JP2008147110A - Heating element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating element without losing merits of processability, moldability and a lightweight property of resin, and suitable for long-term reliability as well. <P>SOLUTION: The heating element 1 is provided with a pair of electrodes 4 due to be pinched by a base side resin film 2 and a cover side resin film 3, and a polymer resistor body 5 formed between the pair of the electrodes, and at least one of the base side resin film 2 or the cover side resin film 3 consists an inorganic oxide. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heating element that can be used as a heat source for heating, heating, drying, and the like, and particularly relates to a heating element that has excellent reliability during long-term use.

  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 heating element (which means an abbreviation of English Positive Temperature Coefficient which means a positive resistance temperature characteristic) using a combination of a conductive material and a resin is used, a temperature control circuit is used. It is known as a device with advantages such that it becomes unnecessary and the number of parts can be reduced.

  As shown in FIG. 5, these structures are obtained by printing or applying a conductive ink composition on a base material 42 having a function as a casing structure, such as a ceramic or an insulating metal plate. 44 and a resistor 45 obtained by printing or applying a resistor ink composition at a position where power is supplied, and a heating element 41 is formed from the electrode 44 and a cover material 43 covering the resistor 45. . Fig.5 (a) is a top view of a heat generating body, FIG.5 (b) is xy position sectional drawing of Fig.5 (a). Since the comb-shaped electrode 44 and the resistor 45 are isolated from the outside by the base material 42 and the cover material 43, long-term reliability is imparted.

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

  Recently, polyester-based resin films typified by polyethylene terephthalate are often used as base materials and cover materials. This is because there are many points that should be satisfied in terms of cost, workability, formability, and lightness.

  However, in many cases, moisture deterioration and oxidation deterioration are not sufficient as compared with a base material or cover material made of metal or ceramic. Although it is a level that has almost no problem with durability at the level of several years, it should be a material that can ensure long-term reliability of 10 years or more when used for applications that require on-site construction together with, for example, building materials Is desirable.

  The present invention aims to provide a heating element suitable for long-term reliability without impairing the merit of processability, moldability, and lightness of the resin, and serves to protect the electrode and the resistor. The purpose is to make it more effective by examining the material of the resin film.

  The heating element of the present invention for solving the conventional problems includes a pair of electrodes sandwiched between a base-side resin film and a cover-side resin film, and a polymer resistor formed between the pair of electrodes. And at least one of the base-side resin film and the cover-side resin film contains an inorganic oxide.

  The above-described configuration is characterized by having long-term stability exhibited by metals, ceramics, and the like without impairing merits such as low cost, easy processability, easy moldability, and lightness of the resin.

  Although it does not specifically limit in this invention, it becomes especially effective for the heat generating body which requires long-term durability, such as a floor heating apparatus.

  As a method for producing a film containing an inorganic oxide, raw materials having respective inherent shapes of a resin and an inorganic oxide are kneaded in advance and integrated into a sheet or film by a T-die method, an inflation method, a roll method, or the like. A method of creating a processed material, a method of pasting a film-like inorganic oxide separately prepared on a film that has already been completed, and various processing methods such as coating and vapor deposition of inorganic oxide on a resin film For example, the surface of the film may be modified. Moreover, the film obtained by the said method may be a film which consists of a multilayer which laminated | stacked on the layer form further. At this time, the film composed of a plurality of layers may be composed of only the same resin depending on the required performance, and different resins may be used for the purpose of expressing different functions depending on the layer.

  The heating element of the present invention can suppress moisture deterioration and oxidation deterioration by containing an inorganic oxide in a resin film, and can provide a device excellent in workability, moldability, and long-term reliability. Become.

  A first invention includes a pair of electrodes sandwiched between a base side resin film and a cover side resin film, and a polymer resistor formed between the pair of electrodes, the base side resin film, At least one of the cover-side resin films contains an inorganic oxide, and a heating element having excellent long-term reliability can be provided. For example, examples of the inorganic oxide include aluminum oxide, silicon oxide, titanium oxide, and zircon oxide.

  In the second invention, the base-side resin film and the cover-side resin film contain a polyester-based film as a main component. A material can be obtained.

  According to a third invention, in any one of the first and second heating elements, the polyester film is either a polyethylene terephthalate resin or a polybutylene terephthalate resin, and is heat resistant, mass-productive, and relatively inexpensive. Can provide a heating element.

  In a fourth aspect of the invention, in particular, in the heating element of any one of the first to third aspects, the inorganic oxide is either aluminum oxide or silicon oxide, and the base side resin film and the cover side resin film are By containing it in at least one of them, it is possible to provide an excellent base material with very little oxidation deterioration and moisture deterioration.

  In the case of resin alone, oxygen and moisture are dissolved and diffused according to the crystallinity of the resin and the degree of thermal fluctuation, whereas oxygen oxide filler is kneaded and dispersed. And the diffusion of moisture is further hindered, making it difficult to permeate easily, and as a result, an oxidation resistant and water resistant film can be obtained.

