WO2015076390A1

WO2015076390A1 - Carbon heating composition and carbon heating element

Info

Publication number: WO2015076390A1
Application number: PCT/JP2014/080971
Authority: WO
Inventors: 光彦飯野; 和彦武藤; 正田　浩一; 剛文佐藤; 仁田渕
Original assignee: 東洋ドライルーブ株式会社
Priority date: 2013-11-22
Filing date: 2014-11-21
Publication date: 2015-05-28
Also published as: JPWO2015076390A1; CN105637977A; JP5866073B2

Abstract

Provided are a carbon heating composition and a carbon heating element which exhibit excellent heating efficiency. This carbon heating composition contains a prescribed amount, in relation to a binder, of graphite and carbon nanotubes as carbon components in a prescribed blending ratio; hence, the graphite and the carbon nanotubes are dispersed in the binder in a well-balanced manner. In addition, a carbon heating element obtained by producing a film from said composition is usable, when shaped into a planar carbon heating element (1) or the like forming a film (2) on a prescribed sheet and exhibiting excellent heating efficiency, as a heat-radiating member in a heating device, temperature control device, snow-melting device, or the like, a component or the like of a vehicle, motorcycle, or the like, and as a component or the like to be mounted onto various types of vehicles including wheeled machines, general machinery and equipment such as endless-track-equipped machines, transportation equipment, transportation vehicles, mechanical vehicles, and the like.

Description

Carbon exothermic composition and carbon exothermic body

The present invention relates to a carbon exothermic composition and a carbon exothermic body. More specifically, the present invention relates to a carbon exothermic composition and a carbon exothermic body having excellent exothermic efficiency.

As a conventional heating element, for example, a configuration in which a nichrome wire is attached to a predetermined insulating base material, and this is covered with an electric insulating plate or the like and sandwiched is employed. On the other hand, the planar heating element having such a configuration is a local heating type that generates heat in the nichrome wire portion, and only the nichrome wire arranged in a meandering manner and the periphery thereof are heated, while the portions other than the nichrome wire are in heat conduction. However, the entire heating element is difficult to generate heat, and the heat efficiency is poor. In addition, since the nichrome wire itself must be heated to generate heat over the entire sheet-shaped heating element, it may cause burns depending on the material of the electrical insulating plate, and in some cases there is a risk of fire. There was a problem.

In order to solve such a problem, it is considered to use a carbon component having high resistance. For example, as a heating element, a carbon heating composition in which a powdery carbon component is mixed and dispersed with a binder made of a predetermined resin material to form a paint, ink, etc., and such a composition is applied to a predetermined substrate, coated, A carbon heating element with a film formed by printing, baking, etc. has good heat generation efficiency, such as being able to generate heat uniformly over the entire surface, and is excellent in adaptability to the shape of the substrate, and is highly adaptable to mass production. It is done. Such carbon heating elements are used, for example, as heating media such as heaters in a wide range of applications, and those having PTC characteristics by using a crystalline resin as a base polymer are also being studied. (For example, see Patent Document 1 and Patent Document 2.)

JP 2000-82571 A JP 2010-45025 A

On the other hand, with the carbon heating elements currently provided, depending on the type of carbon component, etc., the heat generation efficiency as expected may not be exhibited, and improvement has been demanded.

The present invention has been made in view of the above problems, and an object thereof is to provide a carbon exothermic composition and a carbon exothermic body having excellent exothermic efficiency.

In order to solve the above problems, a carbon exothermic composition according to the present invention is a carbon exothermic composition in which a powdery carbon component is dispersed in a binder, and the carbon component includes graphite and carbon nanotubes, The compounding ratio of the graphite and the carbon nanotube is graphite / carbon nanotube = 2.5 to 5.4, and the graphite and the carbon nanotube are contained in a total of 50 to 300 parts by mass with respect to 100 parts by mass of the binder. It is characterized by doing.

The carbon exothermic composition according to the present invention is characterized by further containing powdered silicon carbide in the above-described present invention.

The carbon exothermic composition according to the present invention is characterized in that, in the above-described present invention, the binder is at least one selected from a polyurethane resin, a polyamideimide resin and a fluororubber.

The carbon heating element according to the present invention is a film made of the above-described carbon heating composition according to the present invention.

The carbon heating element according to the present invention is characterized in that, in the above-described present invention, the coating is formed on a predetermined base material.

The carbon heating element according to the present invention is a planar heating element in which the coating film is formed on the planar substrate in the above-described present invention.

Since the carbon exothermic composition according to the present invention contains graphite and carbon nanotubes having a predetermined mixing ratio as carbon components in a predetermined content with respect to the binder, the graphite and carbon nanotubes are balanced in the binder. A carbon heating element that is well dispersed and formed with such a composition has excellent heat generation efficiency, for example, a heating member in a heating device, a temperature control device, a snow melting device, etc., a part of an automobile, a motorcycle, etc., an agricultural machine, It can be widely used for parts attached to various types of vehicles such as cranes, excavators and other machines with wheels, and general machinery and equipment including caterpillar-equipped machines, transportation equipment, transportation vehicles, and mechanical vehicles.

4 is a schematic diagram illustrating a configuration of a test sample in Test Example 1. FIG. FIG. 2 is a cross-sectional view taken along the line AA in FIG. In Experiment 5, it is the figure which showed the relationship between application time and raise temperature. In Experiment 8, it is the figure which showed the relationship between application time and raise temperature.

