JPH07183110A - Electromagnetic wave shielding powder piece - Google Patents
Electromagnetic wave shielding powder pieceInfo
- Publication number
- JPH07183110A JPH07183110A JP5345685A JP34568593A JPH07183110A JP H07183110 A JPH07183110 A JP H07183110A JP 5345685 A JP5345685 A JP 5345685A JP 34568593 A JP34568593 A JP 34568593A JP H07183110 A JPH07183110 A JP H07183110A
- Authority
- JP
- Japan
- Prior art keywords
- powder piece
- powder
- electromagnetic wave
- alloy
- wave shielding
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、静磁場および低周波域
から高周波域までの広い周波数帯域の電磁波に対して優
れたシールド効果を有する電磁波シールド粉片に関す
る。なお、本発明においては、１０ MHz未満の低周波領
域と１０ MHz以上の高周波領域のものを含めて電磁波と
云い、便宜上、この電磁波の他に静磁場のシールドを含
めて電磁波シールドと云う。また球状、塊状、針状など
の粉末および鱗片状、フレーク状あるいは短冊状の細長
い薄片を含めて粉片と云う。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave shielding powder piece having an excellent shielding effect against static magnetic fields and electromagnetic waves in a wide frequency band from a low frequency region to a high frequency region. In the present invention, a low frequency region of less than 10 MHz and a high frequency region of 10 MHz or more are referred to as electromagnetic waves, and for convenience, in addition to this electromagnetic wave, a static magnetic field shield is also referred to as an electromagnetic wave shield. In addition, powders such as spherical, lump, and needle-shaped powders and scale-shaped, flake-shaped, or strip-shaped elongated flakes are referred to as powder flakes.
【０００２】[0002]
【従来技術とその問題点】近年、電子機器が広範に使用
されるようになり、外部の電磁波がこれらの機器に及ぼ
す影響や、電子機器から漏洩した電磁波の影響が問題に
なっており、この問題に対処するため、従来、各種の電
磁波シールド材が提案されているが、従来の磁気シール
ド材は主に静磁場や低周波域の電磁波を対象とした遮蔽
材であり、高周波域の電磁波に対しては遮蔽効果がな
い。また、このような磁気シールド材の他に銅箔などの
導電性材料を用いることも知られているが、これは高周
波域での電磁波遮蔽効果を有するものの、静磁場や低周
波域では遮蔽効果がない。このように、現在、低周波域
から高周波域に至る広い周波数領域において優れた電磁
波シールド効果を有するシールド材は得られていない。2. Description of the Related Art In recent years, electronic devices have come into widespread use, and the influence of external electromagnetic waves on these devices and the influence of electromagnetic waves leaked from electronic devices have become a problem. In order to deal with the problem, various kinds of electromagnetic wave shield materials have been proposed so far, but the conventional magnetic shield material is a shield material mainly for static magnetic fields and electromagnetic waves in the low frequency range, On the other hand, there is no shielding effect. It is also known to use a conductive material such as copper foil in addition to such a magnetic shield material, which has an electromagnetic wave shielding effect in a high frequency range, but has a shielding effect in a static magnetic field or a low frequency range. There is no. Thus, at present, a shield material having an excellent electromagnetic wave shielding effect in a wide frequency range from a low frequency range to a high frequency range has not been obtained.
【０００３】電界と磁界は互いに直交して一定の周波数
で振動しながら進行するが、電磁波の伝播においては、
一般に、周波数の低い領域（１０ MHz未満）では磁界成
分の影響が大きいので、透磁率が高く保磁力の低い軟磁
性材料がその周波数領域のシールド材として適してお
り、また周波数の高い領域（１０MHz 以上）では電界成
分の影響が大きく、従って導電率の高い材料が高周波数
領域のシールド材として適している。即ちシールド材と
しては、静磁場および低周波数領域の電磁波に対しては
高透磁率であり低保磁力の軟磁性材料が適し、高周波数
領域の電磁波に対しては高導電率を有する材料が適す
る。従って、静磁場を含む低周波数域から高周波数域に
至る広い周波数領域の電磁波を遮断するには、高導電率
特性を有し、しかも透磁率が高く低保磁力である軟磁性
材料が求められるが、同一成分組成でこのような特性を
有する材料を得ることが難しく、このため高導電性材料
と軟磁性材料とを複合したシールド材が必要とされる。An electric field and a magnetic field are orthogonal to each other and travel while oscillating at a constant frequency. In the propagation of electromagnetic waves,
Generally, in the low frequency region (less than 10 MHz), the influence of the magnetic field component is large, so a soft magnetic material having a high magnetic permeability and a low coercive force is suitable as a shield material in that frequency region, and a high frequency region (10 MHz). In the above), the effect of the electric field component is large, and therefore, a material having high conductivity is suitable as a shield material in the high frequency region. That is, as the shield material, a soft magnetic material having a high magnetic permeability and a low coercive force is suitable for an electromagnetic field in a static magnetic field and a low frequency region, and a material having a high conductivity is suitable for an electromagnetic wave in a high frequency region. . Therefore, in order to block electromagnetic waves in a wide frequency range from a low frequency range including a static magnetic field to a high frequency range, a soft magnetic material having a high conductivity characteristic and a high magnetic permeability and a low coercive force is required. However, it is difficult to obtain a material having such characteristics with the same component composition, and thus a shield material composed of a highly conductive material and a soft magnetic material is required.
【０００４】このような複合シールド材の一例として、
特開平2-84540 号には、炭素繊維の表面に鉄、コバルト
系非晶質合金を被覆したシールド材、および炭素繊維表
面に導電性金属を被覆した後に鉄、コバルト系非晶質合
金を被覆したシールド材が開示されている。ところが上
記シールド材は炭素繊維ないし導電性金属部分の導電材
料が磁性材料によって覆われているので、導電材どうし
が直接には接触しないためにシールド材全体の導電性が
不十分である。また特開昭61-253136 号には、鉄、コバ
ルト系合金線材の表面に導電性金属を被覆した繊維を用
いて織布を形成し、これを樹脂でシート状に成形したシ
ールド材が開示されているが、これは、金属被覆合金線
材の加工に手間がかかり、しかも織布の製造とその成形
工程も繁雑である。一方、特開昭58-101499 号には、導
電性粉末と磁性粉末を配合した樹脂成形品の表面に導電
材ないし磁性材を積層した複合シールド材が記載されて
いるが、この複合シールド材は加工性に優れるものの、
樹脂中で導電性粉末と磁性粉末が混在するために導電性
粉末の間に磁性粉末が介在し、導電性粉末相互の接触が
充分ではないために高周波域の電磁波を十分にシールド
できない問題がある。As an example of such a composite shield material,
Japanese Unexamined Patent Publication No. 2-84540 discloses a shield material in which the surface of carbon fiber is coated with iron and a cobalt-based amorphous alloy, and a carbon fiber surface is coated with a conductive metal and then coated with an iron-cobalt-based amorphous alloy. The disclosed shield material is disclosed. However, since the conductive material of the carbon fiber or the conductive metal portion of the shield material is covered with the magnetic material, the conductive materials do not come into direct contact with each other, so that the overall conductivity of the shield material is insufficient. Further, Japanese Patent Application Laid-Open No. 61-253136 discloses a shield material in which a woven cloth is formed by using a fiber in which a conductive metal is coated on the surface of an iron-cobalt-based alloy wire, and the woven cloth is molded into a sheet with a resin. However, this requires time and labor for processing the metal-coated alloy wire, and the manufacturing process of the woven fabric and its forming process are complicated. On the other hand, Japanese Patent Laid-Open No. 58-101499 describes a composite shield material in which a conductive material or a magnetic material is laminated on the surface of a resin molded product in which conductive powder and magnetic powder are mixed. Although excellent in workability,
Since the conductive powder and the magnetic powder are mixed in the resin, the magnetic powder is present between the conductive powders, and the mutual contact between the conductive powders is not sufficient, so there is a problem that electromagnetic waves in the high frequency range cannot be sufficiently shielded. .
