WO1999026456A1

WO1999026456A1 - Planar heater and planar heat-generating body

Info

Publication number: WO1999026456A1
Application number: PCT/JP1998/005133
Authority: WO
Inventors: Kunio Tanaka; Sumio Aoki
Original assignee: Teijin Limited; Teijin Shokusan Co., Ltd.
Priority date: 1997-11-13
Filing date: 1998-11-13
Publication date: 1999-05-27

Abstract

A planar heater comprises a planar heat-generating body fabricated by extending along one surface of a planar support a twisted yarn-like electric resistor formed by twisting a fiber of an electrically conductive material and a fiber of an electrically nonconductive material and securing the resistor to the surface, a first soft cover layer covering the surface of the support to which the twisted yarn-like electric resistor is secured, and a second soft cover layer covering the surface of the support opposite to the surface to which the twisted yarn-like electric resistor is secured. The first and second cover layers are secured to each other along the edges of the planar heat-generating body and deformable independently in a region where the planar heat-generating body is provided.

Description

Description Sheet heater and sheet heating element

The present invention relates to a sheet heater, and more particularly, to a sheet heater which is tough, excellent in bending resistance and easy to manufacture, and a sheet heating element therefor. Background art

2. Description of the Related Art Conventionally, in the field of heaters, a sheet heating element in which a rubber compound in which a conductive material is kneaded is formed in a sheet shape and electrode plates are embedded at both ends thereof is known. In this planar heater, since the distribution of the conductive material dispersed in the rubber compound is uneven, the heat generation distribution is uneven, and the performance as designed is improved. I can't expect it. Also, many manufacturing processes are required, such as a kneading process for dispersing the conductive material in the rubber compound and a vulcanizing process after the rubber compound is made into a sheet. It becomes.

In addition, a sheet heater in which a heating wire whose core yarn is covered with a synthetic resin in which conductive particles such as carbon particles and metal particles are dispersed is made to creep on the surface of the substrate. Are known. In this sheet heater, the conductive layer coated around the core yarn is energized to generate heat, but the material used for this kind of conductive layer is generally an electric resistance value. Is small, and there is a problem that a sufficient amount of heat cannot be obtained. In addition, since the conductive layer made of a synthetic resin in which conductive particles are dispersed is generally low in flexibility, it is difficult to bend with a small radius of curvature, and it is forcibly bent. And the conductive layer may be peeled off. Disclosure of the invention

The present invention has been conceived in order to solve the related problems, and it is an object of the present invention to make the heating element itself thin and lightweight, but also tough and tough. It is intended to provide a sheet heater excellent in foldability and easy to manufacture.

That is, according to the present invention, a twisted electric resistor formed by stitching a fiber made of a conductive material and a fiber made of a non-conductive material is attached to one surface of a flat support. A sheet heating element extending and fixed along the first heating element; a first flexible outer covering layer covering a surface on which the twisted electric resistance element extends and is fixed on the support; There is provided a planar heater comprising: a flexible second covering layer that covers a surface on the opposite side of a surface on which the twisted electric resistor is extended and fixed. In this sheet heater, the first and second cover layers are fixed to each other along the peripheral edge of the sheet heating element, and the sheet heating element is provided. The layers are laminated so that they can be freely deformed in each area. More specifically, the first and second outer layers and the sheet heating element are in close contact with each other in a free state, but are not integrally connected and have a relatively small force, for example, It can be easily separated with just enough force to be applied manually.

In this planar heating element, since the twisted electric resistor itself has flexibility, even if it is bent with a small radius of curvature, the twisted electric resistor may be broken or cut. This is rare.

Preferably, the support is a base film, and the twisted electric resistance is extended and sewn to meander along one surface of the base film. In this sheet heating element, the thickness of the sheet heating element itself is small because the base film is flexible and the twisted electric resistor is sewn and fixed. It is thin and lightweight. In addition, it is easier and more efficient to sew and fix twisted electric resistors with an industrial sewing machine. And can be done.

As the base film, a polyster film having excellent heat resistance and insulation properties is preferably used.

