JP2010045025A - Exothermic body using fine carbon fiber, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exothermic body which has high exothermic efficiency and is applicable, in a low temperature region of 100°C or lower, to an electric carpet of energy saving type, a floor heater, a wall heating unit, snow-melting of roads and roofs and demisting heater of a mirror, and, in a region of 100 to 200°C, evaporates and dries moisture attached on a material surface in a manufacturing process of silicon wafers, and provide an exothermic heater, an exothermic fixing roller or a belt used for a fixing part in a copying machine and a laser beam printer in a high temperature region of 200°C or higher. <P>SOLUTION: In the exothermic body and a manufacturing method thereof, an electrically conductive portion in which fine carbon fibers are dispersed in a resin material and an inter-electrode resistance value is 1×10<SP>5</SP>Ω/cm or less is applied to an exothermic layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a heating element using a fine carbon fiber and a resin material and having a conductive part having an interelectrode resistance (Ω / cm) of 105 or less as a heating layer, and a method for producing the heating element. In the following low-temperature regions, it can be used for floor heating, wall heating equipment, snow melting on roads and roofs, or anti-fogging heaters for mirrors, or heaters used for heating and heat retaining pipelines. Further, in the region of 100 ° C. to 200 ° C., it can be used as a heating element for volatilizing and drying the moisture adhering to the material surface in the silicone wafer manufacturing process or the like. Furthermore, in a high temperature region of 200 ° C. or higher, it can be used as a heating heater, a heating fixing roller or a belt used in a fixing unit in a copying machine and a laser printer.

The fine carbon fiber is a material typified by vapor grown carbon fiber, carbon nanofiber, carbon nanotube and the like.

Among them, carbon nanotubes have a fiber diameter of 100 nm or less, and have unprecedented chemical properties, electrical properties, mechanical properties, thermal conductivity, structural properties, etc. , Electronic devices, electrical wiring, electrothermal conversion element materials, thermoelectric conversion element materials, heat radiation materials for building materials, electromagnetic wave shielding materials, radio wave absorption materials, field emission cathode materials for flat panel displays, electrode bonding materials, resin composite materials, transparent conductive films Application to catalyst support materials, electrodes / hydrogen storage materials, reinforcing materials and black pigments is expected.

The types of carbon nanotubes include single carbon nanotubes (SWCNT) in which a single layer of carbon atoms bonded in a network (graphene sheet) is formed into a cylinder, double carbon nanotubes (DWCNT) in which two layers are formed in a tube, and graphene Multi-walled carbon nanotubes (MWCNTs) in which multiple layers of sheet cylinders are nested are known.

In addition, the diameter and the geometric shape of the sheet winding are determined by the chiral index, and the carbon nanotube shows the properties of metals and semiconductors by the chiral index.

Multi-walled carbon nanotubes are fibrils consisting of a continuous multi-layer of carbon atoms having a graphene structure, consisting of multiple layers of regularly arranged carbon atoms, with each layer and core substantially aligned with the central axis of the fibril. For example, Patent Documents 1, 2, and 3 disclose fibrils made of graphite orthogonal to the above.

However, in a laminated structure of concentric graphene sheets, the fibers are easily deformed, the fibers are aggregated by van der Waals force, and a structure in which the fibers are entangled with each other easily. Therefore, when carbon nanotubes having such an agglomerated structure are mixed and dispersed in a matrix material as a filler for a composite material, the intertwined agglomerated fibers are not easily unwound and are difficult to disperse. there were.

Carbon nanotubes that are difficult to mix and disperse in water, organic solvents or matrix materials (thermoplastic and thermosetting resin solutions, rubber solutions, thermoplastic and thermosetting resins, rubber) as fillers for composite materials. Methods for improving the state include a method of improving the dispersibility by changing the shape of the carbon nanotube or the degree of graphitization of the surface, a method of modifying the surface of the carbon nanotube by chemical treatment, and a dispersing agent as the third component , Ie, the type of dispersant, the optimization of the addition amount, and the type of the disperser, and the method of optimizing the operating conditions.

As a method for improving the dispersibility by changing the shape of the carbon nanotube or the degree of graphitization of the surface, Patent Documents 4 to 6 as reports on improving the shape, and Non-Reference Document 1 as a report of changing the degree of graphitization of the surface. Is published. The carbon nanotube of Patent Document 4 is a fine carbon fiber that can improve physical properties such as electrical properties, mechanical properties, thermal properties, etc., without impairing the properties of the matrix, with a small amount of addition. Graphene sheets are laminated in a direction perpendicular to the axis, the sheet constituting the cylinder has a polygonal axis orthogonal cross section, the maximum diameter of the cross section is 15 to 100 nm, the aspect ratio is 105 or less, and Raman spectroscopic analysis The R value measured at 514 nm is 0.1 or less.

The carbon nanotube of Patent Document 5 is a three-dimensional network-like fine carbon fiber structure composed of fine carbon fibers having an outer diameter of 15 to 100 nm, and the fine carbon fiber structure bonds the fine carbon fibers to each other. And a granular portion having a particle diameter larger than the outer diameter of the fine carbon fiber and having a decomposition temperature as a carbon source. By using at least two different carbon compounds, the carbon material grows in a fibrous form, while being formed by a growth process that also grows in the circumferential direction of the catalyst particles used. And

The carbon nanotube of Patent Document 6 is a fine carbon fiber structure that can improve physical properties such as electrical properties, mechanical properties, thermal properties, etc. without damaging the properties of the matrix with a small amount of addition, It is a three-dimensional network-like fine carbon fiber structure composed of fine carbon fibers having an outer diameter of 15 to 100 nm, and the fine carbon fiber structure has a granular portion for bonding the fine carbon fibers to each other. In a form in which a plurality of the fine carbon fibers extend from the granular part, the granular part has at least two or more particle diameters larger than the outer diameter of the fine carbon fiber and different decomposition temperatures as a carbon source. By using the carbon compound, the carbon material is formed in a growth process in which the carbon material grows in the form of fibers and also grows in the circumferential direction of the catalyst particles used. Carbon fiber structure, characterized in that the powder resistance value measured in pressed density 0.8 g / cm @ 3 is less than 0.02 ohm · cm.

In Non-Patent Document 1, an organic compound such as hydrocarbon is subjected to a chemical pyrolysis reaction by a CVD method using transition metal ultrafine particles as a catalyst to obtain a fiber structure. Thereafter, the fiber structure is heat-treated at a high temperature to increase the graphitization degree of the carbon nanotube. And the method of setting the high temperature processing temperature of a fiber structure to the processing temperature which becomes the required graphitization degree, and controlling the graphitization degree of the carbon nanotube obtained is shown.

Patent Documents 7 to 12 and Non-Patent Documents 2-3 are disclosed as methods for optimizing the type of dispersant and the amount of addition and / or the type of disperser and the operating conditions. Patent Document 7 discloses that a water-soluble solvent, an organic solvent, or a mixed solvent thereof can be used as a dispersion solvent for carbon nanotubes. For example, water, acidic solution, alkaline solution, alcohol, ether, petroleum ether, benzene, ethyl acetate, chloroform, isopropyl alcohol, ethanol, acetone, toluene and the like.

Patent Document 8 also discloses a method of dispersing carbon nanotubes in a mixed solvent of N-methylpyrrolidone that is an amide polar organic solvent and polyvinylpyrrolidone that is a polymer solvent.

Patent Document 9 also discloses a method of dispersing carbon nanotubes using a polyester acid amide amine salt as a dispersant in a hydrocarbon solvent as a basic polymer.

Non-Patent Document 2 discloses a method for producing a carbon nanotube aqueous dispersion using a nonionic surfactant. A proposal using Tergitol ™ NP7 as the nonionic surfactant has been made, but it is reported that when the amount of carbon nanotubes increases, the carbon nanotubes aggregate and a uniform dispersion cannot be obtained. Has been.

