JPS604569A - Paint for shielding electromagnetic radiation - Google Patents

Abstract

PURPOSE:To provide a paint having remarkably improved effect to shield electromagnetic radiation, and to enable the use of a plastic to the casing of electronic apparatus, by using a filler obtained by mixing Ni powder and fine graphite powder at a specific ratio. CONSTITUTION:The objective paint is obtained by mixing a paint made of synthetic resin, etc. with a filler obtained by mixing (A) Ni powder (preferably carbonyl Ni powder having an average particle diameter of <=5mu or flaky Ni powder having an average particle diameter of <=80mu) and (B) graphite powder having an average particle diameter of <=10mu or its mixture with carbon black having an average particle diameter of <=1mu, at a weight ratio of 99.5:0.5-80:20.

Description

【発明の詳細な説明】 電子機器の筺イホは従来はと／υと金属製であったが、
別器の小型・軽量化指向ならびにコストの而から、次第
にプラスチック製に代えられ−Ｃいる。[Detailed Description of the Invention] Traditionally, the housings of electronic devices were made of metal.
Due to the desire to reduce the size and weight of separate containers as well as cost considerations, they are gradually being replaced by plastic ones.

１ノかしこれに伴い、電磁波の漏れが問題になつ−Ｃき
１こ。However, along with this, leakage of electromagnetic waves becomes a problem.

即ら筐体が金属製の場合は、筐体白身が電磁波を吸収お
よび反則して、筐体内外の電磁波を遮断していたのに対
して、筐体がブラスヂシクの場合は、プラスデックが電
磁波を透過させるために、１穴器が発生するＷｉ　ｌ！
波を外部に漏らし、あるいは外部の電磁波を筐体内に侵
入させてしまう。In other words, when the housing is made of metal, the white body of the housing absorbs and counteracts electromagnetic waves, blocking electromagnetic waves inside and outside the housing, whereas when the housing is made of brass, the plus deck blocks electromagnetic waves. A one-hole device is generated to transmit Wi l!
This may cause waves to leak to the outside or allow external electromagnetic waves to enter the housing.

電子機器はそれぞれ特定周波数の電磁波により誤動作を
起こり。従って、プラスチック製筐体に電磁波シールド
処理りる必要が出（きた。Electronic devices malfunction due to electromagnetic waves of specific frequencies. Therefore, it has become necessary to apply electromagnetic shielding treatment to the plastic housing.

プラスチックの電磁波シールド処理には、プラスチック
内部に＞９電性フイラーを混合してプラスチック自体に
シールド性をもたせる方法と、ブラスヂックの表面にシ
ールド祠をイ」着させる方法とかある。現在は後者が主
流であり、金属フ２ｒルム（△ｌ　、Ｃｕ　、Ｆｅなど
）を貼る方法や、′金属溶用（Ｚｌｌ＞、メッキ、導電
性塗料の塗イｂににる導電性被膜の形成などがある。。There are two methods of electromagnetic shielding for plastics: one is to mix >9 conductive filler inside the plastic to give the plastic itself shielding properties, and the other is to attach a shielding stone to the surface of the plastic. Currently, the latter method is the mainstream, and there are methods for pasting metal films (△l, Cu, Fe, etc.), metal dissolution (Zll), plating, and conductive film coating on conductive paint. There are formations, etc.

本発明は、この内の導電性塗料に関づるものであって、
Ｎ１粉末と合成樹脂からなる導電性塗料に７Ｊ−ボンブ
ラックｉＪ３　Ｊ：び黒鉛を配合りることにより電磁波
シールド効果を茗しく改善づることを９、°ｉ徴どりる
ものである。The present invention relates to a conductive paint among these,
It is proposed that the electromagnetic shielding effect will be significantly improved by blending 7J-Bonblack iJ3 J: and graphite into a conductive paint made of N1 powder and synthetic resin.

以下、この発明を実施例について説明づる。Hereinafter, this invention will be explained with reference to embodiments.

試料の作成：先ず、右（幾）Ｒ剤５０部と合成（δｌ脂
１８部の溶液に平均粒径２．５μのカーボニルＮ１わ）
９８部と、平均粒径０．１μのカーボンブラック２部を
配合してボールミル中でｄ〜和し、第１表に示Ｊ’　Ｎ
　Ｏ，１の組成のｍ　Ｉ＋を作成した。同様にしＣ塗料
Ｎ　Ｏ，２〜Ｎ０．９を作成しＩＣ。Preparation of sample: First, synthesize with 50 parts of the right R agent (1 carbonyl N with an average particle size of 2.5μ in a solution of 18 parts of δl fat)
98 parts and 2 parts of carbon black with an average particle size of 0.1 μm were mixed in a ball mill to form J'N shown in Table 1.
m I+ having a composition of O,1 was prepared. In the same way, C paints NO.2 to N0.9 were prepared and IC was applied.

