JP2012227034A - Planar heating element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin planar heating element, having a high PTC characteristic and high reliability.SOLUTION: A planar heating element comprises: an unwoven fabric 6; a PTC resistor 5 which is stuck with the unwoven fabric 6 like a thin film by calendar processing; a pair of plates 8 which are electrically connected with the PTC resistor 5 at an interval from 20 mm to 250 mm; two polyester films 2 and 3 which cover the unwoven fabric 6, the PTC resistor 5, and the plates 8 from both sides using hot-melt adhesive 4; and a heat conductive member 11 which is bonded in at least one of external surfaces of the polyester films 2 and 3.

Description

  The present invention relates to a planar heating element that is thin and environmentally friendly and has PTC characteristics suitable for EV heating and lithium ion battery heating.

  Conventionally, for this type of planar heating element, a base polymer and a conductive material such as carbon black, metal powder, and graphite are dispersed in a solvent to form a resistor ink, which is then printed and dried on a substrate for energization. The resistor composition that generates heat is used. In particular, many have a PTC characteristic using a crystalline resin as a base polymer (see, for example, Patent Documents 1, 2, and 3).

  FIG. 4 is a plan view (a) and a cross-sectional view (b) taken along line xy of a conventional sheet heating element having PTC characteristics. As shown in FIG. 4, the planar heating element includes a pair of comb-shaped electrodes 51 obtained by printing and drying a conductive paste such as a silver paste on an electrically insulating base material 50 such as a polyester film. 52 and a polymer resistor 53 obtained by printing and drying a polymer resistor ink at a position to which power is supplied, and comb-shaped electrodes 51 and 52 with a covering material 54 similar to that of the substrate 50. The polymer resistor 53 is covered and protected.

  When a polyester film is used as the base material 50 and the covering material 54, for example, a modified polyethylene-based heat-fusible resin 55 is bonded to the covering material 54 in advance, and the pressure is applied while applying heat (pressure during heating). Thus, the base material 50 and the covering material 54 are joined via the heat-fusible resin 55. Thereby, the comb-shaped electrodes 51 and 52 and the polymer resistor 53 are isolated from the outside world, and long-term reliability is imparted.

  The PTC characteristic is a resistance temperature characteristic in which the resistance value increases as the temperature rises, and when the temperature reaches a certain temperature, the resistance value rapidly increases (takes the initial letter of English Positive Temperature Coefficient, which means that the resistance has a positive temperature coefficient) The polymer resistor 53 having PTC characteristics can provide a planar heating element having a self-temperature adjusting function.

  In addition, the resistor composition was not formed as an ink, but was formed by extruding a kneaded material prepared by kneading a crystalline resin as a base polymer and a conductive material such as carbon black or graphite together with an electrode cable. There are also things. It is used as a freezing prevention heater. FIG. 5 shows a cross-sectional view of a conventional cable heating element.

  While the electrode cable 55 is pulled out from the die of the extruder in parallel, the resistor kneaded material 56 is extruded and coated around the electrode cable 55 and then the insulating coating material 57 is coated around the resistor kneaded material 56.

Japanese Patent Laid-Open No. 56-13689 JP-A-6-96843 JP-A-8-120182

However, in the conventional configuration, the specific resistance of the resistor composition used is usually 1000.
For example, when it is used for a DC-driven heating element for automobiles, power is supplied in close proximity like a comb-shaped electrode having an interval of several millimeters. Usually, the comb-shaped electrode is expensive because it is formed on a silver paste by printing and drying.

  On the other hand, the exothermic heating element has a thickness in millimeters compared to that used for ink, and the electrode cables are close to each other and cannot be said to be a planar heating element.

  SUMMARY OF THE INVENTION In view of the above-described problems of the conventional technology, the problem to be solved by the present invention is to provide a sheet heating element having a thin PTC characteristic having a low specific resistance and high reliability.

  In order to solve the above problems, a planar heating element of the present invention includes a non-woven fabric, a PTC resistor bonded to the non-woven fabric by calendering, and an electrical connection with the PTC resistor at an interval of 20 mm to 250 mm. A pair of electrodes connected to each other, two polyester films covering the nonwoven fabric, the PTC resistor, and the electrodes from both sides via a hot melt adhesive, and adhered to at least one surface outside the polyester film. It consists of a heat conductive member.

