KR20110123457A - Thermal diffusion seat - Google Patents

Abstract

PURPOSE: A thermal spread-sheet is provided to guarantee horizontal heat conduction as a sheet consisting of graphite and to reduce costs by coating a copper or aluminum sheet by a [carbon nano tube having a constant thickness. CONSTITUTION: A carbon nano tube(300) is formed in one side of a copper sheet(100) or an aluminum sheet(200). Adhesive(400) is formed in the other side of the copper sheet or the aluminum sheet. The copper sheet or the aluminum sheet in which the carbon nano tube is formed is laminated. A PET film(500) is formed in the top part of the sheet which is laminated. An acryl double coated adhesive tape(600) is formed in the lowest area. A clad sheet in which the aluminum sheet is rolled is formed between the copper sheets. The thickness of the copper sheet or the aluminum sheet is from 9 to 100μm.

Description

Thermal diffusion seat {Thermal diffusion seat}

The present invention relates to a heat spreading sheet, and more particularly, to a heat spreading sheet capable of dissipating heat by forming a sheet in which carbon nanotubes are variously combined with heat generated from a heat source by coating carbon nanotubes with copper or aluminum.

In general, the heat diffusion sheet is a sheet that serves to effectively absorb heat generated from a heat source such as an electronic product and to quickly move heat to the outside.

Electronic and electronic components are becoming smaller and smaller, and as electronic devices become more advanced, very high temperatures occur in optical devices that require high power and control circuits that require fast processing speeds. This internal heat damages the electronic circuitry, resulting in shortened component life and malfunction of the device.

Therefore, conventionally, copper (heat conductivity 390 K / mk), aluminum (heat conductivity 240 K / mk) and the like which have excellent thermal conductivity have been used as a method for efficiently removing heat.

However, the copper and aluminum sheets have excellent thermal conductivity due to the isotropic thermal conductivity, but have a problem in that effective thermal conductivity cannot be obtained in the horizontal direction.

In recent years, heat diffusion sheets having high horizontal thermal conductivity are required in order to achieve rapid thermal conduction as electronic products become thinner. Accordingly, graphite (heat conductivity 350 to 400 K / mk) sheet having excellent thermal conductivity in the horizontal direction is used.

In addition, in the process of manufacturing a heat diffusion sheet using graphite sheets, the cutting surface is not clean when cutting graphite having graphite properties, and defects are generated. There have been problems.

The present invention has been made to solve the above problems, and has an object to provide a heat diffusion sheet having a lower manufacturing cost than a sheet made of graphite while having a superior effect of thermal conductivity in the horizontal direction.

Another object of the present invention is to provide a heat diffusion sheet having a low defect rate in the cutting process and hardly generating dust.

In order to achieve the above object, the present invention provides a carbon nanotube on one side of a copper sheet or an aluminum sheet, and an adhesive is formed on the other side to form a copper sheet or an aluminum sheet on which the carbon nanotubes are formed. A PET film is formed at the top, and an acrylic double-sided adhesive tape is formed at the bottom.

Then, an adhesive is formed on the copper sheet or the aluminum sheet to be laminated, and carbon nanotubes are formed on both sides of the laminated sheet, and a PET film is formed on the top of the laminated sheet on which carbon nanotubes are formed on both sides, and on the bottom, both sides of acrylic The adhesive tape is formed.

In addition, a clad sheet of aluminum sheet rolled between the copper sheet is formed, carbon nanotubes are formed on both sides of the clad sheet, a PET film is formed on the top of the clad sheet, and an acrylic double-sided adhesive tape is formed on the bottom of the clad sheet. It is done.

A plurality of aluminum sheets are rolled to form a stacked sheet, and carbon nanotubes are formed on both sides of the stacked sheets. A PET film is formed on the top of the stacked sheets, and an acrylic double-sided adhesive tape is formed on the bottom thereof. Characterized in that formed.

Here, the thickness of the said copper sheet or an aluminum sheet is 9-100 micrometers, The heat diffusion sheet characterized by the above-mentioned.