In Non-Patent Document 3, a single-walled carbon nanotube is ultrasonically treated in an anionic surfactant SDS aqueous solution to adsorb the hydrophobic surface of the carbon nanotube and the hydrophobic portion of the surfactant, and the hydrophilic portion on the outside. Have been reported to form and disperse in aqueous solutions

In Patent Document 10, an amphoteric molecule is attached to at least a part of each carbon nanotube constituting a plurality of carbon nanotube bundles, and the amphoteric molecule attached to the carbon nanotube constituting one carbon nanotube bundle among the plurality of carbon nanotube bundles. However, by electrically attracting the amphoteric molecules attached to the carbon nanotubes constituting other adjacent carbon nanotube bundles, the carbon nanotubes constituting the plurality of carbonized tube bundles are isolated and dispersed to produce a paste. A method for producing a carbon nanotube-dispersed paste is shown.

In Patent Document 11, a nanocarbon containing a surfactant capable of forming spherical micelles having a diameter of 50 to 2000 nm in an aqueous solution or a water-soluble polymer having a weight average molecular weight of 10,000 to 50 million as an active ingredient. A water solubilizer is disclosed. Examples of nanocarbon include carbon nanotubes (single-layer, multi-layer, cup-stack type) and the like. The surfactant is a phospholipid-based or non-phospholipid-based surfactant. For example, distearoylphosphatidylcholine (DSPC), dimyristoylphosphatidylcholine (DMPC), dipalmitylphosphatidylcholine (DPPC), 3-[(3-cola One or more selected from the group consisting of (midopropyl) dimethylamino] -2-hydroxy-1-propanesulfonic acid (CHAP) and N, N-bis (3-D-gluconamidopropyl) -colamide. ing. Examples of the water-soluble polymer include plant surfactants such as water-soluble polysaccharides and alginic acids such as alginic acid, propylene glycol alginate, arabian gum, xanthan gum, hyaluronic acid, and chondritin sulfate. Examples of water-soluble celluloses include cellulose acetate, methyl cellulose, hydroxypropyl methyl cellulose, chitosan, and chitin. Examples of water-soluble proteins include gelatin and collagen. Polyoxyethylene / polyoxypropylene block polymers, DNA, and the like are also used.

In Patent Document 12, when a fine carbon-dispersed liquid medium containing nano to micro-sized fine carbon and a dispersant for the fine carbon is applied to a hydrophobic smooth body when the liquid medium is aqueous, it is dried, When the liquid medium is non-aqueous, it is dried after being applied to a hydrophilic smooth body. In some cases, a reticulated nanocarbon aggregate obtained by washing the dispersant after drying is disclosed.

US Pat. No. 4,663,230 Japanese Patent Laid-Open No. 03-174018 US Pat. No. 5,165,909 Japanese Patent No. 3761561 JP 2006-265751 A Japanese Patent No. 3776111 Japanese Patent Laid-Open No. 2000-72422 JP 2005-162877 A JP 2006-63436 A JP 2007-39623 A WO2004 / 060798 JP 2007-182363 A J. et al. Chen et al. Carbon 45, 2007, 274-280 S. Cui et al. Carbon 41, 2003, 797-809 Michael J.M. O'Connel et al. SCIENCE VOL297 26 July 2002, 593-596

On the other hand, an application example in which a conductive material is applied to an electrothermal conversion material has also been reported. For example, Patent Documents 13 to 16 disclose heating elements using carbon black. In the heating element of Patent Document 13, in a sheet-like self-temperature control type surface heating element having a characteristic that the resistance temperature coefficient increases in a positive direction in a specific temperature region, the heating element is formed between electrodes provided at both ends. It is a self-temperature-controlled surface heating element configured such that the thickness of the conductive portion is gradually increased toward the central portion. Carbon black is used as the conductive material, and low molecular weight polyolefin wax is used as the matrix resin.

The heating element of Patent Document 14 is a planar heating material formed by molding a heating composition having a thermoplastic resin and conductive particles into a planar shape, and the specific resistance value of at least a part of the region is other than that. It is a planar heat generating material different from the specific resistance value of the region. The conductive particles are carbon black, and the thermoplastic resin is an ethylene-ethyl acrylate copolymer.

In the heating element of Patent Document 15, 100 parts by weight of polyurethane (A), 70 to 120 parts by weight of carbon black (B) having a dibutyl phthalate oil absorption of 100 ml / 100 g or less, and carbon black having a dibutyl phthalate oil absorption of 150 ml / 100 g or more. (C) A planar heating element comprising a conductive composition comprising 1 to 30 parts by weight, a conductive paint, a conductive fiber material and a conductive fiber material coated therewith.

The heating element of Patent Document 16 is a planar heating element in which a conductive material composed of graphite and carbon black is mixed and dispersed in a synthetic resin dispersion medium mainly composed of a fluororesin. The sheet heating element is characterized in that it is a planar heating element in which graphite having a predetermined fine particle diameter and carbon black are mixed and dispersed in a desired ratio.

Furthermore, Patent Documents 17 to 24 disclose heating elements that use fine carbon fibers that are less conductive and tar than carbon black and have high heat resistance as an electrothermal conversion material. The heating element of Patent Document 17 is a functional coating agent composition characterized in that one or both of carbon nanotubes and carbon nanocoils are blended with a film forming component. As a composition, a) a composition in which organopolyoxysiloxane is a main component and an organokiloxan having a functional side chain as a crosslinking agent and a curing catalyst are blended; and b) a solvent for high heat is blended in ceramic particles. Composition, c) organic solvent solution of perhydropolysilazane, d) prepolymer prepared by reacting low molecular weight glycidyl ether type epoxy resin in the presence of metal oxide powder using catalyst Yes.

The heating element of Patent Document 18 is a planar heating element in which a conductive layer made of conductive powder and a binder resin, and an insulating layer made of thermoplastic or thermosetting resin are bonded to one or both sides of the conductive layer. It is characterized by. Although carbon nanotubes are used as the conductive powder, no heat generation characteristic evaluation results are described in the examples.

The heating element of Patent Document 19 is characterized in that it is an organic PTC composition in which a carbon nanotube and a conductive metal and / or a conductive metal compound are dispersed in a crystalline organic polymer.

The heat generating element of Patent Document 20 has a heat absorption / heat dissipation characteristic in which the thermal conductivity of a coating layer including fine carbon fibers having an average aspect ratio of 3 or more is 1 W / m · K or more on at least a part of a metal material surface. It is characterized by being an excellent surface-treated metal material. Fine carbon fibers are carbon nanotubes having a fiber diameter of 10 μm or less, an epoxy resin or silicone resin as a matrix, and a plated steel material, a vinegar-less steel material, a titanium material, an aluminum material, or an aluminum alloy material as a metal material.

The heating element of Patent Document 21 is characterized in that it is a heat conductor including at least a heat conductive fiber provided with carbon nanotubes. The carbon nanotube dispersion to be sprayed on the heat conductive fiber is carbon nanotube, conductive material is alkylbenzene sulfonic acid and / or alkyl ether sulfate, hydrophilic part is hydroxyl group, ethylene oxide, carbon-carbon triple bond, ionicity It is a compound having a structure of a hydrophobic part-hydrophilic part-hydrophobic part which is one of the groups.

The heating element of Patent Document 22 has an average resistivity of 1.0 × 10 6 to 1.0 × 10 12 [Ω / cm] having a conductive layer in at least a part of the fiber layer, and a standard deviation of the resistivity of 0. 2 or less conductive fibers, wherein the conductive layer is a conductive fiber comprising at least a polyester component and carbon nanotubes. Polyester is a polymer having trimethylene terephthalate as the main repeating structural unit.

The heating element of Patent Document 23 includes a heating layer in which a conductive material made of carbon nanomaterials and filamentary metal fine particles is dispersed substantially uniformly in a matrix resin made of polyimide, and an electric power is supplied to the heating layer. It is characterized by a planar heating element formed by laminating an electrode for supplying heat, the heat generating layer, and an insulating layer covering the electrode. As carbon nanomaterials, carbon nanofibers, carbon nanotubes, carbon microcoils, filamentary metal fine particles are at least 1 as nickel fine particles having a shape in which strands are three-dimensionally connected, matrix resin made of polyimide, and insulating layer A polyimide obtained by imide conversion of a polyimide precursor obtained by polymerizing a kind of aromatic diamine and at least one kind of aromatic tetracarboxylic dianhydride in an organic polar solvent is shown.

