WO2004023845A1 - Seat-like heating units using carbon nanotubes - Google Patents

Seat-like heating units using carbon nanotubes Download PDF

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Publication number
WO2004023845A1
WO2004023845A1 PCT/KR2002/001466 KR0201466W WO2004023845A1 WO 2004023845 A1 WO2004023845 A1 WO 2004023845A1 KR 0201466 W KR0201466 W KR 0201466W WO 2004023845 A1 WO2004023845 A1 WO 2004023845A1
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WO
WIPO (PCT)
Prior art keywords
carbon nanotubes
sheet
heating unit
matrix
shaped heating
Prior art date
Application number
PCT/KR2002/001466
Other languages
French (fr)
Inventor
Taek Soo Lee
Young Soo Park
Original Assignee
Nanotech Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nanotech Co., Ltd. filed Critical Nanotech Co., Ltd.
Priority to AU2002313956A priority Critical patent/AU2002313956A1/en
Priority to PCT/KR2002/001466 priority patent/WO2004023845A1/en
Publication of WO2004023845A1 publication Critical patent/WO2004023845A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y10/00—Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/10—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/12—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
    • H05B3/14—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material the material being non-metallic
    • H05B3/145—Carbon only, e.g. carbon black, graphite
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/20—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater
    • H05B3/22—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible
    • H05B3/26—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible heating conductor mounted on insulating base
    • H05B3/265—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible heating conductor mounted on insulating base the insulating base being an inorganic material, e.g. ceramic
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/20—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater
    • H05B3/22—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible
    • H05B3/26—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible heating conductor mounted on insulating base
    • H05B3/267—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible heating conductor mounted on insulating base the insulating base being an organic material, e.g. plastic
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2214/00—Aspects relating to resistive heating, induction heating and heating using microwaves, covered by groups H05B3/00, H05B6/00
    • H05B2214/04—Heating means manufactured by using nanotechnology

Definitions

  • the present invention relates to a sheet-shaped heating unit containing carbon nanotubes and a method of preparing the same, and more specifically, to a sheet-shaped heating unit wherein a specific amount of nanotubes is dispersed in a matrix such as a polymer material or ceramic material, the carbon nanotubes being in electrical contact with one another, thereby exhibiting an excellent heating rate efficiency and also being able to be molded into various structures, and a method of preparing the same.
  • sheet-shaped heating units have a configuration wherein a nichrome wire as a heating member, which is coated with an insulating material, is continuously arranged in the groove of a sheet in a bended form and electrodes are connected to each end of the nichrome wire.
  • the sheet-shaped heating unit of this configuration has a demerit that the insulating coat may be peeled or melted by heat of a very high temperature conducted from the nichrome wire being excessively heated in some cases.
  • a ceramic material is sometimes used as the insulating coat which, however, increases the weight of the sheet-shaped heating unit and also makes the bending shape difficult to achieve the bending shape of the nichrome wire.
  • a carbon-based heating unit prepared by a method wherein carbon blacks
  • an object of the present invention is to solve the aforementioned problems and at the same time meet the requirements in the prior art. That is, an object of the present invention is to provide a sheet-shaped heating unit which has good moldability and excellent uniformity of heat radiation and in which a small amount of nanotubes with good electrical- and heat-conductivity are dispersed in a matrix under a specific condition. Another object of the present invention is to provide a method of preparing the above sheet-shaped heating unit.
  • the present invention provides a sheet-shaped heating unit in which isotropic carbon nanotubes of the length of several ⁇ m ⁇ hundreds of ⁇ m are dispersed in an electrically insulating matrix in the amount of 0.5 ⁇ 50% by weight based upon the total weight of a heating complex, the carbon nanotubes being in electrical contact with one another.
  • the term heating complex means an element including the carbon nanotubes and the matrix and performing heat radiation when current is applied thereto.
  • the very fine carbon nanotubes are dispersed in the insulating matrix under the specific condition that the carbon nanotubes are in electrical contact with one another, whereby the sheet-shaped heating unit can exhibit a higher heat- radiation rate efficiency than the prior art heating unit even by addition of a relatively small amount of carbon nanotubes, and can also be easily molded into various structures. Furthermore, since the carbon nanotubes also act as a reinforcing agent, the mechanical properties such as the bending strength of the sheet-shaped heating unit are improved.
  • the prior art sheet-shaped heating unit in which conductive carbon particles are dispersed in a polymer matrix achieves a desired resistance for heating only when a large amount of carbon particles are contained in the heating unit, resulting in the difficulty of molding and the deterioration of mechanical properties.
  • the sheet-shaped heating unit according to the present invention exhibits electrical conductivity comparable to that of the prior art sheet- shaped heating unit by dispersing only a small amount of carbon nanotubes in a matrix under a specific condition, and also does not suffer deterioration of its mechanical properties, while having moldability and pliability owing to the use of a small amount of additives, i.e., carbon nanotubes.
  • Carbon nanotubes used in the sheet-shaped heating unit of the present invention generally have the characteristic properties as described below.