The conductive fiber is made of a finite length stainless steel fiber, the non-conductive fiber is made of a finite length polyamide fiber, and the stranded electric resistance is The body can contain from 20 to 80% by weight of the stainless steel fiber and from 80 to 20% by weight of the polyamide fiber. By selecting an appropriate value, a desired volume resistivity can be obtained.

Further, the base film is made of a material that is incompatible with the first jacket layer, and covers a surface of the base film on which the yarn electrical resistor extends and is fixed. The first cover film is made of a material that is incompatible with the second cover layer, and the first force film is formed on the base film. A second cover fin can be provided to cover the surface opposite to the surface covered by the cover.

Furthermore, by connecting a plurality of serial wiring circuits in parallel and forming electrode terminals at both ends of each circuit, the surface heating element can have a desired predetermined area. You. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a plan view including a partial cross section of a planar heater according to the first embodiment of the present invention.

FIG. 2 is a plan view including a partial cross section of the planar heating element according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view of the sheet heating element of FIG.

FIG. 4 is an explanatory view showing the structure of the twisted electric resistor.

FIG. 5 is a cross-sectional view taken along the line V--V in FIG. FIG. 6 is a plan view including a partial cross section of the sheet heating element according to the second embodiment of the present invention.

FIG. 7 is a plan view including a partial cross section of a planar heating element according to the third embodiment of the present invention.

FIG. 8 is a partial sectional view taken along the line V 1 H-VIII in FIG. 7, and FIG. 9 is a side view of the twisted electric resistor according to the fourth embodiment of the present invention.

FIG. 10 is a partial cross-sectional view of a planar heater according to the fifth embodiment of the present invention.

FIG. 11 is a partial cross-sectional view of a planar heater according to the sixth embodiment of the present invention.

FIG. 12 is a partial cross-sectional view of a planar heater according to a seventh embodiment of the present invention.

FIG. 13 is a partial cross-sectional view of the planar heater according to the eighth embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First, a planar heater according to a first embodiment of the present invention will be described with reference to FIG. 1 to FIG. As shown in FIG. 1, the sheet heater 100 is made up of a sheet heating element 10, and first and second covering layers 100 2 covering both surfaces of the sheet heating element 10. , 104. The first and second jacket layers can be formed from a flexible, non-conductive material, preferably a synthetic rubber.

As shown in FIGS. 2 and 3, the sheet heating element 10 includes a band-shaped base film 11 and a twisted electric resistance attached to one surface of the base film 11. And the body 12. The twisted electric resistor 1 2 is It extends along a meandering path on one surface of the lum 11 and is sewn to the base film 11 by a fastening thread 17. In addition, the surface of the base film 11 on which the twisted electric resistors 12 are provided is covered with the first canopy film 14 and the opposite surface. Is covered by a second cover film 15.

The twisted electric resistor 12 can be easily and efficiently used, for example, by using an industrial machine with the twisted electric resistor 12 as the upper thread and the fastening thread 17 as the lower thread. It can be sewn to film 11.

As shown in FIG. 4, the twisted electric resistor 12 is formed by staggering a discontinuous fiber 21 made of a conductive material and a discontinuous fiber 22 made of a non-conductive material. It has been done. The preferred and rather, conductive discontinuous fibers 2 1, that Yusuke and 1 0 one ^{^{5 ~ 1 0 _ 6 Ω ·}} cm volume resistivity of O over loaders, and diameters in the range of 4 ~ 3 0 m It can be obtained by drawing stainless steel filaments to a specified length. Stainless steel fibers with a diameter greater than 3

It is not preferred because of low flexibility.

Also, the conductive discontinuous fibers 21 preferably have an average fiber length of 100 nm! It has a length in the range of ~ 800 mm. When the average fiber length is less than 100 mm, the number of contact points between the conductive discontinuous fibers 21 in the twisted electric resistor 12 decreases and becomes unstable, resulting in uniform electric power. This causes a problem that the resistance value cannot be obtained. On the other hand, when the length of the conductive discontinuous fiber 21 exceeds 800 mm, the number of contact points between the conductive discontinuous fibers 21 decreases, and the electrical resistance value decreases. There is a problem that the volume resistivity cannot be obtained.

