KR20240003107A - Plate heater - Google Patents

Abstract

The present invention relates to a planar heating heater. Specifically, the present invention can secure a large heating area even when applied to a curved surface, while providing a quick and uniform thermal sensation at low voltage and low power, preventing wrinkles from occurring even during repeated heating and cooling, and manufacturing. It relates to a planar heating heater whose cost can be minimized.

Description

Plate heater {Plate heater}

The present invention relates to a planar heating heater. Specifically, the present invention can secure a large heating area even when applied to a curved surface, while providing a quick and uniform thermal sensation at low voltage and low power, preventing wrinkles from occurring even during repeated heating and cooling, and manufacturing. It relates to a planar heating heater whose cost can be minimized.

A planar heating heater is a compact heater with electrodes and heating elements printed on a planar support plate, and is used in electrical and electronic products that require miniaturization and weight reduction, such as printers, copiers, heaters, ovens, cookers, etc., mobile devices, etc. For example, it can be applied to various purposes such as automobiles, ships, and aircraft.

In particular, planar heating heaters must be able to be applied to various curved areas depending on the application, but due to this complex application area, it is difficult to secure a large heating area or design to provide a quick and uniform thermal sensation at low voltage and low power. Additionally, there is a problem of increased manufacturing costs due to complex design.

In addition, in order to provide a quick and sufficient sense of warmth to the subject, the surface heating heater has an insulation material applied to the surface to prevent heat loss in the direction opposite to the surface facing the subject. During the repeated heating and cooling process, the heater and the insulation material Different expansion and shrinkage rates may cause problems such as wrinkles in the planar heating heater and damage to its appearance and heating function.

Therefore, even when applied to a curved surface, it can secure a large heating area and provide a quick and uniform thermal sensation at low voltage and low power, prevent wrinkles even during repeated heating and cooling, and minimize manufacturing costs. There is an urgent need for a heater that can generate surface heat.

The purpose of the present invention is to provide a planar heating heater that can provide a quick and uniform thermal sensation at low voltage and low power while securing a large heating area even when applied to a curved surface.

In addition, the purpose of the present invention is to provide a planar heating heater in which wrinkles can be prevented even during repeated heating and cooling, and manufacturing costs can be minimized.

In order to solve the above problems, the present invention,

A planar heating heater comprising a fixing plate, an insulating layer provided on an upper part of the fixing plate, an adhesive layer provided on an upper part of the insulating layer, and a film heater provided on an upper part of the adhesive layer, and the adhesive composition forming the adhesive layer has a tensile strength of 0.7 MPa or more. and provides a planar heating heater with a thermal expansion coefficient of 170×10 ^-6 m/m℃ or less.

On the other hand, the planar heating heater includes a fixing plate, an insulating adhesive layer provided on an upper part of the fixing plate, and a film heater provided on an upper insulating adhesive layer, wherein the insulating adhesive layer is formed from an insulating composition containing an insulating additive in the adhesive composition. , the adhesive composition provides a planar heating heater having a tensile strength of 0.7 MPa or more and a thermal expansion coefficient of 170×10 ^-6 m/m°C or less.

In addition, the planar heating heater includes a fixing plate, an insulating layer provided on the fixing plate, an insulating adhesive layer provided on the insulating layer, and a film heater provided on the insulating adhesive layer, and the insulating adhesive layer contains an insulating additive in the adhesive composition. It is formed from an insulating composition containing a, wherein the adhesive composition has a tensile strength of 0.7 MPa or more and a thermal expansion coefficient of 170×10 ^-6 m/m°C or less, providing a planar heating heater.

Here, the adhesive composition provides a planar heating heater, characterized in that the tensile strength is 3 to 10 MPa and the thermal expansion coefficient is 68×10 ^-6 to 75×10 ^-6 m/m°C.

In addition, the adhesive composition provides a planar heating heater, characterized in that it contains a thermoplastic resin or a thermosetting resin.

Here, the thermoplastic resin has a weight average molecular weight of 1,000 to 200,000 g/mol, and includes polyamide, polyacrylate, polymethyl methacrylate, polyvinyl chloride, and poly Characterized by comprising at least one selected from the group consisting of polypropylene, polystyrene, polytetrafluoroethylene, low-density polyethylene, and high-density polyethylene. Provides a planar heating heater.

