JP3458522B2 - Planar heating element and method of manufacturing the same - Google Patents

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. More specifically, the present invention relates to a planar heating element that can have a three-dimensional curved surface shape that matches the shape of an object to be heated, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Heretofore, as a planar heating element, there has been known one in which a heating resistance wire is drawn along the outer shape of a heated object and is fused to an aluminum foil as a heat diffusion medium. There is. According to such a sheet heating element, even when the heated object has a complicated three-dimensional curved surface shape such as a heating toilet seat sheet, a sheet heating element having a curved surface conforming to the outer shape is obtained. Obtainable.

However, in such a sheet heating element, since the step of forming the heating resistance wire in the forming step is manual, the manufacturing process is very troublesome and automation of the manufacturing line is hindered. There is.

On the other hand, a sheet heating element consisting of a sheet resistor formed by patterning a metal foil such as stainless steel into a predetermined shape by etching, a stretched / crystallized polyester film, a polyimide film, or other flexible or rigid film. There is known a planar heating element in which a comb-shaped pattern made of silver paste is formed as an electrode on another insulating base material, and a pattern made of carbon paste is formed as a planar resistor between the electrodes.

[0005]

However, a sheet heating element using a sheet resistor formed by etching a metal foil and a sheet heating element using a sheet resistor formed by patterning a carbon paste are flat or comparative. Although it can be formed into a curved surface shape close to the target plane, it cannot be formed into a complicated three-dimensional curved surface shape. Therefore, for example, there is a problem that it is not suitable as a heating element for heating an object to be heated having a complicated three-dimensional shape such as a heated toilet seat sheet.

Therefore, when the sheet heating element is required to have a predetermined three-dimensional shape, it is possible to use the sheet heating element produced by arranging a heating resistance wire and fusing it to an aluminum foil. But in this case,
In addition to the above-mentioned problems in the manufacturing process, there is a further problem that the thermal efficiency is low.

The present invention is intended to solve the problems of the prior art as described above, and can be easily formed into a three-dimensional shape suitable for the shape of the object to be heated, and is also excellent in thermal efficiency. The purpose is to be able to obtain a sheet heating element.

[0008]

DISCLOSURE OF THE INVENTION The inventors of the present invention heat-mold a laminate of an insulating base material made of a thermoplastic resin and a thermoplastic conductive composition to obtain a surface having an arbitrary three-dimensional shape. The inventors have found that it is possible to easily form a heating element, and have completed the present invention.

That is, the present invention relates to a sheet heating element comprising an insulating base material, a sheet resistor formed on the insulating substrate, and a pair of electrodes connected to the sheet resistor. , the insulating substrate is made of a thermoplastic resin, the planar resistor is made of a thermoplastic conductive composition state, and are not the insulating substrate and the planar resistor are both heated molding surface Resistance body or surface
At least one good conductor region on the strip resistor intersects the electrode.
Providing a planar heating element, characterized that you have been formed so as not to straw.

Further, this is a method for manufacturing the sheet heating element.
Te, the thermoplastic thermoplastic resistor formed on a resin sheet of the conductive composition layer and the electrode formation pattern are stacked, in this method for producing a laminate heated mold to that the planar heating element, the
In a thermoplastic conductive composition layer for forming a resistor or forming a resistor
For forming an electrode on the thermoplastic conductive composition layer
To form a good conductor area forming pattern,
Then, there is provided a manufacturing method characterized in that the laminate is heat-molded.

The present invention will be described in detail below.

The sheet heating element of the present invention comprises an insulating substrate made of a thermoplastic resin, and a sheet resistor made of a thermoplastic conductive composition laminated on the insulating substrate. By thus forming both the insulating base material and the sheet resistor from the thermoplastic material, it becomes possible to easily heat-mold the laminate into a desired shape. Therefore, even if the object to be heated has a complicated three-dimensional shape such as a heated toilet seat sheet, the planar heating element of the present invention can have a shape suitable for the complicated shape of the object to be heated. it can.

Here, the thermoplastic resin constituting the insulating base material is preferably a resin having good moldability, and examples thereof include polyethylene terephthalate (PET), polycarbonate, polystyrene, polypropylene and polyethylene. Of these, non-stretched and amorphous amorphous PET is preferable because it has solvent resistance and is excellent in printability when a sheet-shaped resistor or an electrode is formed by printing as described later.

As the thermoplastic conductive composition for forming a resistor for forming a sheet resistor, the above-mentioned thermoplastic resin is used as a binder, and carbon particles, graphite particles, silver particles, copper particles are contained therein. Metal particles such as nickel particles and nickel / gold particles, or particles in which conductive particles such as particles obtained by metal-coating insulating particles are dispersed can be preferably used. In this case, from the viewpoint of moldability, it is particularly preferable that the thermoplastic conductive composition uses a vinyl resin as its binder.

