JPH08106971A - Planar heating element - Google Patents

Abstract

(57) [Abstract] [Purpose] The circumference of the electrode wire can be thinned, and the electrode wire can be easily attached to the heating resistance sheet.
To provide a sheet heating element with improved handleability. A heating resistance sheet 2 formed by molding a heat-generating composition into a plane, and a group of electrode wires in which a plurality of the heat-generating composition and a single wire 3A of a conductor for an electrode are arranged in parallel and in a flat plate shape without intersecting each other. 3 and at least two coated wire rods 4 which are formed by coextrusion molding and are separated from each other by a predetermined distance and fused to each other to form a planar heating element 1, and the coated wire rods 4 generate heat. The composition has a structure showing an electric resistance value equal to or lower than that of the heat generating composition of the heat generating resistance sheet 2, and having a positive temperature coefficient characteristic.

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, which can be used as, for example, a snow melting heater for roads and roofs, or an antifogging heater for mirrors.

[0002]

BACKGROUND ART Due to snow melting on a road, a planar heating element is embedded near the surface of the road to heat the planar heating element. This planar heating element is a heating resistance sheet formed by mixing conductive particles such as carbon black into a thermoplastic resin and provided with a pair of electrode wires. This is a structure in which the sheet generates heat due to heat. As a conventional example, a sheet-like heating element obtained by coextrusion of a heat-generating composition obtained by mixing conductive particles such as carbon black with a thermoplastic resin and a wire having a conductive wire for electrodes (Japanese Patent Publication No. 54-42690). Conventional example 1), a sheet heating element (conventional example 2) attached by wire-bonding to a heating resistance sheet by thermocompression bonding, and a floor heating for sewing copper foil to a heating resistance plate made of ethylene glycol and carbon black with a sewing machine. Heating element (conventional example 3), a sheet-shaped heating element in which a metal plate such as copper or aluminum is sewn or thermocompression-bonded to a heating resistance sheet with a sewing machine (JP-A-51-48843: Conventional example 4), thermoplastic A sheet heating element in which a coated wire material obtained by coextrusion molding a thermal composition having a resin and conductive particles and an electrode wire that is a stranded wire, a braided wire, or a single wire is heat-fused on the surface of a heating resistance sheet. (Patent application
1-219731: Conventional example 5).

[0003]

In the sheet heating element of Conventional Example 1, since the electrode lead wire is co-extruded with the heat generating composition as a stranded wire, the circumference of the electrode lead wire becomes thicker than other portions. However, embedding in the vicinity of the road surface becomes inconvenient. Furthermore, when changing the electrode wire interval, the die of the extrusion molding device must be changed, and there is a restriction in changing the shape of the planar heating element. In the planar heating element of Conventional Example 2, the wire is directly thermocompression bonded to the heating resistance sheet, so that there is a problem that there is a defective crimping point. If there is a defective crimping point, there is the disadvantage that heat is generated from that point. In the heating element of Conventional Example 3, since the heating resistance plate itself is hard, it will break when bent, which is inconvenient to handle. In the sheet heating element of Conventional Example 4, since the metal plate is sewn or thermocompression-bonded with the sewing machine, the manufacturing process becomes complicated, and
There is a problem that crimping failure occurs. In the planar heating element of Conventional Example 5, regardless of whether the electrode wire is a stranded wire or a single wire, the entire electrode wire must be thickened in order to flow a predetermined current through the electrode wire. There is a problem that the surrounding area is thicker than other areas.

An object of the present invention is to provide a planar heating element which can be thinned around the electrode wire, can be easily attached to the heating resistance sheet, and has improved handleability.

[0005]

SUMMARY OF THE INVENTION Therefore, the present invention is intended to achieve the above object by arranging a plurality of single wires of the electrode conductive wire of the covered wire material in parallel and in a flat plate shape without crossing each other. Specifically, the sheet heating element of the present invention includes a heating resistance sheet formed by sheet-forming a heating composition having a thermoplastic resin and conductive particles, and a thermoplastic resin and conductive particles. The exothermic composition and a plurality of electrode wire groups in which a plurality of electrode wires are arranged in parallel and in a flat plate shape without intersecting each other are formed by coextrusion molding, and are fused and separated from each other by a predetermined distance to the exothermic resistance sheet. At least two coated wire rods are provided, and the heat-generating composition of the coated wire rods has an electric resistance value equal to or lower than that of the heat-generating composition of the heat-generating resistance sheet, and has a positive temperature coefficient characteristic. .