Hereinafter, the structure of the carbon exothermic composition and the carbon exothermic body according to the present invention will be described. The carbon exothermic composition of the present invention is a carbon exothermic composition in which a powdery carbon component is dispersed in a binder, and the carbon component contains carbon nanotubes and graphite. In addition, in this invention, about content of a component, component ratio (blending ratio), etc., it is a value about solid content about a binder, and the blending ratio of a graphite and a carbon nanotube (CNT) is a mass ratio. is there.

(A) Carbon component:
The carbon exothermic composition of the present invention contains graphite and carbon nanotubes as a powdery (particulate) carbon component.

In the present invention, graphite and carbon nanotubes are used in combination as described above. However, when only graphite is used alone, the graphite generally has a relatively large particle shape. Although it is possible to significantly reduce the resistance value of the (carbon heating element), the effect on the heat generation action is often not obtained. On the other hand, when only carbon nanotubes are used alone, it may be difficult to obtain a sufficient connection between the carbon nanotubes in the coating composed of the carbon exothermic composition. It may be necessary to add nanotubes. In the present invention, by using graphite and carbon nanotubes in combination, the carbon nanotubes are connected to each other via graphite or a binder while reducing the overall resistance value, and in particular, a parallel circuit is formed. Thus, the generation of heat is promoted, and the heat generation efficiency is improved.

Graphite (graphite) is generally an elemental mineral composed of carbon, and is a layered structure in which a plurality of carbon hexagonal network surfaces (surfaces in which a plurality of six carbon rings are connected to form one layer) are laminated in layers. In the present invention, it includes artificial graphite, graphite-coated diamond, soil graphite, and the like.

Graphite is used in the form of powder. Specific examples of the shape of the graphite include, for example, a spherical shape, a granular shape, and a flake shape such as a scale shape or a scale shape, but are not particularly limited thereto. . In addition, common shapes may be used alone, or different shapes may be used in combination. In the present invention, it is preferable to use flake-like graphite having a scaly shape, a scaly shape, or the like. By using these shapes, heat generation efficiency can be improved.

Note that the heat generation efficiency can also be improved by using artificial graphite as the graphite.

As for the size of powdered graphite, the average particle size (average primary particle size) should be about 0.1 to 30 μm for graphite particles that are relatively uniform in shape, such as spherical shapes. Is preferred. By setting the average particle diameter in such a range, the dispersibility is good with respect to the binder, and heat generation can be performed efficiently. The average particle diameter of graphite is particularly preferably about 1 to 15 μm. The average particle diameter of the powdered graphite is, for example, a conventionally known means such as an average value obtained by observing graphite with a scanning electron microscope and measuring the particle diameter of any 50 (or 100) graphite particles. What was measured can be adopted.

The average particle diameter (average primary particle diameter) when the graphite is in the shape of flakes such as scales or scales is preferably about 0.1 to 30 μm. By setting the average particle diameter in such a range, the dispersibility is good with respect to the binder, and heat generation can be performed efficiently. The average particle diameter of the flaky graphite is particularly preferably about 1 to 15 μm. The average particle diameter of the flaky graphite is, for example, an average value (average major axis) obtained by observing the flaky graphite with a scanning electron microscope and measuring the major axis of arbitrary 50 (or 100). Find it from

Carbon nanotubes (Carbon Nanotubes: CNTs) are generally fiber particles made of a polymer in which hexagonal lattices of carbon atoms are arranged in a cage-like sheet, and form a long hollow micro hollow cylinder. Yes. In general, a carbon nanotube has a graphite structure in which carbon atoms are arranged in a hexagon, and a sheet made of carbon is wound into a cylindrical shape and is called a single-walled carbon nanotube. A tube composed of several sheets (for example, about 2 to 5 sheets) is called a multi-walled carbon nanotube.

In the present invention, the average length (fiber length) of the powdered carbon nanotube is preferably about 0.1 to 50 μm, and the average outer diameter (fiber diameter) of the carbon nanotube is about 10 to The thickness is preferably 1000 nm. By setting the average length and the average outer diameter of the carbon nanotube within such a range, it becomes possible to efficiently exhibit the characteristics of the carbon nanotube and improve the heat generation efficiency. The average length of the carbon nanotube (fiber length) Is particularly preferably about 1 to 20 μm, and the average outer diameter (fiber diameter) is particularly preferably about 50 to 300 nm. The average length and average outer diameter of the carbon nanotubes in the present invention are, for example, the results of measuring the length and outer diameter of any 50 (or 100) carbon nanotubes observed with a scanning electron microscope. What is necessary is just to obtain | require from an average value etc.

The carbon nanotube may be, for example, a commercially available long carbon nanotube treated at a low temperature by a mechanical treatment such as ball milling so as to be within the above average length (fiber length).

Moreover, it is preferable to use carbon nanotubes that have been previously subjected to a dispersion treatment. By performing the dispersion treatment, it is possible to greatly improve the heat generation effect when the film is formed. The dispersion treatment is not particularly limited, and a conventionally known dispersion treatment or the like can be used. For example, after mixing a carbon nanotube into a system in which a wet additive is added to a predetermined solvent to obtain a mixed system, You may make it use the bead media dispersion | distribution etc. which are carried out by throwing beads, such as a titania bead, in such a mixing system and stirring. As a component of the wetting and dispersing agent, generally, a polymer copolymer, a block copolymer, an unsaturated polycarboxylic acid polymer, an acrylic copolymer, a phosphate ester copolymer, an alkyl ammonium salt, or the like is used. be able to. As the solvent, for example, MEK (methyl ethyl ketone), IPA (isopropyl alcohol), NMP (n-methylpyrrolidone), butyl acetate, anone (cyclohexanone) and the like can be used.

