KR20160120475A - Coating solutions for thermally conductive composite with dispersion stability, preparation method thereof, and thermal conductive and heat dissipative coating layer using the same - Google Patents

Abstract

TECHNICAL FIELD The present invention relates to a thermally conductive composite coating solution improved in dispersion stability which can maintain a stable state without phase separation for a long time by using an inorganic filler surface-modified with silane, a method for producing the same, and a thermally conductive and heat-

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermally conductive composite coating solution having improved dispersion stability, a process for producing the same, and a heat conduction and heat-

The present invention relates to a thermally conductive composite coating solution having improved dispersion stability, a process for producing the same, and a thermally conductive and heat-radiating coating film using the same.

Next-generation electronic devices are increasingly becoming thinner, thinner, and multifunctional, and are increasingly integrated. Therefore, countermeasures against heat emission problems due to an increase in thermal density are required. Such heat emission is closely related to device reliability and service life. Development of high heat dissipation composite materials with excellent thermal conductivity and high thermal conductivity used in these next generation electronic devices is a very important and important factor for improving heat dissipation performance, so it must be developed.

Most of the materials of the high-heat-insulating sheet are composite materials in which a high thermal conductive filler material and a polymer material are mixed. The reason for using the composite material is to combine the excellent adhesion of the polymer material with the high thermal conductivity of the inorganic filler material in order to take advantage of each material. The prior art related to a high heat dissipation composite material having such excellent insulation properties and high thermal conductivity is as follows.

Korean Patent No. 1205503 discloses an inorganic filler mixture comprising at least one of a spherical inorganic filler and a plate-like inorganic filler; A mixture of at least one of aluminum nitride and boron nitride; And a flame retardant, wherein the resin composition for a thermally conductive heat-radiating sheet comprises 30 to 100 parts by weight of a silicone-modified epoxy resin having an average epoxy equivalent of 400 to 1000, and the polyfunctional epoxy resin having a bifunctionality or more is 30 To 100 parts by weight, the phenoxy resin is 30 to 100 parts by weight, the butadiene acrylonitrile copolymer rubber is 20 to 50 parts by weight, and the polyvinyl butyral resin is 20 to 50 parts by weight. Discloses a resin composition for a conductive heat-radiating sheet.

In Korean Patent No. 1392880, impression graphite powder; And an organic binder containing a super-screen alkyd resin and a diluent, wherein the impregnated graphite powder and the super-screen alkyd resin are contained in a weight ratio of 10 to 30: 100, and the impression graphite powder has an average particle size of 10 to 30: 80 < RTI ID = 0.0 > pm. ≪ / RTI >

However, in this prior art, inorganic particles entering the additive in preparing a low viscosity composite or composition composition for making a film or film have a high self-density and a low solubility in solvent, However, in the process of storing the mixed composition solution after the preparation, the mixture is precipitated within a few minutes within a few minutes, resulting in phase separation. As a result, the storage stability of the composite composition is very low, .

Korean Patent No. 1392880

In order to solve the problems of the prior art described above, the inventors of the present invention have made intensive studies on a coating solution capable of producing a highly heat-dissipative composite material having a high thermal conductivity to exhibit high dispersion stability even when the viscosity is low, The present invention has been completed.

Accordingly, it is an object of the present invention to provide a thermally conductive composite coating solution which does not cause phase separation for a long time at a low viscosity and has excellent storage stability and does not cause deterioration of the final product, and a method for producing the same.

In order to achieve the above object, the present invention provides a coating solution for a thermally conductive heat dissipation coating, which comprises 20% by weight of polymer resin, 15 to 65% by weight of graphite powder, inorganic filler 15 To 65% by weight and a solvent. The thermally conductive composite material of the present invention can form a thermally conductive composite coating solution with improved dispersion stability that can maintain a stable state without phase separation for a long time by using an inorganic filler surface-modified with silane.

In one embodiment of the present invention, the polymer resin may be an epoxy resin, an acrylic resin, a copolymer or complex thereof, or the like.

