JP2005320217A - Electromagnetic wave shielding material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cheap and endurable electromagnetic wave shielding material. <P>SOLUTION: This is a material combining a ferrite inorganic particulate or crashed matter with a binder. Ferrite inorganic matter is chemically stable and endurable, and especially an electric furnace oxidized slag is cheap and useful. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electromagnetic wave shielding material.

  Conventionally, as electromagnetic wave shielding materials, for example, synthetic resin, concrete, etc., in which metal powder is mixed, a metal net is inserted, or a metal thin film is attached (see, for example, Patent Document 1). ).

JP 2001-352193 A Japanese Patent Laid-Open No. 10-163675

  Metal powders, metal nets, or metal thin films are very expensive and easily corroded, and metal nets and metal thin films have a problem that they have a low mechanical strength and are easily damaged.

The present invention provides an electromagnetic wave shielding material obtained by binding a ferrite-based inorganic granular material or crushed material with a binder as a means for solving the above conventional problems.
The binder is preferably a hydraulic inorganic material or synthetic resin and / or rubber and / or asphalt or a ceramic raw material, and the ferrite-based inorganic granular material or crushed material is an electric furnace oxidation slag granular material 8 or crushed material. Is desirable.
The electric furnace oxidation slag is obtained by adding an additive for improving electromagnetic wave shielding properties to the electric furnace oxidation slag melt 1, blowing in air or oxygen and subjecting it to forced oxidation treatment, followed by rapid solidification. The modified electric furnace oxidation slag is desirable, and the additive for improving the electromagnetic wave shielding property is Fe, Ba, Co, Ni, Cr, Cu, Mn, Sr, Zn and oxidation of these metals. It is desirable to be a metal compound that gives an oxide by heating or heating. Further, the electromagnetic wave shielding material is a plate body, and it is desirable that a metal net is mounted on the opposite side of the plate body to the electromagnetic wave incidence.

[Action]
In the electromagnetic wave shielding material of the present invention, the ferrite-based inorganic granular material or crushed material bound by the binder has high hardness, high mechanical strength and corrosion resistance, and hardly changes even in the above composition. Therefore, durable electromagnetic shielding properties can be obtained.
If an electric furnace oxidation slag granular material or crushed material is used as the ferritic inorganic granular material or crushed material, the electric furnace oxidation slag is very inexpensive and highly practical. The electric furnace oxidation slag was obtained by adding an additive for improving electromagnetic wave shielding properties to an electric furnace oxidation slag melt, blowing air or oxygen and subjecting it to forced oxidation treatment, followed by rapid solidification. If the reformed electric furnace oxidation slag is used, the electromagnetic wave shielding property is further improved.
The electromagnetic wave shielding material of the present invention is mainly provided as a plate, but when a metal net is attached to the opposite side of the plate from which electromagnetic waves are incident, the electromagnetic wave can be obtained even if the thickness of the plate is as thin as several millimeters. The shielding property, particularly the magnetic field shielding effect, is greatly improved. The metal net particularly shields the magnetic field by reflecting the electromagnetic wave, but the reflected electromagnetic wave is absorbed by the plate body made of the electromagnetic wave shielding material of the present invention in which the ferrite-based inorganic particulate matter or crushed material is dispersed, and the plate body Almost no leakage from the surface.

〔effect〕
In the present invention, an electromagnetic wave shielding property is imparted by adding an inexpensive corrosion-resistant ferrite-based inorganic granular material or crushed material to a binder such as a hydraulic inorganic material, a synthetic resin, or a ceramic raw material. An inexpensive material having properties is provided.

The present invention is described in detail below.
[Hydraulic inorganic powder]
Examples of the hydraulic inorganic powder used as a binder in the present invention include Portland cement, alumina cement, blast furnace cement and other cements or blast furnace quenching slag fine powder, electric furnace quenching reduced slag fine powder, silica sand to the cement, Examples thereof include silica powder, silica fume, blast furnace slag fine powder, fly ash, shirasu balloon, pearlite, bentonite, and mixed powder to which a silicate-containing substance such as diatomaceous earth is added.

