KR20160095519A - Hybrid heat radiating sheet based on carbon nanotube and fabrication method thereof - Google Patents

Abstract

The present invention relates to a heat radiating sheet and, more specifically, to a hybrid heat radiating sheet, a polymer composite comprising the same, and a manufacturing method thereof. The heat radiating sheet mixes a carbon nanotube (CNT) and graphite or metal particles to improve a heat radiating feature so as to obtain flexibility.

Description

TECHNICAL FIELD [0001] The present invention relates to a carbon nanotube-based hybrid heat-radiating sheet and a method of manufacturing the same. BACKGROUND ART < RTI ID = 0.0 >

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat dissipation sheet, and more particularly, to a heat dissipation sheet which is formed by mixing carbon nanotubes (CNTs) selected from the group consisting of graphite, metal particles, The present invention relates to a hybrid heat-radiating sheet having flexibility and a manufacturing method thereof.

Recent developments in semiconductor patterning technology, such as photolithography and electron beam lithography, have led to the generation of a large amount of heat as electronic components and components of optical devices become highly integrated and miniaturized. As a result of the generated high temperature heat, There is a problem. Particularly, due to such a problem, the operation life of light emitting diodes (LEDs), which are widely applied in the lighting industry, is extremely short, and a phenomenon that a device does not operate as much as a desired light output is occurring. Accordingly, as a solution to the above problem, there is a demand for development of a flexible heat-radiating sheet which can be used for small-sized / thin-type electronic products having high thermal conductivity characteristics.

Carbon nanotubes have been extensively studied as flexible heat-radiating sheet materials that can be used in small / thin electronic appliances having high thermal conductivity characteristics. The flexible heat-radiating sheet can be manufactured by a method such as electrospinning or vacuum filtration, and the thickness and size of the heat-radiating sheet can be adjusted.

Single-walled carbon nanotubes are high thermal conductivity materials with a thermal conductivity of over 2,000 W / mK and can be applied as flexible heat-dissipating sheet materials. However, the heat-radiating sheet manufactured using only carbon nanotubes has a low value of ~ 10 W / mK or less, and thus it is difficult to efficiently discharge heat generated from the device to the outside. The reason for this low thermal conductivity value when manufacturing a heat spread sheet is due to thermal contact resistance, long heat path, and pore / air gap.

U.S. Patent Publication No. 2014/0052037 discloses that a sheet-shaped polymer composite in which carbon nanotubes are dispersed has thermal conductivity characteristics.

Korean Patent Laid-Open Publication No. 2011/0094635 also discloses a graphite heat-radiating sheet comprising a carbon nanotube as a thermally conductive pressure-sensitive adhesive. The heat-radiating sheet is prepared by coating a mixture of a carbon nanotube, an acrylate polymer, and a dispersant on one surface or both surfaces of a graphite sheet with a thermoconductive adhesive. However, the conventional techniques are merely to examine the thermal conductivity of the composite prepared by simply dispersing the carbon nanotubes in a polymer matrix, or they are difficult to process in view of coating components other than carbon nanotubes with the adhesive on the graphite sheet .

SUMMARY OF THE INVENTION An object of the present invention is to provide a hybrid heat radiation sheet which is flexible without a binder using carbon nanotubes, graphite or metal particles and has improved heat radiation characteristics in a vertical / horizontal direction, and a method of manufacturing the same. However, the problems to be solved by the present invention are not limited to the problems described above, and other problems not described can be clearly understood by those skilled in the art from the following description.

In order to accomplish the above object, the carbon nanotube-based heat-radiating sheet of the present invention is characterized in that in order to compensate for the disadvantages of the thermal contact resistance, the long heat path, and the air gap / air gap, The density of the sheet was adjusted to improve the thermal conductivity.

