KR102361220B1 - Method for manufacturing a highly conductive carbon fiber paper, carbon fiber paper manufactured using the same, and carbon fiber plane heating element including the carbon fiber paper - Google Patents

Abstract

The present invention relates to a method for producing a carbon fiber paper in which the process is simplified by using a dispersion solution having a controlled dispersant content, and to a carbon fiber planar heating element comprising the carbon fiber paper and carbon fiber paper prepared according to the process, in particular, the carbon The manufacturing method of fiber paper is a method of mixing a dispersion solution in which carbon fibers are dispersed and a dispersion solution in which a binder is dispersed, thereby simplifying the process, so that carbon paper fibers can be easily manufactured.

Description

Method for manufacturing a highly conductive carbon fiber paper, and carbon fiber planar heating element including the carbon fiber paper and carbon fiber paper manufactured thereby heating element including the carbon fiber paper}

The present invention relates to a method for producing a high-conductivity carbon fiber paper, and to a carbon fiber planar heating element comprising the carbon fiber paper and carbon fiber paper produced thereby, and more particularly, the process is performed using a dispersion solution having a controlled dispersant content. It relates to a simplified method for producing carbon fiber paper, and to a carbon fiber planar heating element comprising the carbon fiber paper and carbon fiber paper produced thereby.

Recently, the development of a planar heating element using the self-resistance of carbon is actively in progress. A general planar heating element uses radiant heat generated when energized, and the air in the heating space is not polluted, so it is hygienic, temperature control is easy, there is no noise, and has the advantages of emitting far-infrared rays beneficial to the human body, such as apartments and pensions. It is widely used from heating materials for residential purposes to commercial, agricultural and various industrial heating materials. As a heat source of such a planar heating element, it can be classified into a metal heating element, such as aluminum, and a non-metal heating element using a carbon material.

In the case of a conventional planar heating element, a conductive material having a certain resistance, such as carbon, is applied to the insulator in a predetermined pattern, just as carbon powder is applied on an insulating film in the form of paste, and an electric current is applied thereto to generate heat. Although there is a planar heating element, such a planar heating element has a problem in that the heating temperature is not uniform, and it is difficult to use it at a high temperature. In addition, there is a planar heating element in the form of a fabric in which a resistance wire such as a carbon wire or a nichrome wire is woven together with a fiber, but there is a disadvantage that the entire heating wire is not heated when the heating wire is short-circuited. And, in the case of a planar heating element using PVA (polyvinyl alcohol) and carbon powder among carbon materials, there is a problem with the uniformity of coating thickness of PVA, etc., and it is also a factor of heat efficiency and product defects according to the difference in power density.

Accordingly, research and development of a planar heating element using a new carbon fiber nonwoven fabric is being made a lot. These carbon fiber nonwoven fabrics include low melting point fiber and carbon fiber composite nonwoven fabric (Korean Patent Publication No. 2008-0030411), pulp and carbon fiber composite nonwoven fabric (Korea Patent Publication No. 2002-0005166), conductive polymer coated carbon fiber nonwoven fabric (made in US) 2007/0028767) and the like. However, the carbon fiber nonwoven fabric using the existing polymer or non-conductive fiber and pulp as a binder has lower conductivity and heat generation performance than the conductive polymer coated carbon fiber nonwoven fabric, and the conductive polymer coated carbon fiber nonwoven fabric has a small sheet resistance, so it has excellent heating performance, etc. There is a problem that the manufacturing cost is high.

Republic of Korea Patent Publication No. 10-2002-0005166 Republic of Korea Patent Publication No. 2002-0005166 US Patent Publication No. 2007/0028767

The present invention is to solve the above problems, a method for producing a highly conductive carbon fiber paper in which the process is simplified using a dispersion solution with a controlled dispersant content, and carbon fiber paper and carbon containing carbon fiber paper prepared accordingly To provide a fiber planar heating element.

In order to achieve the above object,

In one embodiment of the present invention,

preparing a dispersion solution;

Dispersing and mixing carbon fibers and a binder in a dispersion solution containing a dispersant;

forming a carbon fiber web by vacuum filtering the dispersion solution in which carbon fibers and binders are dispersed to filter the carbon fibers; and

Drying the carbon fiber web; includes,

The content of the dispersant provides a method for producing carbon fiber paper, characterized in that the average of 0.2 to 1% by weight based on the total weight of the dispersion solution.