【０００５】[0005]
【発明の解決課題】本発明は従来のシールド材における
上記問題点を解決した電磁波シールド材を提供するもの
であって、静磁場を含む低周波域から高周波域に至る広
い周波数帯域の電磁波に対して優れた遮蔽効果を有する
シールド材を提供することを目的とする。本発明におい
て、その好適な態様として、一定のアスペクト比を有す
る高透磁率の鱗片状粉片表面を導電性の高い金属で被覆
した粉片は、静磁場および低周波域から高周波域に至る
広い周波数領域の電磁波に対して優れた遮蔽効果を発揮
し、しかもこの粉片を樹脂に配合してなるシールド材は
加工性に優れることが見出された。本発明は係る知見に
基づき従来の上記課題を解決したものである。DISCLOSURE OF THE INVENTION The present invention provides an electromagnetic wave shield material that solves the above-mentioned problems in conventional shield materials, and is suitable for electromagnetic waves in a wide frequency band including a static magnetic field from a low frequency range to a high frequency range. And a shielding material having an excellent shielding effect. In the present invention, as a preferred embodiment thereof, a powder piece obtained by coating the surface of a highly magnetic scaly powder piece having a constant aspect ratio with a highly conductive metal is wide from a static magnetic field and a low frequency range to a high frequency range. It has been found that a shielding material that exhibits an excellent shielding effect against electromagnetic waves in the frequency region and that this powder piece is mixed with resin has excellent processability. The present invention has solved the above-mentioned conventional problems based on such findings.
【０００６】[0006]
【発明の構成】本発明は以下の構成を有する電磁波シー
ルド粉片を提供する。 （１）高透磁率および低保磁力の軟磁性粉片に導電性金
属が被覆されていることを特徴とする電磁波シールド粉
片。 （２）上記軟磁性粉片が、硅素鋼、センダスト合金、パ
ーマロイ合金、Ｃｏ系ないしＦｅ系非晶質合金粉片ある
いはフェライト系酸化物粉片である上記(1) の電磁波シ
ールド粉片。 （３）上記導電性金属が、銅、銀、ニッケル、金、パラ
ジウムまたはこれらの合金である上記(1) または(2) の
電磁波シールド粉片。 （４）平均粒径が１μm 〜５cmでアスペクト比が５〜１
０5 である上記(1) 〜(3) のいずれかの電磁波シールド
粉片。 （５）平均粒径５〜２００μm 、アスペクト比１０〜５
０のＦｅ系非晶質合金粉片に、銅、銀またはニッケルが
被覆粉片の５〜７５重量％被覆されている上記(1) の電
磁波シールド粉片。The present invention provides an electromagnetic wave shielding powder piece having the following configuration. (1) An electromagnetic wave shielding powder piece characterized in that a soft magnetic powder piece having a high magnetic permeability and a low coercive force is coated with a conductive metal. (2) The electromagnetic shielding powder piece according to (1) above, wherein the soft magnetic powder piece is silicon steel, Sendust alloy, permalloy alloy, Co-based or Fe-based amorphous alloy powder piece or ferrite-based oxide powder piece. (3) The electromagnetic shielding powder piece according to (1) or (2) above, wherein the conductive metal is copper, silver, nickel, gold, palladium or an alloy thereof. (4) Average particle size is 1 μm to 5 cm and aspect ratio is 5 to 1
0 5 a is above (1) to any one of the electromagnetic wave shielding powder pieces (3). (5) Average particle size 5 to 200 μm, aspect ratio 10 to 5
The Fe-based amorphous alloy powder piece of No. 0 is coated with copper, silver or nickel in an amount of 5 to 75% by weight of the coated powder piece.
【０００７】[0007]
【具体的な説明】以下、本発明を実施例と共に詳細に説
明する。本発明の電磁波シールド粉片は高透磁率および
低保磁力を有する軟磁性粉片に導電性金属を被覆したこ
とを特徴とするものである。ここで高透磁率および低保
磁力を有するとは、従来、磁気シールド粉片として用い
られているものと同等かそれを上回る透磁率を有し、同
等かそれ以下の保磁力を有することを言う。該軟磁性粉
片としては、例えば、硅素鋼、センダスト合金、パーマ
ロイ合金またはＣｏ系ないしＦｅ系非晶質合金の粉片お
よび絶縁性のフェライト系酸化物粉片が好ましい。代表
的なこれらの軟磁性材の保磁力は１．０Oe以下であり、
磁気シールド粉片として用いるには保磁力は少なくとも
１０Oe以下が好ましい。[Detailed Description] Hereinafter, the present invention will be described in detail with reference to Examples. The electromagnetic wave shielding powder piece of the present invention is characterized in that a soft magnetic powder piece having a high magnetic permeability and a low coercive force is coated with a conductive metal. Here, having a high magnetic permeability and a low coercive force means having a magnetic permeability equal to or higher than that conventionally used as a magnetic shield powder piece, and having a coercive force equal to or lower than that. . As the soft magnetic powder particles, for example, powder particles of silicon steel, Sendust alloy, permalloy alloy or Co-based or Fe-based amorphous alloy and insulating ferrite-based oxide powder particles are preferable. The coercive force of these typical soft magnetic materials is 1.0 Oe or less,
For use as a magnetic shield powder piece, the coercive force is preferably at least 10 Oe or less.
【０００８】上記軟磁性粉片の平均粒径は１μm 〜５cm
の範囲が好ましい。平均粒径が１μm 未満であると、粉
片が凝集し易くなるので粉片表面に導電性金属を均一に
被覆するのが困難になる。平均粒径が５cmを超えると樹
脂中で均一に分散し難い。樹脂に混合する場合は１mm以
下が好ましい。The average particle size of the soft magnetic powder pieces is 1 μm to 5 cm.
Is preferred. If the average particle size is less than 1 μm, the powder pieces tend to aggregate, and it becomes difficult to uniformly coat the surface of the powder pieces with the conductive metal. If the average particle size exceeds 5 cm, it is difficult to uniformly disperse in the resin. When mixed with a resin, it is preferably 1 mm or less.
【０００９】上記軟磁性粉片は、球状、塊状、針状、鱗
片状、フレーク状あるいは短冊状など細長い形状のもの
を用いることができる。なお、電磁波シールド効果を高
めるには、電磁波シールド粉片によって平面を出来るだ
け隙間無く覆うことが必要であり、このためにはフレー
ク状、鱗片状、短冊状の粉片が好ましく、特にアスペク
ト比が５以上の粉片が好ましい。アスペクト比とは粉片
の平均厚さに対する平均直径の比（平均直径／平均厚
さ）を云う。粉片の偏平面の平均直径は顕微鏡下の観察
により測定でき、また平均厚さは平面に配向した粉片の
断面を顕微鏡下で観察して測定できる。偏平な粉片の３
次元観察において、最も小さい長さが偏平面の厚さであ
る。なお、粉片の平均粒径はレーザを用いた粒度分布計
などによって重量基準累積50％を測定することによって
求めることができる。偏平粉片の平均粒径は、偏平面の
長径、短径および厚さを含めた平均値である。The soft magnetic powder pieces may be elongated in shape such as spherical shape, lump shape, needle shape, scale shape, flake shape or strip shape. In order to enhance the electromagnetic wave shielding effect, it is necessary to cover the flat surface with the electromagnetic wave shielding powder pieces as closely as possible. For this purpose, flaky, scale-like, and strip-like powder pieces are preferable, and the aspect ratio is particularly preferable. A powder piece of 5 or more is preferable. The aspect ratio means the ratio of the average diameter to the average thickness of the powder pieces (average diameter / average thickness). The average diameter of the flat surface of the powder piece can be measured by observation under a microscope, and the average thickness can be measured by observing the cross section of the powder piece oriented in a plane under the microscope. 3 of flat powder pieces
In dimensional observation, the smallest length is the thickness of the plane. The average particle size of the powder pieces can be obtained by measuring the weight-based cumulative 50% with a particle size distribution meter using a laser. The average particle diameter of the flat powder pieces is an average value including the major axis, minor axis and thickness of the flat surface.