  • the carbon nanotube as seen in FIG. 1, has a diameter of 1 ⁇ 500 nm and a length of several ⁇ m ⁇ hundreds of ⁇ m and thus has a high isotropy in view of configuration. Moreover, the carbon nanotube has a conductivity of -lO ⁇ , which means that the carbon nanotube is a conductor.
  • the carbon nanotube is mechanically rigid (approximately 100 times more rigid than steel) and chemically stable and also has excellent thermal conductivity of 2000 W/mK.
  • the carbon nanotube is hollow and thus has a lower density compared to graphite or carbon fibers as general carbon materials.
  • the carbon nanotube has a large L/R (length/radius) ratio of 100 ⁇ 10,000 and can act as a conductor in series with other carbon nanotubes when a current is fed thereto. Accordingly, even when a small amount of carbon nanotubes is used, the resulting heating unit can exhibit similar electrical conductivity to other heating units containing a large amount of different carbon materials.
  • a multilayered wall carbon nanotube as well as a single- layered wall carbon nanotube can be adapted for the carbon nanotube in the present invention.
  • the addition amount of carbon nanotubes is, as mentioned above, 0.5 ⁇ 50% by weight, preferably 1 ⁇ 30% by weight, more preferably 3 ⁇ 20% by weight on the basis of the total weight of a heating complex, the heating complex comprising carbon nanotubes and a matrix. So long as the electrical connection of carbon nanotubes to one another can be achieved, a smaller amount of carbon nanotubes may be used in order to accomplish the object of the present invention.
  • electrical contact means the condition wherein a carbon nanotube is in physical contact with other carbon nanotubes to conduct electricity therebetween. This term simultaneously means the condition wherein a carbon nanotube is spaced apart from other carbon nanotubes but the distance therebetween is in the range allowing electron tunneling to occur.
  • FIG. 2 there is illustrated an example wherein a plurality of carbon nanotubes 210 are dispersed in an electric insulating matrix 220, while being in electrical contact with one another.
  • a matrix used in the present invention is not particularly limited so long as it is a material which is thermo-conductive and thermo-stable and in which fine carbon nanotubes can be dispersed under a specific condition that the carbon nanotubes are in electrical contact with one another.
  • a material includes, for example, but is not limited to polymer materials meeting the above requirements, and ceramic materials.
  • polymer material examples include, but are not limited to polyethylene (PE), polypropylene (PP), polystyrene (PS), polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinylchloride (PVC), phenol resins, urea resins, melamine resins, polyester resins, epoxy resins, diarylphthalate resins, polyurethane resins, silicone resins, etc.
  • the polyester resins are more preferable in consideration of easy moldablility and include, for example, but are limited to unsaturated polyester resins, alkyd resins, polyethylene terephthalate, and the like.
  • ceramic material examples include, but are not limited to alumina (Al 2 O 3 ), silica (SiO 2 ), zirconia (ZrO 2 ), etc.
  • an insulating material may be laminated to the outer surface of a heating complex comprising carbon nanotubes and a matrix so as to prevent electricity leakage resulting from exposure of the heating complex to the exterior.
  • FIGS. 3 and 4 there are illustrated sheet-shaped heating units in which electrodes are connected to a heating complex in an attachment manner, respectively.
  • a sheet-shaped heating unit 100 is configured such that two electrodes 300 are attached to both lateral surfaces of a planar heating complex 200 and two insulators 400 cover the upper and lower surfaces of the electrodes 300 and heating complex 200.
  • the heating complex 200 is not limited to a planar shape.
  • a sheet-shaped heating unit 101 may be configured such that two electrodes 201 are attached to both lateral surfaces of a heating complex 201 having a square cross-section.
  • FIGS. 5 and 6 there are shown sheet-shaped heating units in which electrodes are connected to a heating complex in the insertion manner or the attachment/insertion manner. More specifically, in the insertion manner, one or more pairs of electrodes are inserted into a planar heating complex. Meanwhile, in the attachment/insertion manner, some portions of electrodes which are attached to both lateral surfaces of a heating complex having a square cross-section are extended to the inside of the heating complex.
  • the sheet-shaped heating unit of the insertion manner or attachment/insertion manner is characterized by a higher heating efficiency than that of the sheet-shaped heating unit of the attachment manner.
  • a heating complex 202 in which the upper and lower surfaces are attached to insulators 402 is configured in the insertion manner, such that a plurality of electrodes 503 pass through the inside of the heating complex 202 but are not attached to the outer surfaces thereof. Therefore, the sheet-shaped heating unit 202 in FIG. 5 can produce a greater amount of radiant heat than the sheet-shaped heating unit 200 in FIG. 3.
  • a sheet-shaped heating unit 103 in FIG. 6 has a structure such that electrodes 301 as seen in FIG. 3 extend, in some portions thereof, to the inside of a heating complex 403 to form extended electrodes 503. These extended electrodes 503 are not in contact with one another and, preferably, are spaced apart from one another at a constant interval to ensure even heat radiation.
  • Electrodes as described above serve to induce the heating of a heating complex when current is applied thereto, and thus are not particularly limited so long as they are of a material having high conductivity.
  • a highly conductive material includes, for example, but is not limited to metal plates such as silver plate, copper plate, aluminum plate, etc. and conductive composite plates of polymer or ceramic material containing a large amount of conductive materials such as metal particles, carbon powders, carbon nanotubes, etc.