[Synthetic resin]
Examples of the synthetic resin used as a binder in the present invention include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-propylene terpolymer, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, polystyrene, Thermoplastics such as vinyl acetate, fluororesin, thermoplastic acrylic resin, thermoplastic polyester, thermoplastic polyamide, thermoplastic urethane resin, acrylonitrile-butadiene copolymer, styrene-butadiene copolymer, acrylonitrile-butadiene-styrene copolymer Examples include thermosetting resins such as resins, urethane resins, melamine resins, thermosetting acrylic resins, urea resins, phenol resins, epoxy resins, thermosetting polyesters, etc. resin Repolymer, epoxy resin prepolymer, melamine resin prepolymer, urea resin prepolymer, phenolic resin prepolymer, diallyl phthalate prepolymer, acrylic oligomer, polyvalent isocyanate, methacrylic ester monomer, diallyl phthalate monomer, etc. May be.
Two or more of the above synthetic resins and / or synthetic resin whole casings may be mixed and used.

[Rubber]
Examples of the rubber used as the binder in the present invention include acrylic rubber, butyl rubber, silicon rubber, urethane rubber, fluoride rubber, polysulfide rubber, graft rubber, butadiene rubber, isoprene rubber, chloroprene rubber, and polyisobutylene rubber. Synthetic rubber such as polybutene rubber, isobutene-isoprene rubber, acrylate-butadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, pyridine-butadiene rubber, styrene-isoprene rubber, acrylonitrile-chloroprene rubber, styrene-chloroprene rubber, and natural rubber Styrene thermoplastic elastomers such as styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, styrene-hydrogenated polyolefin-styrene copolymer, and pig Ene - styrene Proc copolymer, styrene - rubber midblock - elastomer block copolymers such as styrene copolymers.
Two or more of the above rubbers and / or elastomers may be used in combination.

〔asphalt〕
The asphalt used as a binder in the present invention includes any kind of asphalt, such as blown asphalt, asphalt compound, straight asphalt, bitumen such as tar, pitch, etc., and a mixture of two or more kinds thereof. Good.

[Ceramic raw materials]
As the ceramic raw material used as a binder in the present invention, plastic raw materials such as kaolin, glazed clay, kibushi clay, rhodolite clay, setter clay, bentonite, non-plasticity such as silica, wax stone, and ground powder Examples include raw materials, solvent materials such as feldspar, porcelain stone, sericite, and talc, and other ceramic materials such as alumina, magnesia, zirconia, titania, beryllia, tria, spinel, and selshan.

〔binder〕
Synthetic resin, rubber and asphalt as the binder may be mixed with each other. For example, rubber is added to improve the heat resistance of asphalt, rubber (elastomer) is added to improve the impact resistance of synthetic resins, and asphalt is added to improve soundproofing. The

[Ferrite mineral]
The ferritic mineral used in the present invention contains M ^II O · Fe ₂ O ₃ , and M ^II includes Fe, Ba.
The cerite-based inorganic material contains FeO.Fe ₂ O ₃ .
As the ferritic inorganic material, it is desirable to use scale powder or electric furnace oxidation slag generated when fusing steel. These ferrite minerals can be obtained at low cost.
The electric furnace oxidation slag is usually CaO 10 to 26% by mass, SiO ₂ 8 to 22% by mass, MnO 4 to 7% by mass, MgO _{2 to} 8% by mass, FeO 13 to 32% by mass, Fe ₂ O ₃ 9 to 45% by mass, Al. ₂ O ₃ 4 to 16% by mass, Cr ₂ O ₃ 1 to 4% by mass, and trace components BaO 0.05 to 0.20% by mass, TiO ₂ 0.25 to 0.70% by mass, P ₂ O ₅ 0.15 to 0.50% by mass, S 0.005 to 0.085% by mass, including about 20 to 45% by mass of Fe for obtaining a stable mineral composition, and included in natural aggregate components It contains no clay, organic impurities or salt, and contains almost no unstable free lime, free magnesia or minerals. The electric furnace oxidation slag is provided as a granular material or a crushed material.