Conductive discontinuous fibers 2 1 nonconductive to blended discontinuous fibers 2 2 (see FIG. 4), and the this volume resistivity of that is that to form et or 1 0 ^{1 2} Omega · cm or more materials Specifically, synthetic fibers, regenerated fibers, and natural fibers can be used. In particular, wholly aromatic polyamides have high heat resistance Therefore, it is preferable that the electric resistance is not deteriorated or ignited by the temperature rise due to the heat generation of the twisted electric resistor 12. In addition, as heat-resistant fibers, fibers made of heat-resistant polymers such as polybenzimidazole, polyimid, and polyetheretherketone can be used. It is.

In the twisted electric resistor 12, the conductive discontinuous fiber 21 has an arbitrary spinning ratio of 20 to 80 weight of the total weight of the yarn and is perpendicular to the central axis of the twisted electric resistor 12. The conductive discontinuous fibers 21 and the non-conductive discontinuous fibers 22 are blended so that 20 or more fibers are included in the cross section. If the number of conductive discontinuous fibers 21 is less than 20, it is difficult to increase the number of contact points between the conductive discontinuous fibers 21 to a desired number or more, and a uniform volume resistivity value is obtained. Powers that are difficult to obtain.

Note that the twisted electric resistor 12 composed of the conductive discontinuous fiber 21 and the non-conductive discontinuous fiber 22 is, for example, a long fiber of stainless steel and an aromatic aromatic polyester. The non-conductive fibers made of mid are drawn together and stretched several times to several tens times to perform the traction, and then the compressed air nozzle is used. It can be formed by entangled into a fiber bundle. The details of such a process are disclosed, for example, in Japanese Patent Application Laid-Open No. HEI 4-19040 and Japanese Patent Publication No. Hei 5-718157. Is referred to as an integral part of the present specification.

It is preferable that the twisted electric resistor 12 is provided with lower combustion having a twist coefficient K, in the range of 6500 to 1350. When the twisted electric resistor 12 is formed by entanglement using the above-described pressurized air nozzle, it is necessary to add a priming separately. When the twist coefficient K, is less than 650, the rate of change of the volume resistivity of the heating element code is large. On the other hand, when the twist coefficient, i. This increases torque and reduces handleability, which is not preferred. Where the twist coefficient K is

Κ = Τ / Μ (number of twists per meter) X ^ (Defined by yarn total De ... (1).

The twisted electric resistor 12 is preferably further provided with an upper twist in a direction opposite to the lower twist. The twisting coefficient K ₂ needs to satisfy the above equation (1). Here, the balance between the ply twist and the ply twist of the twisted electric resistor 12 is particularly important. In other words, thermoplastic fibers such as synthetic fibers are usually twisted to prevent twisting, but twisted yarns containing stainless steel fibers are used as conductive discontinuous fibers. In the electrical resistor 12, the balance of the twist is important because it is not possible to carry out the heat setting.

Practically, it is preferable that the volume specific resistance value of the twisted electric resistor 12 be in the range of 0.5 to 10 Ω ♦ cm. If the volume resistivity of the twisted electric resistor 12 exceeds 10 Ω · cm, a sufficient heat generation density cannot be obtained, while if it is less than 0.5 Ω · cm, the heat generation density becomes excessive. Further, with the twisted electric resistor 12, the coefficient of variation of the resistance value C V% can be reduced, and a C V 10 (%) can be obtained.

Further, as the fastening yarn 17, it is preferable to use a fiber of the same system as the non-conductive fiber mixed with the twisted electric resistor 12. Further, the base film 11 and the first and second cover films 14a and 14b can be formed from a poly ster film having excellent insulation properties. It is possible. The sheet heating element 10 thus formed is applied with a voltage between both ends 15 and 16 of the twisted electric resistor 12 by an appropriate power supply device (not shown). As a result, the twisted electric resistor 12 generates heat.