According to a fifth aspect of the invention, in particular, in the heating element of any one of the first to fourth aspects, at least one of the base-side resin film surface or the cover-side resin film surface on the side not in contact with the electrode and the resistor is inorganic. A heating element obtained by depositing an oxide, and a highly durable base material can be obtained by applying a thin deposition film made of an inorganic oxide on one side of the film surface. Can provide.

  According to a sixth aspect of the present invention, in the heating element of any one of the first to fifth aspects of the invention, an adhesive layer made of a copolyester resin is provided on the surface of the cover side resin film that covers the electrode and the resistor. By providing a new adhesive layer between the cover-side resin film and the base-side resin film, the adhesion performance can be improved, and it can function as an effective barrier layer against oxygen and moisture.

  The seventh invention is particularly excellent in reproducibility and mass productivity in the heating element of any one of the first to sixth inventions, in which the electrode and the resistor on the base side resin film are formed by a printing method. A heating element is obtained.

  According to an eighth invention, in particular, in the heating element according to any one of the first to seventh inventions, the member constituting the electrode includes at least conductive fine particles and a copolymerized polyester resin, and has heat resistance and impact resistance. And good printing characteristics can be obtained.

  According to a ninth invention, in particular, in the heating element according to any one of the first to eighth inventions, the member constituting the resistor includes at least carbon and an elastomer component or a rubber component, and has good heat resistance. In addition, a heating element excellent in printability and mass productivity can be provided.

  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)
FIG. 1A is a plan view of a heating element according to Embodiment 1 of the present invention, and FIG. 1B is a cross-sectional view taken along line xy in FIG.

  In FIG. 1, the structure of the heating element 1 is as follows. A base-side resin film 2 was prepared by uniformly dispersing a layered silicate inorganic crystal and a compatibilizing agent in polyethylene terephthalate (PET), and was formed into a film having a thickness of 150 μm. The weight of layered silicate relative to PET was 3%.

  A silver paste made of silver fine particles and a copolyester resin was printed on the base-side resin film 2 formed as a composite film made of PET and an inorganic oxide, and then dried to obtain a pair of comb-shaped electrodes 4. Further, a polymer resistor ink was printed at a position where power was supplied by the electrode 4, and a polymer resistor 5 was produced by subsequent drying. The polymer resistor has a PTC characteristic and is produced so that the exothermic saturation temperature at the time of heat retention is about 65 ° C. The polymer resistor ink was produced by kneading and crosslinking an ethylene vinyl acetate copolymer and carbon black into an ink with a solvent using acrylonitrile butyl rubber as a binder.

  The cover-side resin film 3 was the same as the base-side resin film 2, and was bonded to the electrode 4 and the polymer resistor 5 described above, and the outer peripheral portion was sealed to produce the heating element 1.

  It was found that the heating element thus obtained has high durability of the cover-side resin film and the base-side resin film, and exhibits good barrier resistance against oxygen and moisture from the outside.

(Embodiment 2)
FIG. 2A is a plan view of a heating element according to Embodiment 2 of the present invention, and FIG.
It is sectional drawing of a -y line.

  In FIG. 2, the structure of the heating element 11 is as follows. A base-side resin film 12 in which alumina oxide was uniformly dispersed in polybutylene terephthalate (PBT) was prepared and made into a film having a thickness of 150 μm. The weight of alumina oxide relative to PBT was 2%.

  A silver paste made of silver fine particles and a copolyester resin was printed on the base-side resin film 12 formed as a composite film made of PBT and an inorganic oxide, and then dried to obtain a pair of comb-shaped electrodes 4. Further, a polymer resistor ink was printed at a position where power was supplied by the electrode 4, and a polymer resistor 5 was produced by subsequent drying. The polymer resistor has a PTC characteristic and is produced so that the exothermic saturation temperature at the time of heat retention is about 65 ° C. The polymer resistor ink was produced by kneading and crosslinking an ethylene vinyl acetate copolymer and carbon black into an ink with a solvent using acrylonitrile butyl rubber as a binder.

  The cover-side resin film 13 is the same as the base-side resin film 12, and a hot-melt type adhesive layer 6 made of a copolymerized polyester resin is provided on one side of the 13 so that the above-described electrode 4 and the high-side resin film 13 are formed. The heat generating element 11 was prepared by bonding so as to adhere to the molecular resistor 5.

  In the heating element thus obtained, the polymer resistor 5 serving as a heating part is protected by the cover-side resin film and the base-side resin film having a high barrier property, and further through an adhesive layer, It was found that the film exhibited good barrier resistance against external oxygen and moisture.

(Embodiment 3)
FIG. 3A is a plan view of a heating element according to Embodiment 3 of the present invention, and FIG. 3B is a cross-sectional view taken along line xy in FIG.

  In FIG. 3, the structure of the heating element 21 is as follows. As the base-side resin film 22, a polyethylene terephthalate (PET) film having a thickness of 150 μm and aluminum oxide deposited thereon was prepared.