  With the above configuration, the PTC resistor can be made into a thin film by calendering, and the space between the electrodes can be widened. Therefore, it is possible to reduce the amount of electrode use without using a solvent like ink, that is, environmentally thin and thin. A planar heating element capable of realizing cost reduction can be provided.

The top view and sectional view showing the sheet heating element in the embodiment of the present invention Schematic showing the calendar processing of the present invention Schematic showing the laminating process of the present invention Plan view showing a conventional planar heating element Sectional view of a conventional cable-shaped heating element

  The planar heating element of the present invention includes a non-woven fabric, a PTC resistor bonded to the non-woven fabric by calendering, and a pair of electrodes electrically connected to the PTC resistor at intervals of 20 mm to 250 mm. , Two polyester films that coat the nonwoven fabric, the PTC resistor, and the electrode from both sides with a hot melt adhesive, and a heat conductive member that is bonded to at least one outer surface of the polyester film.

  With this configuration, the PTC resistor can be made into a thin film by calendering, and the space between the electrodes can be widened. Therefore, it is possible to reduce the amount of electrode use without using a solvent like ink, that is, it is environmentally thin and thin. A planar heating element capable of realizing cost reduction can be provided.

  Moreover, the planar heating element of this invention uses the nonwoven fabric made from a mesh polyester which has an opening part as a nonwoven fabric.

With this configuration, since the mesh-like nonwoven fabric has openings and the fibers are only entangled (hydroentanglement), the thermal shrinkage at the melting temperature of the PTC resistor during calendar processing can be absorbed by the fiber displacement. Therefore, since the PTC resistor can be provided as a finished calendar product, it is possible to provide a planar heating element that can be easily post-processed such as lamination using a polyester film with a hot melt adhesive.

  The planar heating element of the present invention comprises a resin composition comprising a low melting crystalline resin having a melting point of at least 100 ° C. and a high melting crystalline resin having a melting point of 100 ° C. or higher, and at least two types of carbon. A PTC resistor is composed of a conductor made of black, a release agent, a dispersion stabilizer, and a reactive additive.

  With this configuration, the low melting crystalline resin exhibits PTC characteristics, the high melting crystalline resin has heat resistance, the PTC characteristics with two types of carbon black, and the mold release during calendaring with a mold release agent and a dispersion stabilizer. And the PTC resistor kneaded mass can be bonded with resin and carbon black with a reactive additive, PTC characteristics can be easily set, and resistance stability suitable for calendering is high. A planar heating element can be provided.

  In the planar heating element of the present invention, the resin composition is composed of a low-melting crystalline resin, a high-melting crystalline resin, and a maleic anhydride-modified crystalline resin.

  With this structure, the maleic anhydride modified crystalline resin binds between the low-melting crystalline resin and the high-melting crystalline resin, and bonds the low-melting and high-melting crystalline resin and the conductor made of carbon black. Thus, a planar heating element with high resistance value stability can be provided.

  The planar heating element of the present invention comprises a resin composition comprising 0 to 60% low-melting crystalline resin, 30 to 85% high-melting crystalline resin, and 15 to 40% maleic anhydride-modified crystals. The resin component is composed of a functional resin.

  With this configuration, a planar heating element is provided that can adjust the temperature at which the PTC characteristics of the low-melting crystalline resin are expressed, the degree of heat resistance imparted by the high-melting crystalline resin, and the resistance stability of the maleic anhydride-modified crystalline resin. it can.

  The planar heating element of the present invention uses as a conductor a combination of carbon black A having a primary particle diameter of 10 to 30 nanometers, carbon black B having a primary particle diameter of 60 to 150 nanometers, and graphite. It becomes.

  With this configuration, it is possible to obtain a conductor that can exhibit resistance stability and conductivity with carbon black A, PTC characteristics with carbon black B, and conductivity, PTC characteristics, and thermal conductivity with graphite.

  In addition, the planar heating element of the present invention is made by using exfoliated graphite or spheroidized graphite alone or in combination as graphite.

  With this configuration, the PTC characteristic can be adjusted not only by carbon black but also by graphite, and a planar heating element having a wide adjustment range of the PTC characteristic can be provided.

  Further, the planar heating element of the present invention uses a reactive silicone oil as a release agent, acrylic modified polytetrafluoroethylene as a dispersion stabilizer, and a coupling agent as a reactive additive.

