JP2010257685A - Planar heating element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve durability of a planar heating element with enhanced flexibility. <P>SOLUTION: The planar heating element includes an electrically insulating base material 2 having flexibility; at least a pair of linear electrodes 3 including a conductive coating whose main component is resin composition and conductive material; and a polymer resistor 4, whose main component is resin composition and conductive material. The polymer resistor 4 is electrically connected to the pair of linear electrodes 4 and is mechanically jointed to the electrically insulating base material 2 and the pair of linear electrodes 3. Thus the three-layer structure consisting of the electrically insulating base material 2, at least a pair of electrodes, and a polymer resistor is facilitated in exhibiting flexibility. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a planar heating element that is flexible and has high reliability and PTC characteristics.

  Conventionally, in this type of planar heating element, a heating element is used that is produced by printing, drying, and firing a resistor ink in which a heating part is dispersed in a base polymer and a conductive material in a solvent. This resistor generates heat when energized.

  In this type of resistor, carbon black, metal powder, graphite, or the like is generally used as a conductive substance, and a crystalline resin is used as a base polymer. With such a material, the heat generating portion exhibits PTC characteristics.

  8 and 9 show a specific configuration of a conventional planar heating element. The planar heating element 51 includes a substrate 52, a pair of comb-shaped electrodes 53 and 54, a polymer resistor 55, a covering. Material 56.

  The electrically insulating base 52 is made of a resin such as a polyester film. The comb-shaped electrodes 53 and 54 are formed on a substrate 52 by printing and drying a conductive paste such as a silver paste.

  The polymer resistor 55 is formed by printing and drying polymer resistor ink at a position where power is supplied by the comb-shaped electrodes 53 and 54. A covering material 56 made of the same material as the base material 52 covers and protects the comb-shaped electrodes 53 and 54 and the polymer resistor 55.

  When using a polyester film as the base material 52 and the covering material 56, for example, a heat-fusible resin 57 such as modified polyethylene is bonded to the covering material 56 in advance. And it pressurizes, giving heat.

  By doing in this way, the base material 52 and the covering material 56 are joined via the heat-fusible resin 57.

  The covering material 56 and the heat-fusible resin 57 isolate the comb-shaped electrodes 53 and 54 and the polymer resistor 55 from the outside. Therefore, long-term reliability is imparted to the planar heating element 51.

  FIG. 10 shows an apparatus for bonding the covering material 56 together. As a method of heating and pressing, a laminator 60 composed of two heating rolls 58 and 59 is generally used.

  That is, a base material 52 on which comb-shaped electrodes 53 and 54 and a polymer resistor 55 are formed in advance and a coating material 56 on which a heat-fusible resin 57 is bonded in advance are supplied, and these are heated by heating rolls 58 and 59. Heat and pressurize.

  In this way, the planar heating element 51 is produced.

  The PTC characteristic means a resistance temperature characteristic in which the resistance value increases as the temperature rises, and the resistance value increases rapidly when a certain temperature is reached. The polymer resistor 55 having PTC characteristics can give the planar heating element 51 a self-temperature adjusting function (see, for example, Patent Document 1).

  Also, a PTC composition comprising amorphous polymer, crystalline polymer particles, conductive carbon black, graphite, and an inorganic filler is dispersed in an organic solvent, an ink is prepared, and then a PTC composition is formed on a resin film provided with electrodes. There is also a planar heating element in which a polymer resistor is printed with a physical ink, heat treatment for crosslinking is performed, and a resin film is laminated as a protective layer of the polymer resistor (see, for example, Patent Document 2).

  Further, in the planar heating element 61 shown in FIG. 11, electrodes 63 and 64 and a polymer resistor 65 are sequentially laminated on a flexible base material 62 by a printing method, and a flexible coating layer 66 is further formed. ing.

  The flexible base material 62 has a function of impregnating a liquid such as gas barrier property and waterproof property, polymer resistor ink, etc., and a polyester non-woven fabric composed of long fibers and a hot surface such as polyurethane on the surface of the polyester non-woven fabric. The melt film is laminated.

  On the other hand, the flexible coating layer 66 has gas barrier properties and waterproof properties, and covers the electrodes 63 and 64 and the entire polymer resistor 65. The polyester nonwoven fabric and the surface of the polyester nonwoven fabric are hot-melted such as polyester. This is a structure in which films are bonded together, and is bonded to a flexible base material 62.

  Therefore, the planar heating element 61 shown in FIG. 11 has a six-layer structure in total (see, for example, Patent Document 3).

Japanese Patent Laid-Open No. 56-13689 JP-A-8-120182 US Pat. No. 7,049,559

  In the conventional planar heating element 51 of Patent Documents 1 and 2, a rigid material such as a polyester film is used as the substrate 52. Further, a five-layer structure composed of a base material 52, comb-shaped electrodes 532 and 54 printed thereon, a polymer resistor 55, and a covering material 56 having an adhesive layer disposed thereon. Have

  Therefore, depending on the material and the thickness of the base material 52 and the covering material 56, it becomes inflexible, and when this planar heating element 51 is mounted on a car seat device for heating, the seating feeling is impaired, In addition, when used in a handle heater, the touch feeling is impaired.

