JP2010160954A - Surface heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface heater for easily adjusting its calorific value. <P>SOLUTION: The surface heater 1 includes a flexible base material 2, a heating element layer 3 made of a PTC resin composition formed at least on one face of the base material 2, and a first electrode 6 and a second electrode 7 formed in contact with the heating element layer 3. Either the first electrode 6 or the second electrode 7 includes a plurality of split electrodes 7a, 7b, 7 electrically not connected to each other, and the first electrode 6 or the plurality of the split electrodes 7a, 7b, 7c in the second electrode 7 are arrayed along the direction that distance is separated against the other electrode. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a planar heater.

  2. Description of the Related Art Conventionally, a self-temperature control type heating element having a PTC (Positive Temperature Coefficient) characteristic is used as a planar heater used to prevent freezing of automobile seats, door mirrors, floor heating appliances, and water pipes.

  In the heating element having the PTC characteristic, conductive particles such as carbon black are dispersed in a predetermined amount in a resin. This heating element forms conductive paths in the resin and functions as a resistor as a whole, and generates heat using Joule heat generated when a current flows through the conductive paths. And when a heat generating body is heated, the contact state of electroconductive particle will change with expansion | swelling of resin accompanying a temperature change, and resistance value will rise. If it does so, the electric current which flows into a heat generating body will become small, and the emitted-heat amount will also be suppressed, and temperature will not rise more than predetermined temperature. In this way, a planar heater using a heating element having PTC characteristics can be self-temperature controlled.

  In such a planar heater, a heating element layer is provided on a sheet-like substrate, and a pair of electrodes for applying a voltage to the heating element is formed between the substrate and the heating element (for example, , See Patent Document 1).

JP 2001-357966 A

  The calorific value of the planar heater described above is uniquely determined by its shape and the performance of the heating element, and it is difficult to freely adjust the calorific value with one planar heater. In order to obtain a desired amount of heat generated according to the installation location of such a planar heater, the material design of the heating element is mainly optimized. For example, the conductive path is controlled by adjusting the crystallinity of the resin, the content of conductive particles, and the like. For this reason, it is a common practice to develop a variety of heating elements according to a desired amount of heat generation.

  An object of this invention is to provide the planar heater which can adjust the emitted-heat amount easily.

  In order to achieve the above object, a planar heater according to the present invention includes a flexible base material, a heating element layer made of a PTC resin composition formed on at least one surface of the base material, A planar heater comprising a first electrode and a second electrode formed in contact with the heating element layer, wherein one of the first electrode and the second electrode is a plurality of electrically non-connected ones The plurality of divided electrodes in the first electrode or the second electrode are arranged along a direction away from the other electrode.

  According to the planar heater according to the present invention, either the first electrode or the second electrode formed in contact with the heating element layer has a plurality of divided electrodes that are not electrically connected to each other. A plurality of divided electrodes in the first electrode or the second electrode are arranged along a direction in which the distance from the other electrode is increased. For this reason, if one divided electrode is selected as one electrode for applying a voltage to the heating element layer from a plurality of divided electrodes in the first electrode or the second electrode, a pair of electrodes for applying a voltage to the heating element layer, that is, The distance between the first electrode and the second electrode can be arbitrarily selected. Since the heat generation amount of the heating element layer depends on the resistance value, in other words, the distance between the electrodes, it can be adjusted to a desired heat generation amount by simply selecting a divided electrode as one electrode. As a result, the calorific value can be easily adjusted.

  In the planar heater according to the present invention, it is preferable that the plurality of divided electrodes are provided at regular intervals. Thereby, adjustment of the calorific value is further facilitated.

  In the planar heater according to the present invention, it is preferable that the plurality of divided electrodes and the other electrode in the first electrode or the second electrode are formed substantially parallel to each other. Thereby, adjustment of the calorific value is further facilitated.

