JP2012084556A - Planar heating element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planar heating element in which an electrode composed of a conductive material and a heating part composed of a resistor material are not peeled off from a substrate while maintaining flexibility and elasticity, the electrode is not heated abnormally, and the heating part can ensure uniform heating.SOLUTION: The planar heating element comprises a substrate 2 having flexibility and elasticity, a pair of electrodes 3a, 3b formed of a conductive material 5 on the surface of the substrate 2, and a heating part 4 that is composed of a resistor material 6, connected electrically with the pair of electrodes 3a, 3b and has a self temperature control function. The heating part 4 is partially buried in the substrate 2 in the thickness direction by applying the resistor material 6 on the substrate 2 and then pressing the resistor material 6.

Description

  The present invention relates to a planar heating element used in an electric heating appliance such as an electric carpet, an electric blanket, a floor heating panel, and a vehicle seat heater, and particularly relates to fixing an electrode part and a heating part to a base material. is there.

  Conventionally, as shown in FIGS. 4A and 4B, this type of planar heating element 11 prints a conductive paste on an electrically insulating base material (base material) 12 such as a polyester film. A pair of comb-shaped electrodes 13 obtained by drying and a polymer resistor 14 obtained by printing and drying polymer resistor ink at a position to which power is supplied, and a base material (base material) 12; The comb-shaped electrode 13 and the polymer resistor 14 are covered and protected with a uniform coating material 15 (see, for example, Patent Document 1).

  As the polymer resistor ink for forming this polymer resistor, a base polymer and a conductive material such as carbon black, metal powder, and graphite are dispersed in a solvent. In particular, a crystalline resin is used as the base polymer. Many of them have PTC characteristics (see, for example, Patent Documents 2 and 3).

  The PTC characteristic is a resistance temperature characteristic in which the resistance value increases as the temperature rises, and when the temperature reaches a certain temperature, the resistance value rapidly increases (takes the initial letter of English Positive Temperature Coefficient, which means that the resistance has a positive temperature coefficient) The polymer resistor 14 having PTC characteristics can provide a planar heating element having a self-temperature adjusting function.

  2. Description of the Related Art Conventionally, electric heaters such as electric carpets and vehicle seat heaters are used by humans walking or sitting, and a compression load is repeatedly applied at that time.

  Because of this repeated compression load, mechanical stress such as bending or tension is applied to the surface material 20 and the sheet heating element 11 as shown in FIG. 5, and therefore the sheet heating element 11 is required to have flexibility and stretchability. Is done. However, a conventional planar heating element using a polyester film or the like as the substrate 12 has some flexibility but is not stretchable, and thus is unsuitable for the above-mentioned electric heating appliance.

  Further, a resin film such as a polyester film has a smooth surface, and the adhesive strength between the comb-shaped electrode 13 and the polymer resistor 14 and the base material 12 made of the resin film such as the polyester film is not sufficient, and bending or tensioning is performed. When the mechanical stress is applied, the comb electrode 13 and the polymer resistor 14 may be peeled off from the substrate 12.

  One method for solving these problems is to use a fibrous material such as a woven fabric, a knitted fabric or a non-woven fabric as a base material instead of a resin film such as a polyester film, and to form an electrode part on this base material. It is conceivable to prevent exfoliation from the base material by impregnating the material and the resistor material for constituting the heat generating part, or at least only the resistor material (for example, Patent Documents 4, 5, 6, 7, 8, 9). reference).

As shown in FIG. 6, a fibrous material such as a woven fabric, a knitted fabric, or a non-woven fabric has a three-dimensional gap 30 between the fibers 31 constituting the fibrous material, and is electrically conductive for forming an electrode portion. When the material 5 and the resistor material 6 for forming the heat generating portion are impregnated, the conductive material 5 and the resistor material 6 enter the gap 30.