Further, the carbon nanotube / graphite hybrid heat radiation sheet mixed with graphite, the carbon nanotube / metal particle hybrid heat radiation sheet using metal particles, or the flexible heat radiation having further improved heat radiation property through the carbon nanotube / graphite / metal particle hybrid heat radiation sheet Sheet.

The carbon nanotube / graphite hybrid heat-radiating sheet, the carbon nanotube / metal particle hybrid heat-radiating sheet, or the carbon nanotube / graphite / metal particle hybrid heat-radiating sheet may be fabricated using a vacuum filtration process.

A carbon nanotube-based heat dissipation sheet / polymer composite can be prepared by mixing a polymer such as epoxy with a hybrid heat dissipation sheet based on the carbon nanotube.

The present invention relates to a method for producing a polymer composite having heat dissipation properties, in which carbon nanotubes, graphite or metal particles are not simply dispersed in a polymer matrix as in a conventional method, but a heat- Were prepared.

As described above, according to the present invention, it is possible to manufacture a carbon nanotube-based heat radiation sheet that is flexible and improved in heat radiation characteristics in the vertical and horizontal directions. Ultrasonic processing and vacuum filtration were used to fabricate a hybrid heat - radiating sheet using carbon nanotubes and graphite or metal particles. In order to reduce the thermal contact resistance between carbon nanotubes and graphite or metal particles, a heat treatment process was performed at an elevated temperature using an electric furnace.

The graphite or metal particles used together with the carbon nanotubes reduce many thermal contact resistances and long heat paths, thereby improving the thermal conductivity and reducing the void / air gap present in the carbon nanotube heat-radiating sheet As a result, the heat dissipation property is improved.

The thin carbon nanotube-based heat-radiating sheet according to the present invention has improved heat radiation characteristics in the vertical and horizontal directions and at the same time has a flexible characteristic, and thus can dissipate heat of high temperature generated in electronic devices, optical devices, The effect of improving the characteristics of the device can be expected. It is also expected that the operating life of the device will increase.

1 is a process flow chart of Example 1. Fig.
2 is a scanning electron microscope (SEM) image showing the graphite ratio of the carbon nanotube / graphite hybrid heat-radiating sheet.
FIG. 3 shows the results of thermal conductivity according to the graphite ratio of the carbon nanotube / graphite hybrid heat-radiating sheet.
4 is a process flow chart of the second to fourth embodiments.
5 is a SEM image of the fabricated carbon nanotube / Sn metal particle hybrid heat-radiating sheet.
6 is a SEM image of the fabricated carbon nanotube / SnAgCu metal particle hybrid heat-radiating sheet.
7 is a SEM image of the carbon nanotube / organic Ag (organic silver) hybrid heat-radiating sheet.
8 is a process flow chart of the eighth embodiment.
9 is a process flow chart of Comparative Example 1. Fig.
10 is a SEM image of the prepared carbon nanotube / graphite-containing polymer (PBT) composite.

Hereinafter, embodiments and examples of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. It should be understood, however, that the present invention may be embodied in many different forms and is not limited to the embodiments and examples described herein. In order to clearly explain the present invention in the drawings, parts not related to the description are omitted.

Throughout this specification, when an element is referred to as "including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise.

As used herein, the term "about" is used in its sense or approximation to the manufacturing and material tolerances inherent in the meanings mentioned, and is intended to cover either an exact or absolute value It is used to prevent unauthorized intruders from exploiting the mentioned disclosure.

Also, throughout the present specification, the phrase " step "or" step "does not mean" step for.

Hereinafter, embodiments of the present invention are described in detail, but the present invention is not limited thereto.

