JPH0834356B2 - Magnetic shield material - Google Patents

Description

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

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 powdered materials, this can be dispersed in an organic binder and applied in the form of paint to the required parts of the shield, or applied to a suitable flexible support, etc. to form a shield plate for various uses. This is convenient 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,
Although a powder obtained by crushing a ribbon which is obtained by bringing a transition metal-metalloid (metalloid) -based alloy into contact with the surface of a cooling roll from a high temperature molten state and rapidly quenching is used, the lower limit of the thickness of the ribbon is 10 μm. Usually, only about 10 to 50 μm can be obtained. Even if crushed and scale-like powder is used, the thickness of the powder does not change. Bad for

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 the conventional powder, this material has an improved magnetic shield effect in the direction parallel to the film surface even when it is made thin, but the requirements for the magnetic shield are strict, and a magnetic shield material having a higher effect is required.

II Object of the Invention An object of the present invention is to provide a magnetic shield material having a good magnetic shield property in a direction parallel to the film surface even if it is thinned.

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 has an average thickness of 0.
It is composed of amorphous alloy soft magnetic particles having an average outer diameter / average thickness of 10 to 10000 and a composition of the amorphous alloy soft magnetic particles of the formula Fe _u M _x (Si, B) _w (where M is , Cr, or Cr, 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). ), The maximum magnetic permeability in a DC magnetic field is 15 to 70, and the coercive force is 5 to 20 (O
e) A magnetic shield material characterized in that

IV Specific Structure of the Invention The soft magnetic powder used in the magnetic shield material 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 the thickness 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 shielding characteristics. .

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 directionality, curing the magnetic paint while applying an orientation magnetic field in that direction can improve the magnetic susceptibility in that direction and increase the magnetic shield effect. 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.

Further, the soft magnetic powder composed of such soft magnetic particles,
It is preferable to have the following magnetic characteristics in order to improve the magnetic shield characteristics.

Assuming that the maximum magnetic permeability in a DC magnetic field is μ _m and the coercive force is Hc, 20 ≦ μ _m ≦ 50, more preferably 25 ≦ μ _m ≦ 40, 2 ≦
Hc ≦ 13, more preferably 3 ≦ Hc ≦ 10.

Such soft magnetic particles of amorphous alloy 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, mainly Fe, and semimetals such as B, Si or C,
P- and Ge-added materials, especially Fe-B-, mainly B and Si
Si3 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 Fe _u M _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 (r or Cr and Ti, V, Nb, Ta, Mo,
At least one selected from W, Mn, Co, and Ni, but in view of high corrosion resistance and easy flattening, only Cr or one or more of other Cr is essential.

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

More specifically, when Cr is added, the addition amount is 2 to 10 at%, and Nb, Mo, W, Ta, V, Ti, Co, N
When i, particularly one or more of Nb, Mo and Ni is added, the addition amount is preferably 1 at% or 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 upper part of 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,
The preferred range represented by the coordinate points of B and Si (Fe + M, B, Si) is A (63, 62, 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, 5) are connected in this order. However, the value is at%. The magnetic shielding properties of the alloys obtained from this region have been found to be satisfactory.

The alloys obtained from this region are also 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, the medium is filled with beads, 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 preferably heat-treated in order to improve the magnetic properties. As a result, the magnetic shield material having the magnetic characteristics described later can be obtained well.

The heat treatment condition is usually at 350 to 500 ° C. for about 10 minutes to 5 hours. Further, the heat treatment is preferably carried out in an atmosphere of an inert gas such as N ₂ or Ar, but it may be carried out in air or in a reducing atmosphere which does not use H ₂ . The magnetic shield material of the present invention contains a soft magnetic powder made of such an amorphous soft magnetic alloy and a binder.

The magnetic shield material of the present invention has a maximum magnetic permeability of μ _m in a DC magnetic field and a coercive force of Hc of 15 ≦ μ _m ≦ 70.
(Oe) ≦ Hc ≦ 20 (Oe).

magnetic shielding effect and mu _m is less than 15 is insufficient. In addition, the particles exceeding 70 make the particles large and the uniformity of the film deteriorates, and the shielding effect also deteriorates.

When Hc exceeds 20 (Oe), the magnetic shield effect becomes insufficient, and when it is less than 5 (Oe), the particles become large and the film uniformity deteriorates in the same manner as above, and the shielding effect also decreases. To do.

Note that 18 ≦ μ _m ≦ 60, especially 25 ≦ μ _m ≦ 60, 7 (Oe)
Even better results are obtained when ≦ Hc ≦ 18 (Oe), particularly 7 ≦ Hc ≦ 15.