  In the planar heater according to the present invention, it is preferable that the first electrode is formed on one surface side of the heating element layer and the second electrode is formed on the other surface of the heating element layer. As a result, compared to the case where the first electrode and the second electrode are formed on one side of the heating element layer, the current easily flows through the conductive path formed in the entire heating element layer, and the entire heating element layer generates heat. A larger calorific value can be secured.

  ADVANTAGE OF THE INVENTION According to this invention, the planar heater which can adjust calorific value easily can be provided.

It is the schematic perspective view which fractured | ruptured partially the planar heater which concerns on this embodiment. It is sectional drawing in the II-II line direction in FIG. It is a figure which shows the characteristic of the planar heater which concerns on a present Example. It is sectional drawing which shows the structure of the planar heater which concerns on other embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a schematic perspective view in which the planar heater 1 according to the present embodiment is partially broken. 2 is a cross-sectional view taken along the line II-II in FIG.

  As shown in FIGS. 1 and 2, the planar heater 1 includes a base material 2, a heating element layer 3, a pair of electrodes 4, and an insulator layer 5.

  The base material 2 is an insulating sheet having flexibility, and for example, polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) is used. This base material 2 is for holding the heating element layer 3 and insulatingly protecting it from the outside, and its outer shape is appropriately determined according to the installation location of the planar heater 1. In the present embodiment, the sheet is a rectangular sheet, but the sheet is not limited to this. Moreover, this thickness is suitably determined according to the installation place of the planar heater 1 like the external shape, and is about 500-1000 micrometers.

  The heating element layer 3 is a portion that generates heat, and is formed on one surface of the substrate 2 inside the outer shape. In the present embodiment, the outer shape is rectangular like the base material 2, but is not limited thereto, and may be, for example, a circular shape, an elliptical shape, a belt shape, or the like. The thickness of the heating element layer 3 is appropriately determined according to the output and is 1 mm or more. If the thickness of the heating element layer 3 is too thin, the PTC characteristics are liable to deteriorate and the self-temperature control becomes difficult.

  The heating element layer 3 is made of a PTC resin composition containing a resin exhibiting PTC characteristics, that is, a resin, and conductive particles dispersed in the resin.

  As the resin, a crystalline resin is used, and examples thereof include polyolefin resin, polyamide resin, polyacetal resin, polyester resin, and fluorine resin.

  Examples of the polyolefin resin include polyethylenes such as high density polyethylene, medium density polyethylene, low density polyethylene, and linear low density polyethylene, polypropylenes such as isotactic polypropylene and syndiotactic polypropylene, polybutene, and 4-methylpentene. -1 resin. Examples of the polyamide-based resin include nylon 6, nylon 8, nylon 11, nylon 66, nylon 610, and the like. The polyacetal resin may be a homopolymer based on a monomer or a copolymer based on two or more monomers. Examples of the polyester resin include polyethylene terephthalate and polybutylene terephthalate. Examples of the fluororesin include polyvinylidene fluoride (PVDF), ethylene-tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), and the like. It is done.

  Among these, fluororesin, PFA, PVDF and the like can be preferably used from the viewpoint of heat resistant temperature. These crystalline resins may be used alone or in a combination of two or more.

Examples of the conductive particles include carbon particles such as carbon black particles and graphite particles, and metals such as iron (Fe), nickel (Ni), platinum (Pt), copper (Cu), silver (Ag), and gold (Au). Particles, tin-added indium oxide (Indium-Tin-Oxide: ITO), tin oxide (SnO ₂ ), fluorine-added tin oxide (Fluorine-Tin-Oxide: FTO), antimony-added tin oxide (Antimony-Tin-Oxide: ATO) And conductive metal oxide particles such as zinc oxide (ZnO).

  Among these, carbon-based particles are preferable from the viewpoints of ease of self-temperature control, cost, and light weight compared to metal particles and the like.