According to an aspect of the present invention, there is provided a carbon nanotube sheet comprising a carbon nanotube selected from the group consisting of graphite, metal particles, or a combination thereof and having a thermal conductivity of 2.5 to 9 W / mK, to provide. The binder is present between the graphite and the metal particles and the carbon nanotubes to enhance bonding of the two materials. In the case of a general carbon nanotube composite, the binder includes a conductive polymer or an insulating polymer as a binder. And the binder is not included in the production of the nanotube sheet. Carbon nanotubes are a kind of carbon allotrope with a cylindrical tube structure composed of hexagonal carbon bonds, and have a diameter of several nm. These carbon nanotubes are hollow and lightweight, and have tensile strengths up to 100 times higher than those of the same thickness steel, and have properties that bend up to 90 degrees without damaging them. It also has high thermal conductivity and electrical conductivity, and it shows the nature of conductors and semiconductors depending on the angle at which the carbon layer is wound. The average density of the sheet including the carbon nanotubes may vary depending on the ultrasonic treatment time within the range. When the ultrasonic treatment time is increased, the density is also increased. However, the density is not increased more than the predetermined treatment time. Graphite is a carbon isotope made of a hexagonal stable structure by firing carbon at high temperature (2,500 ° C to 3,000 ° C) for about two weeks under air-blocked conditions. Graphite is also a material suitable for precision machining because it has high thermal conductivity and electrical conductivity and is easy to process. Therefore, sheets containing carbon nanotubes and graphite, metal particles, or a combination thereof have flexibility and high thermal conductivity due to their inherent physical properties, resulting in excellent heat-radiating properties.

In one embodiment of the present invention, the weight ratio of the carbon nanotube to the graphite may be 50:50 to 5:95, but is not limited thereto. For example, the weight ratio of the carbon nanotube to the graphite may be 50:50, preferably 40:60, and more preferably 5:95, but is not limited thereto. The higher the graphite content, the more preferable .

In one embodiment of the present invention, the sheet may be a heat-radiating sheet, but is not limited thereto. Further, the "sheet" of the carbon nanotube / graphite hybrid heat radiation sheet, the carbon nanotube / metal particle hybrid heat radiation sheet or the carbon nanotube / graphite / metal particle hybrid heat radiation sheet manufactured through the vacuum filtration process is " But it is not limited to this.

In one embodiment of the present invention, a heat treatment process using a thermal furnace may be utilized to reduce the defects of the carbon nanotube-based heat radiation sheet, but the present invention is not limited thereto. The heat treatment process may be performed under a nitrogen atmosphere, for example, at a temperature of 800 to 2800 캜, 1300 to 2800 캜, 1800 캜 to 2800 캜, 2300 캜 to 2800 캜, 800 캜 to 2300 캜, 800 캜 to 1800 캜, Lt; 0 > C to 1300 < 0 > C for about 1 hour to 3 hours.

A laser flash method can be used to analyze the thermal conductivity of the hybrid heat-radiating sheet. The laser scintillation method is a method of heating the surface of a sample by irradiating a laser and recording the temperature of the back surface of the sample as a function of time to measure the thermal diffusivity. In-plane and through-plane thermal conductivity can be analyzed from room temperature to high temperature using laser flashing.

In one embodiment of the present invention, the carbon nanotubes may be one kind of sheet selected from the group consisting of single-walled carbon nanotubes, hydrophobic-walled carbon nanotubes, multi-walled carbon nanotubes, or combinations thereof. It is not. The carbon nanotubes may include single-walled carbon nanotubes (SWCNTs), single-walled carbon nanotubes (FWCNTs) having a number of carbon walls of 2 to 10, few-walled carbon nanotubes Walled carbon nanotubes (MWCNTs) in which a plurality of carbon nanotubes are concentrically formed, but the present invention is not limited thereto.

In one embodiment of the present invention, the metal particles are selected from the group consisting of Li, Be, B, Na, Mg, Al, P, S, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ba, La, Ce, Pr, Ba, Ba, Zn, Ga, Ge, As, Se, Rb, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Which is selected from Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, But the present invention is not limited thereto. Specifically, the metal particles may be selected from Sn, SnAgCu, organic Ag (organic silver), or a combination thereof. When the metal particles are thermally conductive particles and are combined with carbon nanotubes exhibiting high thermal conductivity to be used as a heat dissipator, the heat dissipation characteristics are improved and the heat dissipation member can be made smaller / lighter due to the reduction of the metal matrix content.