Here, in the covered wire, for example, like a trapezoidal cross section, a portion to be fused with the heat generating resistance sheet and a portion opposite to this portion are formed in a flat shape, and The width dimension of the portion to be fused may be formed to be longer than the width dimension of the portion opposite to the portion to be fused with the heating resistance sheet, or, for example, as in the case of a triangle or a pentagon in cross section, with the heating resistance sheet. The portion to be fused may be formed in a planar shape and may have a tapered portion whose width dimension becomes shorter as the distance from the portion to be fused with the heating resistance sheet decreases. Furthermore, the heat-generating composition of the coated wire has an electric resistance value of 0.5 to 1000 Ω · cm, and the ratio of the maximum resistance value to the room temperature resistance value is 10 ³ or more, and the electric resistance of the heat-generating composition of the heat-generating resistance sheet. The value may be 10 to 50000 Ω · cm.

[0007]

The coated wire material is obtained by a coextrusion method in which a plurality of single conductors for electrodes are passed through a die of an extrusion molding machine in a parallel state without crossing each other, and a heat generating composition is extruded together with the single conductors for electrodes. To manufacture. The exothermic resistance sheet is formed by extruding the exothermic composition into a sheet or film. At least two coated wire rods are fused on the surface of this heat generating resistance sheet by heat sealing or the like, and the heat generating resistance sheet and the coated wire rods are covered with an exterior material to manufacture a planar heating element. The coating of the exterior material may be performed by laminating a sheet-like exterior material on both surfaces of the heat resistance sheet and the covered wire material. In this planar heating element, since the electrode conductive wire is formed by arranging a plurality of single wires along the surface of the heat generating resistance sheet, it is possible to make the covered wire material thin and to secure the sectional area of the entire electrode conductive wire. A necessary current can be passed through this electrode lead wire. Moreover,
The heat generating composition of the coated wire shows an electric resistance value equal to or lower than that of the heat generating composition of the heat generating resistance sheet, and since it has a positive temperature coefficient characteristic, it appropriately generates heat in the heat generating resistance sheet,
The coated wire does not generate heat.

Here, a portion of the coated wire material that is fused to the heat generating resistance sheet and a portion opposite to this portion are formed in a flat shape, and the width dimension of the portion that is fused to the heat generating resistance sheet is set to the heat generating resistance. It is formed to be longer than the width dimension of the portion on the side opposite to the portion to be fused with the sheet, or the portion to be fused with the heating resistance sheet is formed in a flat shape, and the width dimension is fused with the heating resistance sheet. If the taper portion is configured to become shorter as the distance from the portion to be heated is reduced, air will not be accumulated between the exterior material and the heat-generating resistance sheet or the covered wire when the heat-generating resistance sheet and the covered wire are laminated with the exterior material. . Furthermore, the exothermic composition of the coated wire has an electric resistance value of
If the ratio of the maximum resistance value to the room temperature resistance value is 10 ³ or more, and the electric resistance value of the heat generating composition of the heat generating resistance sheet is 10 to 50000 Ωcm, the surface condition is 0.5 to 1000 Ωcm. The heating element will have proper positive temperature coefficient characteristics.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, in each of the embodiments, the same components are designated by the same reference numerals, and the description thereof will be omitted or simplified. 1 and 2 show a first embodiment of the present invention. FIG. 1 is a perspective view in which a part of a planar heating element is broken, and FIG. 2 is a plan view thereof. In these figures, the sheet heating element 1 is formed by coextrusion molding a heating resistor sheet 2 formed by molding a heating composition into a rectangular surface, an electrode wire group 3 and a heating composition. It is configured to include a covered wire 4 and an exterior material 5 in which the heating resistance sheet 2 and the covered wire 4 are laminated.

