JPH0834357B2 - Magnetic shield material - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft magnetic powder for magnetic shield and a magnetic shield material using the same, and particularly to a flat amorphous alloy soft alloy having a large shield effect against a magnetic field in a specific direction. The present invention relates to a magnetic shield material using a soft magnetic powder for magnetic shield composed of magnetic particles.

Prior Art and Its Problems Magnetic shield materials are used to prevent magnetized objects and other magnetic field sources from affecting other objects and electric circuits. A metal plate having a high magnetic permeability is desirable for the magnetic shield material from the viewpoint of the shielding property, but its use is extremely limited. In the case of a powder material, it can be used in various ways, such as dispersing it in an organic binder and applying it in the form of paint to the required parts of the shield, or applying it to a suitable flexible support etc. to form a shield plate. It is possible because it is possible.

Various proposals have been made for magnetic shield materials using powder of high magnetic permeability. For example, JP-A-58-59268 discloses a magnetic shield coating in which flat powder of a high magnetic permeability alloy is mixed in a polymer compound binder, and JP-A-59-201493 discloses a flat powder obtained by pulverizing a soft magnetic amorphous alloy. Shown is a magnetic shield coating in which the powder is mixed in a polymeric binder.

The magnetic shield material using these flat powders has isotropic shield characteristics between planes perpendicular to the thickness direction. Further, alloy flat powder as shown in JP-A-59-201493,
A powder obtained by crushing a ribbon rapidly cooled by bringing a transition metal-metalloid (metalloid) alloy into contact with the surface of a chill roll from a high temperature molten state is used, but the lower limit of the thickness of the ribbon is
It is 10 μm, and normally only about 10 to 50 μm can be obtained, and even if it is crushed and scale-like powder, the thickness of the powder does not change. The characteristics are very poor. Although the magnetic properties of the amorphous alloy itself are very good, the magnetic properties are not fully utilized in such a flaky powder.

Japanese Patent Application Laid-Open No. 58-197205 discloses one example of a method of crushing a rapidly quenched alloy into flakes. However, the crushing method is a conventionally known stamp mill, dry ball mill,
Either a wet ball mill, an attritor, or a vibration mill is used. Further, in JP-A-60-401, a sheet,
Ribbon, tape, and wire-shaped rapid-quenching amorphous alloy are embrittled at a temperature below the glass transition point and then pulverized.The means used are rod mill, ball mill, impact mill, disc mill, stamp mill, crusher. It is a roll. However, these pulverizing means cannot pulverize the sheet, ribbon, etc. to the minimum thickness or less, and only give 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 it lacks magnetic uniformity and causes a large leakage of the magnetic field.

The magnetic field to be shielded by the magnetic shield may be isotropic, but it is often strong in a specific direction.In such a case, we would like to design a particularly large magnetic shielding effect in this specific direction. Even if magnetic orientation is applied during coating using powder, there is almost no effect.

In order to solve such a problem, the present inventors have
In Japanese Patent Application No. 62-215857, the average thickness of powder and the average outer diameter /
By defining the average thickness ratio, we have proposed a magnetic shield material that has a high shielding effect and is uniform. Compared with conventional powders, this material has improved magnetic shielding effect in the direction parallel to the film surface even when it is made thin, but the requirements for magnetic shielding are strict, and more effective magnetic shielding materials are required. .

II OBJECT OF THE INVENTION It is an object of the present invention to provide a magnetic shield having a high magnetic shield property in a direction parallel to the film surface even when it is made thin and has high strength.

III Disclosure of the Invention Such an object is achieved by the present invention described below.