In addition, in one embodiment of the present invention,

It is produced by the method for producing the carbon fiber paper,

It provides a carbon fiber paper, characterized in that the average heating temperature is 70 ℃ or more, the thermal conductivity is 1 W / mk or more.

In addition, in one embodiment of the present invention,

the carbon fiber paper;

a pair of metal electrodes positioned on two parallel sides of the carbon fiber paper; and

It provides a carbon fiber planar heating element comprising; an insulating sheet attached to at least one surface of the carbon fiber.

According to the method of manufacturing carbon fiber paper according to an embodiment of the present invention, the carbon fiber paper can be easily manufactured by simplifying the process by mixing the dispersion solution in which carbon fibers are dispersed and the dispersion solution in which the binder is dispersed. have.

Furthermore, the high-conductivity carbon fiber paper thus prepared can be used for the planar heating element.

1 is a flowchart of a method for manufacturing carbon fiber paper according to an embodiment of the present invention.
Figure 2 is a schematic view of a carbon fiber planar heating element comprising a carbon fiber paper according to an embodiment of the present invention.
3 is a photograph showing the dispersion solutions prepared in Examples of the present invention, respectively.
4 is a graph showing the tensile strength of the carbon fiber paper prepared in Examples 1-5 and Comparative Examples.
5 is a graph showing the sheet resistance of the planar heating element comprising the carbon fiber paper prepared in Examples 1-5 and Comparative Examples.
6 is a graph showing the thermal conductivity of the planar heating element comprising the carbon fiber paper prepared in Examples 1-5 and Comparative Examples.
7 is a graph showing the surface heating temperature of the planar heating element comprising the carbon fiber paper prepared in Examples 1-5 and Comparative Examples.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description.

However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise.

In the present invention, terms such as "comprises" or "have" are intended to designate that the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification exist, but one or more other features It should be understood that this does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

The present invention relates to a method for producing carbon fiber paper, and to a carbon fiber planar heating element comprising the carbon fiber paper and carbon fiber paper produced thereby, and more particularly, the process is simplified by using a dispersion solution having a controlled dispersant content It relates to a carbon fiber planar heating element comprising a method for producing carbon fiber paper, and carbon fiber paper and carbon fiber paper produced thereby.

In particular, according to an embodiment of the present invention, carbon paper fibers can be easily manufactured by simplifying the process by mixing a dispersion solution in which carbon fibers are dispersed and a dispersion solution in which a binder is dispersed with each other.

Furthermore, the carbon fiber paper thus prepared can be used for the planar heating element. In particular, the carbon fiber paper and the planar heating element may have low resistance and high tensile strength.

Hereinafter, the present invention will be described in detail.

1 is a flowchart of a method for manufacturing carbon fiber paper according to an embodiment of the present invention.

Referring to FIG. 1 , the method for manufacturing carbon fiber paper according to an embodiment of the present invention includes dispersing carbon fibers and a binder in a dispersion solution containing a dispersing agent (S100); Forming a carbon fiber web by vacuum filtering the carbon fiber and the binder dispersed dispersion solution to filter the carbon fiber (S200); and drying the carbon fiber web (S300), wherein the content of the dispersant is an average of 0.2 to 1% by weight based on the total weight of the dispersion solution.

First, the step of dispersing the carbon fiber and the binder in the dispersion solution (S100) will be described in detail.

Dispersing the carbon fibers and the binder in the dispersion solution (S100), dispersing the carbon fibers in the dispersion solution (S110); dispersing the binder in the dispersion solution (S120); and mixing the dispersion solution in which the carbon fibers are dispersed and the dispersion solution in which the binder is dispersed (S130); includes That is, in the method of manufacturing carbon fiber paper according to an embodiment of the present invention, the carbon fiber and each dispersion solution in which the binder is dispersed are mixed with each other, which simplifies the process, so that the carbon paper fiber can be easily manufactured.

The dispersing agent is guar gum, arabic gum, Xtanthan gum, methyl cellulose (MC), carboxymethyl cellulose (CMC) and hydroxyethyl cellulose (Hydroxyethyl). cellulolse, HEC)) may be one or more selected from the group consisting of, for example, the dispersant may be cellulose (Carboxymethyl cellulose, CMC).

