JPH0746629B2 - Positive resistance temperature coefficient heating element - Google Patents

Description

【発明の詳細な説明】 産業上の利用分野 本発明は、採暖器具及び、一般の加熱装置として有用な
発熱体の構成に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat collecting device and a structure of a heating element useful as a general heating device.

従来の技術 従来の正の抵抗温度係数をもつ（以下PTCと称す）発熱
体は、例えば特公昭57-43995号公報や特公昭55-40161号
公報に示されているような構成であり、一対の電極間の
PTC抵抗体のPTC特性により適宜な温度に自己制御されて
いるものであった。2. Description of the Related Art A conventional heating element having a positive temperature coefficient of resistance (hereinafter referred to as PTC) has a structure as shown in, for example, Japanese Patent Publication No. 57-43995 and Japanese Patent Publication No. 55-40161. Between the electrodes
It was self-controlled to an appropriate temperature by the PTC characteristics of the PTC resistor.

しかし、特に大きな電力密度が要求される場合において
は、発熱体自体の温度分布を一様にするために一対の電
極間方向の温度分布を良好にすることが不可欠であり、
その解決策として特開昭60-28195号公報や第６図に示す
ように１対の電極間距離を互いに接近させて構成する方
法が講じられた。第６図において1a,1bは互いに接近し
て設けられた一対の平行平板状電極であり、この間にPT
C抵抗体２を配することにより高出力のPTC発熱体を現出
することが可能となった。However, particularly when a high power density is required, it is essential to make the temperature distribution in the direction between the pair of electrodes good in order to make the temperature distribution of the heating element itself uniform.
As a solution to this problem, a method has been taken in which the distance between a pair of electrodes is made close to each other as shown in JP-A-60-28195 and FIG. In FIG. 6, 1a and 1b are a pair of parallel plate electrodes provided close to each other, and PT is provided between them.
By arranging the C resistor 2, it became possible to expose a high output PTC heating element.

発明が解決しようとする問題点 一般に、こうしたPTC抵抗体は長期的な耐熱により酸化
劣化し、一時は高抵抗化するか、最終的には結晶性樹脂
が劣化し正抵抗温度特性がなくなり、さらには低抵抗化
し、異常過熱、発火に至る危険性を有している。しか
し、一時高抵抗化した際に、ほとんど発熱しなくなって
いき、劣化としては安全である。しかしながらこのよう
な、金属電極体により両面よりPTC抵抗体を覆う構成に
あっては、金属電極体で覆われた部分の酸素ガス透過度
は０となるため、耐熱劣化はほとんどなくなる。一方、
金属電極体で覆われていない例えば第６図のPTC抵抗体
の端面部分などは外装材だけによる酸素ガス透過防止で
あり、金属電極体の覆われている部分と覆われていない
部分で耐熱劣化速度が大きくなってくる。そして、酸化
防止剤等の耐熱安定剤により耐熱劣化速度を遅くするこ
とはできても、金属電極体の有無の比ではない。このた
め、金属電極体の沿面部分だけが耐熱酸化し、一時高抵
抗化するが、金属電極体で覆われた部分は正常に発熱し
ており、この熱により、この沿面部分はさらに劣化が促
進され、ついには低抵抗下したり、亀裂が生じたりし
て、異常過熱、発火に至る危険性を有していた。このよ
うに、従来の第６図に示すようなPTC発熱体には、酸化
劣化速度の差により、安全性を損なう危険性を有してい
た。Problems to be Solved by the Invention Generally, such a PTC resistor is oxidatively deteriorated due to long-term heat resistance and temporarily becomes high in resistance, or finally the crystalline resin is deteriorated and the positive resistance temperature characteristic disappears. Has a low resistance, and there is a risk of abnormal overheating and ignition. However, when the resistance is temporarily increased, almost no heat is generated and it is safe as deterioration. However, in such a structure in which the PTC resistor is covered from both sides with the metal electrode body, the oxygen gas permeability of the portion covered with the metal electrode body becomes 0, and therefore the heat resistance deterioration hardly occurs. on the other hand,
For example, the end surface of the PTC resistor shown in Fig. 6 that is not covered with the metal electrode body is used to prevent the permeation of oxygen gas only by the exterior material. The speed is increasing. Although the heat resistance deterioration rate can be slowed by the heat resistance stabilizer such as the antioxidant, it is not the ratio of the presence or absence of the metal electrode body. For this reason, only the creeping portion of the metal electrode body undergoes heat-resistant oxidation to temporarily increase the resistance, but the portion covered with the metal electrode body normally generates heat, and this heat accelerates further deterioration of the creeping portion. Finally, there was a risk of low resistance and cracking, resulting in abnormal overheating and ignition. As described above, the conventional PTC heating element as shown in FIG. 6 has a risk of deteriorating safety due to the difference in oxidative deterioration rate.