In addition, the thermosetting resin includes one or more selected from the group consisting of epoxy resin, polyester resin, polyurethane resin, phenolic resin, and melamine resin. And, the adhesive composition is selected from the group consisting of amine-based, acid anhydride-based, imidazole-based, methyl ethyl ketone peroxide, benzoyl peroxide, tert-butyl peroxybenzoate, hexamethylene tetraamine, ammonium chloride, and free formaldehyde. It further includes at least one selected curing agent, and the weight mixing ratio of the thermosetting resin and the curing agent is 1:1 to 1:3.

Meanwhile, a planar heating heater is provided, characterized in that it additionally includes an adhesive layer provided on the film heater and a cover layer provided on the adhesive layer.

Furthermore, the insulation layer provides a planar heating heater, characterized in that it includes urethane foam or ceramic foam.

In addition, the insulation additive includes at least one hollow body selected from the group consisting of silica, silicon, alumina, and aluminum silicate.

Here, a planar heating heater is provided, characterized in that the size of the hollow body is 30 to 100 ㎛.

Furthermore, based on the total weight of the insulating adhesive layer, the content of the insulating additive is 40 to 70% by weight.

In addition, the film heater includes a base film, one or more carbon-based heating elements formed on one surface of the base film, and a pair of electrodes that are electrically connected to both ends of each of the carbon-based heating elements and have different polarities. Provides a planar heating heater.

The planar heating heater according to the present invention secures a large heating area even when a specific adhesive layer is applied between the film heater and the insulating material or is applied to a curved surface through a laminated structure in which the insulating material also performs an adhesive function, while operating at low voltage and low power. It can provide a quick and uniform sense of warmth, prevents wrinkles even during repeated heating and cooling, and has excellent effects in minimizing manufacturing costs.

Figure 1 schematically shows the laminated structure of one embodiment of a planar heating heater according to the present invention.
Figure 2 schematically shows the laminated structure of another embodiment of the planar heating heater according to the present invention.
Figure 3 schematically shows the laminated structure of another embodiment of the planar heating heater according to the present invention.
Figure 4 schematically shows the plan design of the film heater in Figures 1 to 3.
Figure 5 is a cross-sectional view taken along line AA of Figure 4.
Figure 6 is a photograph showing the results of an anti-wrinkle experiment in Example.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosure will be thorough and complete, and so that the spirit of the invention can be sufficiently conveyed to those skilled in the art. Like reference numerals refer to like elements throughout the specification.

Figure 1 schematically shows the laminated structure of one embodiment of a planar heating heater according to the present invention.

As shown in Figure 1, the planar heating heater according to the present invention includes a fixing plate 100, a heat insulating layer 200 provided on top of the fixing plate 100, and an adhesive layer 300 provided on top of the heat insulating layer 200. , a film heater 400 provided on the adhesive layer 300, etc.

The fixing plate 100 performs the function of supporting structures stacked on the fixing plate 100, and is not particularly limited as to what material it is made of as long as it has the strength and flexibility to maintain the shape of the planar heating heater, For example, it may be made of plastic materials such as polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), polystyrene (PS), and acrylonitrile butadiene styrene (ABS).

The insulating layer 200 prevents thermal energy generated by the heat generation of the film heater 400 from leaking out toward the fixing plate 100, so that the film heater 400 provides a rapid and uniform thermal sensation to the subject at low voltage and low power. It performs a function that allows it to be provided, and may include, for example, urethane foam, ceramic foam, etc.

Meanwhile, the insulating layer 200 and the adhesive layer 300 may integrally form one insulating adhesive layer, and the insulating adhesive layer may include, for example, an insulating additive in the adhesive composition forming the adhesive layer 300. The included thermal insulation composition may be formed by applying or coating.

Here, the insulating additive may include a hollow body made of a material such as silica, silicon, alumina, or ceramic such as aluminum silicate, and the hollow body exhibits an insulating effect by suppressing the movement of heat by air contained in the pores. .

The size of the hollow body may be 30 to 100 ㎛. Here, the size of the hollow body means the diameter of a complete sphere converted to have the same volume. If the size of the hollow body is less than 30 ㎛, the insulating effect of the insulation adhesive layer may be insufficient, whereas if the size of the hollow body is more than 100 ㎛, the insulating effect of the insulation adhesive layer may be insufficient. The adhesion between the insulating adhesive layer and the fixing plate 100 or the film heater 400 may decrease.