In one embodiment of the present invention, the graphite powder may be an expanded graphite powder having an average particle size of 3 to 30 탆.

In one embodiment of the present invention, the inorganic filler surface-modified with the silane is at least one selected from the group consisting of aluminum (Al), alumina (AlO), silicon carbide (SiC), aluminum nitride (AlN), boron nitride (BN) An inorganic filler is used which is surface-modified by bonding a silane group having an ionic or non-polar terminal group to the surface of an inorganic filler selected from the groups.

In one embodiment of the present invention, the content of the inorganic filler surface-modified with the silane is preferably less than 15 times the content of the graphite powder.

In one embodiment of the present invention, a mixed solution of methyl ethyl ketone and toluene may be used as the solvent.

In one embodiment of the present invention, the present invention provides a thermally conductive composite material coating solution further comprising 7 to 25% by weight of a dispersion stabilizer based on 100 parts by weight of the solvent.

In one embodiment of the present invention, the dispersion stabilizer may include nonionic polyoxyethylene octylphenylether (Triton X-100), polyoxyethylene nonylphenol ethoxylate (NP-10), polyoxyethylene sorbate (Tween 20), and octyl phenol ethoxylate And the like.

In addition, the present invention provides a method for preparing an inorganic filler, comprising the steps of: adding an inorganic filler to an alkali solution and stirring the mixture at a temperature of from room temperature to 100 ° C for 1 to 5 hours to form a hydroxylamine; Reacting the hydroxylated inorganic filler with a silane compound having an ionic or non-polar end group for 5 to 12 hours under an alcohol-based solvent at room temperature to reflux condition to modify the surface thereof to silane; And mixing the inorganic filler surface-modified with the silane, the polymer resin, the graphite powder, the dispersion stabilizer, and the solvent to prepare a coating solution for a thermally conductive composite coating solution.

In one embodiment of the present invention, the inorganic filler is selected from the group consisting of aluminum (Al), alumina (AlO), silicon carbide (SiC), aluminum nitride (AlN), boron nitride (BN) Can be used.

In one embodiment of the present invention, 0.1 M NaOH aqueous solution can be used as the alkali solution.

In one embodiment of the present invention, methanol or ethanol solvent may be used as the alcohol-based solvent.

In one embodiment of the present invention, trialkoxysilane can be used as the silane compound.

In one embodiment of the present invention, the polymer resin may be an epoxy resin, an acrylic resin, or a mixture or complex thereof, and a mixed solution of methyl ethyl ketone and toluene is used as the solvent, Nonionic type oxidized polyethylene may be used as the stabilizer.

The present invention also provides a coating film formed by coating the above-mentioned thermoconductive composite composition coating solution on a substrate.

The present invention provides a thermally conductive composite coating solution and a process for producing the same, wherein phase separation does not occur for a long period of time at a low viscosity and storage stability is excellent, so that the final formed heat radiation coating film does not deteriorate in physical properties, And exhibits excellent effects.

FIG. 1 is a schematic view illustrating a process for preparing an inorganic filler surface-modified with silane used in a method for preparing a thermally conductive composite coating solution according to an embodiment of the present invention.
2 is a graph showing the results of XPS analysis of pure alumina powder used in Examples 1 to 8 and alumina powder surface-modified with silane.
3 is a graph showing XPS analysis results of pure aluminum powder used in Examples 9 to 14 and aluminum powder surface-modified with silane.
4A to 4F are SEM photographs showing the results of measurement of dispersion characteristics of the thermoconductive composite coating solution in Experimental Example 2 of the present invention.
5 is a schematic view illustrating a method of measuring a heat radiation temperature of a coating film formed of a thermally conductive composite coating solution in Experimental Example 3 of the present invention.

Hereinafter, the present invention will be described in detail.

Unless defined otherwise, all technical terms used in the present invention have the following definitions and are consistent with the meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Also, preferred methods or samples are described in this specification, but similar or equivalent ones are also included in the scope of the present invention. The contents of all publications referred to herein are incorporated herein by reference.