In FIG. 1, the sheet heater 100 is provided with two sheet heating elements 10 arranged in parallel, and the sheet heating element 10 is provided with a twisted electric resistor 12 in the sheet heating element 10. The first covering layer 10 2 covering the surface and the planar heating element 10 And a second covering layer 104 covering the surface on the opposite side of the surface on which the twisted electric resistor 12 is provided. The sheet heater 100 may include one sheet heating element 10. Furthermore, by arranging three or more sheet heating elements 10 in parallel, the area of the heater 100 can be enlarged to a desired size. You. In this case, the terminals 15 and 16 of the sheet heating element 10 are connected to the electrode terminals 106 and 108, and a parallel circuit is formed by the plurality of sheet heating elements 10. However, a configuration in which a plurality of sheet heating elements 10 are connected in series to form one unit and these units are connected in parallel with each other also constitutes a parallel circuit as a whole. You can see it. Therefore, such a configuration is also included in the present invention.

The first and second outer layers 102, 104 are formed of a flexible synthetic rubber, and are formed by a well-known technique such as thermocompression bonding. They are fixed to each other along the periphery. Referring to FIG. 5, area I indicates an area where the sheet heating element 10 is provided. The region 11 is a region where the first and second outer layers 100 2 and 104 are connected to the body at the peripheral portion of the sheet heater 100. Hereinafter, the peripheral button This is called the storage area. The region III is a region in which the first and second outer layers 102 and 104 are connected to the body between the sheet heating elements 10 and is hereinafter referred to as an intermediate bond region. .

As described above, the canopy films 14a and 14b can be formed, preferably by a polyester film. The polystyrene film is shown in FIG. 5 because it is not compatible with the synthetic rubber material forming the first and second outer layers 102, 104. In the region I, that is, at the boundary surface between the planar heating element 10 and the first and second outer coating layers 102 and 104, the first and second canopy layers are manually formed. Attach to the first and second cover films 14a, 14b to such an extent that they can be easily peeled off from the one finale 14a, 14b. This state is the state of the surface heater 100 A small piece is cut by cutting the area I where the linear heating element 10 is present so as not to include the peripheral bond area II or the intermediate bond area III at a square of about 10 cm. Then, the first and second outer layers 102 and 104 of the small piece stably adhere to the sheet heating element 10 stably in a free state where no force is applied. It was confirmed that each jacket layer could be easily peeled off by manual operation.

As described above, since the first and second cover layers 102 and 104 can be easily separated from the sheet heating element 10, the flexibility of the sheet heater 100 can be improved. For example, it is possible to roll the sheet-shaped surface 100 in a roll shape for transportation and storage. This is because, when the sheet heater 100 is curved, the first and second cover layers 102 and 104 become the first and second cover films 1 and 2. It is considered that this is because each of the coating layers can be deformed independently, being microscopically separated from 4a and 14b.

On the other hand, in the peripheral bond region II and the intermediate bond region III, the first and second outer cover layers 102 and 104 are firmly connected to each other, so that a planar state is obtained. The strength of the heater 100 is increased, the shape is maintained, and the durability is enhanced.

As described above, according to the first embodiment of the present invention, since the twisted electric resistor 12 itself has flexibility, even if it is bent with a small radius of curvature, the twisted electric resistor is used. The spouse body 1 2 does not break or cut.

Further, since the sheet heating element 10 is obtained by sewing and fixing a soft twisted electric resistor on one surface of the base film 11, the sheet heating element 10 is formed. 0 is thin and lightweight.

In the first embodiment, the sheet heater 100 includes a plurality of sheet heating elements 10, but is replaced with a single sheet heating element 30 shown in FIG. 6. You can also do it.

The planar heating element 30 according to the second embodiment of the present invention includes a base film. 36, a plurality of twisted electric resistors 12 extending along a plurality of meandering paths on one surface. The electric resistor 12 can be sewn to the base film 36 as shown in FIG. The plurality of electric resistors 12 are connected in parallel by leads 42a and 42b. The surface of the sheet heating element 30 on which the electric resistor 12 is provided is covered with the first cover film 38, and the electric resistor 12 on the opposite side is provided. The other side is covered by the second cover film 34. A slit 40 extending through the first cover film 38, the base film, and the second cover film 34 is provided between the plurality of electric resistors 12. It is formed.