  Next, a silver paste composed of silver fine particles and a copolyester resin was printed on the base-side resin film 22 and then dried to obtain a pair of comb-shaped electrodes 4. Further, a polymer resistor ink was printed at a position where power was supplied by the electrode 4, and a polymer resistor 5 was produced by subsequent drying. The polymer resistor has a PTC characteristic and is produced so that the exothermic saturation temperature at the time of heat retention is about 65 ° C. The polymer resistor ink was produced by kneading and crosslinking an ethylene vinyl acetate copolymer and carbon black into an ink with a solvent using acrylonitrile butyl rubber as a binder.

  The cover-side resin film 23 used was the same as the base-side resin film 22, and was bonded to the electrode 4 and the polymer resistor 5 described above, and the outer peripheral portion was sealed to create the heating element 21.

  It was found that the heating element thus obtained has high durability of the cover-side resin film and the base-side resin film, and exhibits good barrier resistance against oxygen and moisture from the outside.

(Embodiment 4)
FIG. 4A is a plan view of a heating element according to Embodiment 4 of the present invention, and FIG.
It is sectional drawing of a -y line.

  In FIG. 4, the structure of the heating element 31 is as follows. As the base-side resin film 32, a polyethylene terephthalate (PET) film having a thickness of 150 μm deposited with silica (silicon oxide) was prepared.

  Next, a silver paste composed of silver fine particles and a copolyester resin was printed on the base-side resin film 32, and a pair of comb-shaped electrodes 4 was obtained by subsequent drying. Further, a polymer resistor ink was printed at a position where power was supplied by the electrode 4, and a polymer resistor 5 was produced by subsequent drying. The polymer resistor has a PTC characteristic and is produced so that the exothermic saturation temperature at the time of heat retention is about 65 ° C. The polymer resistor ink was produced by kneading and crosslinking an ethylene vinyl acetate copolymer and carbon black into an ink with a solvent using acrylonitrile butyl rubber as a binder.

  The cover-side resin film 33 is the same as the base-side resin film 32, and a hot-melt adhesive layer 6 made of a copolyester resin is provided on the surface of the side 33 where no silicon oxide is deposited, A heating element 31 was prepared by bonding the electrodes 4 and the polymer resistor 5 so that they were adhered to each other.

  In the heating element thus obtained, the polymer resistor 5 serving as a heating part is protected by the cover-side resin film and the base-side resin film having a high barrier property, and further through an adhesive layer, It was found that the film exhibited good barrier resistance against external oxygen and moisture.

  As described above, since the heating element in the present invention can provide a highly durable heating element, it exhibits long-term stability for applications involving construction such as floor heating appliances. It is excellent in mass productivity and can demonstrate cost merit.

(A) Top view which shows the structure of the heat generating body in Embodiment 1 of this invention (b) Sectional drawing of the heat generating body (A) Top view which shows the structure of the heat generating body in Embodiment 2 of this invention (b) Sectional drawing of the heat generating body (A) Top view which shows the structure of the heat generating body in Embodiment 3 of this invention (b) Sectional drawing of the heat generating body (A) Top view which shows the structure of the heat generating body in Embodiment 4 of this invention (b) Sectional drawing of the heat generating body (A) Plan view showing a conventional heating element (b) Cross-sectional view of the heating element

Explanation of symbols

1, 11, 21, 31, 41 Heating element 2, 12, 22, 32 Base side resin film 3, 13, 23, 33 Cover side resin film 4 Electrode 5 Polymer resistor 6 Adhesive layer 42 Base material 43 Cover material 44 Electrode 45 Resistor

Claims (9)

A pair of electrodes sandwiched between the base-side resin film and the cover-side resin film, and a polymer resistor formed between the pair of electrodes, at least of the base-side resin film and the cover-side resin film One is a heating element containing an inorganic oxide. The heating element according to claim 1, wherein the base-side resin film and the cover-side resin film include a polyester film as a main component. The heating element according to claim 2, wherein the polyester film is one of polyethylene terephthalate resin or polybutylene terephthalate resin. The heating element according to any one of claims 1 to 3, wherein the inorganic oxide is either aluminum oxide or silicon oxide. The heating element according to any one of claims 1 to 4, wherein an inorganic oxide is vapor-deposited on at least one of a base-side resin film surface or a cover-side resin film surface that is not in contact with the electrode and the resistor. The heating element according to any one of claims 1 to 5, wherein an adhesive layer made of a copolyester resin is provided on a surface of the cover-side resin film that covers the electrode and the resistor. The heating element according to any one of claims 1 to 6, wherein the electrode and the resistor on the base-side resin film are formed by a printing method. The heating element according to any one of claims 1 to 7, wherein the member constituting the electrode includes at least conductive fine particles and a copolyester resin. The heating element according to any one of claims 1 to 8, wherein the member constituting the resistor includes at least carbon and an elastomer component or a rubber component.