KR101488898B1 - TRANSPARENT HEATING SUBSTRATE USING CARBON NANO TUBE AND METHOD OF MANUFACTURING THE Substrate - Google Patents

Abstract

Disclosed is a transparent heating substrate using a carbon nanotube having a heating body which is transparent and whose heating temperature can be controlled by controlling the thickness, and a method for manufacturing the same. There is provided a transparent heating substrate using a carbon nanotube including a substrate and a heating layer using carbon nanotubes formed on the substrate. The method also includes preparing a substrate, preparing a carbon nanotube slurry mixture, applying the carbon nanotube slurry mixture to the substrate, and heat treating the substrate to which the carbon nanotube slurry has been applied A method of manufacturing a transparent heating element using carbon nanotubes is provided. A transparent heating substrate having excellent economical efficiency can be manufactured through a simple process. The transparent heat generating substrate of the present invention can control the thickness of the transparent heat generating layer to change the specific resistance of the heat generating layer. Thus, the heat generating temperature can be controlled within a wide range by a simple method.

Description

TECHNICAL FIELD [0001] The present invention relates to a transparent heat-generating substrate using carbon nanotubes, and a method of manufacturing the same. BACKGROUND ART [0002]

The present invention relates to a transparent heat generating substrate using carbon nanotubes and a method of manufacturing the same, and more particularly, to a transparent heat generating substrate using carbon nanotubes having a heat generating body which is transparent and capable of controlling a heating temperature by controlling its thickness, ≪ / RTI >

Nichrome wire or other metal heating element is widely used as a heating element in food cookers such as toasters and irons where heat is generally required.

However, since the metal heating element is an opaque material, it is difficult to visually confirm the heating process in the metal heating element. Therefore, it is common to set an appropriate cooking time by applying a separate timer or the like, or to estimate the time of the heating process by human intuition.

In addition, a heating element such as a heating wire which generates heat and an electric wiring for applying power to the heating element are complicatedly installed. In order to install such a heating element, a certain space is indispensably required, which leads to an increase in the volume of the device. Furthermore, since the electric power is supplied through a 220V voltage for home use, high voltage electrical insulation is required, and a large amount of electric power is consumed.

In order to solve these problems, the use of a transparent heating element using a transparent electrode made of indium tin oxide (ITO) has been proposed. This means that the conductivity is further enhanced by adding about 10 to about 10% of tin oxide (SnO ₂ ) to the conductive indium oxide (In ₂ O ₃ ). By sputtering ITO on a sputtering target, , A transparent conductive film can be obtained.

However, in this method, the indium (indium) price is high among the raw materials constituting the ITO, and the process of synthesizing and manufacturing the ITO raw material is not only difficult but also requires sputtering processing in a vacuum evaporator This is a very complex and tricky problem. In addition, it is possible to change the surface resistance from several ohms to several ohms (Ω) according to the manufacturing conditions in the case of ITO, It requires a lot of cost and difficult process.

Alternatively, a thin film formed using a carbon nanotube or a conductive polymer may be used. However, in this technique, it is generally difficult to lower the surface resistance to several hundreds of ohms or less without impairing transparency.

Therefore, it is demanded to manufacture a transparent heat generating element not only economically advantageous in terms of low power consumption, but also simple in terms of process, as well as being able to freely change a large amount of heat generation by easily adjusting the surface resistance.

Korean Patent No. 10-0915708 (Announced on September 4, 2009) Korean Registered Patent No. 10-0979538 (published on September 1, 2010) Korean Patent Publication No. 10-2011-0051347 (Published May 18, 2011)

Accordingly, it is a first object of the present invention to provide a carbon nanotube which can realize a transparent heating element, can control the heating temperature by controlling the thickness of the transparent heating element, and can easily control the temperature with low power, And to provide a transparent heat generating substrate using the same.

A second object of the present invention is to provide a method of manufacturing a transparent heating substrate using the carbon nanotubes.

In order to achieve the first object of the present invention, there is provided a transparent heating substrate using carbon nanotubes including a substrate and a heating layer using carbon nanotubes formed on the substrate.

According to another aspect of the present invention, there is provided a method of manufacturing a carbon nanotube slurry comprising the steps of preparing a substrate, preparing a carbon nanotube slurry mixture containing carbon nanotubes, a binder, a solvent and a dispersant, Coating a nanotube slurry mixture on the substrate, and heat treating the substrate coated with the carbon nanotube slurry. The present invention also provides a method of manufacturing a transparent heating element using carbon nanotubes.