[Electric furnace oxidation slag granulation method]
In order to granulate the electric furnace oxidation slag, a granular material is produced by injecting a melt of the electric furnace oxidation slag into a bladed drum rotating at high speed, and crushing and granulating the melt with the bladed drum. A method of quenching the melted melt in a water mist atmosphere is employed. A plurality of bladed drums may be arranged to perform a plurality of stages of crushing and granulating.
Since the granular material of the electric furnace oxidation slag obtained in this way promotes re-oxidation, it contains a large amount of Fe ₂ O ₃ mineral and becomes ultrafine granular material by rapid cooling. Will be very good. In addition, usually those having a particle size of 5 mm or less, those having a particle size of 2.5 mm or less are substantially spherical, the specific gravity is in the range of 3.3 to 4.1, and there are no defects such as cracks on the surface, and fine And have a hollow structure or a hollow structure.

[Electric furnace oxidation slag crushing method]
In order to manufacture the electric furnace oxidized slag crushed material, the electric furnace oxidized slag is poured into a heat-resistant container in a molten state to a predetermined thickness, and subjected to rapid cooling reforming by pouring water from above. In this case, if the thickness of the slag melt in the heat-resistant container is too small, it tends to harden by natural cooling (slow cooling) before applying water, and the desired hardness may not be obtained. If it becomes too large, when water is applied, the water suddenly becomes water vapor and there is a danger of water vapor explosion. A desirable slag melt thickness is 80 mm to 120 mm.

When water is applied, it is desirable to prevent water from accumulating on the surface of the slag melt in the heat-resistant container. Too much water is applied and water accumulates on the surface of the slag melt. The rapid cooling effect due to the latent heat of vaporization cannot be expected.
The amount of water applied is preferably about 200 to 400 liters per second per ton of slag melt.
The slag melt is rapidly cured by the rapid cooling, and at this time, a slag ingot having a diameter of about the thickness of the slag melt in the container is obtained by self-crushing.

  The slag bulk is crushed by a pulverizer and further pulverized by a pulverizer. By the pulverization, the slag lump is broken at the boundary between the slag component matrix and the mineral phase, and fine irregularities are formed on the surface. If desired, the crushed material is coarsely classified by a coarse sieving machine, etc., and further subdivided by a fine pulverizer or the like to give coarse aggregate of 5 to 25 mm, preferably 5 to 20 mm, and a coarse particle size of 5 to 13 mm, preferably 5 to 10 mm. Divide into aggregates and fine aggregates of 5mm or less.

The above crushing and pulverization may be carried out while the slag block is wet with water, or the slag block may be dried and subjected to the steps after crushing, or the slag block may be crushed. Then, it may be dried to carry out the steps after grinding. Moreover, in the said classification process, it is desirable to return the residue which does not pass a sieve to a crushing process.
Since the crushed material obtained in this way promotes reoxidation as compared with slow-cooled slag, it contains a lot of Fe ₂ O ₃ minerals and becomes a fine granular material by rapid cooling. It becomes very good, and its specific gravity is in the range of 3.3 to 4.1 like the granulated product.

[Reformed electric furnace oxidation slag]
Furthermore, you may add the additive for improving electromagnetic wave shielding to the composition of this invention.
Examples of the additive for improving the electromagnetic wave shielding property include metals such as Fe, Ba, Co, Ni, Cr, Cu, Mn, Sr, and Zn, alloys containing these metals, oxides of these metals, and hydroxylation. Compounds that give oxides upon heating such as chlorides, chlorides and sulfates. Desirable additives include iron scrap, scale, BaO scrap, barite containing barium sulfate, and the like.
In the granulation method or crushing method, the additive is added to the electric furnace oxidation slag melt or mixed with the electric furnace oxidation slag and melted together. The melting is usually performed in an electric melting furnace. At this time, air or oxygen is blown into the melt to perform forced oxidation treatment. The forced oxidation treatment is effective against slug especially by FeO ratio is high fracturing, by the forced oxidation treatment Fe ₂ O ₃ ratio of the can of improving an electromagnetic wave shielding properties to enhance.
The reformed electric furnace oxidation slag is also provided as a granular or crushed material.

〔aggregate〕
In the present invention, fine aggregate and coarse aggregate may be further added. The fine aggregate has a particle size of 5 mm or less. As such a fine aggregate, for example, the electric furnace oxidation slag granular material having a particle size of 5 mm or less, sand having a particle size of 5 mm or less, or the like is used. .
Instead of a part of the fine aggregate, coarse aggregate such as crushed stone or gravel having a particle diameter of 5 to 25 mm may be used in the present invention.