  • the sheet-shaped heating unit may include other elements or be configured in other structures.
  • the present invention also provides a method for preparing the aforementioned sheet- shaped heating unit.
  • a method for preparation of the sheet-shaped heating unit comprises the steps of,
  • the matrix is composed of a polymer material
  • a method whereby carbon nanotubes are mixed in liquid-phase monomers and then polymerized with the aid of a catalyst or a method whereby the polymer is dissolved in a solvent to provide a liquid solution and carbon nanotubes are mixed in the solution and then the solvent is removed, but the method is not limited thereto.
  • the matrix is of a ceramic material
  • Methods for mixing carbon nanotubes in a matrix are not particularly limited so long as the carbon nanotubes are dispersed in the matrix with the carbon nanotubes being electrically connected to one another.
  • mixing methods include, but are not limited to a mixing screw method, a shear mixer method, a melt blending method, etc.
  • the carbon nanotubes have a large L/R ratio, that is, a high anisotropy, the electrical connection thereof can be readily achieved when they are evenly dispersed.
  • the amount of carbon nanotubes used can be reduced in order to provide a sheet-shaped heating unit of the present invention.
  • the resistivity of the sheet-shaped heating unit prepared thus is in the range of approximately 1 ⁇ 10 5 ⁇ Cm.
  • FIG. 1 is an electron micrograph of carbon nanotubes useful for the sheet-shaped heating unit of the present invention
  • FIG. 2 is a schematic view of carbon nanotubes dispersed in a matrix, with the carbon nanotubes being electrically in contact with one another, in accordance with the present invention
  • FIGS. 3 and 4 are schematic views of the sheet-shaped heating units according to some embodiments of the present invention, wherein electrodes are connected to heating complexes in the attachment manner, respectively;
  • FIGS. 5 and 6 are schematic views of the sheet-shaped heating unit according to some embodiments of the present invention, wherein electrodes are connected to heating complexes in the attachment/insertion manner, respectively.
  • Carbon nanotubes were prepared by a conventional thermal decomposition method in which ferrocene as a metallic catalyst is dissolved in benzene as a carbon stock and the resulting solution is heated at high temperature of 1000°C in an electric furnace to synthesize carbon nanotubes.
  • a specimen was prepared in the same manner as in EXAMPLE 1 except for using 95 g of the polyester resin and 5 g of the carbon nanotubes and the resistivity of the specimen was measured. The results are described in TABLE 1 below.
  • a specimen was prepared in the same manner as in EXAMPLE 1 except for using 94 g of the polyester resin and 6 g of the carbon nanotubes and the resistivity of the specimen was measured. The results are described in TABLE 1 below.
  • a specimen was prepared in the same manner as in EXAMPLE 1 except for using 93 g of the polyester resin and 7 g of the carbon nanotubes and the resistivity of the specimen was measured. The results are described in TABLE 1 below.
  • a specimen was prepared in the same manner as in EXAMPLE 1 except for using 90 g of the polyester resin and 10 g of the carbon nanotubes and the resistivity of the specimen was measured. The results are described in TABLE 1 below.
  • a specimen was prepared in the same manner as in EXAMPLE 1 except for using 80 g of the polyester resin and 20 g of the carbon nanotubes and the resistivity of the specimen was measured. The results are described in TABLE 1 below.
  • a specimen was prepared in the same manner as in EXAMPLE 1 except for not using carbon nanotubes and the resistivity of the specimen was measured. The results are described in TABLE 1 below.
  • the sheet-shaped heating units prepared in EXAMPLES 1 ⁇ 6 according to the present invention have low resistivity of 1 ⁇ -cm ⁇ 10 6 ⁇ -cm meeting the requirement for a good heating unit, while the sheet-shaped heating unit prepared in the COMPARATIVE EXAMPLE containing no carbon nanotubes was ascertained to have resistivity beyond 200 M ⁇ -cm, the detection limit of the resistance meter, which indicates that the material is practically an insulator.
  • the sheet-shaped heating unit according to the present invention has a high electrical conductivity even when a small amount of carbon nanotubes are contained therein, and can be readily molded in various structures, and has good mechanical properties such as bending strength. Furthermore, the carbon nanotubes have a higher thermal conductivity at 1800 ⁇ 6000 W/mK than that of conventional materials, thus the sheet-shaped heating unit of the present invention containing them exhibits excellent conductive properties without addition of ceramic materials, resulting in the reduction of manufacturing cost thereof.

Abstract

The present invention provides a sheet-shaped heating unit comprising anisotropic carbon nanotubes of the length of several µm to hundreds of µm at an amount of 0.5 to 50% by weight on the basis of the total amount of a heating complex, the carbon nanotubes being in electrical contact with one another in an electrically insulating matrix, in which the heating complex comprises the carbon nanotubes and the matrix, and a method for preparation of the same. The sheet-shaped heating unit according to the present invention has a high electrical conductivity even when a small amount of carbon nanotubes is contained therein, and can be molded into various structures, and has good mechanical properties.