  Further, since the shape is planar, when a load due to seating or the like is applied to a part of the surface, the force is exerted on the entire surface and the planar heating element 51 is deformed. Depending on the shape of the deformation, the closer to the end of the sheet heating element 51, the larger the deformation amount, and a crease or the like occurs in a part of the surface.

  There is a possibility that cracks or the like occur in the comb-shaped electrodes 53 and 54 and the polymer resistor 55 in the folded portion, and the durability is lowered.

  Further, since the base material 52 and the covering material 56 such as a non-breathable polyester sheet are used, moisture tends to be accumulated when used for a seat device or a handle, and the seating feeling and the touch feeling are impaired when used for a long time. It was a thing.

  On the other hand, the planar heating element 61 of Patent Document 3 has a flexible base material and covering layer for the electrodes 63 and 64 and the polymer resistor 65, so that it can be seated even when used for a seat device or a handle of an automobile. Although the feeling and the touch feeling are good, the sheet heating element 61 has a six-layer structure, so that the productivity is poor and the cost is increased as a result.

  The present invention solves the above-described conventional problems, and is easy to exhibit flexibility even when an external force is applied, improves seating feeling and touch feeling, and is low-cost planar heat generation excellent in durability and reliability. The purpose is to provide a body.

  In order to solve the above-described conventional problems, the planar heating element of the present invention has at least one electrically insulating base material having flexibility and a conductive coating whose main component is a resin composition and a conductor. A pair of filament electrodes and a polymer resistor composed mainly of a resin composition and a conductor. The polymer resistor is electrically connected to the pair of filament electrodes and the electric The insulating base material and the pair of filament electrodes are mechanically joined.

  Therefore, since it is comprised by the 3 layer structure of an electrically insulating base material, an at least 1 pair of electrode, and a polymer resistor, it can make it easy to exhibit a softness | flexibility.

  The planar heating element of the present invention has a three-layer structure with respect to the conventional planar heating element of 5-6 layers, and is provided with a conductive coating on the filament electrode, so that the flexibility is greatly increased. Durability and reliability can be improved.

The top view which shows the planar heating element in Embodiment 1 of this invention XY sectional view of FIG. 1 is a side view of an automobile seat device equipped with the sheet heating element according to the first embodiment. Front view of the car seat device Explanatory drawing which shows the PTC expression mechanism at the time of using a granular conductor Characteristics of sheet heating element Schematic diagram of a device for evaluating the characteristics of sheet heating elements Plan view of a conventional planar heating element XY sectional view of FIG. Sectional drawing which shows schematic structure of the preparation apparatus of the conventional planar heating element Sectional view of another conventional sheet heating element

  According to a first aspect of the present invention, there is provided an electrically insulating base material having flexibility, at least a pair of linear electrodes having a conductive coating composed mainly of a resin composition and a conductor, and a resin composition comprising a main component. And a polymer resistor composed of a conductor and electrically connecting the polymer resistor to the pair of filament electrodes, and the electrically insulating substrate and the pair of filament electrodes By adopting a mechanically bonded configuration, a conventional layered heating element can be made into a three-layer structure from the five- to six-layer structure of the planar heating element, so that flexibility can be easily exhibited.

  Therefore, even when an external force is applied when used as a car seat heater, the polymer resistor can be easily deformed, and cracking and peeling of the polymer resistor caused by creases can be prevented.

In addition, by having a configuration in which the filament electrode has a conductive coating, when an external force is applied, the filament electrode can be protected even if severe stress such as bending is applied, and the disconnection can be prevented. it can.

  In addition, since a resin film such as a non-breathable polyester sheet is not used with a polymer resistor in between, moisture tends to be trapped when used for car seat heaters and handle heaters like conventional planar heating elements. This solves the problem, and even when used for a long time, a seating feeling and a touch feeling equivalent to those in the initial stage can be obtained, and a comfortable heating effect can be obtained.

  Furthermore, since the planar heating element can be produced with a simple structure of three layers, it is excellent in productivity and, as a result, can be produced at low cost.

  In addition, since the electrode is composed of a filament, it can be configured simply, unlike the conventional complicated comb-shaped electrode.

  Therefore, the cost of the electrode material can be reduced, and even when an external force is applied when used in an automobile seat device or the like, generation of wrinkles of the electrode is suppressed, and damage to the electrode material can be prevented.

  In the second invention, in particular, in the first invention, the wire electrode is composed of at least one of a metal conductive wire and a metal braided conductive wire, so that it is easy to sew to the electric base material insulation or polymer resistor. Thus, productivity is improved.

  Moreover, the selection range of the material and shape of the metal conductor and the metal braided conductor is expanded. Further, since the metal conductor and the metal braided conductor are excellent in flexibility and have high mechanical strength, they can endure for a long time even if the planar heating element is repeatedly elongated, bent, or deformed.

  In particular, according to the third invention, in the first invention, when the conductive coating (1) blows the end face of the electrically insulating substrate with a gas flame and extinguishes the gas flame after 60 seconds, the electrically insulating substrate Even if the material is burnt, the electrically insulating substrate itself does not burn. (2) The end face of the electrically insulating substrate is blown by a gas flame, and once the electrical insulating substrate is ignited, within 60 seconds, and 2 inches. (3) The end face of the electrically insulating substrate is blown by a gas flame, and even if the electrically insulating substrate is ignited, the flame is 4 inches / minute in the region of 1/2 inch thickness from the surface. By further including a flame retardant that imparts flame retardancy that satisfies at least one of the conditions of not proceeding at the above speed, the flame retardancy of the planar heating element can be improved, and the safety of heaters and applied products Can increase the sex.