The compounding ratio of graphite and carbon nanotube (CNT) in the carbon component is in the range of graphite / carbon nanotube = 2.5 to 5.4. By making the blend ratio within this range, the balance between graphite and carbon nanotubes is good, and because the electrical properties of carbon nanotubes are specifically expressed on the entire surface of the film such as a sheet, heat generation efficiency is excellent. Can be. The blending ratio is more preferably in the range of graphite / carbon nanotubes = 2.7 to 4.5, particularly preferably in the range of 2.8 to 3.7.

In the carbon exothermic composition according to the present invention, the total content of graphite and carbon nanotubes as the carbon component is 50 to 300 parts by mass with respect to 100 parts by mass of the binder. If the total content of graphite and carbon nanotubes is less than 50 parts by mass, the exothermic properties may not be exhibited, or a high voltage may be required to exhibit them, while if the content is more than 300 parts by mass, it is obtained. In some cases, the resulting carbon heating element coating loses its smoothness. The total content of graphite and carbon nanotubes is preferably 80 to 200 parts by mass, and particularly preferably 90 to 180 parts by mass with respect to 100 parts by mass of the binder.

In order to maintain the above content, the graphite as the carbon component is preferably 10 to 200 parts by weight, more preferably 50 to 170 parts by weight, and more preferably 70 to 70 parts by weight with respect to 100 parts by weight of the binder. It is especially preferable to set it as 145 mass parts. Similarly, the carbon nanotube is preferably 1 to 100 parts by mass, more preferably 5 to 80 parts by mass, and particularly preferably 15 to 45 parts by mass with respect to 100 parts by mass of the binder.

(B) Binder (binder component):
The binder constituting the carbon exothermic composition according to the present invention serves as a medium in which the above-described carbon component is dispersed (for example, a state where the carbon component is uniformly dispersed in the binder as much as possible). The binder is not particularly limited, and known resins such as solvent-based resins and water-based resins can be used, but it is preferable to use solvent-based resins, for example, polyurethane-based resins, polyolefin-based resins such as polypropylene, Halogenated resins such as polyvinyl chloride or polyvinylidene chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymers, vinyl resins such as ethylene-vinyl acetate copolymers or polyacrylates, polyethylene terephthalate or polybutylene Polyester resins such as terephthalate, polystyrene resins, polyamide resins, polyimide resins, polyether ether ketone resins, nitrocellulose resins, polyether imide resins, polyamide imide resins, fluoro rubber, silicone rubber A seed elastomer (rubber) resin or the like can be used, and a resin obtained by dispersing or emulsifying these may be used. These solvent-based resins may be used alone or in combination of two or more. In addition, the binder may be cross-linked by adding a cross-linking agent to a binder such as various elastomer (rubber) resins including fluororubber or the like or other resins, or by performing electron beam cross-linking.

In the present invention, it is preferable to use polyurethane resin, polyamideimide resin, or fluororubber as the binder. By using a polyurethane-based resin, a polyamide-imide resin, or a fluororubber as a binder, the heat generation efficiency of a carbon exothermic composition or a film made of such a composition can be improved, and in particular, by using a polyurethane-based resin, A carbon heating element provided with a film with excellent flexibility is provided, and since the affinity with the carbon material is good, the heating efficiency can be improved even in various shapes. Further, by using a polyamideimide resin, it is possible to provide a carbon heating element provided with a film having excellent heat resistance in addition to improvement in heat generation efficiency. Furthermore, by using fluororubber, in addition to improving the heat generation efficiency, it is possible to reduce the weight of the carbon heating element and to impart flexibility to the carbon heating element. One type of polyurethane-based resin, polyamideimide-based resin, or fluororubber may be used alone, or two or more types may be used in combination.

In addition, when the binder is a solvent-based resin, the organic solvent to be used can be used without particular limitation as long as it can dissolve or disperse the thermoplastic resin. For example, hydrocarbon solvents such as hexane and pentane, aromatic solvents such as xylene, toluene, benzene and ethylbenzene, ketone solvents such as MEK (methyl ethyl ketone) and acetone, butanol, propanol, ethanol, methanol, isopropyl alcohol (IPA), alcohol solvents such as phenol, DMF (dimethylformamide), NMP (n-methylpyrrolidone), DMAC (dimethylacetamide), anone (cyclohexanone), butyl acetate, etc. can be used, and these solvents May be used alone or in combination of two or more.

Solvents include, for example, MEK (methyl ethyl ketone), butyl acetate, n-butanol, and IPA (isopropyl alcohol) for polyurethane resins, and DMF (dimethylformamide), NMP (n-methyl) for polyamideimide resins. Pyrrolidone), MEK, IPA, DMAC (dimethylacetamide), etc., polyacrylic resin, polyvinyl resin, toluene, n-butanol, MEK, silicon acrylic resin, xylene, ethylbenzene, n-butanol, IPA , MEK, etc., epoxy resin, phenolic resin, xylene, ethylbenzene, MEK, n-butanol, phenol, etc., and fluorine rubber, one kind of solvent such as anone (cyclohexanone), butyl acetate, etc. Anyway It can be used in combination of two or more.

In addition, it is preferable to add powdered silicon carbide (SiC) to the carbon exothermic composition according to the present invention in order to improve the heat generation efficiency. The average particle diameter (average primary particle diameter) of silicon carbide is preferably about 0.03 to 10 μm.