Since the dispersion solution contains the above-described dispersing agent, the viscosity of the dispersion solution can be increased, and the dispersibility of carbon fibers can be increased due to the increased viscosity. In other words, when a carbon fiber web is made through filtering because aggregation between carbon fibers is significantly reduced in the carbon fiber dispersion solution, the amount of individual carbon fibers is high, so sheet resistance can be reduced.

Meanwhile, the content of the dispersant may include an average of 0.2 to 1% by weight based on the total weight of the dispersion solution. Specifically, the dispersant may contain an average of 0.2 to 1% by weight, 0.4 to 0.9% by weight, or an average of 0.8% by weight based on the total weight.

If the dispersant contains less than 0.1% by weight based on the total weight of the dispersion solution, the fluidity of the carbon fibers may be deteriorated, and cutting of the carbon fibers may occur when the solution is stirred or moved. In addition, when the dispersant is less than a predetermined content, the tensile strength of the carbon fiber paper to be produced may also be reduced. In addition, when the dispersant exceeds 1% by weight based on the total weight of the dispersion solution, tensile strength may be increased, but it is not preferable because sheet resistance also increases. Therefore, the content of the dispersant preferably includes an average of 0.2 to 1% by weight based on the total weight of the dispersion solution, as described above.

Specifically, the dispersing agent may be dispersed in distilled water, and carbon fibers and the binder may be respectively dispersed in a solution containing the dispersant.

Carbon fibers may be PAN-based (polyacrylonitrile-based), pitch-based, rayon-based, as well as fibrous, high-carbon-containing materials. For example, the carbon fiber may be a PAN-based non-sizing carbon fiber.

Meanwhile, the content of the carbon fiber may include an average of 0.01 to 0.05% by weight, or an average of 0.3% by weight, based on the total weight of the dispersion solution. If the carbon fiber is less than 0.01% by weight based on the total weight of the dispersion solution, a lot of fiber cutting occurs and the strength of the carbon fiber paper to be produced may decrease, and if it exceeds 0.05% by weight, carbon fiber The aggregation phenomenon may occur, and the uniformity may be lowered. Accordingly, the carbon fiber content may be in the above-mentioned range.

These carbon fibers may be ?h of a predetermined length. Although the carbon fiber itself can also be subjected to resistance heating, the carbon fiber chop can generate heat even at a lower voltage by forming numerous contact points. In general, carbon fiber chop is carbon fiber cut to an appropriate length, and in consideration of conductivity, strength, dispersibility, etc., carbon fiber chop with a length of 2 to 15 mm can be used, for example, carbon fiber having an average of 6 mm ? h can be used. When the fiber length of the carbon fiber is increased, conductivity and strength are improved, whereas when the fiber length of the carbon fiber is too long, the dispersibility of the carbon fiber may be deteriorated. In addition, when the fiber length is too short, the bonding force between the fibers may be lowered, and thus shape stability may be deteriorated. Therefore, it is necessary to use a carbon fiber of an appropriate length, and the average fiber length may vary depending on the type of carbon fiber to be used and the fiber diameter.

In addition, if the fiber diameter of the carbon fiber is too large, the size of the pores may be too large, and if the fiber diameter is too small, the processability may be poor and bonding may be difficult, so a carbon fiber having an appropriate average fiber diameter may be used. For example, the fiber length of carbon fiber may be 2 to 12 mm, and the fiber diameter may be 1 to 100 μm.

In addition, the content of the binder may be dispersed in the solution to include an average of 0.001 to 0.03 wt% based on the total weight of the dispersion solution. Specifically, the binder may be dispersed to contain an average of 0.001 to 0.03% by weight and an average of 0.01% by weight based on the total weight of the dispersion solution.

The binder is an additive for imparting functionality such as bonding and adhesion between fibers when the carbon fibers form a carbon fiber web. When the content of the binder is less than 0.001% by weight based on the total weight of the dispersion solution, the bond and adhesion between the carbon fibers may be lowered, and thus the shape stability of the carbon fiber paper produced may be deteriorated. In addition, with respect to the total weight of the dispersion solution, when it exceeds 0.03% by weight, aggregation between carbon fibers may occur. Therefore, it may be preferable to include the binder in the above-mentioned range.