  In particular, the fourth invention is the one according to the third invention, wherein the flame retardant is liquid at room temperature or has a melting point that melts at the kneading temperature, and uses at least one of phosphorus, nitrogen, and silicone compounds. In this way, flame resistance can be imparted without impairing the flexibility of the electrically insulating substrate and polymer resistor, and the safety of the planar heating element and its applied products can be improved. Mechanical durability and reliability as a planar heating element are ensured.

  In particular, according to a fifth aspect of the present invention, in the first aspect, when the electrically insulating base material (1) blows the end face of the electrically insulating base material with a gas flame and extinguishes the gas flame after 60 seconds, Even if the insulating base material is burnt, the electrically insulating base material itself does not burn. (2) The end face of the electrically insulating base material is blown by a gas flame, and once the electrically insulating base material is ignited, within 60 seconds, Fire extinguishing within 2 inches. (3) The end face of the electrically insulating substrate is blown with a gas flame, and even if the electrically insulating substrate is ignited, the flame is 4 inches in the region of 1/2 inch from the surface. By imparting flame retardancy satisfying at least one of the conditions of not proceeding at a rate of at least / min, it is possible to improve the flame retardancy of the planar heating element without adding a flame retardant in particular. The safety of applied products can be increased.

In the sixth invention, in particular, in the first invention, it is not necessary to add a flame retardant by using at least one of a metal, a metal oxide, a metal carbide, a metal nitride, and a metal boride as the conductor. In addition, the flame resistance can be imparted without impairing the flexibility of the electrically insulating base material and polymer resistor, and the safety of the planar heating element and its applied products can be improved. Mechanical durability and reliability as a heating element are ensured.

  In the seventh invention, in particular, the planar heating element according to any one of the first to sixth inventions is mounted on an automobile seat device. Is relaxed and does not impair the seating feeling.

  According to an eighth invention, in the seventh invention, the electrically insulating base material of the planar heating element is arranged so as to be on the surface side of the seat portion and the backrest.

  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)
As shown in FIGS. 1 and 2, the planar heating element 1 includes an electrically insulating substrate 2, a first filament electrode 3 </ b> A, a second filament electrode 3 </ b> B, and a polymer resistor 4. . The linear electrodes 3A and 3B may be collectively described as the linear electrode 3 in some cases.

  The linear electrodes 3A and 3B are arranged on the electrically insulating base material 2 so as to be symmetric with respect to each other, and are partially sewn with the thread 5, and the main components are a resin composition and a conductor. It is covered with a conductive coating 6.

  The polymer resistor 4 is formed on the electrically insulating substrate 2 on which the filament electrodes 3 are arranged by being extruded into a film by, for example, a T-die extrusion method.

  The central portion of the sheet heating element 1 is punched after the polymer resistor 4 is thermally fused to the linear electrode 3 and the electrically insulating base material 2.

  In addition, the lead wire for supplying the electric power from a power supply to the filament electrodes 3A and 3B is not illustrated. Further, the punching of the central portion is not limited to this place. In this case, the wiring pattern of the line electrode 3 is changed.

  3 and 4 show an automobile seat device in which the sheet heating element 1 is mounted as a heating heat source. The seat 7 and the backrest 8 are arranged with the electrically insulating base material 2 set on the surface side. Yes.

  A seat base 9 and a skin 10 are used for the seat 7 and the backrest 8, and the seat base 9 such as a urethane pad is deformed when a load is applied by a seated human body, and the load is not applied. And the shape is restored.

  The skin 10 covers the seat base material 9. That is, the planar heating element 1 is attached by arranging the polymer resistor 5 side on the seat base material 9 and the electrically insulating base material 2 side on the skin 10.

  In addition, in order to correspond to the hanging part (not shown) of the seat part 7 and the backrest 8, the extension part (not shown) of the electrically insulating base material 2 for hanging in the center part or the peripheral part is provided. There may be.

  Thus, the thin planar heating element 1 is disposed along the seat base 9 and the skin 10 that can be deformed. Therefore, the planar heating element 1 must also undergo similar deformation corresponding to the deformation of the seat 7 and the backrest 8.

  Therefore, it is necessary to design various heat generation patterns and to change the arrangement shape of the line electrodes 3 for that purpose.

  A pair of wide linear electrodes 3 </ b> A and 3 </ b> B arranged so as to face each other are disposed along the outer side in the longitudinal direction of the planar heating element 1. By supplying power from the linear electrodes 3A and 3B to the polymer resistor 4 disposed so as to overlap the linear electrodes 3A and 3B, a current flows through the polymer resistor 4 to generate heat.

  The polymer resistor 4 has PTC characteristics, and has a self-temperature adjusting function so that the resistance value increases as the temperature rises to reach a predetermined temperature. That is, the polymer resistor 4 gives the planar heating element 1 a function that is highly safe and does not require temperature control.

  The PTC expression mechanism of the polymer resistor 4 is assumed as follows.

  5, (a) and (b) show the case where a granular conductor such as carbon black is used, and (c) and (d) show the case where a fibrous conductor is used. The states where the temperature has increased from the states (a) and (c) are (b) and (d), respectively.

