JP2008310967A - Surface heating element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that if an electrode wire is sewed and fixed by a cotton sewing thread and a heat resistant fiber or the like, adhesiveness of the electrode wire and a resistor is inhibited and that there is mechanical instability and electrical instability. <P>SOLUTION: By fixing a filaceous electrode 3 of a surface heating element 1 by a thread 5 of a thermoplastic resin composition, the thermoplastic resin melts by heating at molding, and firmly adheres a PTC resistor composition 4 to the filaceous electrode 3 and the filaceous electrode 3 to electric insulating base material 2, and the filaceous electrode 3 with an electric insulating substrate 2. Accordingly, a superior feeling of use can be obtained when mounted for heating of a seat device of an automobile. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a planar heating element having good structural adhesion and electrical contact and capable of supplying a stable current.

  Conventionally, as a heating part of a planar heating element, a resistor obtained by printing, drying and baking a resistor ink in which a base polymer and a conductive substance are dispersed in a solvent is used.

  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.

  More specifically with reference to FIGS. 5 and 6, the planar heating element 51 includes an electrically insulating base 52, a pair of comb-shaped electrodes 53 and 54, a PTC resistor composition 55, and a covering material. 56.

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

  The PTC resistor composition 55 is formed by printing and drying PTC resistor composition 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 PTC resistor composition 55.

  When a polyester film is used as the base material 52 and the covering material 56, a heat-fusible resin 57 such as polyethylene is bonded to the covering material 56 in advance.

  Then, by applying pressure while applying heat, the base material 52 and the covering material 56 are joined via the heat-fusible resin 57.

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. Therefore, the PTC resistor composition 55 having PTC characteristics can impart a self-temperature adjusting function to the planar heating element 51 (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 56-13689

  Thus, in the conventional sheet heating element 51, a rigid material such as a polyester film is used as the base material 52. In addition, it has a five-layer structure including a base material 52, comb-shaped electrodes 53 and 54 and a PTC resistor composition 55 printed thereon, and a covering material 56 having an adhesive layer disposed thereon. .

  Therefore, depending on the material of the base material 52 and the covering material 56 and the thickness thereof, there are not only practical disadvantages of lacking flexibility, but also economic disadvantages of complicated processes and high mass production costs.

  Therefore, instead of printing the electrodes, a configuration in which a metal electrode wire is fixed to a substrate in advance and the PTC resistor composition is disposed thereon can be considered. According to this, it can comprise by a 2 layer structure. The electrode wires are generally sewn using cotton sewing threads, particularly aramid fibers to give heat resistance and strength.

  However, in this case, although the configuration is simplified, the sewing thread inhibits the adhesion between the electrode line and the resistor, and further, the sewing thread inhibits the electrical contact between the electrode line and the resistor. There was a problem.

  The present invention solves such a conventional problem, and realizes a planar heating element having improved adhesion between a PTC resistor composition and an electrode wire, and between the electrode wire and an electrically insulating substrate. .

  In order to solve the conventional problems, a planar heating element of the present invention includes a PTC resistor composition, a line electrode, and an electrically insulating substrate, and the line electrode is a thermoplastic resin composition. The PTC resistor composition is disposed on the sewing thread.

  As a result, the thermoplastic resin is melted by heating at the time of molding, and is cooled and solidified, whereby the PTC resistor composition and the electrode, and the electrode and the electrically insulating substrate are bonded to each other. An excellent sheet heating element is realized.

  The planar heating element of the present invention improves the adhesion between the PTC resistor composition and the electrode, and the electrode and the electrically insulating substrate by using a thermoplastic resin as a sewing thread for sewing the linear electrode. It is possible to manufacture a sheet heating element having excellent performance stability by a simple production process.

  A first invention comprises a PTC resistor composition, a filament electrode, and an electrically insulating substrate, wherein the filament electrode is fixed by a thread of a thermoplastic resin composition, and the PTC resistance is formed on the thread. The body composition is arranged.

  Since the thermoplastic resin is melted by heating and solidified by cooling, the PTC resistor composition and the electrode, and the electrode and the electrically insulating substrate can be bonded. Therefore, by using the thermoplastic resin composition thread, it is possible to realize a highly stable planar heating element in which the electrode is fixed to the substrate and the PTC resistor composition is also fixed.

  In a second invention, the thermoplastic resin of the first invention is a low melting point resin having a melting point of 80 to 150 ° C.

  When the melting point is high, the moldability is deteriorated. On the other hand, when the melting point is too low, the stability is lowered due to heat generation of the resistor.

  Assuming a heater for heating in a car seat device, the temperature of the resistor does not exceed 80 ° C., and the melting point is set to 80 to 150 ° C. in order to improve the workability. It is possible to realize a planar heating element provided with.