The binder may be at least one selected from the group consisting of cellulose, polyvinyl alcohol (PVA), cellulose nanofibers (CNF), and cellulose nanocrystals (CNC).

and mixing the dispersion solution in which the carbon fibers are dispersed and the dispersion solution in which the binder is dispersed with each other. The above step may be processed by a conventional stirrer, and various stirrers such as a blade mixer, a ribbon mixer, and a screw mixer may be used.

And, vacuum filtering the dispersion solution in which the carbon fibers and the binder are dispersed to filter the carbon fibers to form a carbon fiber web (S200).

Specifically, a conventional vacuum filter device may be used, and the carbon fiber may be filtered by slowly pouring the mixed solution by stirring the device.

After filtering of the carbon fibers, the carbon fibers may be bonded to each other by the dispersant and binder remaining after filtering. At this time, since the carbon fibers themselves are connected to each other and are combined by the dispersant and the binder, the tensile strength of the carbon fiber web can be increased. The carbon fiber web may mean a carbon fiber nonwoven fabric.

Next, it includes a step (S300) of drying the carbon fiber web. Specifically, since the carbon fiber web is formed through stirring of an aqueous solution, vacuum filtration, etc., the remaining carbon fiber web is dried. It may be naturally dried, but the carbon fiber remaining in moisture for a predetermined time at a predetermined temperature may be dried by heating using a device such as a dryer or drying using hot air. For example, the carbon fiber nonwoven fabric can be dried by placing it in a space of about 120 degrees Celsius for about 30 minutes.

In addition, there is provided a carbon fiber paper produced by the method for producing the above-described carbon fiber paper according to an embodiment of the present invention.

When the carbon fiber paper according to an embodiment of the present invention implements a planar heating element, the higher the tensile strength and thermal conductivity, the more advantageous, and the lower the sheet resistance. In particular, the carbon fiber paper according to an embodiment of the present invention may have a sheet resistance of 4 Ω/m ² or less, or 3 Ω/m ² or less, for example, the sheet resistance of the carbon fiber paper is 2 to Ω/m ² or less.

In addition, the carbon fiber paper according to an embodiment of the present invention may have a tensile strength of 2 MPa or more, or 6 MPa or more. For example, when the dispersant contains 0.8 wt %, the tensile strength of the carbon fiber paper may be an average of 12 MPa. Furthermore, the carbon fiber paper may have an average thermal conductivity of 1 W/mk or more. Specifically, the average thermal conductivity of the carbon fiber paper may be in the range of 1 to 3 W/mk.

In addition, when the carbon fiber paper implements a planar heating element, the surface heating temperature may be 80 ℃ or more, or may be in the range of 100 to 120 ℃.

Figure 2 is a schematic diagram of a carbon fiber planar heating element comprising a carbon fiber paper according to an embodiment of the present invention.

2, the carbon fiber planar heating element 100 including the carbon fiber paper according to an embodiment of the present invention is the carbon fiber paper 110, a pair of metals located on two parallel sides of the carbon fiber paper electrode 120; and an insulating sheet 130 attached to at least one surface of the carbon fiber; It provides a carbon fiber planar heating element 100 comprising a.

"Plane heating element" means an object that generates heat in a plane state. After installing metal electrodes on both ends of a thin conductive heating element, insulate it with an insulating material and apply the rated voltage to the metal electrode, so that the entire surface It means to generate heat in As the electrode material of the planar heating element, silver (Ag), copper (Cu), etc. are used, and as the material of the heating element composed of carbon, carbon paste, carbon fiber, etc. are used.

Specifically, in the carbon fiber planar heating element 100 according to an embodiment of the present invention, the carbon fiber paper 110 serves as a heating part, and the above-described dispersant and binder may bind the carbon fibers to each other. The carbon fiber paper 110 has a low sheet resistance, and the thickness of the carbon fiber paper 110 is thin, so that the tensile strength per unit area is increased, so that it is not easily torn. For example, the carbon fiber paper 110 may have a cross-sectional size of 50 mm×50 mm or more, and a thickness of 300 μm or less.