  In the polymer resistor 32 using the granular conductor 31 such as carbon black as the conductor, the granular conductor 31 has an aggregate structure of primary particles as shown in FIG. A conductive path in a state where the grains are in point contact with each other is formed. When a current is applied between the electrodes 34 and 35, the polymer resistor 32 generates heat due to the conductive path of the granular conductor 31, and the specific volume of the resin composition 33 changes, so that it is sensitively conductive as shown in FIG. Path disconnection occurs. In this way, a positive resistance temperature characteristic having an abrupt increase in resistance value is manifested.

  On the other hand, the polymer resistor 37 using the fibrous conductor 36 as the conductor does not have an aggregate structure of primary particles such as carbon black as shown in FIG. A conductive path is formed so as to overlap with each other. Also in this structure, when a current is applied between the electrodes 34 and 35, the polymer resistor 32 generates heat by the conductive path of the fibrous conductor 36 as shown in (d), and the specific volume of the resin composition 33 changes. Therefore, the conductive path is cut more sensitively. In this way, a positive resistance temperature characteristic having an abrupt increase in resistance value is manifested.

  The polymer resistor 4 of the present embodiment can be applied to either type described above. As the conductor used, the above-described carbon black can be used for the granular conductor 31, and for the fibrous conductor 36, conductive ceramic fibers tin-plated titanium oxide and doped with antimony, potassium titanate system. Conductive ceramic whiskers, metal fibers such as copper and aluminum, metal-plated glass fibers having a conductive layer formed on the surface, carbon fibers, carbon nanotubes, and fibrous conductive polymers made of polyaniline.

  Further, a flaky conductor may be used instead of the fibrous conductor 36.

  Examples of the flaky conductor include ceramic flakes such as mica flakes having a conductive layer formed on the surface, metal flakes such as copper and aluminum, and scaly graphite.

  The above-mentioned conductors can be used alone or in combination of two or more, and are appropriately selected according to the target PTC characteristics.

The resin composition 33 of the polymer resistor 4 suppresses the change with time of the PTC characteristics and is stable PTC.
In order to reproduce the characteristics, it is preferable to mix a modified polyethylene having a carboxyl group as a reaction resin that expresses PTC and a modified polyethylene having an epoxy group as a reactive resin that reacts with the reaction resin.

  This is because the carbonyl group of the reactive resin reacts with the oxygen of the epoxy group of the reactive resin to be chemically bonded and has a crosslinked structure.

  By this cross-linking reaction, the thermal stability can be increased as compared with the case of the reactive resin alone, and as a result, the temperature at which the conductive path of the conductor in the resin composition 33 is formed and cut is stabilized.

  This cross-linking reaction can occur even through nitrogen in addition to oxygen. If a combination of a reactive resin having a functional group containing at least one of oxygen and nitrogen and a reactive resin having a functional group capable of reacting with these functional groups, a crosslinking reaction will occur, and the resin composition As a combination of the reactive functional group of the reactive resin 33 and the functional group of the resin to be reacted, there are the following in addition to the above-described epoxy group and carbonyl group.

  The epoxy group undergoes addition polymerization by reacting with a carbonyl group such as a maleic anhydride group, an ester group, a hydroxyl group, an amino group, or a vinyl group in addition to the carbonyl group of the carboxylic acid described above. A reaction resin having these functional groups may be used.

  Moreover, as a functional group of the reactive resin, a reactive resin having an oxazoline group or a maleic anhydride group in addition to an epoxy group can be used.

  Thus, the resin composition 33 has a structure crosslinked through at least one of oxygen and nitrogen.

  As described above, when the resin composition 33 includes the reactive resin and the reactive resin exhibiting the PTC characteristic, the conductor is captured by the adhesive force and bonding force of the reactive resin, and the reactive resin and the coated resin are further captured. The conductive path by the fibrous conductor 39 is stabilized by the bonding force with the reactive resin.

  When the heat generation temperature is relatively low as 40 to 50 ° C. as in an automobile seat device, a modified olefin resin that is a low melting point resin such as ethylene vinyl acetate copolymer is used as a reaction resin that exhibits PTC characteristics. It is preferable to use ester-based ethylene copolymers such as ethylene ethyl acrylate copolymer, ethylene methyl methacrylate copolymer, ethylene methacrylic acid copolymer, and ethylene butyl acrylate.

  The reactive resin and the reactive resin of the resin composition 33 described above can be used alone or in combination, and are appropriately selected according to the target PTC characteristics. In addition, it is also possible to use a reactive resin or a reactive resin alone depending on the allowable range of change with time in PTC characteristics.

  Moreover, although the reactive resin was used for the crosslinking reaction of the resin composition 33, the crosslinking agent different from reactive resin can also be used.

  Furthermore, crosslinking means such as an electron beam can be used. In that case, the above-described reactive resin having no functional group is applicable, and it is not necessary to use a reactive resin.

  Moreover, it is preferable to make the resin composition 33 of the polymer resistor 4 contain a liquid-resistant resin. Thereby, the polymer resistor 4 can be given liquid resistance.

  Liquid resistance refers to stable resistance when liquid chemicals such as engine oil, which is nonpolar oil, brake oil, which is polar oil, and organic solvents, such as thinner, which is a low molecular weight solvent, are in contact with each other. It means that the nature is high.