本発明は上記問題点に鑑み、劣化しても、安全な正抵抗
温度係数発熱体を提供することを目的とする。In view of the above problems, it is an object of the present invention to provide a positive resistance temperature coefficient heating element that is safe even if it deteriorates.

問題点を解決するための手段 上記問題点を解決する本発明の技術的手段は、結晶性高
分子中に導電性微粉末を分散させた組成物を主成分とす
る薄肉正抵抗温度係数抵抗体と、その厚さ方向に電圧を
印加すべく設けられた一対の金属よりなる電極体と、前
記一対の電極体が互いに重合されない部分に設けられた
高電気絶縁体とを備え、前記高電気絶縁体は前記抵抗体
と相溶性を有する材料よりなるものである。Means for Solving the Problems The technical means of the present invention for solving the above problems is a thin positive temperature coefficient resistor having a composition in which a conductive fine powder is dispersed in a crystalline polymer as a main component. And a high electrical insulator provided in a portion where the pair of electrode bodies are not polymerized with each other, and a high electrical insulator provided so as to apply a voltage in the thickness direction thereof. The body is made of a material compatible with the resistor.

作用 この技術的手段による作用は次のようになる。Action The action of this technical means is as follows.

すなわち、従来、薄肉抵抗体の内面に一対の金属電極体
が電気的に接続するように構成されていたが、金属電極
体で覆われていない部分は覆われている部分より酸化劣
化速度が速く、このためついには、低抵抗化，亀裂発生
等の現象が生じ、異常過熱，発火等の危険性を有してい
たが、一対の金属電極体が覆われていない部分にPTC抵
抗体と相溶性を有する高電気絶縁体を設けることによ
り、この部分の電気絶縁性能を向上させるだけでなく、
PTC抵抗体、電気絶縁体との密着性を高め、PTC抵抗体へ
の空気の流入を抑えることもできる。また、PTC抵抗体
は金属電極体の覆われている酸化劣化しにくいところに
存在し、しかも均一な劣化速度であるため安全となる。That is, conventionally, a pair of metal electrode bodies was configured to be electrically connected to the inner surface of the thin-walled resistor, but the portion not covered with the metal electrode body has a higher oxidation deterioration rate than the covered portion. For this reason, finally, there was a risk of low resistance, cracking, etc., and there was a risk of abnormal overheating, ignition, etc., but the part not covered by the pair of metal electrode bodies was not covered with the PTC resistor. By providing a high electrical insulator having solubility, not only the electrical insulation performance of this portion is improved,
It is also possible to improve the adhesion to the PTC resistor and the electrical insulator and suppress the inflow of air into the PTC resistor. Further, the PTC resistor is present in the area where the metal electrode body is covered, which is resistant to oxidative deterioration, and has a uniform deterioration rate, which is safe.

実施例 以下、本発明の一実施例を添付図面に基づいて説明す
る。Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

なお、同一の部品については同一番号を付与する。第１
図において、３は厚さ0.6mmの薄肉板状のPTC抵抗体であ
り、この抵抗体３の上下面に金属板状の電極4,5が接着
されている。さらに、この沿面部分に高電気絶縁体６を
抵抗体３及び電極体4,5に密着させて構成している。The same parts are given the same numbers. First
In the figure, 3 is a thin-walled plate-shaped PTC resistor having a thickness of 0.6 mm, and metal plate-shaped electrodes 4 and 5 are bonded to the upper and lower surfaces of the resistor 3. Further, the high electrical insulator 6 is closely attached to the resistor 3 and the electrodes 4 and 5 on this creeping portion.