That is, the present invention is a magnetic shield material containing a soft magnetic powder and a binder, wherein the soft magnetic powder is an amorphous alloy having an average thickness of 0.01 to 1 μm and an average outer diameter / average thickness ratio of 10 to 10000. It consists of soft magnetic particles, and the filling ratio of these amorphous alloy soft magnetic particles in the magnetic shield material is 60 to 95.
wt%, and the composition of the amorphous alloy soft magnetic particles is represented by the formula Fe _u M _x (Si, B) _w (in the above formula, M is Cr, or Cr and Ti, V,
At least one selected from Nb, Ta, Mo, W, Mn, Co and Ni, and represented by at%, x = 2 to 10 (however, the content of Cr is 2 to 10 at%), w = 15-37, u = 100
-(X + w). ), And the binder contains polyurethane, which is a magnetic shield material.

IV Specific Structure of the Invention The soft magnetic powder used in the magnetic shield agent of the present invention is composed of amorphous alloy soft magnetic particles.

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

If the average thickness is less than 0.01 μm, the dispersibility in the binder when used as a magnetic shield material is deteriorated, magnetic properties such as magnetic permeability are deteriorated, and the shield property is deteriorated.

On the other hand, if it exceeds 1 μm, a uniformly dispersed coating film cannot be formed when the thickness of the magnetic shield material is thin, and the number of magnetic particles in the thickness direction of the magnetic shield material is small, resulting in insufficient shield characteristics. Becomes

In such a case, more preferable results are obtained when the average thickness is 0.01 to 0.6 μm.

The average thickness may be measured with an analytical scanning electron microscope.

Average aspect ratio (average outer diameter / average thickness) is 10 to 1000
It is preferable to use 0. If the average aspect ratio is less than 10, the influence of the demagnetizing field on the flat particles becomes large, the effective magnetic characteristics such as magnetic permeability deteriorate, and the shield characteristics deteriorate.

On the other hand, if it is 10,000 or more, it becomes difficult to produce a powder having a small average outer diameter, and thus the moldability is deteriorated. A more preferable result is obtained when the average aspect ratio is 10 to 500.

The average outer diameter in this case is a particle size when the particle size obtained by the particle size analyzer described below is 50% by cumulative weight from the smaller particle size, and this is D _50. Are known.

In the main surface shape of such flat particles, when the major axis (maximum diameter) is a and the minor axis (minimum diameter) is b, the average a / b of the axial ratios requires the directionality of the magnetic shield. If this is the case, a maximum value of 1.2 or higher is desirable. When the magnetic field source has a directional property, the magnetic permeability in that direction can be improved by curing the magnetic paint while applying the orientation magnetic field in that direction, and the magnetic shield effect can be enhanced. In this case, more preferable results are obtained when a / b is 1.2 to 5.

The major axis and the minor axis of the particles may be measured with an analytical transmission electron microscope.

In the present invention, the amorphous alloy soft magnetic particles having a particle size of 10 to 50 μm account for 35 wt% of the entire soft magnetic powder.
0.5 wt% if the particle size exceeds 88 μm
It is below, and it is preferable that the particles having a particle size of less than 3 μm are below 10 wt%.

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

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

In the particle size distribution measured in this way, the particle size of 10 ~
If the content of 50 μm is less than 35 wt% of the whole soft magnetic powder, the dispersibility is low when dispersed in a binder to form a magnetic shield material, and the magnetic shield effect has positional unevenness or magnetic permeability. , The magnetic shield effect becomes insufficient.

In such a case, more preferable results are obtained when the particle diameter of 10 to 50 μm is 40 wt% or more, particularly 50 wt% or more.

The particles having a particle size of 10 to 50 μm are usually 90 wt% or less.

Further, if the particle size exceeds 88 μm and exceeds 0.5 wt%, uneven molding is likely to occur and positional unevenness of the magnetic shield characteristics is likely to occur.

In such a case, the particle size exceeding 88 μm is 0 to 0.
When it is 3 wt%, more preferable results are obtained.

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

If it exceeds 10 wt%, the magnetic permeability will decrease when dispersed in a binder to form a magnetic shield material, and the magnetic shield effect will be insufficient.

In such a case, the particle size of less than 3 μm is 0 to 7 wt.
%, More preferable results are obtained.