Description

SEAT-LIKE HEATING UNITS USING CARBON NANOTUBES
FIELD OF THE INVENTION
The present invention relates to a sheet-shaped heating unit containing carbon nanotubes and a method of preparing the same, and more specifically, to a sheet-shaped heating unit wherein a specific amount of nanotubes is dispersed in a matrix such as a polymer material or ceramic material, the carbon nanotubes being in electrical contact with one another, thereby exhibiting an excellent heating rate efficiency and also being able to be molded into various structures, and a method of preparing the same.
BACKGROUND OF THE INVENTION
In general, sheet-shaped heating units have a configuration wherein a nichrome wire as a heating member, which is coated with an insulating material, is continuously arranged in the groove of a sheet in a bended form and electrodes are connected to each end of the nichrome wire. However, the sheet-shaped heating unit of this configuration has a demerit that the insulating coat may be peeled or melted by heat of a very high temperature conducted from the nichrome wire being excessively heated in some cases.
In order to prevent this problem, a ceramic material is sometimes used as the insulating coat which, however, increases the weight of the sheet-shaped heating unit and also makes the bending shape difficult to achieve the bending shape of the nichrome wire.
Alternatively, a carbon-based heating unit, prepared by a method wherein carbon blacks
-ι- are mixed with a binder and the resulting mixture is molded in the shape of sheet, is often used as the sheet-shaped heating unit. However, in order for the carbon blacks to serve as a heating member, a large amount thereof must be mixed with the binder, thereby deteriorating the mechanical properties such as the bending strength and causing difficulty in molding the heating member.
Under Ibis current circumstances, there is a strong need for a sheet-shaped heating unit having a high heating rate efficiency and excellent mechanical properties and being capable of being easily molded.
SUMMARY OF THE INVENTION
Accordingly, the object of the present invention is to solve the aforementioned problems and at the same time meet the requirements in the prior art. That is, an object of the present invention is to provide a sheet-shaped heating unit which has good moldability and excellent uniformity of heat radiation and in which a small amount of nanotubes with good electrical- and heat-conductivity are dispersed in a matrix under a specific condition. Another object of the present invention is to provide a method of preparing the above sheet-shaped heating unit.
To accomplish the foregoing objects and advantages, the present invention provides a sheet-shaped heating unit in which isotropic carbon nanotubes of the length of several μm ~ hundreds of μm are dispersed in an electrically insulating matrix in the amount of 0.5 ~ 50% by weight based upon the total weight of a heating complex, the carbon nanotubes being in electrical contact with one another. As used herein, the term heating complex means an element including the carbon nanotubes and the matrix and performing heat radiation when current is applied thereto. In accordance with the present invention, the very fine carbon nanotubes are dispersed in the insulating matrix under the specific condition that the carbon nanotubes are in electrical contact with one another, whereby the sheet-shaped heating unit can exhibit a higher heat- radiation rate efficiency than the prior art heating unit even by addition of a relatively small amount of carbon nanotubes, and can also be easily molded into various structures. Furthermore, since the carbon nanotubes also act as a reinforcing agent, the mechanical properties such as the bending strength of the sheet-shaped heating unit are improved. In other words, the prior art sheet-shaped heating unit in which conductive carbon particles are dispersed in a polymer matrix achieves a desired resistance for heating only when a large amount of carbon particles are contained in the heating unit, resulting in the difficulty of molding and the deterioration of mechanical properties. Conversely, the sheet-shaped heating unit according to the present invention exhibits electrical conductivity comparable to that of the prior art sheet- shaped heating unit by dispersing only a small amount of carbon nanotubes in a matrix under a specific condition, and also does not suffer deterioration of its mechanical properties, while having moldability and pliability owing to the use of a small amount of additives, i.e., carbon nanotubes.
DETAILED DESCRH ION OF THE INVENTION
Carbon nanotubes used in the sheet-shaped heating unit of the present invention generally have the characteristic properties as described below.
The carbon nanotube, as seen in FIG. 1, has a diameter of 1 ~ 500 nm and a length of several μm ~ hundreds of μm and thus has a high isotropy in view of configuration. Moreover, the carbon nanotube has a conductivity of -lO^Ω, which means that the carbon nanotube is a conductor. The carbon nanotube is mechanically rigid (approximately 100 times more rigid than steel) and chemically stable and also has excellent thermal conductivity of 2000 W/mK. In addition, the carbon nanotube is hollow and thus has a lower density compared to graphite or carbon fibers as general carbon materials.
Due to the above properties, the carbon nanotube has a large L/R (length/radius) ratio of 100 ~ 10,000 and can act as a conductor in series with other carbon nanotubes when a current is fed thereto. Accordingly, even when a small amount of carbon nanotubes is used, the resulting heating unit can exhibit similar electrical conductivity to other heating units containing a large amount of different carbon materials. A multilayered wall carbon nanotube as well as a single- layered wall carbon nanotube can be adapted for the carbon nanotube in the present invention.
The addition amount of carbon nanotubes is, as mentioned above, 0.5 ~ 50% by weight, preferably 1 ~ 30% by weight, more preferably 3 ~ 20% by weight on the basis of the total weight of a heating complex, the heating complex comprising carbon nanotubes and a matrix. So long as the electrical connection of carbon nanotubes to one another can be achieved, a smaller amount of carbon nanotubes may be used in order to accomplish the object of the present invention.