ここでPTC抵抗体３はカーボンブラックを中心とする粒
子状導電剤を含有させた高分子組成物であり、例えばこ
れに用いる樹脂としてはポリエチレン−酢酸ビニル共重
合体，ポリエチレン−エチルアクリレート共重合体，ポ
リエチレン，ポリプロピレン等のポリオレフィンやポリ
アミド，ポリハロゲン化ビニリデン，ポリエステル等の
結晶性樹脂があり、各々の結晶変態点付近で急激な正の
温度係数を示す。また一対の電極4,5の距離は0.3〜3mm
程度であり、PTC抵抗体３は高比抵抗の組成物でよく、
自己温度制御性のためのPTC特性は容易に得られる。Here, the PTC resistor 3 is a polymer composition containing a particulate conductive agent centered on carbon black, and examples of the resin used therefor include polyethylene-vinyl acetate copolymer and polyethylene-ethyl acrylate copolymer. Polyolefins such as polyethylene and polypropylene, and crystalline resins such as polyamides, polyvinylidene halides, and polyesters have a sharp positive temperature coefficient near their crystal transformation points. The distance between the pair of electrodes 4 and 5 is 0.3 to 3 mm.
The PTC resistor 3 may be a composition having a high specific resistance.
PTC characteristics for self-temperature controllability are easily obtained.

次に、電極4,5としては、本実施例では厚みが35μｍの
銅箔を用いたが、金属導電体であればどのようなもので
あってもよい。Next, as the electrodes 4 and 5, a copper foil having a thickness of 35 μm was used in this embodiment, but any metal conductor may be used.

高電気絶縁体６はこのPTC発熱体の使用温度域で体積固
有抵抗が10¹⁰Ωcm以上であれば、一般の高分子材料であ
り、PTC抵抗体材料と相溶性を有する材料であればよ
い。この実施例ではポリプロピレン樹脂を用いた。この
ように、一対の電極4,5が重合しない部分に高電気絶縁
体を設けることにより、接近した異極電極4,5の短絡防
止はもちろんのことPTC抵抗体３は金属電極体に覆われ
ることになり、金属の酸素ガス透過度は０のため酸化劣
化しにくく長寿命のPTC発熱体を提供するばかりでな
く、酸化劣化速度は同一であり、劣化の際も安全な発熱
体を提供するという優れた効果を奏するものである。構
成上、部分的にPTC抵抗体が金属に覆われない部分が存
在する場合は、この部分を他の金属板で絶縁体を介して
覆ったり、この部分に何らかの安全装置を設けて、劣化
の際に、発熱体の通電を停止させるようにすることもで
きる。The high electrical insulator 6 is a general polymer material as long as it has a volume resistivity of 10 ¹⁰ Ωcm or more in the operating temperature range of this PTC heating element, and may be a material compatible with the PTC resistor material. In this example, polypropylene resin was used. In this way, by providing a high electrical insulator in a portion where the pair of electrodes 4 and 5 do not polymerize, the PTC resistor 3 is covered with the metal electrode body as well as preventing short circuit between the different polarity electrodes 4 and 5 that are close to each other. In addition, since the oxygen gas permeability of the metal is zero, it not only provides a PTC heating element that is resistant to oxidative deterioration and has a long life, but also has the same oxidative deterioration rate and provides a safe heating element even when it deteriorates. That is an excellent effect. If there is a part where the PTC resistor is not covered with metal due to the configuration, this part may be covered with another metal plate via an insulator, or some kind of safety device may be provided in this part to prevent deterioration. At this time, it is also possible to stop the energization of the heating element.