The metal electrode 120 may be attached to both sides of either the upper surface or the lower surface of the carbon fiber paper 110 . The metal electrode 120 may be made of a metal including copper, aluminum, silver, nickel, tin, or an alloy thereof, and the shape of the metal electrode 120 may be a ribbon or a linear shape. For example, a wire-shaped copper wire or a silver-plated copper wire may be used as the metal electrode 120 . Specifically, as the metal electrode 120 , a copper ribbon having a width of 5 to 10 mm and a thickness of 3 to 100 μm may be used.

Here, the carbon fiber paper 110 becomes a heating element that radiates heat, and the metal electrode 120 transmits a current 110 to the carbon fiber paper that radiates heat. That is, the carbon fiber paper 110 becomes a heating part, and the metal electrode 120 becomes an electrode part.

The insulating sheet 130 is laminated on at least one surface of the carbon fiber paper 110, and forms an insulating layer. Preferably, it can be laminated on both sides of the carbon fiber paper 110 in order to prevent damage to the carbon fiber paper 110 and prevent current flow, and can be configured in a double layer to prevent the risk of penetration of moisture, etc. have. The insulating sheet 130 may be formed of a non-conductive film or cloth. The non-conductive film may be in the form of a non-woven or woven fabric or in the form of a film. As the fabric type, a mesh-type cloth, non-woven fabric, sponge-type, etc. may be used. The insulating sheet 130 may be manufactured to have the same size and thickness and may be attached to both sides of the carbon fiber paper 110, but the two insulating sheets 130 may have different thicknesses in order to concentrate the heat dissipation in one direction. . For example, in the direction where heat dissipation is not required and heat retention is required, heat dissipation is prevented by arranging an insulating sheet 130 of about 1 mm, and an insulating sheet of 10 to 500 μm is disposed on the opposite side where heat dissipation is required to facilitate heat transfer. can do.

The carbon fiber planar heating element 100 described above has a low sheet resistance and high electrical conductivity, so it is possible to drive a low voltage of about 5V, thereby lowering the risk of overheating and fire, and can be manufactured as a portable type using a portable lithium ion battery This can greatly increase convenience. By using this carbon fiber planar heating element 100, it is thin, and at low cost, it is possible to produce a high-conductivity, high-heating heating cushion, a heating blanket, a heating mat, a heating sheet for a vehicle, a cotton heating element for construction, etc.

Hereinafter, the present invention will be described in more detail by way of Examples and Experimental Examples.

However, the following Examples and Experimental Examples are merely illustrative of the present invention, and the content of the present invention is not limited to the following Examples and Experimental Examples.

<Example>

Examples 1-5. Manufacture of carbon fiber paper

Carboxylmethyl cellulose (CMC) was added to distilled water, and 0.03 wt% of carbon fiber h 6mm and 0.01 wt% of polyvinyl alcohol (PVA) were dispersed in the solution. Then, the mixture was stirred with a stirrer. Then, the solution was filtered by slowly pouring an aqueous solution dispersed by stirring into a vacuum filter device to prepare a carbon fiber web, and the carbon fiber web was dried by placing it at a temperature of 120° C. for 30 minutes.

The input amount of carboxylmethyl cellulose according to Examples is summarized in Table 1 below.

Example Dispersant content (wt%) Example 1 0.2 Example 2 0.4 Example 3 0.6 Example 4 0.8 Example 5 1.0

<Comparative example>

Comparative Example 1.

Carbon fiber paper was prepared in the same manner as in Example 1, except that carboxylmethyl cellulose was not added to distilled water.

<Experimental example>

Experimental Example 1. Physical properties of carbon fiber paper according to the content of dispersant

3 is a photograph showing dispersion images of carbon fibers according to various concentrations in Examples 1 to 5 of the present invention.

Referring to FIG. 3 , as the concentration of the dispersant increases, the bonding force between the carbon fibers increases, thereby confirming the aggregation of the carbon fibers.

Experimental Example 2. Measurement of tensile strength according to the content of dispersant

The tensile strengths of the carbon fiber papers prepared in Examples 1 to 5 and Comparative Examples were measured.

And, the result is shown in FIG. 4 is a graph showing the tensile strength of the carbon fiber paper prepared in Examples 1-5 and Comparative Examples.

Referring to FIG. 4 , it can be seen that the tensile strength of the carbon fiber paper produced according to the content of the dispersant is confirmed, and in the case of the comparative example that does not contain the dispersant, it can be confirmed that the tensile strength is very low. And, the tensile strength of Example 4 containing 0.8% by weight of carboxymethyl cellulose was the highest.