The silicon carbide is preferably 5 to 80 parts by mass with respect to 100 parts by mass of the binder. By containing silicon carbide in such a range with respect to the binder, in addition to the effect of the carbon component, the heat generation efficiency can be improved efficiently. The amount of silicon carbide is particularly preferably 10 to 50 parts by mass with respect to 100 parts by mass of the binder.

It should be noted that various components and additives other than those described above can be appropriately added to the carbon exothermic composition according to the present invention as necessary within the range not hindering the object and effect of the present invention.

For example, as a conductive material, graphene, carbon black, carbon fiber (carbon fiber), acetylene black, and other general powder carbon materials other than the above-described carbon components, conductive ceramic fibers, conductive whiskers, metal fibers , Conductive inorganic oxides, conductive polymer fibers, metal powders such as alumina, and the like.

In the binder, conventionally known additives such as ultraviolet absorbers, heat stabilizers, antioxidants, or various additives such as surface modifiers and viscosity modifiers for improving processability are appropriately used. Can be added.

The carbon exothermic composition according to the present invention mixes the above-described carbon component, essential components such as a binder such as a solvent-based resin dissolved in a solvent, silicon carbide added if necessary, and an additive, and the powder is mixed in the binder. It can be easily produced by dispersing the carbon component and the like.

The carbon exothermic composition thus obtained becomes a material having excellent exothermic efficiency, and a carbon heating element comprising a film formed by directly forming such a carbon exothermic composition, or a film made of the carbon exothermic composition Can be used as a carbon heating element formed on a predetermined substrate.

In the case of using a base material, the shape of the base material is not particularly limited, and can be appropriately determined according to the required product shape in addition to a sheet shape (planar shape). The material for forming the base material is not particularly limited, but in the case of a planar shape, a sheet (film) made of a plastic material having good electrical insulation properties such as polycarbonate, polyester, polyamide, polyphenol, polyetherimide, etc. In the case of a predetermined shape such as a three-dimensional shape that is not planar, materials other than the plastic material described above can be used as appropriate. For example, when using a base material made of a conventionally known metal-based material, it is preferably used after the primer treatment. If it is a product using cloth, leather, fiber, non-woven fabric, etc., the cloth, leather, fiber, non-woven fabric, etc. can be used as they are or after being appropriately processed as necessary.

In addition, in order to heat a carbon heating element, there is no restriction | limiting in particular, Although conventionally well-known operation can be used, For example, although illustrated also in FIG.1 and FIG.2 mentioned later as a test sample, a carbon heating composition Heat can be easily generated by an operation such as disposing an electrode or the like on the coating film and applying a predetermined voltage. Here, the magnitude of the voltage, the application time, the type of the electrode, etc. are not particularly limited, and can be appropriately determined according to the required specifications, etc. For example, the electrode is formed by using a highly conductive material. It can be easily formed by disposing on the surface or inside of the coating, or coating the coating surface.

The carbon heating element according to the present invention can be used as a planar heating element formed on a planar substrate such as a sheet (including a film). The carbon heating element as such a planar heating element is extremely excellent in heat generation efficiency, such as being able to generate heat uniformly over the entire surface, and being shaped to adhere to the substrate stably, etc. It is excellent in adaptability to. The coating by the carbon exothermic composition part may be formed on one side of the substrate or on both sides according to the required specifications.

In forming the carbon exothermic composition film on the surface of the substrate, as a pretreatment for the substrate, washing with an organic solvent such as IPA (isopropyl alcohol) and acetone, detergent (surfactant), acid, alkali, etc. Means such as shot blasting or chemical etching with alumina powder or the like may be used depending on the material forming the base material or the shape of the base material. For example, when a plastic material or the like is used as the base material, it is preferable to perform cleaning with IPA or the like as the pretreatment.

As a method of applying the carbon exothermic composition to the base material by applying the carbon exothermic composition to the base material, the so-called spray coating, brush coating, roller coating, screen printing, pad printing, gravure printing, An immersion method (dipping) or the like can be used.

In addition, you may make it heat-process for the formation of a film if needed. The conditions for the heat treatment are not particularly limited and can be appropriately determined depending on the heat-resistant temperature of the base material, the type of binder and solvent used, etc., but is generally from room temperature to 300 ° C. for about 1 minute to 1 hour. Is preferred. In addition, since formation of a film (film formation) should just be able to volatilize and harden the solvent of a carbon exothermic composition when using solvent system resin, depending on the kind of a binder and a solvent, etc., it is carbon exothermic composition. After applying an object to a predetermined thickness, the solvent may be volatilized by leaving it at room temperature.

When the carbon heating element is used as a film formed by directly forming the carbon heating composition, for example, the carbon heating composition is applied to a predetermined peelable substrate, substrate, etc. A film may be formed by a method similar to the method for forming a film on a substrate, and the film may be peeled off from a substrate or the like to be used as a carbon heating element.

The thickness of the carbon heating element coating is not particularly limited, and may be appropriately determined according to the application to be used and the required heating characteristics, weather resistance, durability, etc. When a sheet-like carbon heating element formed on a sheet-like (planar) base material is used to maintain the strength while exhibiting the strength, it is preferably about 5 to 1000 μm, and preferably about 20 to 200 μm. Particularly preferred. On the other hand, when a carbon heating element is formed on a substrate having a predetermined shape that is not planar, it is preferably about 5 to 1000 μm, and more preferably 20 to 200 μm. Further, when the carbon heating composition is used as a film formed by directly forming a carbon heating composition, the thickness is preferably 5 to 1000 μm, and more preferably 20 to 500 μm. In addition, the thickness of the planar substrate in the case where the substrate is a sheet or the like and is a planar carbon heating element is not particularly limited, and may be appropriately determined according to the required specifications and applications. That's fine.