With this configuration, the reactive silicone oil can impart roll releasability during calendering and can exhibit affinity with the PTC resistor kneaded material. In addition, the acrylic modified polytetrafluoroethylene can stretch the acrylic portion in a spider web in the PTC resistor to exhibit a unity of the PTC resistor kneaded material, thereby improving the calendering suitability. Furthermore, a chemical bonding is generated between the conductor and the crystalline resin by the coupling agent, and a planar heating element with high resistance stability can be provided.

  The planar heating element of the present invention uses a tin-plated copper aggregate stranded wire as an electrode, a tin-plated copper aggregate stranded wire coated with a coating resistor, or a crystalline polyester resin as a hot melt adhesive.

  With this configuration, if a tin-plated copper aggregate strand can be used alone as an electrode, a low-cost electrode can be provided. Moreover, when it is difficult to use alone, the PTC resistor and the tin-plated copper aggregate strand can be electrically connected with the covering resistor as an intermediate.

  Further, the planar heating element of the present invention includes a high melting crystalline resin having a melting point of at least 100 ° C., a conductor composed of carbon black, conductive fibers, and carbon nanotubes, a dispersion stabilizer, and a reactive additive. A coating resistor is formed from the agent.

  This configuration balances the high cost / high conductivity of carbon nanotubes, the flame retardancy / spark generation prevention / low conductivity of conductive fibers, and the low cost / medium conductivity of carbon black, eliminating the need for PTC characteristics. A multi-coated resistor can be provided.

  The planar heating element of the present invention uses a pre-heated conductor and a reactive additive as a covering resistor.

  With this configuration, the conductor and the reactive additive are pre-heated in advance, so that the reaction of the reactive additive can be terminated, so that the covering resistor is extruded around the tin-plated copper aggregate strands. At this time, bubbles generated during the reaction can be eliminated, and a coated resistor having a clean surface can be produced.

  In addition, the planar heating element of the present invention is formed using one or both of an aluminum film and a plate material as a heat conductive member.

  With this configuration, the temperature distribution of the PTC resistor can be made uniform, and a planar heating element excellent in durability without generating a heat spot can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the present embodiment.

(Embodiment 1)
1A and 1B are a plan view and a cross-sectional view showing a planar heating element according to Embodiment 1 of the present invention. In the cross-sectional view (b), the laminated state is shown for easy understanding. Actually, all of these are heat-sealed and integrated.

  In FIG. 1, a planar heating element 1 includes two polyester films, for example, a thick polyester film A2 having a thickness of 188 μm and a thin polyester film B having a thickness of 50 μm, both of which are crystallized as a hot melt adhesive 4 by a T-die extrusion method. The polyester resin (trade name “Byron GM920”, melting point 110 ° C., manufactured by Toyobo Co., Ltd.) is provided in a thickness of 55 micrometers.

The PTC resistor 5 is bonded to the meshed polyester nonwoven fabric 6 with a thickness of about 100 μm in a thin film by calendering. The PTC resistor 5 of the PTC resistor calendar product 7 and the covering resistor as the electrode 8 9, the tin-plated copper aggregate strand 10 covered by extrusion is electrically connected. Specifically, a pair of electrodes 8 are arranged at a distance of about 40 mm between the polyester film A2 with hot melt adhesive and the polyester film B3 with hot melt adhesive by laminating, and the electrode 8 and the PTC resistor 5 are disposed. This is realized by laminating in the state of being close to each other. The rubber roll temperature of the laminating machine is set between 180 ° C. and 200 ° C. At this temperature, the hot melt adhesive 4, the PTC resistor 5, and the covering resistor 9 are melted, and the tin-plated copper aggregate strand 10 The covering resistor 9 and the PTC resistor 5 are heat-sealed, and the periphery thereof is covered with polyester films 2 and 3 with a hot-melt adhesive. Reference numeral 11 denotes an aluminum plate as a heat conductive member, which is bonded to the polyester film A with an adhesive.

  FIG. 2 shows a state of calendar processing. Six calendar rolls 12 set at 150 ° C. are provided, and the melted PTC resistor 5 is inserted between the calender rolls 12A and B at the top of the head. The melting process is performed by a hot roll or an extruder.