Such amorphous alloy soft magnetic particles are obtained by pulverizing ribbons, scales, sheets and other shapes produced by the rapid quenching method. As the composition of the amorphous alloy used in the present invention, any alloy composition such as a ferromagnetic transition metal and a semimetal, or a composition in which a small amount of another element is further added can be used. Ferromagnetic transition metals such as Fe, Co, and Ni, especially those mainly composed of Fe, semimetals such as B, Si, or C and
P, Ge added, especially B, Si as the main component, Fe-B-
Si _{3 element} system. And C of 10at% or less in these ingredients
r, or Cr and Mn, Mo, Nb, Al, Ti, V, Sn, Zn, Cu
And at least one of the above.

Particularly in the case of Fe-B-Si based alloys, the ones indicated by ◯ in FIG. 1 are amorphous soft magnetic alloys, and the composition in the region containing them can be used.

FIG. 1 is a (Fe + M) -Si-B3 elemental composition diagram, and M will be described later.

In this case, the alloy composition is preferably represented by the following formula.

Formula FeM _x (Si, B) _w However, in the above formula, x = 2
10, preferably x = 2-8, w = 15-37, preferably w
= 18-30, u = 100- (x + w).

And M is Ti, V, Nb, Ta, Cr, Mo, W, Mn, Co
At least one selected from Ni and Ni is used, but in terms of high corrosion resistance and easy flattening, only Cr or Cr is essential and contains at least one other.

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

More specifically, the addition amount of Cr is 2 to 10 at%,
Nb, Mo, W, Ta, V, Ti, Co, Ni, especially Nb, Mo, Ni 1
The addition amount of the seeds or more is preferably 1 at% or more and less than 10 at%.

By setting the addition amount in such a range, corrosion resistance and brittleness are improved, and the saturation magnetic flux density is not lowered.

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

Of such composition ranges, points E, F, and
The part above the line connecting G and H in order is a region where a mechanically tough amorphous alloy is produced by the rapid quenching method, so that the crushing cost is high in the application requiring crushing as in the present invention. Become.

The inventors of the present invention have conducted extensive tests on the ternary alloy and the substitutional alloys as described above. As a result, the line connecting points E, F, G, and H and the points A, B, and C outside the region. , D
It was found that the amorphous alloy in the area between the line connecting the two was brittle and easily crushed.

This is shown numerically, Fe + M in the triangular composition diagram of Fig. 1,
Preferred ranges represented by the coordinate points of B and Si (Fe + M, B, Si) are A (63, 32, 5), B (62, 23, 15), C (63,
15, 22), D (68, 5, 27), E (80, 5, 15), F
(77, 7, 16), G (75, 13, 12), and H (77, 18,
It is within the range in which 5) is connected in order. However, the value is at%. The magnetic shielding properties of the alloys obtained from this region have been found to be satisfactory.

Also, the alloys obtained from this region are sufficiently brittle. The brittleness is r when the amorphous ribbon is formed to have a constant thickness and the ribbon is broken when it is bent around a rod of diameter r.
When expressed by, 0 m at the line E-F-G-H in FIG.
It is close to m and is about 5 mm at the line ABCD.

Such an amorphous alloy can be manufactured by any conventionally known rapid quenching method. An example of such a manufacturing method is described in Japanese Patent Publication No. 61-4302. For example, an ingot of a predetermined alloy composition is melted at a high temperature, sprayed on a rotating steel single roll or the like and rapidly cooled, and the obtained ribbon or scale is coarsely crushed to obtain coarse particles. .

The coarse pulverization may be carried out by any known method, and a granular powder having an average particle diameter of several μm to about 50 μm or a powder of the same size produced by a known powder manufacturing method such as a water atomizing method is used.

 The fast-quenched alloy is then subjected to a grinding process.

Grinding is performed with a medium stirring mill such as a pin type mill or a bead mill,
It is particularly preferable to use a pin type mill. The pin type mill is described, for example, in JP-A-61-259739. In the pin type mill, a large number of pins are erected on the opposing surfaces of the inner and outer cylinders, beads are filled as a medium, and the inner and outer cylinders are rotated at a relatively high speed.