[Water reducing agent]
When a hydraulic inorganic powder is used as a binder, it is preferable to add a water reducing agent to the mixture of the ferrite inorganic granular material or crushed material and the hydraulic inorganic powder.
Examples of the water reducing agent used in the present invention include an AE water reducing agent and a high performance AE water reducing agent.

[Thickener]
In the present invention, when a synthetic resin emulsion or rubber latex is used as the binder, the viscosity of the ferrite inorganic granular material or the mixture of the crushed material and the binder, and when the binder is a hydraulic inorganic powder, the ferrite inorganic material is used. A thickener may be used to adjust the viscosity when a powder composition mainly composed of a mixture of a granular material or a crushed material, or a mixture obtained by mixing a water reducing agent in the mixture is kneaded with water. For example, when the binder is a hydraulic inorganic powder, if the kneaded product with water exceeds 3% in the breathing test, a thickener is used to reduce this to 3% or less. Examples of the thickener include glue, gelatin, casein, starch, modified starch, oxidized starch, dextrin, gum arabic, sodium alginate, polyvinyl alcohol, carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, sodium polyacrylate, and sodium polymethacrylate. , Polyacrylamide, polymethacrylamide, polyvinyl methyl ether, vinyl acetate-maleic acid copolymer, styrene-maleic acid copolymer, polyvinyl pyrrolidone, polyacrylate partial saponified product, polymethacrylate partial saponified product, etc. There are functional polymers.

[Metal mesh]
When a metal net is inserted into the electromagnetic wave shielding material of the present invention, the electromagnetic wave shielding property is greatly improved. As the material of the wire of the metal net, iron, copper, aluminum, stainless steel or the like is used, and the diameter of the wire is usually 0.1 mm to 1.0 mm, and the mesh size is 0.5 mm square to 5 mm square. Degree.

[Formulation, molding]
In the present invention, when the binder is a hydraulic inorganic material, usually 15 to 60 parts by mass of a hydraulic inorganic powder, a water reducing agent and / or a thickener 0.01 to 3 parts per 100 parts by mass of a ferrite-based inorganic granular material or crushed material. 0.0 parts by weight are mixed. When the addition amount of the hydraulic inorganic powder exceeds 60 parts by mass, the electromagnetic wave shielding property is deteriorated. When the addition amount is less than 15 parts by mass, the binding force of the binder is reduced, and the strength of the molded article is not sufficiently exhibited.

5 to 25 parts by mass of water is added and kneaded with respect to 100 parts by mass of the powder mixture, the kneaded product is filled in a mold, and cured by heating and curing at normal temperature or with steam or electromagnetic waves if desired. The shape of the molded product is various shapes such as a plate shape, a slab shape, and a block shape.
Furthermore, the kneaded material may be poured directly onto the road foundation or building floor without being filled in the formwork, or directly applied to the wall surface.

  In the present invention, when the binder is a synthetic resin and / or rubber, the synthetic resin and / or rubber is usually mixed in an amount of 5 to 200 parts by mass as a solid content with respect to 100 parts by mass of the ferrite-based inorganic granular material or crushed material. When the addition amount of the synthetic resin and / or rubber exceeds 200 parts by mass, the electromagnetic wave shielding property is deteriorated. When the addition amount is less than 5 parts by mass, the binding force of the binder is reduced, and the strength of the molded article is not sufficiently exhibited.

  The synthetic resin and / or rubber is usually provided as a powder, granules, emulsion or latex, or an organic solvent solution. When the synthetic resin and / or rubber is powdery or granular, it is mixed with ferrite inorganic granular material or crushed material, and if desired, heated, melted and stirred, and the mixture is injection molded, extruded, calendered, stamped, etc. Alternatively, the mixture is extruded by an extruder and pelletized (granulated), and the pellet is formed by injection molding, extrusion molding, calendar molding, stamping molding, or the like. Further, when formed into a sheet by extrusion molding or calender molding, if desired, it is further molded into a desired shape by vacuum and / or pressure forming or press molding.