In one embodiment of the present invention, the content of the metal particles may be 1% to 50% of the weight of the carbon nanotubes, but is not limited thereto.

Another aspect of the present invention is to provide a thermosetting or PPS (polyphenylene sulfide (PPS)) resin such as epoxy or the like on a carbon nanotube / graphite hybrid heat radiation sheet, a carbon nanotube / metal particle hybrid heat radiation sheet or a carbon nanotube / graphite / ), PBT (polybutylene terephthalate), PC (polycarbonate) or the like are mixed to provide a carbon nanotube-based heat radiation sheet / polymer composite.

In one embodiment of the invention, the polymer may be any one selected from epoxy, polybutylene terephthalate, or combinations thereof, but is not limited thereto. The polybutylene terephthalate is represented by the following general formula (1), wherein n is an integer of 20 or more and can be obtained by heat-treating cyclic butylene terephthalate as shown in the following reaction formula (1).

[Reaction Scheme 1]

The carbon nanotubes may be single wall carbon nanotubes, small wall carbon nanotubes, or multi wall carbon nanotubes, but the present invention is not limited thereto.

Polymer composites using carbon nanotubes can be classified according to the formation method. Thin film complexes used in two-dimensional form such as transparent electrode and field emission electrode using thin film printing method, and three-dimensional form by extrusion and injection Bulk complexes. The composite using polymer and carbon nanotube is used as a transparent electrode and a field emission electrode in a thin film type, and can be applied to a bulk type as high strength, electrostatic discharge, antistatic, electromagnetic wave shielding, and high heat dissipation material.

According to another aspect of the present invention, there is provided a method of manufacturing a polymer composite including a step of preparing a carbon nanotube-based heat-radiating sheet through ultrasonic treatment and vacuum filtration, and a step of injecting a polymer component into a prepared heat- to provide.

The polymer may be a thermoplastic polymer or a thermosetting polymer, and the injected polymer component may be a monomer or a polymer of a thermoplastic or thermosetting polymer, but is not limited thereto.

The thermoplastic resin is a plastic or deformable polymer material which is melted as a liquid and can be re-melted and re-molded after curing. For example, the thermoplastic resin may be an acrylic resin, a vinyl chloride resin, a vinyl acetate resin, a vinyl acetyl resin, a methyl methacrylate resin, a styrene resin, a polycarbonate resin, a polyphenylene sulfide resin, a polypropylene resin, Polyamide resin (nylon), and the like may be used, but the present invention is not limited thereto.

A thermosetting resin is a polymeric material that is cured to a stronger form upon application of energy, and once cured it can not be heated or molded again. For example, the thermosetting resin may be a phenol resin, a urea resin, a melamine resin, an unsaturated polyester resin, an epoxy resin, a polyurethane resin, a polyamide resin, an alkyd resin, a silicone resin or a flan resin. But is not limited thereto.

Another aspect of the present application relates to a carbon nanotube comprising 1 wt% to 50 wt% of carbon nanotubes, 1 wt% to 95 wt% of any one of graphite, metal particles, or combinations thereof, and epoxy, polybutylene terephthalate, By weight of the total weight of the polymer composite.

Preferred embodiments of the polymer composite including the flexible carbon nanotube / graphite hybrid heat-radiating sheet of the present invention, the carbon nanotube / metal particle hybrid heat-radiating sheet, and the carbon nanotube-based heat-radiating sheet and the method of manufacturing the same are shown in the accompanying drawings Will be described in detail with reference to FIG.

