JP2011003328A - Polymer heating element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymer heating element which can be used safely, even when external deformation stress is applied to an electrode section or a resistor section and even when an abnormal overheat occurs due to power concentration.SOLUTION: The polymer heating element includes overheat protection means 5a, 5b connected to a part of a pair of electrodes 3a, 3b connected to a polymer resistor 4, arranged on an electric insulation substrate 2 with PTC characteristics. Thus, when the polymer resistor 4 reaches a predetermined temperature or higher, the overheat protection means 5a, 5b are able to block the current supply to the electrodes 3a, 3b which are connected to the resistor 4.

Description

  The present invention relates to a polymer heating element using Joule heat of a polymer resistor.

  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, when a PTC (Positive Temperature Coefficient) heating element that exhibits a self-temperature control function is used by combining a conductive material and a resin, there is an advantage that a temperature control circuit is not required and the number of parts can be reduced. Known as a device.

  Specifically, as shown in FIGS. 9 and 10, electrodes 102a and 102b are formed by printing or applying a conductive ink composition on a base material 101 having a function as a casing structure such as a ceramic or an insulating metal plate. The resistor 103 is provided by printing or applying the resistor ink composition at a position where power is supplied.

  Examples of conventional polymer resistors formed by printing and used as heating elements include automobile door mirrors, washstand mirrors, floor heating appliances, etc. (for example, patent documents) 1).

JP 2002-371699 A

  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 applications where flexibility and flexibility are required, the ability of the resistor and the electrode to sufficiently cope with external deformation stress is required, and from the viewpoint of materials, 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 the resistor is forced to bend due to external stress, and the electrode part is in a disconnected state or close to a disconnected state, a normal voltage is applied to the portion between the disconnected portion and the power supply side, and the disconnected portion Since power is not supplied to the part beyond the part, a momentary voltage drop occurs, and a spark phenomenon occurs due to the contact or non-contact state of the electrode at the disconnected part, causing local temperature overheating.

  In particular, a planar heating element having PTC characteristics has a high resistance value at a high temperature and a low resistance value at a low temperature. Therefore, when current supply is started in a low temperature environment, the heating element itself rises in temperature. Compared to the above, a large inrush current flows.

  Although depending on the material composition of the heating element and the ambient temperature, a difference of about 2 to 5 times may occur with respect to a stable current value.

  There is no problem even if a current of several amperes flows by reviewing the strength and structure of the electrode wire, but if there is a disconnection or a state close to disconnection in a part of the electrode part, current concentration occurs at that part In addition, since the surrounding material exhibits PTC characteristics, current concentration due to an increase in resistance value further occurs, and in the case of abnormal overheating, there is a possibility that smoke may be ignited depending on the subsequent state.

  For this reason, it is easy to take measures such as a method of controlling current using a current detection sensor and a temperature detection sensor around the electrode part, but there are installation locations and circuits for providing such sensors. Therefore, the advantage of the PTC heating element that can reduce the number of parts is lost.

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a safe polymer heating element that is comfortable and considers energy saving.

  The polymer heating element of the present invention for solving the conventional problems includes an electrically insulating substrate, a polymer resistor having a PTC characteristic disposed on the electrically insulating substrate, and the polymer. A pair of electrodes in contact with the resistor and an overheat protection means connected to at least a part of the electrodes are provided.

  Therefore, when the polymer resistor reaches a certain temperature or higher, the overheat protection means can cut off the current supply to the electrode connected to the polymer resistor.

  According to the present invention, the safety of the polymer heating element can be improved and the cost can be reduced.

The top view of the polymer heating element in Embodiment 1 of this invention XY sectional view of FIG. Plan view of polymer heating element in Embodiment 2 of the present invention XY cross section of FIG. The top view of the polymer heating element in Embodiment 3 of this invention XY sectional view of FIG. The top view of the polymer heating element in Embodiment 4 of this invention XY sectional view of FIG. Plan view showing a conventional polymer heating element XY cross section of FIG.