The term "about" is used herein to refer to a reference quantity, a level, a value, a number, a frequency, a percent, a dimension, a size, a quantity, a weight, or a length of 30, 25, 20, 25, 10, 9, 8, 7, Level, value, number, frequency, percent, dimension, size, quantity, weight or length of a variable, such as 4, 3, 2 or 1%.

Throughout this specification, the words "comprises" and "comprising ", unless the context requires otherwise, include the steps or components, or groups of steps or elements, Steps, or groups of elements are not excluded.

A method of preparing a thermally conductive composite coating solution according to an embodiment of the present invention will be described in detail below.

First, the inorganic filler is added to the alkali solution, and the mixture is stirred at room temperature to 100 ° C for 1 to 5 hours to form a hydroxyl. Specifically, as shown in FIG. 1, an inorganic filler is added to an alkali solution such as 0.1 M NaOH solution or the like, and the mixture is stirred at room temperature to 100 ° C for 1 to 5 hours to hydroxylate the surface to bind a hydroxyl group.

The inorganic filler usable in the present invention may be selected from the group consisting of aluminum (Al), alumina (AlO), silicon carbide (SiC), aluminum nitride (AlN), boron nitride (BN) The filler preferably has an average particle size of 2 to 50 mu m. When the particle size of the inorganic filler used is small, the cohesive force of the particles themselves becomes strong, which makes it difficult to uniformly disperse in the composite composition. In the case of larger particles, the compatibility with other fillers and resins in the composition is lowered, Large pore or phase separation occurs in the structure of the micropores.

Next, the hydroxylated inorganic filler is reacted with the silane compound under an alcoholic solvent at room temperature to reflux condition for 5 to 12 hours to surface-modify the surface thereof with silane having an ionic or non-polar terminal group. According to one embodiment of the present invention, the hydroxylated inorganic filler is surface-modified to react with a silane compound in an alcohol-based solvent such as methanol or an ethanol solvent for 5 to 12 hours at room temperature to reflux condition to bond a silane group thereto (See Fig. 1).

Examples of the silane compound that can be used in the present invention include trialkoxysilane, (RO) 3SiR ', 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, 3- Propyltrimethoxysilane, and the like, but not always limited thereto.

As described above, the inorganic filler surface-treated with silane has excellent compatibility with a polar solvent such as alcohol if the terminal group of the chemically modified silane is ionic. If the terminal group of the silane is non-polar, the inorganic filler having excellent compatibility with the organic solvent So that it is possible to improve dispersion characteristics for various solvents.

Finally, the inorganic filler surface-modified with the silane, the polymer resin, the graphite powder and the solvent are mixed.

In one embodiment of the present invention, 20% by weight of polymer resin, 15 to 65% by weight of graphite powder, 15 to 65% by weight of inorganic filler surface-modified with silane, and solvent are mixed with 100 parts by weight of solvent, To prepare a coating composition solution.

The polymer resin used in the present invention may be an epoxy resin, an acrylic resin, a mixture thereof, or a composite thereof in order to form a coating film.

As the graphite powder used in the present invention, it is preferable to use an expanded graphite powder having an average particle size of 3 to 30 탆. The particle size of graphite is usually several micrometers to several hundred micrometers. If the particle size is too large, uniform dispersion with the inorganic filler in the composition solution becomes difficult and it becomes difficult to control the optimum viscosity of the composition dispersion.

The content of the inorganic filler surface-modified with the silane in the thermoconductive composite coating solution according to the present invention is preferably less than 15 times the content of the graphite powder. When the inorganic filler surface-modified with silane is used at 15 times or more as much as the graphite powder, phase separation due to precipitation of the inorganic filler tends to occur with time, which is not preferable.

As the solvent used in the thermoconductive composite coating solution according to the present invention, a mixed solution of methyl ethyl ketone and toluene (1/1 v / v) may be used, but the present invention is not limited thereto.