  When the synthetic resin and / or rubber is an emulsion or latex, the ferrite-based inorganic granular material or crushed material is added and mixed, and usually molded by a casting method. Further, a sheet formed by casting may be formed into a desired shape by vacuum and / or pressure forming, press forming, or the like.

  In the case of a liquid synthetic resin whole body, it is formed into a resin in the same manner as the emulsion and latex.

  In the present invention, when the binder is asphalt, usually 5 to 50 parts by mass of asphalt is mixed with 100 parts by mass of the ferrite-based inorganic granular material or crushed material. When the amount of asphalt added exceeds 50 parts by mass, the electromagnetic wave shielding property is deteriorated. When the amount of asphalt is less than 5 parts by mass, the binding force of the binder is reduced, and the strength of the molded article is not sufficiently exhibited.

  In the present invention, when the binder is a ceramic raw material, usually 10 to 40 parts by mass of the ceramic raw material is mixed with 100 parts by mass of the ferrite-based inorganic granular material or crushed material. When the amount of the ceramic raw material exceeds 40 parts by mass, the electromagnetic wave shielding property is deteriorated. When the amount is less than 10 parts by mass, the binding force of the binder is reduced and the strength of the molded article is not sufficiently exhibited.

[Example 1] (Production of electric furnace slag granules)
FIG. 1 shows an apparatus for producing an electric furnace slag granular material (hereinafter abbreviated as slag granular material) 8 of the present invention.
That is, the electric furnace oxidation slag melt 1 around 1500 ° C. is transferred from the electric melting furnace to the ladle 2, transferred from the ladle 2 to the shooter 3, and injected from the shooter 3 to the bladed drums 4 and 5 that rotate at high speed. . The steelmaking slag melt 1 is crushed and granulated by the bladed drums 4, 5, and the granulated product 1 A of the electric furnace oxidation slag melt is quenched by water mist sprayed from the spray device 7 into the quenching chamber 6. Is done. And the slag granular material 8 obtained in this way is stored in the storage container 9.
The slag granular material 8 is a substantially spherical hollow body, has no defects such as cracks on the surface, has fine irregularities, and has high hardness (Mohs hardness of about 6 matrix and mineral phase of about 8). ) And has excellent wear resistance, true specific gravity of 3.84, absolute dry specific gravity of 3.52, fire resistance of 1100 ° C., electromagnetic shielding properties, magnetic permeability, dielectric properties, acid resistance, alkali resistance, etc. Is excellent.
The particle size distribution of the slag granular material 8 is shown in FIG.

[Example 2] (Manufacture of electric furnace slag crushed material)
In Example 1, iron powder, calcium oxide, and silicon oxide are post-added to the molten slag transferred from the electric melting furnace to the ladle 2 to adjust to the following composition.
CaO 24.92 mass%
SiO ₂ 15.24% by mass
Al ₂ O ₃ 6.72% by mass
MnO 5.66 mass%
MgO 4.25% by mass
Cr ₂ O ₃ 1.97% by mass
TiO ₂ 0.42 mass%
BaO 0.07 mass%
Total Fe 40.75 mass%
CaO / SiO ₂ = 1.64
The slag melt is heated to about 1350 ° C., but is poured out of the ladle 2 into a heat-resistant container (made of dish-shaped steel) to a thickness of about 100 mm, and immediately, 300 liters per second per ton of slag melt is sprayed. Sprinkle water.

  In this way, a slag bulk having a diameter of about 100 mm was obtained, and the Mohs hardness of the slag bulk was 6 in the matrix and 8 in the mineral phase. The slag bulk is crushed with a crusher, dried with a drier and then pulverized with a crusher. The crushed slag ingot is then coarsely classified by a coarse sieve machine, and further finely classified by a fine sieve machine to obtain a coarse aggregate having a particle size of 5 to 20 mm or a coarse aggregate having a particle size of 5 to 13 mm, and a particle size of 5 mm or less. Divided into fine aggregates.