Such a carbon heating element according to the present invention includes graphite and carbon nanotubes having a predetermined mixing ratio as carbon components in the carbon heating composition that is a component of the coating film, with a predetermined content with respect to the binder. Therefore, graphite and carbon nanotubes are dispersed in a well-balanced manner in the binder, resulting in excellent heat generation efficiency. Such carbon heating elements are used in various fields that require a heating effect, such as heating devices (floor heating, non-combustion heating devices such as carpets), temperature control devices (heaters, preheating devices, etc.), Heat-generating members in snow-melting devices, parts for automobiles, motorcycles, etc. (for example, seat heaters, preheating devices, interior panel heaters, etc.), machines with wheels, such as agricultural machines, cranes, excavators, etc. Can be used widely in fields and applications where conventional heating elements have been applied, such as general equipment including machinery, transportation equipment, transportation vehicles, mechanical vehicles, etc. Can do.

Hereinafter, the present invention will be described in more detail based on examples and comparative examples, but the present invention is not limited thereto.

[Production Example 1]
Production of carbon exothermic composition (1):
Graphite, carbon nanotubes (dispersed), which are powdery carbon components (hereinafter sometimes simply referred to as “carbon components”), and the following materials as binders dissolved in a solvent have the compositions shown in Table 1. It was set as the carbon exothermic composition of Example 1 thru | or Example 11 and Comparative Example 1 thru | or Comparative Example 6 which disperse | distributed the carbon component in the binder mix | blended and mixed and dissolved in the solvent. In addition, about the carbon nanotube, what was disperse-processed with the following method was used. In Table 1 and Tables 2 to 6 to be described later, the numerical values of the binder and the carbon component (Table 4 also includes silicon carbide) are the content (the solid content of the binder), and the carbon component content. Is 100 parts by mass with respect to 100 parts by mass of the binder. The binder is 100 parts by mass in total for Table 2, 100 parts by mass of the polyurethane-based resin serving as the binder for Tables 1, 3 and 4, and Table 5 The fluororubber serving as the binder is 100 parts by mass, and in Table 6, the polyamideimide resin serving as the binder is 100 parts by mass.

(Method of dispersion treatment of carbon nanotube)
Carbon nanotubes are mixed into a solvent (mixed system of methyl ethyl ketone and isopropyl alcohol) and a wetting additive (alkyl ammonium salt of a polymer copolymer) is added, and titania beads with an outer diameter of φ1.4 mm are added to this. The mixture was stirred and dispersed by bead media dispersion. After the dispersion treatment, the titania beads were removed and used as a dispersion-treated carbon nanotube (the carbon nanotube dispersion treatment is the same for the following production examples).

(Carbon component)
(1) Graphite-1 (G-1) (flaky graphite, average particle size: 10 μm)
(2) Graphite-2 (G-2) (scale graphite, average particle size: 1 μm)
(3) Carbon nanotube (CNT) (average length (fiber length) 6 μm, average outer diameter (fiber diameter) 100 nm, multilayer)

(Binder (solvent resin))
(1) Polyurethane resin (UR) (polyurethane resin dissolved in a solvent (mixed solvent of MEK (methyl ethyl ketone), butyl acetate, n-butanol, IPA (isopropyl alcohol)))

[Production Example 2]
Production of carbon heating element (1):
As shown in FIG. 1 and FIG. 2 (both will be described later), the carbon exothermic composition obtained in Production Example 1 is a base material (polycarbonate sheet, size: width) provided with electrodes made of aluminum tape on both sides of the long side. After spray coating (spray coating) on one side (surface on which electrodes are arranged) of 3 mm (50 mm × length 100 mm × 2 mm) 3, 80 ° C. × 60 minutes using a high-temperature incubator (Temperature Equipment Laboratory) The sheet-like carbon heating element 1 (test sample 1) in which the electrode 4 and the coating 2 of the carbon heating composition were formed on one side of the substrate 3 was formed by baking and drying. The thickness of the coating 2 of the carbon exothermic composition was set to 40 to 50 μm (the thickness of the coating 2 was about Production Example 4, Production Example 6, Production Example 8, Production Example 11 and Production Example 13). The same is true.)

FIG. 1 is a schematic diagram showing a configuration of a test sample 1 in Test Example 1 described later, and FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1 (note that FIG. (The unit of numerical values indicating the width, length, etc. in FIGS. 1 and 2 is mm.) As shown in FIG. 1 and FIG. 2, an aluminum sheet having a width of 5 mm, a length of 100 mm, and a thickness of 130 μm is arranged as the pasting electrode 4 at an interval of 40 mm on both sides of the long side (100 mm side) of the substrate 3. In this state, the carbon heating element 1 having the carbon exothermic composition coating 2 formed thereon as described above was used as the test sample 1 (the size of the base material and the electrode was Production Example 4, Production Example 6, Production Example 8, The same applies to Production Example 11 and Production Example 13.)