The thermoconductive composite coating solution according to the present invention may further contain a curing agent of a polymer resin to be used, for example, an amine-based curing agent such as triethyltetramine when an epoxy resin is used.

Also, in the thermoconductive composite coating solution according to the present invention, the dispersion stabilizer may further comprise 7 to 25% by weight of a dispersion stabilizer based on 100 parts by weight of the solvent. As the dispersion stabilizer, a nonionic dispersion stabilizer such as nonionic type oxidized polyethylene or the like can be used. Since the thermal conductivity of the coating film formed using the thermoconductive composite coating solution according to the present invention is inversely proportional to the amount of the dispersion stabilizer used, the thermal conductivity of the coating film is lowered when the dispersion stabilizer exceeds 25% by weight of the dispersion stabilizer relative to 100 parts by weight of the solvent It is not preferable.

When the dispersion stabilizer is used together with the silane-surface-modified inorganic filler, the dispersion stability can be further improved. That is, when the dispersion stabilizer is used in combination with the inorganic filler surface-modified with silane, dispersion stability can be further improved.

The coating film coated with the thermoconductive composite coating solution prepared according to the present invention has excellent thermal conductivity and heat dissipation properties.

[Production Examples 1 to 8] Preparation of alumina (Al2O3) powder surface-modified with silane

Alumina powder (average particle size 2 to 50 μm) was hydroxylated by stirring in 0.1 M aqueous NaOH solution at room temperature for 5 hours, and then the alumina powder was reacted with trialkoxysilane in a methanol solvent at room temperature for 10 hours And dried at 85 ° C in a dry oven to prepare an alumina powder surface-modified with silane.

Hereinafter, the present invention will be described in detail with reference to Examples and Experimental Examples. However, the present invention is not limited thereto.

[Examples 1 to 8] Preparation of thermally conductive composite coating solution

The epoxy resin and the curing agent shown in Table 1 were prepared by mixing 1.8 g of an epoxy resin composed of bisphenol A and epichlorohydrin and 0.2 g of triethylene tetramine as a curing agent and the graphite powder was expanded graphite powder having an average particle size of 6 탆 / m * K) was used. As the inorganic filler, alumina powder surface-modified with the silane obtained in the above-mentioned Production Example was used. Nonionic ionomer polyethylene oxide (Triton-X 100) was used as a dispersion stabilizer. A mixed solution of ketone and toluene mixed at a ratio of 1: 1 was used.

The alumina powder surface-treated with the silane was dispersed in 1.8 g of an epoxy resin (MW? 700 Struers Epofix) composed of bisphenol A and epichlorohydrin for 24 hours, And the mixture was stirred for 24 hours in a 50 DEG C oil bath using a mechanical stirrer. To the stirred mixture was added 0.2 g of triethyltetramine (hardener Struers Epofix) and Triton-X to continue stirring so that the filler was uniformly dispersed without aggregation. To prepare the epoxy composite resin composition as a coating solution, a solvent (MEK (methyl ethyl ketone) / Toluene = 1/1 v / v) was added to adjust the viscosity to prepare a thermoconductive composite coating solution.

division Epoxy resin and curing agent Graphite powder Inorganic filler Dispersion stabilizer menstruum Example 1 2g 6.5 g 1.5 g 8g 30 mL Example 2 2g 4g 4g 4g 10 mL Example 3 2g 1.5 g 6.5 g 2g 20 mL Example 4 2g 1g 7g 1g 5 mL Example 5 2g 1g 7g - 5 mL Example 6 2g 0.5 g 7.5g 2g 5 mL Example 7 2g 0.5 g 7.5g 1g 5 mL Example 8 2g 0.5 g 7.5g - 5 mL

[Comparative Example 1]

A thermally conductive composite coating solution was prepared in the same manner as in Examples 1 to 8 except that pure alumina powder was used as an inorganic filler and the components and the content of the components shown in Table 2 were used.

division Epoxy resin and curing agent Graphite powder Inorganic filler Dispersion stabilizer menstruum Comparative Example 1 2g 4g 4g - 10 mL