  When the above-mentioned liquid chemical substance comes into contact with the polymer resistor 4, the resin composition 33 containing a large amount of amorphous resin easily swells and changes its specific volume, and the conductive path of the conductor is cut to cause resistance. Shows a trend of increasing values.

  This phenomenon is similar to the change in specific volume due to heat (PTC characteristics). However, when a resin composition having no liquid resistance is used as the polymer resistor 4 and swollen with a liquid chemical substance, the polymer resistor 4 does not recover to the initial resistance value, or it takes time to recover. However, the heat generation performance decreases.

  Therefore, a liquid-resistant resin with high crystallinity is added to the resin composition 33, and the reactive resin, the conductor, and the liquid-resistant resin that express PTC characteristics are partially chemically bonded. As a result, swelling of the resin composition 33 is suppressed, and the liquid resistance of the polymer resistor 4 is greatly improved.

  As the liquid resistant resin, one of ethylene-vinyl alcohol copolymer, thermoplastic polyester resin, polyamide resin, polypropylene resin, and ionomer can be used alone or in combination.

  These liquid-resistant resins are not only liquid-resistant, but also a decrease in flexibility of the resin composition 33 is suppressed, and the flexibility of the polymer resistor 4 can be maintained.

  When the addition amount of the liquid-resistant resin is 10% by weight or more with respect to the resin composition 33, the liquid resistance to the liquid chemical substance is improved.

  However, when the amount of the liquid-resistant resin increases, the polymer resistor 4 itself tends to be hard, the flexibility is lowered, and the conductor is trapped by the liquid-resistant resin, and the conductive path is cut even if the temperature rises. It becomes difficult to be done, and the PTC characteristic deteriorates.

  Therefore, in order to satisfy the flexibility, PTC characteristics, and liquid resistance of the polymer resistor, the addition amount of the liquid-resistant resin is preferably 10 to 70% by weight, and most preferably 30 to 50% by weight.

  The above-described liquid chemical substance is dropped on the polymer resistor 4 containing no liquid-resistant resin and the polymer resistor 5 containing 50% by weight of the various liquid-resistant resins, and energized for 24 hours after 24 hours. Then, the resistance value before and after the test when left at room temperature for 24 hours increased by 200 to 300 times for the polymer resistor 5 not containing the liquid-resistant resin, whereas the polymer resistor 4 containing the liquid-resistant material was used. Were 1.5 to 3 times, and good results were obtained.

  From this result, by adding a liquid-resistant resin to the polymer resistor 4, the swelling of the resin composition 33 constituting the polymer resistor 4 due to liquid chemical substances such as engine oil, organic solvents, and beverages is suppressed. You can see that Thereby, stability of the resistance value of the polymer resistor 4 is ensured, and high durability and reliability are obtained as the planar heating element 1.

  In addition, as a car seat heater incorporated in an automobile seat, the planar heating element 1 can satisfy a seating feeling and flame retardancy. The seating sensation is satisfactory because there is no squeaking like paper and an elongation characteristic equivalent to that of the seat skin material, that is, a load of 7 kgf or less for an elongation of 5%.

  In addition, the planar heating element 1 having the PTC characteristic can exhibit quick heat and energy saving as compared with the heating element having no PTC characteristic. A heating element having no PTC characteristic requires a temperature controller, and the temperature controller controls the heat generation temperature by controlling energization by ON-OFF control. In particular, in the case of a heating element having a PTC characteristic using a filament heating wire, the heating element temperature at the time of ON is raised to about 80 ° C. in order to avoid a low temperature portion between the filament heating wires. Need to be placed at some distance.

  On the other hand, in the planar heating element 1, the heating element temperature is self-controlled within the range of 40 ° C to 45 ° C. Therefore, it can be arranged close to the vicinity of the skin 10. The sheet heating element 1 has a low heating element temperature and is disposed in the vicinity of the skin 10, so that it is possible to reduce the rapid heating property and heat dissipation loss to the outside. Therefore, energy saving can be realized.

  As described above, in the planar heating element 1 of the present embodiment, the conventional planar heating element has a 5-6 layer structure of a base material, an electrode, a polymer resistor, a heat-fusible resin, and a coating material. On the other hand, the planar heating element 1 has a three-layer structure including an electrically insulating substrate 2, a pair of filament electrodes 3, and a polymer resistor 4.

  With this simple configuration, even when an external force is applied, the restriction of the external force is reduced, and thus flexibility is easily exhibited.

  Therefore, even when subjected to an external force when used as a car seat heater, it is highly flexible and easily deformed, and cracking and peeling of the polymer resistor caused by creases as in the prior art are prevented.

  Further, the planar heating element 1 can be manufactured with a simple configuration of three layers, so that the productivity is excellent and the material cost for configuring the planar heating element 1 is reduced. As a result, it can be produced at low cost.

  Further, since a resin film such as a non-breathable polyester sheet is not used with the polymer resistor 4 interposed therebetween, moisture is likely to be trapped when used for a car seat heater or a handle heater as in a conventional sheet heating element. This solves the problem, and even when used for a long time, a seating feeling and a touch feeling equivalent to those in the initial stage can be obtained, and a comfortable heating effect can be obtained.