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

Therefore, the shape of the obtained alloy particles is a flat body. When such flat particles are viewed from the surface direction, they show a particle shape having a long axis rather than an indefinite shape. By crushing with a pin-type mill, the average of a / b can be 1.2 or more when the major axis is a and the minor axis is b.

The amorphous alloy particles thus obtained are
It is preferably subjected to heat treatment.

The heat treatment conditions may be such that strain due to pulverization can be relaxed, and it is usually about 10 minutes to 5 hours at 350 to 500 ° C.

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

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

If the filling ratio is less than 60 wt%, the magnetic shielding effect is sharply reduced, and if 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 shield effect is obtained, and the strength of the shield material is sufficient.

 The binder used in the present invention contains polyurethane.

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

In this case, as the polyvalent isocyanate, 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, 4,4'-diphenylmethane diisocyanate, 3,3'-dimethylbiphenylene diisocyanate, 4,4'-biphenylene diisocyanate, hexamethylylene diisocyanate, iso Any of various polyisocyanates such as phorone diisocyanate, dicyclohexylmethane diisocyanate, Desmodur L, and Desmodur N can be used. Further, as the polyol compound, ethylene glycol, diethylene glycol, glycerin, trimethylolpropane, 1,4
-Butanediol, 1,6-hexanediol, pentaerythritol, sorbitol, neopentyl glycol,
Any polyhydric alcohol such as 1,4-cyclohexanedimethanol can be used. In addition to these polyhydric alcohols, phthalic acid, isophthalic acid, terephthalic acid,
Polyester polyol by polycondensation with polybasic acid such as succinic acid, adipic acid, sebacic acid, polyether polyol such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, caprolactam, hydroxyl-containing acrylate ester, hydroxyl-containing Various polyester polyols such as methacrylic acid ester 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 be made of only 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-maleic acid copolymer, vinyl chloride-vinyl acetate-vinyl alcohol-maleic acid copolymer, vinyl chloride-vinyl acetate-terminal OH side chain Alkyl group copolymer, for example V manufactured by UCC
ROH, VYNC, VYEGX, VERR, VYES, VMCA, VAGH, UCARMAG5
20, UCARMAG 528 and the like.

 These may contain carboxylic acids.

(2) Polyester resin phthalic acid, isophthalic acid, terephthalic acid, succinic acid,
Saturated polybasic acids such as adipic acid and sebacic acid, ethylene glycol, diethylene glycol, glycerin,
Trimethylolpropane, 1,2 propylene glycol,
Ester bond with polyhydric alcohols such as 1,3 butanediol, dipropylene glycol, 1,4 butanediol, 1,6 hexanediol, pentaerythritol, sorbitol, glycerin, neopentyl glycol, 1,4 cyclohexanedimethanol Examples thereof include the saturated polyester resin obtained by the method described above or a resin obtained by modifying these polyester resins with SO ₃ Na or the like (for example, Vylon 53S).

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

(4) Epoxy resin, phenoxy resin Epoxy resin obtained by reaction of bisphenol A with epichlorohydrin, methyl epichlorohydrin, for example, Shell Chemical (Epicoat 152, 154, 828, 1001, 1004, 100
7), made by Dow Chemical (DEN431, DER732, DER511, DER33
1), made by Dainippon Ink (Epiclon 400, 800), and phenoxy resin (PKHA, PKHC, PKHH) made by UCC, which is a high-polymerization resin of the above epoxy, a copolymer of brominated bisphenol A and epichlorohydrin, large Products manufactured by Nippon Ink Chemical Co., Ltd. (Epiclon 145, 152, 153, 1120) are available, and those containing a carboxylic acid group are also included.

(5) Fibrin derivatives Various types are used, but particularly effective ones are nitrification cotton, cellulose acetobutyrate, ethyl cellulose,
Butyl cellulose, acetyl cellulose and the like are preferable.