[Production Examples 9 to 14] Preparation of aluminum powder surface-modified with silane

Alumina powder (average particle size 2 to 50 μm) was hydroxylated by stirring in 0.1 M aqueous NaOH solution at room temperature for 5 hours, and then the alumina powder was reacted with trialkoxysilane in a methanol solvent at room temperature for 10 hours And dried at 85 ° C. in a dry oven to prepare an alumina powder surface-modified with silane

[Examples 9 to 14] Preparation of thermally conductive composite coating solution

The epoxy resin and the curing agent shown in Table 3 were prepared by mixing 1.8 g of an epoxy resin composed of bisphenol A and epichlorohydrin and 0.2 g of a curing agent (triethylenetetramine), and the graphite powder was an expanded graphite powder having an average particle size of 6 m (Triton-X 100) was used as a dispersion stabilizer, and methyl (3-methyl-2-pyrrolidone) as a solvent was used as the inorganic filler. A mixed solution of ethyl ketone and toluene mixed at a ratio of 1: 1 was used.

The aluminum powder surface-treated with the silane was dispersed in 1.8 g of an epoxy resin (MW? 700 Struers Epofix) composed of bisphenol A and epichlorohydrin for 24 hours, And the mixture was stirred for 24 hours in a 50 DEG C oil bath using a mechanical stirrer. To the stirred mixture was added 0.2 g of triethyltetramine (hardener Struers Epofix) and Triton-X to continue stirring so that the filler was uniformly dispersed without aggregation. To prepare the epoxy composite resin composition as a coating solution, a solvent (MEK (methyl ethyl ketone) / Toluene = 1/1 v / v) was added to adjust the viscosity to prepare a thermoconductive composite coating solution.

division Epoxy resin and curing agent Graphite powder Inorganic filler Dispersion stabilizer menstruum Example 9 2g 6.5 g 1.5 g 8g 30ml Example 10 2g 1g 7g 4g 5ml Example 11 2g 1g 7g 2g 5ml Example 12 2g 0.5 g 7.5g 2g 5ml Example 13 2g 0.5 g 7.5g 1g 5ml Example 14 2g 0.5 g 7.5g - 5ml

[Comparative Example 2]

A thermally conductive composite coating solution was prepared in the same manner as in Examples 9 to 14 except that pure aluminum powder was used as an inorganic filler and the ingredients and the content of ingredients shown in Table 4 were used.

division Epoxy resin and curing agent Graphite powder Inorganic filler Dispersion stabilizer menstruum Comparative Example 2 2g 4g 4g - 10 mL

[Experimental Example 1] X-ray photoelectron spectroscopy (XPS) analysis

The pure alumina powder used in Examples 1 to 8 and the alumina powder surface-modified with silane were analyzed by XPS and shown in Fig. Referring to FIG. 2, the Si content of the pure alumina powder (pAO) before the surface treatment is about 1% or less, while the Si content is about 2.2% for the alumina powder (Si-pAO) .

Further, the pure aluminum powder and the aluminum powder surface-modified with silane used in Examples 9 to 14 were analyzed by XPS and shown in FIG. Referring to FIG. 3, pure aluminum powder (pAl) before surface treatment shows Si of impurity level of about 1% or less, whereas Si content is increased by about 1.7% in silane-surface-modified aluminum powder (Si-pAl) .

[Experimental Example 2] Measurement of dispersion characteristics of a thermoconductive composite coating solution

Dispersion characteristics of the thermoconductive composite coating solution prepared in Examples 1 to 14 and Comparative Examples 1 and 2 were measured as follows, and the results are shown in FIGS. 4A to 4F.

Measurement method of dispersion characteristics: CK means carbon content, AlK means aluminum and alumina content, Matrix zaf means corrected value. Composite compositions were prepared and after 5 hours, top and bottom powders were collected by Vacuum Filteration System, dried and analyzed by EDAX. As a result of analysis, it can be confirmed that the particle distribution of AlK (aluminum, alumina) is not greatly different as indicated by a red solid line when 7 to 25% by weight of the nonionic dispersion stabilizer is contained. This is considered to be excellent in dispersion characteristics.