The sheet heater (not shown) having the sheet heating element 30 is made of a material for forming the first and second jacket layers on the slit 40, for example, a synthetic rubber. Enter and are connected to each other, and perform the same operation as the intermediate band region III (see FIG. 5) in the first embodiment.

Next, a third embodiment of the present invention will be described with reference to FIGS. The third embodiment is similar to the first and second embodiments except that a lattice-shaped support is used instead of the base films 12 and 36 in the first and second embodiments. The configuration is the same as that of the second embodiment. That is, the planar heating element 50 according to the third embodiment is a twisted electric resistance element that is extended and fixed along a meandering path on one surface of the lattice-shaped support body 52. It has 1 2. The electric resistor 12 is fastened to the support 52 by a fastening thread 58. The support 52 is formed in a lattice shape from a synthetic resin having flexibility and heat resistance. The surface of the support 52 on which the electric resistor 12 is provided is covered by the first cover film 54, and the opposite surface is covered by the second cover film 54. Covered with film 56. As in the first and second embodiments, the first and second cover fins 54 and 56 are provided with the first and second cover layers 1 and 2 of the sheet heater 100. 0 2, 1 For example, it is formed from a synthetic resin material that is incompatible with synthetic rubber, for example, a polyester.

In the above-described embodiment, the bare twisted electric resistor 12 is used, but as shown in FIG. 9, a protective layer is provided on the surface of the twisted electric resistor 12. May be. That is, in the fourth embodiment, the twisted electric resistor 12 includes a double insulating layer 62 made of a synthetic resin insulating material, and a heat-resistant synthetic fiber round braid. It is covered with a covering layer 64 composed of the above. The insulating layer 62 is preferably formed of a polyvinyl chloride, and the outer layer 64 is formed of a monofilament such as polyester, polyamide, or polyether. And, more preferably, monofilament cartridges made of Polyester.

Next, a fifth embodiment of the present invention will be described with reference to FIG. The sheet heater 200 according to the fifth embodiment includes the sheet heating elements 10; 30; 50 according to any one of the first to third embodiments. A first outer coating layer 112 covering the surface of the sheet heating element 10; 30; 50 on which the twisted electric resistor 12 is provided; and a twisted electric resistor 1 provided. A second jacket layer 114 covering the uncovered surface, wherein the second jacket layer 114 is thicker than the first jacket layer 112. In addition, the heat generated in the planar heat generators 10; 30; 50 is transferred to the first envelope layer 112 more.

Next, a sixth embodiment of the present invention will be described with reference to FIG. The planar heater 300 according to the sixth embodiment is formed substantially in the same manner as the planar heater 200 of the fifth embodiment, and the first to third planar heaters are formed. The planar heating element 10; 30; 50 according to any one of the embodiments, and the twisted electric resistance element 12 are provided in the planar heating element 10; 30; 50. A first cover layer that covers the surface on which the twisted electric resistor 1 is not provided; and a second cover layer 114 that covers the surface on which the twisted electric resistor 1 is not provided. However, due to the force, the sheet heater 300 according to the sixth embodiment has a heat between the first cover layer 112 and the sheet heating element 103; 50. A heat conductive layer 310 made of a material having high conductivity, for example, a metal such as aluminum is provided. As a result, the amount of heat transferred to the first jacket layer 112 is made uniform.

Next, a seventh embodiment of the present invention will be described with reference to FIGS. The planar heater 400 according to the seventh embodiment is formed substantially identical to the planar heater 200 of the fifth embodiment, and the first to third planar heaters are similar to the planar heater 200 according to the fifth embodiment. The sheet heating element 10; 30; 50 according to any one of the embodiments and the sheet heating element 10; 30; 50; A first outer covering layer that covers the surface on which the electric power is supplied, and a second outer covering layer that covers the surface on which the twisted electric resistor is not provided. However, the sheet heater 400 according to the seventh embodiment has a temperature between the second jacket layer 114 and the sheet heating elements 10; 30; 50. A sensor 410 is provided, which can detect abnormal heat generation and cut off the current to improve safety.