【００１０】前述したように、静磁場および低周波域か
ら高周波域に至る広い周波数域の電磁波に対して高い電
磁波シールド効果を達成するためには、上記電磁波シー
ルド粉片ができるだけ隙間なく平面を覆って分散されて
いることが好ましい。上記アスペクト比の粉片は、平面
に均一に分散し、少ない配合量で広い面積を覆うことが
できるので有利である。アスペクト比が５未満である
と、配合量の割りには電磁波シールド効果が低くなるの
で好ましくない。アスペクト比が１０5 を上回ると、平
均厚さが0.5 μm のとき、平均直径が５cmより大きくな
るので樹脂中で均一に分散させるのが困難になる。な
お、一般に用いられる偏平粉片の平均粒径は１μm 〜５
cm程度であり、概ねアスペクト比は５〜１０4 程度であ
る。As described above, in order to achieve a high electromagnetic wave shielding effect against a static magnetic field and electromagnetic waves in a wide frequency range from a low frequency range to a high frequency range, the electromagnetic wave shielding powder pieces cover the flat surface as closely as possible. Are preferably dispersed. The powder particles having the above-mentioned aspect ratio are advantageous because they can be uniformly dispersed on a flat surface and can cover a large area with a small blending amount. If the aspect ratio is less than 5, the electromagnetic wave shielding effect becomes low relative to the blending amount, which is not preferable. When the aspect ratio exceeds 10 5 , the average diameter becomes larger than 5 cm when the average thickness is 0.5 μm, which makes it difficult to uniformly disperse the resin in the resin. The average particle size of the commonly used flat powder pieces is 1 μm to 5 μm.
It is about cm, and the aspect ratio is about 5 to 10 4 .
【００１１】上記アスペクト比の粉片は、水アトマイズ
法などによって得られるほぼ球形の粒子を、例えば、ボ
ールミル等の機械的手段によって鱗片状に加工するか、
あるいは、溶融金属を鱗片状に固化して製造することが
できる。工程の簡素化、粉片表面の平滑性という点で
は、後者の方法が好ましいが、後者の方法では、比較的
小粒径の粉片を得ることが難しいため、用途により、い
ずれか適する方法を選択するのがよい。またアスペクト
比は製造条件を適宜変更することにより制御することが
できる。フェライト系の鱗片状軟磁性粉は、例えば酸化
マンガン、酸化亜鉛と酸化第二鉄を混合し焼成して得た
粒子を、ボールミル等の機械的手段によって鱗片状に加
工して得られる。The powder particles having the above aspect ratio are obtained by processing substantially spherical particles obtained by a water atomizing method or the like into scales by a mechanical means such as a ball mill, or
Alternatively, it can be produced by solidifying molten metal into a scale. The latter method is preferable in terms of the simplification of the process and the smoothness of the surface of the powder pieces, but it is difficult to obtain the powder pieces having a relatively small particle size by the latter method. Good to choose. The aspect ratio can be controlled by appropriately changing the manufacturing conditions. The ferritic scale-like soft magnetic powder is obtained by processing particles obtained by mixing and firing manganese oxide, zinc oxide and ferric oxide into a scale-like shape by a mechanical means such as a ball mill.
【００１２】以上のように本発明の粉片は上記軟磁性粉
片の表面に導電性が被覆されたものである。該粉片の表
面に適度な量の導電性金属被覆を有するものは、後述す
る実施例に示すように、導電性金属被覆を有するにも拘
らず、静磁場や低周波域において、このような金属被覆
を有しない軟磁性粉片と同等の電磁波シールド効果を発
揮し、他方、高周波域においては、導電性金属被覆が電
磁波シールド効果を発揮する。従って、静磁場を含む低
周波数域から高周波数域に至る広い周波数域の電磁波に
対して優れた遮蔽効果を得ることができる。このような
電磁波シールド効果は、後述する比較例に示すように、
軟磁性粉片と導電性粉片とを単純に混合しも得ることが
できない。As described above, the powder piece of the present invention is obtained by coating the surface of the soft magnetic powder piece with conductivity. Those having an appropriate amount of conductive metal coating on the surface of the powder piece have such a tendency in a static magnetic field or a low frequency range as described in Examples to be described later that they have a conductive metal coating. An electromagnetic wave shielding effect equivalent to that of a soft magnetic powder piece having no metal coating is exhibited, while a conductive metal coating exhibits an electromagnetic wave shielding effect in a high frequency range. Therefore, it is possible to obtain an excellent shielding effect against electromagnetic waves in a wide frequency range including a low frequency range including a static magnetic field and a high frequency range. Such an electromagnetic wave shielding effect, as shown in a comparative example described later,
Even if the soft magnetic powder pieces and the conductive powder pieces are simply mixed, they cannot be obtained.
【００１３】軟磁性粉片表面に被覆される導電性金属
は、高い導電性を有するものであれば良く、例えば、
銅、銀、ニッケル、金、パラジウム、またはこれらの合
金などが用いられる。コスト、安定性、導電性を考慮す
ると、銀または銅が好ましい。導電性金属の被覆方法と
しては、既知の方法を使用することができるが、無電解
めっき法が特に好ましい。この方法によれば、粉片表面
に一定量の均一な被覆を得ることができる。無電解めっ
きは、常法に従って行えばよく、例えば、軟磁性粉片を
洗浄して表面を活性化し、錯化剤と還元剤を含む水溶液
中に添加し、これに導電性金属の塩を滴下して行なう。
錯化剤としては、例えば、アンモニア水、エチレンジア
ミン四酢酸、ニトリロ三酢酸、トリエチレンテトラミン
六酢酸等の塩類が挙げられ、還元剤としては、ホルマリ
ン、ヒドラジン及びその誘導体、酒石酸、ブドウ糖等を
用いることができる。これらは、使用する導電性金属に
応じて適宜選択すればよい。導電性金属の塩には、例え
ば、硝酸塩、硫酸塩等を用いることができる。The conductive metal coated on the surface of the soft magnetic powder piece may be any one having a high conductivity, for example,
Copper, silver, nickel, gold, palladium, or alloys thereof are used. Silver or copper is preferable in consideration of cost, stability, and conductivity. As a method for coating the conductive metal, a known method can be used, but an electroless plating method is particularly preferable. According to this method, a certain amount of uniform coating can be obtained on the surface of the powder pieces. The electroless plating may be performed according to a conventional method. For example, the soft magnetic powder pieces are washed to activate the surface, added to an aqueous solution containing a complexing agent and a reducing agent, and a salt of a conductive metal is added dropwise. Then do it.
Examples of complexing agents include salts of ammonia water, ethylenediaminetetraacetic acid, nitrilotriacetic acid, triethylenetetraminehexaacetic acid, etc., and reducing agents such as formalin, hydrazine and its derivatives, tartaric acid, and glucose are used. You can These may be appropriately selected according to the conductive metal used. As the salt of the conductive metal, for example, nitrate, sulfate or the like can be used.