Referring to FIG. 4A, in Comparative Examples 1 and 2 in which the inorganic filler was not surface-modified with silane, the inorganic filler was precipitated in the thermally conductive composite coating solution with the lapse of time, resulting in phase separation .

Example 7 and Example 13 were compared with the dispersion characteristics of Example 8 and Example 14, respectively. As a result, when the nonionic dispersion stabilizer was applied together with the inorganic filler surface-modified with silane (1 to 8 g) , Indicating that dispersion stability was improved even with a small amount, and even when 1 g was used, dispersion stability was improved. Therefore, it can be seen that the inorganic filler and the dispersion stabilizer, which are surface modified with silane, are more effective in terms of dispersion stability when used in combination.

[Experimental Example 3] Measurement of thermal conductivity of a film obtained from a thermally conductive composite coating solution

The thermal conductivity of the coating film formed by spin-coating the thermoconductive composite coating solution prepared in Examples 1 to 14 at 50 ° C for 2 hours was measured according to the following method. The results are shown in Table 5.

The thermal conductivity was measured using LFA447 (Netzch) equipment. The sample size was 8 × 8, 1.5t. The measurement temperature range was analyzed at room temperature.

Density (g / cm ³⁾ Thermal conductivity (W / m * K)
Out-of-plane Example 1 1.336 0.292 Example 2 1.267 0.487 Example 3 1.212 0.787 Example 4 1.955 0.993 Example 5 2.230 1.085 Example 6 1.415 0.776 Example 7 1.598 0.906 Example 8 1.729 1.109 Example 9 1.433 0.301 Example 10 2.110 1.002 Example 11 2.265 1.118 Example 12 1.442 0.767 Example 13 1.753 0.912 Example 14 1.798 1.121

[Experimental Example 4] Measurement of heat radiation characteristics of a film obtained from a thermally conductive composite coating solution

Al 6061 (40 mm x 40 mm, t = 10 mm) used as the material of the heat sink was coated with the Al plate (40 mm x 40 mm, t = 10 mm) in order to measure the heat radiation characteristics at the interface when used for the heat radiation coating in the thermoconductive composite coating solution prepared in Examples 1 to 14 Respectively. The thermally conductive composite coating solutions prepared in Examples 1 to 14 were evenly coated on the Al plate, cured at 50 ° C for 2 hours and dried to prepare a coating film. In order to compare the effects of the heat-radiating coating, the heat radiation temperature was measured simultaneously on the Al plate not coated with the surface under the same conditions, and the results are shown in Tables 6 and 7. In the process of measuring the heat radiation temperature, it proceeded in an enclosed space to prevent the change of convection. In this case, T1 means the medium generating heat by the role of light source, T2 is heat conduction in which heat is generated in T1, and T3 is heat dissipation temperature in which conduction heat is emitted from T2 to the atmosphere.

Temperature
(° C) Al
plate Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 T1 100.2
± 0.3 100.6
± 0.1 100.2
± 0.1 100.2
± 0.1 100.1
± 0.1 100.2
± 0.1 100.1
± 0.1 100.2
± 0.1 100.1
± 0.1 T2 97.1
± 0.2 97.7
± 0.2 95.6
± 0.3 97.1
± 0.1 97.1
± 0.2 97.1
± 0.1 97.1
± 0.2 97.1
± 0.1 97.1
± 0.2 T3 52.7
± 0.3 54.3
± 0.1 54.2
± 0.1 55.4
± 0.2 54.5
± 0.3 55.4
± 0.2 54.4
± 0.2 55.2
± 0.2 55.3
± 0.2

