Manufacturing method of graphite heat dissipation sheet

Abstract

The method for manufacturing the graphite heat dissipation sheet of the present invention includes the following steps: a first step of placing a graphite sheet (110) of a certain width between a pair of protective films (120), each having a heat-sealing layer (121) on its inner surface, and heat-sealing both sides of the pair of protective films (120) to seal both sides of the graphite sheet (110); a second step of evacuating the inside of the graphite sheet (110) with both sides sealed, heat-sealing the openings of the pair of protective films (120) to completely seal the graphite sheet (110), and applying heat to the surfaces of the pair of protective films (120) to heat-seal the surfaces of the graphite sheet (110); and a third step of cutting the edge portions of the graphite sheet (110).

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a graphite heat-dissipating sheet, and more particularly to a method for manufacturing a graphite heat-dissipating sheet, in which a graphite sheet is wrapped in a film or pouch having a heat-sealing layer on the inside surface, the interior is evacuated to a vacuum to remove gas and moisture from the graphite sheet, and heat is applied to the heat-sealing layer, thereby producing a graphite heat-dissipating sheet in which the graphite sheet is further firmly integrated with the film or pouch due to the fusion effect between the graphite sheet and the surface of the film or pouch in a molten state and the pressure bonding effect caused by the pressure difference due to the vacuum. [Background technology]

[0002] In recent years, as electronic devices have rapidly become denser and thinner, the performance of chips installed in the devices has improved, and this trend is expanding beyond electrical / electronic devices to automobiles, medical devices, etc. As chips used in electronic devices are integrated at high density, more heat is generated, which can cause various problems such as reduced performance of the electronic devices, malfunction of peripheral elements, and deterioration of substrates.

[0003] In particular, electronic devices (such as TVs) that use LEDs and OLEDs require thinner heat dissipation materials, and for this reason, the board on which the IC chip is mounted is manufactured using a metal printed circuit board (PCB) with good thermal conductivity, or a heat sink such as aluminum is used to control the heat.In addition, thermally conductive thin films such as natural graphite thin films and artificial graphite thin films using carbon-based materials, and copper foil are mainly used to control the heat in electronic devices.

[0004] On the other hand, heat dissipation sheets using natural graphite and / or artificial graphite can be constructed as thin films and have excellent heat dissipation performance. They can also be easily attached to heat-generating parts of electronic devices (such as TVs), so much research and development is being conducted on these.

[0005] The graphite heat dissipation sheet is generally manufactured by rolling expanded graphite particles into a sheet, which has drawbacks such as dust generation and brittleness. To overcome these structural drawbacks and to adhere to the target object, as disclosed in Patent Document 1, the sheet may be laminated with a protective film, followed by an adhesive layer and a release film to protect the adhesive layer. In this case, the protective film and the graphite sheet are bonded together using a hot melt or acrylic adhesive inserted between them.

[0006] However, graphite sheets have a layered structure due to rolling, which can cause residual gas and moisture to remain inside the sheet, which can lead to bubbles after lamination. Furthermore, if foreign matter is present on the surface of the graphite sheet during lamination, bubbles can form, and the adhesive strength between the protective films at the edges can be weak, leading to peeling. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Korean Patent No. 1509494 Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and its object is to provide a method for manufacturing a graphite heat-dissipating sheet, which comprises wrapping a graphite sheet in a film or pouch having a heat-sealing layer on the inside surface, evacuating the inside to remove gas and moisture from the graphite sheet, and applying heat to the heat-sealing layer, thereby producing a graphite heat-dissipating sheet in which the graphite sheet is more firmly integrated with the film or pouch due to the fusion effect between the graphite sheet and the surface of the film or pouch in a molten state and the pressure bonding effect caused by the pressure difference due to the vacuum. [Means for solving the problem]

[0009] To achieve the above object, the present invention provides a method for manufacturing a graphite heat dissipation sheet, comprising: a first step of placing a graphite sheet of a certain width between a pair of films, each having a thermoplastic heat-sealing layer on its inner surface that melts at a certain temperature, and heat-sealing both sides of the pair of films to seal both sides of the graphite sheet; a second step of evacuating the inside of the graphite sheet with both sides sealed, heat-sealing the openings of the pair of films to seal the entire graphite sheet, and applying heat to the surfaces of the pair of films to melt the heat-sealing layers, thereby heat-sealing the graphite sheet to the surfaces of the pair of protective films; and a third step of cutting the edges of the graphite sheet.