The term "electrical contact" (sometimes, referred to as "electrical connection") as described in this disclosure means the condition wherein a carbon nanotube is in physical contact with other carbon nanotubes to conduct electricity therebetween. This term simultaneously means the condition wherein a carbon nanotube is spaced apart from other carbon nanotubes but the distance therebetween is in the range allowing electron tunneling to occur. In FIG. 2, there is illustrated an example wherein a plurality of carbon nanotubes 210 are dispersed in an electric insulating matrix 220, while being in electrical contact with one another.
A matrix used in the present invention is not particularly limited so long as it is a material which is thermo-conductive and thermo-stable and in which fine carbon nanotubes can be dispersed under a specific condition that the carbon nanotubes are in electrical contact with one another. Such a material includes, for example, but is not limited to polymer materials meeting the above requirements, and ceramic materials. Examples of the polymer material include, but are not limited to polyethylene (PE), polypropylene (PP), polystyrene (PS), polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinylchloride (PVC), phenol resins, urea resins, melamine resins, polyester resins, epoxy resins, diarylphthalate resins, polyurethane resins, silicone resins, etc. Among them, the polyester resins are more preferable in consideration of easy moldablility and include, for example, but are limited to unsaturated polyester resins, alkyd resins, polyethylene terephthalate, and the like. Examples of the ceramic material include, but are not limited to alumina (Al2O3), silica (SiO2), zirconia (ZrO2), etc.
To the sheet-shaped heating unit according to the present invention are connected electrodes, in an attachment or insertion manner, through which current is fed to induce heating of the heating complex when current is applied thereto. In an embodiment, an insulating material may be laminated to the outer surface of a heating complex comprising carbon nanotubes and a matrix so as to prevent electricity leakage resulting from exposure of the heating complex to the exterior.
In FIGS. 3 and 4, there are illustrated sheet-shaped heating units in which electrodes are connected to a heating complex in an attachment manner, respectively. Referring to FIG. 3, a sheet-shaped heating unit 100 is configured such that two electrodes 300 are attached to both lateral surfaces of a planar heating complex 200 and two insulators 400 cover the upper and lower surfaces of the electrodes 300 and heating complex 200. It should be noted that the heating complex 200 is not limited to a planar shape. As seen in FIG. 4, a sheet-shaped heating unit 101 may be configured such that two electrodes 201 are attached to both lateral surfaces of a heating complex 201 having a square cross-section.
In FIGS. 5 and 6, there are shown sheet-shaped heating units in which electrodes are connected to a heating complex in the insertion manner or the attachment/insertion manner. More specifically, in the insertion manner, one or more pairs of electrodes are inserted into a planar heating complex. Meanwhile, in the attachment/insertion manner, some portions of electrodes which are attached to both lateral surfaces of a heating complex having a square cross-section are extended to the inside of the heating complex. The sheet-shaped heating unit of the insertion manner or attachment/insertion manner is characterized by a higher heating efficiency than that of the sheet-shaped heating unit of the attachment manner.
Referring to FIG. 5, a heating complex 202 in which the upper and lower surfaces are attached to insulators 402 is configured in the insertion manner, such that a plurality of electrodes 503 pass through the inside of the heating complex 202 but are not attached to the outer surfaces thereof. Therefore, the sheet-shaped heating unit 202 in FIG. 5 can produce a greater amount of radiant heat than the sheet-shaped heating unit 200 in FIG. 3. A sheet-shaped heating unit 103 in FIG. 6 has a structure such that electrodes 301 as seen in FIG. 3 extend, in some portions thereof, to the inside of a heating complex 403 to form extended electrodes 503. These extended electrodes 503 are not in contact with one another and, preferably, are spaced apart from one another at a constant interval to ensure even heat radiation.
Electrodes as described above serve to induce the heating of a heating complex when current is applied thereto, and thus are not particularly limited so long as they are of a material having high conductivity. Such a highly conductive material includes, for example, but is not limited to metal plates such as silver plate, copper plate, aluminum plate, etc. and conductive composite plates of polymer or ceramic material containing a large amount of conductive materials such as metal particles, carbon powders, carbon nanotubes, etc.
For the purpose of increasing the performance of the sheet-shaped heating unit according to the present invention, the sheet-shaped heating unit may include other elements or be configured in other structures.
The present invention also provides a method for preparing the aforementioned sheet- shaped heating unit.
More specifically, a method for preparation of the sheet-shaped heating unit comprises the steps of,
adding 0.5 ~ 50% by weight of anisotropic carbon nanotubes with the length of several μm to hundreds of μm, on the basis of the total weight of a heating complex, to an electrically insulating matrix; and
dispersing the carbon nanotubes in the matrix such that the carbon nanotubes are in electrical contact with one another.
Where the matrix is composed of a polymer material, there can be employed a method whereby carbon nanotubes are mixed in liquid-phase monomers and then polymerized with the aid of a catalyst, or a method whereby the polymer is dissolved in a solvent to provide a liquid solution and carbon nanotubes are mixed in the solution and then the solvent is removed, but the method is not limited thereto.