In the sheet heating element of the present invention, the material for forming the electrodes connected to the sheet resistor is not particularly limited. For example, it may be formed from a metal foil tape, or may be formed using a conductive resin composition in which conductive particles such as silver particles and copper particles are dispersed in a binder.

In the sheet heating element of the present invention, a thermoplastic resin may be further formed on the sheet resistor according to need such as protection of the sheet resistor, improvement of fitting property with an object to be heated, and electrical insulation. Can have an outer layer of The outer layer made of this thermoplastic resin layer is also made of a thermoplastic resin having good moldability in order to make it possible to easily produce the sheet heating element in a desired outer shape. It is preferable to heat-mold with the body.

In the sheet heating element of the present invention, an adhesive and a release sheet are sequentially laminated on the surface of the sheet heating element for the convenience of adhering and fixing the sheet resistor to a predetermined object to be heated. Good.

Further, at least one good conductor region may be formed in or on the planar resistor so as not to intersect the electrodes. Here, it is assumed that the good conductor region is formed of a material having a higher conductivity than that of the sheet resistor.
Thereby, the heat generation distribution of the sheet-shaped resistor can be controlled, and the sheet-shaped heating element can have a desired temperature distribution.

That is, if the planar heating element is simply formed of the insulating base material, the planar resistor and the electrodes, the current flowing through the planar resistor concentrates in the area that is the shortest distance between the electrodes. When the sheet-shaped resistor is formed on a curved surface, a specific region that gives the shortest distance between the electrodes generates heat intensively, and the entire region of the sheet-shaped heater cannot be heated to a uniform temperature. Further, when the planar heating element has a wide region and a narrow region, the resistance in the wide region is lower than that in the narrow region, so the heat temperature in the wide region is lower than that in the narrow region. The temperature becomes low, and the entire area of the planar heating element cannot be heated to a uniform temperature. Furthermore, in the heated toilet seat sheet, it is preferable to have a distribution of heat generation temperature so that the temperature of a portion that comes into direct contact with the skin is higher when a person sits down, rather than heating the entire area to a uniform temperature. In this way, it is impossible to give a desired temperature distribution. On the other hand, by forming at least one good conductor region in or on the planar resistor so as not to intersect the electrodes, it becomes possible to control the current distribution in the planar resistor. The entire area of the planar heating element can also be heated to a uniform temperature, and can also be heated to have a desired temperature distribution.

The shape, number and arrangement of the good conductor regions can be appropriately determined according to the shape of the sheet resistor and the desired temperature distribution, etc., as long as the good conductor regions do not intersect the electrodes. When the good conductor region intersects with the electrode of the planar resistor, the intersecting good conductor region is located between the electrodes and does not perform the above-described function of the good conductor region of controlling the current distribution of the planar resistor. Will function as.

The sheet-like resistor of the present invention comprising the insulating base material, sheet-like resistor and electrode as described above, or the sheet-like sheet of the present invention further having a good conductor region and an outer layer formed of a thermoplastic resin layer, if necessary. The heating element can be easily manufactured by the following method of the present invention.

First, as a thermoplastic resin sheet forming the insulating base material, a thermoplastic resin sheet having good moldability, such as polyethylene terephthalate (PET), polycarbonate, polystyrene, polypropylene, polyethylene, etc., is prepared. As such a sheet, as described above, in consideration of solvent resistance and printability, in particular, no stretching,
Amorphous amorphous PET sheet is preferred.

Next, the resistor-forming thermoplastic conductive composition layer as described above is formed in a predetermined planar pattern on the thermoplastic resin sheet. In this case, the formation of the resistor-forming thermoplastic conductive composition layer may be performed using a coater such as a roll coater or a gravure coater, or may be performed by printing.

On the thermoplastic resin sheet, an electrode forming pattern to be a pair of electrodes of the sheet resistor is formed.
This electrode forming pattern may be formed by applying a conductive composition such as a silver paste or a copper paste to a predetermined pattern, or a metal foil such as a copper tape, a silver tape or an aluminum tape having a predetermined pattern. It may be formed by adhering to a pattern.

If necessary, a good conductor region forming pattern is formed in or on the layer of the resistor forming thermoplastic conductive composition so as not to intersect with the electrode forming pattern. As described above, the good conductor region forming pattern is formed as long as it is formed of a material having a higher conductivity than the planar resistor.
The constituent material is not particularly limited. Therefore, it is preferable to use the same conductive material as the electrode forming pattern and to form it in the same step as the electrode forming pattern. Thereby, the manufacturing process of the sheet heating element can be simplified.