Temperature
(° C) Al plate Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 T1 100.2
± 0.3 100.3
± 0.1 100.1
± 0.1 100.2
± 0.1 100.1
± 0.1 100.2
± 0.1 100.2
± 0.1 T2 97.1
± 0.2 98.0
± 0.3 96.4
± 0.2 96.9
± 0.1 96.4
± 0.2 96.8
± 0.1 96.6
± 0.1 T3 52.7
± 0.3 53.3
± 0.4 53.8
± 0.3 54.4
± 0.2 53.9
± 0.1 54.7
± 0.1 54.1
± 0.2

Referring to Tables 6 and 7, it can be seen that the heat radiation temperature of all the Al plates coated with the thermoconductive composite coating solution of the present invention is higher than that of the Al plate not coated with the thermally conductive composite coating solution. Even if the thermal conductivity is low (less than 1.0), the heat dissipation temperature is measured at a value similar to that of the composition coating having a high thermal conductivity (1.0 or more). All Al plates coated with the thermoconductive composite coating solution have improved heat radiation temperature .

Referring to the above results, it can be seen that the coating film coated with the thermoconductive composite coating solution prepared according to the present invention has excellent dispersion stability and excellent heat conduction characteristics and heat radiation characteristics.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined by the appended claims. It is therefore intended that such variations and modifications fall within the scope of the appended claims.

Claims (15)

A coating solution for a thermally conductive heat radiation coating,
And 15 to 65% by weight of an inorganic filler surface-modified with silane having an ionic or non-polar terminal group, with 20% by weight of a polymer resin, 15 to 65% by weight of a graphite powder, Material coating solution. The method according to claim 1,
Wherein the polymer resin is selected from an epoxy resin, an acrylic resin, and a composite material thereof. The method according to claim 1,
Wherein the graphite is an expanded graphite powder having an average particle size of 3 to 30 占 퐉. The method according to claim 1,
The inorganic filler surface-modified with silane may be added to the surface of an inorganic filler selected from the group consisting of aluminum (Al), alumina (AlO), silicon carbide (SiC), aluminum nitride (AlN), boron nitride (BN) Wherein the inorganic filler is an inorganic filler having a surface modified with a silane group bonded thereto. The method according to claim 1,
Wherein the content of the inorganic filler surface-modified with the silane is less than 15 times the content of the graphite powder. The method according to claim 1,
Wherein the solvent is a mixed solution of methyl ethyl ketone and toluene. The method according to claim 1,
Further comprising 7 to 25% by weight of a dispersion stabilizer based on 100 parts by weight of the solvent. 8. The method of claim 7,
Wherein the dispersion stabilizer is a non-ionic oxidized polyethylene. Adding an inorganic filler to an alkali solution and stirring the mixture at a temperature of from room temperature to 100 ° C for 1 to 5 hours to form a hydroxylamine;
Reacting the hydroxylated inorganic filler with a silane compound having an ionic or non-polar end group for 5 to 12 hours under an alcohol-based solvent at room temperature to reflux condition to modify the surface thereof to silane; And
Mixing a silane-modified inorganic filler, an epoxy resin, an acrylic resin, and a polymer resin selected from the above composites, a graphite powder, a dispersion stabilizer, and a solvent;
≪ / RTI > 10. The method of claim 9,
Wherein the inorganic filler is selected from the group consisting of aluminum (Al), alumina (AlO), silicon carbide (SiC), aluminum nitride (AlN), boron nitride (BN) ≪ / RTI > 10. The method of claim 9,
Wherein the alkali solution is 0.1 M NaOH aqueous solution. 10. The method of claim 9,
Wherein the alcohol-based solvent is methanol or an ethanol solvent. 10. The method of claim 9,
Wherein the silane compound is trialkoxysilane. ≪ RTI ID = 0.0 > 11. < / RTI > 10. The method of claim 9,
Wherein the solvent is a mixed solution of methyl ethyl ketone and toluene, and the dispersion stabilizer is non-ionic oxidized polyethylene. A heat conduction and heat radiation coating film formed by applying the thermally conductive composite material coating solution according to any one of claims 1 to 8 on a substrate.

Images