【発明の詳細な説明】
（産業上の利用分野）
本発明は、樹脂発熱体に関し、更に詳しくは安
全性、発熱均一性、放熱性、通気性、通水性、断
熱性等、樹脂発熱体として優れた性能を有する新
規な構造を有する樹脂発熱体に関する。
（従来の技術）
従来、導電性カーボンや金属粉末等の導電剤を
種々の熱可塑性樹脂中に練り込んで所望の形状に
成形した樹脂発熱体は公知であり、床暖房、足温
器、保温パネル等の如き種々の加熱用具の加熱部
材として広く使用されている。
（発明が解決しようとしている問題点）
上記の如き樹脂発熱体は、熱可塑性樹脂中に高
濃度に導電性カーボンブラツク等の導電剤を練り
込んで成形し、電流を流してその抵抗により発熱
させるものであるため、練り込む導電剤は相互に
接触し、且つ均一に分散していることが必要とさ
れる。
しかしながら、熱可塑性樹脂中に多量の導電剤
を均一に分散させるのは極めて困難であり、その
結果として、成形体の物理的強度は著しく低下
し、且つ使用時には局部的な発熱や発熱不良によ
る温度むらが生じたり、特に大面積のパネル状樹
脂発熱体の場合には局部的な放熱不良から、局部
的な過熱が生じ、安全性の点で大きな問題があ
る。
又、使用中は常に周囲温度より高い温度である
ため、樹脂発熱体自体、特に表面の熱劣化や酸化
劣化が激しく、長時間使用後には上記の如き問題
は益々著しくなるものである。
物理的強度の低下の問題については、ガラスフ
アイバー等の補強材を同時に混入することも考え
られているが、これらの方法では製造が一層困難
になり、又、品質管理が一層厳しくなるにも係わ
らず、上記の問題は殆ど解決されていない。
本発明者は上記の如き従来技術の問題点を解決
すべく鋭意研究の結果、従来の棒状の複数の樹脂
発熱体を並列し、その周囲を絶縁性樹脂、特に熱
硬化性エポキシ樹脂で包囲することによつて、上
記の従来技術の問題点が十分に解決されることを
知見して本発明を完成した。
（問題点を解決するための手段）
すなわち、本発明は、熱可塑性樹脂又は熱硬化
性樹脂中に導電剤を含有させてなる複数の棒状の
導電性樹脂成形体を並列させ、その周囲に熱硬化
性エポキシ樹脂を充填して硬化させて一体化さ
せ、該一体化物の少なくとも一方の面を放熱性に
し且つ残りの少なくとも一方の面を断熱性とした
ことを特徴とする樹脂発熱体である。
次に本発明を本発明の好ましい実施例を例示す
る添付図面を参照して更に詳細に説明する。
第１図は、本発明の樹脂発熱体の１例の１部の
断面図を示すものであり、第２図は他の例の製造
時の断面図を示し、第３図は他の例の断面図を示
すものである。
まず第１図を参照すると、本発明の樹脂発熱体
１０は、基本的には複数本の棒状の導電性樹脂成
形体１と、該成形体１の周囲を包囲している熱硬
化性エポキシ樹脂層２とから構成されている。
導電性樹脂成形体１それ自体は従来公知のもの
でよく、例えば、ポリエチレン、ポリプロピレ
ン、ポリサルホン、ポリエステル、ポリカーボネ
ート、フツ素系樹脂等の如き熱可塑性樹脂中に導
電剤、例えば、導電性カーボンブラツクや金属粉
末等を高濃度に練り込んで成形したものであり、
その形状は線状、柱状等を含む棒状体であり、そ
のサイズ及び長さは特に限定されない。このよう
な導電性樹脂成形体１はいずれも従来公知の技術
によつて容易に製造することが可能である。
このような導電性樹脂成形体１を包囲する熱硬
化性エポキシ樹脂層２は電気的に絶縁性であれば
よい。
このような本発明の樹脂発熱体１０において
は、導電性樹脂成形体１の表面に絶縁性の保護被
膜３を形成して安全性を更に高めることができ
る。又、成形体１を包囲している熱硬化性エポキ
シ樹脂２の放熱面４となる面には、熱伝導性の良
好な充填剤（例えば、無機充填剤や金属粉）を充
填してその放熱性を高め、一方、断熱面５となる
べき部分には断熱効果の良い充填剤（例えば、シ
ラスバルーン、中空パイプ等）を混入又は配置す
ることが好ましい。
次に第２図を参照すると、第２図は本発明の樹
脂発熱体１０の製造方法をも示すものであり、図
中の６は成形用の型枠であり、該型枠中に複数の
導電性樹脂成形体１を配置し、型枠６と成形体１
との間隙中に、熱硬化性エポキシ樹脂２を注入
し、これを硬化させることによつて本発明の樹脂
発熱体１０が得られる。このような方法におい
て、形成される熱硬化性エポキシ樹脂層２は全体
的に均一層としてもよいが、得られる樹脂発熱体
１０の用途に応じて少なくとも一方の面５を断熱
性とし、他の面４を放熱性とするのが好ましい。
一方の面を断熱性にするためには、例えば、型枠
中に熱硬化性エポキシ樹脂２を注入するに際し
て、まず最初に断熱性充填剤を包含させたものを
注入して断熱層５を形成し、次いで熱伝導性の良
好な充填剤を混入させた熱硬化性エポキシ樹脂２
を注入させて放熱面４を形成する方法、第３図に
示す如く断熱面中に中空パイプ７等を埋設する方
法等いずれの方法でもよい。
又、第２図に示す如く平板状の樹脂発熱体１０
を得る場合には、その平板中の導電性樹脂成形体
１の存在しない部分に孔８を設けて通気性や通水
性等を有する形状の樹脂発熱体１０とすることも
できる。
（作用・効果）
以上の如き本発明によれば、従来の導電性樹脂
を棒状の成形体とし、該成形体を熱硬化性エポキ
シ樹脂中に埋設して硬化させて所望の形状とする
ことによつて、従来技術における種々の問題点、
例えば、強度の不足、成形体の熱劣化等の問題が
解決される。又、導電性樹脂成形体を多数の線状
体や棒状体とすることにより、発熱昇温のコント
ロールが自由にでき、異常発熱や発熱不良、放熱
の不均一性等の種々の問題も解決された。又、得
られる樹脂発熱体の任意の面を断熱面としたり放
熱面とすることも可能であるため、種々の用途に
適応することができる。又、得られる樹脂発熱体
中に任意の安全な通気孔や通水孔を設けることが
できるので、樹脂発熱体の用途を著しく拡大する
ことができる。
従つて、本発明の樹脂発熱体は、結露防止器、
布団乾燥機、床暖房、足温器、椅子暖房、机暖
房、神経痛リウマチス治療、車電池保温、育苗保
温、人工保育器、家畜保温、融雪パネル、風呂
床、保温パネル、風呂槽保温、コンクリート養生
保温、冷凍庫扉凍結防止、水道凍結防止、複写機
予熱、鉄道ポイントレール保温、熱帯魚水槽保
温、ウオーターベツト保温、熱排気ダクト対流排
出器、洗面台、温湯設備等の用途に有用である。
（実施例）
熱可塑性樹脂中に導電性カーボンを39phrの割
合で練り込み、直径4.5mmの棒状に成形した。該
成形体を800mmの長さに切断し、その両端部に電
源接続端子をとり付けた、成型用型枠として深さ
20mm、縦90cm、横90cmの平皿状型枠を作成し、そ
の底に外型５mm、内型４mmの合成樹脂パイプを20
mmの間隔をおいて並べた。並べた合成樹脂パイプ
と直角方向に上記の成形体10本を40mmの間隔にお
いて固定し、型枠中の空隙中に無機充填剤を
30phrの割合で含有する熱硬化性エポキシ樹脂を
注入し成形体を埋没させた。次に型枠全体を約40
乃至60℃に２乃至３時間加熱させて全体を硬化さ
せて本発明の樹脂発熱体を得た。
この成形体の端部に設けた電源接続部に100V
の電源を接続した。室温16℃、湿度60％の雰囲気
下で時間の経過、消費電流及び発熱温度を測定し
たところ次の結果を得た。
【表】
又、上記の本発明の樹脂発熱体に対し、印加す
る電圧を変化させ、一定時間経過後の樹脂発熱体
の10ケ所の温度を測定したところ、下記の通り一