  The average particle diameter of these conductive particles is not particularly limited. For example, the average particle diameter is preferably 30 to 90 nm from the viewpoint of electrical conductivity, and particularly preferably 45 to 60 nm. From the viewpoint of obtaining the resistance of the heating element layer 3, it is more preferable. In addition, an average particle diameter is a value at the time of measuring by observation by SEM.

  Further, the content of the conductive particles in the heating element layer 3 is not particularly limited, but for example, 3 to 30% by mass is preferable from the viewpoint of obtaining the resistance of the heating element layer 3.

  The insulator layer 5 is for insulating and protecting the heating element layer 3 from the outside, and is provided so as to cover the heating element layer 3 and a pair of electrodes 4 described later. This insulator layer 5 may be adhered so as to cover the heating element layer 3 and the pair of electrodes 4 by using a flexible insulating sheet such as PET or PEN as in the case of the substrate 2. It may be formed by applying a body paste.

  The insulator paste includes an insulator material and a curing agent, and examples of the insulator material include resins such as epoxy and polyimide. As the curing agent, it is preferable to use an ultraviolet curing agent because it does not give a heat load.

  The electrode 4 is provided on one surface of the heating element layer 3 and on the insulator layer 5 side, and has a first electrode 6 and a second electrode 7. The first electrode 6 and the second electrode 7 form a pair, and a voltage is applied to the heating element layer 3 through the first electrode 6 and the second electrode 7.

  The electrode 4 may be formed by bonding a metal foil made of a metal material such as Cu, Ag, Au, or Pt, or by printing an electrode paste made of these metal materials.

  The first electrode 6 has a rectangular shape extending along one side (in the y direction in the figure) of the rectangular heating element layer 3, and is provided in a region on one side of the heating element layer 3. The first electrode 6 is provided so as to cover only one side surface of the heating element layer 3 without covering the entire surface of the heating element layer 3. A first electrode pad 61 drawn from the first electrode 6 is provided on the surface of the substrate 2 on one end side of the first electrode 6.

  On the other hand, the second electrode 7 is provided on the same surface as the surface on which the first electrode 6 in the heating element layer 3 is provided, and is provided in a region on the other side of the first electrode 6.

  Further, the second electrode 7 includes a plurality of divided electrodes 7a, 7b, and 7c that are electrically independent from each other. Each of the divided electrodes 7a, 7b, and 7c has a rectangular shape extending along one side (in the y direction in the drawing) of the rectangular heating element layer 3 in the same manner as the first electrode 6. Are arranged along the direction (x direction in the drawing) away from each other, that is, the direction connecting both sides of the heating element layer 3. The divided electrodes 7 a, 7 b, 7 c are spaced apart from each other at equal intervals and are arranged substantially in parallel with each other, and are also arranged substantially in parallel with the first electrode 6. Each of the divided electrodes 7a, 7b, 7c is provided with second electrode pads 71a, 71b, 71c drawn from the divided electrodes 7a, 7b, 7c on the surface of the substrate 2 on one end side. ing.

  In the present embodiment, the electrode is composed of three divided electrodes, but is not particularly limited as long as it is two or more divided electrodes.

  Then, the usage method about the planar heater 1 which concerns on this embodiment is demonstrated. The case where the voltage V1 applied between the first electrode and each second electrode is constant will be described.

  When a voltage V1 is applied from a power source (not shown) to the first electrode 6 through the first electrode pad 61 of the planar heater 1 and the divided electrode 7a as the second electrode through the second electrode pad 71a, the first electrode A current flows between 6 and the divided electrode 7a. Then, the heating element layer 3 has a predetermined heat generation amount from the resistance value corresponding to the distance T1 between the first electrode 6 and the divided electrode 7a, and the output W1 is obtained from the planar heater 1.

