JPH0358559B2 - - Google Patents
Info
- Publication number
- JPH0358559B2 JPH0358559B2 JP4493584A JP4493584A JPH0358559B2 JP H0358559 B2 JPH0358559 B2 JP H0358559B2 JP 4493584 A JP4493584 A JP 4493584A JP 4493584 A JP4493584 A JP 4493584A JP H0358559 B2 JPH0358559 B2 JP H0358559B2
- Authority
- JP
- Japan
- Prior art keywords
- electromagnetic shielding
- conductive filler
- molded product
- molded
- melting point
- 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.)
- Expired
Links
Landscapes
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
Description
［発明の技術分野］
本発明は導電性フイラーを含有する電磁波シー
ルド性組成物を使用する電磁波シールド成形品の
製造方法に関する。
［発明の技術的背景］
デジタル電子機器等から発生する電磁波をシー
ルドする目的で、これらの電子機器の電子回路を
電磁波シールド効果を有するケースで包囲するこ
とが行われている。
しかして、このようなケースとして、従来か
ら、金属粉、カーボン粉、金属箔、金属繊維、カ
ーボン繊維等の導電性フイラーが混和された電磁
波シールド性組成物により成形されたケースが、
生産性、経済性、軽量性等において優れているこ
とから多く用いられている。
［背景技術の問題点］
しかしながら、このようなケースでは、導電性
フイラーの熱膨張率がベースポリマーに比べて小
さいため、成形時に得られた導電性フイラー間の
接触が使用環境の温度変化により離れる現象が起
こり、電磁波シールド効果が低下するという問題
があつた。そのため、このようなケースは使用環
境が変化するような用途に使用した場合、信頼性
に乏しいという難点があつた。
［発明の目的］
本発明はこのような点に対処してなされたもの
で、いかなる使用環境が変化しても優れた電磁波
シールド効果を維持することのできる高信頼性、
高品質の電磁波シールド成形品の製造方法を提供
することを目的とする。
［発明の概要］
すなわち本発明の電磁波シールド成形品の製造
方法は、ベースポリマー中に表面に低融点金属層
を有する導電性フイラーを混和してなる電磁波シ
ールド性組成物を用いて所定の形状に成形し、し
かる後この成形体に通電して前記低融点金属層を
溶融させることを特徴としている。
本発明の電磁波シールド性組成物のベースポリ
マーとしては、熱可塑性樹脂、熱硬化性樹脂のい
ずれも使用可能であり、例えばポリスチレン、
ABS樹脂等のスチレン系樹脂、ポリエチレン、
ポリプロピレン等のオレフイン系樹脂、ポリカー
ボネート、ポリアミド、ポリエステル、エポキシ
樹脂、アクリル系樹脂等が例示される。
また、導電性フイラーとしては、銅、鉄、ニツ
ケル、アルミニウム、ステンレス等の金属繊維、
ガラス繊維、カーボン繊維等の表面に低融点金属
層を形成したものが適している。
上記繊維としては、直径５〜100μｍ程度のも
のが適しており、低融点金属としては半田が適し
ている。
なお本発明に使用する導電性フイラーは、上記
した繊維状のものに限定されるものではなく、用
途によつては箔状あるいは微粒子状のものも使用
可能である。
本発明に使用する電磁波シールド組成物は、前
記したポリマー中に前記した導電フイラーおよび
必要に応じて顔料その他の添加剤を均一に分散さ
せることにより得られる。
導電性フイラーの配合量は、使用する導電性フ
イラーの形状、サイズ等により異なるが、通常５
〜40重量％程度が適当である。
第１図はこのような導電性フイラー１の構造例
を示す要部斜視図で、金属繊維１ａの外周に半田
層１ｂが設けられている。
本発明方法においては、以上のような電磁波シ
ールド性組成物を用いて、例えば射出成形、圧縮
成型、注型等により所定の形状に成形し、しかる
後、第２図に示すような、成形品２の成形時に予
めインサートしておいた各通電用端子３間に交流
電圧を引加して半田層を溶融させ、互いに接触し
ている繊維相互を半田により一体に結合させる。
最適通電電流は、導電性フイラーのサイズおよび
配合量により異なるが、サイズおよび配合量によ
り異なるが、例えば外径５〜100μｍ、長さ５〜
10mmの短繊維のものを５〜40重量％程度配合した
組成物を用い電極間隙１〜10cmで電圧を引加する
場合には、２〜20Vで0.1〜10秒間程度通電する
ことにより、導電性フイラー表面の低融点金属例
えば半田が通電による発熱で溶融し、この半田層
を介して導電性フイラー間を確実に結合させるこ
とができる。
このようにして製造された電磁波シールド成形
品は、電子機器に装着されて使用された後も、環
境温度の変化により導電性フイラー間が離れて導
通が失われることもなく、長期にわたつて信頼性
の高い電磁波シールド効果を有する。
なお、通電のための電極は成形品成形後にタツ
ピングねじ等で設けるようにしてもよい。
［発明の実施例］
次に実施例について説明する。
実施例
ポリスチレン70重量％と直径20μｍのステンレ
ス繊維の外周に半田めつきを施した導電性フイラ
ー30重量％とを混合して電磁波シールド性組成物
を得た。次にこの組成物を射出成形機に供給して
予め金型内にインサートしておいた８個の通電用
端子と一体成形し、第２図に示した成型品と同形
状の射出成形品を得た。
なお、この成形品の寸法は、幅200mm、長さ300
mm、高さ50mm、肉厚３mmである。
次いで15Vの電流を各端子間に0.1秒ずつ通電
し、電磁波シールド成形品を製造した。
比較例
比較例として、導電性フイラーに、表面に半田
層のない直径20μのステンレス繊維を用いた以外
は実施例と同様にして射出成形を行ない電磁波シ
ールド成形品を製造した。なお、この場合電極の
埋設および通電は行なつていない。
以上の実施例および比較例で得られた電磁波シ
ールド成形品について、電磁波シールド効果の耐
熱特性を測定したところ次表に示す通りであつ
た。