Additionally, the content of the insulating additive may be 40 to 70 wt% based on the total weight of the insulating adhesive layer. If the content of the insulation additive is less than 40% by weight, the insulation effect does not meet the standard, while if it is more than 70% by weight, the adhesive strength may be significantly reduced.

The adhesive layer 300 not only has the function of bonding the insulating layer 200 and the film heater 400 to each other, but also serves to bond the insulating layer 200, which has a relatively large thermal expansion coefficient, to the film heater 400, which has a relatively small thermal expansion coefficient. In order to solve the problem of wrinkles occurring due to the stress generated during repeated heating and cooling due to the difference in expansion and contraction rates being applied to the film heater 400, the stress is alleviated by maintaining precisely adjusted tensile strength and thermal expansion coefficient. It functions as a buffer layer.

In particular, the adhesive composition forming the adhesive layer 300 has a tensile strength of 0.7 MPa or more, preferably 3 MPa or more, for example, 3 to 10 MPa, and a thermal expansion coefficient of 170 × 10 ^-6 m/m°C or less. , Preferably, it has physical properties of 80×10 ^-6 m/m℃ or less, for example, 68×10 ^-6 to 75×10 ^-6 m/m℃, thereby functioning as a buffer layer for sufficient adhesion and prevention of wrinkles. It can be done.

The adhesive composition may be formed from an adhesive composition in which a thermoplastic resin or thermosetting resin is dissolved in a solvent. Specifically, the adhesive composition is applied in the form of a coating film on one surface of the insulation layer 200 or the film heater 100 using screen printing or an applicator, and then applied to the surface of the exposed coating film with another substrate, that is, the insulation layer 200 or After bonding the film heater 100, heat treatment is performed at 90 to 130° C. to form a structure in which the insulation layer 200 and the film heater 100 are bonded via the adhesive layer 300.

Specifically, the thermoplastic resin is polyamide, polyacrylate, polymethyl methacrylate, polyvinyl chloride, polypropylene, polystyrene, poly It contains at least one member selected from the group consisting of polytetrafluoroethylene, low-density polyethylene, high-density polyethylene, etc., and preferably contains polyacrylate. You can.

In particular, the thermoplastic resin may have a weight average molecular weight of 1,000 to 200,000 g/mol. Here, if the molecular weight of the thermoplastic resin is less than 1,000 g/mol, the adhesive strength of the adhesive layer 300 does not meet the standard and formation of a coating film may be difficult due to the low viscosity of the adhesive composition, whereas if the molecular weight of the thermoplastic resin is more than 200,000 g/mol, the adhesive strength Due to the excessively high viscosity of the composition, it may be difficult to form a film of uniform thickness.

The thermosetting resin is preferably at least one selected from the group consisting of epoxy resin, polyester resin, polyurethane resin, phenolic resin, melamine resin, etc. may include polyester resin.

A curing agent is additionally included to cure the thermosetting resin. Here, the curing agent may include amine-based, acid anhydride-based, imidazole-based, methyl ethyl ketone peroxide, benzoyl peroxide, tert-butyl peroxybenzoate, hexamethylene tetraamine, ammonium chloride, free formaldehyde, etc. there is.

The weight mixing ratio of the thermosetting resin and the curing agent may be 1:1 to 1:3, and if the weight mixing ratio of the thermosetting resin and the curing agent is less than 1:1, curing of the thermosetting resin is insufficient and the adhesive layer 300 While the adhesive strength may fall short of the standard, if the weight mixing ratio is more than 1:3, the brittleness of the adhesive layer 300 may greatly increase due to excessive curing of the thermosetting resin.

Figure 2 schematically shows the laminated structure of another embodiment of the planar heating heater according to the present invention.

As shown in FIG. 2, the planar heating heater according to the present invention may be provided with an additional adhesive layer 500 and a cover layer 600 on the film heater 400. The additional adhesive layer 500 may be made of the same material as the adhesive layer 300 and functions to bond the film heater 400 and the cover layer 600 to each other.

In addition, the cover layer 600 functions to protect the film heater 400 from external shock or pressure and may be made of an interior material of a vehicle to which the planar heating heater is applied.