次に、第２図は、本発明の第２の実施例を示すが、絶縁
体６が一対の電極4,5間にも介在させるように構成して
いる。これにより加工ばらつき等によりPTC抵抗体３
が、電極4,5の重合しない部分にはみ出したりすること
なく、劣化の際の安全性を向上させられる。また、第１
図，第２図に示す構成の加工については、押出機２機を
用いることにより容易に加工することができる。Next, FIG. 2 shows a second embodiment of the present invention, in which the insulator 6 is also interposed between the pair of electrodes 4 and 5. As a result, due to variations in processing, etc., the PTC resistor 3
However, the safety at the time of deterioration can be improved without protruding to the unpolymerized portions of the electrodes 4 and 5. Also, the first
The processing shown in FIGS. 2 and 3 can be easily processed by using two extruders.

また、高電気絶縁体６をPTC抵抗体３より融点の高い材
料にすると、PTC抵抗体が高温で軟化するような状態に
おいても、電気絶縁体６により堅実に保持されているた
め、上下方向の力が加わっても安全であるという効果も
奏する。If the high electrical insulator 6 is made of a material having a melting point higher than that of the PTC resistor 3, the high electrical insulator 6 is firmly held by the electrical insulator 6 even when the PTC resistor softens at a high temperature. It also has the effect of being safe even if force is applied.

なお、本発明の高電気絶縁体６とPTC抵抗体３とは相溶
性を有しているので、両者が十分に密着し、この間に空
気を残さないようにすることができ、接近した一対の異
極電極4,5間の耐電圧性能を向上させ、安全性をアップ
できるばかりか、この両者の密着部分より長期使用に際
し高電気絶縁体６がPTC抵抗体３に溶け込んでいき、劣
化の際の安全性をさらに向上させることができる。Since the high electrical insulator 6 of the present invention and the PTC resistor 3 are compatible with each other, they can be sufficiently adhered to each other so that air is not left between them, and a pair of close contacts are provided. Not only can the withstand voltage performance between the electrodes 4 and 5 of different polarity be improved to improve safety, but the high electrical insulator 6 will melt into the PTC resistor 3 during long-term use than the contact area between these electrodes, and when it deteriorates. The safety of can be further improved.

さらに、高電気絶縁体６を難燃材料にすることにより、
PTC抵抗体３の異物混入、電極4,5のバリ、異常使用時な
どに万一異常加熱したりスパークが発生しても周辺への
発火を防止させることができる。Furthermore, by making the high electrical insulator 6 a flame-retardant material,
It is possible to prevent ignition to the surroundings even if abnormal heating or spark occurs in the PTC resistor 3 due to foreign matter inclusion, burrs on the electrodes 4 or 5, or abnormal use.

本実施例によれば、以上に示すような優れた効果を示す
ものであり、一対の電極が重合しない部分にPTC抵抗体
と相溶性をもつ高電気絶縁体を設けた構成であれば、ど
のような構成であってもよく、第３図〜第５図に示すよ
うな構成でもよい。ここで第３図は、電極４に孔が開い
ている場合であり、この孔部にも高電気絶縁体６を配し
ている。According to the present embodiment, which exhibits the above-mentioned excellent effects, and in which the pair of electrodes is provided with a high electrical insulator having compatibility with the PTC resistor in the non-polymerizable portion, Such a configuration may be used, or the configurations shown in FIGS. 3 to 5 may be used. Here, FIG. 3 shows the case where a hole is formed in the electrode 4, and the high electrical insulator 6 is also arranged in this hole.

以上の実施例は、PTC発熱体の外装材，熱負荷体などに
ついては、言及していないが、当然外装材や熱負荷体等
が構成されたものでもよく、全てが構成された際に本発
明の構成が実現できるものであればよい。The above examples do not refer to the exterior material of the PTC heating element, the heat load body, etc., but naturally, the exterior material, the heat load body, etc. may be configured, and when all are configured, the It is sufficient that the configuration of the invention can be realized.

発明の効果 以上述べてきたように、本発明によれば、以下の効果を
奏するものである。EFFECTS OF THE INVENTION As described above, the present invention has the following effects.

