JP2009266631A - Polymer exothermic body - Google Patents

Abstract

[PROBLEMS] To provide a polymer resistor exhibiting low resistance capable of being thin-walled to improve flexibility and usability and reliability of a planar heating element when mounted on a device, and to reduce costs. An object of the present invention is to provide a polymer heating element.
A polymer resistor 2 having PTC characteristics, and a pair of electrodes 3 and 3 'formed of a plurality of thin metal wires 3 and 3' and covered with conductive coating layers 5 and 5 ' In the polymer heating element 1, the pair of electrodes 3 and 3 ′ are disposed on both sides of the polymer resistor 2.
[Selection] Figure 1

Description

  The present invention relates to a polymer heating element using Joule heat of a polymer resistor, and more particularly to a polymer heating element that has long-term reliability and can be produced at low cost.

  2. Description of the Related Art Conventionally, as a heat generating portion of a planar heating element, a material obtained by dispersing a conductive material such as carbon black, metal powder, or graphite in a resin is known. In particular, in the case of using a PTC heating element (which means an abbreviation of English Positive Temperature Coefficient, which means a positive resistance temperature characteristic) by a combination of a conductive material and a resin, a temperature control circuit is provided. Is known as a device that has advantages such as eliminating the need for components and reducing the number of components.

  As shown in FIGS. 7 and 8, the electrode 32 is formed by printing or applying a conductive ink composition on a base material 31 having a function as a housing structure such as a ceramic or an insulating metal plate. And the resistor ink composition is printed or applied to the position where power is supplied, thereby providing the polymer resistor 33 to form the heating element 34.

Conventionally, examples in which a polymer resistor is formed by printing and used as a heating element include a door mirror of an automobile, a mirror of a wash basin, a floor heater, etc. for dew / frost removal (for example, Patent Document 1). reference).
JP 2002-371699 A

  In the conventional configuration, the specific resistance of the resistor composition to be used is usually 1000 Ω · cm or more, so that power is supplied very close like a comb electrode.

  In general, the comb-shaped electrode is made of silver paste, and is formed by printing and drying. Therefore, the amount of the comb-shaped electrode increases, so that the comb electrode is expensive.

  In the case where a polymer resistor is manufactured as an ink, the heat generating portion can be formed in a thin film of about several tens of micrometers by adjusting the coating amount, and therefore it is easy to exhibit flexibility as a polymer heating element.

  However, it is necessary to use a smooth, non-impregnated, and electrically insulating base material such as a polyester film with a waist as the surface on which the ink-like polymer resistor is applied, resulting in a loss of flexibility. It was.

  Further, since it is necessary to use a large amount of expensive conductive paste as a comb-shaped electrode as a power feeding portion of the polymer heating element, there is a disadvantage that the cost is high.

  On the other hand, the resistor used for extrusion molding is thicker in millimeters than the one used for the ink, lacks flexibility, and has a configuration in which the electrode cables are close to each other, so it cannot be said to be a planar heating element.

  There are thin-wall molding methods such as T-die extrusion and calendering, but no polymer resistor suitable for these methods has been proposed.

  In view of the above-mentioned problems of the prior art, the problem to be solved by the present invention is to improve the usability and reliability of a planar heating element when a polymer resistor exhibiting low resistance capable of thin molding is provided. At the same time, it is an object to provide a polymer heating element that is reduced in cost.

  The polymer heating element of the present invention for solving the conventional problems is a pair of electrodes composed of a polymer resistor having PTC characteristics and a plurality of fine metal wires and covered with a conductive coating layer. And the pair of electrodes are arranged on both surfaces of the polymer resistor.

  In the present invention, a polymer resistor having a low resistance is basically formed in a thin film. However, this configuration eliminates the need for a comb-shaped configuration between the electrodes that feed the polymer resistor, and thus wide. Electrodes can be arranged at intervals, and the amount of electrodes used can be reduced, and it is not necessary to pattern the polymer resistor, so that a low-cost planar heating element can be provided.

  In a normal sheet heating element, there is a pair of electrodes for the heating part. When no deformation stress is applied to the heating element from the outside and flexibility and flexibility are not required, the resistor serving as the heating section and the electrode serving as the power supply section do not undergo shape deformation from the time of processing.