Here, the aluminum sheet has a thickness of 9 to 100 µm.

Here, the total thickness of the heat diffusion sheet made of the copper sheet or the aluminum sheet is characterized in that the thickness of 50 ~ 600㎛.

Here, the carbon nanotubes are carbon nanotubes having a multi-wall structure, and are characterized by having a thickness of 0.1 to 20 μm.

Here, the number of the copper sheet or the aluminum sheet is laminated is characterized in that 2 to 10.

Here, the adhesive is characterized in that the thickness of 2 ~ 20㎛.

According to the present invention of the configuration described above, the following effects can be expected.

First, a sheet made by coating carbon nanotubes having high thermal conductivity in the vertical direction and having high thermal conductivity in the horizontal direction with a low thermal copper sheet in the vertical direction is assured that the thermal conductivity is as horizontal as a sheet made of graphite. Coating carbon nanotubes of a certain thickness has the advantage of obtaining a heat diffusion sheet that is cheaper than the graphite sheet.

In addition, the sheet coated with carbon nanotubes on copper or aluminum has a constant cutting surface when cutting during manufacturing, resulting in less defects, and less dust, which improves the working environment and reduces worker health and environmental pollution. There will also be effects.

1 is a cross-sectional view of a heat diffusion sheet according to a preferred embodiment of the present invention.
2 (a) and 2 (b) are cross-sectional views of a heat diffusion sheet according to a second preferred embodiment of the present invention.
3 is a cross-sectional view of a heat diffusion sheet according to a third preferred embodiment of the present invention.
4 is a cross-sectional view of a heat diffusion sheet according to a fourth preferred embodiment of the present invention.
5 is an exemplary test apparatus for testing various experimental examples.
Table 1 is an experimental result table according to FIG.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a cross-sectional view of a heat diffusion sheet according to a preferred embodiment of the present invention.

As shown in the present invention, the copper sheet 100, aluminum sheet 200, carbon nanotubes 300, adhesive 400, PET film 500 and acrylic double-coated adhesive tape 600, A feature of the present invention is a structure in which the carbon nanotubes 300 are formed and stacked on one side of the copper sheet 100 or the aluminum sheet 200.

First, the copper sheet 100 or the aluminum sheet 200 in the form of a thin plate is formed by coating the carbon nanotubes 300, the other side is formed of the copper sheet 100 or aluminum sheet coated with the carbon nanotubes 300 Adhesive 400 is formed so that the 200 is stacked, the PET film 500 is formed on the top of the laminated sheet, and the acrylic double-sided adhesive tape 600 is formed on the bottom to produce a heat diffusion sheet.

Here, the copper sheet 100 and the aluminum sheet 200 on which the carbon nanotubes 300 are formed may be sequentially stacked, or the copper sheet 100 or the aluminum sheet 200 may be stacked. .

Meanwhile, the reason why the carbon nanotube 300 having high horizontal thermal conductivity is coated on the copper sheet 100 or the aluminum sheet 200 is that the carbon nanotube 300 is in the form of a powder, and thus is manufactured as a heat diffusion sheet. Because it can not be.

In addition, considering that the carbon nanotubes 300 are also expensive, the carbon nanotubes 300 are mixed with the relatively inexpensive copper sheet 100 or the aluminum sheet 200.

In the following, the carbon nanotubes 300 may be understood in consideration of the difficulty of being used alone.

And, the thickness of the copper sheet 100 or aluminum sheet 200 is to be 9 ~ 100㎛.

The carbon nanotube 300 is referred to in English abbreviation CNT (Carbon nanotube), is a honeycomb-shaped long carbon structure is used as a semiconductor material with excellent electrical and mechanical properties, and the thermal conductivity is 6000W / mK copper 390W / mK And aluminum has better properties than 240W / mK.

Here, the carbon nanotube 300 is made of a single-wall, double-wall, multi-wall by using a gas containing carbon and synthesized, in the present invention is a carbon nanotube of a multi-wall structure, the copper sheet 100 or On one side of the aluminum sheet 200 is preferably coated with a thickness of 0.1㎛ ~ 20㎛.