  The charged PTC resistor 5 passes through the calendar rolls 12B, C, D, and E, and the film thickness is gradually reduced between them. The final PTC resistor 5 is adjusted to reach the final calendar roll 12F and have a thickness of about 100 μm. In this stable state, the thin film of the PTC resistor 5 is transferred from the calender roll 12 to the mesh-like polyester nonwoven fabric 6 by pressing the mesh-like polyester nonwoven fabric 6 from below with the touch roll 13 against the calendar roll 12F. A thin film of the PTC resistor 5 is formed so as to partially bite into the mesh-like polyester nonwoven fabric 6. The calendar product 14 of the PTC resistor 5 is produced in such a form that it is cooled and wound at a constant speed.

  FIG. 3 shows a state of laminating. 15 is a laminate roll of silicon rubber coating, which is set at about 180 ° C. The polyester film A2 with hot melt adhesive is provided below the laminating roll 15 and the polyester film B3 with hot melt adhesive is provided on the laminating roll 15 and drawn into the laminating roll 15 from there. The contact surface with the laminating roll 15 is a polyester film, and the opposite surface is a hot melt adhesive.

  The electrodes 8 are inserted at regular intervals between the polyester films A2 and B3 with hot melt adhesive, and the calendar product 14 is inserted so that the PTC resistor 5 is in contact with the electrodes 8 between the electrodes 8 and the polyester film A2. In this state, it is introduced between the two laminate rolls 15. And the state in which the PTC resistor 5 and the electrode 8 are sealed between the polyester films A2 and B3 via the hot melt adhesive with the linear pressure of the laminate roll 15, that is, the laminate 16 can be obtained. The laminating temperature is related to the laminating speed. When the laminating speed increases, the laminating roll temperature needs to be set higher. Also, in order to melt the hot melt adhesive in advance, as shown in the polyester film B3 with hot melt adhesive in FIG. 3, it is introduced into the linear pressure portion of the laminate roll in a melted state along the laminate roll. Thus, it is possible to obtain the laminated product 16 and the planar heating element 1 with stable quality.

  This laminate product is subjected to a high temperature heat treatment and a cooling / heating cycle treatment, terminal treatment, and an aluminum plate of t = 0.5 mm is bonded with an adhesive to form a sheet heating element.

As the crystalline resin, the PTC resistor 5 is composed of 10% by weight of ethylene / methyl methacrylate copolymer (trade name “ACRIFTH WH206”, melting point 86 ° C., manufactured by Sumitomo Chemical Co., Ltd.), low-density polyethylene (product) Name “Petrocene 208”, melting point 111 ° C., manufactured by Tosoh Corporation) 15% by weight, maleic anhydride modified linear low density polyethylene (trade name “Admer NF-539”, Melting point 125 ° C., Mitsui Chemicals Co., Ltd.) 10% by weight, and carbon black (trade name “Printex L”, primary particle size 21 nm, manufactured by Degussa) as three types of conductors Carbon black (trade name “# 10B”, primary particle diameter 79 nm, manufactured by Mitsubishi Chemical Corporation), exfoliated graphite (trade name “UP-10”, manufactured by Nippon Graphite Co., Ltd.) 61% by weight of a combination, 1.5% by weight of a reactive silicone oil (trade name “X-22-4741”, manufactured by Shin-Etsu Silicone Co., Ltd.) as a release agent, and polytetrafluoroethylene (as a dispersion stabilizer) PTFE), an acrylic-modified additive (trade name “Metabrene A3000”, manufactured by Mitsubishi Rayon Co., Ltd.) 2.5% by weight, a titanium-based coupling agent (trade name “Plenact KR-44” as a reactive additive) Ajinomoto Fine Techno Co., Ltd.) 1.0% by weight was prepared by kneading with a kneader. In the above embodiment, exfoliated graphite is used, but when high PTC characteristics are required, spheroidized graphite may be used in combination.

  The covering resistor 9 is 33% by weight of high-density polyethylene (trade name “Nipolon Hard 5700”, melting point 130 ° C., manufactured by Tosoh Corporation) and maleic anhydride-modified linear resin as a maleic anhydride-modified crystalline resin. It is composed of 14% by weight of low-density polyethylene (trade name “Admer NF-539”, melting point 125 ° C., manufactured by Mitsui Chemicals, Inc.), and carbon black (trade name “Printex L”, primary particle diameter) as a conductor. 21%, manufactured by Degussa), conductive whisker (trade name “MPT-256”, manufactured by Ishihara Sangyo Co., Ltd.), and carbon nanotube (trade name “CNT NC7000”, manufactured by Belgium), 50% by weight, dispersed Additives made of polytetrafluoroethylene (PTFE) with acrylic modification as stabilizer (trade name “METABREN A3000”, Mitsubishi Rayon Co., Ltd.) 2.5% by weight, titanium coupling agent (trade name “Plenact KR-44”, manufactured by Ajinomoto Fine Techno Co., Ltd.) 0.5% by weight as a reactive additive. Produced. The reactive additive and the conductor are preliminarily dispersed heat pretreated and subjected to kneading, whereby an extruded product with less foaming can be obtained.