The heating element of Patent Document 24 is a thin film resistance heating element formed by applying a coating agent composition in which one or both of carbon nanotubes and carbon microcoils are blended in a film forming component to a base material and curing it. It is characterized by things. As a composition, a) a composition in which organopolyoxysiloxane is a main component and an organokiloxan having a functional side chain as a crosslinking agent and a curing catalyst are blended; and b) a solvent for high heat is blended in ceramic particles. Composition, c) an organic solvent solution of perhydropolysilazane, d) a prepolymer prepared by reacting a low molecular weight glycidyl ether type epoxy resin in the presence of a metal oxide powder using a catalyst.

JP-A-01-151191 JP 08-264268 A JP 2006-202575 A JP 2006-073217 A Japanese Unexamined Patent Publication No. 2000-026760 JP 2002-077562 JP 2003-163104 A Japanese Patent Laid-Open No. 2005-199666 JP 2004-103766 A JP 2007-092234 A JP 2007-109640 A JP 2000-058228 A

As described above, a plurality of techniques for making a heating element using chemical characteristics, electrical characteristics, and thermal conductivity unique to carbon nanotubes have been disclosed. However, in order to maximize the electrical characteristics and thermal conductivity specific to carbon nanotubes, it is necessary to use carbon nanotubes with a high degree of graphitization, but studies that refer to these have not been made. In addition, regarding the base material forming the heating element, no heating element produced by applying or printing on paper, film, rubber, glass, glass fiber, ceramic, gypsum, resin or the like has been reported.

The present invention provides a heating element in which fine carbon fibers are dispersed in a resin material and a conductive part having an interelectrode resistance (Ω / cm) of 105 or less is applied to a heating layer, and a method for manufacturing the heating element. Objective.

In order to solve the above-mentioned problems, the present invention has been intensively studied. As a result, a heating element in which fine carbon fibers are dispersed in a resin material and a conductive portion having an interelectrode resistance (Ω / cm) of 105 or less is applied to a heating layer. And it was set as the structure of the manufacturing method of a heat generating body.

The fine carbon fiber had a R value of 1.0 or less by Raman spectroscopic analysis.

The fine carbon fiber had a R value of 0.7 or less by Raman spectroscopic analysis.

The fine carbon fiber had a R value of 0.2 or less by Raman spectroscopic analysis.

The heat generating element is characterized in that the resin material is a thermoplastic resin.

The heat generating element is characterized in that the resin material is a thermosetting resin.

The resin material is an elastomer material.

The resin material is a printing ink.

The heat generating element is characterized by being obtained by molding, curing, or applying the resin material containing the fine carbon fiber to a base material.

The heat generating element is characterized in that a fine carbon fiber dispersant is added to the resin material containing the fine carbon fibers.

The fine carbon fiber dispersant contains at least one type of polymer-based dispersant.

The heating element has a configuration in which the polymer dispersant is a polyvinyl butyral resin.

It was set as the structure of the heat generating body characterized by the said polymer dispersing agent being 0.0005-100 mass parts with respect to 100 mass parts of fine carbon fiber.

The base material is a material selected from the group consisting of paper, rubber, glass, glass fiber, ceramic, gypsum, thermoplastic resin or thermosetting resin.

The heat generating element has a structure in which 0.1 to 30 parts by mass of fine carbon fiber is added to 100 parts by mass of the resin material.

The heat generating element is characterized in that the fine carbon fibers are composed of fine carbon fibers having an average outer diameter of 10 to 300 nm.

The fine carbon fiber has a single layer structure, a double layer structure, or a multilayer structure.

The fine carbon fiber is a three-dimensional network-like fine carbon fiber structure composed of fine carbon fibers having an average outer diameter of 10 to 300 nm, and the fine carbon fiber structure has a plurality of granular parts, In a mode in which the plurality of fine carbon fibers extend with a three-dimensional extension from the granular part, the fine carbon fiber is at least partially formed by a mode in which the extending fine carbon fiber is also bonded to other granular parts. The heating element is characterized by having a three-dimensional network structure.

By using at least two or more carbon compounds having a particle diameter larger than the outer diameter of the fine carbon fiber and having different decomposition temperatures as carbon sources, While the material is grown in the form of a fiber, it is formed in a growth process in which the material is grown in the circumferential direction of the catalyst particles to be used.

The fine carbon fiber is composed of fine carbon fibers having an average outer diameter of 15 to 100 nm.

The fine carbon fiber was a high-purity fine carbon fiber having a tar content of 0.5% or less.

The heating element has a heating layer having a thickness of 0.3 mm or less.

The heating element has a configuration in which electrodes are provided at both ends of the heating layer of the heating element.

The heating element is manufactured by applying the resin material containing the fine carbon fiber to a base material to manufacture a heat generating layer, and the applied heat generating layer is cured or dried. .

In the method for manufacturing a heating element, the method includes a step of forming an electrode on the heating layer.

In the manufacturing method of the heating element, the heating element and the electrode are covered with a resin material, and an insulating layer forming step is provided.

The present invention has the above-described configuration and can be used as a heating element, as well as the following effects. In the Raman spectroscopic analysis according to the present invention, electric energy having an R value of 1.0 or less containing fine carbon fiber and a resin material, and having a conductive portion having an interelectrode resistance (Ω / cm) of 105 or less as a heat generation layer The heating element that converts to thermal energy shows higher heat generation characteristics at a lower voltage than the fine carbon fiber whose R value is 1.0 or more in Raman spectroscopic analysis, and this characteristic increases as the area of the heating element increases. Appears prominently. Therefore, it is possible to generate heat with various generators, automobile batteries or dry batteries, as well as with AC 100V as a household power source.

Further, the conductive portion containing fine carbon fibers and resin materials having an R value of 1.0 or less in the Raman spectroscopic analysis of the present invention and having an interelectrode resistance value (Ω / cm) of 105 or less is defined as a heating layer. The heating element that converts the electrical energy into thermal energy is characterized in that the rate of temperature rise after voltage application is fast. Therefore, when the heating element of the present invention is used for the fixing unit heating heater of a copying machine or a laser printer, the temperature can be increased immediately and the sleep mode can be used effectively. In addition, since it is not necessary to apply a low voltage, the power consumption of the copying machine and the laser printer can be reduced.

When high-purity multi-walled carbon nanotubes with a tar content of 0.5% or less according to the present invention are used, there is no volatilization of volatile components contained in the tar content when used as a heating element product. However, it can be made a safer heating element product.

Hereinafter, the present invention will be described in detail. Examples of the thermoplastic resin of the present invention include polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, chlorinated polyethylene resin, polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, polycarbonate resin, PC / ABS. Alloy resin, PC / AES alloy resin, ABS resin, ACS resin, AES resin, ASA resin, ABS / PVC alloy resin, polyacetal resin, liquid crystal polymer resin, fluorine resin, EVA resin, polyvinyl acetate resin, polybutadiene resin, polybutylene resin , Polymethylpentene resin, polyvinyl alcohol resin, cyclic olefin copolymer resin, silicone resin, polyamide resin, polyamide 610 resin, polyamide 612 resin, polyamide 46 Fatty, reinforced polyamide resin, acrylic resin, chlorinated polyethylene resin, chlorinated polypropylene resin, chlorinated polyolefin resin such as chlorinated ethylene-propylene copolymer, chlorinated ethylene-vinyl acetate copolymer, polystyrene resin, styrene-acrylic Copolymer, styrene-acetonitrile copolymer, nitrile resin, thermoplastic polyimide resin, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, styrene-maleimide copolymer, polyethylene terephthalate resin, polyester resin, acetic acid Vinyl resin, cyclic polyolefin copolymer, polyamideimide resin, polyamide bismaleimide resin, polyarylate resin, polyetherimide resin, polyetheretherketone resin, polyetherketone resin, polyethersulfone Resin, polyethylene oxide resin, polyvinylidene chloride resin, polyketone resin, polysulfone resin, polyetherimide resin, polyvinyl formal resin, polyvinyl acetal resin, polyphenylene ether resin, polyphenylene sulfide resin, polybenzimidazole resin, polyvinyl butyral resin, polyphenylene ether resin , Acrylic resin, thermoplastic polyurethane resin, silicone resin, cellulose acetate, cellulose nitrate, polylactic acid resin, and resins obtained by modifying these.