Further, an eighth embodiment of the present invention will be described with reference to FIG. The planar heater 500 according to the eighth embodiment is formed substantially the same as the planar heater 200 of the fifth embodiment, and the first to third planar heaters are the same. The sheet heating element 10; 30; 50 according to any one of the embodiments and the sheet heating element 10; 30; 50; A first jacket layer 112 covers the surface on which the twisted electric resistor 12 is not provided, and a second jacket layer 114 covers the surface where the twisted electric resistor 12 is not provided. However, the sheet heater 500 according to the eighth embodiment has a force kit 5110 bonded or bonded to the outer surface of the first jacket layer 112. It is attached using known methods such as thermocompression bonding. In FIG. 13, the force unit 510 is formed by implanting the pile 514 on the fabric 521, It may be formed of an object, a nonwoven fabric, or the like.

In the embodiment of FIGS. 11 to 13, the first outer layer 112 is formed thinner than the second outer layer 114, but the first and second outer layers 111 are different from each other. The outer layers 1 12 and 1 14 may have the same thickness.

Claims

The scope of the claims

1. In the area heater,

A twisted electric resistor formed by stitching a fiber made of a conductive material and a fiber made of a non-conductive material is extended along one surface of a planar support and fixed. A planar heating element

A first flexible jacket layer that covers a surface on which the twisted electric resistor extends and is fixed on the support;

A flexible second covering layer that extends on the support and covers the surface opposite to the fixed surface of the twisted electric resistor,

The first and second jacket layers are fixed to each other along the periphery of the planar heating element, and are free to each other in a region where the planar heating element is provided. Planar heaters that are stacked so that they can be deformed.

2. The support is a base film, and the twisted electric resistance is extended and sewn so as to meander along one surface of the base film. A sheet heater according to item 1.

3. The planar heater according to claim 2, wherein the base film is made of a synthetic resin material having a melting point of 200 ° C. or more.

4. The planar heater according to claim 3, wherein the base film is a polyester.

5. The support according to claim 1, wherein the support is a lattice-shaped member, and the twisted electric resistor is extended and sewn so as to meander along one surface of the lattice-shaped member. The described planar heater.

6. The sheet heating element is made of a material that is incompatible with the first jacket layer, and the yarn electric resistor is extended and fixed on the support. The planar heater according to any one of claims 2 to 5, further comprising a first cover film that covers the surface.

7. The planar heating element is made of a material that is incompatible with the second cover layer, and is formed on a surface of the support covered with the first cover film. The planar heater according to claim 6, further comprising a second cover film that covers the opposite surface.

8. The planar heater according to claim 5, wherein the cover film is made of a synthetic resin material having a melting point of 200 ° C. or more.

9. The conductive fiber is made of a finite length stainless steel fiber, the non-conductive fiber is made of a finite length polyamide fiber, and the twisted electric resistor is made of a finite length. 20 to 80% by weight of the stainless steel fiber, and 80 to 2% by weight.

Five

The planar heater according to any one of claims 1 to 8, comprising 0% by weight of the polyamide fiber.

10. The sheet heater includes a plurality of sheet heating elements, and the twisted filaments are extended and fixed to the respective supports of the plurality of sheet heating elements, and The planar heater according to any one of claims 1 to 9, wherein the planar heater is electrically connected in parallel.

11. The planar heating element includes a plurality of twisted electric resistors extending along one surface of the support, and the plurality of twisted electric resistors are connected in parallel with each other. The planar heater according to claim 1, wherein:

12. The support is a base film, and the twisted electric resistor is meanderingly extended and sewn along one surface of the base film. 11 The surface condition described in 1 above.

13. The planar heater according to claim 12, wherein the base film is made of a synthetic resin material having a melting point of 200 ° C. or more.

14. The planar heater according to claim 15, wherein the base film is a polyester.

15. The sheet heating element is made of a material that is incompatible with the first jacket layer, and the yarn electric resistor extends and is fixed on the support. The planar heater according to any one of claims 11 to 14, further comprising a first cover film that covers a defined surface.

