JP2009181732A - Sheet heating element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stable-performance sheet heating element that cuts off a flow of an overcurrent without being provided with extra equipment for cutting off an overcurrent. <P>SOLUTION: In the sheet heating element is provided with: two long rectangular-shaped main electrodes 3a (3b) formed on an electrically insulating substrate by screen printing to be parallel to each other; a plurality of branch electrodes 3c (3d) extending from the main electrodes 3a (3b), respectively, toward the other main electrode to form a comb-like form; a polymer resistor 4 formed by screen printing to cover the top surfaces of the plurality of branch electrodes 3c (3d); and furthermore, an electrically insulating coating material 5 covering the top surface of the polymer resistor 4. Part of the shorter one of the main electrodes 3a (3b) is formed to be narrow. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a planar heating element that is disposed on a floor surface of a living space and warms the entire floor surface.

  3 is a perspective view of a main part of a conventional sheet heating element having PTC characteristics, FIG. 4 is a plan transparent view of the sheet heating element of the related art, and FIG. 5 is an XY cross section of the sheet heating element of the related art. FIG.

  As shown in FIG. 3, a conventional sheet heating element 11 includes a pair of a positive electrode and a negative electrode obtained by printing and drying a conductive paste on an upper surface of an electrically insulating base material 12 such as a polyester sheet. Main electrodes 13a and 13b are arranged in parallel. As shown in FIG. 4, the main electrodes 13a and 13b have a rectangular shape with long sides in one direction, and the other main electrodes facing each other from the long sides of the main electrodes 13a and 13b. A plurality of branch electrodes 13c and 13d extend in the direction (from 13a to 13b or from 13b to 13a).

  As shown in FIG. 4, a polymer resistor 14 obtained by printing and drying polymer resistor ink is provided on the upper surfaces of the branch electrodes 13c and 13d. The polymer resistor 14 is configured by dispersing a base polymer and a conductive material such as carbon black, metal powder, and graphite in a solvent, and in particular, a polymer resin having a PTC characteristic using a crystalline resin as a base polymer. (For example, see Patent Documents 1, 2, and 3).

  The polymer resistor 14 is supplied with power from a large number of branch electrodes 13c and 13d, and generates heat when a current flows. Note that the PTC characteristic (an acronym for English Positive Temperature Coefficient which means that the resistance has a positive temperature coefficient) is a resistance temperature characteristic in which the resistance value increases as the temperature rises, and the resistance value increases rapidly when reaching a certain temperature. The polymer resistor 14 having PTC characteristics can provide a planar heating element having a self-temperature adjusting function.

Further, the upper surface of the main electrodes 13a and 13b, the branch electrodes 13c and 13d, and the polymer resistor 14 is covered and protected with a covering material 15 made of the same material as that of the substrate 12. When using a polyester film as the base material 12 and the covering material 15, for example, a polyethylene-based heat-fusible resin (not shown) is bonded to the covering material 15 in advance, and pressurizing while applying heat (heat The base material 112 and the covering material 15 are joined via a heat-fusible resin.
Japanese Patent Laid-Open No. 56-13689 JP-A-6-96843 JP-A-8-120182

  However, in the conventional sheet heating element, an unsafe accident due to product deterioration occurs due to long-term use, and one of the unsafe accidents is ignition. There are various causes of ignition. One of the causes is that excessive current flows to generate heat and lead to ignition.

The conventional sheet heating element is not equipped with a means to cut off the excessive current, and only the earth leakage breaker that is installed at the time of construction is provided, but the sheet shape like a heater for floor heating that warms the entire floor surface In many cases, multiple heating elements are installed according to the floor area to be constructed, and since a large capacity earth leakage breaker is used, it may not be possible to handle only a part of the planar heating element through which excessive current flows. is there.

  On the other hand, in order to deal with a part of the planar heating elements, it is necessary to provide each of the planar heating elements with an earth leakage breaker or a current fuse. It was.