In the third invention, the thermoplastic resin of the first invention is an ionomer resin, and the PTC resistor composition contains an ethylene methacrylic acid copolymer. Since the ionomer resin is also an ethylene methacrylic acid copolymer, the adhesion between the sewing thread and the PTC resistor composition is further improved.

  According to a fourth aspect of the present invention, the filament electrode of the first aspect of the present invention is composed of a zinc-plated wire, and the thermoplastic resin is composed of an ionomer resin having a zinc ion crosslinking structure.

  As a result, the carboxylic acid group of the ionomer resin can form a crosslinked structure with the plated zinc and the adhesion is further improved.

  In a fifth aspect of the present invention, a conductor is contained in the resin composition of the first aspect. Thereby, the electrical connectivity between the electrode and the PTC resistor composition can be improved.

  In the sixth invention, the resin composition of the fifth invention does not have PTC characteristics. When it has PTC characteristics, the resistance of the sewing thread increases as the temperature rises, and heat generation at the electrode of the planar heating element becomes obvious, but this can be prevented by having no PTC characteristics. .

  In a seventh invention, the electrically insulating substrate of the first invention is composed of at least one of a woven fabric and a non-woven fabric, imparts flexibility to the planar heating element, and easily deforms even when an external force is applied. It is what I did.

  In an eighth aspect of the present invention, the planar heating element according to any one of the first to seventh aspects is mounted for heating a seat device of an automobile, and the seating feeling is improved.

  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. In addition, a configuration unique to each embodiment can be combined as appropriate.

(Embodiment 1)
1 and 2, the planar heating element 1 is basically composed of an electrically insulating base material 2, a linear electrode 3, a PTC resistor composition 4, and a sewing thread 5.

  The filament electrode 3 is disposed on the electrically insulating substrate 2 and is partially sewn with a sewing thread 5.

  The PTC resistor composition 4 is formed on the electrically insulating base material 2 on which the filament electrodes 3 are arranged by extruding it into a film by, for example, a T-die extrusion method. Thereby, the PTC resistor composition 4 is heat-sealed to the filament electrode 3 and the electrically insulating substrate 2.

  A lead wire for supplying power from the power source to the wire electrode 3 is not shown.

  3 and 4 show an automobile seat device to which the planar heating element 1 is attached. The electrically insulating base material 2 is mounted on a seat 6 as a heater for heating or a backrest 7 provided so as to stand up from the seat 6. The planar heating element 1 is attached so that is located on the surface side.

  Further, the seat 6 and the backrest 7 are provided with a seat base material 8 and an outer skin 9. The seat base material 8 such as a urethane pad is deformed when a load is applied by a human body sitting on the seat base 8, and the shape is restored when the load is no longer applied.

The skin 9 covers the seat base 8. That is, the planar heating element 1 is attached to the seat base material 8 with the PTC resistor composition 4 side and the skin 9 with the electrically insulating base material 2 side. In addition, in order to correspond to the hanging part (not shown) of the seat part 6 or the backrest 7, the extension part (not shown) of the electrically insulating base material 2 for hanging in a center part or a peripheral part is provided. There is also.

  Thus, the thin planar heating element 1 is disposed along the seat base 8 and the skin 9 that can be deformed. Therefore, the planar heating element 1 must be similarly deformed corresponding to the deformation of the seat 6 and the backrest 7. Therefore, it is necessary to design various heat generation patterns and to change the arrangement shape of the line electrodes 3 for that purpose. The details are omitted here.

  A pair of wide linear electrodes 3 arranged so as to face each other are arranged along the outer side in the longitudinal direction of the planar heating element 1.

  By supplying power from the filament electrode 3 to the PTC resistor composition 4 disposed so as to overlap the filament electrode 3, a current flows through the PTC resistor composition 4 to generate heat.

  The PTC resistor composition 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 PTC resistor composition 4 gives the planar heating element 1 a function that is highly safe and does not require temperature control.

  As described above, the planar heating element 1 has a two-layer structure of the electrically insulating base material 2 and the PTC resistor composition 4 to which a pair of filament electrodes 3 are attached.

  With this configuration, the planar heating element 1 can be manufactured with a simple configuration, 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.

  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 are easily deformed even when an external force is applied to improve the seating feeling when used for heating a seat device of an automobile.

  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 sewing thread 5, the selection range of the electrode material and the shape is expanded. Furthermore, unlike the conventional complicated comb-shaped electrode, the filament 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.

  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.

  Further, the selection range of the material and shape of the metal conductor and the metal braided conductor is widened.

  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.

