JP2011003330A - Planar heating element and seat using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planar heating element having excelling durability, even if it is deformed.SOLUTION: The planar heating element includes an electrical insulating base material 2 having flexibility; a polymer resistor 4 which is mounted to the electrical insulating base material and the main component of which is composed of a resin composition and a conductor; at least a pair of filament electrodes 3 electrically connected to the polymer resistor 4; and a flexible electrical insulating film 7 bonded to the polymer resistor 4, through an adhesive layer the main component of which includes a thermoplastic elastomer and made of a resin having an elastic modulus smaller than that of a general purpose resin.

Description

  The present invention relates to a planar heating element having flexibility and high reliability that can be mounted on an instrument having an arbitrary surface shape, and a seat using the planar heating element.

  Conventionally, in this type of planar heating element, a heating element is used that is manufactured by printing, drying, and firing a resistor ink in which a base polymer and a conductive material are dispersed in a solvent. (For example, refer to Patent Document 1, Patent Document 2, and Patent Document 3).

  Carbon black, metal powder, graphite, or the like is used as the conductive substance, and crystalline resin is used as the base polymer. With such a material, the heat generating portion exhibits PTC characteristics.

  Specifically, as shown in FIGS. 8 and 9, a pair of comb-shaped electrodes 102 and 103 and a polymer resistor 104 having PTC characteristics are disposed on an electrically insulating base material 101, and they are covered with a covering material. The sheet heating element 106 was covered with 105.

  The base material 101 is made of a resin such as a polyester film, and comb-shaped electrodes 102 and 103 are formed on the base material 101 by printing and drying a conductive paste such as a silver paste.

  The polymer resistor 104 is formed by printing and drying polymer resistor ink at a position where power is supplied by the comb-shaped electrodes 102 and 103.

  The covering material 105 made of the same material as the base material 101 protects the comb-shaped electrodes 102 and 103 and the polymer resistor 104.

  When a polyester film is used as the base material 101 and the covering material 105, a heat-fusible resin 107 such as a modified polyethylene is bonded to the covering material 105 in advance. And it pressurizes, giving heat.

  By doing in this way, the base material 101 and the covering material 105 are joined via the heat-fusible resin 107.

  The covering material 105 and the heat-fusible resin 107 isolate the comb-shaped electrodes 102 and 103 and the polymer resistor 104 from the outside. Therefore, the sheet heating element 106 is provided with long-term reliability.

  FIG. 10 shows a heating and pressurizing apparatus for laminating the covering material 105, and a laminator 110 composed of two heating rolls 108 and 109 is generally used.

  That is, the base material 101 in which the comb-shaped electrodes 102 and 103 and the polymer resistor 104 are formed in advance and the coating material 105 in which the heat-fusible resin 107 is bonded in advance are supplied, and these are heated by the heating rolls 108 and 109. Heat and pressurize. In this way, the planar heating element 106 is produced.

  The PTC characteristic means a resistance temperature characteristic in which the resistance value increases with a temperature rise, and when the temperature reaches a certain temperature, the resistance value rapidly increases. Therefore, the planar heating element 106 exhibits a self-temperature adjusting function. (For example, refer to Patent Document 1).

  Also, an ink was prepared by dispersing a PTC composition comprising amorphous polymer, crystalline polymer particles, conductive carbon black, graphite and an inorganic filler in an organic solvent, and then printed on a resin film provided with electrodes. A planar heating element is also proposed in which a polymer resistor is prepared, 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).

  Furthermore, as shown in FIG. 11, the electrodes 113 and 114 and the polymer resistor 115 are sequentially laminated on the flexible substrate 112 by a printing method, and the flexible coating layer 116 is further covered. A heating element 117 can also be seen.

  The flexible base material 112 has a function of impregnating a liquid such as gas barrier property and waterproof property, polymer resistor ink, and the like. A melt film is bonded to form a planar heating element 117.