[Example 3] (Production of crushed reformed electric furnace slag)
4.5 tons of electric furnace oxidation slag 1 is put into an electric melting furnace 10 equipped with an electrode 11 shown in FIG. 3, and 1.5 tons of paddy palai and 125 kg of barite are added as iron scrap, and a lance pipe Oxygen is blown from 12 and heated and melted, and the resulting melt 1A is transferred to the ladle 2 shown in FIG. 1, and the reformed electric furnace oxidation slag crushed material is obtained in the same manner as in Example 2.
An example of the chemical composition of the reformed electric furnace oxidized slag crushed material is shown in Table 1.

[Example 4] (hydraulic inorganic material)
(1) Preparation of electromagnetic wave shielding cement composition A The following compositions were mixed.
Portland cement 21% by mass
Electric furnace oxidation slag granular material * 1 78 〃
Ultra fine powder cement * 2 1 〃
* 1: Electric furnace oxidation slag granules of Example 1 (particle size 2.5 mm or less)
* 2: 45 μm or less, used for the purpose of reducing fluidity by improving fluidity.
(2) Preparation of molded article sample The composition shown in Table 2 was mixed using the composition A.

The slurry having the above composition was poured into a mold and cured and cured to prepare plate-shaped molded product samples C-1 to C-5 having a size of 150 mm × 150 mm and a thickness of 3 mm. In C-2 and C-3, the slurry was poured in a state where the steel mesh was inserted into the bottom of the mold, and a plate-shaped molded product sample having a steel mesh mounted and fixed on one side was prepared.
(3) Preparation of comparative molded product Portland cement 2200g, mountain sand (particle size 2.5mm or less) 4450g (Portland cement: mountain sand = 1: 1 capacity), super fine powder cement 175g, AE water reducing agent 40g Then, a slurry mixed with 800 g of water was poured into a mold and cured and cured to prepare a plate-shaped comparative molded product sample having a size of 150 mm × 150 mm and a thickness of 3 mm.
(4) Electromagnetic wave shielding sample The electric field shielding effect and the magnetic field shielding effect at various frequencies were examined for the samples C-1 to C-5 and the comparative molded product samples. In C-2 and C-3, electromagnetic waves were applied from the opposite side of the steel net. The results are shown in FIGS. 4a, b to 9a, b.
Fig. 4a: Field shielding effect of C-1 b: Magnetic field of C-1
Fig. 5a: Electric field shielding effect of C-2 〃b: Magnetic field of C-2 〃
Fig. 6a: Electric field shielding effect of C-3 〃b: Magnetic field of C-3 〃
Fig. 7a: Electric field shielding effect of C-4 〃b: Magnetic field of C-4 〃
Fig. 8a: Electric field shielding effect of C-5 〃 b: Magnetic field of C-5 〃
Fig. 9a: Electric field shielding effect of comparative molded product sample 〃b: Magnetic field of comparative molded product sample 〃

  Referring to FIGS. 4a and b to FIGS. 9a and b, each of C-1 to C-5 added with electric furnace oxidation slag has a higher electric field shielding property than a comparative molded product sample without addition of electric furnace oxidation slag. It is recognized that the electromagnetic wave shielding property, particularly the magnetic field shielding property is greatly improved by the installation of the steel mesh (C-2, C-3). It is recognized that the finer mesh A having a smaller mesh size has higher magnetic field shielding properties (C-2).

[Example 5] (hydraulic inorganic material)
The compositions in Table 3 were mixed.

A slurry having the above composition was poured into a mold and cured and cured to prepare a plate-shaped molded product sample having a size of 150 mm × 150 mm and a thickness of 3 mm. In C-6 and C-7, the slurry was poured in a state in which a copper mesh was inserted into a mold, and a plate-shaped molded product sample having a copper mesh mounted and fixed on one side was prepared.
The molded products C-6 to C-8 were examined for electric field shielding effect and magnetic field shielding effect at various frequencies. In C-6 and C-7, electromagnetic waves were applied from the opposite side of the copper net. The results are shown in FIGS. 10a, b to 12a, b.
Fig. 10a: Electric field shielding effect of C-6 〃 b: Magnetic field of C-6 〃
Fig. 11a: Electric field shielding effect of C-7 ｂ b: Magnetic field of C-7 〃
Fig. 12a: Electric field shielding effect of C-8 ｂ b: Magnetic field of C-8 〃

  Referring to FIGS. 10a and b to 12a and b, C-8 added with a cutter scale has almost no difference compared to the result of C-1, and the effect of improving the electromagnetic wave shielding property by adding the cutter scale is not recognized. However, C-6 and C-7 fitted with a copper mesh showed a significant improvement in the electromagnetic wave shielding effect, particularly the electric field shielding effect, and the effect was obtained when a steel mesh was inserted (C-2, C-3). It is recognized that it is slightly higher than that. Also in the copper net, it is recognized that the electromagnetic wave shielding effect is higher in the net B having a finer wire and a smaller mesh size.

