WO2014025154A1 - Heat radiation sheet and method for manufacturing same - Google Patents

Abstract

A heat radiation sheet according to the present invention comprises: a heat radiation layer formed as a web form having a plurality of pores by electrospinning polymeric material and a solvent, or a spinning solution which is a mixture of polymeric material, heat-conducting material and a solvent; and an adhesion layer laminated on one or both sides of the heat radiation layer, and formed as a web by electrospinning adhesive material which is a mixture of an adhesive, heat-conductive material and a solvent.

Description

Heat dissipation sheet and its manufacturing method

The present invention relates to a heat dissipation sheet installed in an electronic device to discharge heat generated inside the device to the outside, and more particularly, to a heat dissipation sheet manufactured in the form of a nano-web by an electrospinning method and a method of manufacturing the same.

In general, electronic devices such as computers, portable personal terminals, and communication devices do not diffuse excessive thermal energy generated inside the device to the outside, which causes serious afterimage problems and system stability. This thermal energy shortens the life of the product, causes failures and malfunctions, and in severe cases can also cause explosions and fires.

In particular, the current electronic devices are thinner and thinner and their performance is higher. Therefore, the electronic devices must be quickly discharged to the outside to prevent the electronic devices from being damaged by heat. Therefore, the heat radiation sheet is used to release the heat energy generated inside the system to the outside.

The conventional heat dissipation sheet is a heat conductive metal plate, as disclosed in Korean Patent Publication No. 10-0721462 (May 17, 2007), and a tacky adhesive formed on at least one side of the metal plate and having a cell as a foam structure therein. It includes a foam sheet, wherein the adhesive foam sheet is formed of an adhesive mixture containing a pressure-sensitive adhesive and a cell-forming agent, the pressure-sensitive adhesive is an acrylic resin, a silicone resin or a polyurethane resin, the cell forming agent is composed of a micro hollow tool do.

However, the conventional heat dissipation sheet has a problem that it is difficult to use a thin thickness electronic devices such as portable electronic devices because the thickness is thick because the adhesive foam sheet is attached to the surface of the metal plate.

In addition, the heat dissipation sheet is used to punch out according to the size of the heat generating part to attach to the heat generating parts of the electronic device, in the case of the conventional heat dissipation sheet, there is a problem that precise punching is difficult because the foam sheet has adhesiveness when punching.

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat dissipation sheet and a method of manufacturing the same, which are manufactured in the form of a nanoweb by an electrospinning method to improve the thermal conductivity while making the thickness thin.

Another object of the present invention is to produce a pressure-sensitive adhesive layer for attaching to the heating element by the electrospinning method, it is possible to improve the punchability and the heat-conductive material is included, the adhesive layer can also have a heat dissipation performance can improve heat dissipation performance It is to provide a heat dissipation sheet and a method of manufacturing the same.

The problem to be solved by the present invention is not limited to the technical problem mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description. .

In order to achieve the above object, the heat dissipation sheet of the present invention comprises a heat dissipation layer formed in the form of a web having a plurality of pores by electrospinning a spinning solution mixed with a polymer material and a solvent, or a polymer material, a heat conductive material and a solvent; And an adhesive layer formed on one side or both sides of the heat dissipating layer and electrospinning an adhesive material mixed with an adhesive, a heat conductive material, and a solvent to form a web.

The heat dissipation sheet of the present invention is a substrate in the form of a web formed by the electrospinning method; An adhesive layer laminated on one surface of the substrate; And a metal layer coated on the other side of the substrate and having a thermal conductivity.

Method for producing a heat dissipation sheet of the present invention comprises the steps of electrospinning the pressure-sensitive adhesive material, the heat conductive material and the solvent mixed adhesive material to form a pressure-sensitive adhesive layer of the nano-web form; And forming a heat dissipating layer in the form of a web by electrospinning a spinning solution in which a polymer material and a solvent, or a polymer material, a heat conductive material and a solvent are mixed on one surface of the adhesive layer.