Further, in order to form an outer layer made of a thermoplastic resin, if necessary, a thermoplastic resin sheet for forming an outer layer is provided with a sheet-like resistor (or, if necessary, a sheet-like resistor having a good conductor region formed therein). ). A pressure-sensitive adhesive may be used for laminating the thermoplastic resin sheets.

Further, for the convenience of adhering and fixing the sheet resistor to a predetermined object to be heated, an adhesive and a release sheet may be sequentially laminated on these outermost surfaces.

After laminating the thermoplastic resin sheet, the resistor-forming thermoplastic conductive composition layer, the electrode-forming pattern, and the like in this manner, these laminates are heat-molded. This heat molding method can be vacuum molding, pressure molding, or the like, and can be molded at a temperature of 90 to 110 ° C. and about 1 atm. As a result, the laminated body can be formed into a molded product having a three-dimensional curved surface that just fits the object to be heated.

Thereafter, if necessary, the outer shape of the molded product is cut to obtain a sheet heating element.

The sheet heating element of the present invention can be used for various purposes, for example, heating toilet seat, washbasin, floor heating, electric blanket, kotatsu, car door mirror and rearview mirror, and snow removal. It can be used for roofs, etc.

[0031]

Since the sheet heating element of the present invention uses the sheet resistor as the heating resistor, it can be produced more easily than the case where the heating resistor wire is drawn and fused to the aluminum foil. Enables line automation. In addition, heat is generated from the entire surface of the resistor, resulting in high heat generation efficiency.

Further, the sheet heating element of the present invention is formed by heating and molding a laminate of an insulating base material made of a thermoplastic resin and a thermoplastic conductive composition forming a sheet resistor. Therefore, it can have a complicated three-dimensional shape. Therefore, the sheet heating element of the present invention is a perfect fit for the shape of the object to be heated.

Further, in the planar heating element of the present invention in which the good conductor regions are formed in the planar low antibody or on the planar resistor, the planar conductor is formed by appropriately determining the shape, number and arrangement of the good conductor regions. Since the current distribution of the resistor is controlled, the distribution of heat generation temperature is controlled. Therefore, to generate a uniform temperature over the entire area of the planar heating element,
It is possible to form the high temperature region or the low temperature region in a predetermined region.

[0034]

Embodiments of the present invention will be described below in detail with reference to the drawings.

Example 1 As shown in FIG. 1 (a-i: sectional view) and (a-ii: plan view), an amorphous PET sheet having a thickness of 200 μm (Tetron sheet manufactured by Teijin Ltd.) was insulated. In order to form the sheet-shaped resistor 2 on the flexible substrate 1, a vinyl-based carbon paste (J8836, manufactured by DuPont) is printed by a screen printing machine so that the dry thickness is 10 μm, and the temperature is 15 ° C. at 15 ° C. Dry for minutes.

Next, the electrodes 3a, 3b (width 7 mm) and a plurality of strip-shaped good conductor regions 4 (width 3 mm, spacing 3) parallel to the electrodes.
0 mm) was formed in the same step, a pattern of vinyl silver paste (J8821 manufactured by DuPont) was printed by a screen printing machine so that the dry thickness was 13 μm, and this was dried at 100 ° C. for 30 minutes.

In order to form the outer layer 5 thereon, a pressure sensitive adhesive 6 with release paper (T4100 manufactured by Sony Chemical Co., Ltd.) was laminated using a laminator (60 ° C.), and the release paper was peeled and removed. A 200 μm-thick amorphous PET sheet 7 (Tetoron sheet, manufactured by Teijin Ltd.) was laminated on the top using a laminator (60 ° C.).

Furthermore, in order to form an adhesive layer 8 for adhering and fixing the sheet heating element to the object to be heated, an adhesive 10 with a release film having a polyethylene film as a release film 9 (Sony Chemical Company) is used. Made, NP40
4) was laminated using a laminator (60 ° C.) to obtain a laminate.

On the other hand, a commercially available plastic heated toilet seat sheet is used as an object to be heated, a mold of this heated toilet seat sheet is prepared, and a vacuum forming machine (90 to 110 ° C., 1 atm) is used. It was molded so as to have the cross-sectional shape shown in FIG. 1 (b), and the outer shape was cut off at the position shown by the broken line A to obtain the planar heating element of the example.

The peeling film 9 on the surface of the obtained sheet heating element was peeled off and adhered to one surface of the heated toilet seat sheet as the article to be heated. Then, a thermocouple is attached to each of the surface of the sheet heating element adhered to the heating toilet seat sheet and the surface of the sheet heating sheet opposite to the sheet heating element, and 50 V is applied between the electrodes 3a and 3b of the sheet heating element. By applying 60 V or 70 V, the surface temperature of the sheet heating element and the surface temperature of the heated toilet seat sheet on the side opposite to the sheet heating element were measured (room temperature 24 ° C.).