  According to a first aspect of the present invention, there is provided an electrically insulating substrate, a polymer resistor having a PTC characteristic disposed on the electrically insulating substrate, a pair of electrodes in contact with the polymer resistor, and the electrodes Overheat protection means connected to at least a part of the current, and when the polymer resistor reaches a certain temperature or higher, the current to the electrode connected to the polymer resistor by the overheat protection means Supply can be cut off.

  The shape and structure of the overheat protection means, the connection form with the electrodes, and the like are not particularly limited, and examples thereof include a method of arranging them in a linear shape in the vicinity of a pair of electrodes using a printing method.

  According to a second invention, in particular, in the first invention, the overheat protection means melts at a predetermined temperature to cut off the current supply to the electrode, and is a polymer resistor having PTC characteristics. In the polymer heating element comprising a body and a pair of electrodes, overheating protection means is provided at a position near the current supply side with respect to the pair of electrodes, causing problems such as disconnection, and temperature overheating near the electrodes When this occurs, the circuit can be safely shut off by utilizing the self-melting phenomenon of the overheat protection means.

  In the third invention, in particular, in the first or second invention, the overheat protection means is disposed at an interval of 10 mm or less from the electrode, and even when the heating element is abnormally overheated when the disconnection occurs or is about to be disconnected. By quickly transferring heat to the overheat protection means provided in the vicinity of the current supply site, the circuit can be shut off quickly.

  The fourth invention, in particular, in the second invention, the overheat protection means is composed of a resin having a melting point of 150 ° C. or lower and a conductive resin of conductive particles, and has excellent processability, An inexpensive and simple overheat protection means can be provided.

  In particular, in the fourth invention, the fifth invention includes any one of a copolymerized polyester resin and an ethylene-methacrylic acid copolymer resin as a resin component, and the overheat protection means is linear or planar, Since any form can be accurately and easily processed, a safe heating element can be provided without impairing the comfort of the planar heating element.

  In particular, the sixth invention relates to the fourth invention, wherein the conductive particles include carbon black, graphite, carbon nanotubes, carbon fibers, conductive ceramic fibers, conductive whiskers, metal fibers, conductive inorganic oxides, conductive particles. Conductive polymer fiber, containing a conductor selected from at least one kind of metal powder, exhibiting the same level of conductivity as a conductive member used as an electrode of a heating element, and also suitable for flexibility. It is possible to provide a highly reliable heating element while maintaining the comfort of the heating element.

  In the seventh invention, in particular, in the first invention, the electrically insulating base material, the electrode, the polymer resistor, and the overheat protection means have flexibility, and are restricted by a member to be heated. In addition, it is possible to provide a polymer heating element that can be applied to any place and does not deteriorate in performance over a long period of time.

  In an eighth aspect of the invention, in particular, in the first or seventh aspect of the invention, the electrically insulating substrate is made of at least one of a resin film, a woven fabric, and a non-woven fabric. Since it is possible to make a device with an excellent, extremely thin and light weight material, a polymer heating element excellent in usability and long-term reliability 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 embodiments.

(Embodiment 1)
1 and 2, the polymer heating element 1 is configured by providing a pair of electrodes 3a and 3b, a polymer resistor 4 and overheat protection means 5a and 5b on an electrically insulating substrate 2.

  More specifically, as the electrical insulating base material 2, a non-woven fabric made of finely embossed polyester fibers was used.

And the polymer resistor 4 is arrange | positioned by one side | surface of the electrically insulating base material 2 by thermal fusion,
The electrodes 3a and 3b and the overheat protection means 5a and 5b are heat-sealed to the polymer resistor 4.

  The electrode 3a and the overheat protection means 5a, and the electrode 3b and the overheat protection means 5b were each arranged in a straight line at regular intervals of 5 mm.

  The polymer resistor 4 was formed by preparing a kneaded material using the following materials and procedures and then heat-sealing it into a sheet on the electrically insulating substrate 2 by calendering.