Examples of the thermosetting resin include unsaturated polyester resin (FRP), epoxy resin, phenol resin (PF), polyurethane resin (PU), amino resin such as urea resin, melamine resin, benzoguanamine resin, alginide resin, xylene Examples include resins, diallyl phthalate resins (DAP), bismaleimide triazine resins, bisester epoxy resins, polyimide resins, furan resins, and the like.

Examples of the elastomer material of the present invention include natural rubber and synthetic rubber such as acrylic rubber (ACM), acrylonitrile butadiene rubber (NBR), isoprene rubber (IR), urethane rubber (U), ethylene propylene rubber (EPM, EPDM), epichlorohydrin rubber (CO, ECO), silicone rubber (Q), styrene butadiene rubber (SBR), butadiene rubber (BR), fluoro rubber (FKM), polyisobutylene (IIR) and the like. Thermoplastic elastomer (TPE) materials include styrene (SBC), such as styrene-butadiene (SBS, SIS, SEBS), olefin (TPO), polyester (TPEE), such as PBT-PE-PBT, poly Examples include vinyl chloride (TPVC), polyurethane (TPU), and polyamide (TPAE).

Although the organic solvent used by this invention is mentioned below, it is not specifically limited to these. For example, alcohols (methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, cyclohexanol), glycols (ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, diethylene glycol monoethyl ether, polypropylene glycol monoethyl ether, polyethylene Glycol monoallyl ether, polypropylene glycol monoallyl ether, ethyl cellosolve, butyl cellosolve, carbitol, butyl carbitol, methoxybutanol) and ester ethers (cellosolve acetate, butyl cellosolve acetate, carbitol acetate, methoxybutyl acetate), ethers (tetrahydrofuran, dioxane) ), Aliphatic charcoal Hydrogen (mineral spirit), alicyclic hydrocarbon (turpentine oil), mixed hydrocarbon (HAWS, sorbet 100, sorbet 150), aromatic hydrocarbon (toluene, xylene, ethylbenzene,), ketones (acetone, methyl ethyl ketone, methyl) Isobutyl ketone, cyclohexanone, isophone), esters (ethyl acetate, butyl acetate, isobutyl acetate, amyl acetate), silicone oils (polydimethylsiloxane, partially octyl-substituted polydimethylsiloxane, partially phenyl-substituted polydimethylsiloxane), halogenated carbonization Examples include hydrogen (chlorobenzene, dichlorobenzene, chloroform, bromobenzene), fluorinated compounds, and the like. Two or more of these may be mixed. Furthermore, the amount of the solvent may be adjusted so as to have a viscosity suitable for use as a paint.

Examples of the fine carbon fiber of the present invention include single-walled, double-walled, and multi-walled carbon nanotubes, which can be used according to the purpose. In the present invention, more preferably, multi-walled carbon nanotubes are used. The carbon nanotube production method is not particularly limited, and any conventionally known production method such as a vapor phase growth method using a catalyst, an arc discharge method, a laser evaporation method and a HiPco method (High-pressure carbon monoxide process). The method may be used.

For example, a method for producing a single-walled carbon nanotube by laser vapor deposition is shown below. As a raw material, graphite powder and a mixed lot of nickel and cobalt fine powder were prepared. This mixed lot is heated to 1250 ° C. in an electric furnace under an argon atmosphere of 665 hPa (500 Torr), and irradiated with a second harmonic pulse of 350 mJ / Pulse Nd: YAG laser to evaporate carbon and metal fine particles. Thus, a single-walled carbon nanotube can be produced.

The above manufacturing method is merely a typical example, and the metal type, gas type, electric furnace temperature, laser wavelength, and the like may be changed. In addition, other than laser deposition methods, for example, HiPco method, vapor phase growth method, arc discharge method, carbon monoxide thermal decomposition method, template method in which organic molecules are inserted into fine pores, thermal decomposition, fullerene -You may use the single-walled carbon nanotube produced by other methods, such as a metal co-evaporation method.

For example, a method for producing a double-walled carbon nanotube by a constant temperature arc discharge method is shown below. The substrate was a surface-treated Si substrate, and the treatment method was a solution obtained by immersing alumina powder in a solution in which the catalyst metal and the catalyst auxiliary metal were dissolved for 30 minutes, and then dispersing by ultrasonic treatment for 3 hours. Was applied to a Si substrate and dried in air at 120 ° C. for maintenance. A substrate was installed in the reaction chamber of the carbon nanotube production apparatus, a mixed gas of hydrogen and methane was used as a reaction gas, the supply amount of gas was 500 sccm for hydrogen, 10 sccm for methane, and the pressure in the reaction chamber was 70 Torr. As the cathode part, a rod-like discharge part made of Ta was used. Next, a DC voltage was applied between the anode part and the cathode part, and between the anode part and the substrate, and the discharge voltage was controlled so that the discharge current was constant at 2.5A. When the temperature of the cathode part is 2300 ° C. due to discharge, the normal glow discharge state is changed to an abnormal glow discharge state, and the discharge current is 2.5 A, the discharge voltage is 700 V, and the reaction gas temperature is 3000 ° C. for 10 minutes. Single-walled and double-walled carbon nanotubes can be produced on the entire substrate.

The above manufacturing method is merely an example, and various conditions such as the type of metal and the type of gas may be changed. Moreover, you may use the single-walled carbon nanotube produced by production methods other than the arc discharge method.

For example, a method for producing a multi-walled carbon nanotube having a three-dimensional structure by vapor deposition is shown below. Basically, an organic compound such as a hydrocarbon is chemically pyrolyzed by a CVD method using ultrafine transition metal particles as a catalyst to obtain a fiber structure (hereinafter referred to as an intermediate). A multi-walled carbon nanotube having a high degree of graphitization can be produced by performing a high temperature annealing treatment at any temperature within the range.

The degree of graphitization of the multi-walled carbon nanotube obtained after the high-temperature annealing treatment is in the range of 1000 to 3000 ° C., and the higher the high-temperature annealing treatment temperature, the higher the degree of graphitization of the carbon nanotube.

As the raw material organic compound, hydrocarbons such as benzene, toluene and xylene, and alcohols such as carbon monoxide and ethanol are used, but it is preferable to use at least two or more carbon compounds having different decomposition temperatures as the carbon source. . Note that at least two or more carbon compounds do not necessarily use two or more types of raw material organic compounds, and even when one type of raw material organic compound is used, the fiber structure In the body synthesis process, for example, a reaction such as hydrogen dealkylation of toluene or xylene occurs, and in the subsequent thermal decomposition reaction system, it becomes two or more carbon compounds having different decomposition temperatures. Including embodiments. The atmosphere gas is an inert gas such as argon, helium, xenon or hydrogen, and the catalyst is a transition metal such as iron, cobalt or molybdenum, or a transition metal compound such as ferrocene or metal acetate, and sulfur or thiophene or iron sulfide. Use a mixture of sulfur compounds such as

The synthesis of the intermediate is carried out by using a CVD method such as hydrocarbon, which is usually performed, by evaporating the mixture of hydrocarbon and catalyst as raw materials, introducing hydrogen gas or the like into the reaction furnace as a carrier gas, Pyrolysis at a temperature of 1300 ° C. As a result, a plurality of fine carbon fiber structures (intermediates) having a sparse three-dimensional structure in which fibers having an average outer diameter of 10 to 300 nm are bonded together by granular materials grown using the catalyst particles as nuclei. Synthesize an aggregate of centimeters to tens of centimeters.

A three-dimensional network-like fine carbon fiber structure composed of fine carbon fibers having an average outer diameter of 10 to 300 nm has a plurality of granular portions, and the fine carbon fibers extend three-dimensionally from the granular portions. In an embodiment, the extending fine carbon fibers have at least partially a three-dimensional network structure of the fine carbon fibers, and the fine carbon fibers are bonded to each other according to an aspect in which the extending fine carbon fibers are also bonded to other granular portions. The granular part is made to grow a carbon substance into a fiber by using at least two or more carbon compounds having a particle size larger than the outer diameter of the fine carbon fiber and having different decomposition temperatures as a carbon source. On the other hand, it is formed in the growth process of growing in the circumferential direction of the catalyst particles used.

In determining the average outside diameter of the fine carbon fibers, the SEM was taken at 35,000 to 50,000 magnifications, photographs were taken with 3 or more fields of view, and random outside diameters of 200 or more fine carbon fibers were imaged. Measurement is performed using analysis software WinRoof (trade name, manufactured by Mitani Corporation), and a value calculated therefrom is used.