The exothermic resistance sheet 2 is formed by extruding the exothermic composition into a sheet or film and has a thickness of 0.1 to 5 mm, preferably 0.1 to 2 mm and a width of 2.5 mm. It is ~ 2000 mm and its length is not limited. The electrode wire group 3 is formed by arranging a plurality of single wires 3A of conductors for electrodes in a row in parallel and in a flat plate shape without intersecting each other. The single wires 3A have a thickness of 2 mm or less and 0.1 mm or less.
As described above, the specific thickness is determined in relation to the number of single wires 3A. That is, a constant cross-sectional area is required for the electrode wire group 3 as a whole in order to pass a predetermined amount of current through the electrode wire group 3.
Since this cross-sectional area is determined by the cross-sectional area of one single wire 3A and the number of single wires 3A, if the number of single wires 3A is increased, the single wire 3A can be made thin. The electrode wire group 3 is
When a thin wire is used as the single wire 3A, these may be arranged in two rows to form a flat plate. However, single line 3
When the thickness of A exceeds 2 mm, the coated wire 4 itself becomes thicker, so that when the coated wire 4 is laminated with the exterior material 5, air easily enters between the exterior material 5 and the heating resistance sheet 2,
The inconvenience arises that the performance of the sheet heating element 1 deteriorates.

The covered wire 4 is formed in an elongated shape, and two wires are fused on both sides of the heating resistance sheet 2 along the length direction. The fusion of the covered wire 4 and the heat generating resistance sheet 2 is performed by heat sealing or ultrasonic sealing. The coated wire 4 is formed in a rectangular cross section having a thickness of 0.3 mm to 5 mm and a width of 0.5 mm to 30 mm, preferably 1 mm to 10 mm, and one side surface thereof is in the same plane as the side surface of the heating resistance sheet 2. The ratio of the width L ₁ of the covering wire 4 and the width L ₂ of the heat generating resistive sheet 2 (L ₁
/ L ₂ ) is 0.015 or more and 0.2 or less. Spacing the covering wire 4 having a width dimension L ₁ and the heat generating resistive sheet 2 of the width L ₂ ratio of the adjacent exceeds 0.2 coated wire 4 is exothermic area decreases short, uniform heating is less than 0.015 Is impossible. The covered wire 4 is manufactured by a co-extrusion method in which a plurality of single wires 3A of electrode conductive wires are passed through a die of an extrusion molding machine in a parallel state without crossing each other and the exothermic composition is extruded together with these electrode conductive wires.

The heat-generating composition of the heat-generating resistance sheet 2 and the coated wire 4 has a thermoplastic resin and conductive particles, respectively.
It has a positive temperature coefficient characteristic (PTC characteristic) in which the electric resistance value increases as the temperature rises. As the thermoplastic resin, a crystalline thermoplastic resin is preferable, and specifically, a polyolefin resin and a copolymer resin thereof, a polyamide resin, a polyacetal resin, a thermoplastic polyester resin, a polyphenylene oxide and nonyl resin, a polysulfone and the like. Can be mentioned.

Examples of the polyolefin resin include polyethylenes such as high density polyethylene, medium and low density polyethylene and linear low density polyethylene, polypropylenes such as isotactic polypropylene and syndiotactic polypropylene, polybutene, 4- Methyl pentene-1 resin etc. can be mentioned. In addition, in this example, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer and other ethylene- An acrylate-based copolymer, a copolymer of an olefin and a vinyl compound such as an ethylene-vinyl chloride copolymer, a fluorine-containing ethylene copolymer, and modified products thereof can also be used.

As the vinyl acetate resin, for example,
Vinyl acetate resin, polyvinyl acetoacetal, polyvinyl butyral, etc. can be mentioned. Examples of the polyamide resin include nylon 6, nylon 8, nylon 11, nylon 66, nylon 610 and the like. The polyacetal may be a homopolymer or a copolymer. Examples of the thermoplastic polyester resin include polypropylene terephthalate,
Examples thereof include polybutylene terephthalate.
In addition to the above, as the crystalline thermoplastic resin, for example, diene-based polymers and copolymers such as trans-1,3-polyisoprene and syndiotactic-1,2-polybutadiene are also used. be able to.

