KR102079080B1 - Manufacturing method of thermally conductive coatings based on carbon materials with high-dispersion - Google Patents

Abstract

Disclosed is a method for producing a highly dispersible carbon material based heat dissipating coating.
Method for producing a heat dissipation coating agent according to an embodiment of the present invention comprises a first step of activating the carbon material by reacting the carbon material and ozone (O ₃ ); A second step of introducing a fluorine functional group into the carbon material by reacting the activated carbon material with the fluorine gas through the first step; And a third step of preparing a heat dissipation coating agent by mixing the carbon material into which the fluorine functional group is introduced through the second step in a coating solution.

Description

Manufacturing method of thermally conductive coatings based on carbon materials with high-dispersion

The present invention relates to a method for manufacturing a heat dissipating coating, and more particularly, to a method for manufacturing a heat dissipating coating that can obtain excellent heat dissipation performance by manufacturing a heat dissipating coating using a carbon material that has undergone an activation step and a fluorine functional group introduction step. will be.

BACKGROUND OF THE INVENTION Electrical and electronic components that have been used recently generate more heat due to weight reduction, miniaturization, and high integration. The generated heat is a cause of malfunction of electrical and electronic components or peripheral components, shortening the lifespan due to deterioration, etc. Recently, researches for effectively removing the generated heat have been actively conducted.

For example, LED (Light Emitting Diode), one of the electrical and electronic components, has relatively high energy consumption and high efficiency, and its use is increasing at a very high speed, but the life is reduced due to failure to adequately handle the generated heat. I still have In general, when the operating temperature of the LED module rises 10 ℃, it is known that the life is reduced by 2 times, and various studies are being conducted to effectively dissipate heat generated for long life and high efficiency, which is an advantage of the LED.

Recently, as one of means for releasing generated heat, a technique using a heat dissipating coating has been proposed.

However, the technology using a conventional heat dissipating coating is not sufficient heat dissipation performance, the fine particles contained in the coating is not uniformly dispersed and at the same time the microparticles agglomerate with each other, cracks occur in the cured heat dissipating coating, the heat dissipating coating and the substrate There exists a problem of this peeling.

Republic of Korea Patent Registration No. 10-1420051 (July 18, 2017 announcement)

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a heat dissipating coating having excellent heat dissipation performance as compared with the conventional.

Still another object of the present invention is to provide a heat dissipating coating that can improve the dispersibility of the coating and at the same time prevent agglomeration between particles, thereby preventing cracking and peeling from the substrate.

The object of the present invention is not limited to the above, other objects not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, the present invention provides a method for producing a highly dispersible carbon material-based heat dissipation coating agent, the method for producing a heat dissipation coating agent according to an example of the present invention, the carbon material by reacting the carbon material and ozone (O ₃ ) Activating a first step; A second step of introducing a fluorine functional group into the carbon material by reacting the activated carbon material with the fluorine gas through the first step; And a third step of preparing a heat dissipation coating agent by mixing the carbon material into which the fluorine functional group is introduced through the second step in a coating solution.

The first step is preferably carried out in a condition containing 0.1 to 5wt% ozone.

In addition, the first step is preferably made for 1 to 20 minutes.

The second step is preferably performed under a condition that the partial pressure of the fluorine gas is 0.1 to 0.5 bar in an inert gas atmosphere.

In addition, the second step is preferably made for 1 to 60 minutes in the temperature range of 25 to 300 ℃.

The coating solution may include a binder and a curing agent, and in the third step, it is preferable to mix 5 to 50 parts by weight of the carbon material based on 100 parts by weight of the coating solution.

The binder is preferably an organic polymer containing at least one functional group selected from vinyl groups, acrylic groups, urethane groups, epoxy groups, amino groups, and imide groups capable of thermal polymerization at both ends of the carbon chain or side chains of the carbon chain.

According to the present invention described above, it is possible to obtain a heat dissipation coating agent having excellent heat dissipation performance as compared with the prior art.

