JPH01173796A - Magnetic shielding material - Google Patents

Abstract

PURPOSE:To obtain a magnetic shielding material having a sufficient magnetic shielding effect even if it is made small in thick and consequently suitable for speakers, CRTs, and so forth by a method wherein amorphous alloy magneti cally soft particles to which average thickness and a ratio of average outer diameter to average thickness are specified are combined with polyurethane with a specified filling ratio. CONSTITUTION:Amorphous alloy magnetically soft particles to be used are specified to be 0.01-1mum in average thickness and 10-10000 in a ratio of aver age outer diameter to average thickness. Next, 60-95% by weight of the particles is mixed with polyurethane as a binding agent to form a magnetic shielding material. Here, the amorphous alloy is composed of ferromagnetic transition metal such as Fe, Co, Ni, or the like and semimetal such as B, Si C, or the like, and three elements, Fe-B-Si, are preferably utilized. And, the polyurethane as the binding agent is a polyaddition product formed of multiva lent isocyanate and polyol compound, and 2,4-toluen diisocyanate is used as the multivalent isocyanate.

Description

Detailed Description of the Invention ■ Background Technical Field of the Invention The present invention relates to a soft magnetic powder for magnetic shielding and a magnetic shielding material using the same, and in particular to a flat amorphous alloy soft powder that has a large shielding effect against magnetic fields in a specific direction. The present invention relates to a magnetic shielding material using soft magnetic powder for magnetic shielding consisting of magnetic particles.

Prior Art and its Problems Magnetic shielding materials are used to prevent magnetized objects and other sources of magnetic field from affecting other objects, electrical circuits, and the like. As a magnetic shielding material, a metal plate with high magnetic permeability is desirable from the viewpoint of shielding properties, but its applications are severely limited. In the case of powder materials, it can be dispersed in an organic binder and applied in the form of a paint to the areas where shielding is required, or
Alternatively, it is convenient because it can be used in a variety of ways, such as by coating it on a suitable flexible support or the like to make a shield plate.

Various proposals have been made for magnetic shielding materials using powder with high magnetic permeability. For example, JP-A No. 58-59268 discloses a magnetic shielding paint in which flat powder of a high magnetic permeability alloy is mixed into a polymer binder;
No. 3 shows a magnetic shielding paint in which flat powder obtained by pulverizing a soft magnetic amorphous alloy is mixed into a polymer binder.

Magnetic shielding materials using these flat powders have isotropic shielding characteristics between planes perpendicular to the thickness direction. In addition, alloy flat grains as shown in JP-A No. 59-201493 are produced by grinding a thin ribbon of a transition metal-metalloid (metalloid) alloy that is quenched at high speed by bringing it into contact with the surface of a cooling roll from a high-temperature molten state. Although the obtained powder is used, the lower limit of the thickness of the ribbon is 10 μm, and usually only about 10 to 50 μm can be obtained, and even if it is crushed into a scaly powder, the thickness of the powder will not change. Therefore, even if a magnetic shield coating film is manufactured from this powder, the shielding properties are very poor. Although the amorphous alloy itself has very good magnetic properties, such scaly powder does not make full use of its magnetic properties.

An example of a method of pulverizing a rapidly quenched alloy into flakes is shown in JP-A-58-197205. However, the pulverization method uses any of the conventionally known stamp mills, dry ball mills, wet ball mills, attritors, and vibration mills. Also, JP-A-60-401
The issue describes a method of embrittling rapidly quenched amorphous alloys in the form of sheets, ribbons, tapes, and wires at temperatures below the glass transition point and then pulverizing them. The methods used are rod mills, ball mills, surface mills, and disk mills. , stamp mill, crusher roll. However, these crushing means cannot crush sheets, ribbons, etc. to less than the minimum thickness, and can only obtain isotropic scale powder. Even if such a relatively large powder is made into a paint, it is difficult to apply it uniformly, and the magnetic shield obtained by applying the powder lacks magnetic uniformity, resulting in large leakage of the magnetic field.

The magnetic field to be shielded by a magnetic shield may be isotropic, but it is often strong in a specific direction. Even if powder is used for magnetic orientation during application, there is little effect.