[Technical Field of the Invention] The present invention relates to a method for producing an electromagnetic shielding molded article using an electromagnetic shielding composition containing a conductive filler. [Technical Background of the Invention] For the purpose of shielding electromagnetic waves generated from digital electronic devices and the like, electronic circuits of these electronic devices are surrounded by a case having an electromagnetic wave shielding effect. However, as for such cases, cases molded from electromagnetic shielding compositions mixed with conductive fillers such as metal powder, carbon powder, metal foil, metal fibers, and carbon fibers have conventionally been used.
It is widely used because of its excellent productivity, economy, and light weight. [Problems with the background technology] However, in such cases, the thermal expansion coefficient of the conductive filler is smaller than that of the base polymer, so the contact between the conductive fillers obtained during molding may separate due to temperature changes in the usage environment. There was a problem that this phenomenon occurred and the electromagnetic shielding effect deteriorated. Therefore, when such a case is used in an application where the usage environment changes, there is a problem of poor reliability. [Object of the Invention] The present invention has been made to address the above-mentioned problems, and provides high reliability that can maintain an excellent electromagnetic shielding effect no matter how the usage environment changes.
The purpose is to provide a method for manufacturing high-quality electromagnetic shielding molded products. [Summary of the Invention] That is, the method for producing an electromagnetic shielding molded article of the present invention involves forming an electromagnetic shielding composition into a predetermined shape using an electromagnetic shielding composition formed by mixing a conductive filler having a low melting point metal layer on the surface in a base polymer. The method is characterized in that the molded body is molded, and then electricity is applied to the molded body to melt the low melting point metal layer. As the base polymer of the electromagnetic shielding composition of the present invention, both thermoplastic resins and thermosetting resins can be used, such as polystyrene,
Styrenic resins such as ABS resins, polyethylene,
Examples include olefin resins such as polypropylene, polycarbonates, polyamides, polyesters, epoxy resins, and acrylic resins. In addition, conductive fillers include metal fibers such as copper, iron, nickel, aluminum, and stainless steel;
Suitable materials include glass fibers, carbon fibers, etc., with a low melting point metal layer formed on the surface. Suitable fibers have a diameter of about 5 to 100 μm, and solder is suitable as the low melting point metal. The conductive filler used in the present invention is not limited to the above-mentioned fibrous filler, but may also be used in the form of foil or fine particles depending on the application. The electromagnetic shielding composition used in the present invention can be obtained by uniformly dispersing the conductive filler described above and, if necessary, pigments and other additives in the polymer described above. The amount of conductive filler blended varies depending on the shape, size, etc. of the conductive filler used, but is usually 5.