  On the other hand, the flexible coating layer 116 has gas barrier properties and waterproof properties, and covers the electrodes 113 and 114 and the polymer resistor 115 as a whole. The polyester nonwoven fabric and the surface of the polyester nonwoven fabric are hot such as polyester. This is a structure in which a melt film is bonded, and is bonded to the flexible substrate 112.

  Therefore, the planar heating element 117 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

  For the former sheet heating element 106 in the prior art, a rigid material such as a polyester film is used as the substrate 101. A covering material 105 having printed comb-shaped electrodes 102 and 103, a polymer resistor 104, and an adhesive layer 107 exists on the substrate 101, and has a so-called five-layer structure.

  Therefore, depending on the material and the thickness of the base material 101 and the covering material 105, there is a problem that lacks flexibility. That is, when the sheet heating element 106 is used as a heater for heating an automobile seat, the seating feeling is impaired, and when it is used as a handle heater, the feeling of touch 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 106 is deformed.

  Depending on the shape of the deformation, the closer to the end of the sheet heating element 106, the larger the amount of deformation, causing creases or the like in part of the surface.

  In addition, cracks or the like may occur in the comb-shaped electrodes 102 and 103 and the polymer resistor 104 at the crease portion, and there is a concern that durability may be reduced.

  In addition, since a base material 101 such as a non-breathable polyester sheet or a covering material 105 is used, moisture is likely to be trapped when used for an automobile seat or a handle heater, and a feeling of seating or touch when used for a long time. Was damaged.

  On the other hand, since the electrodes 113 and 114, the polymer resistor 115, the base material 112, and the covering layer 116 have flexibility, the latter sheet heating element 117 can be used for an automobile seat or a handle heater. Although the seating feeling and the touch feeling are good, the planar heating element 117 has a multilayer structure, so that the productivity is poor and the cost is increased as a result.

  In addition, the flexible coating layer 116 covering the electrodes 113 and 114 and the polymer resistor 115 as a whole has gas barrier properties and waterproof properties, but is resistant to chemical substances such as engine oil, organic solvents, and beverages (hereinafter referred to as the following). And the resistance of the polymer resistor 115 changes depending on the chemical substance, and the resistance value changes, and a stable heat generation performance cannot be obtained.

  The present invention solves the above-described conventional problems, and provides a low-cost planar heating element that easily exhibits flexibility even when an external force is applied, increases the feeling of use, and is excellent in durability and reliability. For the purpose.

  In order to solve the above-mentioned conventional problems, the planar heating element of the present invention includes an electrically insulating base material having flexibility, and a resin composition and an electrical conductor comprising main components attached to the electrically insulating base material. A polymer resistor comprising: a polymer resistor; at least a pair of linear electrodes electrically connected to the polymer resistor; and a main component bonded to the polymer resistor via an adhesive layer made of a thermoplastic elastomer. In addition, a flexible electrical insulating film made of a resin having a smaller elastic modulus than that of a general-purpose resin is used.

  The planar heating element of the present invention is excellent in flexibility, anti-deformation stress from external force, and can exhibit high resistance to liquid chemicals such as oil, and has excellent durability and reliability. In addition, it is possible to realize a feeling of use and a touch feeling and to provide a low-cost planar heating element.

The top view which shows the planar heating element in Embodiment 1 of this invention XY sectional view of FIG. 1 is a perspective side view of an automobile seat to which a planar heating element according to Embodiment 1 is attached. Perspective front view of the same seat Explanatory drawing explaining the PTC expression mechanism at the time of using a granular conductor Characteristic diagram showing the action and effect of the coplanar heating element Schematic diagram of characteristic evaluation device for coplanar heating elements A perspective plan view of a conventional planar heating element XY sectional view of FIG. Sectional drawing which shows schematic structure of an example 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, a polymer resistor comprising a resin composition and a conductor as main components attached to the electrically insulating substrate, and the polymer resistor. And at least one pair of linear electrodes that are electrically connected to each other, and an electrical insulating film that is bonded to the resistor via an adhesive layer whose main component is a thermoplastic elastomer, Since the conventional planar heating element can be made into a four-layer structure from a five- to six-layer structure, 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, since the electrically insulating film is made of a resin having a smaller elastic modulus than that of a general-purpose resin, it has a high flexibility, maintains a good seating feeling when used as a car seat heater, and the resin films rub against each other. It is possible to prevent the sound from being emitted.