In order to solve these problems, the inventors of the present invention defined the average thickness and average outer diameter/average thickness ratio of the powder in Japanese Patent Application No. 62-215857, thereby achieving a high shielding effect and uniformity. We are proposing magnetic shielding materials. Compared to conventional powder, this material has improved magnetic shielding effect in the direction parallel to the film surface even when made into a thin film, but the requirements for magnetic shielding are strict, and even more effective magnetic shielding materials are required. .

■! OBJECTS OF THE INVENTION An object of the present invention is to provide a magnetic shielding material that has good magnetic shielding properties in the direction parallel to the film surface even when the film is thinned, and has high strength.

II! Disclosure of the invention Such objects are achieved by the invention described below.

That is, the present invention provides a magnetic shielding material containing soft magnetic powder and a binder, wherein the soft magnetic powder has an average thickness of 0.01 to 1 μm and an average outer diameter/average thickness ratio of 10 to 10,000. A magnetic shielding material comprising amorphous alloy soft magnetic particles, the filling rate of the amorphous alloy soft magnetic particles in the magnetic shielding material is 60 to 95 wt%, and the binder contains polyurethane. .

(2) Specific Structure of the Invention The soft magnetic powder used in the magnetic shielding agent of the present invention is composed of amorphous alloy soft magnetic particles.

The amorphous alloy soft magnetic particles used in the present invention generally have a flat shape and have an average thickness of 0.01 to 1 μm.

When the average thickness is less than 0.01 μm, when used as a magnetic shielding material, the dispersibility in a binder decreases, magnetic properties such as magnetic permeability deteriorate, and shielding properties decrease.

On the other hand, if the thickness exceeds 1 μm, a uniformly dispersed coating cannot be formed if the magnetic shielding material is thin, and the number of magnetic particles in the thickness direction of the magnetic shielding material is small, resulting in insufficient shielding properties. becomes.

In such a case, more preferable results will be obtained if the average thickness is 0.01 to 0.6 μm.

Note that the average thickness may be measured using an analytical scanning electron microscope.

Average aspect ratio (average outer diameter/average thickness) is 10 to 10
Preferably, 000 is used. If the average aspect ratio is less than 10, the influence of the demagnetizing field on the flat particles becomes large, resulting in a decrease in effective magnetic properties such as magnetic permeability, and a decrease in shielding properties.

On the other hand, if it is more than 10,000, it becomes difficult to produce powder with a small average outer diameter, resulting in poor moldability. In addition, more preferable results are obtained when the average aspect ratio is 10 to 500.

In this case, the average outer diameter is the particle size when the weight of the particle size determined by a particle size analyzer, which will be described later, is accumulated to 50% of the particle size, starting from the smallest particle size. It is also known as binding.

In the main surface shape of such a flat particle, its long axis (
When the maximum diameter) is a and the short axis (minimum diameter) is b, the average axial ratio a/b is preferably as large as possible, such as 1.2 or more, if directionality is required for the magnetic shield.

When the magnetic field source has directionality, by curing the magnetic paint while applying an orienting magnetic field in that direction, the magnetic permeability in that direction can be improved and the magnetic shielding effect can be increased. In this case, when a/b is 1.2 to 5, more preferable results are obtained.

The long axis and short axis of the particles may be measured using an analytical transmission electron microscope.

In the present invention, among these amorphous alloy soft magnetic particles, those having a particle size of 10 to 50 μm account for 35% of the total soft magnetic powder.
0.5 wt% or more of particles with a particle size exceeding 88 μm, and 1% of particles with a particle size of less than 3 μm.
It is preferably 0 wt% or less.

The particle size in this case is the average particle size measured with a particle size analyzer using a light scattering method.

More specifically, a particle size analyzer using a light scattering method measures the particle size distribution by measuring the scattering angle of Franhofer diffraction or Miy scattering using a laser beam, halogen lamp, etc. as a light source while circulating the sample. It is. The details can be found in, for example, “Powder and Industry J VOL, 19 No. 7 (
1987).

In the particle size distribution measured in this way, the particle size is 10~
If the particle diameter of 50 μm is less than 35% of the total soft magnetic powder, the dispersibility will be low when dispersed in a binder to form a magnetic shielding material, resulting in positional unevenness in the magnetic shielding effect, or Since the magnetic permeability decreases, the magnetic shielding effect becomes insufficient.

In such cases, particles with a particle size of 10 to 50 μm are used at 40W.
When the content is t% or more, especially 50wt% or more, more preferable results are obtained.

In addition, those with a particle size of 10 to 50 μm are usually 90 wt.
% or less.

