JP2000340341A - Flexible sheet heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet heater having sufficient flexibility capable of generating heat at a low voltage. SOLUTION: A flexible insulating sheet 4 has plural holes, a little smaller heating element 2 than the hole is embedded in the hole, the both surfaces of the insulating sheet 4 are covered by an electrode sheet comprising a metal net and the both surfaces of each element are integrally glued to the electrode sheet, in order to structure this flexible sheet heater 1. It can be also structured by covering both surfaces of plural heating elements 2 arranged at a designated interval by the electrode sheet comprising the metal net and integrally gluing each heating element 2 to the electrode sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible sheet heating element which can be bent freely without heat generation unevenness over the entire sheet surface.

[0002]

2. Description of the Related Art Conventionally, planar heating elements have been used in various places. For example, as shown in FIG. 3 (a), a copper foil or an aluminum foil is adhered to a sheet-like heating element 2 in which carbon black is mixed with a silicone rubber composition with a conductive adhesive, and both sides of the heating element 2 are bonded. There is a configuration in which electrodes 3a and 3b are mounted (Japanese Patent Laid-Open No. 50-43494)
JP, JP-A-50-150039). This configuration does not require a high applied voltage because the thickness of the heating element is small and the distance between the electrodes is small, but when folded, as shown in FIG. Since the sheet is adhered over the entire surface, a resistance against bending as shown by an arrow acts on the sheet heating element 1 and the sheet cannot be bent flexibly.

Further, as shown in FIG. 4, there is a sheet heating element 2 in which metal powder and carbon fiber are mixed with silicone rubber, and long electrodes 3a, 3b are buried in parallel at both ends. (See JP-A-6-231869). This configuration requires a high applied voltage of about 100 V, for example, when used for a heat retaining plate because the distance between the electrodes is large and the resistance between the electrodes is large. Also,
Because of the parallel electrodes, the shape of the heating element was limited to a square shape.

[0004]

As a countermeasure against this, FIG.
Although a flexible metal net or a metal-deposited fiber was used for the electrode of the sheet heating element, sufficient flexibility was not obtained because the electrode and the heating element 2 were adhered over the entire sheet surface. Was. The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a sheet heating element having sufficient flexibility and capable of generating heat at a low voltage.

[0005]

In the flexible planar heating element of the present invention, a heating element slightly smaller than the hole is embedded in a plurality of holes of a flexible insulating sheet. It is characterized in that both sides are covered with an electrode sheet made of a metal mesh, and both sides of each heating element are bonded and integrated with the electrode sheet. Since the heating element embedded in the hole of the insulating sheet is bonded to the electrode sheet, the flexibility of this portion is low, but the insulating sheet is not bonded to the electrode sheet and is embedded in this hole. Since there is some clearance between the heating element and the heating element, the insulating sheet portion has flexibility and can be bent freely.

The shape of the hole in the insulating sheet in which the heating element is embedded is arbitrary, and may be a circle, a rectangle, a long rectangle, or the like. In the case of a circle or a rectangle, it can be bent flexibly in any direction. In the case of a long rectangle, it can be flexibly bent only in a direction perpendicular to this, and it is particularly suitable for a case where it is wound around a column and heated. Also, a configuration in which a plurality of heating elements arranged at predetermined intervals are covered with an electrode sheet made of a metal net without using an insulating sheet, and each heating element and the electrode sheet are bonded and integrated. It can also be. The interval between the heating elements is within twice the thickness of the heating elements. If it exceeds this, a short circuit is likely to occur.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. Various rubbers can be used for the base of the heating element used for the flexible planar heating element of the present invention. For example, in addition to natural rubber, silicone rubber, urethane rubber,
Synthetic rubbers such as polybutadiene rubber, SBR rubber, NBR rubber, EP rubber and EPT rubber are exemplified. in particular,
Silicone rubber is preferred in terms of durability and flexibility. The heating element is obtained by adding a conductive powder to these unvulcanized rubbers, mixing them uniformly, forming them into a sheet, and then vulcanizing them. Thereafter, the heating element is subjected to blanking. The punching process may be performed so that a desired shape or pattern is obtained, and the punching shape is arbitrary such as a rectangle, a circle, an ellipse, or a pattern.