The adhesive 400 is to be laminated to the copper sheet 100 or aluminum sheet 200 coated with the carbon nanotubes 300 polyurethane (polyurethane), epoxy polyester (epoxy polyester), hot melt adhesive (hotmelt adhesive) and the like and are preferably used in consideration of heat resistance and metal adhesion.

Here, the adhesive 400 is characterized in that the thickness of 2 ~ 20㎛.

On the other hand, the number of the copper sheet 100 or the aluminum sheet 200 is stacked is preferably 2 to 10.

The PET film 500 is polyethylene terephthalate (PET) and an acrylic adhesive is preferably applied to the lower side of the PET film 500 so as to be formed on the top of the laminated sheet.

Here, the thickness of the PET film 500 is 12 ~ 38㎛, the thickness of the acrylic adhesive is to be 10 ~ 30㎛.

The acrylic double-sided adhesive tape 600 is an acrylic pressure-sensitive adhesive is formed on both sides of the polyethylene terephthalate (PET, PolyEthylene Terephtalate) like the PET film 500.

Here, the thickness of the PET film 500 formed on the acrylic double-coated adhesive tape 600 is to be 12 ~ 38㎛, the thickness of the acrylic adhesive is preferably 10 ~ 30㎛. The reason is that the acrylic double-coated adhesive tape 600 is a step in which heat conduction starts from an external heat source. When the thickness of the PET film 500 exceeds 38 μm, heat transfer from the heat source is insufficient, and the acrylic adhesive has a thickness of 10 μm. If it is less than this, the adhesive force is insufficient and a problem arises in surface adhesion.

In addition, a thermally conductive filler is added to the acrylic adhesive to increase thermal conductivity. The fillers include carbon nanotubes (CNT), boron nitride (BN), and aluminum nitride (ALN) metal oxides. The above fillers may be mixed and used, but the present invention is not limited thereto.

On the other hand, the total thickness of the heat diffusion sheet made of the copper sheet 100 or the aluminum sheet 200 is to be 50 ~ 600㎛ thickness.

In this way, as described above, the carbon nanotube 300 having excellent thermal conductivity in the horizontal direction is coated on the copper sheet 100 or the aluminum sheet 200 which is excellent in the vertical direction and inexpensive in the thickness direction. It is possible to produce heat diffusion sheets that are as good as graphite sheets but at a lower cost.

2 (a) and 2 (b) show cross-sectional views of a heat diffusion sheet according to a second preferred embodiment of the present invention.

In the second preferred embodiment, the carbon nanotubes 300 are formed on both sides of the stacked sheets by laminating the copper sheet 100 or the aluminum sheet 200, respectively.

2, the adhesive 400 is formed on the copper sheet 100 or the aluminum sheet 200 in the form of a thin plate, and the carbon nanotubes 300 are formed on both sides of the stacked sheets, and carbon nanoparticles are formed on both sides. It can be seen that the PET film 500 is formed at the top of the laminated sheet on which the tube 300 is formed, and the acrylic double-sided adhesive tape 600 is formed at the bottom thereof.

Here, the copper sheet 100, the aluminum sheet 200, the carbon nanotubes 300, the adhesive 400, the PET film 500 and the acrylic double-sided adhesive tape 600 are the same as the first embodiment and will be described below Omit.

3 is a cross-sectional view of a heat diffusion sheet according to a third preferred embodiment of the present invention.

In a preferred embodiment, the clad sheet 700 having the aluminum sheet 200 formed therebetween is formed between the copper sheets 100, and the clad sheet 700 is laminated as necessary, so that the clad sheet 700 is double-sided or laminated. It is characterized in that the carbon nanotubes 300 are formed on both sides.

Referring to FIG. 3, a clad sheet 700 on which an aluminum sheet 200 is rolled is formed between thin copper sheets 100, and carbon nanotubes 300 are formed on both sides of the clad sheet 700. The uppermost part of the clad sheet 700 may be a PET film 500, and the lowermost part may be formed of an acrylic double-sided adhesive tape 600.