  In addition, the planar heating element can be manufactured with a simple structure of four layers, so that it is excellent in productivity, and as a result, it can be produced at low cost.

  Furthermore, since the electrode is composed of a filament, it can be made a simple structure 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 as a car seat heater, the generation of electrode wrinkles is suppressed, and the electrode can be prevented from being damaged.

  In addition, by providing an electrically insulating film, it is possible to suppress swelling and deterioration of the resin that occurs when liquid chemical substances such as engine oil, organic solvents, and beverages come into contact with the resin constituting the polymer resistor. it can. As a result, the stability of the resistance value of the polymer resistor is ensured, and high durability and reliability are obtained as a planar heating element.

  In the second invention, in particular, the filament electrode of the first invention comprises a core wire composed of at least one of a metal conductor and a metal braided conductor, and a resin composition and a conductor as main components outside the core wire. By adopting a configuration having a conductive coating, even if an external force is applied, the bending or pressure of the core wire is relieved by the conductive coating, so that the electrode can be prevented from being damaged and an electrode having excellent durability can be obtained.

In particular, the third aspect of the present invention maintains a good seating feeling when used as a car seat heater by setting the elastic modulus of the flexible electrically insulating film of the first aspect of the invention to 500 MPa or less, and the resin films are It is possible to prevent the noise from being rubbed.
According to a fourth aspect of the present invention, there is provided a planar heating element, in particular, by configuring the flexible electrical insulating film of the planar heating element of any one of the first or third inventions with a polymer alloy containing a plant-derived component. Is no longer necessary, and the environmental load can be reduced when it is discarded.

  In the fifth invention, in particular, when the adhesive layer of the first invention blows the end face of the electric insulating film with a gas flame and extinguishes the gas flame after 60 seconds, the electric insulating film is burnt. However, the electrical insulating film itself does not burn, (2) the end face of the electrical insulating film is blown by a gas flame, and once the electrical insulating film is ignited, it is extinguished within 60 seconds and within 2 inches. 3) The end face of the electrical insulating film is blown by a gas flame, and even if the electrical insulating film 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. By further including a flame retardant that imparts flame retardancy that satisfies at least one of the conditions, the flame retardancy of the planar heating element can be improved, and the safety of heaters and applied products can be improved.

  In particular, the sixth invention has a melting point that melts the flame retardant of the fifth invention at room temperature or melts at the kneading temperature, and uses at least one of phosphorus-based, nitrogen-based, and silicone-based compounds. Thus, flame resistance can be imparted without impairing the flexibility of the electrically insulating base material or polymer resistor, and the safety of the planar heating element and its applied products can be improved. The mechanical durability and reliability as a heating element are ensured.

According to a seventh invention, the planar heating element according to any one of the first to seventh inventions is mounted as a heat source for heating a seat. Specifically, as in the eighth invention, a seat is provided. Adopting a configuration in which the electrically insulating substrate is arranged on the surface side on at least one of the part and the backrest, the heating surface is brought into direct contact with the seating surface so that the temperature of the seating surface can be quickly raised and bonded When flame retardancy is imparted to the layer, the spread of fire during combustion can be prevented, and a highly safe seat can be obtained.

  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)
1 and 2, the planar heating element 1 includes an electrically insulating substrate 2, first and second linear electrodes 3 a and 3 b, and a polymer resistor 4. The linear electrodes 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 bilaterally symmetric and are partially sewn with a thread, on the outer periphery of the core wire 5 made of a metal conductor or a metal braided conductor. It has a conductive coating 6 composed mainly of a resin composition and a conductor.

  The polymer resistor 4 is formed on the electrically insulating substrate 2 on which the filament electrode 3 is disposed by extruding it into a film by, for example, a T-die extrusion method.