Approximately 40% by weight is appropriate. FIG. 1 is a perspective view of a main part showing an example of the structure of such a conductive filler 1, in which a solder layer 1b is provided on the outer periphery of a metal fiber 1a. In the method of the present invention, the electromagnetic shielding composition described above is molded into a predetermined shape by, for example, injection molding, compression molding, casting, etc., and then a molded product as shown in FIG. An alternating current voltage is applied between the current-carrying terminals 3 inserted in advance at the time of molding 2, the solder layer is melted, and the fibers in contact with each other are integrally bonded by solder.
The optimum current to be applied varies depending on the size and blending amount of the conductive filler.
When applying a voltage with an electrode gap of 1 to 10 cm using a composition containing 5 to 40% by weight of 10 mm short fibers, conductivity can be improved by applying current at 2 to 20 V for 0.1 to 10 seconds. A low melting point metal such as solder on the surface of the filler is melted by heat generated by electricity, and the conductive fillers can be reliably bonded via this solder layer. Even after the electromagnetic shielding molded product manufactured in this way is installed in electronic equipment and used, the conductive filler will not separate due to changes in environmental temperature and conductivity will not be lost, and it will remain reliable for a long time. It has a highly effective electromagnetic shielding effect. Note that the electrode for energization may be provided with a tapping screw or the like after the molded product is molded. [Embodiments of the Invention] Next, embodiments will be described. Example An electromagnetic shielding composition was obtained by mixing 70% by weight of polystyrene and 30% by weight of a conductive filler which was soldered onto the outer periphery of stainless steel fibers having a diameter of 20 μm. Next, this composition was fed into an injection molding machine and integrally molded with eight current-carrying terminals that had been inserted into the mold in advance to produce an injection molded product having the same shape as the molded product shown in Figure 2. Obtained. The dimensions of this molded product are width 200mm and length 300mm.
mm, height 50mm, wall thickness 3mm. Next, a 15V current was passed between each terminal for 0.1 seconds to produce an electromagnetic shield molded product. Comparative Example As a comparative example, an electromagnetic shielding molded product was produced by injection molding in the same manner as in the example except that a stainless steel fiber with a diameter of 20 μm without a solder layer on the surface was used as the conductive filler. In this case, the electrodes were not buried and energized. Regarding the electromagnetic shielding molded products obtained in the above Examples and Comparative Examples, the heat resistance characteristics of the electromagnetic shielding effect were measured, and the results were as shown in the following table.
【表】
［発明の効果］
以上の実施例および比較例からも明らかなよう
に、本発明方法によれば、配合された導電性フイ
ラーが表面の低融点金属により互いに連結されて
電気的に一体化するので、使用環境の熱的変化が
原因で起こる電磁波シールド効果の経時的な低下
現象がなくなるので、使用環境いかんにかかわら
ず長期にわたつて優れた電子波シールド特性を保
持することの可能な電磁波シールド成形品を得る
ことができる。[Table] [Effects of the Invention] As is clear from the above Examples and Comparative Examples, according to the method of the present invention, the blended conductive fillers are connected to each other by the low melting point metal on the surface and are electrically integrated. This eliminates the phenomenon of deterioration of electromagnetic shielding effectiveness over time caused by thermal changes in the usage environment, making it possible to maintain excellent electronic shielding properties over a long period of time regardless of the usage environment. Electromagnetic shielding molded products can be obtained.
第１図は本発明方法の一実施例に使用される導
電性フイラーの構造を示す斜視図、第２図は本発
明方法により製造された電磁波シールド成形品の
一例を示す斜視図である。
１……導電性フイラー、１ａ……金属繊維、１
ｂ……半田層、２……成形体、３……通電用端
子。
FIG. 1 is a perspective view showing the structure of a conductive filler used in an embodiment of the method of the present invention, and FIG. 2 is a perspective view showing an example of an electromagnetic shielding molded product manufactured by the method of the present invention. 1... Conductive filler, 1a... Metal fiber, 1
b...Solder layer, 2...Molded body, 3...Electricity terminal.