  In the above embodiment, the sheet resistance of the obtained sheet heating element 1 was 25Ω □ (20 ° C., the film thickness of the flame retardant PTC resistor 5 is 100 micrometers). The specific resistance in the case of a two-row arrangement configuration with an area of 300 mm × 350 mm square with 3 mm of flame retardant electrodes (corresponding to a length of 600 mm with 3 mm of flame retardant electrodes) is about 0.25 Ω · cm. there were.

  The film thickness in the calendar process is at least 75 micrometers, and the roll coater process is 10 micrometers. The specific resistance of the carbon black / graphite system used in the flame retardant PTC resistor of this example is considered to be 0.03 Ω · cm. Therefore, addition of metal powder is indispensable for realizing a specific resistance of 0.1 Ω · cm or less, but conduction cannot be ensured unless the metal powder is highly filled. I think it is not applicable to resin compounds used for calendering. Resistor ink used for roll coater processing can be sufficiently applied.

  This time, the obtained PTC resistor 5 has PTC characteristics, and when the temperature rises, the resistance value rises, and it has a self-temperature adjustment function so that it becomes a predetermined temperature, so temperature control is unnecessary and safety It has a function as a high planar heating element 1. It can be used as a car seat heater incorporated in a car seat or a radiation heater for a car. As a planar heating element having PTC characteristics, quick heat and energy saving can be exhibited as compared with a conventional heating element using a tubing heater. A tube heater that uses a heating element requires a temperature controller, and the heating temperature is controlled by controlling energization by ON-OFF control. Since the heater wire temperature at the time of ON rises to about 80 ° C., it is necessary to dispose it at a certain distance from the seat skin material, whereas in the planar heating element of the present invention, the heating temperature is 40 ° C. Since it is self-controlled within a range of ˜60 ° C., it can be arranged close to the seat skin material. The heat generation temperature is low, and it can be used as contact heating with the body to realize energy saving by reducing heat dissipation loss.

  Moreover, 80 degreeC heat resistance evaluation, 150 degreeC heat resistance evaluation, and -20 degreeC and 50 degreeC heat cycle evaluation were implemented for the planar heating element 1 obtained by the present Example. As a result, the resistance value change rate was within 30% of the initial value after 500 hours, 200 hours and 200 times, respectively. Furthermore, the safety | security that the resistance at the time of death by 150 degreeC heat resistance evaluation becomes high was able to be ensured. Factors of stability in heat resistance evaluation include the stabilization effect of the conductor by bonding the titanium coupling agent used as a stabilizer to the conductor surface, the effect of improving the melt tension by the processing aid, Furthermore, it was considered that the penetration of the hot melt adhesive 4 into the PTC resistor 5 and partial compatibilization were caused.

  The conductor is required to achieve a predetermined resistance value with the smallest possible addition amount, but such a conductor is generally called conductive carbon black, and has a primary particle diameter of about 20 nm or less and a structure. (It is an aggregate of primary particles such as a bunch of cocoons. It is correlated with oil absorption.) However, such conductive carbon black has a PTC characteristic on the other hand. It had the disadvantage of being difficult to express. This is because the structure of conductive carbon black is developed, and the conductive path of the structure is not easily cut even by the change in specific volume due to the temperature of the crystalline resin (which is said to be the main cause of the PTC characteristics). It is said. On the other hand, the inventors have obtained as knowledge that carbon black having a large primary particle diameter has excellent PTC characteristics. Further, as the graphite, spherical graphite having a particle diameter larger than that of the above-described carbon black is used. By combining these conductors, the thickness is about 300 micrometers or less, the sheet resistance is 100 Ω □ or less, the specific resistance is 1 Ω · cm or less, and 20 ° C., which is one index of PTC characteristics. A resistor composition having a resistance value ratio of 50 ° C. to a resistance value of 2.5 or more and a resistance value ratio of 80 ° C. to a resistance value of 20 ° C. of 7 or more could be obtained.