[0010] The first step may include the steps of: continuously supplying the pair of films by a film supply means; inserting the graphite sheet between the pair of films; heat-sealing both sides of the pair of films to seal both sides of the graphite sheet; and cutting the pair of films to a length sufficient to cover the graphite sheet.

[0011] In the second step, the graphite sheet with both sides sealed is preferably placed in a vacuum chamber, and after a certain period of vacuum decompression, the sheet is compressed with upper and lower heating members, so that the evacuation, the heat sealing of the opening, and the surface heat sealing are simultaneously performed in the vacuum chamber.

[0012] Meanwhile, the second step may include the steps of: placing the graphite sheet with both sides sealed into a vacuum chamber, vacuum-reducing the pressure for a certain period of time, and then heat-pressing the sheet to perform the evacuation and thermal sealing of the openings; and placing the sheet into a high-temperature chamber and heating the sheet to thermally seal the surfaces of the pair of films and the graphite sheet.

[0013] In order to achieve the above object, the present invention provides a method for manufacturing a graphite heat dissipation sheet, which includes the following steps: a first step of inserting a graphite sheet of a certain width into a film pouch having an open side and a thermoplastic heat-sealable layer on its inner surface that melts at a certain temperature; a second step of applying a vacuum to the open film pouch to evacuate the inside of the graphite sheet, heat-sealing the opening of the film pouch to seal the entire graphite sheet, and applying heat to the surface of the film pouch to melt the heat-sealable layer, thereby heat-sealing the graphite sheet to the surface of the film pouch; and a third step of cutting an edge portion of the graphite sheet.

[0014] In the second step, it is preferable that the film pouch with the graphite sheet disposed therein is placed in a vacuum chamber, and after evacuating for a certain period of time, the film pouch is compressed with upper and lower heating members, so that the evacuation, the heat sealing of the opening, and the surface heat sealing are performed simultaneously in the vacuum chamber.

[0015] Meanwhile, the second step may include the steps of: placing the film pouch with the graphite sheet disposed therein into a vacuum chamber, vacuum-reducing the pressure for a certain period of time, and then heat-pressing the film pouch to perform the evacuation and heat-sealing of the opening; and placing the film pouch into a high-temperature chamber and heating the film pouch to perform surface heat-sealing of the film pouch and the graphite sheet. [Effects of the Invention]

[0016] The present invention has the advantage that a graphite heat-dissipating sheet can be produced by wrapping a graphite sheet in a film or pouch having a heat-sealing layer on its inner surface, evacuating the interior to remove gas and moisture from the graphite sheet, and then applying heat to the heat-sealing layer, thereby achieving a fusion effect between the graphite sheet in a molten state and the surface of the film or pouch, and a pressure-bonding effect due to the pressure difference caused by the vacuum, thereby further solidly integrating the film or pouch and the graphite sheet. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram of a method for manufacturing a graphite heat dissipation sheet according to an embodiment of the present invention. [Figure 2] 2 is a cross-sectional view showing the structural relationship of a graphite heat dissipation sheet manufactured by the manufacturing method shown in FIG. 1. FIG. [Figure 3] 4 is a schematic diagram of a method for manufacturing a graphite heat dissipation sheet according to another embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, preferred embodiments of a method for manufacturing a graphite heat dissipation sheet according to the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the following embodiments, and may be embodied in various different forms. However, the present embodiments are provided so that the disclosure of the present invention will be complete and will fully convey the scope of the invention to those skilled in the art.

[0019] FIG. 1 is a schematic diagram of a method for manufacturing a graphite heat-dissipating sheet according to one embodiment of the present invention, and FIG. 2 is a cross-sectional view showing the structural relationship of the graphite heat-dissipating sheet manufactured by the manufacturing method shown in FIG.

