JP2000150118A - Flat heater and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a that heater having low power consumption due to its capability of generating heat at a low voltage, manufacturable at a low cost, and its manufacturing method. SOLUTION: Many holes 14 passing through a flexible insulating sheet material 13 in its thickness direction are provided, a heating material 11 comprising a mixture of an insulating matrix material and conductive powder is filled in these holes 14, and electrodes 12a, 12b to be connected to the end surface of the heating material 11 are disposed on the upper and lower surfaces of the insulating sheet material 13 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet heating element and a method for manufacturing the same, and more particularly, to a method for consuming less power.
Further, the present invention relates to a planar heating element which can be manufactured at low cost and a method for manufacturing the same.

[0002]

2. Description of the Related Art Hitherto, as a heating element embedded in a heat insulation jacket, there has been proposed a heating element in which a nichrome wire is embedded in a meandering state in a cloth, and a voltage is applied to both ends of the nichrome wire using a battery or the like as a power source. ing. However, the heating of the nichrome wire requires a large amount of electric power, so that the battery is consumed at an early stage, and a large or large number of batteries are required to make up for it. FIG. 4 shows a planar heating element that uniformly generates heat in a planar heating portion.
The following are known. This sheet heating element 1 forms a sheet-like heating section 2 from a mixture of carbon particles and a synthetic resin, and an electrode 3 is formed along both edges of the heating section 2.
a, 3b are buried, and a voltage is applied between the electrodes 3a, 3b to cause the heat generating portion 2 to generate heat.

However, in such a conventional planar heating element 1, since the distance between the electrodes 3a and 3b is large, it is necessary to apply a relatively high voltage for heat generation. Therefore, not only does the power consumption increase, but also it is necessary to cover the upper and lower surfaces of the heating section 2 with an insulating material to prevent electric shock.
There was a problem that running cost and manufacturing cost increased.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet heating element which consumes less power and can be manufactured at low cost, and a method for manufacturing the same.

[0005]

According to a planar heating element of the present invention for solving the above-mentioned problems, a flexible insulating sheet material is provided with a large number of holes penetrating in a thickness direction, and these holes are provided with an insulating matrix. A heating material made of a mixture of a material and conductive powder is filled, and electrodes connected to end surfaces of the heating material are arranged on both upper and lower surfaces of the insulating sheet material.

In the planar heating element of the present invention, a large number of heating elements composed of a mixture of an insulating matrix material and a conductive powder are distributed in a spot shape at intervals on a flexible insulating sheet material. Then, a voltage is applied between the electrodes arranged on both the upper and lower surfaces in the thickness direction of each of these heat generating materials to generate heat. As described above, since the distance between the electrodes is extremely close, the heating element sufficiently generates heat even when the applied voltage is low, and the heating material is distributed in a spot-like coarse state. Electric power can be reduced. In addition, since the applied voltage is low, it can be put to practical use without providing an insulating material for preventing electric shock on its surface, and the manufacturing cost can be reduced by eliminating the need for such an insulating material.

In a preferred method of manufacturing a planar heating element according to the present invention, a flexible insulating sheet material is provided with a number of holes penetrating in a thickness direction, and is formed from a mixture of an insulating matrix material and conductive powder. A large number of heat-generating materials having substantially the same shape as the holes are punched out from the sheet material, and these heat-generating materials are embedded and fitted in the holes of the insulating sheet material. Is characterized in that an electrode connected to the end face is disposed.

According to this manufacturing method, since the heating material is punched out of a sheet material formed in advance from a mixture of the insulating matrix material and the conductive powder, the thickness of the heating material is reduced by the thickness of the insulating sheet material. In addition to being uniform, it is possible to prevent the heating material from becoming thinner than the insulating sheet material due to settling during use. Therefore, occurrence of poor contact between the heating material and the electrode can be prevented, and a sheet heating element having excellent durability can be obtained.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The planar heating element of the present invention comprises a vest,
It can be used as a material for jackets, winter clothing, clothing such as work clothes, footwear such as shoes, gloves, cushions and bedding. In addition, similarly to the conventional planar heating element, various devices having a flat or curved heating portion, such as a plate heater, a heat retaining plate, an antifreezing device, a floor, a roof, a wall surface, a carpet, a blanket, etc. It may be used for appliances, warming appliances, heating appliances and the like. In the sheet heating element of the present invention, the heating material is formed from a conductive powder and an insulating matrix material.

As the conductive powder, hollow glass spheres which are carbon, graphite or metal-plated are preferable, and graphite or metal-plated hollow glass spheres having self-temperature controllability are particularly preferable. On the other hand, as the insulating matrix material, non-conductive rubber, elastomer, or synthetic resin is preferable. The carbon, graphite, or metal-plated hollow glass sphere used as the conductive powder has an average particle size of 0.3.
It is preferably from 5 to 500 μm. The particle shape of carbon or graphite can be spherical, shell-like, scale-like, needle-like, fibrous, or the like. In particular, graphite containing a large amount of spherical particles has self-temperature controllability, and has the property of self-controlling to maintain a predetermined temperature without providing a temperature controller such as a temperature sensor or a control circuit. preferable. Further, metal-plated hollow glass spheres are particularly preferable because they have self-temperature controllability and can further reduce power consumption.