The various crystalline thermoplastic resins may be used alone or in combination of two or more as a polymer blend or the like. However, among the various crystalline thermoplastic resins described above, olefin-based copolymers such as high-density polyethylene, low-density polyethylene, linear polyethylene, ethylene-vinyl acetate copolymer, and ethylene-ethyl acrylate copolymer, and trans. -1,4-polyisoprene and the like are preferable. The various crystalline thermoplastic resins described above can also be used as a composition with other polymers and additives as required. In the present example, the thermoplastic resin used in the heat-generating composition of the heat-generating resistance sheet 2, particularly the crystalline thermoplastic resin, and the thermoplastic resin used in the heat-generating composition of the covered wire 4, especially the crystalline thermoplastic resin. The resins may be of the same type as each other, or may be different.
However, it is usually desirable to use the same kind in order to keep the adhesiveness by heat fusion better.

Examples of the conductive particles include granular materials such as carbon black particles and graphite particles, powder materials such as metal powder and metal oxide powder, and fibrous materials such as carbon fibers. . Among these, granular materials such as carbon black particles and graphite particles, particularly carbon black particles are preferable. The various conductive particles are 1
They may be used alone or in combination of two or more. The particle size of the conductive particles is not particularly limited, but for example, the average particle size is usually 10 to 200 nm, preferably 15 to 100 nm. When the conductive particles are fibrous, the aspect ratio is usually 1 to 1000, preferably,
It is about 1 to 100.

In the present embodiment, the conductive particles used for the heat generating composition of the heat generating resistance sheet 2 and the conductive particles used for the heat generating composition of the covered wire 4 may be of the same type, Alternatively, they may be different. The mixing ratio of the crystalline resin and the conductive particles, as a weight ratio, usually,
It is 10 to 80:90 to 20, preferably 55 to 75:45 to 25.
When the compounding ratio of the conductive particles is less than this range, the electric resistance value of the heating resistance sheet 2 and the covered wire 4 becomes large, and the sheet heating element 1 may not generate sufficient heat in practical use. If the blending ratio of is larger than this range, the positive temperature coefficient characteristic will not be sufficiently exhibited.

Electric resistance of the exothermic composition of the exothermic resistance sheet 2
The value can be appropriately selected according to the specifications and purpose,
Usually 10 to 50000 Ωcm, preferably 40 to 2000
It is 0 Ω · cm. The exothermic composition of the covered wire 4 should be
Since it has a temperature coefficient characteristic, its electrical resistance value is 0.5 to 10
00Ω ・ cm, and the ratio of maximum resistance value to room temperature resistance value is 10 ³
That is all. The ratio of the maximum resistance value to the room temperature resistance value is 10³Less than
Has a sufficient withstand voltage for practical use as a heating element.
I can't let you. In addition, the heating resistance sheet 2 is
Temperature at which the electric resistance value is 10 times the electric resistance value at room temperature
Those having a degree of 40 to 80 ° C. are preferable because of high practicality.
If the temperature is less than 40 ° C, the calorific value is not sufficient,
If the temperature exceeds 80 ° C, the temperature of the heating element will be too high.
In addition, there is an inconvenience that the power consumption also increases.

However, the exothermic composition of the coated wire 4 has an electric resistance value equal to or lower than that of the exothermic composition of the exothermic resistance sheet 2. When the electric resistance value of the exothermic composition used in the coated wire material 4 is higher than the electric resistance value of the exothermic composition used in the exothermic resistance sheet 2, inconvenience that heat is generated not in the exothermic resistance sheet 2 but in the covered wire material 4. Occurs.
The heating resin sheet 2 and the covered wire 4 are obtained by mixing and molding the crystalline resin and conductive particles. The thermoplastic crystalline resin in the heat-generating composition is crosslinked during or after the molding. It is preferred to cure the exothermic composition.
When this exothermic composition is cured, the positive temperature characteristics are improved, and defects due to thermal deformation or thermal softening of the sheet heating element 1 can be prevented.