In addition, polyfunctional polyester resins, polyetherester resins, polyvinylpyrrolidone resins and derivatives (PV
P-olefin copolymers), polyamide resins, polyimide resins, phenol resins, spiroacetal resins, acrylic resins containing at least one hydroxyl group-containing acrylic ester and methacrylic ester as polymerization components are also effective.

Examples of the elastomer, prepolymer or oligomer will be given below.

(1) Acrylonitrile-butadiene copolymerized elastomer Acrylonitrile butadiene copolymer prepolymer having a terminal hydroxyl group, which is commercially available as poly BD retied resin manufactured by Sinclair Petrochemical Co., Ltd., or an elastomer such as Hiker 1432J manufactured by Nippon Zeon.

(2) Polybutadiene Elastomer A prepolymer having a low molecular weight terminal hydroxyl group such as Porin BD Retied Resin R-15 manufactured by Sinclair Petrochemical Co., Ltd. is particularly preferable in terms of compatibility with a thermoplastic resin.

Also cyclized polybutadiene, CBR-M made by Japan Synthetic Rubber
901 also has excellent properties when combined with a thermoplastic resin.

Other suitable thermoplastic elastomers and their prepolymer systems include styrene-butadiene rubber, chlorinated rubber, acrylic rubber, isoprene rubber and cyclized products thereof (Japan Synthetic Rubber ICR701), epoxy-modified rubber, internal Elastomers such as plasticized saturated linear polyester (Toyobo Byron # 300) can also be effectively used.

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

The magnetic shield material of the present invention usually further contains the above-mentioned polyvalent isocyanate having a —NCO group as a curing agent. The curing agent is about 5 to 30 wt% with respect to the binder.

The magnetic shield material may contain a dispersant, a stabilizer, a coupling agent and the like in addition to the soft magnetic powder, the binder and the curing agent.

Such a magnetic shield material is usually formed into a desired shape after being formed into a composition for molding or coating using a necessary solvent, and then heat-cured before use.

The curing may be generally carried out by heating in a heating oven at 50 to 80 ° C. for 6 to 100 hours.

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

This is because the magnetic shield material of the present invention contains the soft magnetic powder at the filling rate as described above, and shows a uniform magnetic shield effect even with a thickness of 5 μm, and the magnetic field strength is such that the shield material is not magnetically saturated. This is because the magnetic shield effect is not significantly improved even if the shield is formed to have a thickness of more than 200 μm, and if the thickness is 200 μm or less, it is advantageous in cost.

Incidentally, when the magnetic shield material of the present invention is molded or applied in a required shape, by applying an orienting magnetic field or by mechanically orienting it, a magnetic shield material having a high directional property can be obtained. When formed into a film shape or a film shape, it has a high magnetic shield effect against a magnetic field in a direction parallel to the film surface, and exhibits a sufficient effect in the above thickness range.

V. Specific Effect of the Invention The magnetic shield material of the present invention contains a binder containing a soft magnetic powder made of amorphous alloy soft magnetic particles having a predetermined average thickness and an aspect ratio in a predetermined filling rate and containing polyurethane. Contains.

Therefore, the magnetic shield effect is high, and when the magnetic shield material is formed into a plate shape or a film shape, a desired effect can be obtained with a thickness of about 5 to 200 μm particularly for a magnetic field in a direction parallel to the film surface. In addition, since the strength of the magnetic shield material is high even in such a case, it can be applied to a wide range of applications in addition to the magnetic shield of a speaker, a CRT, etc., and the cost can be reduced.

VI Specific Examples of the Invention Hereinafter, the present invention will be described in detail with reference to Examples.

Example 1 Amorphous soft magnetic alloy having the composition shown in Table 1 below was crushed with a vibrating ball mill to obtain coarse powder having an average particle diameter of 32 μm, which was crushed with a pin type mill to obtain a soft magnetic powder sample for magnetic shield. Was produced.