Japanese Patent Laid-Open No. 56-13689 JP-A-6-96843 JP-A-8-120182 JP 2000-150122 A JP-A-11-214131 JP-A-11-164848 Japanese Patent Laid-Open No. 10-41053 JP-A-8-180964 JP-A-5-47457

  However, the gaps 30 between the fibers 31 constituting the fibrous material such as a woven fabric, a knitted fabric, and a nonwoven fabric are not uniform, and there are some large gaps and some small gaps, which may be blocked in the middle. Therefore, the base material 22 made of a fibrous material is impregnated with the conductive material 5 for forming the electrode portion and the resistor material 6 for forming the heat generating portion, and when viewed from the surface, it is evenly applied without any pinholes. Even though it appears to be formed, bubbles are generated inside the base material, and the amount of impregnation of the conductive material 5 and the resistor material 6 varies depending on the size of the gap 30 between the fibers 31. The density of the conductive material 5 and the resistor material 6 will vary.

  The amount of current flowing through the conductive material 5 and the resistor material 6 varies depending on the density of the conductive material 5 and the resistor material 6. That is, if the density of the conductive material 5 and the resistor material 6 is low (the amount of the conductive material and the resistor material is small), the amount of current is small, and conversely if the density of the conductive material 5 and the resistor material 6 is high. The amount of current increases (the amount of conductive material and resistor material is large).

  In other words, the amount of current flowing through the electrode portion made of the conductive material 5 and the heat generating portion made of the resistor material 6 varies, and as a result, the current i does not flow uniformly in the electrode portion. There is a possibility that variation in heat generation occurs or the electrode part partially generates abnormal heat. Further, in the case of the heat generating portion, the resistance material 6 has a low resistance value and a high resistance value, and a high density portion has a low resistance value, which causes a problem of non-uniform heat generation.

  The present invention solves the above-described conventional problems, and while maintaining flexibility and stretchability, an electrode portion made of a conductive material and a heat generating portion made of a resistor material are not peeled off from the base material. It is an object of the present invention to provide a planar heating element that does not cause abnormal heat generation and in which the heat generating portion can ensure uniform heat generation.

  In order to solve the above-described problems, a planar heating element of the present invention includes a base material having flexibility and stretchability, a pair of electrode portions made of a conductive material on the surface of the base material, and the pair of electrode portions. And a heat generating part made of a resistor material having a self-temperature control function electrically connected to the base material, the heat generating part being applied to the base material and pressurizing the base material in the thickness direction. Partially embedded.

As a result, the resistor material is laminated and pressurized before it is solidified, so a part of the resistor material enters between the materials constituting the base material, an anchor effect occurs, and the heat generating part is peeled off from the base material There is no need to do it. In addition, the resistor material is extruded in the form of a film at the time of lamination, but this film has a uniform film thickness as a whole.

  Therefore, the surface of the resistor material becomes smoother and the thickness of the non-embedded portion of the heat generating portion becomes uniform, so that the heat generation uniformity of the heat generating portion is improved.

  Since the current always flows through the shortest distance from one electrode part to the other electrode part, it is embedded in the base part of the electrode part and the heat generating part that flow while wrapping between the materials constituting the base part. Most of the current flows through the portion not embedded in the base material that can flow straight without any obstacles.

  Therefore, the current flows uniformly through the part of the electrode part and the heat generating part that is not embedded in the base material, the electrode part does not generate abnormal heat, and the heat generating part generates heat uniformly. it can.

  Furthermore, since the base material is not impregnated with the conductive material that constitutes the electrode part in the thickness direction and the resistor material that constitutes the heat generating part, it remains flexible and stretchable as a base material. As a heating element, it retains flexibility and elasticity.

  According to the planar heating element of the present invention, a part of the resistor material enters between the materials constituting the base material, the anchor effect is generated, and the heat generating portion is not peeled off from the base material.

  In addition, since the surface of the resistor material becomes smoother and the thickness of the non-embedded portion of the heat generating portion becomes uniform, the heat generation uniformity of the heat generating portion is improved.

  Furthermore, since the base material is not impregnated with the conductive material that constitutes the electrode part in the thickness direction and the resistor material that constitutes the heat generating part, it remains flexible and stretchable as a base material. Even as a heating element, flexibility and stretchability can be maintained.