  On the other hand, in the case of usage that requires flexibility and flexibility, the resistor and the electrode are required to be able to cope with deformation stress from the outside. It is necessary to propose a proper formulation.

  When a load more than expected is applied to the resistor or electrode, disconnection occurs, and as a result, heat is not generated, but current concentration may occur due to a part of the electrode being cut off as a transient state. Although it occurs, a device that does not cause this phenomenon is also extremely important.

  For example, when a resistor is forced to bend due to external stress, both sides of the resistor contract with respect to the external force and one side expands while the other is designed with a thin film Will be.

  By arranging a pair of electrodes on both sides of the resistor as shown in the present invention, even if a failure occurs in the electrode in contact with one surface, there is an electrode in contact with the other surface. Current concentration just before the moment does not occur in the electrode, so it does not occur.

  In addition, since the probability that the electrodes disposed on both sides are disconnected at the same location on both the front and back surfaces is low, a polymer heating element exhibiting extremely high reliability can be provided as a result.

  As a further contrivance: 1. Shift the electrode bonding position on the front and back surfaces. 2. Change the material. A pattern at the time of bonding, for example, a straight line on the front surface and a meandering line on the back surface can be considered, and such a pattern may be used.

  According to the present invention, it is possible to provide a planar heating element having a thin film and a low resistance, to improve reliability, and to promote cost reduction.

1st invention comprises the polymer resistor which has a PTC characteristic, and a pair of electrode comprised with the several metal fine wire and coat | covered with the electroconductive coating layer, The said pair of electrodes is said polymer | macromolecule It is arranged on both sides of the resistor, eliminating the need for a comb-shaped configuration between the electrodes that feed the resistor composition, making it possible to arrange the electrodes at wide intervals and reducing the amount of electrodes used. It is possible to provide a low-cost planar heating element since the polymer resistor is not required to be reduced and patterned.

  Further, a complicated construction method is not required, and the electrode can be easily manufactured by bonding the electrode to a polymer resistor obtained by a T-die, a calendar roll method, or the like by thermal fusion or the like.

  Furthermore, by providing a pair of electrodes composed of a plurality of fine metal wires and covered with a conductive coating layer on both the front and back surfaces of the polymer resistor, durability such as flexibility can be improved.

  According to a second aspect of the present invention, in the first polymer heating element, the conductive coating layer includes a resin component having a functional group exhibiting metal affinity, and at the interface between the conductive layer and the metal serving as the electrode. Since the contact state can be kept good, a heating element with good heat generation characteristics can be easily obtained.

  According to a third invention, in particular, in the polymer heating element of any one of the first and second inventions, the conductive coating layer contains a conductor component of 50 wt% or more and 80 wt% or less.

  Since the conductor is included in the conductive layer at this weight ratio, even when the electrode made of a thin metal wire is disconnected, the presence of a larger amount of the conductor component than the resin component causes disconnection and current concentration. , Can suppress the occurrence of sparks. Moreover, since it will contain 20 weight% or more of a resin component and an additive component by setting it as 80 weight% or less, the flexibility as a conductive layer and a certain amount of softness | flexibility can be hold | maintained.

  In the fourth invention, in particular, in the polymer heating element of any one of the first to third inventions, the conductive component of the conductive coating layer is carbon black, graphite, carbon nanotube, carbon fiber, conductive ceramic fiber. It is made of a conductor selected from at least one of conductive whisker, metal fiber, conductive inorganic oxide, and conductive polymer fiber, and the raw material of the conductor can be obtained relatively inexpensively and stably. Can be provided.

  In the fifth invention, in particular, in the polymer heating element of any one of the first to fourth inventions, the conductive coating layer contains at least one flame retardant component of phosphorus, nitrogen, and silicone. Thus, even when heated from the outside, even if the electrode wire is disconnected and the temperature rises locally, a polymer heating element capable of suppressing smoke and ignition can be provided.

  In the sixth aspect of the invention, in particular, in the polymer heating element of any one of the first to fifth aspects, the specific resistance of the conductive layer is 0.01 to 500 Ω · cm, and the heat loss in the conductive layer is small. An electrically stable polymer heating element can be produced.