[0020] As shown in FIGS. 1 and 2 , the method for manufacturing a graphite heat dissipation sheet of this embodiment includes the following steps: a first step of placing graphite sheet 110 of a certain width between a pair of protective films 120, each having a heat-sealing layer 121 on its inner surface, and heat-sealing both sides of pair of protective films 120 to seal both sides of graphite sheet 110; a second step of evacuating the inside of graphite sheet 110 with both sides sealed, heat-sealing the openings of pair of protective films 120 to seal the entire graphite sheet 110, and applying heat to the surfaces of pair of protective films 120 to heat-seal the surfaces to graphite sheet 110; and a third step of cutting the edge portions of graphite sheet 110.

[0021] The first step may include the steps of: continuously supplying a pair of protective films 120 from film supply roll 130 constituting a film supply means; inserting graphite sheet 110 between pair of protective films 120; heat-sealing both sides of pair of protective films 120 to seal both sides of graphite sheet 110; and cutting pair of protective films 120 to a length sufficient to cover graphite sheet 110.

[0022] The graphite sheet 110 is formed by compressing or rolling graphite powder to a certain thickness and width, and can be made of natural graphite, artificial graphite, or a mixture thereof. For example, the graphite sheet 110 of this embodiment can be made by mixing 80 to 95% by weight of natural graphite and 5 to 20% by weight of artificial graphite. The natural graphite is expanded graphite, which is obtained by crushing and powdering natural graphite, immersing it in sulfuric acid, neutralizing and washing it, and then expanding it by heating at high temperature. The natural graphite of this embodiment is a mixture of expanded graphite with diameters of 30 to 50 μm and 200 to 250 μm, respectively, in a certain ratio, and the artificial graphite can be made of graphite with a diameter of 20 to 80 μm.

[0023] That is, graphite sheet 110 of this embodiment can be made of natural graphite and / or artificial graphite having the above-mentioned properties (diameter, composition ratio), but it is not necessary to limit it to graphite with the above-mentioned specific properties. Also, graphite sheet 110 of this embodiment has a density of 0.8 to 1.65 g / cm 3 However, the density of the adhesive layer 11 is not limited to this.

[0024] Graphite sheet 110 contains fine gases in the graphite itself, and even if it is compressed or rolled to a certain density, it has a porous structure, so voids are formed, and these voids contain gases such as sulfuric acid gas generated during the manufacturing process of graphite sheet 110 and moisture from the atmosphere.

[0025] The protective film 120 is composed of a thermal seal layer 121 forming an inner surface and a protective layer 122 forming an outer surface. The thermal seal layer 121 may be made of polyethylene (PE), cold-bonded polypropylene (CPP), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), or the like, which has thermoplastic properties that melt at a certain temperature. The thickness of the thermal seal layer 121 is preferably less than 50 μm to minimize its influence on thermal diffusion performance. The protective layer 122 serves to protect the graphite sheet 110 located therein and may be made of polyethylene terephthalate (PET), nylon (Ny), ethylene vinyl alcohol (EVOH), or the like. The thickness of the protective layer 122 is preferably less than 20 μm to minimize its influence on thermal diffusion performance.

[0026] When performing the first step using the graphite sheet 110 and the pair of protective films 120, the pair of protective films 120 are continuously supplied using a pair of film supply rolls 130. Here, the film supply means and the pair of film supply rolls 130 may be configured in a configuration commonly used in the industry, and the pair of protective films 120 may be continuously supplied in a general manner. In this case, the pair of film supply rolls 130 supply the pair of protective films 120 while they are arranged vertically at a regular interval, thereby forming a space between the pair of protective films 120 into which the graphite sheet 110 can be inserted.

[0027] Thus, graphite sheet 110 is inserted into a space formed between a pair of supplied protective films 120 and disposed between the pair of protective films 120, and is held in close contact between the pair of protective films 120 by the pair of film supply rolls 130 and the pair of guide rolls 140 located at the rear end. Both sides of graphite sheet 110 are sealed by heat-sealing both sides of the pair of protective films 120 between the pair of film supply rolls 130 and the pair of guide rolls 140. Heat-sealing both sides of the pair of protective films 120 is performed by heating heat-sealing layers 121 constituting the inner surfaces of the pair of protective films 120 to bond them together, and a heating member (not shown) having a certain width may be used. Then, cutting member 150 located at the rear end of the pair of guide rolls 140 is used to cut the pair of protective films 120 to a length sufficient to cover graphite sheet 110, thereby sealing both sides with the pair of protective films 120 and completing graphite heat dissipation member 160 having openings 161 at the front, rear, or top and bottom.