As described above, the heat dissipation sheet of the present invention is manufactured in the form of a web by the electrospinning method, thereby making the thickness thin, and there is an advantage that it can be applied to a thin electronic device.

In addition, the heat dissipation sheet of the present invention may be produced in the form of a web by electrospinning the pressure-sensitive adhesive layer to improve the punchability, and includes a heat conductive material in the pressure-sensitive adhesive layer has the advantage of improving the heat dissipation performance.

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

2 is an enlarged view of a heat radiation layer according to a first embodiment of the present invention.

3 is a cross-sectional view of a heat radiation sheet according to a second embodiment of the present invention.

Figure 4 is a block diagram of an electrospinning apparatus for producing a heat radiation sheet of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this process, the size or shape of the components shown in the drawings may be exaggerated for clarity and convenience of description. In addition, terms that are specifically defined in consideration of the configuration and operation of the present invention may vary depending on the intention or custom of the user or operator. Definitions of these terms should be made based on the contents throughout the specification.

1 is a cross-sectional view of a heat radiation sheet according to a first embodiment of the present invention, Figure 2 is an enlarged view of a heat radiation sheet according to a first embodiment of the present invention.

The heat dissipation sheet according to the first embodiment is formed by the electrospinning method and includes a heat conductive material, the heat dissipation layer 10 in the form of a nano-web having thermal conductivity, and adhesively laminated on one or both surfaces of the heat dissipation layer 10. Layer 20.

The heat dissipating layer 10 forms a spinning solution by mixing a polymer material and a solvent capable of electrospinning, or a polymer material, a heat conducting material and a solvent in a predetermined ratio, and electrospinning the spinning solution to form the nanofibers 14, The nanofibers 14 are accumulated to form a nano web having a plurality of pores 12. Here, the nano web may be referred to as a web.

Here, the radiation method applied to the present invention is a general electrospinning, air electrospinning (AES: Air-Electrospinning), electrospray (electrospray), electrobrown spinning, centrifugal electrospinning Flash-electrospinning can be used.

That is, the radiation layer 10 and the adhesive layer 20 of the present invention can be applied to any spinning method of the spinning method that can be made in the form of the nanofibers accumulated.

The polymeric material used to make the heat dissipating layer 10 may be, for example, polyvinylidene fluoride (PVDF), poly (vinylidene fluoride-co-hexafluoropropylene), perfuluropolymer, polyvinyl chloride or poly Polyethylene including vinylidene chloride and copolymers thereof and polyethylene glycol derivatives including polyethylene glycol dialkyl ether and polyethylene glycol dialkyl ester, poly (oxymethylene-oligo-oxyethylene), polyethylene oxide and polypropylene oxide , Polyvinyl acetate, poly (vinylpyrrolidone-vinylacetate), polystyrene and polystyrene acrylonitrile copolymer, polyacrylonitrile copolymer including polyacrylonitrile methyl methacrylate copolymer, polymethyl methacrylate , Polymethyl methacrylate copolymers and mixtures thereof This may be used.

The thermally conductive material may be any one of thermally conductive metals such as Ni, Cu, and Ag, and conductive carbon, carbon black, carbon nanotubes, and conductive polymers (PDOT). In addition, any material may be used as long as the material has thermal conductivity.

Here, when the spinning solution is prepared by mixing the thermally conductive particles, the polymer material, and the solvent applied as the thermally conductive material, the thermally conductive particles are dispersed in the nanofibers 14 of the heat dissipating layer 10 in the form of a nanoweb. . That is, part of the thermally conductive particles are exposed to the surface of the nanofibers 14 of the heat dissipation layer 10 to participate in thermal conduction.

Since the heat radiation layer 10 is manufactured by the electrospinning method, the thickness is determined according to the radiation amount of the spinning solution. Therefore, there is an advantage that it is easy to make the thickness of the heat radiation layer 10 to a desired thickness.