Figure 3 schematically shows the laminated structure of another embodiment of the planar heating heater according to the present invention.

As shown in FIG. 3, the insulating layer 200 may include both an insulating adhesive layer 210 such as insulating paint or insulating coating and urethane foam 220. Here, the insulating adhesive layer 210 is provided between the urethane foam 220 and the film heater 400 to enable bonding and repetitive heating between the urethane foam 220 and the film heater 400, which have excellent insulating properties. And it functions as a buffer layer against thermal expansion/contraction during cooling.

FIG. 4 schematically shows the planar design of the film heater in FIGS. 1 to 3, and FIG. 5 is a cross-sectional view taken along line A-A of FIG. 4.

As shown in Figures 4 and 5, the film heater 400 is provided with one or more carbon-based heating elements 420 on a base film 410, and both ends of each carbon-based heating element 420 have different polarities. It is electrically connected to a pair of electrodes 431 and 432, and when power is applied to the electrodes 430, the carbon-based heating element 420 generates heat according to volume resistance.

The base film 410 is an insulating film to prevent short circuit between the pair of electrodes 431 and 432 and is made of polyethylene terephthalate (PET), polyimide (PI), or polyacrylonitrile. ; PAN), polyurethane (PU), silicone, polycarbonate (PC), tefron, liquid crystal polymer (LCP), poly ether ether ketone (PEEK), polyethersulphone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethyelenen napthalate (PEN), polyphenylene sulfide (PPS), polyaryle It may include a plastic film made of one or more plastic materials selected from the group consisting of polyallylate, cellulose triacetate (CTA), cellulose acetate propinonate (CAP), etc.

The electrode 430 is a pair of electrodes having different polarities and made of metal materials such as silver (Ag), copper (Cu), aluminum (Al), stainless steel (SUS), nickel (Ni), and alloys thereof. It includes (431, 432), and for example, when one electrode 431 of the pair of electrodes holds a positive electrode (+), the other electrode 432 may hold a negative electrode (-).

The electrode 430 is a metal paste applied to one side of the base film 100 by a printing technique such as screen printing, gravure printing, roll-to-roll gravure printing, comma coating, roll-to-roll comma coating, flexo, imprinting, and offset printing. It can be formed by drying and curing at 100 to 180°C after printing.

The carbon-based heating element 320 can be formed by printing and then drying a heating element composition containing a mixed binder and conductive particles, and the mixed binder is made of phenolic resin and acetal to have heat resistance even at a temperature of about 300°C. It may contain two or more types selected from the group consisting of resins, isocyanate-based resins, epoxy-based resins, etc., and the conductive particles include carbon particles and may further include metal powder.

The carbon particles may include carbon black, carbon nanotubes, graphite, activated carbon, etc., preferably carbon nanotubes and graphite. Since carbon nanotubes as the carbon particles have a large aspect ratio, a small amount of carbon nanotubes can form a sufficient heat transfer network. It not only makes it possible, but also has the effect of increasing the glass transition temperature and heat resistance of the heating element composition, and graphite makes it possible to achieve low resistance that cannot be achieved with carbon nanotubes alone.

The planar heating heater according to the present invention can secure a large heating area even when applied to a curved surface through the configuration and structure described above, and can provide a quick and uniform thermal sensation at low voltage and low power, and can provide repetitive heating and Wrinkling is prevented even when cooled, and it has an excellent effect in minimizing manufacturing costs.

[Example]

1. Manufacturing example

A planar heating heater sample with the configuration shown in Table 1 below was manufactured.

adhesive layer heat treatment temperature
(℃) insulator tensile strength
(MPa) thermal expansion coefficient
(m/m℃) Example 1 3.4 68~75×10 ^-6 130 Urethane foam Example 2 9.8 71×10 ^-6 130 Urethane foam Example 3 4.2 71×10 ^-6 90 Urethane foam Example 4 3.4 68~75×10 ^-6 130 Insulating paint (silica 50% by weight) Example 5 9.8 71×10 ^-6 130 Insulating paint (alumina 60% by weight) Comparative Example 1 3.4 68~75×10 ^-6 140 Urethane foam Comparative Example 2 4.2 71×10 ^-6 80 Urethane foam Comparative Example 3 6.1 180×10 ^-6 130 Urethane foam Comparative Example 4 0.35 92× ^10-5 130 Urethane foam Comparative Example 5 0.69 77×10 ^-5 130 Urethane foam Comparative Example 6 3.4 68~75×10 ^-6 130 Insulating paint (silica 20% by weight) Comparative Example 7 3.4 68~75×10 ^-6 130 Insulating paint (silica 80% by weight)