定の発熱を示し、異常発熱は見られなかつた。
基準測定雰囲気温度＝20℃
【表】
比較例
実施例で使用したと同様な導電性樹脂を使用
し、この導電性樹脂から実施例の発熱体と同一寸
法の発熱パネルを作成し、実施例と同様に両端に
接続端子を設け、印加する電圧を変化させ、一定
時間経過後の樹脂発熱体の10ケ所の温度を測定し
たところ、下記の通り70℃前後においては発熱体
の各部分において著しい温度差が発生し、極端な
場合には50℃もの温度差が認められた。
【表】 Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a resin heating element, and more specifically, the present invention relates to a resin heating element, and more specifically, the invention relates to a resin heating element that has various properties such as safety, uniformity of heat generation, heat dissipation, air permeability, water permeability, heat insulation, etc. The present invention relates to a resin heating element having a novel structure with excellent performance. (Prior Art) Conventionally, resin heating elements made by kneading conductive agents such as conductive carbon or metal powder into various thermoplastic resins and molding them into desired shapes have been known, and are used in floor heating, foot warmers, and heat insulation. It is widely used as a heating member for various heating tools such as panels. (Problems to be Solved by the Invention) The above-mentioned resin heating element is made by kneading a conductive agent such as conductive carbon black at a high concentration into a thermoplastic resin, molding it, and then passing an electric current through it to generate heat due to the resistance. Therefore, the conductive agents mixed in must be in contact with each other and uniformly dispersed. However, it is extremely difficult to uniformly disperse a large amount of conductive agent in a thermoplastic resin, and as a result, the physical strength of the molded product is significantly reduced, and during use, the temperature rises due to local heat generation or heat generation failure. In the case of a panel-shaped resin heating element having a large area, uneven heating may occur, and local overheating may occur due to localized heat dissipation defects, which poses a serious problem in terms of safety. Furthermore, since the temperature is always higher than the ambient temperature during use, the resin heating element itself, especially its surface, undergoes severe thermal deterioration and oxidative deterioration, and the above-mentioned problems become even more serious after long-term use. Regarding the problem of decrease in physical strength, it is considered that reinforcing materials such as glass fibers are mixed in at the same time, but these methods make manufacturing more difficult and quality control becomes more stringent. However, most of the above problems remain unsolved. As a result of intensive research in order to solve the problems of the prior art as described above, the inventor of the present invention arranged a plurality of conventional rod-shaped resin heating elements in parallel and surrounded them with an insulating resin, particularly a thermosetting epoxy resin. In particular, the present invention was completed based on the finding that the above-mentioned problems of the prior art can be satisfactorily solved. (Means for Solving the Problems) That is, the present invention arranges a plurality of rod-shaped conductive resin molded bodies made of thermoplastic resin or thermosetting