JPH08311631A - Easily joinable electromagnetic wave shielding material and its production - Google Patents

Abstract

PURPOSE: To obtain an electromagnetic wave shielding material which allows the easy joining treatment of joints, has an excellent electromagnetic wave shielding effect and is relatively inexpensive and to provide a production method thereof. CONSTITUTION: This electromagnetic wave shielding material is formed by forming thermally sprayed layers consisting of one or >=2 kinds of Zn, Al and Zn-Al alloy having a coating weight of 70 to 300g/m<2> on the surfaces of a base material by continuous thermal spraying, or further, penetrating a penetrative coating material having surface resistivity not exceeding 0.1ohm/cm<2> into these thermally sprayed layers from above. The coating weight accuracy of thermal spraying is specified to ±10% and the continuous thermal spraying is executed without generating dust on the outside at the time of the production thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave shield material which can be easily joined and a method of manufacturing the same, and more specifically,
The present invention relates to an electromagnetic wave shielding material suitable for construction of a structure as a building material and the like and a manufacturing method thereof, which has excellent electromagnetic wave shielding properties, can be easily joined to other shielding materials, and has excellent workability and workability. It is a thing.

[0002]

2. Description of the Related Art In recent years, various electronic devices such as personal computers, word processors, and televisions have made remarkable progress such as higher performance, lighter weight and smaller size, and electromagnetic noise has become a major social problem. . In the past, electronic device housings were made of sheet metal, so there was little electromagnetic interference, but due to factors such as mass productivity, design, and price, plastic housings have become widely used, and other electronic devices caused by electromagnetic noise The obstacles (noise, malfunction) have become serious. Recently, against the electromagnetic interference (EMI) caused by this electronic device housing, it is obligatory to take noise countermeasures by FCC regulations in the United States and VDE regulations in West Germany, and in Japan, some regulations have started under VCCI regulations. Currently, Cu, Ni plating, A for electronic equipment housing noise
Although a large number of case shield materials such as vapor deposition, conductive paints (Cu, Ni-based), and conductive plastics mixed with conductive fillers are used, there are advantages and disadvantages such as shielding performance, price, and workability.

On the other hand, in addition to the housing of the electronic device, a method of shielding the entire room with a shield material has been studied for the purpose of protecting the electronic device and protecting privacy, and is commercially available as an anechoic chamber or a shield room. For such a shield having a large area, a shield material for an electronic device housing is rarely used because of problems in price and workability. At present, a steel plate, a plated plate, a metal plate such as a Cu plate, and a conductive non-woven fabric thinly plated with Cu and Ni are used, but the workability and the price are insufficient, and an urgent improvement is required. Further, it has already been confirmed in the electronic equipment casing that the Zn sprayed film has a shielding effect which is not inferior to that of a metal plate, but there is a problem in the spraying work, and it cannot be easily applied to a building structure.

[0004]

As described above, the electromagnetic wave shield construction method for building structures has problems of shield material, workability and cost. An ideal shield material should have a good shielding effect, be easy to work with, and cheap. Since the thin metal plates currently used require sheet metal processing, they are inefficient and have a safety (injury) problem. A further major operational problem is the method of joining seams. The effect of the electromagnetic shielding of the actual structure depends on the performance of the shield material itself and the shielding property of the joint, but the latter is said to be important in practice. No matter how good the shield material is, if the treatment of the joint part is inappropriate, electromagnetic waves will leak and there is no meaning of shielding at all. The larger the structure, the more joints there are, and the shield method becomes a problem.