In the spray coating, the following (1) to (8) were applied to the substrate as one cycle, and the carbon exothermic composition was applied twice (8 times application).
(1) A base is placed flat on a rotatable base with the surface on which electrodes are arranged facing upward, and spray coating is performed on the surface.
(2) The substrate is rotated by 90 °.
(3) Spray coating as in (1).
(4) The base material is further rotated by 90 ° (from (1) in a state rotated by 180 °).
(5) Spray coating as in (1).
(6) The substrate is further rotated by 90 ° (from (1) to a state rotated by 270 °).
(7) Spray coating as in (1).
(8) The base material is further rotated by 90 ° (from (1) by 360 °).

[Test Example 1]
Performance Evaluation of Carbon Heating Element (1) (Relationship between Graphite and Carbon Nanotube Mixing Ratio and Carbon Component and Binder Mixing Ratio):
With respect to the test sample prepared as described above, the applied voltage was set to 12 V, and the temperature rise after 1 minute when the voltage was applied was confirmed and compared and evaluated. The results are shown in Table 1 together with the composition.

In addition, as a standard of evaluation, the temperature rise after 1 minute is 9 ° C. or more as a guide for heat generation efficiency, and when the temperature rise is 9 ° C. or more, the heat generation efficiency is excellent. (The same applies to Test Examples 2 to 4, Test Example 6, and Test Example 7). In addition, G / CNT (mass ratio, the same applies hereinafter), which is a blending ratio of graphite and carbon nanotube in Table 1, etc., is a numerical value rounded off to the second decimal place for convenience.

(Composition and evaluation results)

As shown in Table 1, the carbon component is in the range of 50 to 300 parts by mass with respect to 100 parts by mass of the binder, and the compounding ratio of graphite and carbon nanotubes is in the range of graphite / carbon nanotubes = 2.5 to 5.4. The carbon heating element in which the carbon exothermic composition of Example 1 to Example 11 was used as a film had excellent heat generation efficiency.

[Production Example 3]
Production of carbon exothermic composition (2):
The following components were blended in the composition shown in Table 2 as binders dissolved in graphite, carbon nanotubes (dispersed), and a solvent, and the carbon components were dispersed in a binder that was mixed and dissolved in the solvent. The carbon exothermic compositions of Example 1a, Example 12 and Example 13 were obtained. Note that Example 1a has the same composition as Example 1. In Example 12, a mixed system of epoxy resin (EP) + phenolic resin (PF) is used as a binder.

(Binder (solvent resin))
(1) Polyurethane resin (UR) (polyurethane resin dissolved in a solvent (mixed solvent of MEK (methyl ethyl ketone), butyl acetate, n-butanol, IPA (isopropyl alcohol)))
(2) Mixed system of epoxy resin (EP) + phenolic resin (PF) (epoxy resin + phenolic resin dissolved in solvent (mixed solvent of xylene, ethylbenzene, MEK, n-butanol, phenol) .)
(3) Polyamideimide resin (PAI) (polyamideimide resin dissolved in solvent (mixed solvent of DMF (dimethylformamide), NMP (n-methylpyrrolidone), MEK, IPA))

[Production Example 4]
Production of carbon heating element (2):
The carbon exothermic composition obtained in Production Example 3 was disposed on both sides of the long side by using the same method as in Production Example 2 (the substrate and the temperature conditions in firing were described later). A planar carbon heating element (test sample) in which a film of an electrode and a carbon heating composition was formed on one side of a substrate (polycarbonate sheet, size: 100 mm × 50 mm × 2 mm) was formed. When the binder is a polyurethane-based resin (UR), as in Production Example 2, the base material is a polycarbonate sheet, and the temperature condition in firing (hereinafter sometimes simply referred to as “temperature condition”) is 80 ° C. × 60 minutes. However, for a mixed system of epoxy resin (EP) + phenolic resin (PF), the base material is a polyphenol sheet, the temperature condition is 150 ° C. × 60 minutes, and the polyamideimide resin (PAI) is a base material. Was performed at a temperature of 190 ° C. for 60 minutes.

[Test Example 2]
Performance evaluation of carbon heating element (2) (Relationship with binder type):
Using the same method as in Test Example 1, the applied voltage was set to 12 V on the test sample, and the rising temperature after 1 minute when the voltage was applied was confirmed and compared and evaluated. The results are shown in Table 2 together with the composition.

(Composition and evaluation results)

As shown in Table 2, the carbon heating elements in which the carbon heating compositions of Example 1a, Example 12 and Example 13 using a polyurethane resin or the like as a binder are coated, and are excellent in heat generation efficiency. A resin using a polyamide resin or a polyamide-imide resin gave particularly excellent results.

[Production Example 5]
Production of carbon exothermic composition (3):
The following components were blended in the composition shown in Table 3 as binders dissolved in graphite, carbon nanotubes (dispersed), and a solvent, and the carbon components were dispersed in a binder dissolved in the solvent after mixing. The carbon exothermic compositions of Example 1b and Examples 14 to 17 were obtained. In addition, Example 1b is a composition common to Example 1.

(Carbon component)
(1) Graphite-1 (G-1) (flaky graphite, average particle size: 10 μm)
(2) Graphite-2 (G-2) (scale graphite, average particle size: 1 μm)
(3) Graphite-3 (G-3) (scaled graphite, average particle size: 10 μm)
(4) Graphite-4 (G-4) (artificial graphite, average particle size: 20 μm)
(5) Carbon nanotube (CNT) (average length (fiber length) 6 μm, average outer diameter (fiber diameter) 100 nm, multilayer)

(Binder (solvent resin))
(1) Polyurethane resin (UR) (Polyurethane resin dissolved in solvent (MEK (methyl ethyl ketone), butyl acetate, n-butanol, IPA (isopropyl alcohol) mixed solvent))

[Production Example 6]
Production of carbon heating element (3):
Using the same method as in Production Example 2, the carbon exothermic composition obtained in Production Example 5 was a base material (polycarbonate sheet, size: 100 mm × 50 mm × 2 mm) provided with electrodes made of aluminum tape on both long sides. A sheet-like carbon heating element (test sample) in which an electrode and a coating of the carbon heating composition were formed on one side was formed.