Claims (1)
する導電性フイラーを混和してなる電磁波シール
ド性組成物を用いて所定の形状に成形し、しかる
後この成形体に通電して前記低融点金属層を溶融
させることを特徴とする電磁波シールド成形品の
製造方法。 ２ 低融点金属が半田である特許請求の範囲第１
項記載の電磁波シールド成形品の製造方法。 ３ 通電は、成形時に予めインサートしておいた
通電用端子に通電することにより行なわれる特許
請求の範囲第１項記載の電磁波シールド成形品の
製造方法。 ４ 導電性フイラーは直径５〜100μｍ、長さ５
〜10mmの短繊維からなる特許請求の範囲第１項な
いし第３項記載の電磁波シールド成形品の製造方
法。[Claims] 1. An electromagnetic shielding composition prepared by mixing a conductive filler having a low melting point metal layer on the surface in a base polymer is molded into a predetermined shape, and then the molded body is energized. A method for manufacturing an electromagnetic shielding molded product, comprising melting the low melting point metal layer. 2 Claim 1 in which the low melting point metal is solder
A method for producing an electromagnetic shielding molded product as described in . 3. The method for producing an electromagnetic shielding molded product according to claim 1, wherein the energization is carried out by energizing a current-carrying terminal inserted in advance during molding. 4 Conductive filler has a diameter of 5 to 100 μm and a length of 5
A method for manufacturing an electromagnetic shielding molded article according to claims 1 to 3, which comprises short fibers of ~10 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4493584A JPS60189294A (en) | 1984-03-09 | 1984-03-09 | Method of producing electromagnetic wave shielded molding product |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4493584A JPS60189294A (en) | 1984-03-09 | 1984-03-09 | Method of producing electromagnetic wave shielded molding product |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60189294A JPS60189294A (en) | 1985-09-26 |
| JPH0358559B2 true JPH0358559B2 (en) | 1991-09-05 |
Family
ID=12705332
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4493584A Granted JPS60189294A (en) | 1984-03-09 | 1984-03-09 | Method of producing electromagnetic wave shielded molding product |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60189294A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0749491B2 (en) * | 1987-04-07 | 1995-05-31 | 東芝ケミカル株式会社 | Conductive resin composition |
| JP5777376B2 (en) * | 2011-03-31 | 2015-09-09 | 内浜化成株式会社 | Conduction method between conductive resin and metal parts |
-
1984
- 1984-03-09 JP JP4493584A patent/JPS60189294A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60189294A (en) | 1985-09-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US2817048A (en) | Transistor arrangement | |
| US4882227A (en) | Conductive resin composition and molded product using the same | |
| US4722824A (en) | Method of joining green bodies prior to sintering | |
| JP4567691B2 (en) | Metal-plastic-hybrid and molded body produced from the hybrid | |
| EP0347597A3 (en) | Insulating electromagnetic shielding resin composition | |
| JPH07312498A (en) | Electromagnetic shielding molding material | |
| JPS6320270B2 (en) | ||
| JPS6351354B2 (en) | ||
| JPH0358559B2 (en) | ||
| DE3522084A1 (en) | Plastic composition which is an electrical insulator and a good heat conductor and contains aluminium powder particles as filler, and a process for the preparation thereof | |
| JP2000327815A (en) | Preparation of electroconductive track on plastic by laser energy | |
| JPH0647254B2 (en) | Conductive resin composition | |
| JPH02113068A (en) | Conductive thermoplastic resin composition | |
| JPH055264B2 (en) | ||
| JPS63211698A (en) | Electromagnetic shielding compound | |
| JPH0647255B2 (en) | Conductive resin composition | |
| JPH06315932A (en) | Conductive resin molded piece | |
| JP2523098B2 (en) | Conductive resin composition and molded article thereof | |
| JP2004047470A (en) | Conductive resin composition and method for producing resin molded article using the same | |
| JPH07122023B2 (en) | Conductive resin composition | |
| JPH0632713Y2 (en) | Electromagnetic wave shield case | |
| JP2523097B2 (en) | Conductive resin composition and molded article thereof | |
| JPS63235368A (en) | Electrically conductive resin composition and molded product thereof | |
| EP0674326A2 (en) | Electrical conductor having an insulation of plastic material | |
| JPH04146975A (en) | Conductive paste composition |