Here, the copper sheet 100, the aluminum sheet 200, the carbon nanotube 300, the PET film 500 and the acrylic double-sided adhesive tape 600 are the same as the first embodiment and will be omitted below.

4 is a cross-sectional view of a heat diffusion sheet according to a fourth preferred embodiment of the present invention.

In the fourth preferred embodiment, the carbon nanotubes 300 are formed on both sides by forming sheets of the aluminum sheet 200, which is a lightweight material, by rolling instead of an adhesive.

Referring to FIG. 4, a plurality of aluminum sheets 200, which are in a thin plate form, are rolled to form stacked sheets, and carbon nanotubes 300 are formed on both sides of the stacked sheets, and the uppermost portion of the stacked sheets is formed. It can be seen that the PET film 500 is formed, and the acrylic double-sided adhesive tape 600 is formed at the bottom.

Here, the aluminum sheet 200, the carbon nanotubes 300, the PET film 500 and the acrylic double-sided adhesive tape 600 is the same as the first embodiment and will be omitted below.

And, the thickness of the aluminum sheet 200 is characterized in that 9㎛ ~ 100㎛ thickness.

In addition, the total thickness of the heat diffusion sheet produced according to the above preferred embodiments 1,2,3 and 4 is to be 50 ~ 600㎛.

The following is an experimental example which produced the heat diffusion sheet which is this invention variously.

Experimental Example 1

a. 5㎛ coated carbon nanotubes on a 30㎛ aluminum sheet.

b. 5㎛ coated carbon nanotubes on a 19㎛ aluminum sheet.

c. After laminating a and b in four layers alternately using a polyurethane adhesive, a PET film was attached to the top and an acrylic double-sided adhesive tape was attached to the bottom to complete the heat diffusion sheet.

Experimental Example 2

a. Four layers were laminated on a 30 μm aluminum sheet using a polyurethane adhesive.

b. On both sides of the laminated aluminum sheet is coated with carbon nanotubes 5㎛ thick.

c. A PET film was attached to the top of the carbon nanotube-coated aluminum sheet and an acrylic double-sided adhesive tape was attached to the bottom to complete the heat diffusion sheet.

Experimental Example 3

a. It laminated | stacked 6 layers using the polyurethane adhesive on the 30 micrometer aluminum sheet.

b. On both sides of the laminated aluminum sheet is coated with carbon nanotubes 5㎛ thick.

c. A PET film was attached to the top of the carbon nanotube-coated aluminum sheet and an acrylic double-sided adhesive tape was attached to the bottom to complete the heat diffusion sheet.

Experimental Example 4

a. It was laminated in six layers using a polyurethane adhesive on a 19 μm copper sheet.

b. On both sides of the laminated aluminum sheet is coated with carbon nanotubes 5㎛ thick.

c. A PET film was attached to the top of the carbon nanotube-coated aluminum sheet and an acrylic double-sided adhesive tape was attached to the bottom to complete the heat diffusion sheet.

Experimental Example 5

a. Copper, aluminum and copper are sequentially coated on both sides of the carbon nanotubes having a thickness of 5 μm on both sides of a 50 μm thick rolled clad sheet.

b. A PET film was attached to the top of the carbon nanotube-coated clad sheet, and an acrylic double-sided adhesive tape was attached to the bottom of the clad sheet to complete the heat diffusion sheet.

<Experimental Example 6>

a. Roll 6 sheets of aluminum sheet having a thickness of 30 μm and coat both surfaces of the rolled metal with carbon nanotubes having a thickness of 5 μm.

b. A PET film was attached to the top of the carbon nanotube-coated aluminum sheet and an acrylic double-sided adhesive tape was attached to the bottom to complete the heat diffusion sheet.

Comparative Example 1

a. Natural graphite sheet with thermal conductivity of 350-400 W / mK

As described above, the thermal conductivity evaluation of the thermal diffusion sheet in each experimental example and the graphite sheet in Comparative Example 1 was performed as shown in Figure 5 and the results are shown in Table 1.