  In addition, since the electrode is composed of a filament, unlike the conventional complicated comb-shaped electrode, it can have a simple structure, and the cost of the electrode material can be reduced.

  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 for realizing this resistance value include copper, tin-plated copper, copper-silver alloy, single wire such as galvanized metal wire, stranded wire, and braided wire.

  As the resin of the PTC resistor composition 4, when the heat generation temperature is relatively low as 40 to 50 ° C. like a car seat heater, a modified olefin resin which is a low melting point resin such as an ethylene vinyl acetate copolymer is used. 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 sewing thread 5 is formed of a thermoplastic resin having a low melting point, and for example, polyethylene, polypropylene, vinyl acetate, ethylene vinyl acetate copolymer, ethylene methacrylic acid copolymer, ionomer resin, or the like can be used.

  Further, in order to impart conductivity to the sewing thread 5, a conductive material such as carbon black, graphite, carbon nanotube, or carbon fiber can be added.

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

  First, an electrically insulative base material 2 made of polyester fiber non-woven fabric is formed by twisting 10 galvanized metal wires having a diameter of 0.1 μm into a shape shown in FIG. A strip electrode 3 is formed.

  Here, the sewing thread 4 is a resin composition formed by adding 20% by weight of carbon nanotubes to a zinc cross-linked ionomer resin. The distance between the electrodes of the pair of filament electrodes 3 at this time is 100 mm.

  Next, as a composition exhibiting PTC characteristics, an ethylene methacrylic acid copolymer having a melting point of 90 to 100 ° C. and carbon black are kneaded and mixed to prepare a resistor composition. And a resistor composition is extruded from the T die connected with the extrusion apparatus, and is shape | molded in a film form.

  In this way, the PTC resistor composition 4 is produced. The kneading and mixing of the resistor composition is performed by an apparatus such as a hot roll, a kneader, or a biaxial kneader.

  The thickness of the PTC resistor composition 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, and is desirable. Is preferably 30 to 100 μm.

Next, the PTC resistor composition 4 molded into a film shape and extruded from the T-die is present in the presence of the filament electrode 3 of the electrically insulating substrate 2 to which the filament electrode 3 prepared in advance is attached by the sewing thread 4. The surface to be bonded is bonded with heat by a laminator.

  At this time, the sewing thread 4 is melted by heating with a laminator, and the electrically insulating substrate 2 and the filament electrode 3, the PTC resistor composition 4 and the filament electrode 3 are bonded. The planar heating element 1 is completed as described above.

  In the sheet heating element 1 configured as described above, the sewing thread 5 and the zinc-plated metal filament electrode 3 containing a zinc cross-linked ionomer resin as a component have high adhesion via zinc ions. The PTC resistor composition 4 comprising the same component as the ionomer resin containing an ethylene methacrylic acid copolymer as a component has high adhesion.

  Further, the sewing thread 5 to which carbon nanotubes are added has a volume resistivity of 1 Ω · cm and high conductivity and does not have PTC characteristics. Thereby, inhibition of electrical connection between the filament electrode 3 and the PTC resistor composition 4 can be suppressed, and heat generation in the sewing thread 5 can be prevented.

  The planar heating element according to the present invention has a simple configuration, excellent stability of PTC characteristics, and mechanical stability against deformation due to external force. 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.

The top view which shows the planar heating element in Embodiment 1 of this invention XY sectional view of FIG. Side view when used in a car seat device Front view Plan view of a conventional planar heating element XY sectional view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Planar heating element 2 Electrically insulating base material 3 Line electrode 4 PTC resistor composition 5 Sewing thread

Claims (8)

A PTC resistor composition, a linear electrode, and an electrically insulating base material, wherein the linear electrode is fixed by a sewing thread of a resin composition containing a thermoplastic resin, and the PTC resistor composition is formed on the sewing thread. A planar heating element with objects. The planar heating element according to claim 1, wherein the thermoplastic resin is a low melting point resin having a melting point of 80 to 150 ° C. The planar heating element according to claim 1, wherein the thermoplastic resin is an ionomer resin, and the PTC resistor composition contains an ethylene methacrylic acid copolymer. The planar heating element according to claim 1, wherein the filament electrode is made of a zinc-plated wire, and the thermoplastic resin is made of an ionomer resin having a crosslinked structure of zinc ions. The planar heating element according to claim 1, wherein a conductor is contained in the resin composition. The planar heating element according to claim 5, wherein the resin composition does not have PTC characteristics. The planar heating element according to claim 1, wherein the electrically insulating substrate is composed of at least one of a woven fabric and a nonwoven fabric. A seat device for an automobile equipped with the planar heating element according to any one of claims 1 to 7.

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