According to the present invention, a transparent heating substrate having excellent economic efficiency can be manufactured through a simple process. The transparent heat generating substrate of the present invention can control the thickness of the transparent heat generating layer to change the specific resistance of the heat generating layer. Thus, the heat generating temperature can be controlled within a wide range by a simple method.

 Further, since the temperature can be controlled using an applied voltage of a low power of typically 40 V or less, it is excellent in terms of economy, and facilities and cost for insulation can be reduced.

When the transparent heat generating substrate according to the present invention is used in a cooker for heating and processing food, it is possible to observe a change in the state of the food placed inside the heating substrate in the heating process. Therefore, since the time of completion of the cooking of the food can be visually observed, it is possible to predict when the cooking is completed. Therefore, it is unnecessary to set a separate program or a timer to indicate the completion time of the cooking, and it is possible to know the exact cooking completion time. In addition, the cooking process can be confirmed visually, so that a cooking appliance that can generate visual interest can be manufactured.

Similarly, when the heat-generating substrate of the present invention is applied to an apparatus requiring heating such as an iron or a dish dryer, there is an advantage that the degree of heating and the degree of drying of the dish can be visually confirmed.

On the other hand, when the transparent heat generating substrate of the present invention is attached to a bath mirror, it is possible to prevent fogging of the mirror, thereby keeping the mirror in a clear state. In addition, when the transparent heat generating substrate according to the present invention is installed in the bottom of the dishwasher, the residual moisture in the dishwasher can be dried to remove the fungal growth after the completion of the washing.

1 is a perspective view illustrating a transparent heat generating substrate using carbon nanotubes according to an embodiment of the present invention.
2 is a cross-sectional view illustrating the transparent heat generating substrate of FIG.
3 is a flowchart illustrating a method of manufacturing a transparent heating substrate using carbon nanotubes according to an embodiment of the present invention.
4 is a flow chart for explaining another embodiment of a method of manufacturing a transparent heat generating substrate using carbon nanotubes according to the present invention.
5 is a perspective view showing an application example of a transparent heat generating substrate using carbon nanotubes according to the present invention.

Hereinafter, a transparent heating substrate using carbon nanotubes according to preferred embodiments of the present invention and a method of manufacturing the same will be described in detail with reference to the accompanying drawings.

First, the present invention provides a transparent heating substrate using carbon nanotubes. FIG. 1 is a perspective view illustrating an embodiment of a transparent heat generating substrate using carbon nanotubes according to the present invention, and FIG. 2 is a cross-sectional view illustrating the transparent heat generating substrate of FIG.

Referring to FIGS. 1 and 2, a heating substrate 10 according to an embodiment of the present invention includes a substrate 100. The substrate 100 serves as a base on which the carbon nanotube heating layer 100 described later is formed.

In the present invention, it is preferable that the heating object surrounded by the heating substrate 10 or the heating substrate 10 can be observed from the outside of the heating substrate 10, and since heat is generated, Materials with good transparency and excellent heat resistance can be selected.

That is, it is preferable to use a transparent synthetic resin substrate, a general glass substrate, a tempered glass substrate, or the like having excellent heat resistance, and more specifically, a heat resistance temperature level required by a product to which the present heat generating substrate 10 is applied, Therefore, substrates of different materials may be selected and used depending on the applied product.

When the above synthetic resin is used, it is preferable to use a synthetic resin such as polymethyl methacrylate (PMMA), polytetrafluoroethylene (PTFE), or polycarbonate (PC), which satisfy both transparency and heat resistance in various synthetic resins You can choose to use it.

The heating substrate according to an embodiment of the present invention includes a carbon nanotube heating layer 200 formed on the substrate.

Specifically, the carbon nanotube heating layer 200 is formed by applying a carbon nanotube slurry on the substrate 100 and then performing heat treatment. Specifically, the carbon nanotube heating layer includes 60 to 80 parts by weight of carbon nanotubes, 3 to 10 parts by weight of a binder, and 5 to 15 parts by weight of a solvent and a dispersant.

The carbon nanotubes (CNTs) are formed of six carbon hexagons connected to each other to form a tubular shape, and the diameter of the tube is only several to several tens of nanometers. These carbon nanotubes have an electrical conductivity similar to that of copper, and their thermal conductivity is as good as diamond, and their strength is 100 times better than steel. In addition, carbon fiber is broken even when it is deformed by only 1%, while carbon nanotubes have durability that can withstand 15% deformation.