  In addition, since the electrodes are composed of filaments, they can be configured simply, unlike the conventional complicated comb electrodes.

  Therefore, the cost of the electrode material can be reduced, and even when an external force is applied when used as a car seat heater, the generation of electrode wrinkles is suppressed, and the electrode can be prevented from being damaged, and has excellent durability. A heating element 1 is obtained.

  The wire electrode 3 is composed of at least one of a metal conductor and a metal braided conductor. These materials are easy to sew to the electric base material insulation 2 and have high productivity.

  Moreover, the selection range of the material and shape of the metal conductor and the metal braided conductor is expanded. Further, since the metal conductor and the metal braided conductor are excellent in flexibility and have high mechanical strength, they can endure for a long period of time even if the planar heating element is repeatedly stretched, bent, or deformed.

  The resistance of the line electrode 3 is preferably as low as possible, and the voltage drop at the line electrode 3 is preferably small.

  The linear electrode 3 has a suitable resistance value at which the voltage drop of the voltage applied to the planar heating element 1 is 1 V or less, and is preferably 1 Ω / m or less in terms of the resistance value.

  Further, if the wire diameter of the filament electrode 3 is large, irregularities are formed on the planar heating element 1 and the seating feeling is impaired. Therefore, the diameter is preferably 1 mm or less, and in order to realize a more comfortable seating feeling, the diameter 0 .5 mm or less is preferable.

  Examples of the material that realizes the resistance value include copper, tin-plated copper, copper-silver alloy single wire, stranded wire, and braided wire. Particularly, in terms of mechanical strength, it is preferable to use copper-silver having high tensile strength.

  The linear electrode 3 has a conductive coating 6 whose main components are a resin composition and a conductor. As the resin composition, similarly to the polymer resistor 5, a modified olefin resin such as ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, ethylene methyl methacrylate copolymer, ethylene methacrylic acid copolymer, It can be used alone or in combination with an ester-based ethylene copolymer such as ethylene butyl acrylate or the above-described reactive resin.

  In addition, as a conductor to impart conductivity, carbon black, graphite, conductive ceramic fibers tin-plated titanium oxide and doped with antimony, potassium titanate-based conductive ceramic whiskers, metal fibers such as copper and aluminum, Metal-plated glass fibers, carbon fibers, carbon nanotubes with a conductive layer formed on the surface, fibrous conductive polymers such as polyaniline, ceramic flakes such as mica flakes with a conductive layer formed on the surface, copper and aluminum Metal flakes such as flaky graphite can be used.

  Heaters used in automotive seating equipment and the like must satisfy the flame retardancy of the US automotive interior material flame retardant standard FMVSS302. Specifically, if any of the following conditions is met, flame retardancy can be achieved. It becomes.

  (1) When the end face of the test product is blown with a gas flame and the gas flame is extinguished after 60 seconds, the test sample itself does not burn even if the polymer resistor 5 is burnt.

  (2) The end face of the test product is blown with a gas flame, and once the test product is lit, the fire is extinguished within 60 seconds and within 2 inches.

  (3) Even if the end face of the test product is blown by a gas flame and the test product is ignited, the flame does not proceed at a speed of 4 inches / minute or more in the region of 1/2 inch thickness from the surface.

  The above flame retardancy can be realized by adding a flame retardant to the polymer resistor 4, the conductive coating 6, and the electrically insulating substrate 2.

  As the flame retardant, a phosphorus flame retardant such as ammonium phosphate or tricresyl phosphate, a nitrogen flame retardant such as melamine, guanidine, guanylurea, or a silicone compound alone or a combination thereof can be used.

  Further, inorganic flame retardants such as magnesium hydroxide and antimony trioxide and halogen flame retardants such as bromine and chlorine can be used.

By containing these flame retardants in the polymer resistor 4, the conductive coating 6, and the electrically insulating substrate 2, the above-described flame retardant conditions are satisfied, and the flame retardant excellent as the planar heating element 1 is achieved. Therefore, it is possible to improve the safety of the planar heating element 1 mounted for heating the seat device for automobiles and its applied products.

  In addition, the flame retardant is particularly preferably a liquid that is liquid at room temperature or has a melting point that melts at a kneading temperature. By using at least one of a phosphorus-based, nitrogen-based, and silicone-based compound, the flexibility of the resin composition 33 is improved. As a result, the polymer resistor 5 can also improve flexibility.

  Thereby, the flexibility which the electrically insulating base material 2 has is not impaired, a flame retardance can be provided, and the mechanical durability and reliability as the planar heating element 1 are ensured.

  The amount of flame retardant added is determined by the overall composition of the conductive coating 6. When the flame retardant is decreased, the flame retardancy is inferior, and the above-described flame retardant conditions are not satisfied.

  From this point, the amount of the flame retardant added may be 5% by weight or more with respect to the composition of the polymer resistor 5. However, when the amount of the flame retardant added is increased, the composition balance between the resin composition 33 and the conductor is deteriorated, the specific resistance of the conductive polymer resistor 5 is increased, and the PTC characteristics are deteriorated. 30% by weight, best is in the range 15-25% by weight.

  Further, by using a flame retardant conductor as the conductor of the conductive coating 6, flame resistance can be imparted to the conductive coating 6. Examples of the flame retardant conductor include metals, metal oxides, metal carbides, metal nitrides, and metal borides.