However, the following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

Example 1: Production of carbon nanotube / graphite hybrid heat-radiating sheet

(CNT: graphite = 40:60, 10:90) of carbon nanotubes (CNT) and graphite (size: 300 μm) were added to 500 ml of ethanol to prepare a hybrid heat radiation sheet. The mixture was agitated for 1 hour using a stirrer so that the carbon nanotubes and the graphite were mixed well, and then ultrasonicated for 4 hours using a bath-type sonicator. After completion of the ultrasonic treatment, the mixture was stirred for 1 hour using a stirrer, filtered through a vacuum filtration apparatus, and then completely evaporated using a hot air drier (100 ° C) to prepare a heat-radiating sheet.

Example 2: Production of carbon nanotube / Sn hybrid heat-radiating sheet

10 mg of Sn was added to 500 ml of ethanol and sonicated for 1 hour using a horn-type sonicator. Then, the mixture was agitated for 1 hour using a stirrer so that the carbon nanotubes and Sn were mixed well, and then ultrasonicated for 4 hours using a bath-type sonicator. After completion of the ultrasonic treatment, the mixture was stirred for 1 hour using a stirrer, filtered through a vacuum filtration apparatus, and then completely evaporated using a hot air drier (100 ° C) to prepare a heat-radiating sheet. The heat-radiating sheet was heat-treated at 300 DEG C for 1 hour in a nitrogen atmosphere using an electric furnace.

Example 3: Production of carbon nanotube / SnAgCu hybrid heat-radiating sheet

10 mg of SnAgCu was added to 500 ml of ethanol and sonicated for 1 hour using a horn-type sonicator. Thereafter, the mixture was agitated for 1 hour using a stirrer so that the carbon nanotubes and SnAgCu were mixed well, and then ultrasonicated for 4 hours using a bath-type sonicator. After completion of the ultrasonic treatment, the mixture was stirred for 1 hour using a stirrer, filtered through a vacuum filtration apparatus, and then completely evaporated using a hot air drier (100 ° C) to prepare a heat-radiating sheet. The heat-radiating sheet was heat-treated at 300 DEG C for 1 hour in a nitrogen atmosphere using an electric furnace.

Example 4: Production of carbon nanotube / organic Ag (organic silver) hybrid heat radiation sheet

The organic Ag used was a 5% dispersion of Ag (5 nm or less in diameter) in methanol (Ditto Technology, Ditto Technology). To 500 ml of ethanol, 10 mg of organic Ag dispersed in methanol was added and sonicated for 1 hour using a horn-type sonicator. Then, the mixture was agitated for 1 hour using a stirrer so that the carbon nanotubes and Organic Ag were mixed well, and then ultrasonicated for 4 hours using a bath-type sonicator. After completion of the ultrasonic treatment, the mixture was stirred for 1 hour using a stirrer, filtered through a vacuum filtration apparatus, and then completely evaporated using a hot air drier (100 ° C) to prepare a heat-radiating sheet. The heat-radiating sheet was heat-treated at 300 DEG C for 1 hour in a nitrogen atmosphere using an electric furnace.

Example 5: Preparation of a polymer (epoxy) composite including a carbon nanotube / graphite hybrid heat-radiating sheet

An epoxy solution was poured onto a carbon nanotube / graphite (carbon nanotube: graphite weight ratio = 10: 90) hybrid heat radiation sheet prepared in the same manner as in Example 1, filtered using a vacuum filtration apparatus, And then cured at 175 ° C for 4 hours to prepare a composite of a carbon nanotube / graphite hybrid heat-radiating sheet and a polymer (epoxy).

Example 6: Production of polymer (epoxy) composite including carbon nanotube / Sn hybrid heat-radiating sheet

The epoxy solution was poured onto a carbon nanotube / Sn (diameter: 20 to 40 nm) hybrid heat-radiating sheet prepared in the same manner as in Example 2, filtered through a vacuum filtration apparatus, and dried at 175 ° C for 4 hours And a composite of a carbon nanotube / Sn hybrid heat-radiating sheet and a polymer (epoxy) was produced through a curing process.