resin containing a conductive agent in parallel, and heats the surroundings of the rod-shaped conductive resin molded bodies. This resin heating element is characterized in that it is filled with a curable epoxy resin, cured and integrated, and has at least one surface of the integrated product having heat dissipating properties and at least one remaining surface having heat insulating properties. The invention will now be described in more detail with reference to the accompanying drawings, which illustrate preferred embodiments of the invention. FIG. 1 shows a cross-sectional view of a part of one example of the resin heating element of the present invention, FIG. 2 shows a cross-sectional view of another example during manufacture, and FIG. 3 shows a cross-sectional view of another example. It shows a cross-sectional view. First, referring to FIG. 1, the resin heating element 10 of the present invention basically consists of a plurality of rod-shaped conductive resin molded bodies 1 and a thermosetting epoxy resin surrounding the molded bodies 1. It is composed of layer 2. The conductive resin molded body 1 itself may be of a conventionally known type, for example, a thermoplastic resin such as polyethylene, polypropylene, polysulfone, polyester, polycarbonate, fluororesin, etc., containing a conductive agent, such as conductive carbon black or the like. It is molded by kneading metal powder etc. in high concentration,
Its shape is a rod-like body including a linear shape, a columnar shape, etc., and its size and length are not particularly limited. Any of these conductive resin molded bodies 1 can be easily manufactured using conventionally known techniques. The thermosetting epoxy resin layer 2 surrounding such a conductive resin molded body 1 may be electrically insulating. In such a resin heating element 10 of the present invention, safety can be further enhanced by forming an insulating protective coating 3 on the surface of the conductive resin molded body 1. In addition, the heat dissipation surface 4 of the thermosetting epoxy resin 2 surrounding the molded body 1 is filled with a filler having good thermal conductivity (for example, an inorganic filler or metal powder) to dissipate the heat. On the other hand, it is preferable to mix or arrange a filler with a good heat insulating effect (for example, a white glass balloon, a hollow pipe, etc.) in the portion that is to become the heat insulating surface 5. Next, referring to FIG. 2, FIG. 2 also shows a method of manufacturing the resin heating element 10 of the present invention, and 6 in the figure is a mold for molding, in which a plurality of The conductive resin molded body 1 is arranged, and the formwork 6 and the molded body 1 are placed together.
The resin heating element 10 of the present invention is obtained by injecting the thermosetting epoxy resin 2 into the gap and curing it. In such a method, the thermosetting epoxy resin layer 2 formed may be a uniform layer as a whole, but depending on the use of the resulting resin heating element 10, at least one surface 5 may be made heat insulating, and the other surface may be made heat insulating. It is preferable that the surface 4 has heat dissipation properties.