  That is, the polymer resistor 4 includes, as a crystalline resin, 30 parts of an ethylene / methacrylic acid copolymer [trade name “Acrylift CM5021”, melting point 67 ° C., manufactured by Sumitomo Chemical Co., Ltd.], ethylene / methacrylic. 30 parts of an acid copolymer [trade name “Nucrel 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., Mitsui DuPont Polychemica Co., Ltd.] 40 parts.

  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 size 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 product A was prepared with 20 wt% of acid ester liquid flame retardant, manufactured by Ajinomoto Co., Inc.

  Next, as the elastomer, styrene thermoplastic elastomer [trade name “Tuftec M1943” manufactured by Asahi Kasei Engineering Co., Ltd.] 40% by weight, carbon black [trade name “# 10B”, primary particle diameter 75 nm, Mitsubishi Chemical Corporation 45 wt%, tungsten carbide [Izawa Metal Co., Ltd.] 13 wt%, 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 of a trade name “METABBRENE A3000” manufactured by Mitsubishi Rayon Co., Ltd.

  Then, the kneaded product A and the kneaded product B are made equal, and 2% by weight of modified silicone oil is used as a release agent, and 2% by weight of alkyl methacrylate / alkyl acrylate copolymer is used as a fluidity imparting agent. Thus, a polymer resistor 4 was produced.

  Further, as the electrodes 3a and 3b, tin-plated copper flat wires having a width of 0.5 mm and a thickness of 0.1 mm were used. Further, as the overheat protection means 5a and 5b, 40 parts of an ethylene-methacrylic acid copolymer [trade name “Nucrel N1560”, melting point 90 ° C., manufactured by Mitsui DuPont Polychemical Co., Ltd.] and carbon black (trade name “ Printex L ”, primary particle size 21 nm, manufactured by Degussa) 50% by weight and flame retardant (trade name“ Reophos RDP ”, phosphate ester type liquid flame retardant, manufactured by Ajinomoto Co., Inc.) 10% by weight. A conductive resin having a wire diameter of 0.5 mm was obtained using an extruder, and heat-sealed on the polymer resistor 4 together with the electrodes 3a and 3b.

  The electrodes 3a and 3b are formed by arranging a wide pair (electrically positive side and negative side) so as to face each other along the outer side in the longitudinal direction of the polymer resistor pair 4, and the polymer resistor 4 is caused to generate heat.

  In the present embodiment, the polymer resistor 4 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. It has a function as a high polymer heating element 1.

  In the polymer heating element 1 of the present embodiment, the polymer resistor 4 generates heat by supplying current to the electrodes 3a and 3b via the overheat protection means 5a and 5b. When a part of the electrodes 3a, 3b is broken or just before the breakage, current concentration occurs in that part, so the temperature of the polymer resistor 4 rises locally. Since the resin component, which is a constituent material of the means 5a and 5b, has a melting point or higher, a part thereof is melted, and as a result, the current supply is cut off. Thus, it was possible to obtain the temperature rise protection means 5a, 5b having a flat shape and flexibility very easily.

(Embodiment 2)
3 and 4, the polymer heating element 11 includes a pair of electrodes 13 and 13b and a polymer resistor 14 on one side of the electrically insulating substrate 12, and overheat protection means 15a and 15b on the other side. Have.

  In the present embodiment, as the electrically insulating substrate 12, a nonwoven fabric made of needle-punched polyester fibers is used.

  And the polymer resistor 14 was arrange | positioned by the heat sealing | fusion by the one side of the electrically insulating base material 12, and the electrodes 13a and 13b and the overheat protection means 15a and 15b were heat-fused to the electrical insulating base material 12 after that. .

  The electrodes 13a, 13b and the overheat protection means 15a, 15b are arranged in a straight line so as to face each other with the electrical insulating material 12 and the polymer resistor 14 in contact with each other at the upper side, and the lower side The current is supplied to the electrodes 13a and 13b through the overheat protection means 15a and 15b.

  For the polymer resistor 14, the electrodes 13a and 13b, and the overheat protection means 15a and 15b, the same materials as those obtained in the first embodiment were prepared by the same processing method.