Sectional drawing which shows the structure of the planar heating element in Embodiment 1 of this invention Sectional drawing which shows the structure of the planar heating element in Embodiment 2 of this invention Sectional drawing which shows the structure of the planar heating element in Embodiment 3 of this invention (A) Top view which shows the structure of the conventional planar heating element (b) xy sectional drawing of the same planar heating element Sectional view of conventional sheet heating element Partial enlarged view of a conventional sheet heating element

  The first invention is a base material having flexibility and stretchability, a pair of electrode parts made of a conductive material on the surface of the base material, and a self-temperature control function electrically connected to the pair of electrode parts A heat generating portion made of a resistor material having a resistance, and the heat generating portion is a portion in which the resistor material is applied to the substrate and pressed to be embedded in the substrate in the thickness direction.

  As a result, the resistor material is laminated and pressurized before it is solidified, so a part of the resistor material enters between the materials constituting the base material, an anchor effect occurs, and the heat generating part is peeled off from the base material There is no need to do it. In addition, the resistor material is extruded in the form of a film at the time of lamination, but this film has a uniform film thickness as a whole. From there, the film breaks and cannot be laminated).

  Therefore, the surface of the resistor material becomes smoother and the thickness of the non-embedded portion of the heat generating portion becomes uniform, so that the heat generation uniformity of the heat generating portion is improved.

  2nd invention makes the base material the resin film which planted the fiber by the flocking process in 1st invention. As a result, the conductive material constituting the electrode portion and the resistor material constituting the heat generating portion are intertwined with the implanted fibers, so that an anchor effect occurs and the electrode portion and the heat generating portion are peeled off from the base material. Nothing will happen. In addition, since the base material is a resin film, the conductive material or the resistor material does not ooze out on the side opposite to the printing surface by printing, and stable printing can be performed.

  The third invention is based on a fiber such as a woven fabric, a knitted fabric or a non-woven fabric provided with fluff on the surface in the first invention. As a result, the conductive material constituting the electrode part and the resistor material constituting the heat generating part are embedded in the fiber as the base material and entangled with the fluffy fiber, so that a stronger anchor effect is generated. The electrode part and the heat generating part are not peeled off from the substrate.

  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)
In FIG. 1, a sheet heating element 1 is configured by printing a conductive material 5 made of silver paste on a base material 2 made of nonwoven fabric and drying it to form a pair of electrode portions 3a and 3b. Further, the resistor material 6 is printed and dried between the electrode portions 3a and 3b while covering the entire surface or a part of the pair of electrode portions 3a and 3b, and the heat generating portion 4 is configured and electrically connected. State.

  The electrode portions 3a and 3b and the heat generating portion 4 are partially impregnated in the base material 2 to form the embedded portions 7a and 7b and non-embedded portions 8a and 8b which are portions not impregnated in the base material 2. Is also formed.

  The resistor material 6 is a PTC material in which a crystalline resin such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer or the like is used as a base polymer and carbon black and various additives are blended. When the temperature reaches a certain temperature, it has a self-temperature control characteristic in which the electrical resistance value increases abruptly and suppresses the amount of heat generation.

  In this configuration, in this embodiment, a non-woven fabric is used as the base material 2 as a representative example, but any other material having flexibility and stretchability may be used. Specifically, plain weave, twill weave Woven fabrics such as satin weave, flat knitted fabric, rubber knitted fabric, pearl knitted fabric, tuck knitted fabric, float knitted fabric, pile knitted fabric, lace knitted fabric, Mayer knitted fabric, etc. Fibrous materials, polyurethane-based, polyethylene-based, polyester-based, soft vinyl chloride-based, rubber-based, or mixed foam resin sheets can be used.

  Furthermore, it is possible to use the above-mentioned material in the same way by applying unevenness to the surface of the resin film.

  In addition to the silver paste, the conductive material 5 can be a material having a low volume resistivity such as a copper paste or a carbon paste.