In order to make one side heat insulating, for example, when injecting the thermosetting epoxy resin 2 into the mold, first inject a material containing a heat insulating filler to form the heat insulating layer 5. and then thermosetting epoxy resin 2 mixed with a filler with good thermal conductivity.
Any method may be used, such as a method in which the heat dissipating surface 4 is formed by injecting heat radiating surface 4, or a method in which a hollow pipe 7 or the like is buried in the heat insulating surface as shown in FIG. Further, as shown in FIG. 2, a flat resin heating element 10 is used.
In this case, holes 8 may be provided in the portion of the flat plate where the conductive resin molded body 1 is not present to form a resin heating element 10 having air permeability, water permeability, etc. (Operations and Effects) According to the present invention as described above, a conventional conductive resin is formed into a rod-shaped molded body, and the molded body is embedded in a thermosetting epoxy resin and cured to form a desired shape. Therefore, various problems in the conventional technology,
For example, problems such as insufficient strength and thermal deterioration of the molded body are solved. In addition, by forming the conductive resin molded body into a large number of linear or rod-shaped bodies, it is possible to freely control the heat generation temperature, and various problems such as abnormal heat generation, heat generation failure, and uneven heat radiation can be solved. Ta. Moreover, since any surface of the obtained resin heating element can be used as a heat insulating surface or a heat radiating surface, it can be applied to various uses. Further, since arbitrary safe ventilation holes and water holes can be provided in the resulting resin heating element, the uses of the resin heating element can be significantly expanded. Therefore, the resin heating element of the present invention can be used as a dew condensation preventer,
Futon dryers, floor heating, foot warmers, chair heating, desk heating, neuralgia rheumatism treatment, car battery insulation, seedling insulation, artificial incubators, livestock insulation, snow melting panels, bath floors, thermal panels, bath tank insulation, concrete curing It is useful for heat insulation, freezing prevention of freezer doors, prevention of freezing of water supplies, copy machine preheating, railway point rail insulation, tropical fish tank insulation, water bed insulation, heat exhaust duct convection dischargers, wash basins, hot water equipment, etc. (Example) Conductive carbon was kneaded into a thermoplastic resin at a ratio of 39 phr and molded into a rod shape with a diameter of 4.5 mm. The molded body was cut into a length of 800 mm, and power connection terminals were attached to both ends.
Create a plate-shaped formwork of 20 mm, length 90 cm, and width 90 cm, and attach 20 synthetic resin pipes with an outer mold of 5 mm and an inner mold of 4 mm to the bottom of it.
Arranged at mm intervals. The 10 molded bodies described above were fixed at 40 mm intervals in a direction perpendicular to the lined up synthetic resin pipes, and an inorganic filler was poured into the voids in the formwork.
A thermosetting epoxy resin containing 30 phr was injected to embed the molded body. Next, the entire formwork is approximately 40
The resin heating element of the present invention was obtained by heating at 60° C. for 2 to 3 hours to harden the entire body. 100V to the power connection provided at the end of this molded body.
The power supply was connected. The elapsed time, current consumption, and temperature of heat generation were measured under an atmosphere with a room temperature of 16°C and a humidity of 60%, and the following results were obtained. [Table] In addition, when the voltage applied to the resin heating element of the present invention was varied and the temperature was measured at 10 points after a certain period of time had elapsed, a certain level of heat generation was observed as shown below. No abnormal fever was observed. Standard measurement ambient temperature = 20℃ [Table] Comparative example Using the same conductive resin as that used in the example, a heating panel with the same dimensions as the heating element of the example was made from this conductive resin, and Similarly, connecting terminals were installed at both ends, the applied voltage was varied, and the temperature at 10 points on the resin heating element was measured after a certain period of time. Differences occurred, with temperature differences of as much as 50°C observed in extreme cases. 【table】
【図面の簡単な説明】[Brief explanation of the drawing]
第１図乃至第３図は本発明の樹脂発熱体の断面
を図解的に示す図である。
１；導電性樹脂成形体、２；熱硬化性エポキシ
樹脂、３；保護被膜、４；放熱面、５；断熱面、
６；型枠、７；中空パイプ、８；通気孔、１０；
樹脂発熱体。
FIGS. 1 to 3 are diagrams schematically showing cross sections of the resin heating element of the present invention. 1; conductive resin molded body, 2; thermosetting epoxy resin, 3; protective coating, 4; heat dissipation surface, 5; heat insulation surface,
6; formwork, 7; hollow pipe, 8; ventilation hole, 10 ;
Resin heating element.