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JPH03268398A - Pellet for electromagnetic shield molding and manufacture of enclosure of electromagnetic shield type - Google Patents

Pellet for electromagnetic shield molding and manufacture of enclosure of electromagnetic shield type

Info

Publication number
JPH03268398A
JPH03268398A JP6779090A JP6779090A JPH03268398A JP H03268398 A JPH03268398 A JP H03268398A JP 6779090 A JP6779090 A JP 6779090A JP 6779090 A JP6779090 A JP 6779090A JP H03268398 A JPH03268398 A JP H03268398A
Authority
JP
Japan
Prior art keywords
metal fibers
electromagnetic shield
intertwined
length
shielding effect
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.)
Pending
Application number
JP6779090A
Other languages
Japanese (ja)
Inventor
Shigeru Kashiwazaki
柏崎 茂
Hideki Asano
秀樹 浅野
Shinkichi Nakagawa
中川 真吉
Toshio Kosone
小曽根 敏雄
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
TOYO SHINDOUSHIYO KK
Hitachi Cable Ltd
Original Assignee
TOYO SHINDOUSHIYO KK
Hitachi Cable Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by TOYO SHINDOUSHIYO KK, Hitachi Cable Ltd filed Critical TOYO SHINDOUSHIYO KK
Priority to JP6779090A priority Critical patent/JPH03268398A/en
Publication of JPH03268398A publication Critical patent/JPH03268398A/en
Pending legal-status Critical Current

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  • Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)

Abstract

PURPOSE:To maintain a molding working property and a shielding effect at a high degree by a method wherein the whole or one part of a group of metal fibers whose outside diameter corresponds to 20 to 200mum and which are intertwined mutually in the length direction is covered with a plastic and it is cut to a length of 5 to 20mm. CONSTITUTION:Metal fibers whose outside diameter corresponds to 20 to 200mum are intertwined mutually in the length direction; the whole or one part of a group of the metal fibers is covered with a plastic; and it is cut to a length of 5 to 20mm to be pelletized. As a manufacturing means of the metal fibers to be intertwined, nothing is specified. As a preferable method to be recommended, the following method is suitable: a metal thin sheet is wound on a mandrel; the mandrel is turned; a cutting tool is installed at its edge and is fed; and the metal fibers whose cross section is a rectangular shape and which are intertwined loosely are manufactured. Thereby, a molding working property and a shielding effect can be maintained at a high degree.

Description

【発明の詳細な説明】 [産業上の利用分野] 本発明は、優れた電磁シールド効果を発揮し得るように
金属繊維が配置されてなる電磁シールド用ペレット及び
それを用い比較的安価にしかもシールド効果の高い電磁
シールド型筐体を製造するそれぞれの製造方法に関する
ものである。
Detailed Description of the Invention [Industrial Application Field] The present invention provides an electromagnetic shielding pellet in which metal fibers are arranged so as to exhibit an excellent electromagnetic shielding effect, and a relatively inexpensive shielding method using the same. The present invention relates to respective manufacturing methods for manufacturing highly effective electromagnetic shielding type casings.

[従来の技術] 近年における電子機器類の発達および普及は目覚ましい
ものがあり、益々高度化かつ精密化される傾向にある。
[Prior Art] The development and spread of electronic devices in recent years has been remarkable, and they are becoming increasingly sophisticated and precise.

それに伴い、これらの電子機器類に使用されている素子
群などから発生する電磁波が周辺機器に影響を及ぼし、
誤動作などの電磁波障害を生じさせる例がみられるよう
になり、最近にわかに問題視されるようになった。
Along with this, electromagnetic waves generated from the elements used in these electronic devices affect peripheral devices.
Recently, there have been cases of electromagnetic interference caused by malfunctions, and this has suddenly become a problem.

とくに、最近は装置の小型化および量産化が進み、各種
電子機器類の筐体が従来の金属からプラスチック成形品
に代って使用されるようになり、上記電磁波に対してい
わば無防備のような状態になっている。すなわち、プラ
スチックは金属に比較すると電磁波にとっては透明に等
しいものであリ、電磁放射が大きい上、外来電磁波も容
易に侵入することができる。
In particular, recently, devices have become more compact and mass-produced, and the housings of various electronic devices are now being replaced with plastic molded products instead of the conventional metal, making them virtually defenseless against the electromagnetic waves mentioned above. is in a state. That is, compared to metal, plastic is almost transparent to electromagnetic waves, and not only does it emit a large amount of electromagnetic radiation, but also foreign electromagnetic waves can easily penetrate into plastic.

