristics when the amount of added brass powder was changed had the behavior as shown in FIG. 3.

(1) Effects of the Invention According to the present invention, it is possible to easily manufacture a translucent electromagnetic shielding material, which has not been manufactured in the past, and the following effects can be expected.

(1) When used as an outer box for the housing of a small device, it becomes possible to check what is inside.

(2) When used in the window of a room or building housing large equipment, the interior and exterior can be seen through the window.

(3) If there is no room housing a large device (7 is used as a window in a building), it is possible to let in light through the window, so it is possible to save on internal lighting.

[Brief explanation of the drawing]

Figures 1 to 3 show the effectiveness as a translucent electromagnetic shielding material. Fig. 5 is a plan view showing a surface resistivity measurement sample cut out from the sample 17, and Fig. 5 is a schematic diagram of an apparatus for explaining the measurement of surface resistivity. 1. Conductive mesh, 2. Silver paint applied 17. 3. Transparent film; 4. Surface resistivity t (travel electrode).

Claims (7)

[Claims] (1) An electromagnetic shielding material made by uniformly mixing metal powder with a conductivity of 8 μΩcm or less with a fast-curing ink and printing it on the surface of a translucent plate or film in a grid or striped pattern. (2) Metal powder with an average particle size of 0.5 to 10 μm
The material for electromagnetic shielding according to claim 1, wherein 0 to 500 phr is used. (3) The material for electromagnetic shielding according to claim 1, wherein the printed lines have a thickness of 50 to 150 μm, and the distance between the lines is in the range of 0.5 to 1.5 mm. (4) The electromagnetic shielding material according to claim 1, which uses powder of a metal selected from aluminum, nickel, and brass. (5) The material for electromagnetic shielding according to claim 1, which comprises using a transparent film or plate-like material selected from glass plates, polyester films, or other equivalent materials. (6) The material for electromagnetic shielding according to claim 1, which comprises using an ultraviolet curable epoxy acrylate resin as a base material for a fast-curing ink. (7) The material for electromagnetic shielding according to claim 1, which comprises concentric printing as one form of striped printing.