  The electrodes 13a and 13b 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 polymer heating element 11 so as to face each other. To generate heat.

  In the present embodiment, the polymer resistor 14 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 1.

  In the polymer heating element 11, the polymer resistor 14 generates heat when current is supplied to the electrodes 13a and 13b via the overheat protection means 15a and 15b. When a part of the electrodes 13a, 13b is broken or just before the breakage, current concentration occurs in that part, so that the temperature of the polymer resistor 14 rises locally. Since the resin component 15a and 15b is a constituent material of which the melting point is higher than the melting point, a part thereof is melted and as a result, the current supply is cut off.

  Thus, it was possible to obtain the temperature rise protection means 15a, 15b having a flat shape and flexibility very easily.

  Further, since the electrically insulating base 12 is present between the electrodes 13a and 13b and the overheat protection means 15a and 15b, there is no need to be particularly careful about the contact state between them, and a flexible heating element can be obtained. Is.

(Embodiment 3)
5 and 6, the polymer heating element 21 has a pair of electrodes 23a, 23b, a polymer resistor 24, and overheat protection means 25a, 25b on one side surface of the electrically insulating substrate 22.

  In the present embodiment, a polyethylene terephthalate film (film thickness: 125 μm) is used as the electrically insulating substrate 22.

  The pair of electrodes 23 a and 23 b that are electrically on the positive side and the negative side were formed by printing and drying a conductive paste on the electrically insulating base 22. The conductive paste used was a dispersion of silver powder as a conductivity-imparting material in a copolyester resin.

  In addition, the polymer resistor 24 is manufactured to have an exothermic temperature of about 40 ° C., and two types of ethylene vinyl acetate copolymers are combined, and carbon black is kneaded and crosslinked with acrylonitrile butyl rubber as a binder. It is obtained by forming an ink with a solvent, and is formed by printing and drying on the surface on which the electrodes 23a and 23b are formed.

  The electrodes 23a and 23b have a comb-like shape in which a pair of wide main electrode portions so as to face each other and a plurality of branch electrode portions are led out alternately from the respective main electrode portions toward the main electrode portion on the other side. By arranging the polymer resistor 24 so as to overlap with this, when a power is supplied from a large number of branch electrode portions, a current flows through the resistor to generate heat.

  As overheat protection means 25a, 25b, copolymer polyester resin [trade name “Byron GM920”, melting point 106 ° C., manufactured by Toyobo Co., Ltd.] 30 parts, conductive whisker [trade name “FTL-110”, Acicular titanium oxide, manufactured by Ishihara Sangyo Co., Ltd.] 35% by weight, carbon black (trade name “Printex L”, primary particle size 21 nm, manufactured by Degussa) 25% by weight, flame retardant [trade name “Reophos RDP” , A phosphoric ester-based liquid flame retardant, manufactured by Ajinomoto Co., Inc.] 10% by weight to prepare a kneaded product, to obtain a conductive resin having a wire diameter of 0.5 mm using an extruder, as shown in FIG. A polymer heating element 21 was obtained by heat-sealing on the electrically insulating substrate 22 so as to be parallel to the longitudinal direction of the main electrode portions of the electrodes 23a and 23b.

  In the present embodiment, the polymer resistor 24 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 1.

  In the polymer heating element 21, the polymer resistor 24 generates heat by supplying current to the electrodes 23a and 23b via the overheat protection means 25a and 25b.

  When a part of the electrodes 23a, 23b is broken or just before the breakage, current concentration occurs in that part, so that the polymer resistor 24 locally rises in temperature. Since the resin component 25a and 25b has a melting point or higher, a part thereof is melted, and as a result, the current supply is cut off.

  Thus, it was possible to obtain a temperature rise protection means having a planar shape and flexibility very easily.

(Embodiment 4)
7 and 8, a polymer heating element 31 includes a pair of electrodes 33a and 33b and a polymer resistor 34 on one side of an electrically insulating substrate 32, and overheat protection means 35a and 35b on another side. Have.

  In the present embodiment, a polyethylene terephthalate film (film thickness: 125 μm) is used as the electrically insulating substrate 32.