そこでプラスチック成形品を電磁シールドするために、
成形品の表面に導電体層を設けることが行なわれている
。そのような手段として導電性塗料塗布、金属溶射、箔
の貼着、蒸着、スパッタリング、めっきなどがあるが、
いずれも面倒であり、大量生産には不向きである。
Therefore, in order to electromagnetically shield plastic molded products,
It is common practice to provide a conductive layer on the surface of a molded product. Such methods include conductive paint application, metal spraying, foil adhesion, vapor deposition, sputtering, and plating.
Both are troublesome and unsuitable for mass production.

このため、導電性をプラスチック材料自身に保有させる
ために、金属製のリボン、フレーク(細片)、パウダあ
るいはメタライズドガラス、カーボンブラック、カーボ
ンファイバなどの導電体をプラスチックに混合する方法
が注目され実施されるようになった。
For this reason, methods of mixing conductors such as metal ribbons, flakes, powders, metallized glass, carbon black, and carbon fibers into plastics have attracted attention and are being implemented in order to make the plastic materials themselves conductive. It started to be done.

[発明が解決しようとする課題] 上記導電体混合法のどれもが同じ特性を示すものではな
く、高いシールド効果を得るには混合導電体のアスペク
ト比(長さ方向に揃った状態を有する部片の比)が大き
く、かつ混合導電体の相互の接触状態が良好に保持され
、しかも成形するプラスチックの流動性を損わないこと
が必要である。
[Problems to be Solved by the Invention] None of the above conductor mixing methods exhibit the same characteristics, and in order to obtain a high shielding effect, the aspect ratio of the mixed conductor (parts that are aligned in the length direction) must be adjusted. It is necessary that the mixed conductors have a large cross-section ratio), that the mutual contact of the mixed conductors is maintained well, and that the fluidity of the plastic to be molded is not impaired.

このような要請に対応し得るものとして、最近は20μ
m径以下径大下ンレス鋼繊維を混合したシールド複合材
料が比較的多く使用されるようになった。
Recently, 20μ
Shielding composite materials that are a mixture of unrestrained steel fibers with a diameter of m or less have come to be used relatively often.

しかし、上記20μm径以下径大下き製造した極細ステ
ンレス繊維はかなり高価なものであり、成形品そのもの
が高価になってしまうという問題がある。
However, the ultra-fine stainless steel fibers produced with a diameter of 20 μm or less are quite expensive, and there is a problem in that the molded product itself becomes expensive.

また、このような極細ステンレス繊維のアスペクト比を
大きくしシールド効果を高めようとすると、ファイバー
ボールすなわち一種の毛玉状態となってしまい成形加工
性及びシールド性能が逆に低下してしまうという問題が
あった。
In addition, when attempting to increase the shielding effect by increasing the aspect ratio of such ultra-fine stainless fibers, there is a problem in that fiber balls, that is, a type of fluff, deteriorate moldability and shielding performance. there were.

本発明の目的は、上記したような従来技術の問題点を解
消し、アスペクト比を高く維持し、金属繊維間の接触状
態も良好に保持することができ、ファイバーボールの形
成がなく従って成形加工性やシールド効果を高度に維持
可能な電磁シールド成形用ペレット及びそれを用いた電
磁シールド型筐体のそれぞれの製造方法を提供しようと
するものである。
The purpose of the present invention is to solve the problems of the prior art as described above, to maintain a high aspect ratio, to maintain good contact between metal fibers, and to eliminate the formation of fiber balls. The object of the present invention is to provide pellets for forming electromagnetic shields that can maintain high properties and shielding effects, and methods for producing electromagnetic shielding type casings using the pellets.

[課題を解決するための手段] 本発明は、第1に、外径相当において20〜200μm
の金属繊維が長さ方向に相互に絡み合わせられ、当該絡
み合わせられた金属繊維群の全体あるいは一部にプラス
チックが被覆せられ、長さ5〜20mに切断されペレッ
ト化されてなるものであり、第2に、かかるペレットを
射出成形機内に投入して加熱押出しすることにより、金
属繊維のアスペクト比を高くしかつ金属繊維相互間の接
触状態を良好に保持して射出成形することにより筐体を
成形するものである。
[Means for Solving the Problems] The present invention firstly provides an outer diameter equivalent to 20 to 200 μm.
metal fibers are intertwined with each other in the length direction, the entangled metal fibers are entirely or partially covered with plastic, and are cut into lengths of 5 to 20 m and pelletized. Second, the pellets are put into an injection molding machine and heated and extruded to increase the aspect ratio of the metal fibers and maintain good contact between the metal fibers. It is used to mold.