Where the matrix is of a ceramic material, there can be employed a method whereby carbon nanotubes are mixed in a raw ceramic material and the resulting mixture is molded and dried, then sintered at high temperature, but the method is not limited thereto.
Methods for mixing carbon nanotubes in a matrix are not particularly limited so long as the carbon nanotubes are dispersed in the matrix with the carbon nanotubes being electrically connected to one another. Examples of mixing methods include, but are not limited to a mixing screw method, a shear mixer method, a melt blending method, etc. As mentioned previously, since the carbon nanotubes have a large L/R ratio, that is, a high anisotropy, the electrical connection thereof can be readily achieved when they are evenly dispersed. In the case where a heating complex is formed as a thin plate as seen in FIG. 3, the amount of carbon nanotubes used can be reduced in order to provide a sheet-shaped heating unit of the present invention. That is because the orientation of carbon nanotubes is optimized when a heating complex containing carbon nanotubes is coated on a separating film to form a thin plate, and the optimized orientation allows the electrical connection to be readily achieved. The resistivity of the sheet-shaped heating unit prepared thus is in the range of approximately 1 ~ 105 Ω Cm.
BRIEF DESCRIPTION OF DRA INGS
FIG. 1 is an electron micrograph of carbon nanotubes useful for the sheet-shaped heating unit of the present invention;
FIG. 2 is a schematic view of carbon nanotubes dispersed in a matrix, with the carbon nanotubes being electrically in contact with one another, in accordance with the present invention;
FIGS. 3 and 4 are schematic views of the sheet-shaped heating units according to some embodiments of the present invention, wherein electrodes are connected to heating complexes in the attachment manner, respectively;
FIGS. 5 and 6 are schematic views of the sheet-shaped heating unit according to some embodiments of the present invention, wherein electrodes are connected to heating complexes in the attachment/insertion manner, respectively.
Designation of the reference numerals
100, 101, 102, 103: sheet-shaped heating unit
200, 201, 202, 203: heating complex
210: carbon nanotube
220: electrically insulating matrix
300, 301, 302, 303: electrode
400, 402: insulator.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, the present invention will be described in more detail by EXAMPLES, but the scope of the present invention is not limited thereto.
EXAMPLE 1
Carbon nanotubes were prepared by a conventional thermal decomposition method in which ferrocene as a metallic catalyst is dissolved in benzene as a carbon stock and the resulting solution is heated at high temperature of 1000°C in an electric furnace to synthesize carbon nanotubes.
3 g of the synthesized carbon nanotubes and 97 g of polyester resin (unsaturated polyester resin: EPOVIA®; Craybelly Korea) were added in a mixer and mixed, thereafter a curing agent (methylethylketone-peroxide: MEK-PO) was added thereto. The resulting product was sprayed on a glass plate to form a sheet-shaped heating complex. The sheet-shaped heating complex was tailored to the size of 1 cm x 10 cm to make a specimen. Electrodes of an HP2000 multimeter (Hewlett-Packard) were placed on both lateral ends of the specimen to measure the resistivity thereof. The results are described in TABLE 1 below.
EXAMPLE 2
A specimen was prepared in the same manner as in EXAMPLE 1 except for using 95 g of the polyester resin and 5 g of the carbon nanotubes and the resistivity of the specimen was measured. The results are described in TABLE 1 below.
EXAMPLE 3
A specimen was prepared in the same manner as in EXAMPLE 1 except for using 94 g of the polyester resin and 6 g of the carbon nanotubes and the resistivity of the specimen was measured. The results are described in TABLE 1 below.
EXAMPLE 4
A specimen was prepared in the same manner as in EXAMPLE 1 except for using 93 g of the polyester resin and 7 g of the carbon nanotubes and the resistivity of the specimen was measured. The results are described in TABLE 1 below.
EXAMPLE 5
A specimen was prepared in the same manner as in EXAMPLE 1 except for using 90 g of the polyester resin and 10 g of the carbon nanotubes and the resistivity of the specimen was measured. The results are described in TABLE 1 below.
EXAMPLE 6
A specimen was prepared in the same manner as in EXAMPLE 1 except for using 80 g of the polyester resin and 20 g of the carbon nanotubes and the resistivity of the specimen was measured. The results are described in TABLE 1 below.
COMPARATIVE EXAMPLE
A specimen was prepared in the same manner as in EXAMPLE 1 except for not using carbon nanotubes and the resistivity of the specimen was measured. The results are described in TABLE 1 below.
[TABLE 1]
Figure imgf000012_0001
As seen in TABLE 1 above, the sheet-shaped heating units prepared in EXAMPLES 1 ~ 6 according to the present invention have low resistivity of 1 Ω-cm ~ 106 Ω-cm meeting the requirement for a good heating unit, while the sheet-shaped heating unit prepared in the COMPARATIVE EXAMPLE containing no carbon nanotubes was ascertained to have resistivity beyond 200 MΩ-cm, the detection limit of the resistance meter, which indicates that the material is practically an insulator.