また、比較のために、カーボンブラックｄ３よび黒鉛を
含まない塗料（Ｎ　Ｏ，１０）および金属成分を含まな
い塗料（Ｎｏ、１１）を作成した。For comparison, a paint (No. 10) containing no carbon black d3 or graphite and a paint (No. 11) containing no metal components were prepared.

１１ １１１〜１１　″′　１　富１　１１−３＋Ｉｌｌ　ｌ
　１１寸１ ｉ　ｌ”Ｉヨ　、、ｉ　ｌ１１ １１のｌ ｌ１ｌ　ｌ　１１寸１ １け　ｌ　ｌ　１１１ 次に、これらの塗Ｒ（Ｎ　０．１〜１１）それそ゛れを
人ぎさ１５０Ｘ　１５０ｘ　２１１１ｍのＡ　１３　Ｓ
樹脂板に乾燥ｊ般の膜厚が５０μになるように塗布し、
２４時間自然乾燥したものを試料Ｎ　０．１〜Ｎ０．１
１とした。11 111~11 ″′ 1 wealth 1 11-3+Ill l
11 dimensions 1 i l"Iyo,, i l11 11's l l1l l 11 dimensions 1 1 digit l l 111 Next, apply these coatings R (N 0.1 to 11) and all of them to A 13 of 150 x 150 x 2111 m. S
Apply it to a resin plate so that the dry film thickness is 50μ,
Samples N0.1 to N0.1 were air-dried for 24 hours.
It was set to 1.

なお、試料Ｎ　Ｏ，は塗ねＮ　Ｏ，に対応させである。Note that sample NO, corresponds to coating NO,.

シールド効果の測定：所定の間１ｔｌｉｌて配置されＩ
Ｃ一対のアンテナの中間の位同に、アンテナを結７ス直
線とその面が垂直になるＪ、うに樹脂板をｒｌい−Ｃ）
７ンデナの一方から電磁波を発信し、他方で受信される
（樹脂板に塗イｌｊ　シた塗わ１の種類に応じて減衰さ
れた）電磁波の強度を測定する方法で行なった。各試料
の減衰度を第１表のシール１へ効果の欄に、また、これ
をグラフ化しで第１図に示した。Measurement of shielding effectiveness: I
C) Connect the antenna at the midpoint of the pair of antennas so that the plane is perpendicular to the 7th line.
This was done by emitting electromagnetic waves from one side of the 7-band antenna and measuring the intensity of the electromagnetic waves received from the other side (attenuated depending on the type of coating 1 applied to the resin plate). The degree of attenuation of each sample is shown in the column of effect on seal 1 in Table 1, and this is shown in a graph in FIG.

なお、樹脂板がブランク即ら塗オ′」を塗イｌｉ　シ’
ｒ　ｌ、ｔい場合は、減衰度はＯデシベル（゛ある。Note that if the resin plate is blank, do not apply the coating.
If r l,t is low, the degree of attenuation is O decibel (゛).

以上の実験結果から、次のことが判る。先ず、黒鉛など
の中味と金Ｊ爪粉では、後者の方か優れＣいるか、それ
でも減衰度は３０デシベルに過ぎない。しかるに金属粉
に少量の黒鉛などを添加づるど、ぞの減衰１印は急激に
向−１−シて５０デシベルに達づる。From the above experimental results, the following is understood. First of all, between the content of graphite and gold J nail powder, the latter is better, but the attenuation is still only 30 decibels. However, when a small amount of graphite is added to the metal powder, the attenuation mark of 1 suddenly shifts to -1- and reaches 50 decibels.

この効果は金属粉に対重る添加量がと＜　ｉｔ’ｖかな
９９．５：０．５以上で有意となり、９８；２のイ・」
近で極大値に達し、添加量がさらに増えると減少の傾向
を示し、７０：３０では金属粉単味より劣る減衰度（２
５デシベル）しか得られる１い。ぞこＣ添加の効果が確
実に大ぎい範囲として、添加量の上限を８０　：　２０
に停めるのか適当Ｃある。This effect becomes significant when the amount added relative to the metal powder is 99.5:0.5 or more, and 98;
It reaches a maximum value at 70:30, and as the amount added further increases, it shows a decreasing tendency, and at 70:30, the attenuation is inferior to that of metal powder alone (2
5 decibels). The upper limit of the amount added is set at 80:20 to ensure that the effect of adding Zoko C is large.
Is it appropriate to park at C?