First of all, width 100mm. A thermal diffusion sheet of each experimental example having a length of 180 mm was prepared and a sheet of Comparative Example 1 was prepared. As shown in FIG. 5, a heating element was prepared using a cylindrical cartridge heater 11. An aluminum sheet 33 having a thickness of 1T was placed on the cartridge heat and prepared by attaching specimens 22 of Experimental Example 1 and Comparative Example 1 thereon. The point just above the specimen 22 was called SP1, and the point 7 cm away from SP1 was called SP2.

Then, the temperature of the SP1 point and the SP2 point after 5 minutes, 10 minutes, 15 minutes, and 20 minutes after the cartridge heater 11 with the temperature controller was heated was measured.

The thermal diffusivity is shown in Table 1 as the temperature difference of SP2 point 7 cm away from the exothermic point SP1, and the measurement equipment was measured using a ThermaCAM P25 thermal imaging camera.

In Table 1 blank, each experimental example and Comparative Example 1 showed the heat diffusion characteristics.

The blank was tested by attaching electrical insulating tape on a 1 mm thick aluminum sheet.

In the blank, the thermal diffusion from the SP1 point to the SP2 point showed a temperature difference of 12.8 ° C. at a distance of 7 cm. The test results of each Experimental Example and Comparative Example 1 on the basis of the temperature difference is as follows.

5 minutes later (℃) 10 minutes later (℃) 15 minutes later (℃) After 20 minutes (℃) Heat diffusion (△ T) SP1 SP2 SP1 SP2 SP1 SP2 SP1 SP2 SP1-SP2
(After 20 minutes) blank 48.7 37.1 59.8 47.4 61.6 49.0 63.9 51.5 12.8 Experimental Example 1 50.5 41.6 59.9 50.7 62.8 54.0 62.0 52.5 9.5 Experimental Example 2 48.4 39.7 60.0 50.4 62.1 52.8 64.3 54.5 9.8 Experimental Example 3 48.4 40.3 59.2 50.7 62.0 53.5 62.9 54.6 8.4 Experimental Example 4 48.1 43.3 55.6 49.5 62.1 55.7 62.8 55.8 7.0 Experimental Example 5 50.1 41.2 57.7 50.5 62.3 51.8 62.2 52.5 9.7 Experimental Example 6 49.3 42.5 57.4 49.3 60.7 52.5 62.1 53.2 8.9 Comparative Example 1 49.7 40.8 58.6 49.2 62.3 52.6 60.6 51.2 9.4

First, the 4-ply sheet in which aluminum and copper were laminated in Experimental Example 1 and the sheet laminated only by 4-ply of aluminum in Experimental Example 2 and the heat diffusion characteristics did not change significantly. Compared with the blank, the temperature difference of 3 ~ 3.3 ℃ is shown, and when the number of aluminum laminates in Experimental Example 3 is increased to six layers, the thermal diffusion (△ T) occurs a temperature difference of 4.4 ℃ compared to the blank, so the number of aluminum laminates is increased. As can be seen that the heat is effectively diffused from the heating element.

In Experimental Example 4, as a result of six layers of copper sheets having a thickness of 19 μm, a very excellent heat diffusion result was obtained at a temperature difference of 5 ° C. or more when compared to the blank.

Next, in Experimental Example 5 and Experimental Example 6, as a result of the experiment using the rolled clad sheet, the results similar to those of Experimental Example 1 and Experimental Example 2 were obtained. there was.

Analyzing the above experimental results, it can be seen that the thermal diffusion property increases when the number of laminated copper or aluminum sheets is increased with an adhesive or the number of laminated films is increased by rolling.

Comparative Example 1 is a natural graphite sheet having a horizontal heat dissipation degree of 400 W / mK and heat diffusion (ΔT) after 20 minutes showed a temperature difference of 3.4 ℃ compared to the blank.