  The electrically insulating film 7 is provided via an adhesive layer 8 made of a thermoplastic elastomer as a main component so as to cover the polymer resistor 4. For example, an adhesive layer whose main component is made of a thermoplastic elastomer by a T-die extrusion method. Extruded 8 into a film shape and pasted together and formed into a sheet shape is bonded to the filament electrode 3 and the electrically insulating substrate 2 by heat fusion.

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

  In addition, the lead wire for supplying the electric power from a power supply to the line electrodes 3a and 3b is not illustrated.

  Further, the punching of the central portion is not limited to this place, and may be provided at other places depending on the material and shape of the skin of the seat, for example. In this case, the wiring pattern of the line electrode 3 is changed.

  3 and 4 show a seat of an automobile to which the above-described planar heating element 1 is attached.

  The planar heating element 1 is used by being attached to a seat 9 or a backrest 10 which is a seat of an automobile as a heater for heating. A seat base 11 and a skin 12 are used for the seat 9 and the backrest 10.

  The seat base 11 such as a urethane pad is deformed when a load is applied by a human body seated on the seat, and the shape is restored when the load is no longer applied.

  The skin 12 covers the seat base 11. That is, the planar heating element 1 is attached to the seat base 11 with the electrically insulating base 2 side positioned on the seat base 11 and the electrically insulating film 7 side positioned on the skin 13.

  In addition, in order to correspond to the hanging part (not shown) of the seat part 9 and the backrest 10, 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 11 and the skin 12 which can be deformed. Therefore, the planar heating element 1 must be similarly deformed corresponding to the deformation of the seat 9 and the backrest 10. 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 polymer resistor 4 disposed so as to overlap the filament electrode 3, a current flows 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.

  FIGS. 5A and 5B are diagrams for explaining the PTC expression mechanism. FIGS. 5A and 5B show the case where a granular conductor 13 such as carbon black is used, and FIGS. The case where the body 14 is used is shown. The states where the temperature has increased from the states (a) and (c) are (b) and (d), respectively.

  In the polymer resistor 4 using the granular conductor 13 such as carbon black as the conductor, the granular conductor 13 has an aggregate structure of primary particles as shown in FIG. Thus, a conductive path in a state of point contact between the grains is formed.

  When a current is applied between the linear electrodes 3a and 3b, the polymer resistor 4 generates heat due to the conductive path of the granular conductor 13 as shown in (b), and the specific volume of the resin composition 15 changes, resulting in sensitivity. In this case, the conductive path is disconnected.

  In this way, a positive resistance temperature characteristic having an abrupt increase in resistance value is manifested.

  On the other hand, the polymer resistor 4 using the fibrous conductor 14 as the conductor does not have an aggregate structure of primary particles such as carbon black as shown in FIG. Conductive paths are formed in a state of overlapping in the direction.

  Also in this structure, when a current is applied between the linear electrodes 3a and 3b, the polymer resistor 4 generates heat by the conductive path of the fibrous conductor 14, and the specific volume of the resin composition 15 changes, so that (d The conductive path is cut sensitively as shown in FIG. 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-mentioned carbon black can be cited as long as the granular conductor 13 is used, and the conductive ceramic fiber tin-plated with titanium oxide and doped with antimony is used as the fibrous conductor 14, potassium titanate. Examples thereof include 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 14. 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 15 of the polymer resistor 4 includes a modified polyethylene having a carboxyl group and a reacted resin as a reacted resin that expresses PTC in order to suppress a change with time of the PTC characteristic and reproduce a stable PTC characteristic. What mixed the modified polyethylene which has an epoxy group as a reactive resin to react is good.

  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 enhanced as compared with the case of the reactive resin alone, and as a result, the temperature at which the conductive path of the conductor is formed and cut in the resin composition 15 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 constituting the functional group 15 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 15 has a structure crosslinked through at least one of oxygen and nitrogen.

  When the resin composition 15 includes a reactive resin and a reactive resin that exhibits PTC characteristics, the conductor is captured by the adhesive force and bonding force of the reactive resin, and the reactive resin and the reactive resin Due to this bonding force, the conductive path by the fibrous conductor 14 is stabilized.