Experimental Example 3. Measurement of sheet resistance according to the content of the dispersant

A planar heating element was prepared using the carbon fiber paper prepared in Examples 1 to 5 and Comparative Examples. Specifically, a pair of copper electrodes were installed on two parallel sides of the carbon fiber paper prepared in Examples 1 to 5 and Comparative Example, and insulating sheets were attached to both sides of the carbon fiber paper.

Then, the sheet resistance of the prepared planar heating element was measured, and the result is shown in FIG. 5 . 5 is a graph showing the sheet resistance of the planar heating element comprising the carbon fiber paper prepared in Examples 1-5 and Comparative Examples.

Referring to FIG. 5 , it can be seen that the sheet resistance result of the planar heating element manufactured according to the content of the dispersant is confirmed, and it can be seen that the interfacial contact resistance of the comparative example is higher than that of the example.

Experimental Example 4. Measurement of thermal conductivity according to the content of dispersant

Thermal conductivity was measured using a planar heating element under the same conditions as in Experimental Example 3.

And, the result is shown in FIG. 6 is a graph showing the thermal conductivity of the planar heating element comprising the carbon fiber paper prepared in Examples 1-5 and Comparative Examples.

Referring to FIG. 6 , it can be seen that the thermal conductivity of the planar heating element including the carbon fiber paper prepared according to the content of the dispersant is confirmed, and in the case of the comparative example that does not contain the dispersant, it can be confirmed that the thermal conductivity is very low.

Experimental Example 5. Measurement of surface heating temperature according to the content of dispersant

The surface heating temperature was measured using a planar heating element under the same conditions as in Experimental Example 3.

And, the result is shown in FIG. 7 is a graph showing the surface heating temperature of the planar heating element comprising the carbon fiber paper prepared in Examples 1-5 and Comparative Examples.

Referring to FIG. 7, it can be confirmed that the surface heating temperature of the planar heating element including the carbon fiber paper prepared according to the content of the dispersant is confirmed, and in the case of the comparative example that does not contain the dispersant, it can be confirmed that the surface heating temperature is very low.

Claims (8)

In the manufacturing method of carbon fiber paper for planar heating element,
dispersing carbon fibers in a dispersion solution;
dispersing a binder in the dispersion solution; and
Dispersing and mixing carbon fibers and a binder in a dispersion solution containing a dispersant comprising the step of mixing a dispersion solution in which carbon fibers are dispersed and a dispersion solution in which a binder is dispersed;
forming a carbon fiber web by vacuum filtering the dispersion solution in which carbon fibers and binders are dispersed to filter the carbon fibers; and
Drying the carbon fiber web; includes,
The content of the carbon fiber is 0.01 to 0.05% by weight based on the total weight of the dispersion solution,
The content of the binder is 0.001 to 0.03 wt% based on the total weight of the dispersion solution,
The content of the dispersant is 0.8% by weight based on the total weight of the dispersion solution,
The carbon fiber paper has a sheet resistance of 4 Ω/m ² or less, a tensile strength of 12 MPa and a thermal conductivity of 1 to 3 W/mK.
delete delete delete The method of claim 1,
Dispersants include guar gum, arabic gum, Xtanthan gum, methyl cellulose (MC), carboxymethyl cellulose (CMC) and hydroxyethyl cellulose (Hydroxyethyl). Cellulolse, HEC))) Method for producing carbon fiber paper for a planar heating element, characterized in that at least one selected from the group consisting of.
The method of claim 1,
Binder, cellulose (cellulose), polyvinyl alcohol (PVA), cellulose nanofiber (CNF) and cellulose nanocrystal (Cellulose nanocrystal, CNC) of carbon fiber paper for planar heating element, characterized in that at least one selected from the group consisting of manufacturing method.
A carbon fiber paper produced by the method for producing a carbon fiber paper according to any one of claims 1, 5 and 6;
a pair of metal electrodes positioned on two parallel sides of the carbon fiber paper; and
an insulating sheet attached to at least one surface of the carbon fiber; Including, a sheet resistance of 4 Ω / m ² Carbon fiber planar heating element, characterized in that less than.
8. The method of claim 7,
The carbon fiber planar heating element thermal conductivity is 1 W / mk or more of the carbon fiber planar heating element.

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