  An object of the present invention is to solve the above-described conventional problems, and to provide a planar heating element that blocks the flow of an excessive current and has a stable quality without specially mounting a device that blocks the excessive current. And

  In order to solve the above-described conventional problems, the planar heating element of the present invention includes two elongated rectangular main electrodes formed by screen printing on a base material having electrical insulation and arranged side by side. A plurality of branch electrodes extend in a comb shape from the main electrode toward the other main electrode, and an upper surface of the plurality of branch electrodes is covered with a polymer resistor formed by screen printing. In the planar heating element in which the upper surface of the polymer resistor is covered with a coating material having electrical insulation, a part of the short width of the main electrode is narrowed, so that the coating material can be used by long-term use of the planar heating element. Even if water or foreign matter enters due to deterioration, scratches, peeling, etc., and an overcurrent occurs due to a short circuit, the part where the width of the shorter part of the main electrode is narrowed serves as a foil fuse to overload the current. Since it can be shut off, ignition due to abnormal heat generation It is possible to prevent.

  The planar heating element of the present invention can provide a planar heating element with stable quality by blocking the flow of the excessive current without specially mounting a device that blocks the excessive current.

  A planar heating element according to a first aspect of the present invention comprises two elongated rectangular main electrodes formed by screen printing on a substrate having electrical insulation and arranged side by side, and the other main electrode. A plurality of branch electrodes extend in a comb shape in the direction of the electrodes, and the upper surfaces of the plurality of branch electrodes are covered with a polymer resistor formed by screen printing, and the upper surface of the polymer resistor is further covered In a planar heating element covered with a coating material having electrical insulation, a part of the shorter width of the main electrode is narrowed, so that the coating material is deteriorated, damaged, peeled off by long-term use of the planar heating element, etc. Even if water or foreign matter enters and causes an overcurrent due to a short circuit, the part where the shorter width of the main electrode is narrowed can act as a foil fuse to block the overcurrent, so abnormal heating Can prevent ignition by

  Further, since the electrical connection portion as in the current fuse configuration is not configured and the fuse function can be provided with the same thickness as the main electrode, the safety can be increased and the configuration can be reduced.

  In addition, since the main electrode is disposed on a base material having electrical insulation, and further, a covering material having electrical insulation is covered so as to be in close contact with the main electrode. The main electrode is not heated by heat conduction to the insulating base material and the covering material, and is melted only when an instantaneous excessive current flows.

  In the planar heating element of the second invention, in particular in the first invention, the electrode is formed by printing a conductive resin paste, so that the narrow part of the main electrode is melted at a lower temperature. It is configured. Therefore, since it is the structure which interrupts | blocks rapidly and reliably with respect to an overcurrent, it has become the structure where safety | security improved further.

  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 are schematic configuration diagrams of a planar heating element according to Embodiments 1 and 2 of the present invention. FIG. 1 is a perspective view of a main part, and FIG. 2 is a plan view of the main part.

  In FIG. 1, a sheet heating element 1 is a pair (electrically positive side and negative side) formed by printing and drying a silver paste on the upper surface of a thin roll-shaped electrically insulating substrate 2 such as a polyester film. An electrode 3 and a polymer resistor 4 as a polymer resistor formed by printing and drying a polymer resistor ink so as to overlap the electrode 3 are provided.

  A thin-walled polyester film or the like formed in advance with an adhesive resin layer (not shown) such as an acrylic adhesive having adhesiveness with the electrode 3, the polymer resistor 4, and the electrically insulating substrate 2. The sheet heating element 1 is formed by bonding the electrically insulating coating material 5 together.

  The electrode 3 has a pair of elongated rectangular main electrodes 3 a and 3 b (corresponding to the positive side and the negative side of the DC power supply) so as to face each other, and the main electrodes 3 a and 3 b are formed of the planar heating element 1. It is disposed along the outer side in the longitudinal direction.

  A plurality of branch electrodes 3c and 3d are led out alternately from the main electrodes 3a and 3b toward the main electrode on the other side to form a comb shape as a whole, and the polymer arranged so as to overlap therewith By supplying power to the resistor 4 from a large number of branch electrodes 3c and 3d, a current flows through the polymer resistor 4 to generate heat. Power supply wirings 6a and 6b are soldered to the welded copper foil terminals (not shown) on the main electrodes 3a and 3b and connected to a power source.