Usually, soldering and welding are performed for joining metal plates, but workability is very poor. Conductive paste, conductive tape, etc. are also used, but they are not suitable for large-scale structures because they have an insufficient shielding effect and are expensive. Moreover, although the shield effect is excellent for Zn thermal spraying, the thermal spraying work is usually inefficient because it is performed manually, and a large amount of dust is generated, so dust masks and environmental pollution countermeasures are necessary. When the building structure becomes large-sized, hermetically sealed, and works at high places, the thermal spraying work becomes more difficult, which further increases the cost, making it difficult to apply Zn thermal spraying to the actual structure. Therefore, an object of the present invention is to easily join joints, to provide an excellent electromagnetic wave shielding (shielding) effect to the joints, and to obtain an electromagnetic shield material that is relatively inexpensive and easy to join, as well as pollution-free. Another object of the present invention is to provide a method for producing an electromagnetic wave shield material which enables continuous formation of a sprayed layer with high efficiency and high accuracy.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the gist of the present invention is that Zn, Al, Zn-having a basis weight of 70 to 300 g / m ² is used.
A sprayed layer made of one or more kinds of Al alloys is formed on the surface of the substrate by continuous spraying, or a surface resistivity of 0.1 ohm / cm ² from the top of the sprayed layer.
Electromagnetic wave shielding material that is easy to join and is permeated with an amount of penetrable paint that does not exceed 70%, and a basis weight of 70-
After spraying 300 g / m ² of one or more of Zn, Al, and Zn-Al alloys continuously with a unit weight accuracy of ± 10% without generating dust to the outside, or after doing so. , The surface resistance value of the sprayed surface is 0.
It is a method for producing an electromagnetic wave shield material which is easy to bond by coating and permeating in an amount not exceeding 1 ohm / cm ² . In this case, it is effective that the substrate is paper, cloth, gypsum board, plywood, or particle board.

[0007]

The electromagnetic wave shielding material of the present invention has a basis weight of 70-
Since a sprayed layer consisting of one or more of 300 g / m ² of Zn, Al, and Zn-Al alloy is formed on the surface of the base material, the electromagnetic wave shielding effect by itself is excellent and the conventional problems The electrical continuity at the joint that was described above is very excellent. In this case, the joining principle is that (1) the sprayed surface presents an extremely fine uneven surface, so if the sprayed surfaces are joined together, the uneven surfaces will mesh closely and electrical conduction will be obtained, and (2 ) By using a material in which the sprayed layer is an aggregate of metal particles and the sprayed base material itself has fine pores, if an adhesive is applied and the sprayed surfaces are pressed together, excess adhesive will cause the sprayed layer and the base material to adhere. The reason for this is that the sprayed metal surfaces come into electrical contact with each other.

Further, according to the method for producing an electromagnetic wave shielding material of the present invention, Zn having a basis weight of 70-300 g / m ²
Since one or more of Al and Zn-Al alloys are continuously sprayed with a basis weight accuracy of ± 10% without generating dust to the outside, a non-polluting and highly efficient electromagnetic wave shielding material is manufactured. be able to. In this case, by continuously feeding the base material to be sprayed into the spraying chamber and connecting a dust collecting device having a strong suction force to the spraying chamber, it becomes possible to prevent the leakage of dust to the outside, and It enables continuous thermal spraying of the material.

[0009]

EXAMPLES The spray metal is not limited to Zn, but Zn, Al, Zn
The reason why one type or two or more types of -Al alloys are used is to utilize the shielding property, corrosion resistance, and lightness of Al. A
It is a well-known fact that the 1-plate has a good shield property and a better corrosion resistance in the atmosphere than Zn.
Since 1 is as light as 2.70, the Al spray material is a shield material which is light and has good corrosion resistance. However, since it easily oxidizes during thermal spraying, Z
Spraying efficiency is inferior to that of n. Zn-A in which Al is dissolved in Zn
The l-alloy is an alloy having both properties depending on the compounding ratio.
Further, when two energized metal wires of the same type are short-circuited and melted by an arc-type thermal spraying means described later and blown with high-pressure air, even if one of the metal wires is changed to a different kind of metal wire, it can be sprayed (mixed spraying). For example, Zn and Al, Zn and Zn-A
It is possible to perform combined thermal spraying of a 1-alloy, Al and Zn-Al alloy, and the like. That is, according to the present invention, Zn, Al alone thermal spraying, Zn
-Al alloy spraying, Zn-Al mixed spraying are included.

Next, the basis weight of the sprayed layer is 70 to 300 g / m 2.
² (preferably 100 or more to 170 g / m ² ) is set at less than 70 g / m ^{2 because the} electromagnetic wave shielding effect is small, and when it exceeds 300 g / m ² , the shielding effect is not improved much and a thick film is formed. Problems such as unbearable processing, heavy weight, and difficult handling occur. There is no proportional relationship between the coating weight of the sprayed layer and the shield performance, and 100 g
/ M ² or more, the shielding performance does not improve so much even if the basis weight is increased, and the shielding performance is sufficient if it is 100 to 170 g / m ² . The reason why the weight per unit area is excessive is to improve durability (life). Since these sprayed coatings are relatively susceptible to corrosion in the atmosphere, especially with respect to moisture and dew condensation, the thickness was increased to 300 g / m ² in consideration of the life and bending workability of the sprayed coating.