Crosslinking of the crystalline thermoplastic resin can be accomplished by using a crosslinking agent and / or
Alternatively, radiation can be used. The cross-linking agent can be appropriately selected and determined from organic peroxides, sulfur compounds, oximes, nitroso compounds, amine compounds, polyamine compounds, etc., depending on the type of crystalline thermoplastic resin. For example, when the crystalline thermoplastic resin is a polyolefin resin or the like, an organic peroxide can be used as a suitable crosslinking agent. Examples of the organic peroxide include benzoyl peroxide, lauroyl peroxide, dicumyl peroxide, tert-butyl peroxide, tert-butyl peroxybenzoate, tert-butyl cumyl peroxide, te.
rt-Butyl hydroperoxide, 2,5-dimethyl-
2,5-di (tert-butylperoxy) hexyne-3,
1,1-bis (tert-butylperoxyisopropyl)
Benzene, 1,1-bis (tert-butylperoxy)-
3,3,5-trimethylcyclohexane, n-butyl-
4,4-bis (tert-butylperoxy) valerate,
2,2-bis (tert-butylperoxy) butane, tert
-Butyl peroxybenzene etc. can be mentioned.

Of these, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3 is particularly preferable.
Etc. are preferred. In addition, these various organic peroxides are 1
The seeds may be used alone, or if necessary, a crosslinking aid such as triallyl cyanurate, divinylbenzene, triallyl isocyanurate may be added. The amount of the organic peroxide used is usually 0.01 to 5 parts by weight, preferably 0.05 to 2 parts by weight, based on 100 parts by weight of the crystalline resin. If this proportion is less than 0.01 parts by weight, crosslinking will be insufficient and the positive temperature coefficient characteristics will not be sufficiently exhibited, and problems such as a decrease in resistance in the high temperature region tend to occur. On the other hand, if the amount exceeds 5 parts by weight, the degree of cross-linking becomes too high, resulting in deterioration of moldability and deterioration of positive temperature coefficient characteristics.

The exterior material 5 is made of a heat-resistant resin such as polyethylene terephthalate, nylon, polycarbonate, vinylidene chloride, polyethylene, polypropylene or the like, and has a thickness of 0.001.
The length is up to 5 mm, the length is 1 to 100 mm longer than the length of the heating resistance sheet 2, and the width is 1 than the width of the heating resistance sheet 2.
~ 100 mm long. An adhesive layer (not shown) is provided between the exterior material 5 and the heating resistance sheet 2. This adhesive layer is for preventing peeling between the exterior material 5 and the heat generating resistance sheet 2. In the drawings, the thickness of the exterior sheet 5 is exaggerated compared to the actual thickness in order to make the configuration easy to understand. Two exterior materials 5 are laminated on both sides of the heat generating resistance sheet 2 to which the covered wire 4 is fused.

Therefore, according to this embodiment, the heat-generating resistance sheet 2 formed by planarly molding the heat-generating composition containing the thermoplastic resin and the conductive particles, and the heat-generating sheet containing the thermoplastic resin and the conductive particles. Heat-generating resistance sheet 2 formed by co-extrusion molding a composition and a plurality of electrode wire groups 3 in which a plurality of single wires 3A of electrode lead wires are arranged in parallel and in a flat plate shape without intersecting each other.
A plurality of covered wire rods 3 which are separated from each other by a predetermined distance and fused together
Since the planar heating element 1 is configured by including, the plurality of single wires 3A of the electrode wire group 3 are formed side by side along the surface of the heating resistance sheet 2, so that the circumference of the electrode wire group 3 is thinned and Since the electrode wire group 3 can be easily attached to the heat generating resistance sheet 2, and the sheet heating element 1 can be bent, the handleability is improved.

Moreover, since the heat-generating composition of the coated wire 4 exhibits an electric resistance value equal to or lower than that of the heat-generating composition of the heat-generating resistance sheet 2 and has a positive temperature coefficient characteristic, the heat-generating resistance sheet 2 appropriately generates heat. be able to. The heat-generating composition of the coated wire 4 has an electric resistance value of 0.5 to 1000 Ω · cm and a ratio of the maximum resistance value to the room-temperature resistance value of 10 ³ or more. Value from 10 to
Since it is set to 50000 Ω · cm, the sheet heating element 1 can have an appropriate positive temperature coefficient characteristic.