  In the vicinity of the power feeding portion of the main electrodes 3a and 3b, a portion where a part of the short width of the main electrodes 3a and 3b is narrowed is provided, and a narrow electrode 3e having a narrow width is formed. The arranged narrow electrode 3e is configured not to be disconnected by a current during normal use but to have a cross-sectional area that is melted by an excessive current generated at the time of a short circuit. Therefore, it has the same effect as a so-called foil fuse.

  Moreover, since the site | part where the electric current of the planar heating element in this invention becomes the maximum is a power supply part, the narrow electrode 3e is arrange | positioned in the power supply part vicinity so that it may work effectively. In addition, the narrow electrode 3e disposed in a part of the main electrodes 3a and 3b is disposed by screen printing, so that a function capable of interrupting an excessive current without requiring parts such as a current fuse or a leakage breaker is provided. In addition, an electrical connection portion such as a current fuse configuration is not configured, and the thickness can be set to the same thickness as the main electrode. Therefore, there is no fear of disconnection due to long-term vibration of the floor and the like, and it can be made thin while improving safety.

  Further, the main electrodes 3a, 3b and the narrow electrode 3e are disposed on the electrically insulating substrate 2, and the covering material 5 is in close contact so as to cover the main electrodes 3a, 3b and the narrow electrode 3e. In use, the narrow electrode 3e is not overheated due to heat conduction to the electrically insulating base material 2 and the covering material 5, and when an instantaneous excessive current flows, the electrically insulating base material 2 and the covering material Since the material 5 uses an electrically insulating base material such as a polyester film, heat cannot be dissipated instantaneously, and the material 5 is quickly melted. Therefore, it is incorporated in a floor panel and used as a heater for floor heating.

  Further, by disposing the narrow electrode 3e in the vicinity of the power feeding portion, the narrow electrode 3e and the power feeding portion are covered with a nonflammable material such as aluminum tape or glass cloth tape, thereby further improving the safety against ignition. Can do.

(Embodiment 2)
Since the shape of the planar heating element of the second embodiment is the same as that of the planar heating element of the first embodiment, it will be described with the same drawing.

  The planar heating element of the second embodiment is arranged by printing and drying the main electrodes 3a and 3b in the first embodiment with a conductive resin paste, and the narrow electrode 3e is melted at a lower temperature. It is configured as follows. Therefore, since it is the structure which interrupts | blocks rapidly and reliably with respect to an overcurrent, it has become the structure where safety | security improved further.

  Regarding the arrangement of these narrow electrodes, a screen printing plate different from the main electrode may be used to reduce the thickness and reduce the cross-sectional area. Any configuration may be used as long as the object of the invention can be achieved.

  As described above, the planar heating element according to the present invention can be configured as a thin and long planar heating element while being equipped with a means for interrupting excessive current due to a short circuit, and is arranged on the floor. It can be used for heaters that are installed and warm the entire floor, and other appliances that require heating.

The principal part perspective view which shows the planar heating element in Embodiment 1 and Embodiment 2 of this invention The principal part top view of the planar heating element in Embodiment 1 and Embodiment 2 Main part perspective view of conventional planar heating element Main part plan view of a conventional sheet heating element Schematic configuration cross-sectional view of a conventional planar heating element

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Planar heating element 2 Electrically insulating base material 3 Electrode 3a, 3b Main electrode 3c, 3d Branch electrode 3e Narrow electrode 4 Polymer resistor 5 Coating material 6 Power supply wiring

Claims (2)

Two long rectangular main electrodes formed by screen printing on a substrate having electrical insulation and arranged side by side, and a plurality of comb electrodes from each main electrode toward the other main electrode A planar shape in which the branch electrode extends, the upper surface of the plurality of branch electrodes is covered with a polymer resistor formed by screen printing, and the upper surface of the polymer resistor is covered with a coating material having electrical insulation. A planar heating element characterized in that a part of the short width of the main electrode is narrowed in the heating element. The planar heating element according to claim 1, wherein the electrode is formed by printing a conductive resin paste.

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