The rubber used as the insulating matrix material includes natural rubber and vulcanized rubber of synthetic rubber. Examples of the synthetic resin include a thermoplastic resin, a thermosetting resin, and the like.For example, a polyester resin, an epoxy resin, a polyamide resin, a polyimide resin, a polyolefin resin, a polyfluorocarbon resin, a polyetheretherketone resin, a polyphenylene sulfide resin, Silicone resin, polytitanocarbosilane resin and the like can be selected.
If necessary, various additives, reinforcing materials, and the like may be added to this synthetic resin. The heating material of the present invention is formed from a mixture of the conductive powder and the insulating matrix material as described above. The type and combination of these are selected according to the use of the sheet heating element and the desired heating temperature. do it. The mixing ratio between the insulating matrix material and the conductive powder can also be set according to the use of the sheet heating element, a desired heating temperature, and the like.

If the proportion of the conductive powder in the heating element is small, the resistance value increases, so that a sufficient amount of heat cannot be obtained unless the applied voltage is increased, and if the proportion of the conductive powder is large, the heat is generated. Become excessive. For example, using graphite having an average particle diameter of 500 μm or less as the conductive powder, and mixing using a silicone resin as the insulating matrix material, clothes,
When used in a heat retaining means such as shoes and gloves, the mixing ratio of graphite to the heating material is preferably 7 to 15% by weight, more preferably 8 to 11% by weight.

As the insulating sheet material used for the sheet heating element of the present invention, a flexible sheet material molded from rubber or synthetic resin can be used. As the rubber and the synthetic resin, any of the materials that can be used as the insulating matrix material can be used, and as the synthetic resin, a soft resin such as a polyvinyl resin or a polyurethane resin can be used. The thickness of the insulating sheet material is preferably in a range where the flexibility can be maintained, and is preferably 0.5 to 5 mm, more preferably 0.1 to 5 mm.
5 to 2 mm is preferred. The shape of the hole provided in the insulating sheet material is not particularly limited, but in a plan view, other than a circle and an ellipse,
The shape can be a polygon such as a triangle or a square, a cross, an X-shape, an L-shape, a star shape, or a slit shape. The arrangement interval of the holes provided in the insulating sheet material can be appropriately set according to the use or the like, and can be, for example, 2 to 20 mm, preferably 5 to 10.

As the electrode material used for the sheet heating element of the present invention, metals conventionally used for electrodes can be used. In addition, as the shape of the electrode, a linear material such as an ultrafine metal fiber, a metal-plated fiber for a synthetic fiber, or a fiber containing a conductive material in a synthetic fiber, a linear material such as a metal wire, or a linear material such as a metal wire. A wire mesh or cloth, a thin metal plate, a metal foil, or the like can be used. In particular, conductive fibers and metal foils are preferably used because they are lightweight and flexible. When using metal wire or conductive fiber directly, heat-generating materials distributed in spots
One to several wires may be connected.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an example of the sheet heating element of the present invention. This planar heating element 10 is provided in a flexible insulating sheet material 13 made of polyvinyl chloride so that a large number of holes 14 penetrate at equal intervals in the thickness direction. 11 are filled and formed to have the same thickness. The heating element 11 is formed from a mixture of an insulating matrix material made of silicone resin and a conductive powder made of graphite of spherical particles. Here, the thicknesses of the insulating sheet material 13 and the heat generating material 11 are equal. An upper electrode 12a and a lower electrode 12b made of metal foil are attached to the upper and lower surfaces of the insulating sheet material 13 and are connected to the upper and lower surfaces of the heating material 11 so as to be adhered. Upper electrode 12a
And reinforcement outside the lower electrode 12b if necessary.
A coating layer of a resin material may be coated for the purpose of waterproofing or the like.

The planar heating element 10 constructed as described above
Since the upper electrode 12a and the lower electrode 12b are arranged on both upper and lower surfaces of the heating element 11 and the distance between the electrodes is extremely close, the heating material 11 can generate heat sufficiently by applying a low voltage. In addition, since the heating materials 11 are distributed in spots at intervals, power consumption can be reduced. In addition, because the voltage is low enough that there is no risk of electric shock to the human body,
Even if the surface of both electrodes 12a and 12b is not covered with an insulating material for preventing electric shock, it can be put to practical use, and the manufacturing cost can be reduced.

FIG. 2 shows the planar heating element 10 of the present invention described above.
An example in which is applied as a heat insulating material of a vest 17 is shown. The sheet heating element 10 is cut into a predetermined shape, and is arranged between the outer material and the lining of the vest 17.
The conductor 16 is extended from a and 12b and connected to the battery 15. When the voltage of the battery 15 is applied between the upper electrode 12a and the lower electrode 12b, the planar heating element 1
0 generates heat, and the entire inside of the vest 17 can be kept at a comfortable temperature.