  In order to make it smaller than 0.01 Ω · cm, it is necessary to increase the ratio of the conductor. However, in this case, the resin ratio as the binder is decreased, so that the adhesion with the metal is decreased.

  On the other hand, if it exceeds 500 Ω · cm, the resistance value of the conductive layer becomes larger than that of the polymer resistor when a voltage is applied, and only the conductive layer generates heat, and a planar heating element cannot be obtained.

  In the seventh invention, in particular, in the polymer heating element of the first invention, the metal of the thin metal wire is made of at least one of tin-plated copper, silver-containing copper wire, or silver-copper alloy, and the metal itself is also flexible and bent. Therefore, a polymer heating element having good heat generation characteristics can be provided for a long time.

  In an eighth aspect of the present invention, in the polymer heating element of the first aspect of the invention, at least one surface of the polymer resistor has an electrically insulating substrate made of at least one of a resin film, a woven fabric, and a non-woven fabric. A polymer heating element having excellent usability and long-term reliability can be obtained.

  According to a ninth aspect of the invention, the polymer heating element according to any one of the first to eighth aspects is mounted on an automobile seat device and used for heating a driver or the like.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited by this embodiment.

(Embodiment 1)
1 and 2, the polymer heating element 1 is configured by arranging electrodes 3 and 3 'on both sides of the polymer resistor 2, and each of these electrodes 3 and 3' is composed of the polymer resistor 2. It is equipped with a pair on both sides.

  These electrodes 3, 3 'are each formed by a plurality of fine metal wires 4, 4' and conductive coating layers 5, 5 '.

  As the fine metal wires 4 and 4 ′, those obtained by twisting 15 silver-copper alloy wires having a wire diameter of 0.06 mm were used.

  This was covered with conductive coating layers 5 and 5 ′ prepared in the following procedure to form electrodes 3 and 3 ′ and heat-sealed with polymer resistor 2 to obtain polymer heating element 1. .

  A lead wire for supplying power to the electrodes 3 and 3 'is omitted.

  The conductive coating layers 5 and 5 ′ have 21% by weight of ethylene vinyl acetate copolymer (trade name “Evaflex EV150”, manufactured by Mitsui DuPont Polychemical Co., Ltd.) as a resin component and exhibit metal affinity. Resin containing maleic anhydride as a functional group (trade name “Bondaine LX4110” (ethylene-acrylic ester-maleic anhydride terpolymer resin, manufactured by Sumitomo Chemical Co., Ltd.) Whisker (trade name “FTL-110”, acicular titanium oxide, manufactured by Ishihara Sangyo Co., Ltd.) 45% by weight, carbon black (trade name “Printex L”, primary particle diameter 21 nm, manufactured by Degussa) 15% by weight After preparing a kneaded material with 10% by weight of a flame retardant (trade name “Reophos RDP”, phosphate ester liquid flame retardant, manufactured by Ajinomoto Co., Inc.), coating and kneading fine metal wires 4, 4 ′, To obtain an electrode 3, 3 'of only 800μm.

  At this time, the specific resistance between the outer periphery of the coating and the central metal part was 5 Ω · cm.

  The polymer resistor 2 was prepared by preparing a kneaded material with the following materials and procedures and then processing it into a film by calendering.

  That is, the polymer resistor 2 is composed of 30 parts of ethylene / methyl methacrylate copolymer (trade name “ACRIFFT CM5021”, melting point 67 ° C., manufactured by Sumitomo Chemical Co., Ltd.) as a crystalline resin, and ethylene / methacrylic. 30 parts of an acid copolymer (trade name “Nucleel N1560”, melting point 90 ° C., manufactured by Mitsui DuPont Polychemical Co., Ltd.) and a metal coordination product of ethylene / methacrylic acid copolymer (trade name “HIMILAN 1702”, Melting point 90 ° C., 40 parts by Mitsui DuPont Polychemica Co., Ltd.

