JPH0311581A - Temperature self-controlling heat generator - Google Patents

Abstract

PURPOSE:To realize a uniform potential distribution between electrode lines by attaching closely high heat-conductive plates to both sides of a temperature self-controlling heat generator which is made by arranging a pair of parallel electrode lines in a composition made by mixing and kneading carbon black and a crystalline resin. CONSTITUTION:A composition 3 made by mixing and kneading a crytalline resin 1 and carbon black 2 is extruded and formed around a pair of electrode lines such as copper wires arranged parallel. Then, on both sides of the formation 3, high conductive plates 5 such as a copper foil are heat-fused while applying a pressure. Furthermore, electron beams are radiated, and a temperature self-controlling heat generator 6 is obtained. This temperature self-controlling heat generator 6 diffuses immediately the heat generated by a voltage concentration between the electrodes lines 4, with the high conductive plates 5, and the generation of an unevenness of heating temperature can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a self-temperature-controlled heating element having a positive temperature coefficient of resistance (hereinafter referred to as PTC characteristic) used for floor heating, antifreeze, etc.

2. Description of the Related Art A conventional self-temperature control heating element of this type consists of a pair of parallel electrode wires 7 and a material made of low-density polyethylene or the like disposed between and in close contact with the electrodes 7, as shown in FIG. Kneaded composition 1 obtained by kneading crystalline resin 8 and carbon black 9
0, and was formed by radiation crosslinking.

Problems to be Solved by the Invention However, with such a structure, by supplying electricity (particularly in an atmosphere of high temperature, e.g. 100°C)
In the case of 00V current supply, there was a problem in that the heat generation temperature decreased after 100 hours.

Observation of the heat generation temperature distribution in the cross section of the heating element (thermo viewer) revealed that the cause was uneven heat generation temperature.

That is, a conductive path between the carbon black 9 and the crystalline resin 8, which is created by uniformly dispersing the carbon black 9 in the crystalline resin 8, causes the temperature to increase due to local voltage concentration, and therefore the crystalline resin 8 It was thought that the carbon blank 9 was broken due to partial aggregation (decreased dispersibility) of the carbon blank 9 as it softened. Incidentally, this heating temperature unevenness becomes more pronounced as the distance between the electrode wires 7 increases, and therefore the size of the heating element is limited.

The present invention has been made to solve these conventional problems, and aims to provide a highly reliable and versatile self-temperature-controlled heating element.

Means for Solving the Problems In order to solve the above problems, the self-temperature control heating element of the present invention includes a kneaded composition of carbon blank and crystalline resin,
It consists of a pair of parallel, good thermally conductive flat plates that are provided in close contact with the composition with the composition interposed therebetween, and a pair of parallel electrode wires that are located between the flat plates and arranged in a direction perpendicular to the flat plates. .

Function The self-temperature-controlled heating element according to the present invention has the function of immediately diffusing the heat generated by the voltage concentration between the electrode wires through the flat plate with good thermal conductivity, thereby preventing the occurrence of heat generation temperature unevenness.

EXAMPLE Hereinafter, one example of the self-temperature-controlling heating element of the present invention will be described with reference to FIG.

As the crystalline resin 1, for example, Atomer HB310 (manufactured by Mitsui Petrochemical Corporation, melting point 130°C) is added, and as the carbon black 2, for example, Diablack G (Ryo Kasei Corporation, particle size 80 mμ, PH 8.0) is added in a predetermined amount. Kneaded composition 3 obtained by kneading 20 times was applied to a pair of copper wires.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a self-temperature-controlled heating element according to an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional self-temperature-controlled heating element. DESCRIPTION OF SYMBOLS 1...Crystalline resin, 2...Carbon black, 3...Kneading composition, 4...Electrode wire, 5-...Good thermal conductivity Gender plate.

Claims (1)

[Claims] A kneaded composition of carbon black and a crystalline resin, a pair of parallel good thermally conductive flat plates provided in close contact with the composition with the composition interposed therebetween, and placed between the flat plates in a direction perpendicular thereto. A self-temperature-controlled heating element consisting of a pair of parallel electrode wires.