The average outer diameter of the fine carbon fiber is in the range of 10 to 300 nm. When the average outer diameter is less than 10 nm, the fine carbon fiber having a smaller outer diameter has a larger specific surface area and is dispersed. Since it tends to be difficult, it is difficult to achieve a uniform dispersion state, and the heat generation effect may not be sufficiently exhibited. On the other hand, when the average outer diameter exceeds 300 nm, the number of fine carbon fibers per unit amount is extremely small, and thus the resistance value between the electrodes of the heating element described later increases, and a high heat generation effect cannot be obtained.

In addition, the thermal decomposition reaction of the hydrocarbon as a raw material mainly occurs on the surface of the granular particles grown using the catalyst particles or nuclei as a nucleus, and the recrystallization of the carbon generated by the decomposition proceeds in a certain direction from the catalytic particles or granular materials. In this way, it grows in a fibrous form. However, by intentionally changing the balance between the thermal decomposition rate and the growth rate, for example, by using at least two or more carbon compounds having different decomposition temperatures as a carbon source as described above, the carbon material is only in a one-dimensional direction. Without growing the carbon material, the carbon material can be grown three-dimensionally around the granular material. Of course, the growth of such three-dimensional carbon nanotubes does not depend only on the balance between the thermal decomposition rate and the growth rate, but the crystal surface selectivity of the catalyst particles, the residence time in the reactor, and the furnace temperature. In general, if the growth rate is faster than the pyrolysis rate as described above, the carbon material grows in a fibrous form, while the pyrolysis rate is faster than the growth rate. The carbon material grows in the circumferential direction of the catalyst particles. Therefore, by intentionally changing the balance between the thermal decomposition rate and the growth rate, it is possible to form a three-dimensional structure in multiple directions under control without making the growth of the carbon material as described above constant. It is possible. In the intermediate to be produced, the composition of the catalyst, the residence time in the reaction furnace, the reaction temperature, and the gas temperature are used to easily form the three-dimensional structure as described above in which the fibers are bonded together by the granular material. Etc. are preferably optimized.

An intermediate obtained by heating and generating a mixed gas of catalyst and hydrocarbon at a constant temperature in the range of 800 to 1300 ° C. has a structure in which patch-like sheet pieces made of carbon atoms are bonded together, which will be described later. In the evaluation of graphitization degree by Raman spectroscopic analysis, it is found that the D band is very large and there are many defects. Moreover, the produced | generated intermediate body contains the unreacted raw material, non-fibrous carbon material, a tar content, and a catalyst metal.

Therefore, in order to remove these residues from such an intermediate and obtain a carbon nanotube structure with few defects, high-temperature heat treatment at 1500 to 3000 ° C. is performed by an appropriate method.

That is, for example, this intermediate is further heated at 800 to 1300 ° C. to remove volatile components such as unreacted raw materials and tars, and then annealed at a high temperature of 1500 to 3000 ° C. to obtain the desired structure. At the same time, the catalyst metal contained in the fibers is removed by evaporation. At this time, in order to protect the substance structure, a reducing gas or a small amount of carbon monoxide gas may be added to the inert gas atmosphere.

When the intermediate is annealed at a temperature in the range of 1500 to 3000 ° C., the patch-like sheet pieces made of carbon atoms are bonded to each other to form a plurality of graphene sheet-like layers.

Therefore, the granular part, which is a connecting part of the plurality of fine carbon fibers, and the fine carbon fiber share a multilayer graphene sheet, and the fine carbon fibers are firmly bonded to each other. And the outer diameter of the said granular part is 1.3 times or more of the average fiber outer diameter of a fine carbon fiber.

When producing the heating element, it is preferable to use carbon nanotubes having a tar content of 0.5% or less. When carbon nanotubes with few impurities such as tar are used when a heating element is manufactured or heated, emission of volatile organic compounds (VOC) can be reduced, which is convenient in terms of health and environment. For that purpose, carbon nanotubes annealed under the above temperature conditions may be used.

Further, before or after such high-temperature heat treatment, a step of crushing the equivalent circle average diameter of the carbon nanotube structure to several centimeters, and a circle equivalent average diameter of the cleaved carbon nanotube structure of 50 to By passing through a step of pulverizing to 100 μm, carbon nanotubes having a desired circle equivalent average diameter can be produced.

As a method for evaluating the graphitization degree of a carbon material, there is a method of measuring an R value using a Raman spectroscopic analyzer. Therefore, the carbon nanotube, which is a fine carbon material, also uses the R value measured and calculated by Raman spectroscopic analysis as an index of the degree of graphitization.

In Raman spectroscopic analysis, large single crystal graphite has no disorder in the graphene structure, so that only G band (IG, 1580 cm-1) appears at 1500-1600 cm-1. However, when the crystal has a finite minute size and the graphene structure has a defect, a D band (ID, 1360 cm-1) appears at 1250 to 1400 cm-1.

The R value is the intensity ratio (ID / IG) of the D band of 1250 to 1400 cm −1 due to this disorder of the graphite structure and the G band appearing at 1500 to 1600 cm −1 due to the graphene structure.

Therefore, when the R value of the carbon nanotube is small, the degree of graphitization is high and the graphene structure is less disturbed. On the other hand, when the R value of the carbon nanotube is large, the degree of graphitization is low, indicating that the graphene structure is largely disturbed.

When the R value of the carbon nanotube is small, the degree of graphitization is high and the graphene structure is less disturbed, so that the powder resistivity (Ω · cm) is low. In contrast, when the R value of the carbon nanotube is large, the degree of graphitization is low and the graphene structure is largely disturbed, so that the powder resistivity (Ω · cm) is high.

When composite materials are produced using carbon nanotubes with low powder resistivity (Ω · cm), composite materials are produced using carbon nanotubes with high powder resistivity (Ω · cm) in the same dispersion state. Compared to the case, the volume resistivity (Ω · cm) of the composite material is low.

Although the heating mechanism of the heating element of the present invention has not been clarified, it has been confirmed that the lower the resistance value between the electrodes of the heating element, the higher the heating characteristics at a low voltage. Accordingly, the interelectrode resistance value is preferably 105 Ω / cm or less, and more preferably 103 Ω / cm or less. Therefore, the R value of the carbon nanotube used in the present invention is preferably 1.0 or less, more preferably 0.7 or less, and further preferably 0.2 or less.

In the present invention, measurement was performed using a Raman spectroscopic analyzer LabRamHR-800 manufactured by Horiba Joban Yvon Co., Ltd., using an argon ion laser (514 nm), a laser spot diameter of 2 to 3 μm, and an excitation wavelength of laser power of 2 mW.

The above manufacturing method is merely an example, and various conditions such as the type of metal and the type of gas may be changed. Moreover, you may use the multi-layered carbon nanotube produced by production methods other than a vapor phase growth method.

The addition amount of the fine carbon fiber in the heating element of the present invention is in the range of 0.1 to 30 parts by mass, preferably 1 to 25 parts by mass, and more preferably 2 to 20 parts by mass. Thus, when there are few fine carbon fibers than 0.1 mass part, desired electroconductivity is difficult to be obtained. In addition, when the fine carbon fiber is 30 parts by mass or more, the fine carbon fiber is bulky, resulting in poor dispersion.

In the present invention, it is added by changing the type and addition amount of the dispersant for fine carbon fibers used depending on the type of resin and the type of organic solvent. About the dispersing agent for fine carbon fibers, you may use it combining several types.

Among the dispersants for fine carbon fibers used in the present invention, specific examples of the polymeric dispersant are shown in FIG. 1 and Table 1 below, but are not limited thereto.

The average degree of polymerization of the dispersant for fine carbon fibers of the present invention is in the range of 200 to 8000, preferably 300 to 5000, and particularly preferably 400 to 3000. Thus, when the average degree of polymerization of the dispersant for fine carbon fibers is less than 200, the desired performance cannot be obtained, and when the average degree of polymerization of the dispersant for fine carbon fibers is 8000 or more, it is used. Since the compatibility with the resin is lowered, the characteristics may be lowered.