When the carbon nanotube is used in an amount less than 60 parts by weight, the conductivity is lowered and the amount of heat generated is insufficient. On the other hand, when the carbon nanotubes are used in an amount exceeding 80 parts by weight, the amount of the binder is relatively small, so that the carbon nanotubes can not be stably and firmly formed on the substrate 100.

In particular, when the heat-generating substrate according to the present invention is used in an apparatus in which heating and cooling are repeated frequently, such as a toaster and a dish dryer, if the carbon nanotube component is used in an amount of 80 parts by weight or more, The layer 200 may be peeled off.

As the binder, a polyacrylic, polyurethane, polyester, or polyolefin resin may be used, or a mixture thereof may be used. The binder is mixed with the carbon nanotubes to smoothly generate heat when power is applied, and to securely and uniformly form the carbon nanotubes on the substrate 100. When the amount of the binder is less than 3 parts by weight, the ink or paste can not be used. On the other hand, when the amount of the binder is more than 10 parts by weight, the conductivity is lowered.

Also, the carbon nanotube slurry includes 5 to 15 parts by weight of a solvent and a dispersant. The solvent and the dispersant may be, for example, isopropyl alcohol (IPA) mixed with a component of a dispersion component, and a dispersing agent such as Triton X-100 may be used as a dispersant. The solvent and the dispersant are preferably used in an amount of 85 to 99% by weight of a solvent and 1 to 15% by weight of a dispersant.

The solvent and the dispersant serve to uniformly disperse and mix the carbon nanotubes and the binder in the slurry. If the solvent and the dispersant are used in an amount of less than 5 parts by weight, the viscosity of the slurry becomes high and it becomes difficult to coat the entire surface of the substrate 100 with a uniform thickness, and it is difficult to expect a uniform dispersion effect. On the other hand, when the solvent and the dispersing agent are used in an amount exceeding 15 parts by weight, the dispersion effect and uniformity of coating are not improved and the heat treatment time to be described later is increased.

And may further comprise 1 to 5 parts by weight of glass frit, if necessary. Glass frit is a kind of powder glass for electronic materials which is excellent in mechanical strength and chemical durability. In the present invention, when a glass frit is used, a net-like matrix is formed so that the heat generating layer including the carbon nanotube component is more uniform and the airtightness is improved, so that it can be firmly attached to the substrate. Therefore, it is possible to generate uniform heat on the entire surface of the heat generating substrate, and to prevent the heat generating layer from peeling off the substrate

When the glass frit is used in an amount of less than 1 part by weight, the degree of improvement of the adhesion performance is insignificant, and an effect distinct from the case where glass frit is not added can not be expected. When the glass frit is used in an amount exceeding 5 parts by weight, And the temperature can not be finely controlled by adjusting the thickness of the exothermic layer.

In the heating substrate 10 according to the present invention, the specific resistance of the heating substrate can be controlled by controlling the thickness of the heating layer 200 using the carbon nanotubes, and the heating amount is controlled as the specific resistance is changed. As a result, The heating temperature can be easily controlled by adjusting the thickness of the heating plate 200.

That is, in the present invention, it is the key to controlling the heating temperature of the device to make the coating thickness of the heating layer uniform and to precisely control the coating thickness. For this purpose, as described above, in order to control the coating thickness precisely, not only the carbon nanotubes and the binder must be mixed in the carbon nanotube slurry in the above-described ratio, but the viscosity of the slurry is in the range of 5,000 to 20,000 cP .

In order to supply power to the heat generating substrate 10 according to the present embodiment, an electrode 300 formed on the carbon nanotube heating layer 200 and a power supply line 400 ). ≪ / RTI >

As shown in FIGS. 1 and 2, the electrodes are formed on both sides of the heating layer 200 and are formed by printing a conductor such as copper, silver, gold, or the like, Wire or the like.

The present invention provides a method of manufacturing a transparent heating substrate using the carbon nanotubes. 3 is a flowchart illustrating a method of manufacturing a transparent heating substrate using carbon nanotubes according to an embodiment of the present invention.