  Examples of printing methods for the conductive material 5 and the resistor material 6 include printing methods such as offset printing, tampo printing, flexographic printing, and screen printing.

  Next, the operation and action will be described.

  In FIG. 1, when mechanical stress such as bending or tension is applied, a force is applied to separate the electrode portions 3 a and 3 b made of the conductive material 5 and the heat generating portion 4 made of the resistor material 6 from the base material 2. However, since the embedded portion 7a of the electrode portions 3a and 3b in the base material 2 and the embedded portion 7b of the heat generating portion 4 in the base material 2 are shaped to hold the fibers constituting the nonwoven fabric of the base material 2. The anchor (wrinkle) effect occurs, and the electrode portions 3a, 3b and the heat generating portion 4 are not peeled off from the base material 2.

  Although not shown, when the surface of the base material 2 is fluffed, the electrode portions 3a, 3b and the heat generating portion 4 also hold the fluffy fibers, so that the anchor effect is greater. .

  The non-embedded portion 8a above the base material 2 of the electrode portions 3a and 3b and the non-embedded portion 8b above the base material 2 of the heat generating portion 4 have a uniform thickness, and the conductive material 5 and the resistor material 6 Therefore, the current i flows uniformly in the non-embedded portion 8b of the heat generating portion 4 having the shortest conductive path, and the non-embedded portion 8b of the heat generating portion 4 generates heat uniformly. . Also, in the electrode portions 3a and 3b, the current i flows through the non-embedded portion 8a of the electrode portions 3a and 3b and flows uniformly, so that local abnormal heat generation does not occur.

  Further, the nonwoven fabric constituting the base material 2 is rich in flexibility and stretchability, and the electrode portions 3a and 3b and the embedded portions 7a and 7b of the heat generating portion 4 are portions that are slightly inside from the surface of the base material 2. Therefore, the substrate 2 remains flexible and stretchable, and the planar heating element 1 retains flexibility and stretchability.

(Embodiment 2)
In FIG. 2, the sheet heating element 1 has electrode bodies 9a, 9b made of copper stranded wires fixed on a base material 2 made of nonwoven fabric by sewing thread sewing so as to cover the electrode bodies 9a, 9b. The heating element 4 is formed by laminating the resistor material 6 on the substrate 2. When laminating the resistor material 6, the resistor material 6 is melted and extruded into a film shape by a film forming extruder, placed on the surface of the substrate 2, and then pressed by a pressure roller. The embedded portion 7b is configured such that a part of the film is pushed into the substrate 2.

  In this embodiment, a copper stranded wire is used for the electrode bodies 9a and 9b. However, a stranded wire or a plated stranded wire of a copper alloy or an aluminum alloy, or these fine wires may be used. Furthermore, copper foil, aluminum foil, or the like may be formed by printing as in the first embodiment.

  The method of fixing the electrode bodies 9a and 9b is sewing thread sewing in this embodiment. However, depending on the form of the electrode bodies 9a and 9b, a method using an adhesive, the electrode bodies 9a and 9b are heated, Alternatively, a method may be used in which the fibers constituting the base material 2 are melted by pressurizing 2 and entangled with the electrode bodies 9a and 9b and fixed, or the electrode bodies 9a and 9b themselves are sewn to the base material 2.

  Next, the operation and action will be described.

  In FIG. 2, a part of the film of the resistor material 6 is pressed into the base material 2 so that a part of the film of the resistor material 6 is pressed by the pressure in the embedded portion 7b. Since the fibers are entangled with each other, when a mechanical stress such as bending or tension is applied, even if a force that separates the heat generating portion 4 made of the resistor material 6 from the base material 2 is applied, an anchor effect occurs and the heat generating portion 4 There is no peeling from the substrate 2.

  Moreover, the film thickness of the resistor material 6 extruded from the film forming extruder is uniform as a whole. This is because if the extruded film is partially thicker, only that part is heavier than the surrounding film, so the weight balance of the film is lost and the film is broken.