INDUSTRIAL APPLICABILITY
As described above, the sheet-shaped heating unit according to the present invention has a high electrical conductivity even when a small amount of carbon nanotubes are contained therein, and can be readily molded in various structures, and has good mechanical properties such as bending strength. Furthermore, the carbon nanotubes have a higher thermal conductivity at 1800 ~ 6000 W/mK than that of conventional materials, thus the sheet-shaped heating unit of the present invention containing them exhibits excellent conductive properties without addition of ceramic materials, resulting in the reduction of manufacturing cost thereof.
As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described examples are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.

Claims

WHAT IS CLAIMED IS:
1. A sheet-shaped heating unit comprising anisotropic carbon nanotubes of the length of several μm to hundreds of μm at an amount of 0.5 to 50% by weight on the basis of the total amount of a heating complex, the carbon nanotubes being in electrical contact with one another in an electrically insulating matrix, in which said heating complex comprises the carbon nanotubes and the matrix.
2. The sheet-shaped heating unit according to claim 1, wherein said carbon nanotubes are single-layered wall and/or multilayered wall carbon nanotubes.
3. The sheet-shaped heating unit according to claim 1, wherein the amount of said carbon nanotubes in said heating complex is 1 to 30% by weight.
4. The sheet-shaped heating unit according to claim 1, wherein said matrix comprises a polymer material selected from the group consisting of polypropylene (PP), polyethylene (PE), polystyrene (PS), polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), phenol resins, urea resins, melamine resins, polyester resins, epoxy resins, diarylphthalate resins, polyurethane resins and silicone resins.
5. The sheet-shaped heating unit according to claim 1, wherein said matrix comprises a ceramic material selected from the group consisting of urnina (Al2O3), silica (SiO^ and zirconia (ZrO2).
6. The sheet-shaped heating unit according to claim 1, wherein said heating unit further includes electrodes which induce heating of said heating unit by applying current to said heating complex and which are connected to said heating complex in an attachment manner or an attachment/insertion manner.
7. A method for preparation of a sheet-shaped heating unit, comprising adding anisotropic carbon nanotubes of the length of several μm to hundreds of μm in an electrically insulating matrix at an amount of 0.5 to 50% by weight on the basis of the total amount of a heating complex comprising the carbon nanotubes and the matrix, and dispersing said carbon nanotubes in said matrix such that said carbon nanotubes are in electrical contact with one another.
8. The method according to claim 6, wherein said dispersing step is carried out by mixing said carbon nanotubes in liquid-phase monomers for said matrix and then polymerizing the monomer with the aid of a polymerization catalyst, or by dissolving a polymer material for said matrix in a solvent to make a liquid solution and mixing said carbon nanotubes in said solution, followed by the removal of the solvent.
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Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102007001132A1 (en) * 2007-01-03 2008-07-10 Recaro Gmbh & Co. Kg Vehicle seat, particularly motor vehicle seat, has seat component which is provided with seat heater that has carbon nano tubes as ohmic resistance
EP2043406A3 (en) * 2007-09-28 2009-10-28 Tsinghua University Plane heat source
WO2010006858A1 (en) * 2008-07-16 2010-01-21 Siemens Aktiengesellschaft Heating device for heating a glass surface, particularly of a protective glass of an outdoor camera, and electronic and/or optical device having a protective glass
DE102008059780B3 (en) * 2008-11-27 2010-05-27 Porzellanfabrik Hermsdorf Gmbh Rod-shaped ceramic resistant heating body useful for guide- and calendar rollers in polymer film technique, comprises carbon nanotubes embedded as electric conductive phase in a silicate- or oxide ceramic matrix
WO2010092178A1 (en) * 2009-02-16 2010-08-19 Mann+Hummel Gmbh Device for heating liquids
WO2010097099A1 (en) * 2009-02-27 2010-09-02 Siemens Aktiengesellschaft Electric component and method for producing an electric component
US8410676B2 (en) 2007-09-28 2013-04-02 Beijing Funate Innovation Technology Co., Ltd. Sheet-shaped heat and light source, method for making the same and method for heating object adopting the same
US8450930B2 (en) 2007-10-10 2013-05-28 Tsinghua University Sheet-shaped heat and light source
US20130233476A1 (en) * 2010-08-27 2013-09-12 Alliant Techsystems Inc. Out-of-autoclave and alternative oven curing using a self heating tool
TWI478617B (en) * 2009-04-30 2015-03-21 Hon Hai Prec Ind Co Ltd Method for making three-dimensional heat source
TWI501685B (en) * 2009-04-30 2015-09-21 Hon Hai Prec Ind Co Ltd Three-dimensional heat source
TWI501686B (en) * 2009-04-30 2015-09-21 Hon Hai Prec Ind Co Ltd Three-dimensional heat source