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

  The reactive resin and the reactive resin of the resin composition 15 described above can be used either individually 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 15, 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, the planar heating element 1 can satisfy a seating feeling as a heater incorporated in an automobile seat.

  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 of the present embodiment, 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 12.

  The planar heating element 1 has a low heating element temperature and is disposed in the vicinity of the skin 12, so that it can 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. In contrast to this, it has a four-layer structure of an electrically insulating base material 2, a polymer resistor 4, a pair of linear electrodes 3, and an electrically insulating film 7.

  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 an external force is applied when used as a heater for an automobile seat, it is highly flexible and easily deforms, and cracking and peeling of the polymer resistor caused by creases as in the conventional case is prevented.

  In addition, since the planar heating element 1 can be manufactured with a simple configuration of four layers, the planar heating element 1 is excellent in productivity and the material cost for configuring the planar heating element 1 is reduced. As a result, it can be produced at low cost.

  In addition, since the electrode 3 is composed of a filament, it can be configured simply, unlike a conventional complicated comb electrode.

  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.

  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 substrates 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 a heater for an automobile seat.

  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.

  In addition, since the electrical insulating film 7 is provided on the skin 12 side, even if engine oil, organic solvent, beverage or the like is accidentally spilled on the seat, the liquid chemical substance and the resin constituting the polymer resistor Swelling and deterioration of the resin that occurs when contacted can be suppressed.

  As a result, the stability of the resistance value of the polymer resistor is ensured, and high durability and reliability are obtained as a planar heating element.

  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-described liquid chemical substance comes into contact with the polymer resistor 4, the resin composition easily swells and the specific volume changes, and the conductive path of the conductor is cut and the resistance value tends to increase.

  This phenomenon is similar to the change in specific volume due to heat (PTC characteristics). However, when the resin composition of the polymer resistor 4 swells with a liquid chemical substance, it does not recover to the initial resistance value, or it takes time to recover, and the heat generation performance decreases.

  The electrically insulating film 7 is provided to prevent this. By disposing the planar heating element 1 so that the direction in which the liquid chemical substance permeates is on the side of the electrically insulating substrate 2, the electrically insulating film 7 attached to the electrically insulating substrate 2 is liquid. As a result, the 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.

  The thickness of the electrical insulating film 7 is preferably thin from the viewpoint of flexibility of the planar heating element 1, but is used in the range of 5 to 100 μm from the viewpoint of securing liquid resistance performance.

  Furthermore, 10-50 micrometers is preferable when productivity and cost are considered.

  The above-described liquid chemical substance is dropped onto the planar heating element 1 provided with the electrical insulating film 7 and the planar heating element without the electrical insulating film, and energized 24 hours later, and then at room temperature for 24 hours. The resistance value before and after the test when left untreated increased by 200 to 300 times for the sheet heating element without the electric insulating film 7, whereas the sheet heating element 1 provided with the electric insulating film 7 showed any liquid. Also in the chemical substances, the increase was 1.3 to 2 times, and good results were obtained.

  From this result, it can be seen that the provision of the electrically insulating film 7 suppresses the swelling of the resin composition constituting the polymer resistor 4 by liquid chemical substances such as engine oil, organic solvents, and beverages.

  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.

  As the material of the electrical insulating film 7, ethylene-vinyl alcohol copolymer, thermoplastic polyester resin, polyamide resin, polypropylene resin, and ionomer can be used alone or in combination. These general-purpose resins have an elastic modulus. A thin film of 5 to 20 μm is preferable in order to maintain a high seating feeling as high as 1000 MPa or more.

  However, even if it is as thin as this, the noise generated when the resin films rub against each other cannot be completely suppressed.

  Moreover, if the resin film becomes too thin, handling becomes difficult.

  The seating feeling and the prevention of sound can be prevented by applying a resin having a smaller elastic modulus than the general-purpose resin as the electrical insulating film 7.

  If the elastic modulus is about 500 MPa or less, it is possible to satisfy the feeling of sitting and the prevention of sounding, and soft PVC or polyalloy resin film can be used as a material for realizing this.