Example 7: Production of polymer (epoxy) composite including carbon nanotube / organic Ag (organic silver) hybrid heat-radiating sheet

An epoxy solution was poured onto the carbon nanotube / organic Ag hybrid heat-radiating sheet prepared in the same manner as in Example 4, filtered through a vacuum filtration apparatus, cured at 175 ° C for 4 hours using a dryer, Composite of nanotube / organic Ag hybrid heat-radiating sheet and polymer (epoxy) was prepared.

Example 8: Preparation of carbon nanotube / graphite-containing polymer (polybutylene terephthalate: PBT) composite

Carbon nanotubes, graphite, and CBT were prepared in a weight ratio of 5:45:50. First, the prepared carbon nanotubes and graphite were added to 500 ml of ethanol, and stirred for 1 hour using a stirrer to mix them well. Subsequently, the agitated solution was sonicated for 2 hours using a horn-type sonicator. Then CBT was added and stirred for 1 hour using a stirrer to mix well. Subsequently, ultrasonic treatment was performed using a horn-type sonicator for 2 hours, stirring was performed for 1 hour, and filtration was performed using a vacuum filtration apparatus. The solvent was completely evaporated using a hot-air dryer (100 ° C) to prepare a heat-radiating sheet. The heat-radiating sheet was heat-treated at 250 ° C for 3 minutes using a hot-press to prepare a carbon nanotube / graphite-containing polymer (PBT) composite for heat dissipation material.

Comparative Example 1: Production of a carbon nanotube / graphite-containing polymer (polybutylene terephthalate: PBT) composite

The materials were ball-milled for 3 hours at 300 rpm for one hour at a weight ratio of MWCNT, MWCNT, graphite, and CBT of 5:45:50, and hot press ) For 3 minutes at 250 ° C to prepare a thin film of carbon nanotube / graphite-containing polymer (PBT) composite for heat dissipation material.

Comparative Example 2: Preparation of carbon nanotube / graphite-containing polymer (polybutylene terephthalate: PBT) composite

A carbon nanotube / graphite (carbon nanotube: graphite weight ratio = 10: 90) hybrid heat-radiating sheet prepared in the same manner as in Example 1 was placed on CBT powder, and CBT powder was further added thereto. Thereafter, heat treatment was performed at 250 ° C for 3 minutes using a hot-press to prepare a carbon nanotube / graphite-containing polymer (PBT) composite for heat dissipation material.

2 is a scanning electron microscope (SEM) image according to a graphite ratio of a carbon nanotube / graphite hybrid heat-radiating sheet manufactured according to Example 1. Fig. The ratio of carbon nanotubes to graphite is 40:60 and 10:90, and graphite which is more clearly observed on the surface of the carbon nanotube / graphite heat-radiating sheet when 90 wt% of graphite is contained can be confirmed.

FIG. 3 shows the results of thermal conductivity according to the graphite ratio of the carbon nanotube / graphite hybrid heat-radiating sheet. It has been shown that the thermal conductivity of carbon nanotube / graphite hybrid heat-radiating sheet is improved when at least 50 wt% or more of graphite is contained. The average thermal conductivity when the graphite was contained at 60 wt% was about 5 W / mK, which was somewhat better than the average thermal conductivity at the time when the graphite was not contained at all, which was about 3.6 W / mK. When the graphite was 90 wt% The average heat conductance is about 7.5 W / mK, which is about twice the improvement.

4 is a process flow chart of the second to fourth embodiments. A method for producing a carbon nanotube / metal particle hybrid heat-radiating sheet by mixing carbon nanotubes and metal particles was prepared by dispersing metal particles in ethanol and then mixing them with carbon nanotubes.