In addition, those with a particle size exceeding 88 μm are 0. If it exceeds 5 wt%, it tends to cause uneven molding and positional unevenness in magnetic shielding characteristics.

In such cases, particles with a particle size exceeding 88 μm are
．． When it is 3 wt%, more preferable results are obtained.

Furthermore, it is preferable that 10 wt% or less of the particles have a particle size of less than 3 μm.

If it exceeds 10 wt%, the magnetic permeability decreases when dispersed in a binder to form a magnetic shielding material, and the magnetic shielding effect becomes insufficient.

In such cases, particles with a particle size of less than 3 μm are
%, more favorable results are obtained.

Such amorphous alloy soft magnetic particles are obtained by pulverizing ribbons, scales, sheets, and other shapes produced by a high-speed quenching method. As for the composition of the amorphous alloy used in the present invention, any alloy composition can be used, such as one consisting of a ferromagnetic transition metal and a metalloid, or one in which a small amount of other elements are added to these.
Ferromagnetic transition metals include Fe, Co, Ni, etc., especially F.
Those mainly composed of e, semimetals include B%S t, c,
It is mainly composed of p%Ge, especially B15t, and is preferably Fe-B-3ia element system. In addition, these components contain 10 at% or less of Cr % M n % M
o sNb, At, T is V s S n , Z
At least one kind such as n s Cu may be added.

Particularly in the case of Fe--B--Si alloys, those indicated by circles in FIG. 1 are amorphous soft magnetic alloys, and compositions in the range containing these can be used.

Note that FIG. 1 is a (Fe+M)-3i-B ternary composition diagram, and M will be described later.

The alloy composition in this case is preferably expressed by the following formula.

Formula Fe u MX (Si, B) W However, in the above formula, expressed in at%, x = O ~ 10
, preferably x=2-8, w=15-37, preferably w=18-30, u=100-(x+w).

And M is Ti, ■, Nb, Ta.

Cr%At least one selected from Mo, W, Mn, Co and Ni, among which Cr% is preferred in terms of corrosion resistance.
It is preferable that Cr be used alone or that Cr is essential and one or more other elements are included.

M is added to improve the corrosion resistance and brittleness of the alloy, but when the M content, that is, X exceeds 10, the saturation magnetic flux density decreases.

More specifically, when Cr is added, the amount added is preferably 2 to 10 at%; Nb, Mo, W, Ta,
1 f of V, Ti, Co, Ni, especially Nb, Mo, Ni
If more than ffi is added, the amount added is 1 to 10a.
t% is preferred.

By adding the amount within this range, corrosion resistance and brittleness are improved, and the saturation magnetic flux density is not reduced.

Further, W=15 to 37 is an amorphous formation region.

Among these composition ranges, points E, F, and G shown in Figure 1
, H in order is a region where a mechanically strong amorphous alloy is produced by the high-speed quenching method, so the grinding cost will be high in applications that require grinding as in the present invention. .

The present inventors conducted extensive tests on this ternary alloy and the above-mentioned substitutional alloys, and found that the lines connecting points E, F, G, and H outside these regions and points A, B, and C , D was found to be brittle and easily crushed.

To show this numerically, Fe+M in the triangular composition diagram in Figure 1,
B, Si coordinate point (Fe+M, B.

The preferred range expressed by Si) is A(63,32,5)
, B (62,23,15), C (63,15,22
), D (6B, 5.27), E (80,5,15)
, F (77, 7, 16), G (75, 13, 12), and H (77, 18, 5) in this order.
However, the numerical value is at%. The magnetic shielding properties of alloys obtained from this region were found to be satisfactory.

Additionally, alloys obtained from this region are sufficiently brittle. Brittleness is measured by forming an amorphous ribbon to a certain thickness and bending it around a rod with a diameter r, when the ribbon breaks.
When expressed as , O at the line E-F-G-H in Figure
Close to mm, and about 5 mm at line A-B-C-D
That's about it.

Such amorphous alloys can be manufactured by any conventionally known high-speed quenching method. An example of such a manufacturing method is described in Japanese Patent Publication No. 61-4302. For example, an ingot with a predetermined alloy composition is melted at high temperature, cooled at high speed by being blown against a rotating single steel roll, and the resulting ribbon or scale is coarsely ground into coarse particles. .