About the composition ratio (X: Y: Z) of the dispersing agent for fine carbon fibers of this invention, the range of 65-90: 5-30: 0-10 is employable, Preferably it is 70-85: 10-25: 0. It is -8, Most preferably, it is 75-85: 15-20: 1-5. Thus, when the composition ratio of X is less than 65 in the dispersant for fine carbon fibers, the dispersion and defibration performance of the dispersant for fine carbon fibers cannot be obtained, and the composition ratio of X in the dispersant for fine carbon fibers is In the case of 90 or more, the compatibility with the resin being used is lowered, so that the characteristics may be lowered.

About the addition amount of the dispersing agent for fine carbon fibers of this invention, it is the range of 0.0005-100 mass parts with respect to 100 mass parts of fine carbon fibers, Preferably it is 0.015-100 mass parts, Especially preferably. Is 0.025 to 100 parts by mass. Thus, when there are few dispersing agents for fine carbon fibers than 0.0005 mass part, desired performance cannot be obtained. Moreover, when the dispersing agent for fine carbon fibers is 100 parts by mass or more, the characteristics of the resin used may be deteriorated.

Additives may be added to the conductive paint of the present invention according to other applications. For example, inorganic pigments, organic pigments, fillers, whiskers, thickeners, anti-settling agents, UV inhibitors, wetting agents, emulsifiers, anti-skinning agents, polymerization inhibitors, anti-sagging agents, antifoaming agents, color separation prevention Agent, leveling agent, drying agent, curing agent, curing accelerator, plasticizer, fireproofing / preventing agent, fungicide / algaeproofing agent, antibacterial agent, insecticide, marine antifouling agent, metal surface treatment agent, derusting agent, Examples include degreasing agents, film forming agents, bleaching agents, colorants, wood sealers, sealants, sanding sealers, sealers, cement fillers, and resin-containing cement pastes.

As a disperser that mixes and disperses fine carbon fibers in a resin material, a general disperser is used. For example, bead mill (Dynomill, Shinmaru Enterprise Co., Ltd.) TK Lab Disper, TK Philmix, TK Pipeline Mixer, TK Homomic Line Mill, TK Homo Jetter, TK Unimixer, TK Homomic Line Flow, TK Aji Homo Disper (Special Machine Industry Co., Ltd.), Homogenizer Polytron (Central Science Trade Co., Ltd.), Homogenizer Histron (Nippon Medical Science Equipment Co., Ltd.), Biomixer (Nippon Seiki Seisakusho Co., Ltd.), Turbo-type stirrer (Kodaira Manufacturing Co., Ltd.), Ultra Disper (Asada Steel Co., Ltd.), Ebara Mileser (Ebara Manufacturing Co., Ltd.), Ultrasonic Device or Ultrasonic Cleaning Machine (As One Co., Ltd.), OB Mill ( Turbo Industry Co., Ltd.), Micros (Nara Machinery Co., Ltd.), Three Roll Mill ( Yura - Corporation) and the like.

The heating element of the present invention is preferably manufactured through the order of the molding, curing or coating process, the heating layer forming process, the electrode forming process, and the insulating layer forming process. Or when the insulating base material in which the electrode was previously formed is used, it can manufacture through the order of a shaping | molding, hardening or application | coating process, a heat generating layer forming process, and an insulating layer forming process. Furthermore, when forming an electrode in the heat generating layer, a heating element is manufactured through steps such as a molding, curing or coating process, a heat generating layer forming process, an electrode forming process, a coating process, a heat generating layer forming process, and an insulating layer forming process. May be. Therefore, in manufacturing the heating element of the present invention, an electrode can be directly disposed on an insulating plate, and a conductive layer can be formed on or around the electrode. Therefore, it is possible to easily control the distance between the electrodes and heat generation.

As a method of coating the fine carbon fiber and the resin material of the present invention, general coating methods are listed below, but are not particularly limited thereto. Examples thereof include a dropping method, a dipping method, a screen printing method, an air spray coating, an airless spray coating, a low pressure atomizing spray coating, a coating by a bar coater method, and a coating using a spin coater.

The heating element forming step is a drying step after the fine carbon fiber and the resin material are coated on the substrate by the above method, and the coating film can be dried at room temperature. However, in order to sufficiently dry the coating film, the drying temperature is preferably heated to 10 to 500 ° C, more preferably 50 to 250 ° C, and particularly preferably 70 to 100 ° C. If the drying temperature is less than 10 ° C, the drying may not proceed sufficiently. If the drying temperature exceeds 500 ° C, the substrate may be deformed depending on the material. The drying time may be appropriately selected depending on the area of the planar heating layer and the drying temperature. The heating element forming step is not necessary except when the resin material is dissolved in water or an organic solvent to form a paint.

In the electrode forming step, a general electrode material can be used to form the insulating base material, in the planar heating layer, and on the planar heating layer. In the insulating layer forming process, a general forming process can be used.

Regarding the base material of the heating element, paper, film, rubber, glass, glass fiber, ceramic, gypsum, thermoplastic resin and thermosetting resin exhibiting heat resistance of 100 ° C. or higher, wood, or the like can be used.

The heating element may have a flat or curved structure, or may be installed on a flexible material.

By coating the heat generating layer, the life of the heat generating element can be extended. Further, it is possible to prevent the fine carbon fibers from peeling off. As for the power source, either an alternating voltage (AC) or a direct voltage (DC) may be used.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

The method of synthesizing fine carbon fibers having an average diameter of 70 nm and an R value of 0.1 uses a CVD method to evaporate a mixed liquid of hydrocarbon and catalyst as raw materials and use hydrogen gas or the like as a carrier gas in the reaction furnace. It was introduced and thermally decomposed at a temperature of 1250 ° C. to synthesize an intermediate. The obtained intermediate is heated at 1200 ° C. to remove volatile components such as unreacted raw materials and tars, and then annealed at 2500 ° C., whereby an average diameter of 70 nm and an R value of 0.1 are obtained. Carbon fiber was obtained.

The intermediate obtained in Example 1 was heated at 1200 ° C. to remove volatile components such as unreacted raw materials and tars, and then annealed at 1800 ° C. to obtain an average diameter of 70 nm and an R value of 0. A fine carbon fiber of .7 was obtained.

The intermediate obtained in Example 1 was annealed at 1200 ° C. to obtain fine carbon fibers having an average diameter of 70 nm and an R value of 1.0.

The fine carbon fiber-containing resin solution was prepared by dissolving 53 g of AS resin (acrylonitrile-styrene copolymer resin, Sebian N-70, manufactured by Daicel Polymer Co., Ltd.) in a mixed solvent of 224 g of toluene and 224 g of 2-butanone. 501 g of a 0.6 mass% AS resin solution was prepared.

5.94 g of fine carbon fibers having an average diameter of 70 nm and an R value of 0.1 synthesized in Example 1 were added to 501 g of the prepared AS resin solution, and the dispersant for fine carbon fibers shown in Table 1 (Compound 2) 0.594 g was added and dispersed and defibrated using a bead mill disperser (Dynomill manufactured by Shinmaru Enterprise Co., Ltd.) to prepare a fine carbon fiber-containing AS resin solution in which fine carbon fibers were uniformly dispersed and defibrated. did.

A heating element is prepared by using a fine carbon fiber-containing AS resin solution, a coated paper is prepared by a bar coater method on cardboard cut to a width of 50 mm and a length of 50 mm, and dried by a hot air machine for 30 minutes. A heat generating layer was produced. The obtained heat generating layer had a width of 40 mm, a length of 40 mm, and a thickness of 24 μm, and electrodes were made of silver paste on both ends of the heat generating layer.

For the evaluation of the voltage-surface temperature characteristics of the heating element, the interelectrode resistance value is measured using a DIGITAL MULTITIMER (CUSTOM, CDM-17D), and the surface temperature of the heating element is measured by a radiation thermometer (TASCO, THI- 44NH). The evaluation of the heat generation characteristics of the heating element was performed by changing the applied voltage to the voltage shown in Tables 1 to 3 using a variable voltage regulator (YAMABISHI ELECTRIC CO., LTD. S-130-10), and 10 minutes passed after the voltage change. The surface temperature at the time and the surface temperature of the central portion of the heating element were measured using a radiation thermometer. The surface temperature was measured in a constant temperature and humidity chamber (room temperature 23 ° C., humidity 27%). These results are shown in Table 2.