TWI501687B (en) * 2009-04-30 2015-09-21 Hon Hai Prec Ind Co Ltd Three-dimensional heat source
US20150303020A1 (en) * 2007-10-10 2015-10-22 Tsinghua University Method for making sheet-shaped heat and light source and method for heating object adopting the same
TWI513357B (en) * 2009-04-30 2015-12-11 Hon Hai Prec Ind Co Ltd Three-dimensional heat source
CN105428516A (en) * 2015-11-06 2016-03-23 中国空间技术研究院 Active-type infrared camouflage structure based on vanadium dioxide
EP3107353A4 (en) * 2014-02-13 2017-02-15 Korea Electronics Technology Institute Heating paste composition, surface type heating element using same, and potable low-power heater
EP3244692B1 (en) * 2016-05-10 2021-06-23 Airbus Operations GmbH Electrically heatable layer stack

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4980541A (en) * 1988-09-20 1990-12-25 Raychem Corporation Conductive polymer composition
JPH07111184A (en) * 1993-10-13 1995-04-25 Dairin Shoji:Kk Sheet-like heat-sensitive element, temperature sensor, temperature controller, and sheet-like heater
JPH07183078A (en) * 1993-12-24 1995-07-21 Mitsubishi Plastics Ind Ltd Self-temperature controlling, current-carrying heating element
JP2000058228A (en) * 1998-08-12 2000-02-25 Suzuki Sogyo Co Ltd Thin film resistance heating element and toner heating/ fixing member using it
JP2000215967A (en) * 1999-01-25 2000-08-04 Toto Ltd Sheet heater

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4980541A (en) * 1988-09-20 1990-12-25 Raychem Corporation Conductive polymer composition
JPH07111184A (en) * 1993-10-13 1995-04-25 Dairin Shoji:Kk Sheet-like heat-sensitive element, temperature sensor, temperature controller, and sheet-like heater
JPH07183078A (en) * 1993-12-24 1995-07-21 Mitsubishi Plastics Ind Ltd Self-temperature controlling, current-carrying heating element
JP2000058228A (en) * 1998-08-12 2000-02-25 Suzuki Sogyo Co Ltd Thin film resistance heating element and toner heating/ fixing member using it
JP2000215967A (en) * 1999-01-25 2000-08-04 Toto Ltd Sheet heater

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102007001132A1 (en) * 2007-01-03 2008-07-10 Recaro Gmbh & Co. Kg Vehicle seat, particularly motor vehicle seat, has seat component which is provided with seat heater that has carbon nano tubes as ohmic resistance
US8410676B2 (en) 2007-09-28 2013-04-02 Beijing Funate Innovation Technology Co., Ltd. Sheet-shaped heat and light source, method for making the same and method for heating object adopting the same
EP2043406A3 (en) * 2007-09-28 2009-10-28 Tsinghua University Plane heat source
US20150303020A1 (en) * 2007-10-10 2015-10-22 Tsinghua University Method for making sheet-shaped heat and light source and method for heating object adopting the same
US8450930B2 (en) 2007-10-10 2013-05-28 Tsinghua University Sheet-shaped heat and light source
US20130220990A1 (en) * 2007-10-10 2013-08-29 Hon Hai Precision Industry Co., Ltd. Method for making sheet-shaped heat and light source and method for heating object using the same
US8808049B2 (en) * 2007-10-10 2014-08-19 Tsinghua University Method for making sheet-shaped heat and light source
WO2010006858A1 (en) * 2008-07-16 2010-01-21 Siemens Aktiengesellschaft Heating device for heating a glass surface, particularly of a protective glass of an outdoor camera, and electronic and/or optical device having a protective glass
DE102008059780B3 (en) * 2008-11-27 2010-05-27 Porzellanfabrik Hermsdorf Gmbh Rod-shaped ceramic resistant heating body useful for guide- and calendar rollers in polymer film technique, comprises carbon nanotubes embedded as electric conductive phase in a silicate- or oxide ceramic matrix
WO2010092178A1 (en) * 2009-02-16 2010-08-19 Mann+Hummel Gmbh Device for heating liquids
WO2010097099A1 (en) * 2009-02-27 2010-09-02 Siemens Aktiengesellschaft Electric component and method for producing an electric component
TWI501685B (en) * 2009-04-30 2015-09-21 Hon Hai Prec Ind Co Ltd Three-dimensional heat source
TWI478617B (en) * 2009-04-30 2015-03-21 Hon Hai Prec Ind Co Ltd Method for making three-dimensional heat source
TWI501686B (en) * 2009-04-30 2015-09-21 Hon Hai Prec Ind Co Ltd Three-dimensional heat source
TWI501687B (en) * 2009-04-30 2015-09-21 Hon Hai Prec Ind Co Ltd Three-dimensional heat source
TWI513357B (en) * 2009-04-30 2015-12-11 Hon Hai Prec Ind Co Ltd Three-dimensional heat source
US20130233476A1 (en) * 2010-08-27 2013-09-12 Alliant Techsystems Inc. Out-of-autoclave and alternative oven curing using a self heating tool
EP3107353A4 (en) * 2014-02-13 2017-02-15 Korea Electronics Technology Institute Heating paste composition, surface type heating element using same, and potable low-power heater
US10536993B2 (en) 2014-02-13 2020-01-14 Korea Electronics Technology Institute Heating paste composition, surface type heating element using the same, and portable low-power heater
CN105428516A (en) * 2015-11-06 2016-03-23 中国空间技术研究院 Active-type infrared camouflage structure based on vanadium dioxide
EP3244692B1 (en) * 2016-05-10 2021-06-23 Airbus Operations GmbH Electrically heatable layer stack
US11122649B2 (en) 2016-05-10 2021-09-14 Airbus Operations Gmbh Electrically heatable layer stack

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