As will be described later, in the present invention, the thermal spraying is performed with the precision of the basis weight of the sprayed metal being ± 10%, and thus the precision of the basis weight is ± 10%.
The reason is to keep the sprayed coating uniform. A sprayed film is a film formed by melting a metal wire with electricity or gas and blowing it with high-pressure air, but the spraying conditions tend to fluctuate, the sprayed film thickness also changes accordingly, and sometimes a defective part occurs in the film and the shield effect remarkably decreases. In some cases, a limit of ± 10% is set. For example, at a target of 100 g / m ² , 90-
It becomes 110 g / m ² . It should be noted that it is difficult to manufacture such a uniform sprayed film manually, and a highly controlled spraying device is required.

Further, the electromagnetic wave shielding material obtained by the present invention requires good workability such as cutting and bending and jointability of seams depending on the method of use. Therefore, depending on the application, paper, cloth,
Any of a gypsum board plate, a plywood board, and a particle board was used as a thermal spray base material. Any kind of paper or cloth can be used, but natural pulp or cotton is suitable, and organic paper or cloth with poor heat resistance cannot be used because its strength deteriorates due to thermal spraying heat. Zn, Al, Z on paper and cloth
The shield material (invention) manufactured by spraying one or more kinds of n-Al alloys can be easily cut and bent with scissors and is easy to use without cutting hands like a metal plate.
Moreover, the reason why gypsum board, plywood or particle board was adopted as the thermal spraying base material was that, as a result of research, it was found that these materials can further simplify the shield construction method. That is, in the case of sprayed paper or cloth, it is necessary to attach them to a building structure with an adhesive, but if a wall material that has been sprayed in advance is used, the adhering work is omitted, leading to cost reduction. Only a small amount of seam joining work remains.

Further, in the present invention, after spraying on paper or cloth, in order to improve the rust preventive property, the penetrating paint can be applied immediately after spraying. The type of penetrating paint is not particularly limited, but one that does not corrode Zn, Al, Zn-Al alloy,
It is necessary to avoid the use of paints that will obviously produce a coating film on the sprayed surface after coating and drying. Further, since the solid pigment in the paint tends to become an insulator at the time of joining, a clear (transparent) paint containing no solid pigment is preferable. As a concrete paint,
Examples include clear lacquer, room temperature to medium temperature dry type diluted acrylic paint, epoxy paint, urethane paint and the like. High temperature baking type paints are not preferable because they easily damage the paper and cloth as the base material. The purpose of the penetrative paint is not for complete rust prevention but for temporary rust prevention, so the coating amount may be small. If the coating is thick enough to cover the sprayed surface with a coating, the coating will become an insulator and seam bonding will not be possible. As a guideline for the coating amount, spraying or a roller coater is applied so that the surface resistivity after drying does not exceed 0.1 ohm / cm ² .

With respect to the shield material of the present invention thus obtained, an example of a seam joining means which is one of the problems of the prior art will be described. That is, as described above, the joining method and repair of the seam are the key points in the electromagnetic wave shield construction method, and the complete electrical continuity of the seam is necessary for that. Conventional shield materials require expensive conductive paste mixed with metal powder,
As the shielding material of the present invention, a usual fusuma glue, a water-soluble adhesive, and an organic adhesive are sufficient. FIG. 1 shows a schematic cross-sectional view of a seam joining method for a shield material according to the present invention. A tape 1a made of the same shield material is attached to a seam 2 of a shield material 1 by an adhesive 4
Is a method of joining and joining the sprayed layers 3 together.

First, when the base material is paper or cloth, the joining principle is as follows: (1) Since the sprayed surfaces have very fine uneven surfaces, if the sprayed surfaces are joined together, the uneven surfaces will mesh closely and the (2) The thermal spray layer is an aggregate of metal particles and the thermal spray base material itself is paper or cloth with fine pores, so if you apply adhesive and crimp the thermal spray surface, The adhesive penetrates or penetrates the sprayed layer and the base material, and the sprayed metal surfaces are electrically connected to each other. The principle is the same for the seam joining method of the shield material sprayed on the gypsum board plate, plywood or particle plate, and the sprayed paper or cloth is cut into a tape at the seam and attached with an adhesive.