[0028] The second step is a step of sealing all of graphite sheet 110 and heat-sealing the surfaces of a pair of protective films 120 and graphite sheet 110. Graphite heat dissipation member 160 is placed in vacuum chamber 170, and after vacuum decompression for a certain period of time, it is pressed with upper and lower heating members 180 to evacuate the inside of graphite heat dissipation member 160, and openings 161 of graphite heat dissipation member 160 are heat-sealed to join them, and the surfaces of a pair of protective films 120 and graphite sheet 110 are heat-sealed. All of these steps are performed at once within vacuum chamber 170.

[0029] Here, vacuum chamber 170 is a type commonly used in the industry and is configured to have a vacuum pressure sufficient to evacuate graphite heat dissipation member 160 and remove gas and moisture remaining inside graphite sheet 110. Upper and lower heating members 180 may each be a mold-type hot press that encases the upper and lower surfaces and edges of graphite heat dissipation member 160, heat-sealing opening 161 of graphite heat dissipation member 160 and joining the surfaces of pair of protective films 120 and graphite sheet 110 together. In this way, in the second step, heat is applied to heat-sealing layer 121 formed on the inner surface of protective film 120, thereby fusing graphite sheet 110 and the surfaces of pair of protective films 120 together in a molten state, and the pressure difference due to the vacuum creates a pressure-bonding effect, further solidifying pair of protective films 120 and graphite sheet 110 together.

[0030] Alternatively, the second step may involve first placing graphite heat dissipation member 160 into vacuum chamber 170, evacuating the interior of graphite heat dissipation member 160 by heat pressing after evacuating the interior of graphite heat dissipation member 160, and then heat-sealing and bonding openings 161 of graphite heat dissipation member 160. Then, the graphite heat dissipation member 160 may be placed in a high-temperature chamber at 110°C or higher and heated to heat-seal the surfaces of pair of protection films 120 and graphite sheet 110. Here, heat-sealing openings 161 of graphite heat dissipation member 160 involves heating heat-sealing layers 121 constituting the inner surfaces of pair of protection films 120 to bond them together, and a heating member (not shown) having a certain width may be used.

[0031] The third step is to cut off the unnecessary edge portion of graphite heat dissipation member 160 using cutting means 190 to complete graphite heat dissipation sheet 100. Cutting means 190 may be configured in a manner commonly used in the industry, and may be configured to cut off and remove the unnecessary edge portion of graphite heat dissipation member 160. At this time, it is preferable to cut so that the edge portion of final graphite heat dissipation sheet 100 has a minimum bezel.

[0032] 3 is a schematic diagram of a method for manufacturing a graphite heat dissipation sheet according to another embodiment of the present invention. As shown in FIG. 3, the method for manufacturing a graphite heat dissipation sheet according to this embodiment includes the following steps: a first step of inserting graphite sheet 310 of a certain width into film pouch (envelope) 320 having a heat-sealable layer on the inner surface and an open side; a second step of applying a vacuum to film pouch 320 with an open side to evacuate the inside of graphite sheet 310, heat-sealing opening 321 of film pouch 320 to completely seal graphite sheet 310, applying heat to the surface of film pouch 320 to heat-seal the surface to graphite sheet 310; and a third step of cutting the edge of graphite sheet 310. Film pouch 320 according to this embodiment is preferably constructed by heat-sealing three sides of the film.

[0033] In this embodiment, the graphite heat dissipation sheet manufacturing method uses a film pouch (envelope) 320 having a heat seal layer on the inner surface and an open side, and the final graphite heat dissipation sheet is completed by performing the same first, second, and third steps as the manufacturing method shown in Figure 1, so a description thereof will be omitted. In Figure 3, reference numeral 360 denotes a graphite heat dissipation member, 370 denotes a vacuum chamber, 380 denotes upper and lower heating members, and 390 denotes cutting means.