The results are shown in FIGS. 2 (a)-(c). In the figure, the solid line represents the surface temperature of the sheet heating element, and the broken line represents the surface temperature of the heating toilet seat on the side opposite to the sheet heating element.

Comparative Example 1 As shown in FIG. 3, an aluminum foil 31 having a thickness of 80 μm was punched out in the same outer shape as that of the sheet heating element of Example 1, and a nichrome wire was used to generate heat. Resistance wire 3
2 is routed as shown in the figure, and aluminum foil 3
A commercially available heating element in which 1 and the heating resistance wire 32 were fused was prepared.

This heating element was adhered to a commercially available plastic heating toilet seat sheet similar to that used in Example 1, a thermocouple was attached to the surface of the heating element and the surface of the heating toilet seat sheet on the opposite side to 50 V between the electrodes, By applying 60 V or 70 V, the surface temperature of the heating element and the surface temperature of the heated toilet seat sheet on the side opposite to the heating element were measured (room temperature 24 ° C.).

The results are shown in FIGS. 4 (a)-(c). In the figure, the solid line represents the surface temperature of the heating element, and the broken line represents the surface temperature of the heating toilet seat opposite to the heating element.

Evaluation From the results of FIG. 2 and FIG.
It can be seen that the surface temperature of the heated toilet seat sheet when V is applied is equal to the surface temperature of the heated toilet seat sheet when 70 V is applied to the heating element of Comparative Example 1 at 36 ° C.

When the resistance of the sheet heating element of Example 1 and the resistance of the heating element of Comparative Example 1 were measured, they were 179 respectively.
.OMEGA. (Example 1) and 185 .OMEGA. (Comparative Example 1).
The power was 1 W (Example 1) and 26.6 W (Comparative Example 1).

Therefore, according to the planar heating element of Example 1, the power consumption is reduced by 24.4% as compared with the heating element of Comparative Example 1, and the thermal efficiency is improved.

[0048]

According to the present invention, it becomes possible to easily obtain a planar heating element which can be easily formed into a three-dimensional shape suitable for the shape of the object to be heated and which has excellent thermal efficiency.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a planar heating element of an example.

FIG. 2 is a diagram showing a time-dependent change in heat generation temperature of the planar heating element of the example.

FIG. 3 is an explanatory diagram of a planar heating element of a comparative example.

FIG. 4 is a diagram showing a time-dependent change in heat generation temperature of a planar heating element of a comparative example.

[Explanation of symbols]

1 Insulating base material Biplane resistor 3a, 3b electrodes 4 Band-shaped good conductor area 5 outer layers 6 Adhesive 7 PET sheet 8 Adhesive layer 9 Release film 10 Adhesive with release film

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H05B 3/20 A47K 13/30 H05B 3/10

Claims (7)

(57) [Claims] 1. A planar heating element comprising an insulating base material, a planar resistor formed on the insulating base material, and a pair of electrodes connected to the planar resistor, wherein the insulating the substrate is made of a thermoplastic resin, the planar resistor is made of a thermoplastic conductive composition state, and are not the insulating substrate and the planar resistor is both hot forming, the planar resistive body or Less on the sheet resistor
Formed so that one good conductor area does not intersect with the electrode
A planar heating element, characterized that you have been. 2. An outer layer made of a thermoplastic resin is formed on the planar resistor, and the outer layer made of the thermoplastic resin is
The sheet heating element according to claim 1, which is formed by heating together with an insulating base material and a sheet resistor. 3. The sheet heating element according to claim 1 or 2 , wherein the sheet heating element has a three-dimensional curved surface shape that fits the outer shape of the toilet seat sheet. Wherein the thermoplastic conductive composition layer and the electrode formation pattern generating resistor formed on the thermoplastic resin sheet are laminated, the laminate production method of heat molding to that planar heating element
In the thermoplastic conductive composition layer for forming the resistor,
Is for forming electrodes on the thermoplastic conductive composition layer for forming resistors
A pattern for forming a good conductor area so that it does not overlap the pattern
Down to form, then especially to thermoforming the laminate
Manufacturing method for a butterfly. Hot forming of 5. A laminate, carried out by vacuum molding to mold an object to be heated, the sheet heating element according to claim 4, wherein molding a planar heating element into a shape adapted to the contour of the object to be heated Manufacturing method. 6. A thermoplastic resin sheet for forming a resistor, a pattern for forming an electrode, and a pattern for forming a good conductor region are formed on a thermoplastic resin sheet, and then a thermoplastic resin sheet for forming an outer layer is laminated thereon. The method for producing a planar heating element according to claim 4 , wherein the laminate is then heat-molded. 7. The method for manufacturing a sheet heating element according to claim 6 , wherein the sheet heating element is molded so as to have a three-dimensional curved surface shape conforming to the outer shape of the toilet seat sheet.