In addition, according to the present invention, it is possible to improve the dispersibility of the coating and at the same time prevent the aggregation between the particles, it is possible to obtain a heat-dissipating coating that can prevent cracking and peeling with the substrate.

The effects of the present invention are not limited to those described above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

FIG. 1 is a view illustrating a state in which carbon materials according to Examples and Comparative Examples are mixed with acetone, stirred, and left for 30 minutes to confirm dispersion performance of carbon materials according to Examples and Comparative Examples of the present invention. One picture.
FIG. 2 is a photograph of a thermal imaging camera for measuring a heat radiation performance of a heat radiation coating agent according to Examples and Comparative Examples of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings, examples, and test examples.

The present invention provides a method for producing a highly dispersible carbon material-based heat dissipation coating agent, the method for producing a heat dissipation coating agent according to an example of the present invention, the first step of activating the carbon material by reacting the carbon material and ozone (O ₃ ); A second step of introducing the fluorine functional group into the carbon material by reacting the activated carbon material with the fluorine gas through the first step; And a third step of preparing a heat dissipation coating agent by mixing the carbon material into which the fluorine functional group is introduced through the second step in a coating solution.

The carbon material may be used as long as it is known as a carbon material having high thermal conductivity. For example, the carbon material may be selected from the group consisting of graphite, carbon nanotubes, graphene, and mixtures thereof. However, it is preferable to use graphite which is relatively easy to introduce functional groups and has excellent dispersibility, but is not necessarily limited thereto.

In the first step, the carbon material is reacted with ozone (O ₃ ) to activate the carbon material. This step is carried out to give an active point to the carbon material in order to introduce the fluorine functional group to the carbon material more effectively in a later step.

The reaction between the carbon material and ozone may be performed in an air atmosphere, and the reaction is preferably performed for 1 to 20 minutes under the condition containing 0.1 to 5 wt% ozone. In addition, the reaction may be all at room temperature or above room temperature. That is, in the process of reacting the carbon material and ozone, the temperature may be set in various ways.

In the reaction between the carbon material and ozone, if the ozone content condition and reaction time are less than the lower limit, the carbon material and ozone may not react sufficiently, and thus the carbon material may not be sufficiently activated. If the ozone content and reaction time exceeds the upper limit, excessive fluorine functional groups are introduced at a later stage due to excessive activation and excessive activation, which may cause structural deformation of the carbon material. .

The carbon material activated through the first step as described above reacts with the fluorine gas in the second step to introduce fluorine functional groups into the carbon material.

The fluorine gas may be introduced from various materials including pure fluorine and fluorine. For example, fluorine, boron trifluoride, nitrogen trifluoride, and mixtures thereof may be used. That is, the fluorine gas referred to herein is a concept of referring to various materials including pure fluorine gas and fluorine.

The second step is preferably performed under a condition in which the partial pressure of the fluorine gas is 0.1 to 0.5 bar in an inert gas atmosphere, preferably for 1 to 60 minutes in the temperature range of 25 to 300 ℃.

Performing the second step in an inert gas atmosphere is to minimize the unwanted side reactions and to ensure the stability of the process.

If the partial pressure, reaction temperature and reaction time of the fluorine gas in the second step is less than the lower limit, there is a risk that the fluorine functional groups may not be sufficiently introduced into the carbon material, and the partial pressure, reaction temperature and reaction time of the fluorine gas may be When the upper limit is exceeded, there is no difference between the upper limit and the amount of the fluorine functional groups introduced, and rather, it is not preferable because there is a possibility that unwanted structural deformation occurs due to overreaction, thereby lowering the heat radiation performance.

After the second step, the fluorine functional group is introduced into the carbon material. Thereafter, in the third step, the carbon material and the coating solution introduced with the fluorine functional group are mixed to prepare a heat dissipation coating agent.

The coating solution may use a variety of coating solutions known in the art. However, since the present invention is to prepare a heat dissipation coating agent by mixing a carbon material introduced with a fluorine functional group, the coating solution is preferably used as follows.