35% by weight of this crystalline resin, 2% by weight of a reactive resin (trade name “Bond First 7B”, manufactured by Sumitomo Chemical Co., Ltd.), and carbon black (trade name “Printex L” as two types of conductors) Primary particle diameter 21 nm, manufactured by Degussa) 25% by weight, graphite (trade name “GR15”, scaly graphite, manufactured by Nippon Graphite Co., Ltd.) 18% by weight, flame retardant (trade name “Reophos RDP”, phosphorus A kneaded material A was prepared with 20% by weight of an acid ester liquid flame retardant, manufactured by Ajinomoto Co., Inc.

  Next, as the elastomer, styrene thermoplastic elastomer (trade name “Tuftec M1943”), 40% by weight, manufactured by Asahi Kasei Engineering Co., Ltd., carbon black (trade name “# 10B”, primary particle diameter 75 nm, Mitsubishi Chemical) Co., Ltd.) 45% by weight, tungsten carbide (Izawa Metal Co., Ltd.) 13% by weight, and a mixture of an alkyl methacrylate / alkyl acrylate copolymer and a tetrafluoroethylene copolymer as a melt tension improver. A kneaded product B was prepared from 2% by weight (trade name “METABBRENE A3000”, manufactured by Mitsubishi Rayon Co., Ltd.).

  Then, an equal amount of the kneaded material A and the kneaded material B were kneaded with 2% by weight of modified silicone oil as a release agent and 2% by weight of an alkyl methacrylate / alkyl acrylate copolymer as a fluidity imparting agent. Polymer resistor 2 was produced.

  As shown in FIGS. 3 and 4, the planar heating element 1 is used by being attached to a seat portion 7 and a backrest 8 constituting a seat device 6 of an automobile as a heater for seat heating.

  In order to correspond to the suspending part (not shown) of the seat part 7 and the backrest 8, an ear part for suspending to the center part or the peripheral part is provided, but is omitted here.

  Further, the seat portion 7 and the backrest 8 to which such a planar heating element 1 is attached are generally deformed when a load is applied by a human body seated on the seat, such as a urethane pad that is restored when the load is no longer applied. The thin sheet heating element 1 provided with the seat base 9 and the seat skin 10 must be similarly deformed corresponding to the deformation of the seat 7 and the backrest 8 described above.

  For this purpose, it is needless to say that various heat generation pattern designs and the arrangement shapes of the electrodes 3 and 3 ′ need to be changed, but they are omitted here.

  The electrodes 3 and 3 ′ are arranged so that a wide pair (electrically positive side and negative side) is arranged along the outer side in the longitudinal direction of the planar heating element 1 so as to be opposed to each other, and come into contact therewith. A current flows through the arranged polymer resistor 2 to generate heat.

  In the present embodiment, the polymer resistor 2 has a PTC characteristic, and when the temperature rises, the resistance value rises, and has a self-temperature adjusting function so as to reach a predetermined temperature, and temperature control is unnecessary. It has a function as the highly safe planar heating element 1.

  Moreover, as a heater incorporated in the vehicle seat apparatus 6, a seating feeling and a flame retardance can be satisfied.

  The seating feeling can be satisfied by the fact that 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 5% elongation.

  Further, the planar heating element 1 having PTC characteristics can exhibit quick heat and energy saving performance as compared with a conventional heating element using a tubing heater.

  A tube heater that uses a heating element requires a temperature controller and controls the heat generation temperature by controlling energization by ON-OFF control.

  Since the heater wire temperature at the time of ON rises to about 80 ° C., it is necessary to arrange the heater wire at a certain distance from the seat skin material, whereas in the planar heating element 1 of the present embodiment, the heating temperature Is self-controlled within the range of 40 ° C. to 50 ° C., it can be placed close to the seat skin material.

  Since the heat generation temperature is low and it is in the vicinity of the seat, it is possible to realize energy saving by being able to reduce heat loss and heat dissipation loss to the outside.

  Flame retardancy is the automotive interior material flame retardant standard FMVSS302 (single fire extinguishing as well as nonflammability due to horizontal ignition, or if the burning rate between marked lines is 80 mm / min or less It was confirmed that it can be met if the amount of the flame retardant is at least 10% by weight.

  The planar heating element 1 obtained in this example was subjected to an 80 ° C. oven standing test, a 150 ° C. oven standing test, and a −20 ° C. and 50 ° C. heat cycle test.

  As a result, the resistance value change rate was within 30% of the initial value after 500 hours, 200 hours and 200 times, respectively.