[Test Example 3]
Performance evaluation of carbon heating element (3) (Relationship with graphite type):
Using the same method as in Test Example 1, the applied voltage was set to 12 V on the test sample, and the rising temperature after 1 minute when the voltage was applied was confirmed and compared and evaluated. The results are shown in Table 3 together with the composition.

(Composition and evaluation results)

As shown in Table 3, the carbon heating elements using the carbon exothermic compositions of Example 1b and Examples 14 to 17 using scaly, scaly, and artificial graphite as the graphite have excellent heat generation efficiency. In particular, those having only the scale shape (G-1) and those using artificial graphite (G-4) gave particularly excellent results.

[Production Example 7]
Production of carbon exothermic composition (4):
Carbon component graphite, carbon nanotubes (dispersed), silicon carbide, the following materials as binders dissolved in a solvent are blended in the composition shown in Table 4 and mixed to dissolve the carbon component in the solvent. Dispersed carbon exothermic compositions of Example 18 and Example 19 were obtained.

(Carbon components, etc.)
(1) Graphite-1 (G-1) (flaky graphite, average particle size: 10 μm)
(2) Carbon nanotube (CNT) (average length (fiber length) 6 μm, average outer diameter (fiber diameter) 100 nm, multilayer)
(3) Silicon carbide (SiC) (average particle size: 700 nm)

[Production Example 8]
Production of carbon heating element (4):
Using the same method as in Production Example 2, the carbon exothermic composition obtained in Production Example 7 was made of a base material (polycarbonate sheet, size: 100 mm × 50 mm × 2 mm) on both sides of the long side. A sheet-like carbon heating element (test sample) in which an electrode and a coating of the carbon heating composition were formed on one side was formed.

[Test Example 4]
Performance evaluation of carbon heating element (4) (Relationship with silicon carbide addition):
Using the same method as in Test Example 1, the applied voltage was set to 12 V on the test sample, and the rising temperature after 1 minute when the voltage was applied was confirmed and compared and evaluated. The results are shown in Table 4 together with the composition. In Table 1, the measurement results of Example 1 are also shown as blanks.

(Composition and evaluation results)

As shown in Table 4, the carbon heating element having the carbon exothermic composition of Example 18 and Example 19 to which silicon carbide was added as a coating had better heat generation efficiency than Example 1 to which no silicon carbide was added. .

[Production Example 9]
Production of carbon heating element (5)
The carbon exothermic composition obtained in Example 1 was made of a polycarbonate sheet and a nylon 6 sheet (both sizes: 100 mm × 50 mm × 2 mm), which are substrates having electrodes made of aluminum tape having a thickness of 130 μm arranged on both sides of the long side. ) And spray-coating by the same method as shown in Production Example 2, and then baking and drying at 80 ° C. for 60 minutes using a high-temperature incubator (Temperature Equipment Laboratory). Then, a planar carbon heating element (test sample) in which a film of an electrode and a carbon heating composition was formed on one side of the substrate was formed. The film thickness of the carbon exothermic composition was adjusted to 30 to 50 μm.

[Test Example 5]
Performance evaluation of carbon heating element (5) (Relationship with substrate type):
When a voltage was applied to the test sample obtained in Production Example 9 using two kinds of applied voltages of 12 V and 24 V, the relationship between the application time and the rising temperature was confirmed, and the base material was polycarbonate sheet and nylon. The difference in the case of 6 sheets was compared and evaluated. The results are shown in FIG.

FIG. 3 is a graph showing the relationship between the application time and the rising temperature in Test Example 5. As shown in FIG. 3, the polycarbonate sheet (indicated as PC in FIG. 3) as the base material had a higher rising temperature and excellent heat generation efficiency than the nylon sheet as the base material.

[Production Example 10]
Production of carbon exothermic composition (5):
The following components were blended in the composition shown in Table 5 as binders dissolved in graphite, carbon nanotubes (dispersed), and a solvent, and the carbon components were dispersed in a binder that was mixed and dissolved in the solvent. The carbon exothermic compositions of Example 20 and Comparative Example 7 were obtained. In Example 20 and Comparative Example 7, fluororubber (F) added with a crosslinking agent and crosslinked was used as a binder.

(Carbon component)
(1) Graphite-1 (G-1) (flaky graphite, average particle size: 10 μm)
(2) Carbon nanotube (CNT) (average length (fiber length) 6 μm, average outer diameter (fiber diameter) 100 nm, multilayer)

(Binder (solvent resin))
(1) Fluororubber (F) (Fluororubber dissolved in a solvent (a mixed solvent of anone (cyclohexanone) and butyl acetate))

[Production Example 11]
Production of carbon heating element (6):
Using the same method as in Production Example 2, the carbon exothermic composition obtained in Production Example 10 was provided on one side of a base material (size: 100 mm × 50 mm × 2 mm) on both sides of the long side. A planar carbon heating element (test sample) having an electrode and a coating of the carbon heating composition formed thereon was formed. In Production Example 2, the substrate was changed to a polyphenol sheet, and the temperature condition was changed to 150 ° C. × 60 minutes.