[Example 6] (Synthetic resin)
(1) Preparation of binder composition B The following composition was mixed.
Acrylic resin emulsion * 1 132 parts by mass Portland cement 88 〃
AE water reducing agent 4.4 〃
Methylcellulose 0.7 〃
Defoamer 0.6 〃
* 1: Product name Acronal, solid content 50% by mass
(2) Preparation of molded product sample The composition shown in Table 4 was mixed with 225.7 g of the composition B.

The above composition was poured into a mold and dried and cured at room temperature to prepare plate-shaped molded product samples R-1 to R-8 having a size of 150 mm × 150 mm and a thickness of 3 mm. In R-3, R-4, and R-5, the above composition is poured in the state where the copper mesh or steel mesh is inserted into the bottom of the mold, and a plate shape in which the copper mesh or steel mesh is mounted and fixed on one side. A molded product sample was prepared.
The electric field shielding effect and the magnetic field shielding effect at various frequencies were examined for the molded product samples R-1 to R-8 and the comparative sample 4. In R-3, R-4, and R-5, electromagnetic waves were applied from the opposite side of the copper net or steel net. The results are shown in FIGS. 13a, b to 21a, b.
Fig. 13a: Field shielding effect of R-1 〃 b: Magnetic field of R-1 〃
Fig. 14a: Electric field shielding effect of R-2 ｂ b: Magnetic field of R-2 〃
Fig. 15a: Electric field shielding effect of R-3 ｂ b: Magnetic field of R-3 〃
Figure 16a: R-4 electric field shielding effect 〃 b: R-4 magnetic field 〃
Fig. 17a: Electric field shielding effect of R-5 〃 b: Magnetic field of R-5 〃
18a: Electric field shielding effect of R-6 〃 b: Magnetic field of R-6 〃
19a: Electric field shielding effect of R-7 〃 b: Magnetic field of R-7 〃
Figure 20a: Electric field shielding effect of R-8 〃 b: Magnetic field of R-8 〃
Fig. 21a: Electric field shielding effect of comparison 1 ｂ b: Magnetic field of comparison 1 〃

Referring to FIGS. 13a and b to FIGS. 21a and b, R-1, R-2, R-3, R-4, and R-5 added with electric furnace oxidation slag all have an electromagnetic wave shielding effect. Comparative 1 with no addition of electric furnace oxidation slag shows little electromagnetic shielding effect. Moreover, about R-1 and R-2 which changed the particle size of the electric furnace oxidation slag, electromagnetic wave shielding property is substantially equivalent, and about R-3, R-4, and R-5 which inserted the metal net | network, any A significant improvement in electromagnetic shielding properties is observed.
Furthermore, in R-6, R-7, and R-8 using carbon fiber, iron powder, K-shot scraps, etc., the electromagnetic wave shielding performance is greatly improved over R-6 using carbon fiber. However, a slight improvement in electromagnetic shielding properties was also observed in R-7 and R-8 using iron powder and K-shot dust together.

[Example 7] (Rubber)
A mixture of the following formulation was prepared:
Electric furnace oxidation slag granular material of Example 1 (5 mm or less) 100 parts by mass Chloroprene rubber 60 〃
Zinc oxide 0.6〃
Sulfur 0.3〃
The mixture was melted and kneaded by heating and extruded into a sheet having a thickness of 5 mm through a T die.
A 500 × 500 mm square sample was cut out from the sheet, and the electromagnetic shielding effect was examined. The result is shown in FIGS. 22a and 22b. Referring to the drawing, it is recognized that the electric field shielding effect is particularly remarkable.