  The reason for this was considered to be that the crystalline resin itself and the bonding between the crystalline resin and the conductor were attempted by a crosslinking reaction with the reactive resin.

  In this embodiment, a combination of a plurality of conductors and a sea-island configuration are applied in order to exhibit excellent PTC characteristics. The details of the mechanism are currently unknown, but are presumed as follows.

  First, in order to obtain a resistor composition having PTC characteristics, it is necessary to select a crystalline resin to be used whose melting point is in the vicinity of the exothermic saturation temperature.

  The conductor is required to achieve a predetermined resistance value with the smallest possible addition amount, but such a conductor is generally called conductive carbon black, and has a primary particle diameter of about 20 nm or less and a structure. (It is an aggregate of primary particles such as a bunch of coral, which is correlated with oil absorption.) On the other hand, such conductive carbon black exhibits PTC characteristics. It had the disadvantage of being difficult to do.

  This is because the structure of conductive carbon black is developed, and the conductive path of the structure is not easily cut even by the change in specific volume due to the temperature of the crystalline resin (which is said to be the main cause of the PTC characteristics). It is said.

  On the other hand, the inventors have obtained as knowledge that carbon black having a large primary particle diameter has excellent PTC characteristics.

  In addition, a conductor such as graphite has a particle size larger than that of carbon black and has a layered structure such as a scale, and has a large particle size such as metal or ceramic, and has excellent amorphous conductivity. By combining these multiple conductors, the thickness is about 100 microns or less and the sheet resistance is 400 Ω □ or less. Further, the specific resistance is 3 Ω · cm or less, and the ratio of the resistance value at 50 ° C. to the resistance value at 20 ° C., which is one index of the PTC characteristics, is 1.5 or more and 80 against the resistance value at 20 ° C. A resistor composition having a resistance value ratio of 5 or more could be obtained.

  Although the details of the mechanism that was able to demonstrate excellent PTC characteristics while being low resistance are unknown, the formation of a new conductive path by combining a crystalline resin and a plurality of conductors, and the flame retardant made liquid This is considered to be due to the fact that the large thermal expansion coefficient of the liquid could be used.

  It goes without saying that waxes such as montanic acid partly saponified esters, and plasticizers and dispersants such as other waxes may be used as necessary.

  Further, although the conductor is formed using a whisker shape, it may be spherical or other rug shape.

(Embodiment 2)
5 and 6, the polymer heating element 11 is configured by arranging electrodes 13 and 13 ′ on both sides of the polymer resistor 12, and each of these electrodes 13 and 13 ′ is composed of the polymer resistor 12. It is equipped with a pair on both sides.

  In addition, an electrically insulating substrate 16 is provided on one side of the polymer resistor 12.

  The electrodes 13 and 13 'are formed by a plurality of fine metal wires 14 and 14' and conductive coating layers 15 and 15 ', respectively.

  Although the polymer resistor 12 and the electrically insulating base material 16 are not in contact with each other, actually, the electrodes 13 and 13 'are extremely thin, so that a contact in most parts can be obtained.

  For example, the electrically insulating substrate 16 is a fine embossed material made of polyester fiber, and a nonwoven fabric impregnated with a flame retardant can be used.

  As the thin metal wires 14 and 14 'of the electrodes 13 and 13', those obtained by twisting 19 tin-plated copper wires having a wire diameter of 0.08 mm were used.

  This is covered with conductive coating layers 15 and 15 ′ prepared in the following procedure to form electrodes 13 and 13 ′, and the electrodes 13 and 13 ′ are heat-sealed on both sides of the polymer resistor 12. Thus, the polymer heating element 11 was obtained, and then bonded to the electrically insulating substrate 16.

  Note that lead wires for supplying power to the electrodes 13 and 13 'are omitted.