なお黒鉛とカーボンブラックとを比較りると、後者の方
が多少その効果が人きくなっ（いるが、実用上はそのい
ずれを用いてもよく、適宜の割合ｒ　（７１川しても差
し支えない。また、塗料が長期間安定した懸濁状態を保
ち、且つ強固な塗１１！、！を作るためには塗料組成中
の固体粒子を微細化づる必要があり、Ｎ１粉は平均粒径
５μ以下、黒鉛′ｒ５）末は１０μ以下、カーボンブラ
ックは１μ以−１・ぐあることが望ましい。Comparing graphite and carbon black, the latter has a slightly better effect (although in practice either of them may be used, and an appropriate proportion r (71%) is acceptable. In addition, in order for the paint to maintain a stable suspended state for a long period of time and to create a strong coating11!,!, it is necessary to make the solid particles in the paint composition finer, and N1 powder has an average particle size of 5μ or less. It is desirable that the graphite powder has a diameter of 10μ or less, and that the carbon black has a diameter of 1μ or more.

以上に；ホべた如く、本発明に係る塗オ′３１はかなり
効果的に電磁波を遮断することかＣきるため、本発明の
採用により電子機器の筺体をプラスチック化りることが
可能どなり、機器の軽Ｉ′ｉ）化ならびにコスト低減に
及ばず影響・効果は極めて大きい。As mentioned above, the coating according to the present invention can block electromagnetic waves quite effectively, so by adopting the present invention, it is possible to make the housing of electronic equipment into plastic, and the The impact and effects are far greater than the reduction in weight (I'i) and cost reduction.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図はＮ１粉に苅り−る黒鉛粉Ｊたはカーボンブラッ
クの添加量と電磁波シールド効果どの関係を示づグラフ
である。 代理人　増　渕　邦　彦 第１図FIG. 1 is a graph showing the relationship between the amount of graphite powder or carbon black added to the N1 powder and the electromagnetic shielding effect. Agent Kunihiko Masubuchi Figure 1

Claims (1)

【特許請求の範囲】 １　Ｎ１粉末と平均粒径１０μ以下の黒鉛粉末とが９９
．５：０．５〜８０　：　２０の割合に配合されたフィ
ラーを用いることを特徴とＪる電磁波シールド塗料。 ２　Ｎｉ粉末と平均粒径１μ以下のノＪ−ボンブラック
とが９９．５：０．５−８０：２０の割合に配合された
フィラーを用いることを特徴どＪる電磁波シールド塗料
。 ３　Ｎｌ粉末ど、平均粒径１０μ以下の黒鉛粉末おＪ：
び平均粒径１μ以下のカーボンブラックとの混合粉が９
９：５：０．５〜８０　：　２０の割合に配合されたフ
ィラーを用いることを特徴とりる電磁波シールド塗料。 ４　Ｎｉ粉末として平均粒径５μ以下のカーボニルＮ１
わ）を用いる特許′「請求の範囲第１項、第２項または
第３項の塗料。 ５ＮｉＦ＞）末として平均粒径５０μ以下のフレーク状
Ｎｉ粉を用いる特許請求の範囲第１１ｐ、第２項または
第３項の塗料。[Claims] 1 N1 powder and graphite powder with an average particle size of 10μ or less are 99%
．． An electromagnetic shielding paint characterized by using a filler blended in a ratio of 5:0.5 to 80:20. 2. An electromagnetic shielding paint characterized by using a filler in which Ni powder and J-bon black having an average particle size of 1 μm or less are blended in a ratio of 99.5:0.5 to 80:20. 3 Nl powder, graphite powder with an average particle size of 10μ or less:
Mixed powder with carbon black with an average particle size of 1μ or less
An electromagnetic shielding paint characterized by using a filler blended in a ratio of 9:5:0.5 to 80:20. 4 Carbonyl N1 with an average particle size of 5μ or less as Ni powder
5NiF>) A patent using flaky Ni powder with an average particle size of 50μ or less as a powder; Claims 11p and 2 Paints in Section 3 or Section 3.