Next, a second embodiment of the present invention will be described with reference to FIGS.
It will be described based on. The second embodiment is different from the first embodiment in that the shape of the covered wire is different, but the other configurations are the same as those in the first embodiment. FIG. 3 is a perspective view in which a part of the planar heating element of the second embodiment is cut away, and FIG. 4 is a sectional view thereof. In these figures, the sheet heating element 11 includes the heating resistance sheet 2, two covered wire rods 14 formed by coextrusion molding of the electrode wire group 3 and the heating composition, and these heating resistance sheets. 2 and the sheathing material 5 in which the covered wire material 14 is laminated.

The covered wire 14 has a portion 14A which is fused with the heat generating resistance sheet 2 and a portion 14 opposite to the portion 14A.
B has a planar shape, and the width dimension L ₃ of the portion 14A that is fused with the heating resistance sheet 2 is the portion 1 that is fused with the heating resistance sheet 2
It is formed in a trapezoidal cross section that is longer than the width dimension L ₁ of the portion 14B on the side opposite to 4A. Heat resistance sheet 2 for covered wire 14
The edge of the portion 14 </ b> A that is to be fused with is aligned with the side surface of the heat generating resistance sheet 2. The cross-sectional shape of the covered wire material 14 is not limited to the trapezoidal shape shown in FIGS. 3 and 4, and as shown in FIGS. 5A and 5B, a portion 14A that is fused with the heat generating resistance sheet 2 and this portion 14A. May have a shape in which the line connecting the opposite side portion 14B is curved. The heat-generating composition that constitutes the covered wire 14 is the same as the heat-generating composition that constitutes the covered wire 4 of the first embodiment. That is, the heat-generating composition constituting the covered wire 14 has the thermoplastic resin and the conductive particles, the electric resistance value is 0.5 to 1000 Ω · cm, and the ratio between the maximum resistance value and the room temperature resistance value is 10. ³ or more.

In the second embodiment having such a structure, in addition to the same effect as the first embodiment, the covered wire 14 is
A portion 14A to be fused with the heat generation resistance sheet 2 and this portion 14
A portion 14B on the opposite side to A is flat, and the width dimension L ₃ of the portion 14A fused to the heating resistance sheet 2 is the width of the portion 14B opposite to the portion 14A fused to the heating resistance sheet 2. Since it is formed to be longer than the dimension L _1, when laminating the heating resistance sheet 2 and the covered wire material 14 with the exterior material 5, air is not accumulated between the exterior material 5 and the heating resistance sheet 2 and the covered wire material 14, It is possible to prevent the performance of the planar heating element 11 from deteriorating. Moreover, if the covered wire 14 has a trapezoidal cross-sectional shape, it becomes easy to manufacture a die for extruding the covered wire 14.

Next, a third embodiment of the present invention will be described with reference to FIG. The third embodiment is different from the second embodiment in that the shape of the covered wire is different, but the other configurations are the same as the second embodiment. FIGS. 6A to 6D are cross-sectional views showing different shapes of the coated wire rod of the third embodiment. In FIG. 6, the planar heating element 21 is a coating of two pieces (only one is shown in FIG. 6) formed by coextrusion molding the heating resistance sheet 2, the electrode wire group 3 and a heating composition. It is configured to include a wire rod 24 and the exterior material 5 in which the heating resistance sheet 2 and the covered wire rod 24 are laminated. Covered wire 2
As shown in FIGS. 6A and 6B, the flat plate portion 2 having a flat portion 24A that is fused with the heat generating resistance sheet 2 is shown in FIG.
4B and a shape having a tapered portion 24C which is formed integrally with the flat plate portion 24B and whose width dimension becomes shorter as it goes away from the planar portion 24A, or as shown in FIGS. 6C and 6D, There is a shape having a flat portion 24A that is fused with the heat generating resistance sheet 2 and a tapered portion 24C whose width dimension becomes shorter as the distance from the flat portion 24A increases. The covered wire rod 24 shown in FIGS.
Is a curved surface of the tapered portion 24C, and the covered wire rod 24 shown in FIGS.
The inclined surface of 4C is linear. According to the third embodiment, the same effect as the second effect can be obtained.