【００１４】導電性金属の好ましい被覆量は、軟磁性粉
片の種類、粉片の大きさ、形状および導電性金属の種類
などによって異なり、例えば、フェライト系酸化物は合
金系粉片よりも比重が軽いので、ほぼ同じ厚さの被覆を
有する同形の粉片でも、フェライト系粉片を用いた場合
には合金系粉片を用いた場合よりも被覆粉片での金属重
量比（％）が高くなる。一例として後述の実施例に示す
ように、平均粒径５〜２００μm 、アスペクト比１０〜
５０の鉄系軟磁性合金粉片を用い、銀、銅、ニッケルを
被覆したとき、この被覆量は被覆粉片の単位重量あたり
約５〜７５重量％が適当であり、１０〜５０重量％が好
ましく、さらに１０〜２０重量％がより好ましい。被覆
量が５重量％より少ないと導電性が低くなる。一方、被
覆量が７５重量％を上回ると被覆された粉片全体の飽和
磁化が小さくなると共に粉片が相互に接触しても間に介
在する金属被覆が厚いので粉片全体の磁気抵抗が大きく
なり、シールド材の透磁率が下がるので電磁波シールド
効果が十分に現われない。被覆量は、例えば無電解めっ
き法の場合には、めっき液に投入する軟磁性粉片の添加
量あるいはめっき液中の金属濃度などを調整して制御す
ることができる。The preferable amount of the conductive metal coated varies depending on the type of the soft magnetic powder piece, the size and shape of the powder piece, the type of the conductive metal, and the like. For example, a ferrite-based oxide has a specific gravity higher than that of an alloy-based powder piece. Since the powder is light, even if the powder particles of the same shape having a coating of almost the same thickness, the metal weight ratio (%) in the coated powder piece is higher when the ferrite powder piece is used than when the alloy powder piece is used. Get higher As an example, as shown in the examples below, the average particle size is 5 to 200 μm, and the aspect ratio is 10 to 10.
When 50 pieces of iron-based soft magnetic alloy powder pieces are used and coated with silver, copper, and nickel, the coating amount is appropriately about 5 to 75% by weight, and 10 to 50% by weight per unit weight of the coated powder pieces. More preferably, it is more preferably 10 to 20% by weight. When the coating amount is less than 5% by weight, the conductivity becomes low. On the other hand, if the coating amount exceeds 75% by weight, the saturation magnetization of the coated powder pieces as a whole becomes small, and even if the powder pieces contact each other, the intervening metal coating is thick, so the magnetic resistance of the whole powder pieces is large. As a result, the magnetic permeability of the shield material is lowered, so that the electromagnetic wave shielding effect is not sufficiently exhibited. In the case of the electroless plating method, for example, the coating amount can be controlled by adjusting the addition amount of the soft magnetic powder pieces added to the plating solution or the metal concentration in the plating solution.
【００１５】上記電磁波シールド粉片の使用例として
は、樹脂に混練され樹脂成形体中に含有されたフィラー
材、成形品に充填される充填材、シート状部材の表面に
均一に分散して付着された被覆材、あるいは塗料中に混
合され塗膜中に含有されたフィラー材などとして用いる
ことができる。上記電磁波シールド粉片を樹脂中に均一
に混練分散させて成型品を形成する場合、樹脂として
は、導電性の樹脂成形品を製造する際に使用される一般
的な樹脂のいずれも使用することができる。これらの樹
脂としては、例えば、ポリ塩化ビニル樹脂、ポリエチレ
ン樹脂、ＡＢＳ樹脂、エポキシ樹脂、アクリル樹脂、シ
リコン樹脂などが挙げられる。Examples of the use of the above-mentioned electromagnetic wave shielding powder pieces include a filler material kneaded with a resin and contained in a resin molded body, a filler to be filled in a molded product, and evenly dispersed and adhered to the surface of a sheet-shaped member. It can be used as a coating material or a filler material mixed in a paint and contained in a coating film. When forming the molded product by uniformly kneading and dispersing the electromagnetic wave shielding powder pieces in the resin, as the resin, use any of the common resins used in the production of conductive resin molded products You can Examples of these resins include polyvinyl chloride resin, polyethylene resin, ABS resin, epoxy resin, acrylic resin, and silicone resin.
【００１６】また、上記電磁波シールド粉片を塗料中に
混合し、均一に分散させることにより静磁場を含む低周
波域から高周波域の広い周波数領域の電磁波に対して優
れた電磁波シールド効果を有する塗料が得られる。塗料
としては、一般に使用される塗料のいずれも使用可能で
ある。これらの塗料としては例えば、アクリル樹脂系塗
料、エポキシ樹脂系塗料、ウレタン樹脂系塗料が挙げら
れる。また本発明の電磁波シールド粉片をインクに配合
して用いることができる。インクの種類は限定されな
い。また配合量はインクの種類等によって適宜定められ
る。Further, by mixing the above-mentioned electromagnetic wave shielding powder pieces in a coating material and uniformly dispersing it, a coating material having an excellent electromagnetic wave shielding effect against electromagnetic waves in a wide frequency range from a low frequency range including a static magnetic field to a high frequency range. Is obtained. As the paint, any of the commonly used paints can be used. Examples of these paints include acrylic resin-based paints, epoxy resin-based paints, and urethane resin-based paints. Further, the electromagnetic wave shielding powder pieces of the present invention can be used by being mixed with ink. The type of ink is not limited. The blending amount is appropriately determined depending on the type of ink and the like.
【００１７】本発明の電磁波シールド粉片はシールド材
中で平面状に配向され、かつ層状に積層されていること
が好ましい。層状に配向させることにより、粉片相互の
接触密度が向上し、隙間なく平面を覆うことができるの
で高いシールド効果を発揮できる。粉片を配向させるに
は、粉片を樹脂中に混練分散させる際に、混練物に所定
の圧力を加えればよく、または磁場を与えて配向させて
もよい。また接着剤を塗布した樹脂シートの表面に上記
粉片を均一に分散させ、この分散を繰返して上記粉片を
層状に積層させることができる。あるいは樹脂シートの
表面に上記粉片を含有した塗料を薄く塗布し、この塗布
を繰返して上記粉片を層状に積層させることができる。
なお上記電磁波シールド粉片を積層した状態にする場合
には、個々の粉片が厚すぎるとシート材の可撓性を損な
う虞があるので、平均厚さ５μ未満の粉片が好ましい。The electromagnetic wave shielding powder pieces of the present invention are preferably oriented in a plane in the shield material and are laminated in layers. By orienting in a layered form, the contact density between the powder particles is improved, and the flat surface can be covered without a gap, so that a high shielding effect can be exhibited. In order to orient the powder pieces, a predetermined pressure may be applied to the kneaded product when the powder pieces are kneaded and dispersed in the resin, or a magnetic field may be applied for orientation. In addition, the powder particles can be uniformly dispersed on the surface of the resin sheet coated with the adhesive, and the dispersion can be repeated to stack the powder particles in a layer. Alternatively, it is possible to apply a thin coating of the coating material containing the powder particles on the surface of the resin sheet, and repeat this application to stack the powder particles in layers.
In the case where the electromagnetic wave shielding powder pieces are laminated, if the individual powder pieces are too thick, the flexibility of the sheet material may be impaired. Therefore, the powder pieces having an average thickness of less than 5 μm are preferable.
【００１８】[0018]
【実施例および比較例】以下、本発明の実施例を比較例
と共に示す。なお以下の実施例は例示であり、本発明は
これに限定されない。EXAMPLES AND COMPARATIVE EXAMPLES Examples of the present invention are shown below together with comparative examples. The following examples are mere examples, and the present invention is not limited thereto.