  Specifically, conductive ceramic fibers tin-plated on titanium oxide and doped with antimony, conductive ceramic whiskers based on potassium titanate, metal fibers such as copper and aluminum, and metal-plated glass fibers with a conductive layer formed on the surface Ceramic flakes such as mica flakes having a conductive layer formed on the surface, metal flakes such as copper and aluminum, and the like can be used.

  In addition, since the filament electrode 3 has a conductive coating, when an external force is applied, the filament electrode is protected even when severe stress such as bending is applied, and the filament electrode is disconnected. Can be prevented.

  In particular, when the planar heating element 1 is used as a heating heat source of an automobile seat device, as shown in FIGS. 3 and 4, durability of the line electrode 3 is required because a strong stress is applied by a human load. Come.

  FIG. 7 shows the results of evaluating the durability of the linear electrode 3 against bending. As shown in the figure, an electrically insulating base material 2 in which the filament electrodes 3 are sewn is installed between the head 11 and the base 12, both ends of the electrically insulating base material 2 are fixed, and the head 11 is moved up and down 180. The endurance was evaluated from the change in the resistance value of the filament electrode 3 by bending.

  In FIG. 6, an increase in the rate of change of the resistance value indicates that the wire electrodes are broken. In the case where the filament electrode is only 19 strands having a diameter of 0.06 mm, the case (B) where the conductive coating 6 is provided on the same strand as (A) was evaluated.

  In the case of only a stranded wire, (A) increases the resistance value at about 2000 times of bending, whereas in the case where conductive coating 6 is provided on the stranded wire (B), there is no change up to about 10000 times. The durability against bending is greatly improved by the conductive coating 6.

Therefore, when the planar heating element 1 is used as a car seat, the filament electrode is protected even when severe stress such as bending due to a human load is applied, and the filament electrode can be prevented from being disconnected. it can.

  As the electrically insulating base material 2, for example, a needle punch type nonwoven fabric made of polyester fiber is used. Besides this, a polyester woven fabric may be used. These electrically insulating base materials 2 impart flexibility to the planar heating element 1 and easily deform even when an external force is applied, thereby improving the seating feeling when used as an automobile seat device.

  In particular, when the filament electrode 3 is attached by sewing, the above nonwoven fabric and woven fabric are optimal in terms of prevention of cracks generated from the needle holes of the electrically insulating base material 2 by sewing and flexibility.

  The filament electrode 3 is attached to the electrically insulating base material 2 by sewing with a sewing machine or the like. According to the structure produced by this method, the linear electrode 3 can be firmly fixed to the electrically insulating substrate 2 and can be deformed following the deformation of the electrically insulating substrate 2, thereby improving the mechanical reliability. .

  Moreover, since the sewing to the electrically insulating base material 2 is performed by the thread 5, the selection range of the electrode material and the shape is expanded.

  Furthermore, unlike the conventional complex comb-shaped electrode, the line electrode 3 can be a simple configuration having at least a straight pair of shapes, so that the material cost is low and the cost can be reduced.

  Moreover, even when an external force is applied when used as a heat source for an automobile seat device, generation of wrinkles on the line electrode 3 is suppressed, and damage to the electrode is prevented.

  Next, an example of a method for manufacturing the planar heating element 1 will be described.

  First, the shape shown by A and B of FIG. 1 with the polyester thread | yarn 4 which used what twisted 19 copper-silver alloy wires with a diameter of 0.05 micrometer for the electrically insulating base material 2 which consists of a nonwoven fabric of a polyester fiber. The filament electrode 3 is formed by sewing with a sewing machine.

  The distance between the electrodes of the pair of filament electrodes 3 at this time is 100 mm. Next, a kneaded material A is prepared from the resin to be reacted that exhibits PTC characteristics, a liquid-resistant resin, and a conductor, and a kneaded material B including a reactive resin and a flame retardant is prepared.

  Then, they are further kneaded and mixed and extruded from a T-die or a hot roll connected to an extrusion apparatus to form a film.

  In this way, the polymer resistor 4 is produced. The kneaded product A and the kneaded product B are kneaded with an apparatus such as a hot roll, a kneader, or a biaxial kneader.

  The thickness of the polymer resistor 4 is not particularly limited, but 20 to 200 μm is appropriate in terms of flexibility, material cost, appropriate resistance value, and strength when a load is applied. 30-100 micrometers is good.

  Next, the polymer resistor 4 molded into a film and extruded is bonded to the surface of the electrically insulating substrate 2 to which the filament electrode 3 prepared in advance is present. The planar heating element 1 is completed as described above.

As described above, the linear electrode 3 and the polymer resistor 4, and the electrically insulating substrate 2 and the polymer resistor 4 are bonded to each other by heat fusion. As a result, the line electrode 3 is disposed in an electrically connected state between the electrically insulating substrate 2 and the polymer resistor 4.

  Since the polymer resistor 4 is a flexible sheet or film, the polymer resistor 5 itself responds to the external force in the same manner as the electrically insulating substrate 2 even if an external force is applied to the planar heating element 1. Since elongation and deformation occur, breakage such as cracks and breaks of the polymer resistor 4 is prevented, and excellent durability is realized.