Further, in the present invention, the filling rate in the magnetic shield material of soft magnetic powder is preferably 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 preferably 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 , Hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, Desmodur L, Desmodur N and the like 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 Various polyester polyols such as contained 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,
1,3 butanediol, dipropyglycol, 1,4 butanediol, 1,6 hexanediol, pentaerythritol,
Sorbitol, glycerin, neopentyl glycol,
Examples thereof include a saturated polyester resin obtained by an ester bond with a polyhydric alcohol such as 1,4 cyclohexanedimethanol, 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 Copolymer Elastomer Acrylonitrile butadiene copolymer prepolymer having a terminal hydroxyl group, which is commercially available as poly BD retied resin manufactured by Sinclair Petrochemical, 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 poly BD retied resin R-15 manufactured by Sinclair Petrochemical Co. 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 prepolymers thereof include styrene-butadiene rubber, chlorinated rubber, acrylic rubber, isoprene rubber and cyclized products thereof (CIR701 manufactured by Japan Synthetic Rubber), 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 has the magnetic characteristics as described above, and thus exhibits a high magnetic shield effect even with a thickness of 5 μm, and 200 μm is required for shielding a magnetic field having a strength such that the shield material is not magnetically saturated. This is because the magnetic shield effect is not significantly improved even if the thickness is increased, and it is also advantageous in terms of cost if the thickness is 200 μm or less.

When the magnetic shield material of the present invention is molded or applied in a desired shape, a magnetic field having a high directionality can be obtained by applying an orientation magnetic field or mechanically orienting the magnetic shield material. When the shield material is plate-shaped or film-shaped, 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-mentioned thickness range.

V. Specific Effect of the Invention The magnetic shield material of the present invention contains a soft magnetic powder composed of amorphous alloy soft magnetic particles having a predetermined average thickness and aspect ratio, and has a predetermined maximum magnetic permeability and coercive force.

Therefore, the magnetic shield material of the present invention has a high magnetic shield effect, and when the magnetic shield material is formed into a plate shape or a film shape, it is 5 to 200 especially for a magnetic field in a direction parallel to the film surface.
The desired effect can be obtained with a thickness of about μm, and in addition to magnetic shields for speakers, CRTs, etc., it has a very wide range of application and can be manufactured at low cost.

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 by a vibrating ball mill to obtain coarse powder having an average particle size of 32 µm, which was crushed by a pin-type mill and further heat-treated to obtain a magnetic shield. A soft magnetic powder sample was prepared.

However, the pulverization conditions and heat treatment conditions in the pin type mill are as shown in Table 1.

The temperature and time of the heat treatment conditions shown by A, B and C in Table 1 are as follows.

A: 450 ° C., 1 hour B: 400 ° C., 1 hour C: 350 ° C., 1 hour Further, the heat treatment was performed in a N ₂ atmosphere.

 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.

As the magnetic characteristics of the soft magnetic powder sample, the maximum magnetic permeability (μm) and the coercive force (Hc) in a DC magnetic field are shown in Table 1.
Also described in.

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 (manufactured by Sekisui Chemical Co., Ltd.)] 100 parts by weight Polyurethane [Nipporan 2304 (manufactured by Nippon Polyurethane Co.)] 100 parts by weight (solid component conversion) (curing material) Polyisocyanate [Coronate HL (manufactured by Nippon Polyurethane Co.)] 10 parts by weight (solvent) MEK 850 parts by weight Table 1 also shows the filling ratio 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 of each of these shield plate samples was measured, and sample No. 5 was designated as 1 and expressed as a relative value.

 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 .

Further, as the magnetic properties of the shield plate samples, the maximum permeability at DC magnetic field (mu _m) and coercive force (Hc), Table 1
Also described in.

In addition, in Sample No. 6, there was a variation in the shield ratio.

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

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.

Front page continuation (72) Inventor Hirosumi Shimizu 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDC Inc. (72) Inventor Ichiho Hirai 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDC Corporation (72) Inventor Ryohei Mimura 1-5-1 Taito, Taito-ku, Tokyo Tokyo Magnetic Printing Co., Ltd. (72) Inventor Atsushi Makimura 1-5-1 Taito, Taito-ku, Tokyo Tokyo Magnetic Printing Co., Ltd. (72) Inventor Hiroshi Hosaka 1-5-1 Taito, Taito-ku, Tokyo Within Tokyo Magnetic Printing Co., Ltd.

Claims (3)

[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 to 1 μm.
m, an average outer diameter / average thickness ratio of 10 to 10000 of amorphous alloy soft magnetic particles, and the composition of the amorphous alloy soft magnetic particles is represented by the formula Fe _u M _x (Si, B) _w (where M is Cr, Cr, 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). ), The maximum permeability in a DC magnetic field is 15 to 70, and the coercive force is 5 to 20 (O
e) A magnetic shield material characterized in that 2. The magnetic shield material according to claim 1, wherein the filling rate of the amorphous alloy soft magnetic particles in the magnetic shield material is 60 to 95 wt% or more, and the binder contains polyurethane. . 3. 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 or 2, wherein the amount of the amorphous alloy soft magnetic particles having a size less than m is 10 wt% or less.