  Although the details of the mechanism that has been able to exhibit excellent PTC characteristics despite this low resistance are unknown, the formation of a new conductive path by combining a crystalline resin and a plurality of conductors, and the flame retardant hot melt I think existence is related.

  In the above embodiment, a titanium coupling agent is used as a stabilizer, but the present invention is not limited to this. Aluminum-based coupling agents, silane coupling agents, and chemical crosslinking agents such as organic peroxides can be used. It goes without saying that waxes such as montanic acid partly saponified esters, and plasticizers and dispersants such as other waxes may be used as necessary.

  As the material of the hot melt material, a polyester type is used, but the material is not limited to this. Urethane-based (urethane-based thermoplastic elastomer) or nylon-based (polyamide-based thermoplastic elastomer) may be used.

  Moreover, although it did not mention in particular as a shape of a conductor, you may combine with a whisker or a fiber-shaped thing other than spherical shape and an indefinite shape.

  Furthermore, the planar heating element of the present invention did not mention flame retardancy, but it is possible to add flame retardancy to a PTC resistor or hot melt adhesive to impart flame retardancy. Needless to say. When a sheet heating element is used by being attached to another flame retardant member, for example, a metal plate, or sandwiched, the flame retardant effect of the other flame retardant member is great, making the sheet heating element difficult. It may not be necessary to make it flammable.

As described above, the planar heating element according to the present invention is thin and environmentally friendly, and has PTC characteristics suitable for EV heating and battery heating.

1 Sheet Heating Element 2 Polyester Film A
3 Polyester film B
DESCRIPTION OF SYMBOLS 4 Hot-melt-adhesive agent 5 PTC resistor 6 Nonwoven fabric made from a mesh-like polyester 7 PTC resistor calendar product 8 Electrode 9 Covering resistor 10 Tin plating copper gathered strand 11 Thermal conductive member 12 Calendar roll 14 Calendar product 15 Laminate roll 16 Laminate Goods

Claims (12)

  A non-woven fabric, a PTC resistor bonded to the non-woven fabric in a thin film by calendering, a pair of electrodes electrically connected to the PTC resistor at intervals of 20 mm to 250 mm, the non-woven fabric and the PTC resistor A planar heating element comprising two polyester films covering the electrode from both sides with a hot melt adhesive, and a heat conductive member bonded to at least one outer surface of the polyester film.   The planar heating element according to claim 1, wherein a mesh-like polyester nonwoven fabric having an opening is used as the nonwoven fabric.   A resin composition comprising a low melting crystalline resin having a melting point of at least 100 ° C. and a high melting crystalline resin having a melting point of at least 100 ° C., a conductor comprising at least two types of carbon black, and a release agent; The planar heating element according to claim 1, wherein the PTC resistor is constituted by a dispersion stabilizer and a reactive additive.   The planar heating element according to claim 2, wherein the resin composition comprises a low-melting crystalline resin, a high-melting crystalline resin, and a maleic anhydride-modified crystalline resin.   The resin composition is composed of 0 to 60% low-melting crystalline resin, 30 to 85% high-melting crystalline resin, and 15 to 40% maleic anhydride-modified crystalline resin. The planar heating element according to claim 2 and 3.   3. A planar heating element according to claim 2, wherein the conductor is a combination of carbon black A having a primary particle diameter of 10 to 30 nanometers, carbon black B having a primary particle diameter of 60 to 150 nanometers, and graphite. .   The planar heating element according to claim 6, wherein exfoliated graphite or spheroidized graphite is used alone or in combination as the graphite.   4. A planar heating element according to claim 3, wherein a reactive silicone oil is used as a release agent, acrylic modified polytetrafluoroethylene is used as a dispersion stabilizer, and a coupling agent is used as a reactive additive.   The planar heating element according to claim 1, wherein the electrode is made of a tin-plated copper aggregate stranded wire or a tin-plated copper aggregate stranded wire coated with a covering resistor, and a crystalline polyester resin as a hot melt adhesive.   A coating resistor is formed of a high melting crystalline resin having a melting point of at least 100 ° C., a conductor composed of carbon black, conductive fibers, and carbon nanotubes, a dispersion stabilizer, and a reactive additive. The planar heating element according to claim 9.   The planar heating element according to claim 10, wherein the covering resistor is a pre-treated conductor and a reactive additive.   The planar heating element according to claim 1, wherein one or both of an aluminum film and a plate material are used as the heat conductive member.