  Further, by forming the polymer resistor 4 in the form of a sheet or film, the film thickness can be made thicker than the polymer resistor of the printed film, and electrical connection and mechanical joining with the line electrode 3 can be achieved. The reliability will be higher.

  Furthermore, since the polymer resistor 4 continuously extruded can be bonded while being bonded to the electrically insulating substrate 2 to which the filament electrode 3 is attached, it is excellent in productivity and low cost can be realized.

  In addition, it is preferable that the polymer resistor 4 has an elongation equal to or greater than that of the electrically insulating substrate 2. By making the elongation of the polymer resistor 4 equal to or greater than that of the electrically insulating substrate 2, the electrically insulating substrate 2 having a high mechanical strength can regulate elongation and deformation due to external force, and thus is more excellent. Durability and reliability.

  Moreover, the polymer resistor 4 is affixed to the electrical insulating base material 2 to which the linear electrode 3 is previously attached by disposing the polymeric resistor 4 on the electrical insulating base material 2 and the linear electrode 3. A manufacturing method can be adopted.

  According to this manufacturing method, since the polymer resistor 4 immediately after molding is in a high temperature state, it is easily and firmly bonded to the linear electrode 3 and the electrically insulating substrate 2. As a result, electrical connection and mechanical joining can be obtained stably.

  Furthermore, by thermally fusing the polymer resistor 4 to the filament electrode 3, the material of the polymer resistor 4 is transferred around the filament electrode 3, and the filament electrode 3 and the polymer resistor 4 are dotted. Instead of bonding, surface bonding can be used.

  As a result, mechanical joining and electrical connection between the line electrode 3 and the polymer resistor 4 become strong, and an electrically and mechanically stable planar heating element 1 can be obtained.

  The planar heating element 1 configured as described above is preferably used by being arranged on the seat portion 7 and the backrest 8 so that the electrically insulating base material 2 is on the surface side. That is, the cushioning property of the electrically insulating base material 2 makes it impossible to feel the unevenness due to the thickness and hardness of the line electrode 3 on the seating surface, and the seating feeling and the backrest feeling are not impaired.

  In addition, when flame resistance is imparted to the electrically insulating base material 2, it is possible to prevent the spread of fire in combustion by arranging the electrically insulating base material 2 on the surface side, and a highly safe seat is obtained.

  In the planar heating element according to the present invention, the electrodes are protected by a conductive coating, and are durable against strong stress such as bending. Since this planar heating element can be mounted on the surface shape of an appliance having, for example, a continuous curved surface or a combination of flat surfaces, an automobile floor, a handle, and other electric floor heating that requires heating as a heater for heating, etc. Applicable to any apparatus. In addition, since the productivity is excellent and the cost can be reduced, the application range of applied products is expanded.

DESCRIPTION OF SYMBOLS 1 Planar heating element 2 Electrically insulating base material 3 Line electrode 4 Polymer resistor 6 Conductive coating 7 Seat part 8 Backrest

Claims (8)

A flexible electrically insulating substrate, at least one pair of linear electrodes having a conductive coating composed mainly of a resin composition and a conductor, and a principal component consisting of a resin composition and a conductor A polymer resistor, and the polymer resistor is electrically connected to the pair of linear electrodes and mechanically joined to the electrically insulating substrate and the pair of linear electrodes. A planar heating element with a different configuration. The planar heating element according to claim 1, wherein the filament electrode is composed of at least one of a metal conductor and a metal braided conductor. The planar heating element according to claim 1, wherein the conductive coating has flame retardancy that satisfies at least one of the following conditions.
(1) If the end face of the conductive coating is blown with a gas flame and the gas flame is extinguished after 60 seconds, the conductive coating itself does not burn even if the sheet is burnt.
(2) The end face of the conductive coating is blown with a gas flame, and once the conductive coating is ignited, the fire is extinguished within 60 seconds and within 2 inches.
(3) The end face of the conductive coating is blown with a gas flame, and even if the conductive coating is ignited, the flame does not advance at a speed of 4 inches / minute or more in the region of 1/2 inch thickness from the surface. 4. The planar heating element according to claim 3, wherein the flame retardant is liquid at normal temperature or has a melting point that melts at a kneading temperature, and is composed of at least one of a phosphorus-based, nitrogen-based, and silicone-based compound. The planar heating element according to claim 1, wherein the electrically insulating substrate has flame retardancy that satisfies at least one of the following conditions.
(1) When the end face of the electrically insulating substrate is blown with a gas flame and the gas flame is extinguished after 60 seconds, the electrically insulating substrate itself does not burn even if the electrically insulating substrate is burnt.
(2) The end face of the electrically insulating substrate is blown with a gas flame, and the fire is extinguished within 60 seconds and within 2 inches even if the electrically insulating substrate is once ignited.
(3) The end face of the electrically insulating substrate is blown with a gas flame, and even when the electrically insulating substrate is ignited, the flame is at a speed of 4 inches / minute or more in a region of 1/2 inch thickness from the surface. Do not proceed with. The planar heating element according to claim 1, wherein the conductor is made of at least one of a metal, a metal oxide, a metal carbide, a metal nitride, and a metal boride. An automobile seat device equipped with the planar heating element according to any one of claims 1 to 6 as a heating heat source. 8. The vehicle seat apparatus according to claim 7, wherein a sheet heating element is mounted so that the electrically insulating base is on the surface side of the seat and the backrest.