  The conductive coating layers 15 and 15 'have a metal affinity as an ethylene vinyl acetate copolymer (trade name "Evaflex EV150", manufactured by Mitsui DuPont Polychemical Co., Ltd.) as a resin component. Resin containing a functional group (trade name “Tuftec M1943” (modified type of hydrogenated styrene thermoplastic elastomer, manufactured by Asahi Kasei Co., Ltd.) 9% by weight as a conductor, conductive whisker (trade name “FTL-110”) , Acicular titanium oxide, manufactured by Ishihara Sangyo Co., Ltd., 30% by weight, carbon black (trade name “Furness Black # 10B”, particle size 84 nm, manufactured by Mitsubishi Chemical Corporation), 30% by weight, flame retardant (trade name “ After preparing a kneaded product with 10% by weight of “Reophos RDP”, phosphate ester liquid flame retardant, manufactured by Ajinomoto Co., Inc., the fine metal wires 14, 14 ′ were coated and kneaded to introduce a 900 μm thick lead. Electrically coated electrodes 13 and 13 'were obtained, and the specific resistance between the outer periphery of the coating and the central metal portion was 3 Ω · cm.

  The polymer resistor 12 was processed by the same method as in the first embodiment.

  In this embodiment, the polymer resistor 12 has PTC characteristics, and when the temperature rises, the resistance value rises, and has a self-temperature adjusting function so as to reach a predetermined temperature, and temperature control is unnecessary. It has a function as the highly safe planar heating element 11.

  In addition, as a car seat heater incorporated in an automobile seat, a seating feeling and flame retardancy can be satisfied.

  The seating feeling can be satisfied by the fact that 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 5% elongation.

  Further, as a planar heating element having PTC characteristics, quick heat and energy saving can be exhibited as compared with a conventional heating element using a tubing heater.

  A tube heater that uses a heating element requires a temperature controller and controls the heat generation temperature by controlling energization by ON-OFF control.

  Since the heater wire temperature at the time of ON rises to about 80 ° C., it is necessary to dispose it at a certain distance from the seat skin material. On the other hand, in the planar heating element of this embodiment, the heating temperature is high. Since it is self-controlled in the range of 40 ° C. to 50 ° C., it can be arranged close to the seat skin material. Since the heat generation temperature is low and it is in the vicinity of the seat, it is possible to realize energy saving by being able to reduce heat loss and heat dissipation loss to the outside.

  Further, flame retardancy can be realized by using a flame retardant nonwoven fabric for the electrically insulating base material 16 and blending a flame retardant with the polymer resistor 12 and the conductive coating layers 15 and 15 ′.

  Flame retardancy is the automotive interior material flame retardant standard FMVSS302 (single fire extinguishing as well as nonflammability due to horizontal ignition, or if the burning rate between marked lines is 80 mm / min or less It was confirmed that it can be met if the amount of the flame retardant is at least 10% by weight.

  The planar heating element 11 obtained in this example was subjected to an 80 ° C. oven standing test, a 150 ° C. oven standing test, and a −20 ° C. and 50 ° C. heat cycle test.

  As a result, the resistance value change rate was within 30% of the initial value after 500 hours, 200 hours, and 200 times, respectively.

  The reason for this was considered to be that the crystalline resin itself and the bonding between the crystalline resin and the conductor were attempted by a crosslinking reaction with the reactive resin.

(Embodiment 3)
The polymer heating element according to the third embodiment of the present invention has the same structure as that of the second embodiment.

  For example, the electrically insulating substrate 16 is a fine embossed material made of polyester fiber, and a nonwoven fabric impregnated with a flame retardant can be used.

  As the fine metal wires 14 and 14 'of the electrodes 13 and 13', those obtained by arranging 19 silver-copper alloy wires containing 3% silver having a wire diameter of 0.06 mm in parallel were used.

This is covered with conductive coating layers 15 and 15 'prepared by the following procedure to form electrodes 13 and 13'.
After heat-sealing the electrodes 13 and 13 ′ on both surfaces of the polymer resistor 12, the polymer heating element 11 was obtained by bonding to the electrically insulating base material 16.

  Note that lead wires for supplying power to the electrodes 13 and 13 'are omitted.

  The polymer resistor 12 was processed by the same method as in the first embodiment.

  The conductive coating layers 15 and 15 'are the same as those in the first embodiment.

  In the present embodiment, the polymer resistor 12 has a PTC characteristic, and when the temperature rises, the resistance value rises, and has a self-temperature adjusting function so as to reach a predetermined temperature, and temperature control is unnecessary. It has a function as the highly safe planar heating element 11.