2. Evaluation of anti-wrinkle efficacy

Examples and Comparative Examples Each surface heating heater sample was cooled to -20°C in a freezing chamber for 1 hour, then power was applied to the heater to generate heat at 140°C for 5 minutes based on the maximum surface temperature, and then cooled to -20°C again. This process was repeated 20 times and visually observed whether wrinkles occurred on the surface of the heater. The anti-wrinkle efficacy evaluation results are shown in Table 2 and Figure 6 below.

Wrinkles
(×/○) note Example 1 × No wrinkles Example 2 × No wrinkles Example 3 × No wrinkles Example 4 × Insulation effect passed Example 5 × Insulation effect passed Comparative Example 1 ○ Damage to urethane foam occurs after heat treatment Comparative Example 2 ○ Insufficient adhesion due to low temperature Comparative Example 3 ○ Wrinkles occur due to high thermal expansion coefficient Comparative Example 4 ○ Creases occur when heated due to high brittleness. Comparative Example 5 ○ Creases occur when heated due to high brittleness. Comparative Example 6 × Insufficient insulation effect Comparative Example 7 ○ Wrinkles occur due to decreased adhesion

As shown in Table 2 and Figure 6, it can be seen that the planar heating heater of the example where the tensile strength of the adhesive layer is 3 MPa or more and the thermal expansion coefficient is 75 × 10 ^-6 m/m ℃ or less did not generate wrinkles when heating. there is.

However, it can be seen that wrinkles occur in all cases where the tensile strength does not satisfy the range of 0.7 MPa or more and the thermal expansion coefficient of 170×10 ^-6 m/m℃ or less. In addition, it can be seen that wrinkles occur when the heat treatment temperature during the heat treatment process is less than 90 degrees or exceeds 130 degrees.

In particular, in the case of the planar heating heater of Comparative Example 3, the tensile strength was 6.1 MPa, but wrinkles occurred due to the high thermal expansion coefficient, and in the case of the planar heating heaters of Comparative Examples 4 and 5, although they were characterized by a low thermal expansion coefficient, they had very low tensile strength characteristics. As a result, it can be seen that wrinkles and cracks occur when heated due to the high brittleness of the adhesive layer after heat treatment.

In addition, although the planar heating heater of Comparative Example 1 is similar in structure to the planar heating heater of Example 1, when the heat treatment temperature exceeds 130 degrees, wrinkles occur in the urethane foam due to heat damage due to the high heat treatment temperature. It can be seen that

In addition, although the planar heating heater of Comparative Example 2 has the same configuration as the planar heating heater of Example 2, when the heat treatment temperature is less than 90 degrees, wrinkles occur due to a decrease in adhesion due to non-drying and non-curing due to the low heat treatment temperature. It can be seen that this occurs.

Furthermore, although the planar heating heaters of Comparative Examples 6 and 7 have the same composition as the planar heating heater of Example 4 except for the insulating paint, the content of the insulating additive in the insulating paint is less than 40% by weight or more than 70% by weight. Otherwise, there is a problem of insufficient insulation effect or wrinkles.

This means that when the content of the insulating additive is less than 40% by weight, the overall porosity of the insulating layer is lowered due to the low insulating material content, and the content of the air layer is correspondingly lowered, so the insulating effect is insufficient, making it unsuitable for use as an insulating layer. .

In addition, when the content of the insulating material exceeds 70% by weight, it can be seen that it is difficult to secure adhesion due to the relatively low adhesive content due to the content of too much insulating additive, resulting in wrinkles.

On the other hand, the planar heating heater of Example 5 can be seen to have an insulating effect similar to that of the planar heating heater of Example 4 when 60% by weight of alumina is added to the insulating paint.