A heating element was produced according to Example 4 except that the fine carbon fiber having an average diameter of 70 nm and an R value of 1.0 obtained in Example 3 was used. The conductive film had a width of 40 mm, a length of 40 mm, and a thickness of 14 μm. The exothermic characteristic results are shown in Table 2.

A heating element was produced in the same manner as in Example 4 except that the heating layer had a width of 40 mm, a length of 80 mm, and a thickness of 22 μm. The exothermic characteristic results are shown in Table 2.

A heating element was produced according to Example 4 except that the fine carbon fiber having an average diameter of 70 nm and an R value of 1.0 obtained in Example 3 was used. The conductive film had a width of 40 mm, a length of 80 mm, and a thickness of 21 μm. The exothermic characteristic results are shown in Table 2.

A heating element was produced in the same manner as in Example 4 except that the heating layer had a width of 40 mm, a length of 120 mm, and a thickness of 25 μm. The exothermic characteristic results are shown in Table 2.

A heating element was produced according to Example 4 except that the fine carbon fiber having an average diameter of 70 nm and an R value of 1.0 obtained in Example 3 was used. The conductive film had a width of 40 mm, a length of 120 mm, and a thickness of 19 μm. The exothermic characteristic results are shown in Table 2.

A heating element was produced in the same manner as in Example 4 except that the heating layer was 100 mm wide, 100 mm long and 24 μm thick. The exothermic characteristic results are shown in Table 2.

A heating element was prepared in the same manner as in Example 4 except that a glass substrate (Matsunami Co., Ltd. 50 × 150 × 1.65 mm) was used as a base material and a heating layer having a width of 40 mm, a length of 40 mm and a thickness of 41 μm was formed thereon. Produced. The exothermic characteristic results are shown in Table 2.

A heating element was produced in the same manner as in Example 4 except that a natural rubber substrate (40 × 40 × 3 mm) was used as a base material and a heating layer having a width of 40 mm, a length of 40 mm and a thickness of 17 μm was formed thereon. The exothermic characteristic results are shown in Table 2.

Implementation was performed except that an alumina substrate (Irie Co., Ltd. SSA-T square plate / 50 × 50 × 0.5 mm) was used as the base material, and a heating layer having a width of 40 mm, a length of 40 mm, and a thickness of 27 μm was formed thereon. A heating element was produced in the same manner as in Example 4. The exothermic characteristic results are shown in Table 2.

A heating element was prepared in the same manner as in Example 4 except that a glass substrate (Matsunami Co., Ltd. 50 × 150 × 1.65 mm) was used as a base material and a heating layer having a width of 40 mm, a length of 80 mm and a thickness of 34 μm was formed thereon. Produced. The exothermic characteristic results are shown in Table 2.

A heating element was prepared in the same manner as in Example 4 except that a glass substrate (Matsunami Co., Ltd. 50 × 150 × 1.65 mm) was used as a base material, and a heating layer having a width of 40 mm, a length of 120 mm, and a thickness of 26 μm was formed thereon. Produced. The exothermic characteristic results are shown in Table 2.

The fine carbon fiber-containing elastomer solution was prepared by dissolving 5 g of EPDM unvulcanized resin (manufactured by Co., Ltd.) in 95 g of toluene to prepare 100 g of a 5 mass% EPDM resin solution.

0.56 g of fine carbon fiber having an average diameter of 70 nm and an R value of 0.1 of Example 1 is put into 100 g of the prepared EPDM unvulcanized solution, and a bead mill disperser (Dynomill manufactured by Shinmaru Enterprise Co., Ltd.) is used. Dispersion and defibration treatment were performed to prepare an EPDM unvulcanized solution containing fine carbon fibers.

A heating element was prepared by applying a coating film by a bar coater method on a glass substrate (Matsunami Co., Ltd. 50 × 150 × 1.65 mm) cut to a width of 50 mm and a length of 50 mm using a fine carbon fiber-containing EPDM unvulcanized solution. It produced and dried with the warm air machine for 30 minutes, and produced the heat generating layer. The obtained heat generating layer had a width of 40 mm, a length of 40 mm, and a thickness of 40 μm, and an electrode was made of silver paste on both ends of the heat generating layer. The exothermic characteristic results are shown in Table 2.

It was produced according to Example 16 except that fine carbon fibers having an average diameter of 70 nm and an R value of 0.7 of Example 2 were used. The conductive film had a width of 40 mm, a length of 40 mm, and a thickness of 39 μm. The exothermic characteristic results are shown in Table 2.

Except that the fine carbon fiber-containing EPDM unvulcanized solution of Example 16 was used to produce a heating layer having a width of 40 mm, a length of 80 mm, and a thickness of 36 μm. The exothermic characteristic results are shown in Table 2.

It was produced according to Example 16 except that fine carbon fibers having an average diameter of 70 nm and an R value of 0.7 of Example 2 were used. The conductive film had a width of 40 mm, a length of 80 mm, and a thickness of 43 μm. The exothermic characteristic results are shown in Table 2.

Except that the fine carbon fiber-containing EPDM unvulcanized solution of Example 16 was used to produce a heating layer having a width of 40 mm, a length of 120 mm, and a thickness of 34 μm. The exothermic characteristic results are shown in Table 2.

It was produced according to Example 16 except that fine carbon fibers having an average diameter of 70 nm and an R value of 0.7 of Example 2 were used. The conductive film had a width of 40 mm, a length of 120 mm, and a thickness of 38 μm. The exothermic characteristic results are shown in Table 2.

0.7 g of fine carbon fibers having an average diameter of 70 nm and an R value of 0.1 of Example 1 are put into 100 g of the prepared EPDM unvulcanized solution, and a bead mill disperser (Dynomill manufactured by Shinmaru Enterprise Co., Ltd.) is used. Dispersion and defibration treatment were performed to prepare an EPDM unvulcanized solution containing fine carbon fibers.

A heating element was prepared by using a fine carbon fiber-containing EPDM unvulcanized solution, a coating film was prepared by screen printing on an EPDM vulcanized rubber that had been cut to a width of 150 mm and a length of 220 mm. It dried for 30 minutes and produced the heat generating layer. The obtained heat generating layer had a width of 120 mm, a length of 200 mm and a thickness of 42 μm, and the electrode was obtained by bonding a copper plate to both ends of the heat generating layer. An unvulcanized rubber was placed on these, a heat generating layer was sandwiched between them, and a heat generating body in which the heat generating element was sandwiched was prepared by vulcanization treatment. The heat generation characteristics were evaluated based on the usage environment at 100 V AC, and the results are shown in Table 2.

The fine carbon fiber-containing polyamic acid solution was prepared by adding 60 g of a polyamic acid solution (U-Varnish-A, manufactured by Ube Industries Co., Ltd.) to a fine carbon having an average diameter of 70 nm and an R value of 0.1. 1.62 g of fibers were added, and a dispersion and defibrating treatment was performed using a three-roll mill disperser (BRL-150V manufactured by IMEX Co., Ltd.) to prepare a fine carbon fiber-containing polyamic acid solution.

The heating element was prepared by using a fine carbon fiber-containing polyamic solution to form a coating film on a heat-resistant polyimide film cut to a width of 20 mm and a length of 250 mm by the bar coater method. Drying and curing were performed at 10 ° C./10 minutes, 250 ° C./10 minutes, and 350 ° C./10 minutes to prepare a heat generating layer of the fine carbon fiber-containing polyimide resin. The obtained heat generating layer had a width of 5 mm, a length of 220 mm, and a thickness of 35 μm, and electrodes were made of silver paste on both ends of the heat generating layer. The exothermic characteristic results are shown in Table 2.

Using the fine carbon fiber-containing polyamic solution of Example 23, a coating film was prepared by a bar coater method on a heat-resistant polyimide film cut to a width of 210 mm and a length of 300 mm, and 120 ° C./30 minutes, 200 ° C./10. Minute, 250 degreeC / 10 minutes, and 350 degreeC / 10 minutes were dried and hardened, and the heat_generation | fever layer of the fine carbon fiber containing polyimide resin was produced. The obtained heat generating layer had a width of 204 mm, a length of 290 mm, and a thickness of 45 μm, and an electrode was made of silver paste on both ends of the heat generating layer. The exothermic characteristic results are shown in Table 2.