  Since the electromagnetic wave shielding material of the present invention is inexpensive and has good electromagnetic wave shielding properties, for example, a building housing such as an office that performs IT-related work, a medical diagnosis, or a hospital that performs medical treatment, or a wall material or floor material. In particular, it is also useful for countermeasures against ghost of TV radio waves caused by buildings and structures.

Explanatory drawing of electric furnace slag granular material manufacturing equipment Graph showing the particle size distribution of electric furnace slag granules FIG. 4 to FIG. 22 are graphs of the results of examining the electric field shielding effect a and the magnetic field shielding effect b for the samples prepared in Examples 4 to 7, and the vertical axis represents the attenuation (dB), The horizontal axis represents frequency (MHz). a: Electric field shielding effect of sample C-1 ｂ b: Magnetic field shielding effect of sample C-1 a: Electric field shielding effect of sample C-2 〃 b: Magnetic field shielding effect of sample C-2 a: Electric field shielding effect of sample C-3 〃 b: Magnetic field shielding effect of sample C-3 a: Electric field shielding effect of sample C-4 〃 b: Magnetic field shielding effect of sample C-4 a: Electric field shielding effect of sample C-5 ｂ b: Magnetic field shielding effect of sample C-5 a: Electric field shielding effect of sample C-6 〃 b: Magnetic field shielding effect of sample C-6 a: Electric field shielding effect of sample C-6 〃 b: Magnetic field shielding effect of sample C-6 a: Electric field shielding effect of sample C-7 〃 b: Magnetic field shielding effect of sample C-7 a: Electric field shielding effect of sample C-8 〃 b: Magnetic field shielding effect of sample C-8 a: Electric field shielding effect of sample R-1 〃 b: Magnetic field shielding effect of sample R-1 a: Electric field shielding effect of sample R-2 〃 b: Magnetic field shielding effect of sample R-2 a: Electric field shielding effect of sample R-3 〃 b: Magnetic field shielding effect of sample R-3 a: Electric field shielding effect of sample R-4 〃 b: Magnetic field shielding effect of sample R-4 a: Electric field shielding effect of sample R-5 〃 b: Magnetic field shielding effect of sample R-5 a: Electric field shielding effect of sample R-6 〃 b: Magnetic field shielding effect of sample R-6 a: Electric field shielding effect of sample R-7 〃 b: Magnetic field shielding effect of sample R-7 a: Electric field shielding effect of sample R-8 〃 b: Magnetic field shielding effect of sample R-8 a: Electric field shielding effect of comparison 1 ｂ b: Magnetic field shielding effect of comparison 1 a: Electric field shielding effect of sample of Example 7 〃 b: Magnetic field shielding effect of sample of Example 7

Explanation of symbols

1 Electric furnace oxidation slag melt 8 Electric furnace slag granular material

Claims (8)

  An electromagnetic wave shielding material comprising a ferrite-based inorganic granular material or crushed material bound with a binder.   The electromagnetic wave shielding material according to claim 1, wherein the binder is a hydraulic inorganic material.   The electromagnetic wave shielding material according to claim 1, wherein the binder is a synthetic resin and / or rubber and / or asphalt.   The electromagnetic wave shielding material according to claim 1, wherein the binder is a ceramic raw material.   The electromagnetic wave shielding material according to claim 1, wherein the ferrite-based inorganic granular material or crushed material is an electric furnace oxidation slag granular material or crushed material.   The electric furnace oxidation slag was obtained by adding an additive for improving electromagnetic wave shielding properties to an electric furnace oxidation slag melt, blowing air or oxygen and subjecting it to forced oxidation treatment, followed by rapid solidification. The electromagnetic wave shielding material according to claim 5, wherein the electromagnetic wave shielding material is a modified electric furnace oxidation slag.   The additive for improving the electromagnetic wave shielding property is Fe, Ba, Co, Ni, Cr, Cu, Mn, Sr, Zn, an oxide of these metals, or a metal compound that gives an oxide by heating. 6. The electromagnetic wave shielding material according to 6.   The electromagnetic wave shielding material according to claim 1, wherein the electromagnetic wave shielding material is a plate, and a metal net is attached to the opposite side of the plate from which electromagnetic waves are incident.

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