Next, a method of manufacturing the electromagnetic wave shielding material of the present invention will be described. First, in the present invention, as described above, Zn, A having a basis weight of 70 to 300 g / m ² is applied to the surface of the base material.
l, Zn-Al alloy, one or more of them are continuously sprayed with a basis weight accuracy of ± 10% without generating dust to the outside. It may also include a step of coating and permeating in an amount not exceeding 0.1 ohm / cm ² . Usually Zn, Al
Such low melting point metal spraying is performed by arc (electric) and gas spraying methods. Uniformity of the sprayed film for electromagnetic wave shielding is extremely important because it is extremely reluctant to have defects in the film that cause leakage of electromagnetic waves. The arc type thermal spraying method is more advantageous than the gas type in this respect, and therefore the arc type thermal spraying method is most preferable in the present invention. Further, the arc type thermal spraying method has a large amount of thermal spraying, and has an advantage that the capacity can be further increased by simply increasing the number of thermal spraying guns.

Next, an embodiment of a manufacturing process as a means for embodying the method for manufacturing an electromagnetic wave shielding material of the present invention will be described with reference to the drawings. FIG. 2 is a conceptual diagram showing an example of manufacturing equipment of a method for manufacturing an electromagnetic wave shielding material of the present invention, which uses paper or cloth as a base material and includes a coating process of a penetrating paint. In the figure, reference numeral 5 is a spraying base material supply device, 6 is a spraying chamber, slits for passing the base material are formed on both sides, and a spray gun (not shown) is built-in. It is configured to perform thermal spraying while moving to the left and right in the chamber 6 so as to face the substrate surface. Reference numeral 10 denotes a dust collector, which has a strong suction force so as not to leak dust to the outside. Reference numeral 7 denotes a coating chamber which incorporates a coating means such as a spray or a roller coater (not shown) and an optional paint drying means. It goes without saying that the coating chamber 7 is omitted in the process in which coating is not performed.

Further, 8 is a product winding device, and 9 is a control device, which controls the moving speed of the spray gun, the spray chamber, and the moving speed of the base material to form a sprayed layer having an appropriate basis weight. It's something I got to get. FIG. 2 shown above shows an example of an embodiment in which a material that can be wound into a roll, such as paper or cloth, is used as the base material, but when using a gypsum board plate, plywood, particle board, etc. as the base material, Although not shown in the drawing, the feeding device 5 is a plate feeding device, a conveyor means is provided in the spraying chamber 6 or further in the coating chamber 7, and a stacking device such as a stacker is arranged in place of the winding device, so that paper, It is possible to carry out the manufacturing method of the present invention as in the case of cloth.

Next, the operation of the manufacturing equipment shown in FIG. 2 will be described. In this case, an example of using a roll-shaped base material such as paper or cloth as the base material will be described. First, after mounting the roll-shaped base material on the base material supply device 5, one end of the base material is attached to the thermal spray chamber 6 and if necessary. It is attached to the winding device 8 via the coating chamber 7. Thereafter, the supply device 5 and the winding device 8 are driven to move the base material from the left to the right in FIG. 2, and when passing through the thermal spray chamber 6, the thermal spray gun (not shown) built in the thermal spray chamber 6 is provided. A thermal sprayed layer is formed by moving right and left. In this case, as described above, the feed rate of the base material and the spraying conditions such as the spraying amount or the moving speed of the spray gun are controlled by the control device 9, and this means is particularly effective for the present invention. It is a thing.

Next, in the thermal spray chamber 6 in which the dust generated during thermal spraying does not leak, the dust is guided to the dust collector by a strong suction force and is removed, so that it does not come out at all. Taking the method of spraying Zn on the paper as an example, the strip-shaped paper that has entered through the slit of the spray chamber 6 is sprayed by a spray gun that moves from left to right. The amount of thermal spraying and the speed of the thermal spray gun and the paper are controlled by the controller 9, and the paper advances a certain distance each time the gun makes one turn from left to right (spraying). By repeating this, the basis weight is 70-300g
A uniform Zn sprayed electromagnetic wave shielding material of / m ² (± 10%) can be continuously manufactured without producing dust. Further, in this apparatus, instead of the roll-shaped paper or cloth, gypsum board plate, plywood or particle plate are continuously supplied, and thermal spraying → (after coating drying) → take out and integrate to obtain another embodiment of the present invention. It can be carried out.