  Similarly, when a voltage V1 is applied from a power source (not shown) to the first electrode 6 via the first electrode pad 61 of the planar heater 1 and the divided electrode 7b which is the second electrode via the second electrode pad 71b. A current flows between the first electrode 6 and the divided electrode 7b. If it does so, the heat generating body layer 3 will become predetermined | prescribed calorific value from the resistance value according to the distance T2 of the 1st electrode 6 and the division | segmentation electrode 7b, and the output W2 smaller than W1 from the planar heater 1 will be obtained.

  Further, when a voltage V1 is applied from a power source (not shown) to the first electrode 6 through the first electrode pad 61 of the planar heater 1 and the divided electrode 7c as the second electrode through the second electrode pad 71c, A current flows between the one electrode 6 and the divided electrode 7c. If it does so, the heat generating body layer 3 will become a predetermined calorific value from the resistance value according to the distance T3 of the 1st electrode 6 and the division | segmentation electrode 7c, and the output W3 smaller than W2 from the planar heater 1 will be obtained.

  In addition, even if it is the same planar heater 1, if it adjusts so that the electric current value which flows between each electrode of 1st electrode 6 and each divided electrode 7a, 7b, 7c which is the 2nd electrode may become constant, As the distance between the electrodes increases, a large output can be obtained.

  As described above, according to the planar heater 1 according to the present embodiment, the second electrode 7 formed in contact with the heating element layer 3 has a plurality of divided electrodes 7a, 7b, 7c that are not electrically connected to each other. A plurality of divided electrodes 7 a, 7 b, 7 c in the second electrode 7 are arranged along the direction in which the distance from the first electrode 6 is increased. For this reason, if one divided electrode is selected as one electrode for applying a voltage to the heating element layer 3 from the plurality of divided electrodes 7a, 7b, 7c in the second electrode, a pair of voltages for applying a voltage to the heating element layer 3 is selected. The distance between the electrode 4, that is, the first electrode 6 and the second electrode 7 can be arbitrarily selected. Since the heat generation amount of the heating element layer 3 depends on the resistance value, in other words, the distance between the electrodes, it can be adjusted to a desired heat generation amount by simply selecting the divided electrodes 7a, 7b, 7c as one electrode. can do. As a result, the calorific value can be easily adjusted.

  Further, the planar heater 1 according to the present embodiment is provided with a plurality of divided electrodes 7a, 7b, 7c spaced apart from each other at equal intervals. Thereby, adjustment of the calorific value is further facilitated.

  Further, in the planar heater 1 according to the present embodiment, the plurality of divided electrodes 7a, 7b, 7c in the first electrode and the second electrode are formed substantially parallel to each other. Thereby, adjustment of the calorific value is further facilitated.

  Next, it will be described that the adjustment of the calorific value is easy while showing specific examples.

  In the planar heater shown in FIG. 1, a second electrode having six divided electrodes was prepared. Here, the distance from the first electrode to each divided electrode was set to 1, 2, 4, 6, 8, and 10 cm, respectively. Moreover, the thickness of the heating element layer was 2 mm, and the outer shape thereof was a rectangular shape having a length (dimension in the y direction in FIG. 1) 120 mm × width (dimension in the x direction in FIG. 1) 120 mm.

  In addition, the heating element layer was prepared by pelletizing PVDF (trade name Hyrar 460; manufactured by Solvay) and carbon black (trade name Vulcan XC72; manufactured by Cabot) using a twin-screw kneader and using an electrothermal press. . The electrode was formed by applying a conductive paste (trade name Doutite D-500; manufactured by Fujikura Kasei Co., Ltd.), drying and heating.

  A constant voltage of 20 V was applied to the planar heater between the first electrode and each divided electrode, and the output was calculated from the current value and resistance value when the planar heater temperature became constant. The exothermic temperature was observed using a thermo camera.

  The result is shown in FIG. FIG. 3 is a diagram showing the characteristics of the planar heater according to the present example, and shows a change in output with respect to the distance between the electrodes. The output was calculated from the measured calorific value and the distance between each electrode. At the same time, the resistance value is also shown.