FIG. 5 is a SEM image of a carbon nanotube / Sn metal particle hybrid heat-radiating sheet manufactured according to Example 2. FIG. SEM images were used to identify Sn adsorbed on carbon nanotubes. The average thermal conductivity of the carbon nanotube / Sn metal particle hybrid heat-radiating sheet was about 4.5 W / mK.

6 is a SEM image of a carbon nanotube / SnAgCu metal particle hybrid heat-radiating sheet manufactured in Example 3. Fig. The SnAgCu adsorbed on the carbon nanotubes as a whole can be confirmed by SEM image and the alloyed form can be observed by using the scale bar 30 ㎛.

7 is a SEM image of the carbon nanotube / organic Ag hybrid heat-radiating sheet produced in Example 4. Fig. It was confirmed that fine particles of organic Ag were evenly adsorbed on the carbon nanotube sheet.

8 is a process flow chart of the eighth embodiment. In a method for producing a composite of carbon nanotube, graphite, and polymer (PBT), the carbon nanotube-based polymer (PBT) complex according to the present invention uses a uniform and dense carbon nanotube and graphite mixed solution produced through ultrasonic treatment . By mixing the carbon nanotubes and the graphite, ultrasonic treatment enhances the interfacial contact between the two materials to increase the density, thereby preventing the thermal conductivity from decreasing due to interfacial pores. The carbon nanotube and graphite mixed solution was mixed with CBT capable of polymerization by heat treatment to prepare a polymer composite material having improved thermal conductivity. The measured average thermal conductivity was about 10.87 W / mK, Which is significantly improved compared to the average thermal conductivity of the composite of about 6.7 W / mK.

9 is a process flow chart of Comparative Example 1. Fig. Carbon nanotubes, graphite, and CBT were ball milled (300 rpm, 3 hours) at one time, heat treated (250 ° C, 3 minutes), and ultrasound No treatment was done. The measured average thermal conductivity of the carbon nanotube / graphite-containing polymer (PBT) composite prepared according to Comparative Example 1 was about 6.7 W / mK.

10 is a SEM image of the prepared carbon nanotube / graphite-containing polymer (PBT) composite. As shown in Fig. 10, a form in which carbon nanotubes and graphite were dispersed in a polymer (PBT) was observed.

It will be understood by those skilled in the art that the foregoing description of the embodiments is for illustrative purposes and that those skilled in the art can easily modify the invention without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention .

Claims (11)

A carbon nanotube sheet having a thermal conductivity of 2.5 to 9 W / mK and containing no carbon nanotubes and one selected from the group consisting of graphite, metal particles, or a combination thereof; The method according to claim 1,
Wherein the weight ratio of the carbon nanotubes to the graphite is 50:50 to 5:95. The method according to claim 1,
Wherein the sheet is a heat radiation sheet. The method according to claim 1,
Wherein the carbon nanotubes are selected from the group consisting of single wall carbon nanotubes, hydrophobic wall carbon nanotubes, multiwall carbon nanotubes, or combinations thereof. The method according to claim 1,
The metal particles may be selected from the group consisting of Li, Be, B, Na, Mg, Al, P, S, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Containing at least one element selected from among Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tube sheet. 6. The method of claim 5,
Wherein the metal particles are any one selected from Sn, SnAgCu, organic silver, or a combination thereof. The method according to claim 1,
Wherein the content of the metal particles is 1% to 50% of the weight of the carbon nanotubes. A polymer composite comprising the carbon nanotube sheet of claim 1. 9. The method of claim 8,
Wherein the polymer is any one selected from the group consisting of epoxy, polybutylene terephthalate, and combinations thereof. A first step of preparing the carbon nanotube sheet of claim 1 through ultrasound treatment and vacuum filtration; And
And a second step of injecting a polymer component into the carbon nanotube sheet prepared in the first step. 1 wt% to 50 wt% of carbon nanotubes, 1 wt% to 95 wt% of any one of graphite, metal particles, or a combination thereof, and epoxy, polybutylene terephthalate, By weight to 95% by weight.

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