 Table 1 shows the crushing conditions in the pin type mill.

 Table 1 shows the properties of each sample.

 However, in Table 1, A: the amount of powder having a particle size of 10 to 50 μm, B: the amount of powder having a particle size of more than 88 μm, C: the amount of powder having a particle size of less than 3 μm.

The average thickness was measured with an analytical scanning electron microscope, and the average outer diameter was measured with 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 shield material sample.

(Binder) Vinyl chloride-vinyl acetate copolymer [S-REC A
(Sekisui Chemical Co., Ltd.)] 100 parts by weight Polyurethane [Nipporan 2304 (manufactured by Nippon Polyurethane Company)] 100 parts by weight (solid content conversion) (Curing agent) Polyisocyanate [Coronate HL (manufactured by Nippon Polyurethane Company)] 10 parts by weight (solvent ) MEK 850 parts by weight Table 1 also shows the filling factor of the soft magnetic powder in the magnetic shield material sample.

These magnetic shielding materials are applied to a 75μm thick PET substrate.
It was applied to a thickness of 00 μm and cured by heating at 60 ° C. for 60 minutes to obtain a shield plate sample.

The shield ratio was measured for these shield plate samples.

The shield ratio was expressed as a relative value with sample No. 9 set to 1.

 Table 1 shows the results.

The shield ratio is measured by setting the shield plate sample on the magnet and measuring the leakage magnetic flux φ at the 0.5 cm position from the shield plate sample, and the magnetic flux φ when there is no shield plate.
_The ratio φ / φ ₀ compared with ₀ .

In addition, a bending test was performed on the above-mentioned shield plate sample to observe cracks in the magnetic shield material or peeling from the PET substrate.

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

In the evaluation, those with cracks or peeling were evaluated as x, and those without cracks were evaluated as o.

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

The amorphous alloy having the composition of the present invention could be crushed in about 7 to 11 hours.

[Brief description of drawings]

 FIG. 1 is a ternary diagram showing the composition of an amorphous alloy.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hirosumi Shimizu 1-13-1 Nihonbashi, Chuo-ku, Tokyo Inside TDK Corporation (72) Inventor Ichiho Hirai 1-1-13-1 Nihonbashi, Chuo-ku, Tokyo -D-K Co., Ltd. (72) Inventor Ryohei Mimura 1-5-1, Taito, Taito-ku, Tokyo Tokyo Magnetic Printing Co., Ltd. (72) Inventor Atsushi Makimura 1-1-5, Taito, Taito-ku, Tokyo Tokyo Magnetic Within Printing Co., Ltd. (72) Inventor Hiroshi Hosaka 1-5-1 Taito, Taito-ku, Tokyo Inside Tokyo Magnetic Printing Co., Ltd.

Claims (2)

[Claims] 1. A magnetic shield material containing soft magnetic powder and a binder, wherein the soft magnetic powder has an average thickness of 0.01-1.
μm, the average outer diameter / average thickness ratio is 10 to 10000, and the filling ratio of the amorphous alloy soft magnetic particles in the magnetic shield material is 60 to 95 wt%. The composition of the particles is represented by the formula Fe _u M _x (Si, B) _w (in the above formula, M is Cr, or Cr and Ti, V,
At least one selected from Nb, Ta, Mo, W, Mn, Co and Ni, and represented by at%, x = 2 to 10 (however, the content of Cr is 2 to 10 at%), w = 15-37, u = 100
-(X + w). ), Wherein the binder contains polyurethane. 2. Among the amorphous alloy soft magnetic particles,
Amorphous alloy soft magnetic particles with a particle size of 10-50 μm
Amorphous alloy soft magnetic particles with a particle size of 35 wt% or more and a particle size exceeding 88 μm are 0.5 wt% or less and a particle size is 3 μm.
The magnetic shield material according to claim 1, wherein the amorphous alloy soft magnetic particles having a particle size of less than m is 10 wt% or less.