  In particular, a nanoalloy film manufactured by Toray Industries, Inc. is suitable as a polyalloy resin film. The nanoalloy film had a small elastic modulus of 100 to 200 MPa, and the seating feeling was good and no noise was observed even when the film thickness was 100 μm.

  The planar heating element 1 has a laminated integrated structure of the electrical insulating base material 2, the linear electrode 3, the polymer resistor 4, the adhesive layer 8, and the electrical insulating film 7, and the planar heating element 1 is no longer necessary. In that case, it cannot be disassembled and will be discarded.

  In this respect, soft PVC is difficult to use. The nanoalloy film is a polyester polymer alloy containing a plant-derived component, and can reduce the environmental load at the time of disposal.

  The heater used for the automobile seat needs to satisfy the flame retardancy of the American automobile interior material flame retardant standard FMVSS302. Specifically, if any of the following conditions is satisfied, the flame retardance can be realized. .

  (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 4 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 is desirably imparted to the electrically insulating substrate 2, the polymer resistor 4, the conductive coating 7, and the adhesive layer 8, which can be realized by containing a flame retardant.

  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 7, 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, the safety of the planar heating element 1 such as a heater for an automobile seat and its applied products can be improved.

  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 4 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 7. 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 14 and the conductor is deteriorated, the specific resistance of the conductive polymer resistor 4 is increased, and the PTC characteristics are deteriorated. 30% by weight, best is in the range 15-25% by weight.

  In addition, since the electrode 3 is composed of a filament, it can be configured simply, unlike a conventional complicated comb electrode. Accordingly, the cost of the electrode material can be reduced, and even when an external force is applied when used as a heater for an automobile seat, generation of wrinkles of the electrode 3 is suppressed, and the damage can be prevented, and the durability is excellent. A flat sheet 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. 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.

  It is preferable that the resistance of the line electrode 3 is as low as possible, and the voltage drop at the line electrode 3 is 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.

  Moreover, since the unevenness | corrugation will be formed in the planar heat generating body 1 and the seating feeling will be impaired when the wire diameter of the filament electrode 3 is large, diameter 1mm or less is preferable, and also diameter in order to implement | achieve a more comfortable seating feeling. 0.5 mm or less is good.

  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 filament 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 4, 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 made of polyaniline, etc., 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.

  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 with a thread, 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.

  Further, even when an external force is applied when used as a heater for a car seat, the generation of wrinkles on the linear electrode 3 is suppressed, and the electrode is prevented from being damaged.

  In addition, by providing the wire electrode 3 with a conductive coating, when an external force is applied, the wire electrode 3 is protected even when severe stress such as bending is applied, and disconnection is prevented. be able to.

  Furthermore, since the electrically insulating film 7 is provided so as to cover the filament electrode 3 and the polymer resistor 4, the protective effect of the filament electrode 3 and the polymer resistor 4 can be enhanced.

  In particular, as shown in FIGS. 3 and 4, when the planar heating element 1 is used in an automobile seat, a strong stress due to a human load is applied, so that the durability of the linear electrode 3 is required.

  FIG. 6 shows the results of evaluating the durability of the linear electrode 3 against bending. As shown in FIG. 7, the electrically insulating base material 2 in which the filament electrode 3 is sewn is installed between the head 16 and the base 17, both ends of the electrically insulating base material 2 are fixed, and the head 16 is moved up and down. The durability was evaluated from a change in the resistance value of the filament electrode 3 by bending 180 °.

  In FIG. 6, an increase in the rate of change in resistance value indicates that the wire electrode is being disconnected. The wire electrode was evaluated for the case of only 19 strands having a diameter of 0.06 mm (A) and the case where the conductive coating 6 was provided on the strand (B). In the case of only the stranded wire (A), the resistance value is increased at about 2000 times of bending, whereas in the case where the conductive coating 6 is provided on the stranded wire (B), there is no change up to about 10,000 times, The durability against bending is greatly improved by the conductive coating 6.