Coarse pulverization may be performed by any known method, and the average particle size is several microns.
A granular powder with a diameter of 50 .mu.m to about 50 .mu.m or a powder of similar size made by a known powder manufacturing method such as water atomization is used.

The rapidly quenched alloy is then subjected to a grinding process.

For pulverization, it is preferable to use a media stirring mill such as a pin type mill or a bead mill, particularly a pin type mill. The pin type mill is described in, for example, Japanese Patent Laid-Open No. 61-259739. A pin-type mill has a large number of pins installed on opposing surfaces of inner and outer cylinders, is filled with beads as a medium, and rotates the inner and outer cylinders at a relatively high speed.

When an amorphous alloy is pulverized with a pin-type mill, the particle size distribution described above can be easily obtained. Moreover, the average thickness of the amorphous alloy ribbon can be reduced to about 0.01 to 1 μm due to the strong shearing action of the pin-type mill.

Therefore, the shape of the obtained alloy particles is flat. When such flat grains are viewed from the surface direction, they do not have an amorphous shape but have a long axis. By pulverizing with a pin type mill, the average of a/b can be 1.2 or more, where a is the long sleeve and b is the short axis.

Note that the amorphous alloy particles obtained in this way are preferably subjected to heat treatment.

The heat treatment conditions may be any conditions as long as they can alleviate the distortion caused by pulverization, and are usually at 350 to 500°C for about 10 minutes to 5 hours.

The magnetic shielding material of the present invention contains soft magnetic powder made of such an amorphous soft magnetic alloy and a binder.

In the present invention, the filling rate of the soft magnetic powder in the magnetic shielding material is 60 to 95 wt%.

When the filling rate is less than 60 wt%, the magnetic shielding effect decreases rapidly, and when it exceeds 95 wt%, the soft magnetic powder cannot be firmly bound by the binder, and the strength of the magnetic shielding material decreases.

When the filling rate is 70 to 90 wt%, a particularly good magnetic shielding effect can be obtained, and the strength of the shielding material is also sufficient.

The binder used in the present invention contains polyurethane.

As the polyurethane, any condensation product of a polyvalent incyanate and a polyol compound can be used.

In this case, the polyvalent isocyanate includes 2.4-toluene diisocyanate, 2.6-toluene diisocyanate, 1.3-xylene diisocyanate, 1.4-xylene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p -phenylene diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate-1,4,4'-diphenylmethane diisocyanate, 3,3'-dimethylbiphenylene diisocyanate, 4,4'-biphenylene diisocyanate, hexamethylene Any of various polyvalent isocyanates such as diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and desmodur N is usable.

In addition, as polyol compounds, ethylene glycol, diethylene glycol, glycerin, trimethylolpropane, 1,4-butanediol, 1,6-hexanediol, pentaerythritol, sorbitol, neopentyl glycol, 1,4-cyclohexane dimetatool Any polyhydric alcohol can be used. In addition, polyester polyols produced by condensation polymerization of these polyhydric alcohols with polybasic acids such as phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, and sebacic acid, polyethylene glycol, polypropylene glycol, and polytetramethylene Polyether polyols such as glycols, various polyester polyols such as caprolactam, hydroxyl-containing acrylic esters, and hydroxyl-containing methacrylic esters can also be used.

The number average molecular weight of these polyurethanes is not particularly limited, but is usually about 5,000 to 100,000.

The binder used in the present invention may consist only of such polyurethane, or may be used in combination with other thermoplastic resins shown below.

(1) Vinyl chloride copolymer Vinyl chloride-vinyl acetate-vinyl alcohol copolymer, vinyl chloride-vinyl alcohol copolymer, vinyl chloride-vinyl alcohol-vinyl propionate copolymer, vinyl chloride-vinyl acetate-malein Acid copolymer, vinyl chloride-vinyl acetate-vinyl alcohol-maleic acid copolymer, vinyl chloride-vinyl acetate-terminated OHflll mB alkyl group type polymer, such as VROH, VYNC manufactured by UCC.

VYEGX%VERR, VYES, VMCA.

VAGH, UCARMAG520, UCARMAG52
Examples include 8th grade.

These may contain carboxylic acids.

(2) Polyester resin Saturated polybasic acids such as phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, and sebacic acid, and ethylene glycol, diethylene glycol, glycerin, trimethylolpropane, 1.2 propylene glycol,
Esters with polyhydric alcohols such as 1.3-butanediol, dipropylene glycol, 1.4-butanediol, 1.6-hexanediol, pentaerythritol, sorbitol, glycerin, neopentyl glycol, 1.4-cyclohexane dimetatool. Saturated polyester resins obtained by bonding or these polyester resins are
An example is a resin modified with O3Na or the like (eg, Vylon 53S).