The present invention is not limited to the configuration of the above embodiment, but includes the following modified examples as long as the object of the present invention can be achieved. For example, in each of the above-described embodiments, the electrode wire group 3 is formed on the covered wire rods 4, 14 and 24.
However, in the present invention, the electrode wire group 3 may be provided in a plurality of steps. Further, although the two covered wire rods 4, 14 and 24 were fused to the heat generating resistance sheet 2, the covered wire rods 4, 14 and 24 were
May be three or more. Furthermore, the covered wire 4
And one end surface of the heating resistance sheet 2 are in the same plane,
Although the end portions of the portions 14A and 24A of the coated wire rods 14 and 24 that are fused to the heat generation resistance sheet 2 are aligned with the side surfaces of the heat generation resistance sheet 2, the coated wire rods 4, 14, 24 and the heat generation resistance sheet 2
The position of fusing with is not limited to this. For example, the end portions of the covered wire rods 4, 14 and 24 may be attached to the heating resistance sheet 2.
It may be shifted from the end face to the outside by a predetermined length. Further, instead of laminating the sheathing material 5 on the covered wire rods 4, 14, 24 and the heating resistance sheet 2, the covered wire rods 4, 14,
24 and the heat generating resistance sheet 2 may be sealed with a heat resistant bag.

[0030]

According to the present invention, a heat-generating resistance sheet formed by planarly molding a heat-generating composition containing a thermoplastic resin and conductive particles, and a heat-generating composition containing the thermoplastic resin and conductive particles. And a plurality of coatings formed by coextrusion molding a plurality of electrode wire groups in which a single wire of an electrode lead wire is arranged in parallel and in a flat plate shape without intersecting with each other, and are fused and separated from each other by a predetermined distance on a heating resistance sheet. Since the sheet heating element is configured by including the wire rod, the circumference of the electrode wire group can be thinned, and the electrode wire group can be easily attached to the heating resistance sheet, and the handleability is improved, and the covered wire rod is also provided. Since the heat-generating composition (1) shows an electric resistance value equal to or lower than that of the heat-generating composition of the heat-generating resistance sheet and has a positive temperature coefficient characteristic, the heat-generating resistance sheet can appropriately generate heat.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a planar heating element according to a first exemplary embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a partially cutaway perspective view of a planar heating element according to a second exemplary embodiment of the present invention.

4 is a cross-sectional view of FIG.

5 (A) and 5 (B) are cross-sectional views showing different examples of the coated wire rod of the planar heating element according to the third embodiment.

6 (A) to (D) are cross-sectional views showing a coated wire rod of a sheet heating element according to a third embodiment of the present invention.

[Explanation of symbols]

 1,11,21 Sheet heating element 2 Heating resistance sheet 3 Electrode wire group 3A Single conductor wire for electrode 4,14,24 Coated wire rod

Claims (4)

[Claims] 1. A heat-resistant sheet formed by planarizing a heat-generating composition having a thermoplastic resin and conductive particles,
A heat-generating composition having a thermoplastic resin and conductive particles and a plurality of electrode wire groups in which a single wire of a conductor for an electrode is arranged in parallel and in a flat plate shape without intersecting with each other are formed by coextrusion molding on the heat-generating resistance sheet. At least two covered wire materials which are separated from each other by a predetermined distance and are fused to each other, wherein the heat-generating composition of the covered wire material shows an electric resistance value equal to or lower than that of the heat-generating composition of the heat-generating resistance sheet, and has a positive temperature coefficient. A sheet heating element having characteristics. 2. The sheet heating element according to claim 1, wherein the covered wire has a flat portion in a portion to be fused with the heat generating resistance sheet and a portion opposite to this portion. A sheet heating element characterized in that the width dimension of the portion to be fused with the sheet is longer than the width dimension of the portion on the side opposite to the portion to be fused with the heat generating resistance sheet. 3. The sheet heating element according to claim 1, wherein the covered wire has a flat portion in a portion to be fused with the heating resistance sheet and has a width dimension fused with the heating resistance sheet. A planar heating element having a tapered portion that becomes shorter as the distance from the portion increases. 4. The sheet heating element according to claim 1, wherein the heat generating composition of the coated wire has an electric resistance value.
0.5 ~ 1000 Ωcm, and the ratio of the maximum resistance value and room temperature resistance value is 10 ³ or more, the electric resistance value of the heat generating composition of the heat generating resistance sheet is 10 ~ 50,000 Ωcm. Characteristic sheet heating element.