  The electrodes 33a and 33b and the polymer resistor 34 are arranged on one side of the electrically insulating substrate 32 by the same printing method as in the third embodiment, and the overheat protection means 35a and 35b are arranged as shown in FIG. It was heat-sealed to the insulating substrate 32.

  The electrodes 33a, 33b and the overheat protection means 35a, 35b are arranged in a straight line so as to face each other with the electrical insulating equipment 32 and the polymer resistor 34 in contact with each other at the upper side shown in the figure, and the lower side part Current is supplied to the electrodes 33a and 33b through the overheat protection means 35a and 35b.

  Here, the connecting portions between the electrodes 33a and 33b and the overheat protection means 35a and 35b are indicated by black circles.

  The polymer resistor 34, the electrodes 33a and 33b, and the overheat protection means 35a and 35b were made of the same material as that obtained in the third embodiment by the same processing method.

  The electrodes 33a and 33b 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 sheet heating element 31 so as to face each other. To generate heat.

  In the present embodiment, the polymer resistor 34 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 31.

  In the planar heating element 31, the polymer resistor 34 generates heat when current is supplied to the electrodes 33a and 33b via the overheat protection means 35a and 35b. When a part of the electrodes 33a and 33b is broken or just before the breakage, current concentration occurs in that part, so that the polymer resistor 34 locally rises in temperature, and overheat protection is performed at about 120 ° C or higher. Since the resin component, which is a constituent material of the means 35a and 35b, has a melting point or higher, a part thereof is melted, and as a result, the current supply is cut off.

  Thus, it was possible to obtain a temperature rise protection means having a planar shape and flexibility very easily. Further, in the case of the configuration shown in the figure, since the electrically insulating base material 32 exists between the electrodes 33a and 33b and the overheat protection means 35a and 35b, it is not necessary to be particularly cautious about the contact state between them, and flexibility A heating element can be obtained.

  As described above, in the polymer heating element according to the present invention, when the electrode part or the resistor part is subjected to a deformation stress from the outside, even when abnormal overheating occurs due to electric power concentration or the like, the heating protection means is quickly provided. In addition, since temperature abnormality can be recognized by simple means, it can be used with peace of mind. Therefore, the present invention can also be applied to an abnormal overheat protection means for a heat generating device in which the input current is increased.

11, 21, 31 Polymer heating element 2, 12, 22, 32 Electrically insulating base 3a, 3b, 13a, 13b, 23a, 23b, 33a, 33b Electrode 4, 14, 24, 34 Polymer resistor 5a, 5b, 15a, 15b, 25a, 25b, 35a, 35b Overheat protection means

Claims (8)

An electrically insulating substrate, a polymer resistor having PTC characteristics disposed on the electrically insulating substrate, a pair of electrodes in contact with the polymer resistor, and connected to at least a part of the electrodes A polymer heating element comprising the overheat protection means. The polymer heating element according to claim 1, wherein the overheat protection means melts at a predetermined temperature to cut off the current supply to the electrode. The polymer heating element according to claim 1 or 2, wherein the overheat protection means is disposed at an interval of 10 mm or less from the electrode. The polymer heating element according to claim 2, wherein the overheat protection means comprises a resin having a melting point of 150 ° C or lower and a conductive resin of conductive particles. The polymer heating element according to claim 4, wherein the resin component contains any one of a copolymerized polyester resin and an ethylene-methacrylic acid copolymer resin. A conductive material selected from at least one of carbon black, graphite, carbon nanotube, carbon fiber, conductive ceramic fiber, conductive whisker, metal fiber, conductive inorganic oxide, conductive polymer fiber, and metal powder as the conductive particles. The polymer heating element according to claim 4 comprising. The polymer heating element according to claim 1, wherein the electrically insulating substrate, the electrode, the polymer resistor, and the overheat protection means have flexibility. The polymer heating element according to claim 1 or 7, wherein the electrically insulating substrate comprises at least one of a resin film, a woven fabric, and a nonwoven fabric.