[0034] The method for producing a graphite heat dissipation sheet of the present invention involves wrapping a graphite sheet in a protective film or pouch having a heat-sealing layer on its inner surface, evacuating the interior to remove gas and moisture from the graphite sheet, and applying heat to the heat-sealing layer, thereby producing a graphite heat dissipation sheet in which the graphite sheet is more firmly integrated with the protective film or pouch due to the fusion effect between the graphite sheet and the surface of the protective film or pouch in a molten state and the pressure bonding effect caused by the pressure difference due to the vacuum.

[0035] The technical details of the method for manufacturing a graphite heat dissipation sheet of the present invention have been described above with reference to the accompanying drawings, which illustrate the most preferred embodiment of the present invention. Therefore, the present invention is not limited to the above embodiment, and various modifications and variations can be made without departing from the spirit and scope of the present invention, as would be obvious to those skilled in the art. Therefore, such modifications and variations should also be considered to fall within the scope of the present invention. [Industrial Applicability]

[0036] The graphite heat dissipation sheet of the present invention can be configured as a thin film and not only has excellent heat dissipation performance, but can also be conveniently attached to heat-generating parts of electronic devices (such as TVs).

Claims

1. a first step of placing a graphite sheet of a certain width between a pair of films each having a thermoplastic heat-sealing layer that melts at a certain temperature on its inner surface, and heat-sealing both sides of the pair of films to seal both sides of the graphite sheet; a second step of evacuating the inside of the graphite sheet with both sides sealed, heat-sealing the openings of the pair of films to completely seal the graphite sheet, and applying heat to surfaces of the pair of films to melt the heat-sealing layers, thereby heat-sealing the graphite sheet to surfaces of the pair of protective films; and a third step of cutting edge portions of the graphite sheet.

2. 2. The method for manufacturing a graphite heat dissipation sheet according to claim 1, wherein the first step includes the steps of: continuously supplying the pair of films by a film supply means; inserting the graphite sheet between the pair of films; and heat-sealing both sides of the pair of films to seal both sides of the graphite sheet; and cutting the pair of films to a length sufficient to cover the graphite sheet.

3. 3. The method for manufacturing a graphite heat dissipation sheet according to claim 1, wherein the second step comprises placing the graphite sheet with both sides sealed into a vacuum chamber, evacuating the graphite sheet for a certain period of time, and then pressing the sheet with upper and lower heating members to perform the evacuation, heat sealing of the openings, and surface heat sealing all at once in the vacuum chamber.

4. 3. The method for manufacturing a graphite heat dissipation sheet according to claim 1, wherein the second step includes the steps of: placing the graphite sheet with both sides sealed into a vacuum chamber, evacuating the graphite sheet for a certain period of time, and then heating and pressing the sheet to perform the evacuation and thermal fusion of the openings; and placing the sheet into a high-temperature chamber and heating the sheet to thermally fusion-bond the surfaces of the pair of films and the graphite sheet.

5. A first step is to insert and place a graphite sheet of a certain width into a film-like pouch having a thermoplastic heat-sealing layer on the inner surface thereof that melts at a certain temperature and one side of which is open; a second step of applying a vacuum to the film pouch having an opening at one side to evacuate the inside of the graphite sheet, heat-sealing the opening of the film pouch to completely seal the graphite sheet, and applying heat to the surface of the film pouch to melt a heat-sealing layer, thereby heat-sealing the graphite sheet to the surface of the film pouch; and a third step of cutting edge portions of the graphite sheet.

6. 6. The method of claim 5, wherein the second step comprises placing the film pouch with the graphite sheet disposed therein into a vacuum chamber, evacuating the film pouch for a predetermined period of time, and then pressing the film pouch with upper and lower heating members to simultaneously perform the evacuation, heat sealing of the opening, and surface heat sealing within the vacuum chamber.

7. 6. The method for manufacturing a graphite heat dissipation sheet according to claim 5, wherein the second step includes the steps of: placing the film pouch with the graphite sheet disposed therein into a vacuum chamber, evacuating the film pouch for a certain period of time, and then heating and pressing the film pouch to perform the evacuation and heat sealing of the opening; and placing the film pouch into a high-temperature chamber and heating the film pouch to perform surface heat sealing of the film pouch and the graphite sheet.

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