Referring to FIG. 3, the method for fabricating a transparent heat generating substrate according to the present invention includes the steps of preparing a substrate (step S100), preparing a carbon nanotube slurry (step S200), forming a carbon nanotube slurry mixture on the substrate (Step S300), and heat treating the substrate coated with the carbon nanotube slurry (step S400).

First, a method of manufacturing a transparent heating substrate according to this embodiment includes preparing a substrate (step S100). It is preferable that the heating object surrounded by the heating substrate 10 or the heating substrate 10 can be observed through the substrate and since heat is generated, heat resistance must be provided. Therefore, a material having transparency and excellent heat resistance is selected . Therefore, it is possible to prepare a substrate of a material having excellent heat resistance and transparency by cutting to a size suitable for a device to be applied. Examples of the substrate 100 include glass, tempered glass, polymethyl methacrylate (PMMA), polytetrafluoroethylene (PTFE), and polycarbonate (PC) You can choose to use it.

The method for fabricating a transparent heating substrate according to the present embodiment includes preparing a carbon nanotube slurry (step S200).

The carbon nanotube slurry has carbon nanotubes, a binder, a solvent, and a dispersant. As described above, the composition of the slurry includes about 60 to 80 parts by weight of carbon nanotubes, about 3 to 10 parts by weight of the binder, 5 to 15 parts by weight of a solvent and a dispersant, and 1 to 5 parts by weight of glass frit may be further used depending on the use of the transparent heat generating substrate and the heating temperature.

Polyester resin, polyurethane resin, polyester resin, and polyolefin resin are used as the binder of one of the raw materials of the heat source. After the carbon nanotube raw material, the solvent and the dispersant are mixed and dispersed, the slurry is uniformly stirred to give 5,000 To 20,000 cP.

The present invention regulates the resistivity and the exothermic temperature by controlling the thickness of the applied exothermic layer, so it is particularly necessary to apply the exothermic layer uniformly. At the same time, when the exothermic temperature is usually controlled to 40 to 120 DEG C, which is used in domestic drying or food cooking equipment, the thickness of the exothermic layer is only several to several tens of mu m. Therefore, it is necessary to finely adjust the coating thickness.

For this purpose, it is preferable that the viscosity range is 5,000 to 20,000 cP. If the viscosity is less than 5,000 cP, it is difficult to precisely control the coating thickness due to excessive dilution. On the other hand, if it is more than 20,000 cP, it becomes too sticky, and it becomes difficult to uniformly coat the entire surface of the substrate so as not to cause a local difference in thickness.

Next, a method for manufacturing a transparent heat generating substrate according to this embodiment includes coating the carbon nanotube slurry on the substrate (step S300).

In this step, the prepared slurry is coated on the substrate in an appropriate thickness according to the heating temperature to be obtained by using a silk screen and various printing methods.

Subsequently, the method for manufacturing a transparent heat generating substrate according to this embodiment includes a step of heat treating the substrate coated with the carbon nanotube slurry (step S400).

In this step, the substrate coated with the slurry is subjected to a heat treatment at a temperature of about 80 to 120 DEG C in an atmospheric pressure environment rather than a vacuum chamber to volatilize the organic substances and the solvent contained in the slurry. By this process, a heating layer is formed on the substrate.

As another embodiment of the method for manufacturing a transparent heat generating substrate according to the present invention, the method may further include an electrode forming step (step S500) and a power line forming step (step S600).

4 is a flow chart for explaining another embodiment of a method of manufacturing a transparent heat generating substrate using carbon nanotubes according to the present invention.

Referring to FIG. 4, steps S100 to S400 of an embodiment related to a method of manufacturing a transparent heat generating substrate are performed, and then electrodes are formed on the heat-treated substrate using a conductive material (step S500) (Step S600). Here, the electrode may be formed by forming a conductive material such as copper, gold, or silver on a screen printing method.

The transparent heat generating substrate thus manufactured can be applied to various applications. 5 is a perspective view showing an application example of a transparent heat generating substrate using carbon nanotubes according to the present invention.

Referring to Fig. 5, this shows that a transparent heat generating substrate is applied to a toaster for baking a bread. When the outer housing of the toaster is made of a transparent material and the heating plate installed in the housing is used as the transparent heat-generating substrate according to the present invention, when the bread is put in a toaster and operated, the process of baking the bread can be visually confirmed.

Therefore, it is possible to stop the operation of the apparatus when the bread is baked more precisely, rather than installing a separate timer or the like. In addition, it can be applied to various devices requiring heat generation.