(3) Polyvinyl alcohol resins Examples include polyvinyl alcohol, butyral resins, acetal resins, formal resins, and copolymers of these components.

(4) Epoxy resin, phenoxy resin Epoxy resin produced by the reaction of bisphenol A with epichlorohydrin or methyl epichlorohydrin, such as manufactured by Shell Chemical (Epicort 152.154.828.1001.1004.
1007), manufactured by Dow Chemical (DE N431,
DER732, DER511, DER331)
, manufactured by Dainippon Ink (Epicron 400.800), phenoxy resin manufactured by UCC (PKHA% PKHC, PKHH), which is a high polymerization degree resin of the above epoxy, a copolymer of brominated bisphenol A and epichlorohydrin,
Manufactured by Dainippon Ink and Chemicals (Epicron 145.152.
153.1120), and these also include those containing a carboxylic acid group.

(5) Various cellulose derivatives can be used, but particularly effective ones include nitrified cotton, cellulose acetobutyrate, ethyl cellulose, butyl cellulose, and acetyl cellulose.

In addition, polyfunctional polyester resins, polyether ester resins, polyvinylpyrrolidone resins and derivatives (pv
Also effective are acrylic resins containing at least one of p-olefin copolymers), polyamide resins, polyimide resins, phenol resins, spiroacetal resins, acrylic esters and methacrylic esters containing hydroxyl groups as polymerization components.

Examples of elastomers, prepolymers and oligomers are listed below.

(1) Acrylonitrile-butadiene copolymer elastomer An acrylonitrile-butadiene copolymer prepolymer having a terminal hydroxyl group, commercially available as PolyBD Retired Resin manufactured by Sinclair Petrochemical, or an elastomer such as Hiker 1432 J manufactured by Nippon Zeon.

(2) Polybutadiene Elastomer A prepolymer having a low molecular weight terminal hydroxyl group, such as PolyBD Retired Resin R-15 manufactured by Sinclair Vetrochemical Co., is particularly suitable from the viewpoint of compatibility with thermoplastic resins.

Also, polybutadiene cyclized products, Japanese synthetic rubber group CBR-
M901 also has excellent properties when combined with thermoplastic resin.

Other suitable thermoplastic elastomer and prepolymer systems include styrene-butadiene rubber, chlorinated rubber, acrylic rubber, isoprene rubber and its cyclized product (Japanese Synthetic Rubber Group ClR701), epoxy-modified rubber, internal plastic Elastomers such as saturated linear polyester (Toyobo Vylon #300) can also be effectively used.

Note that the content of these resins used in combination with polyurethane is preferably 80 wt% or less in the binder.

The magnetic shielding material of the present invention usually further contains the above-mentioned polyvalent isocyanate having one NGO group as a curing agent. The amount of the curing agent is about 5 to 30 wt% based on the binder.

In addition, the magnetic shielding material may contain a dispersant, a stabilizer, a coupling agent, etc. in addition to the soft magnetic powder, binder, and hardening agent.

Such a magnetic shielding material is usually used after being made into a molding or coating composition using a necessary solvent, molded into a desired shape, and heat-cured.

In addition, curing is generally performed in a heating oven at 50 to 80°C.
What is necessary is just to heat it for 6 to 10 hours.

When the magnetic shielding material of the present invention is formed into a film or a thin plate and used for magnetic shielding, the thickness of the magnetic shielding material is preferably 5 to 200 μm.

This is because the magnetic shielding material of the present invention contains soft magnetic powder at the filling rate as described above, so it exhibits a uniform magnetic shielding effect even at a thickness of 5 μm, and the shielding material can withstand a magnetic field strong enough to prevent magnetic saturation. This is because even if the shield is formed to have a thickness exceeding 200 μm, the magnetic shielding effect will not be significantly improved, and a thickness of 200 μm or less is advantageous in terms of cost.

In addition, when the magnetic shielding material of the present invention is molded or coated into a desired shape, it can be made into a highly directional magnetic shielding material by applying an oriented stone n field or mechanically orienting it. When formed in the form of a plate or a film, it has a high magnetic shielding effect against magnetic fields in a direction parallel to the film surface, and exhibits a sufficient effect within the above thickness range.