As a result of each experimental example, even when compared with the natural graphite sheet of Comparative Example 1, which is widely used for horizontal heat dissipation, the horizontal heat diffusion effect is similar, or in Experimental Examples 3 and 4, excellent results were obtained.

Accordingly, this Experimental Example is not limited to the above Experimental Example and may be modified within the scope of the appended claims and equivalents.

According to the present invention, a heat diffusion sheet is constructed using carbon nanotubes, and it is difficult to construct a heat diffusion sheet using carbon nanotubes, and it is difficult to utilize them because it is expensive, such as graphite, but inexpensive copper or aluminum. Since carbon nanotubes with excellent horizontal thermal conductivity can be easily coated to provide various combination sheets, it is possible to replace graphite's horizontal thermal conductivity and provide an inexpensive thermal diffusion sheet, which is useful in industrial sites. There is an advantage that can be widely used.

As described above, the present invention shows a thermal conductivity effect by coating a carbon nanotube having excellent thermal conductivity in a horizontal direction on a copper or aluminum sheet having excellent thermal conductivity in a vertical direction, as well as a graphite sheet exhibiting excellent horizontal thermal conductivity, and is coated with carbon nanotubes. Alternatively, it can be seen that it is a basic technical idea to provide a heat diffusion sheet that satisfies a heat diffusion standard by selectively laminating an aluminum sheet, and to provide a heat diffusion sheet that is cheaper than a graphite sheet. Within the scope, many other variations are possible to those of ordinary skill in the art.

100: copper sheet 200: aluminum sheet
300: carbon nanotube 400: adhesive
500: PET film 600: acrylic double-coated adhesive tape
700: clad sheet

Claims (10)

The carbon sheet 100 is formed on one side of the copper sheet 100 or the aluminum sheet 200, and the adhesive 400 is formed on the other side to stack the copper sheet or the aluminum sheet on which the carbon nanotubes are formed. PET film 500 is formed on the top of the heat diffusion sheet, characterized in that the acrylic double-sided adhesive tape 600 is formed on the bottom. Adhesive 400 is formed and laminated on the copper sheet 100 or the aluminum sheet 200, and carbon nanotubes 300 are formed on both sides of the stacked sheets, and carbon nanotubes are formed on both sides. PET film 500 is formed, the bottom of the heat diffusion sheet, characterized in that the acrylic double-coated adhesive tape 600 is formed. A clad sheet 700 is formed between the copper sheet 100 and the aluminum sheet 200 is rolled, and carbon nanotubes 300 are formed on both sides of the clad sheet 700, and the top of the clad sheet 700 is formed. PET film 500 is formed, the bottom of the heat diffusion sheet, characterized in that the acrylic double-coated adhesive tape 600 is formed. A plurality of aluminum sheets 200 are rolled to form a stacked sheet, carbon nanotubes 300 are formed on both sides of the stacked sheets, and the PET film 500 is formed on the top of the stacked sheets. And, the bottom of the heat diffusion sheet, characterized in that the acrylic double-coated adhesive tape 600 is formed. The method of claim 1 or 3,
The thickness of the copper sheet 100 or aluminum sheet 200,
Heat diffusion sheet, characterized in that 9 to 100㎛. The method of claim 4, wherein
The thickness of the aluminum sheet 200,
Heat diffusion sheet, characterized in that 9 to 100㎛ thickness. 5. The method according to any one of claims 1 to 4,
The total thickness of the heat diffusion sheet made of the copper sheet 100 or the aluminum sheet 200,
Heat diffusion sheet, characterized in that 50 ~ 600㎛ thickness. 5. The method according to any one of claims 1 to 4,
The carbon nanotubes 300,
A carbon nanotube having a multi-wall structure and having a thickness of 0.1 to 20 μm. The method according to any one of claims 1 to 3,
The number of the copper sheet 100 or the aluminum sheet 200 is stacked,
Heat diffusion sheet, characterized in that 2 to 10. 3. The method according to claim 1 or 2,
The adhesive 400,
A heat diffusion sheet having a thickness of 2 to 20 µm.

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