【００１９】実施例１ Ｆｅ：74.3wt％，Ｓｉ：8.2wt ％，Ｂ：9.8wt ％，Ｃ
ｒ：5.6wt ％，Ｎｂ：2.1wt ％の組成を有する軟磁性合
金を水アトマイズ法で平均粒径２０μm のほぼ球形の非
晶質粒子に製造し、これをボールミルで粉砕し、平均粒
径１５μm 、アスペクト比３０の軟磁性合金鱗片を得
た。上記鱗片８０ｇをメタノールにて洗浄した後、１０
％塩酸に浸漬、撹拌して表面を活性化させた。別にエチ
レンジアミン四酢酸二ナトリウム１００ｇ、２５％アン
モニア水５０ml、３７％ホルマリン溶液５０mlの水溶液
１リットルを用意し、前記活性化した鱗片を入れ撹拌し、そ
の中に硝酸銀３２ｇ、２５％アンモニア水８０mlを含ん
だ水溶液５００mlを１時間かけて滴下した。この操作に
より銀２０ｇが還元され、銀被覆量２０重量％の軟磁性
合金鱗片（試料A1）を得た。同様の方法により銀被覆量
を変えた軟磁性合金鱗片（試料A2,A3,A4,A5 ）を得た。
上記鱗片の飽和磁化と保磁力を振動試料型磁力計にて測
定し、また電気抵抗値（圧粉抵抗値）を測定した。この
結果を表１に示す。また比較例として銀を被覆しない上
記鱗片（試料A6）について同様に飽和磁化と保磁力を測
定した。この結果を併せて表１に示した。表１に示され
るように、本発明の軟磁性合金鱗片（試料A1〜A5）は導
電性金属被覆を有しない従来の磁気シールド材（試料A
6）と比較すると、飽和磁化は僅かに低いが保磁力は同
等であり、一方、電気抵抗値は大幅に低く約1/10〜1/10
00である。Example 1 Fe: 74.3 wt%, Si: 8.2 wt%, B: 9.8 wt%, C
A soft magnetic alloy having a composition of r: 5.6 wt% and Nb: 2.1 wt% was produced by a water atomization method into substantially spherical amorphous particles having an average particle size of 20 μm, which were crushed by a ball mill to obtain an average particle size of 15 μm. A soft magnetic alloy scale having an aspect ratio of 30 was obtained. After washing 80 g of the scale with methanol, 10
% Hydrochloric acid was dipped and stirred to activate the surface. Separately, prepare 100 g of disodium ethylenediaminetetraacetate, 50 ml of 25% ammonia water, and 50 ml of 37% formalin solution, and add 1 L of the aqueous solution to the activated scale, and stir the mixture. 500 ml of a concentrated aqueous solution was added dropwise over 1 hour. By this operation, 20 g of silver was reduced to obtain a soft magnetic alloy scale (sample A1) having a silver coating amount of 20% by weight. Soft magnetic alloy flakes (Samples A2, A3, A4, A5) with different silver coating amounts were obtained by the same method.
The saturation magnetization and coercive force of the scales were measured with a vibrating sample magnetometer, and the electric resistance value (powder resistance value) was measured. The results are shown in Table 1. Further, as a comparative example, the saturation magnetization and the coercive force were similarly measured for the above scales (sample A6) not coated with silver. The results are also shown in Table 1. As shown in Table 1, the soft magnetic alloy flakes of the present invention (Samples A1 to A5) are conventional magnetic shield materials (Sample A) that do not have a conductive metal coating.
Compared with 6), the saturation magnetization is slightly lower, but the coercive force is the same, while the electrical resistance is significantly lower, about 1/10 to 1/10.
00.
【００２０】[0020]
【表１】 試料 飽和磁化 保磁力 電気抵抗値 銀被覆量 備考 (emu/g) (Oe) (Ω・□) (wt％) Ａ1 ８５ １０ 1.5 ×10-3 ２０ 実施例 Ａ2 ７５ １０ 1.0 ×10-3 ３０ 々 Ａ3 ５０ １０ 5.0 ×10-4 ５０ 々 Ａ4 ３０ １０ 4.0 ×10-4 ７５ 々 Ａ5 １００ １０ 8.6 ×10-2 ５ 々 Ａ6 １１０ １０ 5.3 ×10-1 ０ 比較例 [Table 1] Sample Saturation magnetization Coercive force Electric resistance Silver coverage Remark (emu / g) (Oe) (Ω ・ □) (wt%) A1 85 10 1.5 × 10 -3 20 Example A2 75 10 1.0 × 10 -3 30 s A3 50 10 5.0 × 10 -4 50 s A4 30 10 4.0 × 10 -4 75 people A5 100 10 8.6 × 10 -2 5 s A6 110 10 5.3 × 10 -1 0 Comparative example
【００２１】実施例２ 実施例１と同様にして、Ｆｅ：74.3wt％、Ｓｉ： 8.2wt
％、Ｂ： 9.8wt％、Ｃｒ： 5.6wt％、Ｎｂ： 2.1wt％の
組成を有する軟磁性合金を水アトマイズ法により平均粒
径２０μm のほぼ球状の非結晶粒子に製造し、これをボ
ールミルで粉砕して平均粒径５μm アスペクト比１０の
鱗片を得た。また、同一組成の平均粒径２００μm 、ア
スペクト比５０の鱗片を得た。これらの鱗片におのおの
実施例１で示した方法で銀を３０wt％（試料B1）、１０
wt％（試料B2）被覆した。一方、実施例１で用いた平均
粒径１５μm 、アスペクト比３０の軟磁性合金鱗片８０
ｇをメタノールにて洗浄した後、１０％塩酸に浸漬、撹
拌して表面を活性化させた。別にクエン酸ナトリウム２
００ｇおよび硫酸ヒドラジン１５０ｇをイオン交換水１
リットルに溶解させ、カセイソーダでｐＨ９に調整した。こ
のメッキ浴に活性化した前記鱗片を入れて撹拌し、７０
℃に保ち、その中に硫酸ニッケル９０ｇを溶解した水溶
液１００mlを１時間かけて滴下した。この操作によりニ
ッケル２０ｇが還元され、ニッケル被覆２０wt％の鱗片
（試料B3）を得た。この鱗片のニッケルの被覆厚は、約
０．２μm であった。また、実施例１で用いた平均粒径
１５μm 、アスペクト比３０の軟磁性合金鱗片８０ｇを
メタノールにて洗浄した後、１０％塩酸に浸漬、撹拌し
て表面を活性化させた。別にポリエチレングリコール２
ｇ、３７％ホルマリン８０ｇ、酒石酸カリウムナトリウ
ム１００ｇをイオン交換水１リットルに溶解させ、更にカセ
イソーダでｐＨ１１に調整した。このメッキ浴に活性化
した前記鱗片を入れ、その中に硫酸銅８０ｇを溶解した
水溶液１００mlを１時間かけて滴下した。この操作によ
り、銅２０ｇが還元され、銅被覆２０wt％の鱗片（試料
B4）を得た。該鱗片（試料B1〜B4）の飽和磁化、保磁
力、電気抵抗値（圧粉抵抗値）を表２に示す。Example 2 As in Example 1, Fe: 74.3 wt%, Si: 8.2 wt
%, B: 9.8 wt%, Cr: 5.6 wt%, Nb: 2.1 wt% soft magnetic alloy was produced by water atomization method into substantially spherical non-crystalline particles having an average particle size of 20 μm, and this was manufactured by a ball mill. It was crushed to obtain scales having an average particle size of 5 μm and an aspect ratio of 10. Further, scales having the same composition and an average particle diameter of 200 μm and an aspect ratio of 50 were obtained. Silver was added to each of these scales by the method shown in Example 1 at 30 wt% (Sample B1), 10
wt% (Sample B2) coated. On the other hand, the soft magnetic alloy flakes 80 having an average particle size of 15 μm and an aspect ratio of 30 used in Example 1 were used.