■Specific Effects of the Invention The magnetic shielding material of the present invention contains soft magnetic powder made of amorphous alloy soft magnetic particles having a predetermined average thickness and aspect ratio at a filling rate within a predetermined range, and a binder containing polyurethane. Contains.

Therefore, the magnetic shielding effect is high, and when the magnetic shielding material is in the form of a plate or film, the desired effect can be obtained with a thickness of about 5 to 200 μm, especially against magnetic fields in the direction parallel to the film surface. Moreover, even in such a case, since the strength of the magnetic shielding material is high, the magnetic shielding material can be applied in a wide range of applications, including magnetic shielding for speakers, CRTs, etc., and the cost can be reduced.

■Specific embodiments of the invention Hereinafter, the present invention will be explained in detail by giving examples.

[Example 1] An amorphous soft magnetic alloy having the composition shown in Table 1 below was ground in a moving ball mill to obtain coarse powder with an average particle size of 32 μm, and this was ground in a bottle-shaped mill to obtain soft magnetic powder for magnetic shielding. A sample was prepared.

Note that the grinding conditions in the pin type mill are shown in Table 1.

Further, Table 1 shows the properties of each sample.

However, in Table 1, A1 Amount of powder with particle size 10-50 μm B: Amount of powder with particle size exceeding 88 μm C: Amount of powder with a particle size of less than 3 μm It is.

Note that the average thickness was measured using an analytical scanning electron microscope, and the average outer diameter was measured using a particle size analyzer.

The soft magnetic powder sample thus obtained was mixed with the following binder, curing agent, and solvent to prepare a magnetic shielding material sample.

(Binder) Vinyl chloride-vinyl acetate copolymer [S-LEC A (manufactured by Block Chemical Co., Ltd.)] 1100 parts by weight Polyurethane Niraporan 2304 (manufactured by Nippon Polyurethane Co., Ltd.)] 11
00 parts by weight solid content) (Curing agent) Polyisocyanate [Coronate HL (manufactured by Nippon Polyurethane Co., Ltd.)] 110 parts by weight Solvent) MEK 850 parts by weight The filling rate of soft magnetic powder in the magnetic shielding material sample is also listed in Table 1. do.

These magnetic shielding materials were coated to a thickness of 100 μm on a PUT substrate having a thickness of 75 μm, and were cured by heating at 60° C. for 60 minutes to obtain shield plate samples.

The shield ratio was measured for these shield plate samples.

Note that the shield ratio is expressed as a relative value with sample No. 9 as 1.

The results are shown in Table 1.

The shielding ratio is determined by placing a shielding plate sample on a magnet, measuring the leakage magnetic flux φ at a position 0.5 cm from the shielding plate sample, and calculating the magnetic flux φ when there is no shielding plate. The ratio φ/φ compared with It is.

In addition, a bending test was performed on the above shield plate sample, and cracks in the magnetic shield material or peeling from the PUT substrate were observed.

In this test, the shield plate sample was bent by 180 degrees so that the PET substrate was on the inside.

Evaluation: × for those with cracks or peeling, O for those without
And so.

The effects of the present invention are clear from the above examples.

[Brief explanation of the drawing]

FIG. 1 is a ternary diagram showing the composition of an amorphous alloy. Patent applicant TDC Co., Ltd. Tokyo Magnetic Printing Co., Ltd.FIG, IFe+M 3 (at%)

Claims (2)

[Claims] (1) A magnetic shielding material containing soft magnetic powder and a binder, wherein the soft magnetic powder is an amorphous alloy soft material with an average thickness of 0.01 to 1 μm and an average outer diameter/average thickness ratio of 10 to 10,000. A magnetic shielding material comprising magnetic particles, wherein the filling rate of the amorphous alloy soft magnetic particles in the magnetic shielding material is 60 to 95 wt%, and the binder contains polyurethane. (2) Among the amorphous alloy soft magnetic particles, 3 amorphous alloy soft magnetic particles having a particle size of 10 to 50 μm are used.
5 wt% or more of amorphous alloy soft magnetic particles with a particle size exceeding 88 μm is 0.5 wt% or less, and the amorphous alloy soft magnetic particles with a particle size of less than 3 μm are 1
The magnetic shielding material according to claim 1, which has a content of 0 wt% or less.