When the coating process using the coating chamber 7 is included, the shield material having the sprayed layer is introduced into the coating chamber 7, and the penetrating coating material is applied by a coating means such as a spray or a roller coater as described above. Is applied and penetrates into the sprayed layer. A drying means (not shown) is additionally provided in the coating chamber 7 so that the coating material is quickly dried. In this case, the purpose of applying the penetrative paint is only for temporary rust prevention, not for complete rust prevention, so the coating amount may be small, as described above. Should not exceed 0.1 ohm / cm ² . As a means for controlling the coating amount, a means usually used at the time of coating the coating material can be appropriately selected and used.

Finally, the present invention will be described in more detail based on specific experimental results. Tables 1 and 2 show the electromagnetic wave shielding effect of the electromagnetic wave shielding material according to the present invention, its joint bonding method, and the comparative material. In Tables 1 and 2, No.
1, 17, 20, and 23 are comparative examples in which the basis weight is outside the range of the present invention, and Nos. 28 and 29 are reference examples in which the shielding performance of a single metal plate is compared for reference. The material is an example of the present invention. Shield effect is MIL-STD-
According to 285, the frequency was measured at 200 MHz. The test materials were Zn, Al, Zn-5% Al alloy, Zn-Al as the base material.
Was mixed and sprayed and cut into 15 cm × 15 cm × t. 1 mm hard vinyl chloride board for sprayed paper and cloth 2
The test material was sandwiched between the sheets, and the sprayed gypsum board plate, plywood or particle plate was shaved on the back surface and measured with a thickness of 2 mm. As a reference example, the joint material and the joint material are C as described above.
u and Al plates were added.

In this case, as the joint material, No. 12 material was used, the center of the specimen was cut straight with a cutter knife, and a 1 mm wide gap (corresponding to joint 2 in FIG. 1) was formed in the hard PVC plate. After leaving it open and applying it using a fusuma glue as an adhesive, as a seam joining means, affix the tape-shaped seam material cut into a width of 3 cm in the gap with the fusuma glue in the same manner as in FIG. And a bonded sample was prepared. Acrylic lacquer was applied thinly on the case of coating after thermal spraying.
It should be noted that the amount of coating, that is, No. 11, 15, 1
For 6, 25, 27, 46 and 48, the surface resistivities after drying were all 0.1 ohm / cm ² or less.
On the other hand, as described above, No. 1, 17, 20, 23
Is a comparative example in which the basis weight of the thermal sprayed layer is less than 70 g / m ² and is out of the range of the present invention. The shield performances of these test materials are shown in Tables 1 and 2. That is, the basis weight of thermal spraying is 1
It is sufficient if it is at least 0 to 130 g / m ² , and it is almost equivalent to the No. 29 Al plate and the No. 28 Cu plate. Also Z
There was almost no difference between the n, Al, Zn-5% Al alloy and the Zn-Al mixed spray material. This can be considered as follows.

The electromagnetic wave shielding effect is exerted by the sum of reflection loss, absorption loss and multiple reflection loss, and the dependence of each loss changes depending on the frequency, the type, form and thickness of the metal. For example, the shielding effect of a thin metal plate in the low frequency range is dominated by absorption loss,

[Equation 1] (G: specific conductivity, u: relative permeability), the specific conductivity of the metal,
Relative permeability will be involved. However, since the sprayed coating is a coating in which metal particles are piled up intricately, the invading electromagnetic wave repeats reflection loss, absorption loss, multiple reflection loss at the interface of multiple metal particles, and the spatial impedance at the reflection loss is also added. It is considered that the sprayed film has a greater shielding effect than the same metal plate. In other words, the shield performance of the metal sprayed film is affected by the physical shape of the film rather than the specific conductivity and relative permeability of the metal, and as a result, Zn, Al,
It is considered that the Zn-Al alloy sprayed material had almost no difference in metal species.