  Therefore, since the film of the resistor material 6 having a uniform film thickness is laminated on the substrate 2 and the whole is pressed uniformly, the surface of the heat generating part 4 made of the resistor material 6 becomes smoother, and the heat generating part 4 The thickness of the non-embedded portion 8b is also more uniform, and the heat generation uniformity of the heat generating portion 4 is improved.

(Embodiment 3)
In FIG. 3, the sheet heating element 1 is made of polyester resin, polyurethane resin, acrylic resin by flocking a base material 2a made of a resin film made of polyester resin, polyurethane resin, TPO resin or the like or a mixed resin thereof. The fiber 10 made of rayon resin or the like or a mixed resin thereof is planted on the substrate 2a and cut short to make the planted height constant. A conductive material 5 made of a silver paste is printed on the surface of the base material 2a on which the fibers 10 are flocked, and is thickly printed in the thickness direction beyond the height of the fibers 10 that are flocked, and then dried. 3a and 3b are configured. Further, the resistor material 6 is printed and dried between the electrode portions 3a and 3b while covering the entire surface or a part of the pair of electrode portions 3a and 3b, and the heat generating portion 4 is configured and electrically connected. State. The resistor material 6 constituting the heat generating portion 4 is also thickly printed and dried in the thickness direction beyond the height of the fiber 10 that is planted.

  Next, the operation and action will be described.

  In FIG. 3, when mechanical stress such as bending or tension is applied, a force is applied to separate the electrode portions 3 a and 3 b made of the conductive material 5 and the heat generating portion 4 made of the resistor material 6 from the base material 2. However, since the conductive material 5 constituting the electrode portions 3a and 3b and the resistor material 6 constituting the heat generating portion 4 are configured to hold the fibers 10 implanted in the base material 2, The anchor effect is generated, and the electrode portions 3a and 3b and the heat generating portion 4 are not peeled off from the base material 2.

  Further, since the implanted fibers 10 are cut to have a constant height, the portions above the fibers 10 of the electrode portions 3a and 3b and the heat generating portion 4 in the thickness direction are uniform in thickness and conductive. Since the density of the material 5 and the resistor material 6 is also uniform, the current i flows uniformly in the part above the fiber 10 of the heat generating part 4 where the conduction path is shortest, and from the fiber 10 of the heat generating part 4 The upper part will generate heat uniformly. Also, in the electrode portions 3a and 3b, the current i flows through the portion of the electrode portions 3a and 3b above the fiber 10 and flows uniformly, so that local abnormal heat generation does not occur.

  As described above, the planar heating element according to the present invention has an electrode portion and a resistor material made of a conductive material even when mechanical stress such as bending or tension is applied while maintaining flexibility and stretchability. The heat generating part made of is not peeled off from the base material, there is no abnormal heat generation of the electrode part, and the heat generating part can ensure uniform heat generation, so that the load is applied to the electric carpet or vehicle seat that is applied to the heating element It is useful as a heating product such as a heater.

DESCRIPTION OF SYMBOLS 1,11 Planar heating element 2, 2a, 22 Base material 3a, 3b Electrode part 4 Heat generating part 5 Conductive material 6 Resistor material 7a, 7b Embedded part 8a, 8b Non-embedded part 9a, 9b Electrode body 10, 31 Fiber 12 Base Material 13 Comb Electrode 14 Polymer Resistor 15 Coating Material 20 Surface Material 30 Void

Claims (3)

From a base material having flexibility and stretchability, a pair of electrode parts made of a conductive material on the surface of the base material, and a resistor material having a self-temperature control function electrically connected to the pair of electrode parts A heating element that is formed by applying the resistor material to the substrate, pressurizing it, and partially embedding it in the substrate in the thickness direction. The planar heating element according to claim 1, wherein the substrate is made of a resin film, and fibers are implanted on the surface thereof by flocking. The planar heating element according to claim 1, wherein the substrate is made of a fiber such as a woven fabric, a knitted fabric, or a non-woven fabric, and is provided with fiber fluff on the surface thereof.