After washing g with methanol, it was immersed in 10% hydrochloric acid and stirred to activate the surface. Separately sodium citrate 2
00g and 150g of hydrazine sulfate are ion-exchanged water 1
It was dissolved in liter and adjusted to pH 9 with caustic soda. Add the activated scales to the plating bath and stir to 70
The temperature was maintained at 0 ° C., and 100 ml of an aqueous solution in which 90 g of nickel sulfate was dissolved was added dropwise over 1 hour. By this operation, 20 g of nickel was reduced, and a scale (sample B3) having a nickel coating content of 20 wt% was obtained. The nickel coating thickness of this scale was about 0.2 μm. Further, 80 g of the soft magnetic alloy flakes having an average particle diameter of 15 μm and an aspect ratio of 30 used in Example 1 were washed with methanol, immersed in 10% hydrochloric acid and stirred to activate the surface. Separately polyethylene glycol 2
g, 37% formalin 80 g, and potassium sodium tartrate 100 g were dissolved in 1 liter of ion-exchanged water, and the pH was adjusted to 11 with caustic soda. The activated scales were placed in this plating bath, and 100 ml of an aqueous solution in which 80 g of copper sulfate was dissolved was added dropwise thereto over 1 hour. By this operation, 20 g of copper is reduced, and a scale with a copper coating of 20 wt% (sample
B4) got. Table 2 shows the saturation magnetization, coercive force, and electric resistance value (powder resistance value) of the scales (Samples B1 to B4).
【００２２】[0022]
【表２】 試料 飽和磁化 保磁力 電気抵抗値 被覆量 平均粒径 (emu/g) (Oe) (Ω・□) (wt ％) （μｍ） Ｂ１ ７５ １０ 2.0×10-3 ３０(Ag) ５ Ｂ２ １００ １０ 1.5×10-3 １０(Ag) ２００ Ｂ３ ９０ １０ 4.0×10-3 ２０(Ni) １５ Ｂ４ ８５ １０ 1.5×10-3 ２０(Cu) １５ [Table 2] Sample Saturation magnetization Coercive force Electric resistance value Coverage Average particle size (emu / g) (Oe) (Ω ・ □) (wt%) (μm) B1 75 10 2.0 × 10 -3 30 (Ag) 5 B2 100 10 1.5 × 10 −3 10 (Ag) 200 B3 90 10 4.0 × 10 −3 20 (Ni) 15 B4 85 10 1.5 × 10 −3 20 (Cu) 15
【００２３】実施例３ 実施例１、２で得た電磁波シールド粉片（試料A1〜A5,
B1〜B4）７５重量％、ポリ塩化ビニル樹脂（三菱ビニル
社製）２５重量％及び可塑材（関東化学社製 DOP）５重
量％を常用の２本熱ロールを用いて混練し、配向させ、
放冷して厚さ２mmの板材に成形して本発明に係る電磁波
シールド樹脂成形品（試料C1〜C9）を得た。この成形品
（試料C1〜C9）について、図１に示す測定装置６０によ
り、その磁気シールド特性を測定した。該装置６０は載
置台６２を有し、該載置台６２の容器６３に強度既知の
磁石６４が装入されており、また磁気強度検出器７０の
検知端７１がスタンドのアーム６５に上下動自在に支持
されており、その先端が上記磁石６４に臨むように設置
されている。試料７２は容器６３に載せられ、試料７２
によって遮蔽された磁気強度を測定する。本実施例で
は、試料７２を設置しない状態で検知端７１が感知する
初期強度が各々100G, 50G,10G の磁石を用い、この位置
に検知端７１を設定し、各試料について上記磁石を入替
え、試料によって遮蔽された磁気強度を測定した。この
結果を表３に示した。Example 3 Electromagnetic wave shielding powder pieces obtained in Examples 1 and 2 (samples A1 to A5,
B1 to B4) 75% by weight, polyvinyl chloride resin (manufactured by Mitsubishi Vinyl Co., Ltd.) 25% by weight, and plasticizer (DOP manufactured by Kanto Kagaku Co., Ltd.) 5% by weight are kneaded and aligned by using a conventional two-roll roll,
It was allowed to cool and molded into a plate material having a thickness of 2 mm to obtain electromagnetic wave shielding resin molded products (Samples C1 to C9) according to the present invention. The magnetic shield characteristics of the molded products (Samples C1 to C9) were measured by the measuring device 60 shown in FIG. The apparatus 60 has a mounting table 62, a magnet 64 of known strength is loaded in a container 63 of the mounting table 62, and a detection end 71 of a magnetic strength detector 70 is vertically movable on an arm 65 of a stand. The magnet 64 is supported so that its tip faces the magnet 64. The sample 72 is placed on the container 63, and the sample 72
Measure the magnetic intensity shielded by. In the present embodiment, magnets having initial strengths of 100G, 50G, and 10G that are sensed by the detection end 71 without the sample 72 installed are used, and the detection end 71 is set at this position, and the magnets are replaced for each sample. The magnetic intensity shielded by the sample was measured. The results are shown in Table 3.
【００２４】一方、比較例として銀を被覆しない従来の
磁気シールド粉片（実施例１に使用した銀を被覆する前
の軟磁性合金粉片：試料A6）を塩化ビニル樹脂に７５重
量％配合し、同様な方法で板状に成形した樹脂成形品
（試料C11 ）を作成した。また従来の磁気シールド粉片
と銀粉片の混合粉片（軟磁性合金粉片：銀粉末＝４：１
重量比）を塩化ビニル樹脂に７５重量％配合し、同様な
方法で板状に成形した樹脂成形品（試料C12 ）を作成し
た。これらの試料について上記測定方法により、その遮
蔽された磁気強度を測定した。この結果を表３に示し
た。表３に示されるように、本発明の電磁波シールド粉
片は、静磁場において、導電性金属被覆を有するにも拘
らず従来の磁気シールド板に匹敵する磁気遮蔽効果を発
揮し、しかも後述する実施例４に示すように、高周波域
においては従来の磁気シールド材を用いたものよりも格
段に優れた電磁波遮蔽効果を発揮する。また本発明の電
磁波シールド粉片は従来の軟磁性粉片と銀粉末を混合し
たものよりも磁気遮蔽効果に優れる。On the other hand, as a comparative example, a conventional magnetic shield powder piece not coated with silver (soft magnetic alloy powder piece used in Example 1 before coating with silver: sample A6) was mixed with vinyl chloride resin in an amount of 75% by weight. A resin molded product (sample C11) molded in a plate shape was prepared by the same method. Also, a mixed powder piece of a conventional magnetic shield powder piece and a silver powder piece (soft magnetic alloy powder piece: silver powder = 4: 1)
(Weight ratio) was mixed with vinyl chloride resin in an amount of 75% by weight, and a resin molded product (sample C12) was formed into a plate shape by the same method. The shielded magnetic strength of these samples was measured by the above-mentioned measuring method. The results are shown in Table 3. As shown in Table 3, the electromagnetic wave shielding powder piece of the present invention exhibits a magnetic shielding effect comparable to that of the conventional magnetic shield plate in the static magnetic field, even though it has a conductive metal coating, and further described later. As shown in Example 4, in the high frequency range, the electromagnetic shielding effect is far superior to that using the conventional magnetic shield material. Further, the electromagnetic wave shielding powder piece of the present invention is superior to the conventional soft magnetic powder piece and silver powder in the magnetic shielding effect.