[Test Example 6]
Performance evaluation of carbon heating element (6) (when fluororubber is used as binder):
Using the same method as in Test Example 1, the applied voltage was set to 12 V on the test sample, and the rising temperature after 1 minute when the voltage was applied was confirmed and compared and evaluated. The results are shown in Table 5 together with the composition.

(Composition and evaluation results)

As shown in Table 5, the carbon component is in the range of 50 to 300 parts by mass with respect to 100 parts by mass of the fluororubber as a binder, and the compounding ratio of graphite and carbon nanotube is graphite / carbon nanotube = 2.5 to 5 The carbon heating element in which the carbon heating composition of Example 20 in the range of .4 was coated was excellent in heating efficiency.

[Production Example 12]
Production of carbon exothermic composition (6):
The following components were blended in the composition shown in Table 6 as binders dissolved in graphite, carbon nanotubes (dispersed), and a solvent, and the carbon components were dispersed in a binder that was mixed and dissolved in the solvent. The carbon exothermic compositions of Examples 21 to 23 were obtained. In Examples 21 to 23, a polyamide-imide resin (PAI-2) (having a different skeleton and structure from the polyamide-imide resin (PAI) constituting Example 13) is used as a binder. Yes.

(Binder (solvent resin))
(1) Polyamideimide resin (PAI-2) (polyamideimide resin dissolved in a solvent (mixed solvent of DMF (dimethylformamide), DMAC (dimethylacetamide), NMP (N-methylpyrrolidone)). )

[Production Example 13]
Production of carbon heating element (7):
Using the same method as in Production Example 2, the carbon exothermic composition obtained in Production Example 12 was provided on one side of a base material (size: 100 mm × 50 mm × 2 mm) having electrodes made of aluminum tape disposed on both sides of the long side. A planar carbon heating element (test sample) having an electrode and a coating of the carbon heating composition formed thereon was formed. In Production Example 2, the substrate was changed to a polyphenol sheet and the temperature condition was changed to 190 ° C. × 60 minutes.

[Test Example 7]
Performance evaluation of carbon heating element (7) (when polyamideimide resin is used as binder):
Using the same method as in Test Example 1, the applied voltage was set to 12 V on the test sample, and the rising temperature after 1 minute when the voltage was applied was confirmed and compared and evaluated. The results are shown in Table 6 together with the composition.

(Composition and evaluation results)

As shown in Table 6, the carbon heating element in which the carbon exothermic composition of Examples 21 to 23 using a polyamideimide resin as a binder was used as a film had excellent heat generation efficiency.

[Production Example 14]
Production of carbon heating element (8):
A base material (polyetherimide) having the carbon exothermic composition of Example 20 having a length of 100 mm to 200 mm and a thickness of 2 mm to 25 μm in FIG. 1 and FIG. (PEI) film, size: width 50 mm × length 200 mm × 25 μm) One side (surface on which electrodes are arranged) 3 is spray coated in the same manner as in Production Example 2, and after spray coating, baked at 150 ° C. for 60 minutes. Forming the film by drying, a sheet-like carbon heat generation in which an electrode 4 (electrode length, 200 mm, distance between electrodes: 40 mm) and a film 2 of a carbon heat generation composition having a thickness of 85 μm are formed on one surface of the substrate 3 Body 1 (Test Sample 1) was formed.

[Test Example 8]
Performance evaluation of carbon heating element (8):
Two commercially available aluminum bottle containers for beverages (inner diameter: 63 mm, capacity: 300 ml) were prepared, 100 ml (100 g) in one, 200 ml (200 g) in one, and water at room temperature. The carbon heating element 1 (test sample 1) obtained in Production Example 14 was wrapped around the side surface of the container, and the change in water temperature when 12 V was applied to the carbon heating element 1 was measured with respect to time. The results are shown in FIG.

FIG. 4 is a diagram showing the relationship between the application time and the rising temperature in Test Example 8. As shown in FIG. 4, an increase in the water temperature was observed corresponding to the application time, and it was confirmed that it could be used for the purpose of heating the target medium (water). Moreover, since it was possible to heat the target medium with an applied voltage of 12V, it was also confirmed that it could be used with a vehicle-mounted voltage (12V).

The present invention can be advantageously used as a means for providing a carbon heating element excellent in thermal efficiency, and has high industrial applicability.

1 Carbon heating element (test sample)
2 Coating of carbon exothermic composition 3 Base material 4 Electrode

Claims

A carbon exothermic composition in which a powdery carbon component is dispersed in a binder,
The carbon component includes graphite and carbon nanotubes,
The mixing ratio of the graphite and the carbon nanotube is graphite / carbon nanotube = 2.5 to 5.4,
A carbon exothermic composition comprising 50 to 300 parts by mass of the graphite and the carbon nanotubes in total with respect to 100 parts by mass of the binder.
The carbon exothermic composition according to claim 1, further comprising powdered silicon carbide.
The carbon exothermic composition according to claim 1 or 2, wherein the binder is at least one selected from a polyurethane resin, a polyamideimide resin, and a fluororubber.
A carbon heating element, which is a film made of the carbon heating composition according to any one of claims 1 to 3.
The carbon heating element according to claim 4, wherein the coating is formed on a predetermined base material.
The carbon heating element according to claim 5, wherein the heating element is a planar heating element in which the coating is formed on the planar substrate.