  Furthermore, in the case of (C) in which an electrically insulating film 7 is provided on the polymer insulating material 4 via the adhesive layer 8 on the electrically insulating substrate 2, the linear electrode 3 provided with the conductive coating 6, and the polymer resistor 4, 30000 There is no change until more times, and the durability against bending is further improved.

  Here, a nanoalloy film manufactured by Toray Industries, Inc. having a thickness of 50 μm was used as the electrical insulating film 7. As shown in FIG. 5, when the planar heating element 1 is used as a car seat, the wire electrode 3 is protected by the electrically insulating film 7 even when severe stress such as bending due to human load is applied. In addition, disconnection of the filament electrode 3 can be prevented.

  Furthermore, electrical insulation can be imparted to the surface of the sheet heating element 1 by the electrical insulation film 7, and safety is further improved.

  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 substrates 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 a heater for an automobile seat. 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.

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

  First, a 19-copper-silver alloy wire having a diameter of 0.06 μm is stranded and electrically sewn with a sewing machine with a polyester thread to the electrically insulating base material 2 made of a polyester fiber non-woven fabric. Form. 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.

  Next, the sheet-like heating element 1 is completed by extruding the pellet of the material of the adhesive layer 8 from a T-die connected to an extrusion apparatus and pasting it with a film formed on the electrically insulating film 7 by heat fusion.

  In this way, the filament electrode 3 and the polymer resistor 4, and the electrical insulating film 7 and the polymer resistor 4 are joined by heat fusion.

  As a result, the line electrode 3 is disposed in an electrically connected state between the electrically insulating film 7 and the polymer resistor 4.

The polymer resistor 4 is made of a flexible sheet or film, so that even if an external force is applied to the planar heating element 1, the polymer resistor 4 itself responds to the external force similarly to the electrically insulating substrate 2. 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.

  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.

  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 9 and the backrest 10 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.

  The planar heating element according to the present invention has a simple structure and has flexibility to easily adapt to 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.

DESCRIPTION OF SYMBOLS 1 Planar heating element 2 Electrically insulating base material 3 Line electrode 4 Polymer resistor 5 Core wire 6 Conductive coating 7 Electrically insulating film 8 Adhesive layer 9 Seat part 10 Backrest

Claims (8)

An electrically insulating base material having flexibility, a polymer resistor comprising a resin composition and a conductor as a main component attached to the electrically insulating base material, and electrically connected to the polymer resistor body In addition, at least one pair of linear electrodes and a flexible electric material made of a resin having a smaller elastic modulus than that of a general-purpose resin are bonded to the polymer resistor via an adhesive layer whose main component is made of a thermoplastic elastomer. A planar heating element comprising an insulating film. 2. The surface according to claim 1, wherein the filament electrode is configured by covering a conductive wire composed mainly of a resin composition and a conductor on the outside of a core wire made of at least one of a metal wire and a metal braided wire. Heating element. The planar heating element according to claim 1, wherein the elastic modulus of the electrically insulating film is set to 500 MPa or less. The planar heating element according to claim 1 or 3, wherein the electrically insulating film is made of a polymer alloy containing a plant-derived component. The planar heating element according to claim 1, wherein the adhesive layer includes a flame retardant having a flame retardant property satisfying at least one of the following conditions.
(1) When the end face of the adhesive layer 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 adhesive layer burns.
(2) The end face of the adhesive layer is blown with a gas flame, and the fire is extinguished within 60 seconds and within 2 inches once the adhesive layer is lit.
(3) Even if the end face of the adhesive layer is blown by a gas flame and the adhesive layer 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. 6. The planar heating element according to claim 5, wherein the flame retardant is liquid at normal temperature or has a melting point that melts at a kneading temperature, and comprises at least one of a phosphorus-based, nitrogen-based, and silicone-based compound. A seat equipped with the planar heating element according to any one of claims 1 to 6 as a heating heat source. The seat according to claim 7, wherein a planar heating element is disposed on at least one of the seat portion and the backrest so that the electrically insulating base material is on the surface side.

Images