That is, the coating solution includes a binder and a curing agent.

Since the present invention is for producing a heat-dissipating coating agent using a carbon material introduced with a fluorine functional group, the binder is a vinyl group, acrylic group, urethane group, epoxy group, capable of thermal polymerization at both ends of the carbon chain or side chain of the carbon chain, It is preferable that it is an organic polymer containing at least 1 functional group chosen from an amino group and an imide group.

In addition, although various kinds of hardeners may be used, repeated experiments have shown that polyamide is most effective. However, in the present invention, the curing agent is not limited to polyamide, and various kinds of curing agents may be used.

In addition, the coating solution may be further mixed with a diluent and various additives for adjusting the concentration of the heat dissipating coating. Considering the kind of the carbon material into which the fluorine functional group is introduced and the binder made of the above-mentioned organic polymer, the diluent consists of mono-epoxy, di-epoxy, tri-epoxy, phenylglycidyl ether, acetone, toluene and xylene. At least one selected from the group is preferably used, but is not necessarily limited thereto.

Hereinafter, the present invention will be described in more detail with reference to Examples and Test Examples.

Example  : Fluorine functional group end  Introduced Carbonaceous  Produce

Graphite powder was used as the carbon material.

The dried graphite powder was put into a reactor and reacted for 10 minutes in an air atmosphere containing 0.3 wt% of ozone to activate graphite.

Thereafter, the inside of the reactor was evacuated, the inert gas was injected and evacuated three times, and then a mixed gas of fluorine gas having a partial pressure of 0.4 bar and argon gas having a partial pressure of 0.6 bar was introduced into the reactor to react with graphite for 30 minutes. The fluorine functional group was introduced into the carbon material.

Comparative example

A carbon material manufactured through the same process as in Example 1 except for reacting ozone with graphite was prepared as Comparative Example 1, and a carbon material manufactured through the same process as in Example, except for reacting fluorine gas with graphite. Was used as Comparative Example 2, and pure graphite powder was used as Comparative Example 3.

Distributed performance

In order to confirm the dispersion performance of the carbon material according to the above Examples and Comparative Examples, the carbon material according to the Examples and Comparative Examples was mixed with acetone and stirred, and left for 30 minutes, and photographed after the state shown in FIG. It was. At this time, the carbon material and acetone were mixed so as to be 1: 5 by weight ratio.

As can be seen from the results of FIG. 1, the carbon material according to the embodiment of the present invention was confirmed to have excellent dispersion state even after elapse of time. From this, it can be expected that the heat dissipation coating agent produced using the carbon material according to the embodiment of the present invention will have excellent heat dissipation performance.

Element Content Measurement and Structural Analysis

Elemental content measurement and structural analysis of the carbon material according to the examples and comparative examples were carried out. For accurate measurement and analysis, the carbon materials according to the examples and the comparative examples were all dehydrated in a vacuum drying oven.

First, X-ray photoelectron spectroscopy (XPS) analysis was performed using a Thermo Fisher Scientific VG Multilab 2000 model.

In addition, X-ray diffraction (XRD) analysis was performed using PANalytical's X'Pert PRO model for structural analysis. The analysis was carried out by irradiation of Cu KαX-rays at room temperature, and the interlayer distance d ₀₀₂ of graphite was calculated from the height and half width of the peak at 2θ around 26, and the results are shown in the table below.

As can be seen from the results of the above table, the carbon material according to the embodiment of the present invention and the carbon material according to Comparative Example 1 prepared through the reaction of fluorine gas and graphite were able to confirm that the fluorine functional group was introduced. In addition, the carbon material according to the embodiment of the present invention reacted with the fluorine gas after the activation step through the reaction with ozone is introduced compared to the carbon material according to Comparative Example 1 that did not undergo the activation step through the reaction with ozone. It was confirmed that the content of fluorine increased.