As the conductive powder, carbon black,
Fine particles such as graphite and metal can be used. Powders of copper, gold, silver, platinum, aluminum, iron, nickel and the like can be used for the metal particles. In addition, those obtained by adding finely cut carbon fibers to these can also be used.

As the electrodes bonded to the upper and lower surfaces of the sheet-like heating element, a net made of a thin metal wire such as copper having high conductivity is used. Such a metal mesh electrode is adhered to the upper and lower surfaces of the sheet-shaped heating element subjected to the punching process, whereby a flexible sheet heating element is obtained. The flexible sheet heating element of the present invention has excellent flexibility and can generate heat at a low voltage. For example,
In the case of a planar heating element having an area of 25 cm ² and a heating element thickness of 1 mm, it takes about 3 batteries with two D-size alkaline batteries (3 V).
It can generate heat at 5 ° C. (room temperature 20 ° C.) for 13 hours. For this reason, it can be suitably used for the heat insulation of the human body such as winter clothing, winter shoes, etc., the insulation of seats, and various curved surfaces that require heat insulation and heating.

[0010]

(Embodiment 1) FIG. 1 shows a flexible sheet heating element of the present invention. FIG. 1A is a plan view showing an example of the flexible planar heating element of the present invention, and FIG. 1B is a cross-sectional view of FIG. The heating element 2 is embedded in a large number of rectangular holes formed by punching with some clearance 6 over the entire surface of the flexible insulating sheet 4. Electrode sheets 3a and 3b made of a metal net are bonded and integrated on the upper and lower surfaces of the base 2 with an adhesive.
The planar heating element 1 manufactured in this manner has a clearance 6 between itself and the heating element 2 because the flexible insulating sheet 4 is not bonded to the electrode sheets 3a and 3b. It can be bent freely and is extremely flexible.

(Embodiment 2) The sheet heating element 1 of this embodiment is
As shown in FIG. 2, the long heating elements 2 are alternately arranged in parallel with the long insulating material 7 in parallel with each other. Adhered and integrated. In this planar heating element 1, the long insulating material 7 is not bonded to the electrode sheets 3a and 3b,
Further, since there is a clearance 6 between the heating element 2 and the heating element 2, the insulating material 7 can be flexibly bent along the heating element at the portion of the insulating material 7, and is particularly suitable for a case of being wound around a column and heated. .

[0012]

As described above, the flexible planar heating element of the present invention can be bent freely and can uniformly generate heat at a low voltage by adopting the above-mentioned structure.

[Brief description of the drawings]

FIG. 1 shows a flexible planar heating element of the present invention, wherein the upper part is a plan view and the lower part is a sectional view.

FIG. 2 shows a flexible planar heating element of the present invention in a mode different from that of FIG. 1, wherein the upper part is a plan view and the lower part is a cross-sectional view.

FIG. 3 shows a conventional planar heating element, wherein (a) is a perspective view,
(A) is sectional drawing.

FIG. 4 is a perspective view showing a conventional planar heating element in a mode different from that of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Planar heating element 2 ... Heating element 3a, 3b ... Electrode 4 ... Insulating sheet 5 ... Adhesive

Continued on the front page F term (reference) 3K034 AA02 AA05 AA06 AA08 AA09 AA15 AA16 AA24 AA28 AA32 BB19 BC15 CA02 CA11 CA13 CA26 CA33 HA04 HA05 JA01 JA09

Claims (2)

[Claims] 1. A heating element slightly smaller than this hole is embedded in a plurality of holes of a flexible insulating sheet, and both sides of the insulating sheet are covered with an electrode sheet made of a metal net. A flexible sheet heating element characterized in that both sides are bonded and integrated with an electrode sheet. 2. A plurality of heating elements arranged at predetermined intervals are covered on both sides with an electrode sheet made of a metal mesh, and each heating element and the electrode sheet are bonded and integrated. A flexible planar heating element characterized by the following.