外径相当すなわち円形断面のものも含むが非円形断面の
ものであってもよく、円形断面にした場合の換算外径が
20〜200μmの絡み合い金属繊維を製造し得れば、
その製造手段としてはとくに特定はしない、従って得ら
れた結果が円形断面であっても非円形断面であっても差
支えはない。
It includes those with an outer diameter equivalent to that of a circular cross section, but it may also have a non-circular cross section, and if it is possible to produce entangled metal fibers with an equivalent outer diameter of 20 to 200 μm when the cross section is made into a circular cross section,
The manufacturing method is not particularly specified; therefore, it does not matter whether the obtained result has a circular cross section or a non-circular cross section.

しかし、推奨する好ましい方法としては、金属の薄板を
マンドレルに巻付けて回転させ、その端面に切削工具を
設置してこれを送ることにより断面長方形のゆるい絡み
合いを有する金属繊維を製造する方法が適当である。上
記の相当外径は、用いる金属薄板の厚さと切削工具の送
り速度によって調節することができる。以下これをコイ
ル切削法と呼ぶこととする。
However, the recommended and preferred method is to wind a thin metal plate around a mandrel and rotate it, set a cutting tool on the end face of the metal plate, and then feed it to produce loosely intertwined metal fibers with a rectangular cross section. It is. The above-mentioned equivalent outer diameter can be adjusted depending on the thickness of the thin metal plate used and the feed rate of the cutting tool. Hereinafter, this will be referred to as the coil cutting method.

金属繊維の外径範囲は、ファイバーボールの生成を制限
するために20μm以上が必要であり、少量の金属繊維
の添加で高いシールド効果を得るためには200μm以
下とすればよいことを実験によって見出した。金属繊維
を構成する材料としては導電性の上から銅又は銅合金が
好ましい。
Through experiments, we found that the outer diameter range of metal fibers needs to be at least 20 μm to limit the formation of fiber balls, and that it is sufficient to set it to 200 μm or less in order to obtain a high shielding effect with the addition of a small amount of metal fibers. Ta. As the material constituting the metal fiber, copper or a copper alloy is preferable from the viewpoint of electrical conductivity.

また、金属繊維をゆるく相互に絡み合わせることにより
極めて高いシールド効果が得られることも実験によって
見出した。後に詳述する通り、これによって本発明が特
徴とする良好な成形流動性、高いシールド性能の保持、
および経済性を実現することができるものである。
Additionally, it was discovered through experiments that an extremely high shielding effect can be obtained by loosely intertwining metal fibers with each other. As will be detailed later, this allows the present invention to maintain good molding fluidity and high shielding performance,
and can realize economic efficiency.

さらに、射出成形機内適したペレットとするためにプラ
スチックを被覆する。ペレットの長さは、シールド性能
を保つために5鎮以上が必要である。また、成形機のス
クリューへのくい込み性のM限から、ペレット長は20
rm以下とする必要がある。
Additionally, the pellets are coated with plastic to make them suitable for injection molding machines. The length of the pellet must be 5 or more in order to maintain shielding performance. In addition, from the M limit of the ability to penetrate into the screw of the molding machine, the pellet length is 20
It is necessary to keep it below rm.

一方、上記被覆をするプラスチックとしては、ABS樹
脂、ポリプロピレン(PP) 、ポリフェニレンスルフ
ィド(PPS)、ポリスチレン(PS)あるいはポリフ
ェニレンオキシド(PPO)などの汎用の成形用プラス
チックを適宜使用すればよい。
On the other hand, as the plastic for the coating, general-purpose molding plastics such as ABS resin, polypropylene (PP), polyphenylene sulfide (PPS), polystyrene (PS), or polyphenylene oxide (PPO) may be used as appropriate.

[実施例] 以下に、本発明について実施例を参照し説明する。[Example] The present invention will be described below with reference to Examples.