【００２５】[0025]
【表３】 初期強度(G) 粉片の種類 量wt％ 100 50 10 実施例 Ｃ1 Ａ1 (Ag 20％) 75 19.3 14.0 3.8 Ｃ2 Ａ2 (Ag 30％) 75 21.0 14.8 4.4 Ｃ3 Ａ3 (Ag 50％) 75 24.1 16.9 5.3 Ｃ4 Ｂ1 (Ag 30％) 75 21.5 15.1 4.6 Ｃ5 Ｂ2 (Ag 10％) 75 18.5 13.2 3.4 Ｃ6 Ｂ3 (Ni 20％) 75 19.2 13.9 3.8 Ｃ7 Ｂ4 (Cu 20％) 75 19.3 14.1 3.7 Ｃ8 Ａ4 (Ag 75％) 75 24.7 17.3 5.8 Ｃ9 Ａ5 (Ag 5％) 75 19.1 13.8 3.5 比較例 Ｃ11 Ａ6 （被覆なし）75 19.0 13.5 3.2 Ｃ12 （銀粉混合） 75 52.2 28.4 8.2 [Table 3] Initial strength (G) Types of powder pieces wt% 100 50 10 Example C1 A1 (Ag 20%) 75 19.3 14.0 3.8 C2 A2 (Ag 30%) 75 21.0 14.8 4.4 C3 A3 (Ag 50%) 75 24.1 16.9 5.3 C4 B1 (Ag 30%) 75 21.5 15.1 4.6 C5 B2 (Ag 10%) 75 18.5 13.2 3.4 C6 B3 (Ni 20%) 75 19.2 13.9 3.8 C7 B4 (Cu 20%) 75 19.3 14.1 3.7 C8 A4 (Ag 75%) 75 24.7 17.3 5.8 C9 A5 (Ag 5%) 75 19.1 13.8 3.5 Comparative example C11 A6 (without coating) 75 19.0 13.5 3.2 C12 (silver powder mixture) 75 52.2 28.4 8.2
【００２６】実施例４ 実施例３の本発明に係る試料(C1,C2) を用い、また比較
試料として従来のシールド粉末を混合した実施例３の試
料(C11) を用い、これらの試料について10〜1000MHz の
周波数領域における電磁波シールド効果を測定した。さ
らに参考のため、鱗片状の銀粉末（平均粒径15μm 、ア
スペクト比30、Ag:98wt ％）を用い、実施例３と同様に
して成形した板材（Ag粉片75wt％、試料No.C13）につい
て、その電磁波シールド効果を測定した。測定はアドバ
ンテスト法によって行い、電磁波シールド効果の評価器
に試料の成形板を設置し、スペクトラムアナライザーに
よって平面波の電磁波シールド効果を測定した。これら
の測定結果を図２に示す。なおシールド効果（単位dB）
は次式によって与えられる。 ２０ log[I0 ]/[I] ここで、Ｉ0 は試料を設置しないときの測定強度、Ｉは
試料を設置したときの測定強度である。Example 4 Samples (C1, C2) according to the present invention of Example 3 were used, and a sample (C11) of Example 3 in which a conventional shield powder was mixed was used as a comparative sample. The electromagnetic wave shielding effect in the frequency range of up to 1000MHz was measured. For further reference, a plate material (Ag powder flakes 75 wt%, sample No. C13) molded in the same manner as in Example 3 using scaly silver powder (average particle size 15 μm, aspect ratio 30, Ag: 98 wt%). The electromagnetic wave shielding effect was measured. The measurement was performed by the Advantest method, the molded plate of the sample was installed in the electromagnetic wave shielding effect evaluator, and the electromagnetic wave shielding effect of the plane wave was measured by the spectrum analyzer. The results of these measurements are shown in FIG. Shield effect (unit: dB)
Is given by 20 log [I 0 ] / [I] Here, I 0 is the measured intensity when the sample is not installed, and I is the measured intensity when the sample is installed.
【００２７】実施例５ 図３に示すように、１片が300mm の正六面体の試料箱ａ
を作り、その下面の中央に設けた小孔ｂを通じて試料箱
の中心に磁気センサーｃを導入し、これをガウスメータ
ｄに接続し、一方、試料箱ａの両側に一対のヘルムホル
ツコイルｅを設置し、これを波形発生装置ｆに接続し、
ガウスメータｄと波形発生装置ｆをＦＦＴアナライザｇ
に接続して電磁波シールド効果の測定系を形成した。こ
の測定系において、試料箱ａとヘルムホルツコイルｅの
距離を一定にし、波形発生装置ｆによって任意の周波数
の電圧をコイルｅに加え、該コイルｅに交流磁場による
電磁波を発生させ、この電磁波が試料箱内部に透過した
強度をセンサーｃによって測定し、試料箱による電磁波
シールド効果（減衰率％）が求められる。実施例４の試
料(C1,C2,C11,C13) について、上記測定装置によって求
めた電磁波シールド効果を図４に示した。なお、減衰率
％は次式で求めた。 ［Ｇ1 −Ｇ2 ］／Ｇ1 ×100 （％） ここで、Ｇ1 はコイルｅで発生した磁気強度（初期強
度）であり、Ｇ2 はセンサーｃで感知した磁気強度であ
る。Example 5 As shown in FIG. 3, a regular hexahedron sample box a with 300 mm pieces is used.
, A magnetic sensor c is introduced into the center of the sample box through a small hole b provided at the center of the lower surface, and this is connected to a Gauss meter d, while a pair of Helmholtz coils e are installed on both sides of the sample box a. , Connect it to the waveform generator f,
The Gauss meter d and the waveform generator f are connected to the FFT analyzer g.
To form a measurement system for electromagnetic wave shielding effect. In this measurement system, the sample box a and the Helmholtz coil e are kept at a constant distance, a voltage of an arbitrary frequency is applied to the coil e by a waveform generator f, and an electromagnetic wave due to an alternating magnetic field is generated in the coil e. The intensity transmitted through the inside of the box is measured by the sensor c, and the electromagnetic wave shielding effect (attenuation rate%) by the sample box is obtained. FIG. 4 shows the electromagnetic wave shielding effect of the samples (C1, C2, C11, C13) of Example 4 obtained by the above measuring device. The attenuation rate% was calculated by the following formula. [G1 -G2] / G1 x 100 (%) Here, G1 is the magnetic intensity (initial intensity) generated in the coil e, and G2 is the magnetic intensity sensed by the sensor c.
【００２８】実施例３に示すように、静磁場において
は、本発明の粉片を用いたシールド材(C1 〜C9) は従来
の金属被覆を有しない軟磁性粉片を用いたシールド材(C
11) をやや下回る程度のほぼ同等の磁気シールド効果を
有する。一方、交流磁場では図４に示すように、従来の
軟磁性粉片を用いたシールド材(C11) の減衰率は、１MH
z 以下の低周波域においては本発明の粉片を用いたシー
ルド材(C1,C2) よりやや上回るが１MHz 付近から次第に
減衰率（遮蔽効果）が大幅に低下し始め、図２のよう
に、１０MHz 以上の高周波域では逆に本発明の粉片を用
いたシールド材(C1,C2) のシールド効果が従来の軟磁性
粉片を用いたシールド材(C11) よりも格段に優れる。ま
た銀粉片を用いたシールド材(C13) についてみると、１
０MHz 以上の高周波域では本発明の粉片(C1,C2) をやや
上回るシールド効果を示すが、１０〜１MHz の低周波域
からシールド効果が極端に低下し１MHz 以下の低周波域
になると殆どシールド効果が得られない。一方、本発明
の粉片を用いたシールド材は上記各実施例に示すよう
に、静磁場および低周波域から高周波域の交流磁場の幅
広い周波数領域において優れた電磁波シールド効果を有
する。As shown in Example 3, in a static magnetic field, the shield material (C1 to C9) using the powder piece of the present invention is the conventional shield material (C1 to C9) using the soft magnetic powder piece without metal coating.
It has a magnetic shield effect that is slightly less than 11). On the other hand, in the alternating magnetic field, as shown in Fig. 4, the attenuation factor of the conventional soft magnetic powder piece (C11) is 1MH.