  As a result, in this example, it was confirmed that by applying a constant voltage between the electrodes, the output changes according to the distance between the electrodes, that is, the output decreases according to the distance.

  Next, a method for manufacturing the planar heater 1 according to this embodiment will be described.

  First, a resin composition-containing liquid containing a resin and conductive particles is prepared. For example, a crystalline resin is used as the resin. In the preparation, first, conductive particles that have been previously dried are added to the resin, and the mixture is stirred and mixed using a stirring means such as a ball mill. And heat processing is performed with stirring and mixing, and melt kneading is performed. At this time, the temperature of the heat treatment is preferably a temperature equal to or higher than the melting point of the crystalline resin. And the obtained resin composition is shape | molded into a predetermined-shaped sheet | seat, for example using an electrothermal press, and the heat generating body layer 3 is produced.

  Next, for example, copper foil is bonded to predetermined positions on both surfaces of the heating element layer 3 to form the electrodes 4. Furthermore, for example, a base material made of PET having a larger outer shape than the heating element layer 3 is bonded to one surface side of the heating element layer 3 on which the electrode 4 is formed, and the heating element layer 3 and the electrode 4 are further bonded to the other surface side. Insulating layer 5 is formed by applying and drying an insulating paste containing, for example, an epoxy resin, a polyimide resin, a solvent, or the like so as to cover it. Note that an insulating sheet may be formed by laminating with an adhesive.

  Finally, the first electrode pad 61 and the second electrode pad 71 drawn from each electrode 4 are formed on the substrate by applying and drying an electrode paste. Thus, the planar heater 1 is obtained.

  Then, the planar heater 10 which concerns on other embodiment is demonstrated. FIG. 4 is a cross-sectional view showing the structure of a planar heater according to another embodiment.

  The planar heater 10 is a partial region on the other surface side where the second electrode is opposite to the one surface where the first electrode 6 in the heating element layer 3 is provided with respect to the planar heater 1 according to the embodiment described above. It is the same structure except having been formed.

  As described above, according to the planar heater 10 according to another embodiment, the first electrode 6 is formed on one surface side of the heating element layer 3 and the second electrode 7 is the other surface of the heating element layer 3. Formed. Thereby, compared with the case where the 1st electrode 6 and the 2nd electrode 7 are formed in the single side | surface of the heat generating body layer 3, since an electric current flows easily over the heat generating body layer 3 whole, and the heat generating body layer 3 whole heat | fever-generates, A large calorific value can be secured.

  The planar heater according to the present invention is not limited to this embodiment. In the said embodiment, although the 2nd electrode 7 has several division | segmentation electrode 7a, 7b, 7c, the 1st electrode 6 may have a division | segmentation electrode.

  DESCRIPTION OF SYMBOLS 1,10 ... Planar heater, 2 ... Base material, 3 ... Heat generating body layer, 4 ... Electrode, 5 ... Insulator layer, 6 ... First electrode, 7 ... Second electrode, 7a, 7b, 7c ... Divided electrode, 61 ... 1st electrode pad, 71 ... 2nd electrode pad.

Claims (4)

A flexible substrate, a heating element layer made of a PTC resin composition formed on at least one surface of the substrate, a first electrode and a second electrode formed in contact with the heating element layer, A planar heater comprising:
Either the first electrode or the second electrode has a plurality of divided electrodes that are not electrically connected to each other, and the plurality of divided electrodes in the first electrode or the second electrode are the other A planar heater, characterized in that the heater is arranged along a direction in which the distance from the electrode is increased.   The planar heater according to claim 1, wherein the plurality of divided electrodes are provided at regular intervals.   The planar heater according to claim 1 or 2, wherein the plurality of divided electrodes and the other electrode of the first electrode or the second electrode are formed substantially parallel to each other.   The planar heater according to claim 1, wherein the first electrode is formed on one surface side of the heating element layer, and the second electrode is formed on the other surface of the heating element layer. .

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