Also, there was almost no difference between the substrates (paper and cloth and gypsum board, plywood or particle board). For the seam of the seam joint material, sufficient shielding performance was obtained by simply adhering the tape-shaped thermal spray paper with glue, and even the material thinly coated after thermal spraying had no problem in seam joint. The rust resistance of the test material was evaluated by the time until the white rust was generated after the indoor exposure, but the rust resistance changes depending on the humidity and the temperature, so the average values of several tests were compared. That is, assuming that Zn spraying is 1.0, Zn spraying + coating is 2.8, Al spraying is 5.0, Zl-5% Al.
The alloy spraying showed good corrosion resistance of 3.5, and the Zn-Al mixed spraying showed good corrosion resistance of 3.0 times. The accuracy of the basis weight of the sprayed layer in each of the examples of the present invention was in the range of ± 10%, and there was no problem at all.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

INDUSTRIAL APPLICABILITY As in the present invention, Zn, Al, Zn-A can be applied to paper, cloth and gypsum board, alloy or particle board.
Electromagnetic wave shielding material obtained by spraying l alloy with no pollution, high efficiency and high precision has excellent electromagnetic wave shielding effect, and especially seam treatment (bonding) compared to conventional Cu, Al, Fe plates (foil)
Is extremely simple, efficient and inexpensive, and has a great utility value as a shield construction method. For example, sprayed paper or cloth can be applied to a shield room, anechoic chamber, or the inner wall of an architectural building in the same way as normal wallpaper attachment work, and the joints of seams are expensive conductive pastes, tapes and workability as in the conventional method. There is no need for bad soldering or welding, and the excellent shielding effect can be achieved by the extremely simple work of sticking the thermal spray paper (cloth) tape of the present invention to the seam using ordinary glue or adhesive. . The shield material sprayed on gypsum board, plywood, or particle board is easier to work. After these materials are attached to the wall, the same spray paper (cloth) is used at the seam.
An excellent shield effect can be achieved just by applying tape.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a seam joining method for an electromagnetic wave shielding material according to the present invention.

FIG. 2 is a conceptual diagram of a facility for manufacturing an electromagnetic wave shield material of the present invention.

[Explanation of symbols]

 1 Shielding Material 1a Tape 2 Seam 3 Thermal Spray Layer 4 Adhesive 5 Base Material Supply Device 6 Thermal Spray Chamber 7 Coating Room 8 Product Winding Device 9 Control Device 10 Dust Collector

Claims (6)

[Claims] 1. Zn, A having a basis weight of 70 to 300 g / m ^2.
An electromagnetic wave shielding material which is easy to bond, characterized in that a thermal sprayed layer made of one or more of 1,1, Zn-Al alloys is formed on the surface of the base material by continuous thermal spraying. ^2. Zn, A having a basis weight of 70 to 300 g / m ^2.
An amount in which a thermal sprayed layer made of one or more of 1, 1, Zn-Al alloys is formed on the surface of the substrate by continuous thermal spraying, and the surface resistivity of which does not exceed 0.1 ohm / cm ² from above the thermal sprayed layer. An easy-to-join electromagnetic wave shield material characterized by being permeated with the above-mentioned penetrable paint. 3. The electromagnetic wave shielding material according to claim 1, wherein the base material is any one of paper, cloth, gypsum board, plywood, and particle board. 4. One or more Zn, Al and Zn-Al alloys having a basis weight of 70 to 300 g / m ² are continuously applied to the surface of the base material with a basis weight accuracy of ± 10% without generating dust to the outside. A method for producing an electromagnetic wave shielding material which is easy to bond and which is characterized by thermal spraying. 5. One or more Zn, Al and Zn-Al alloys having a basis weight of 70 to 300 g / m ² are continuously applied to the surface of the base material with a basis weight accuracy of ± 10% without generating dust to the outside. A method for producing an electromagnetic wave shielding material which is easy to join, characterized in that after being thermally sprayed, an osmotic coating is applied and permeated onto the sprayed surface in an amount such that the surface resistance value does not exceed 0.1 ohm / cm ² . 6. The method of producing an electromagnetic wave shielding material according to claim 4, wherein the substrate is paper, cloth, gypsum board, plywood, or particle board.