For example, it can be easily attached to existing power circuit, display circuit and audio circuit. It can be installed on the bottom of dish dryer, bathroom mirror, electric iron, or on the bottom of the dishwasher (faucet) Can be prevented.

Hereinafter, specific examples and experimental examples of the present invention will be described in more detail. It should be understood, however, that the embodiments and examples are for the purpose of promoting understanding of the specific examples of the invention described above, and the scope of rights and the like should not be construed thereby.

Example

[Example 1]

1. Toughened glass with a thickness of 3 mm was prepared, each of which was cut to a width of 13 cm for use in a toast machine.

2. A mixture of 6.8 g of multi-walled carbon nanotubes (Carbon Nanotec, Korea) and 0.52 g of polyurethane resin, 0.97 g of a solvent and 0.097 g of Triton X-100 mixed with 0.91 g of isopropyl alcohol as a dispersant, And the mixture was stirred in a stirrer for 20 minutes. The viscosity measured after stirring was 12,000 cP.

3. The prepared slurry was applied to the tempered glass substrate in a thickness of 0.81 탆 by a silk screen method.

4. Next, the tempered glass substrate was heat-treated at a temperature of about 110 DEG C for 30 minutes to form a heating layer. At this time, the measured thickness of the heating layer was 0.65 mu m.

5. Then, silver (Ag) was printed on both sides of the heating substrate to form a pair of electrode patterns.

6. Finally, a power line is connected to the electrode so as to apply power.

[Example 2]

The same procedure as in Example 1 was carried out except that the slurry coating thickness of item 3 was 1.58 탆 and the thickness of the heating layer measured in item 4 was 1.35 탆.

[Example 3]

The same procedure as in Example 1 was carried out except that the slurry coating thickness of item 3 was 3.58 탆 and the thickness of the heating layer measured in item 4 was 3.21 탆.

[Experimental Example]

The resistivity and the exothermic temperature after 3 minutes were measured by applying a power of 38 V to the transparent heat generating substrate manufactured according to Examples 1 to 3 and summarized in Table 1 below.

[Table 1]

According to the experimental results, it was found that the exothermic temperature showed a large difference by finely adjusting the thickness of the exothermic layer in the order of μm, and a sufficiently high calorific value was exhibited even when a relatively small voltage (38 V) was used.

10: transparent heat generating substrate 100: substrate
200: Carbon nanotube heating layer 300: Electrode
400: Power supply line

Claims (10)

Board; And a carbon nanotube heating layer formed on the substrate to a thickness of several micrometers to several tens of micrometers, wherein the carbon nanotube substrate is used for a cooker in which heating and cooling are repeated,
The carbon nanotube heating layer
60 to 80 parts by weight of carbon nanotubes;
3 to 10 parts by weight of a binder selected from the group consisting of polyacrylic, polyurethane, polyester and polyolefin resins;
5 to 15 parts by weight of a solvent and a dispersant; And
And 1 to 5 parts by weight of glass frit. The glass substrate according to claim 1, wherein the substrate is glass. Wherein the transparent substrate is made of glass, tempered glass, poly methly methacrylate (PMMA), polytetrafluoroethylene (PTFE), or polycarbonate (PC). delete delete delete The method according to claim 1,
An electrode formed on the carbon nanotube heating layer; And
And a power supply line connected to the electrode and applying power to the electrode. A method for manufacturing a transparent heating substrate using carbon nanotubes used in a cooker in which heating and cooling are repeated,
Preparing a substrate;
60 to 80 parts by weight of carbon nanotubes and 3 to 10 parts by weight of a binder selected from the group consisting of polyacrylic, polyurethane, polyester and polyolefin resins, 5 to 15 parts by weight of a solvent and a dispersant, Preparing a carbon nanotube slurry mixture having a viscosity of 5,000 to 20,000 cP, which is formed by stirring a mixture of a carbon nanotube, a binder, and a solvent and a dispersant;
Coating the carbon nanotube slurry on the substrate to a thickness of several mu m to several tens of mu m; And
And heat treating the substrate to which the carbon nanotube slurry is applied. delete 8. The method of claim 7, wherein the heat treatment is performed at a temperature of 80 to 120 degrees Celsius. 8. The method of claim 7, further comprising: forming an electrode on the heat-treated substrate;
And connecting a power supply line to the electrode. ≪ Desc / Clms Page number 20 >

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