From this, when the carbon material is activated through the reaction with ozone prior to the reaction with the fluorine gas for introducing the fluorine functional group, it was confirmed that the content of the introduced fluorine is increased.

In addition, since the value of d ₀₀₂ which means the interlayer spacing calculated from the XRD results was not significantly different, it was found that even when ozone and fluorine gas were reacted with the carbon material, there was no significant change in the structure of the carbon material.

Heat dissipation performance

In order to confirm the heat dissipation performance, the carbon material according to Examples and Comparative Examples of the present invention was mixed with the coating solution to prepare a heat dissipation coating agent, and then it was cured by coating the copper foil with a thickness of 200 μm using a doctor blade. After the LED was turned on in a state where it was attached to the LED substrate, the temperature after 10 minutes was measured by a thermal imaging camera, and the results thereof are shown in FIG. 2 and the following table.

At this time, epoxy was used as a binder and polyamide was used as a curing agent. The mixing ratio of the carbon material, the binder, and the curing agent was 1: 3: 0.5 by weight ratio.

As can be seen from the results of FIG. 2 and the table, it was confirmed that the heat dissipation performance of the heat dissipation coating agent prepared according to the embodiment of the present invention was the best.

Comparing Example 1 and Comparative Example 1 using a carbon material in which a fluorine functional group was introduced to the carbon material through reaction with fluorine gas, more fluorine functional groups were introduced by activating the carbon material through reaction with ozone. It was confirmed that the heat dissipation performance of the heat dissipation coating agent prepared by the embodiment of the present invention is more excellent.

In addition, Comparative Example 1 in which the fluorine functional group was introduced into the carbon material through the reaction with fluorine gas was found to have superior heat dissipation performance as compared with Comparative Example 2 and Comparative Example 3 in which the fluorine functional group was not introduced. Comparing Comparative Example 2 and Comparative Example 3, which did not proceed, it was confirmed that Comparative Example 2 had better heat dissipation performance than Comparative Example 3, because the dispersion state was improved as the carbon material was activated through reaction with ozone. I think it was.

From the above results, the heat radiation coating agent according to the present invention manufactured by activating the carbon material through the reaction with ozone and then introducing the fluorine functional group through the reaction with fluorine gas has a higher heat dissipation performance than the conventional one. It can be seen that the width is improved.

Embodiments of the present invention described above and illustrated in the drawings should not be construed as limiting the technical spirit of the present invention. The scope of protection of the present invention is limited only by the matters described in the claims, and those skilled in the art can improve and change the technical idea of the present invention in various forms. Therefore, such improvements and modifications will fall within the protection scope of the present invention as long as it will be apparent to those skilled in the art.

Claims (7)

A first step of activating the carbon material by reacting the carbon material and ozone at room temperature in the air atmosphere containing 0.1 to 5wt% ozone (O ₃ );
A second step of introducing the fluorine functional group into the carbon material by reacting the activated carbon material through the first step with the fluorine gas in an inert gas atmosphere having a partial pressure of fluorine gas of 0.1 to 0.5 bar; And
And a third step of preparing a heat dissipation coating agent by mixing the carbon material into which the fluorine functional group has been introduced through the second step to the coating solution.
delete The method of claim 1,
The first step is a method for producing a heat dissipating coating, characterized in that made for 1 to 20 minutes.
delete The method of claim 1,
The second step is a method for producing a heat-dissipating coating, characterized in that for 1 to 60 minutes in the temperature range of 25 to 300 ℃.
The method of claim 1,
The coating solution includes a binder and a curing agent,
In the third step, the method for producing a heat-dissipating coating, characterized in that for mixing 5 to 50 parts by weight of the carbon material based on 100 parts by weight of the coating solution.
The method of claim 6,
The binder is an organic polymer containing at least one functional group selected from vinyl groups, acrylic groups, urethane groups, epoxy groups, amino groups, and imide groups capable of thermal polymerization at both ends of the carbon chain or side chains of the carbon chain. Method for producing a heat dissipating coating.

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