実施例1 前記コイル切削法により厚さ25μmの黄銅薄板を巾約
50μmに切削し繊維が相手に絡み合うように巻取った
。その結果、1本の繊維長が50〜80aaで平均約5
0本が相互に絡み合い、結果として連続した黄銅繊維束
を1000m得ることができた。この繊維を400本−
束として押出機により温度190℃でポリスチレンを肉
厚的0.3m+に被覆し、電線状とした0次いでペレタ
イザで切断し所定の長さの黄銅繊維入りペレットを得た
Example 1 A thin brass plate having a thickness of 25 μm was cut to a width of about 50 μm using the coil cutting method described above, and the cut piece was wound up so that the fibers were intertwined with each other. As a result, the length of each fiber was 50 to 80 aa, and the average length was about 5
As a result, 1000 m of continuous brass fiber bundles were obtained. 400 of these fibers
The bundle was coated with polystyrene to a thickness of 0.3 m+ at a temperature of 190° C. using an extruder, and then cut into the shape of an electric wire using a pelletizer to obtain pellets containing brass fibers of a predetermined length.

このペレットとポリスチレンペレットを所定量混合して
80を射出成形機及び板状キャビティを有する金型を用
いて230℃で成形した。射出成形は良好に行なうこと
ができた。その結果黄銅繊維を4,0体積%含む150
X150X2+mのシートを得た。
A predetermined amount of these pellets and polystyrene pellets were mixed and molded into 80 at 230° C. using an injection molding machine and a mold having a plate-shaped cavity. Injection molding was successful. As a result, 150% containing 4.0% by volume of brass fibers
A sheet of x150x2+m was obtained.

次に、一般に行なわれているシールドボックスとスペク
トラムアナライザ(いずれもアトパンテスト社製)を用
いて電界波と磁界波のシールド効果を測定した。
Next, the shielding effect of electric field waves and magnetic field waves was measured using a commonly used shield box and spectrum analyzer (both manufactured by Atopan Test Co., Ltd.).

第1表にその結果を示す。Table 1 shows the results.

ペレットの長さを変えた試料の200MH7における値
は長い方が高くなるが5〜20mのいずれも十分なシー
ルド効果を示している。
The values at 200MH7 for samples with different pellet lengths are higher as the pellet length increases, but all pellet lengths of 5 to 20 m show sufficient shielding effects.

比較例1 ペレット長さを3止と25n+nとした以外は実施例1
と同様の方法で黄銅繊維入りシートを作製した。シール
ド効果を測定した結果、第1表に示すように、3止では
十分な効果を得ることができなかった。2’zn+のペ
レットはスクリューにくい込まずシートを作製できなか
った。
Comparative Example 1 Example 1 except that the pellet length was 3 stops and 25n+n
A sheet containing brass fibers was prepared in the same manner as above. As a result of measuring the shielding effect, as shown in Table 1, a sufficient effect could not be obtained with 3 stops. The 2'zn+ pellets did not sink into the screw and a sheet could not be produced.

実施例2 黄銅繊維の外径を20μm及び150μmに変えて実施
例1と同様にして長さ7闇のペレットを得た。つぎに、
実施例1と全く同じ条件で黄IPJ繊維4、O体積%を
含む成形シートを作製し、シールド効果を測定した。
Example 2 Pellets with a length of 7 mm were obtained in the same manner as in Example 1 except that the outer diameter of the brass fibers was changed to 20 μm and 150 μm. next,
A molded sheet containing 4% by volume of yellow IPJ fibers and O was produced under exactly the same conditions as in Example 1, and the shielding effect was measured.

第2表にその結果を示した。The results are shown in Table 2.

外径20μm、150μmとも良好なシールド効果を示
している。
Both outer diameters of 20 μm and 150 μm show a good shielding effect.

比較例2 繊維外径を10μmと250μmとした以外は実施例2
と同様にして成形シートを作製し、シールド効果を測定
した。
Comparative Example 2 Example 2 except that the fiber outer diameter was 10 μm and 250 μm.
A molded sheet was prepared in the same manner as above, and the shielding effect was measured.

結果を同じく第2表に示した。The results are also shown in Table 2.

10μmの場合は繊維の固まり(前記したファイバーボ
ール)が生じ、また均一な分散が得られず十分なシール
ド効果が得られなかった。250μmの場合は、ファイ
バーボールは生じないが同一混和量(4,0体積%)で
はシールド効果が大きく低下してしまっている。
In the case of 10 μm, aggregation of fibers (the above-mentioned fiber balls) occurred, and uniform dispersion could not be obtained, so that a sufficient shielding effect could not be obtained. In the case of 250 μm, no fiber balls are formed, but the shielding effect is greatly reduced at the same mixing amount (4.0% by volume).