Therefore, it was confirmed that the adhesive layer used in the planar heating heater should have a tensile strength of 0.7 MPa or more and a thermal expansion coefficient of 170 × 10 ^-6 m/m℃ or less to suppress wrinkles during heat generation. In addition, it was confirmed that the content of the insulating additive in the insulating paint is suitable to be 40% by weight or more and 70% by weight or less in order to prevent the heat generated from the film heater from being transferred to the fixed layer of the insulating layer used in the planar heating heater.

Although the present invention has been described above with reference to an embodiment, those skilled in the art may make various modifications and changes to the present invention without departing from the spirit and scope of the present invention as set forth in the claims described below. You can do it. Therefore, if the modified implementation basically includes the elements of the claims of the present invention, it should be considered to be included in the technical scope of the present invention.

100: fixing plate 200: insulation layer
300: Adhesive layer 400: Film heater
500: Adhesive layer 600: Cover layer

Claims (13)

As a surface heating heater,
It includes a fixing plate, an insulating layer provided on an upper part of the fixing plate, an adhesive layer provided on an upper part of the insulating layer, and a film heater provided on an upper part of the adhesive layer,
The adhesive composition forming the adhesive layer has a tensile strength of 0.7 MPa or more and a thermal expansion coefficient of 170×10 ^-6 m/m°C or less. As a surface heating heater,
It includes a fixing plate, an insulating adhesive layer provided on top of the fixing plate, and a film heater provided on top of the insulating adhesive layer,
The insulating adhesive layer is formed from an insulating composition containing an insulating additive in the adhesive composition,
The adhesive composition has a tensile strength of 0.7 MPa or more and a thermal expansion coefficient of 170×10 ^-6 m/m°C or less. As a surface heating heater,
It includes a fixing plate, an insulating layer provided on an upper part of the fixing plate, an insulating adhesive layer provided on an upper part of the insulating layer, and a film heater provided on an insulating adhesive layer,
The insulating adhesive layer is formed from an insulating composition containing an insulating additive in the adhesive composition,
The adhesive composition has a tensile strength of 0.7 MPa or more and a thermal expansion coefficient of 170×10 ^-6 m/m°C or less. According to any one of claims 1 to 3,
The adhesive composition has a tensile strength of 3 to 10 MPa and a thermal expansion coefficient of 68×10 ^-6 to 75×10 ^-6 m/m°C. According to any one of claims 1 to 3,
The adhesive composition is a planar heating heater, characterized in that it contains a thermoplastic resin or a thermosetting resin. According to clause 5,
The thermoplastic resin has a weight average molecular weight of 1,000 to 200,000 g/mol,
Polyamide, polyacrylate, polymethyl methacrylate, polyvinyl chloride, polypropylene, polystyrene, polytetrafluoroethylene , a planar heating heater, characterized in that it includes at least one member selected from the group consisting of low-density polyethylene and high-density polyethylene. According to clause 5,
The thermosetting resin includes one or more selected from the group consisting of epoxy resin, polyester resin, polyurethane resin, phenolic resin, and melamine resin,
The adhesive composition is one selected from the group consisting of amine-based, acid anhydride-based, imidazole-based, methyl ethyl ketone peroxide, benzoyl peroxide, tert-butyl peroxybenzoate, hexamethylene tetraamine, ammonium chloride, and free formaldehyde. It additionally contains more than one type of hardener,
A planar heating heater, characterized in that the weight mixing ratio of the thermosetting resin and the curing agent is 1:1 to 1:3. According to any one of claims 1 to 3,
A planar heating heater, characterized in that it further comprises an adhesive layer provided on top of the film heater and a cover layer provided on top of the adhesive layer. According to paragraph 1,
A planar heating heater, characterized in that the insulation layer includes urethane foam or ceramic foam. According to paragraph 2 or 3,
The insulating additive is a planar heating heater, characterized in that it includes one or more hollow bodies selected from the group consisting of silica, silicon, alumina, and aluminum silicate. According to clause 10,
A planar heating heater, characterized in that the size of the hollow body is 30 to 100 ㎛. According to clause 10,
Based on the total weight of the insulation adhesive layer, the content of the insulation additive is 40 to 70% by weight. According to any one of claims 1 to 3,
The film heater includes a base film, one or more carbon-based heating elements formed on one surface of the base film, and a pair of electrodes electrically connected to both ends of each of the carbon-based heating elements and having different polarities. , planar heating heater.