An epoxy resin [Adeka Resin EP-4100E manufactured by Asahi Denka Kogyo Co., Ltd.] 100 g and a curing agent [Adeka Hardener EH-3636AS manufactured by Asahi Denka Kogyo Co., Ltd.] 8 g have an average diameter of 70 nm and an R value of 0.00. 2% by mass of the fine carbon fiber 1 was mixed and dispersed with a disperser [THINKY CORPORATION Foaming Nertaro AR-250]. The obtained fine carbon fiber-containing epoxy resin-curing agent mixed solution is coated on a glass substrate (Matsunami Co., Ltd. 50 × 150 × 1.65 mm) by a bar coater method and cured from room temperature to 180 ° C. over 1 hour. It was. The obtained heat generating layer had a width of 50 mm, a length of 80 mm, and a thickness of 200 μm, and electrodes were made of silver paste on both ends of the heat generating layer. The exothermic characteristic results are shown in Table 2.

Exothermic heat was generated in the same manner as in Example 25 except that fine carbon fibers having an average diameter of 70 nm and an R value of 0.1 of Example 1 were used, and a width of 50 mm, a length of 80 mm, and a thickness of 231 μm were produced on a glass substrate. The body was made. The exothermic characteristic results are shown in Table 2.

Preparation of fine carbon fiber-containing screen printing ink (SS800 medium manufactured by Toyo Ink Co., Ltd.) was put in 900 g, 100 g of fine carbon fiber having an average diameter of 70 nm and an R value of 0.1 in Example 1, and a three-roll mill. Dispersion and fibrillation treatment was performed using a disperser (Bureler Co., Ltd. SDX300-CLC) to prepare a screen printing ink containing fine carbon fibers.

The heating element was prepared by printing twice on a polycarbonate film cut to a width of 60 mm and a length of 660 mm using a fine carbon fiber-containing screen printing ink by a screen printing method using a printing plate T-100. A coating film was prepared to produce a heat generating layer of the fine carbon fiber-containing screen printing ink. The obtained heat generating layer had a width of 50 mm, a length of 600 mm, and a thickness of 29 μm, and electrodes were made of silver paste at both ends of the heat generating layer. The exothermic characteristic results are shown in Table 2.

A coating film was prepared by a screen printing method using the printing plate T-80, and further a screen coating method using the printing plate T-100 was further printed thereon to produce a coating film. A heating element was produced in the same manner as in Example 27. The obtained heat generating layer had a width of 50 mm, a length of 600 mm, and a thickness of 45 μm, and electrodes were made of silver paste on both ends of the heat generating layer. The exothermic characteristic results are shown in Table 2.

[Comparative example]
Exothermic heat was generated in the same manner as in Example 25 except that fine carbon fibers having an average diameter of 70 nm and an R value of 1.0 of Example 3 were used, and a width of 50 mm, a length of 80 mm, and a thickness of 200 μm were produced on a glass substrate. The body was made. The exothermic characteristics results are shown in Table 2.

When a thermoplastic resin, a thermosetting resin, an elastomer material, and a printing ink are used as the resin material, an example in which the interelectrode resistance value (Ω / cm) of the present invention is 105 or less is the interelectrode resistance value (Ω It is clear that the surface temperature is higher at a lower voltage than the comparative example in which / cm) is 105 or more. It is also clear that this phenomenon appears more prominently as the interelectrode distance increases.

Further, it is apparent that the base material used in the present invention can be coated on the substrate using paper, film, rubber, glass, ceramic, thermoplastic resin or thermosetting resin to form a heat generating layer.

By using the fine carbon fiber and the resin material of the present invention, a heating element having a resistance value between electrodes (Ω / cm) of 105 or less can easily produce a heating element exhibiting a high heating temperature at a low voltage. Therefore, it can be used as a heating element driven by a generator, a battery, a dry cell or the like not only indoors with an AC 100 V power source but also outdoors (eg, a disaster area) without an AC 100 V power source. It can also be used in automobiles. As the heat generation temperature, electric carpets that require a heat generation temperature of 100 ° C. or less, floor heating, wall heating equipment, heating equipment for livestock, snow melting materials used for roads, roofs, entrances, etc., pipeline freeze prevention heaters, etc. It can be used as a heat source. Further, it can be used as a heating element used in a manufacturing process or the like that requires an exothermic temperature of 100 to 200 ° C. Further, it can be used for a heat generating heater, a heat fixing roller and a belt for a fixing portion of a copying machine and a laser printer that require a heat generating temperature of 200 ° C. or more.

Claims (26)

A heating element comprising a fine carbon fiber and a resin material and having an interelectrode resistance value (Ω / cm) of 10 ⁵ or less. 2. The heating element according to claim 1, wherein the fine carbon fiber has an R value of 1.0 or less by Raman spectroscopic analysis. The heating element according to claim 2, wherein the fine carbon fiber has an R value of 0.7 or less by Raman spectroscopic analysis. The heating element according to claim 3, wherein the fine carbon fiber has an R value of 0.2 or less by Raman spectroscopic analysis. The heating element according to claim 1, wherein the resin material is a thermoplastic resin. The heating element according to claim 1, wherein the resin material is a thermosetting resin. The heating element according to claim 1, wherein the resin material is an elastomer material. The heating element according to any one of claims 1 to 4, wherein the resin material is a printing ink. The heating element according to any one of claims 1 to 8, wherein the heating element is obtained by molding, curing, or applying the resin material containing the fine carbon fibers to a base material. The heating element according to any one of claims 1 to 9, wherein a dispersant for fine carbon fibers is added to the resin material containing the fine carbon fibers. The heating element according to claim 10, wherein the dispersant for fine carbon fibers contains at least one polymer dispersant. The heating element according to claim 11, wherein the polymer dispersant is a polyvinyl butyral resin. The heating element according to claim 11 or 12, wherein the polymer dispersant is 0.0005 to 100 parts by mass with respect to 100 parts by mass of fine carbon fibers. The heating element according to claim 9, wherein the base material is a material selected from the group of paper, rubber, glass, glass fiber, ceramic, gypsum, a thermoplastic resin, or a thermosetting resin. The heating element according to claim 1, wherein 0.1 to 30 parts by mass of fine carbon fiber is added to 100 parts by mass of the resin material. The heating element according to any one of claims 1 to 15, wherein the fine carbon fiber is composed of fine carbon fibers having an average outer diameter of 10 to 300 nm. The heating element according to any one of claims 1 to 16, wherein the fine carbon fiber has a single-layer structure, a double-layer structure, or a multilayer structure. The fine carbon fiber is a three-dimensional network-like fine carbon fiber structure composed of fine carbon fibers having an average outer diameter of 10 to 300 nm, and the fine carbon fiber structure has a plurality of granular parts, In a mode in which the plurality of fine carbon fibers extend with a three-dimensional extension from the granular part, the fine carbon fiber is at least partially formed by a mode in which the extending fine carbon fiber is also bonded to other granular parts. The heating element according to claim 1, wherein the heating element has a three-dimensional network structure. By using at least two or more carbon compounds having a particle diameter larger than the outer diameter of the fine carbon fiber and having different decomposition temperatures as carbon sources, The exothermic heat according to any one of claims 1 to 18, wherein the substance is formed in a growth process in which the substance is grown in the form of fibers while growing in the circumferential direction of the catalyst particles used. body. The heating element according to any one of claims 1 to 19, wherein the fine carbon fibers are composed of fine carbon fibers having an average outer diameter of 15 to 100 nm. The heating element according to any one of claims 1 to 20, wherein the fine carbon fiber is a high-purity fine carbon fiber having a tar content of 0.5% or less. The film-shaped heating element according to any one of claims 1 to 21, wherein the heating layer of the heating element has a thickness of 0.3 mm or less. The heating element according to any one of claims 1 to 22, wherein electrodes are provided at both ends of the heating layer of the heating element. A method of manufacturing a heating element, comprising: a step of applying a resin material containing the fine carbon fiber to a substrate to manufacture a heating layer; and a step of curing or drying the applied heating layer. The method for manufacturing a heating element according to claim 24, further comprising a step of forming an electrode on the heating layer. 26. The method of manufacturing a heating element according to claim 25, further comprising an insulating layer forming step of covering the heating layer and the electrode with a resin material.