  In addition, as a car seat heater incorporated in an automobile seat, a seating feeling and flame retardancy can be satisfied.

  The seating feeling can be satisfied by the fact that 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 5% elongation.

  Further, as a planar heating element having PTC characteristics, quick heat and energy saving can be exhibited as compared with a conventional heating element using a tubing heater.

  A tube heater that uses a heating element requires a temperature controller and controls the heat generation temperature by controlling energization by ON-OFF control.

  Since the heater wire temperature at the time of ON rises to about 80 ° C., it is necessary to dispose it at a certain distance from the seat skin material. On the other hand, in the planar heating element of this embodiment, the heating temperature is high. Since it is self-controlled in the range of 40 ° C. to 50 ° C., it can be arranged close to the seat skin material. Since the heat generation temperature is low and it is in the vicinity of the seat, it is possible to realize energy saving by being able to reduce heat loss and heat dissipation loss to the outside.

  Further, flame retardancy can be realized by using a flame retardant nonwoven fabric for the electrically insulating base material 16 and blending a flame retardant with the polymer resistor 12 and the conductive coating layers 15 and 15 ′.

  Flame retardancy is the automotive interior material flame retardant standard FMVSS302 (single fire extinguishing as well as nonflammability due to horizontal ignition, or if the burning rate between marked lines is 80 mm / min or less It was confirmed that it can be met if the amount of the flame retardant is at least 10% by weight.

  The planar heating element 11 obtained in this example was subjected to an 80 ° C. oven standing test, a 150 ° C. oven leaving test, and a −20 ° C. and 50 ° C. heat cycle test.

  As a result, the resistance value change rate was within 30% of the initial value after 500 hours, 200 hours and 200 times, respectively. The reason for this was considered to be that the crystalline resin itself and the bonding between the crystalline resin and the conductor were attempted by a crosslinking reaction with the reactive resin.

  As described above, the planar heating element according to the present invention has high flexibility and high reliability, and can be used as a heating element for heating a vehicle seat device, a handle device, and other parts.

FIG. 3 is a plan view showing the configuration of the polymer heating element in the first embodiment. XY sectional view of FIG. 1 is a side view of a seat device for an automobile to which a planar heating element is attached according to Embodiment 1 of the present invention. Front view of the seating device The top view which shows the structure of the polymer heating element in this Embodiment 2. XY sectional view of FIG. Plan view showing a conventional heating element XY sectional view of FIG.

Explanation of symbols

1,11 Polymer heating element 3,3 ', 13,13' Electrode 2,12 Polymer resistor 4,4 ', 14,14' Metal fine wire 5,5 ', 15,15' Conductive coating layer 16 Electrical insulating substrate

Claims (9)

A polymer resistor having PTC characteristics, and a pair of electrodes made of a plurality of fine metal wires and covered with a conductive coating layer, the pair of electrodes on both surfaces of the polymer resistor Arranged polymer heating element. The polymer heating element according to claim 1, wherein the conductive coating layer includes a resin component having a functional group exhibiting metal affinity. 3. The polymer heating element according to claim 1, wherein the conductive coating layer contains a conductor component of 50 wt% or more and 80 wt% or less. The conductive component of the conductive coating layer is selected from at least one of carbon black, graphite, carbon nanotube, carbon fiber, conductive ceramic fiber, conductive whisker, metal fiber, conductive inorganic oxide, and conductive polymer fiber. The polymer heating element according to any one of claims 1 to 3, wherein the polymer heating element is made of a conductor. The polymer heating element according to any one of claims 1 to 4, wherein the conductive coating layer contains at least one flame retardant component of phosphorus, nitrogen, or silicone. The polymer heating element according to any one of claims 1 to 5, wherein a specific resistance of the conductive coating layer is 0.01 to 500 Ω · cm. The polymer heating element according to claim 1, wherein the metal of the thin metal wire is at least one of tin-plated copper, silver-containing copper wire, or silver-copper alloy. 2. The polymer heating element according to claim 1, wherein at least one surface of the polymer resistor has an electrically insulating substrate made of at least one of a resin film, a woven fabric, and a nonwoven fabric. An automobile seat device on which the polymer heating element according to any one of claims 1 to 8 is mounted.