FIGS. 3A to 3C show an example in which the sheet heating element 10 of the present invention is used for insole of shoes. As shown in FIG. 3B, the planar heating element 10 is formed in the shape of an insole 21 of a shoe. As shown in FIG. 3C, the insole 21 is an insulating sheet material 1 previously formed into an insole shape.
3, a circular heat generating material 11 is arranged along the periphery thereof, and the arrangement density of the heat generating material 11 is particularly increased on the toe side and the heel side. The insole 21 is the work boots 2
The electrodes 12a and 12b are connected to a battery 23 on the upper part of the boot via a conductor 24.

The method for manufacturing the sheet heating element 10 of the present invention is not particularly limited, but if the manufacturing method is as follows, it is possible to make the heating material 11 less likely to settle. First, a large number of holes 14 penetrating in the thickness direction are formed in the flexible insulating sheet material 13. On the other hand, in a separate step, a sheet material having the same thickness as the insulating sheet material 13 is formed from a mixture of the insulating matrix material and the conductive powder, and a heating material having substantially the same shape as the holes 14 is formed from the sheet material. Punch out many 11. Next, these heat generating materials 11 are buried and fitted into the many holes 14 of the insulating sheet material 13. Then, electrodes 12a and 12b are attached to the upper and lower surfaces of the insulating sheet material 13, and these electrodes 12a and 12b are respectively
1 to be connected to the upper and lower ends.

The sheet heating element 10 thus manufactured
Can make the thickness of the insulating sheet material 13 and the heat generating material 11 uniform, and can prevent the heat generating material 11 from being thinned due to settling or the like during use. That is, when the heating element 11 is filled into the hole 14 from the plastic mixture and molded, the use tends to be gradually thinner during use. However, after the mixture is formed into a sheet, the heating material 11 punched out of the sheet has no settling over a long period of time and does not cause poor contact with the electrodes 12a and 12b, so that the durability can be improved. it can.

[0021]

As described in detail above, according to the planar heating element of the present invention, a large number of holes penetrating in the thickness direction are provided in a flexible insulating sheet material, and these holes are formed in an insulating matrix material. And a heat-generating material made of a mixture of conductive powder and the electrodes connected to the end faces of the heat-generating material on both upper and lower surfaces of the insulating sheet material, so that the distance between the electrodes is significantly reduced. In addition, the heating element can generate heat even at a low voltage, and power consumption can be reduced. Further, since the voltage is low, an insulating material for preventing electric shock is not required, and the manufacturing cost can be reduced.

Further, according to the manufacturing method of the present invention, since the heating material is formed by punching out a sheet material formed from a mixture of an insulating matrix material and a conductive powder, settling is less likely to occur during use. Since the contact with the electrode is always kept in a good state, the durability of the sheet heating element can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a sheet heating element of the present invention.

FIG. 2 is a perspective view showing an example of clothing using an example of the sheet heating element of the present invention.

3A is a perspective view of a shoe using an example of the sheet heating element of the present invention, FIG. 3B is a plan view of an insole of the shoe of FIG.
(C) is XX sectional drawing of (b).

FIG. 4 is an explanatory view showing a conventional planar heating element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Planar heating element 11 Heating material 12a Upper electrode 12b Lower electrode 13 Insulating sheet material 14 Hole

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3K034 AA02 AA04 AA05 AA06 AA09 AA15 AA28 AA30 AA31 AA32 BA04 BA13 BA18 BB08 BB13 BC01 BC11 BC24 CA02 CA13 CA26 CA33 GA05 HA05 JA09

Claims (8)

[Claims] 1. A flexible insulating sheet material is provided with a number of holes penetrating in a thickness direction, and these holes are filled with a heating material composed of a mixture of a conductive powder and an insulating matrix material.
A planar heating element in which electrodes connected to end faces of the heating material are respectively arranged on upper and lower surfaces of the insulating sheet material. 2. The planar heating element according to claim 1, wherein the conductive powder is a hollow glass sphere having carbon, graphite, or metal plating. 3. The method according to claim 2, wherein the matrix material is rubber, synthetic resin,
The planar heating element according to claim 1 or 2, which is an elastomer. 4. The sheet heating element according to claim 1, wherein the electrode is made of a conductive fiber or a metal foil. 5. A flexible insulating sheet material is provided with a plurality of holes penetrating in a thickness direction, and a sheet material formed from a mixture of a conductive powder and an insulating matrix material has a shape substantially the same as said holes. A large number of heat generating materials are punched out, and these heat generating materials are buried and fitted in holes of the insulating sheet material. Then, on both the upper and lower surfaces of the insulating sheet material, electrodes are connected to end faces of the heat generating material. Heating element manufacturing method. 6. The sheet heating element according to claim 5, wherein the conductive powder is carbon, graphite, or a metal-plated hollow glass sphere. 7. The matrix material is a rubber, a synthetic resin,
7. The sheet heating element according to claim 5, which is an elastomer. 8. The sheet heating element according to claim 5, wherein the electrode is made of a conductive fiber or a metal foil.