第 2 表 第 表 比較例3 繊維の絡み合いのない(従来公知の)外径50μmの黄
銅繊維を用いて実施例1と同様にして成形シートを作製
した。
Table 2 Comparative Example 3 A molded sheet was produced in the same manner as in Example 1 using (conventionally known) brass fibers with an outer diameter of 50 μm without fiber entanglement.

そのシールド効果の測定結果を実施例1の相当例と比較
して第3表に示した。
The measurement results of the shielding effect are shown in Table 3 in comparison with the corresponding example of Example 1.

繊維の絡み合いを有するベレ・/トが大きなシールド効
果を与えることがこの対比によってよくわかる。
This comparison clearly shows that the beret/t with entangled fibers provides a great shielding effect.

比較例4 ペレット長さ7市、外径10Jimのステンレス繊維の
ペレットを作製しステンレスか2及び4体積%の組成と
なるようにして射出成形を試みたが、粘度が高く均一な
成形シートを得ることができなかった。
Comparative Example 4 Stainless steel fiber pellets with a pellet length of 7 mm and an outer diameter of 10 mm were prepared and injection molding was attempted with a composition of 2 and 4% by volume of stainless steel, but a uniform molded sheet with high viscosity was obtained. I couldn't.

[発明の効果] 以」−説明した通り、本発明に係る製造方法によれば、
アスペクト比を高く維持し、金属m離間の接触状態も良
好に保持することができ、ファイバーボールの形成がな
く従って成形加工性やシールド効果を高度に維持可能な
電磁シールド成形用ペレットを提供できると共に、それ
を用いて電磁シールド効果の極めて良好な筐体を製造し
得るものであり、電磁波障害が大きな社会問題となりつ
つある今日、本発明の有する工業的価値は極めて大きな
ものがある。
[Effects of the Invention] As explained above, according to the manufacturing method of the present invention,
It is possible to provide pellets for electromagnetic shielding molding that can maintain a high aspect ratio and maintain a good contact state between metals, and that does not form fiber balls and can therefore maintain high moldability and shielding effect. Using the same, it is possible to manufacture a housing with extremely good electromagnetic shielding effect, and the present invention has extremely great industrial value in these days when electromagnetic interference is becoming a major social problem.

Claims (3)

【特許請求の範囲】[Claims] (1)外径相当において20〜200μmの金属繊維が
長さ方向に相互に絡み合わせられ、当該絡み合わせられ
た金属繊維群の全体あるいは一部にプラスチックが被覆
せられ、長さ5〜20mmに切断されてなる電磁シール
ド成形用ペレット。
(1) Metal fibers with an outer diameter of 20 to 200 μm are intertwined with each other in the length direction, and all or part of the intertwined metal fibers are covered with plastic, and the length is 5 to 20 mm. Cut pellets for electromagnetic shield molding.
(2)金属繊維が銅又は銅合金よりなる請求項1記載の
電磁シールド成形用ペレット。
(2) The pellet for forming an electromagnetic shield according to claim 1, wherein the metal fibers are made of copper or a copper alloy.
(3)前記請求項1又は2記載のペレットを射出成形機
内に投入して加熱押出しすることにより、金属繊維のア
スペクト比を高くしかつ金属繊維相互間の接触状態を良
好に保持して射出成形する電磁シールド型筐体の製造方
法。
(3) The pellets according to claim 1 or 2 are put into an injection molding machine and heated and extruded, thereby increasing the aspect ratio of the metal fibers and maintaining good contact between the metal fibers, thereby forming injection molding. A method for manufacturing an electromagnetic shield type casing.
JP6779090A 1990-03-16 1990-03-16 Pellet for electromagnetic shield molding and manufacture of enclosure of electromagnetic shield type Pending JPH03268398A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6779090A JPH03268398A (en) 1990-03-16 1990-03-16 Pellet for electromagnetic shield molding and manufacture of enclosure of electromagnetic shield type

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6779090A JPH03268398A (en) 1990-03-16 1990-03-16 Pellet for electromagnetic shield molding and manufacture of enclosure of electromagnetic shield type

Publications (1)

Publication Number Publication Date
JPH03268398A true JPH03268398A (en) 1991-11-29

Family

ID=13355101

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6779090A Pending JPH03268398A (en) 1990-03-16 1990-03-16 Pellet for electromagnetic shield molding and manufacture of enclosure of electromagnetic shield type

Country Status (1)

Country Link
JP (1) JPH03268398A (en)

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