In the low frequency range of z or less, it is slightly higher than the shield material (C1, C2) using the powder of the present invention, but the attenuation rate (shielding effect) starts to significantly decrease from around 1 MHz, and as shown in FIG. In the high frequency range of 10 MHz or higher, on the contrary, the shielding effect of the shield material (C1, C2) using the powder piece of the present invention is far superior to that of the conventional shield material (C11) using the soft magnetic powder piece. Looking at the shield material (C13) using silver dust pieces,
In the high frequency range of 0 MHz or higher, the shielding effect is slightly higher than that of the powder particles (C1, C2) of the present invention, but the shielding effect is extremely lowered from the low frequency range of 10 to 1 MHz, and almost shielded in the low frequency range of 1 MHz or lower. No effect. On the other hand, the shield material using the powder particles of the present invention has an excellent electromagnetic wave shielding effect in a wide frequency range of a static magnetic field and an alternating magnetic field from a low frequency range to a high frequency range, as shown in each of the above embodiments.
【００２９】[0029]
【発明の効果】本発明の電磁波シールド粉片は、静磁場
および低周波域から高周波域に至る幅広い周波数領域の
電磁波に対して優れたシールド効果を有する。しかも、
該粉片を配合してなるシールド樹脂組成物は加工性に優
れるので、電磁波を遮蔽する必要のある用途に幅広く使
用することができる。また塗料に配合することにより優
れた電磁波シールド効果を発揮するので、この塗料を用
いて製品を塗装することにより電磁波シールド効果に優
れた製品を容易に得ることができる。The electromagnetic wave shielding powder piece of the present invention has an excellent shielding effect against electromagnetic waves in a wide range of frequencies from static magnetic fields and low frequency regions to high frequency regions. Moreover,
Since the shield resin composition containing the powder pieces has excellent processability, it can be widely used in applications where it is necessary to shield electromagnetic waves. Further, since it exhibits an excellent electromagnetic wave shielding effect by being mixed with a paint, a product excellent in the electromagnetic wave shielding effect can be easily obtained by coating a product with this paint.
【図１】 静磁場での磁気シールド効果測定装置の概略
図。FIG. 1 is a schematic view of a magnetic shield effect measuring device in a static magnetic field.
【図２】 高周波域における電磁波シールド効果を示す
グラフ。FIG. 2 is a graph showing an electromagnetic wave shielding effect in a high frequency range.
【図３】 交流磁場での磁気シールド効果測定装置の概
略図。FIG. 3 is a schematic diagram of a magnetic shield effect measuring device in an alternating magnetic field.
【図４】 低周波域における電磁波シールド効果を示す
グラフ。FIG. 4 is a graph showing an electromagnetic wave shielding effect in a low frequency range.
６０−測定装置 ６４−磁石 ７０−磁気強度検出器 60-Measuring device 64-Magnet 70-Magnetic intensity detector
Claims (5)
電性金属が被覆されていることを特徴とする電磁波シー
ルド粉片。1. An electromagnetic wave shielding powder piece, characterized in that a soft magnetic powder piece having a high magnetic permeability and a low coercive force is coated with a conductive metal.
金、パーマロイ合金、Ｃｏ系ないしＦｅ系非晶質合金粉
片あるいはフェライト系酸化物粉片である請求項１の電
磁波シールド粉片。2. The electromagnetic shielding powder piece according to claim 1, wherein the soft magnetic powder piece is silicon steel, Sendust alloy, permalloy alloy, Co-based or Fe-based amorphous alloy powder piece or ferrite-based oxide powder piece.
金、パラジウムまたはこれらの合金である請求項１また
は２の電磁波シールド粉片。3. The conductive metal is copper, silver, nickel,
The electromagnetic wave shielding powder piece according to claim 1, which is gold, palladium or an alloy thereof.
５〜１０5 である請求項１〜３のいずれかの電磁波シー
ルド粉片。4. The electromagnetic wave shielding powder piece according to claim 1, which has an average particle diameter of 1 μm to 5 cm and an aspect ratio of 5 to 10 5 .
０〜５０のＦｅ系非晶質合金粉片に、銅、銀またはニッ
ケルが被覆粉片の５〜７５重量％被覆されている請求項
１の電磁波シールド粉片。5. An average particle diameter of 5 to 200 μm and an aspect ratio of 1.
The electromagnetic shielding powder piece according to claim 1, wherein the Fe-based amorphous alloy powder piece of 0 to 50 is coated with copper, silver or nickel in an amount of 5 to 75% by weight of the coated powder piece.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5345685A JPH07183110A (en) | 1993-12-22 | 1993-12-22 | Electromagnetic wave shielding powder piece |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5345685A JPH07183110A (en) | 1993-12-22 | 1993-12-22 | Electromagnetic wave shielding powder piece |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07183110A true JPH07183110A (en) | 1995-07-21 |
Family
ID=18378277
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5345685A Withdrawn JPH07183110A (en) | 1993-12-22 | 1993-12-22 | Electromagnetic wave shielding powder piece |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07183110A (en) |
Cited By (7)
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|---|---|---|---|---|
| JP2002198239A (en) * | 2000-12-25 | 2002-07-12 | Hioki Ee Corp | Method of manufacturing magnetic body, the magnetic body, and cable |
| JP2006134907A (en) * | 2004-11-02 | 2006-05-25 | Dowa Mining Co Ltd | Radio wave absorber material and radio wave absorber |
| JP2006286729A (en) * | 2005-03-31 | 2006-10-19 | Kobe Steel Ltd | Paint composition excellent in electromagnetic wave absorbency and conductivity, and coated metal plate coated therewith |
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1993
- 1993-12-22 JP JP5345685A patent/JPH07183110A/en not_active Withdrawn
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002198239A (en) * | 2000-12-25 | 2002-07-12 | Hioki Ee Corp | Method of manufacturing magnetic body, the magnetic body, and cable |
| JP2006134907A (en) * | 2004-11-02 | 2006-05-25 | Dowa Mining Co Ltd | Radio wave absorber material and radio wave absorber |
| JP4714841B2 (en) * | 2004-11-02 | 2011-06-29 | Ｄｏｗａエレクトロニクス株式会社 | Radio wave absorber material and radio wave absorber |
| JP2006286729A (en) * | 2005-03-31 | 2006-10-19 | Kobe Steel Ltd | Paint composition excellent in electromagnetic wave absorbency and conductivity, and coated metal plate coated therewith |
| US10827660B2 (en) | 2015-10-27 | 2020-11-03 | Henkel IP & Holding GmbH | Conductive composition for low frequency EMI shielding |
| KR20180075580A (en) * | 2015-10-27 | 2018-07-04 | 헨켈 아게 운트 코. 카게아아 | Conductive composition for low frequency EMI shielding |
| US20180249603A1 (en) * | 2015-10-27 | 2018-08-30 | Henkel IP & Holding GmbH | Conductive composition for low frequency emi shielding |
| JP2019500742A (en) * | 2015-10-27 | 2019-01-10 | ヘンケル・アクチェンゲゼルシャフト・ウント・コムパニー・コマンディットゲゼルシャフト・アウフ・アクチェンＨｅｎｋｅｌ ＡＧ ＆ Ｃｏ． ＫＧａＡ | Conductive composition for low frequency EMI shielding |
| TWI769992B (en) * | 2015-10-27 | 2022-07-11 | 德商漢高股份有限及兩合公司 | A conductive composition for low frequency emi shielding |
| CN108620576A (en) * | 2017-03-20 | 2018-10-09 | 中国科学院宁波材料技术与工程研究所 | A kind of highly conductive amorphous soft magnet coating |
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| CN111033646A (en) * | 2017-08-03 | 2020-04-17 | 保德科技股份有限公司 | Composite particle, powder, resin composition, and molded body |
| WO2019027023A1 (en) * | 2017-08-03 | 2019-02-07 | パウダーテック株式会社 | Composite particles, powder, resin composition and moulded body |
| WO2020158520A1 (en) * | 2019-01-29 | 2020-08-06 | パウダーテック株式会社 | Electrode-forming material, method for producing electrode, and electrode |
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