16. The planar heating element is made of a material that is incompatible with the second covering layer, and is covered with the first cover film on the support. The planar heater according to claim 15, further comprising: a second cover film that covers a surface opposite to the curved surface.

17. The first heating film, the base film, and the second covering film are disposed between the plurality of twisted electric resistors 12 in the planar heating element. 17. The planar heater according to claim 16, comprising a plurality of slits penetrating the film.

18. The planar heater according to any one of claims 1 to 17, wherein the twisted electric resistor includes a protective layer provided on an outer surface.

19. The protective layer comprises: an insulating layer made of a synthetic resin insulating material; and a coating layer made of a heat-resistant synthetic fiber round braid. The sheet heater described in the above section.

20. The planar heater according to any one of claims 1 to 19, wherein the first jacket layer is formed thinner than the second jacket layer.

21. The sheet heater according to any one of claims 1 to 19, further comprising a heat transfer layer between the first jacket layer and the sheet heating element.

22. The sheet heater according to any one of claims 1 to 21, further comprising a semiconductor layer between the sheet heating element and the second jacket layer.

23. The planar heater according to any one of claims 1 to 22, wherein a force cutout is provided on an outer surface of the first jacket layer.

2 4. In the planar heating element,

A planar support and

A fiber made of a conductive material and a fiber made of a non-conductive material, which are extended and fixed along one surface of the support, are formed by joining together fibers. A sheet heating element comprising: a twisted electric resistor.

25. The support is a base film, and the twisted electric resistance is extended and sewn so as to meander along one surface of the base film. Item 24. The sheet heating element according to item 24.

26. The sheet heating element according to claim 25, wherein the base film is made of a synthetic resin material having a melting point of 200 ° C or more.

27. The sheet heating element according to claim 25, wherein the base film is a polyester.

28. The planar heating element according to claim 24, wherein the support is formed in a lattice shape.

29. A first cover film covering the surface of the base film on which the thread electric resistor is extended and fixed, and the base film, 26. The sheet heating element according to claim 25, further comprising a second cover film covering a surface opposite to the surface covered with the first cover film.

30. The sheet heating element according to claim 29, wherein the cover film is made of a synthetic resin material having a melting point of 200 ° C or more.

3 1. The conductive fiber is made of stainless steel fiber of finite length, the non-conductive fiber is made of polyamide fiber of finite length, and the twisted electric wire is used. The resistor may comprise 20 to 80% by weight of the stainless steel fiber and 80 to 80% by weight.

The planar heating element according to any one of claims 24 to 30, comprising 20% by weight of the polyamide fiber.

32. A plurality of sheet heating elements are provided, and the twisted string resistors are extended and fixed to respective supports of the sheet heating elements, and are electrically connected in parallel to each other. The planar heating element according to any one of claims 24 to 31, wherein the heating element is a sheet heating element.

33. The planar heating element extends along one surface of the support 25. The sheet heating element according to claim 24, comprising a plurality of twisted electric resistors, wherein the plurality of twisted electric resistors are connected in parallel with each other.

34. The support is a base film, and the twisted electric resistors are extended and sewn so as to meander along one surface of the base film. Item 31. The sheet heating element according to item 31.

35. The sheet heating element according to claim 34, wherein the base film is made of a synthetic resin material having a melting point of 200 ° C or more.

36. The planar heating element according to claim 35, wherein the base film is a polyester.

37. A first cover film that covers the surface of the base film on which the thread electric resistor extends and is fixed, the base heating film; 32. The sheet heating element according to claim 31, further comprising a second cover film covering a surface of the film opposite to a surface covered with the first cover film.

38. The planar heating element penetrates through the first cover film, the base film, and the second cover film between the plurality of twisted electric resistors. 36. The sheet heating element according to claim 35, comprising a plurality of slits.

39. The sheet heating element according to any one of claims 24 to 38, wherein the twisted electric resistor includes a protective layer provided on an outer surface.

40. The protective layer according to claim 39, wherein the protective layer comprises: an insulating layer made of a synthetic resin insulating material; and a jacket layer made of a synthetic fiber round braid having heat resistance. Sheet heating element.