（１）PTC抵抗体を金属電極で両面より覆っているの
で、この覆われている全面分において均一に、PTC抵抗
体の酸化劣化を抑制でき、長寿命化を図ることができ
る。(1) Since the PTC resistor is covered with the metal electrodes from both sides, it is possible to uniformly suppress the oxidative deterioration of the PTC resistor over the entire covered surface, and to prolong the service life.

（２）金属電極で両面より覆われていない部分は、PTC
抵抗体と相溶性のある高電気絶縁体を設けているので、
一対の電極が重合している部分と重合していない部分の
境界部分の異極電極間の耐電圧性能を向上させることが
できるばかりか、長期使用後の往生際の安全性も高める
ことができる。(2) PTC is the area not covered with metal electrodes on both sides.
Since a high electrical insulator compatible with the resistor is provided,
Not only can the withstand voltage performance between the electrodes of different polarities at the boundary portion between the portion where the pair of electrodes are superposed and the portion where they are not superposed be improved, but also the safety in the case of a long life after use can be improved.

（３）簡易な構成で高発熱量、高信頼性のPTC発熱体を
実現でき、使用上、きわめて有利なものである。(3) A PTC heating element with high heat generation and high reliability can be realized with a simple structure, which is extremely advantageous in use.

【図面の簡単な説明】[Brief description of drawings]

第１図は本発明の第１の実施例の正抵抗温度係数発熱体
の斜視図、第２図は同第２の実施例の正抵抗温度係数発
熱体の斜視図、第３図は同第３の実施例の正抵抗温度係
数発熱体の斜視図、第４図は同第４の実施例の正抵抗温
度係数発熱体の断面図、第５図は同第５の実施例の正抵
抗温度係数発熱体の断面図、第６図は従来の正抵抗温度
係数発熱体の斜視図である。 ３……PTC抵抗体、4,5……電極、６……高電気絶縁体。FIG. 1 is a perspective view of a positive resistance temperature coefficient heating element according to a first embodiment of the present invention, FIG. 2 is a perspective view of the positive resistance temperature coefficient heating element according to the second embodiment, and FIG. 3 is a perspective view of the positive resistance temperature coefficient heating element of the third embodiment, FIG. 4 is a sectional view of the positive resistance temperature coefficient heating element of the fourth embodiment, and FIG. 5 is a positive resistance temperature of the fifth embodiment. FIG. 6 is a sectional view of the coefficient heating element, and FIG. 6 is a perspective view of a conventional positive resistance temperature coefficient heating element. 3 ... PTC resistor, 4,5 ... electrode, 6 ... high electrical insulator.

Claims (3)

【特許請求の範囲】[Claims] 【請求項１】結晶性高分子中に導電性微粉末を分散させ
た組成物を主成分とする薄肉正抵抗温度係数抵抗体と、
その厚さ方向に電圧を印加すべく設けられた一対の金属
よりなる電極体と、前記一対の電極体が互いに重合され
ない部分に設けられた高電気絶縁体とを備え、前記高電
気絶縁体は前記抵抗体と相溶性を有する材料よりなる正
抵抗温度係数発熱体。1. A thin-walled positive temperature coefficient resistor having a composition in which a conductive fine powder is dispersed in a crystalline polymer as a main component,
An electrode body made of a pair of metals provided to apply a voltage in the thickness direction thereof, and a high electrical insulator provided in a portion where the pair of electrode bodies are not polymerized with each other, the high electrical insulator is A positive resistance temperature coefficient heating element made of a material compatible with the resistor. 【請求項２】高電気絶縁体が、隣接した一対の電極体が
互いに重合された部分にまで介在された特許請求の範囲
第１項記載の正抵抗温度係数発熱体。2. The positive resistance temperature coefficient heating element according to claim 1, wherein the high electrical insulator is interposed even in a portion where a pair of adjacent electrode bodies are superposed on each other. 【請求項３】高電気絶縁体は抵抗体より融点の高い材料
よりなる特許請求の範囲第１項または第２項記載の正抵
抗温度係数発熱体。3. The positive resistance temperature coefficient heating element according to claim 1 or 2, wherein the high electrical insulator is made of a material having a higher melting point than that of the resistor.