As such, since the heat dissipation layer 10 is formed in the form of a nano web in which the nanofibers are accumulated by the spinning method, the heat dissipation layer 10 may be formed in a form having a plurality of pores without a separate process, and the size of the pores is adjusted according to the amount of spinning solution. It is also possible.

The adhesive layer 20 is manufactured by the same electrospinning method as the method of making the heat dissipation layer 10. That is, a pressure-sensitive adhesive, a thermally conductive material and a solvent are mixed to form a thermally conductive adhesive material having a viscosity suitable for electrospinning, and the thermally conductive adhesive material has a predetermined thickness on one or both sides of the heat dissipating layer 10 by an electrospinning method. Laminate.

The adhesive layer 20 is radiated in the form of ultrafine fiber strands and adheres to the surface of the heat dissipating layer 10. At this time, the adhesive material is introduced into the pores 12 of the heat insulating layer 10 to increase the adhesive strength between the heat radiation layer 10 and the adhesive layer 20. Therefore, the phenomenon that the heat dissipation layer 10 peels off from the adhesive layer 20 is reduced, and the reliability of the heat dissipation sheet is improved. In addition, the thickness of the adhesive layer 20 is reduced by the adhesive material introduced into the pores 12 to implement an ultra-thin heat dissipation sheet.

As the heat conductive material forming the adhesive layer 20, the same material as the heat conductive material forming the heat dissipating layer 10 may be used.

Here, the adhesive layer 20 is manufactured by separately manufacturing the heat-dissipating layer 10 and the adhesive layer 20 by an electrospinning method, in addition to the method of directly electrospinning a thermally conductive adhesive material to the heat-dissipating layer 10, and then laminating them. In the process, a method of laminating the thermally conductive adhesive layer 20 on one or both surfaces of the heat dissipation layer 10 may also be applied.

Similarly, the thickness of the adhesive layer 20 is determined according to the radiation amount of the thermally conductive adhesive material. Therefore, the thickness of the adhesion layer 20 can be made free.

As described above, since the adhesive layer 20 includes a heat conductive material, since the adhesive layer 20 has adhesiveness and thermal conductivity to attach the heat dissipation layer to the heat generating parts, the heat dissipation performance may be improved.

In the present invention, thermally conductive particles may be dispersed and disposed between the heat dissipation layer 10 and the adhesive layer 20. Thermally conductive particles are disposed outside the nanofibers of the heat dissipation layer 10 and the nanofibers of the pressure-sensitive adhesive layer 20 positioned on the interface between the heat dissipation layer 10 and the adhesive layer 20. By transferring the generated heat to the heat dissipation layer 10, it is possible to increase the heat dissipation efficiency.

Here, when the thermally conductive particles and the solvent are mixed to make a spray solution, and a bead consisting of the thermally conductive particles and the solvent is sprayed onto the nanoweb of the adhesive layer 20 by an electrospraying process, the solvent is volatilized and thermally conductive. Particles are dispersed in the nanoweb of the adhesive layer 20. Thereafter, when the nanoweb of the heat dissipation layer 10 is formed on the nanoweb of the adhesive layer 20 to which the thermally conductive particles are injected, the thermally conductive particles are formed between the heat dissipation layer 10 and the adhesive layer 20 described above. The heat dissipation sheet arrange | positioned by dispersion | distribution can be manufactured.

In the present invention, the heat dissipation layer 10 quickly diffuses heat generated from a heat generator such as an LED, a CPU, an IC, and the like, thereby preventing a local temperature rise of the heat generator.

3 is a cross-sectional view of a heat radiation sheet according to a second embodiment of the present invention.

The heat dissipation sheet according to the second embodiment is coated on the base 30 of the nano-web form formed by the electrospinning method, the adhesive layer 40 laminated on one side of the base 30, and the other side of the base 30 And includes a metal layer 50 having thermal conductivity.

The substrate 30 mixes a polymer material and a solvent in a predetermined ratio to form a spinning solution having an electrospinable viscosity, and electrospins the spinning solution to form nanofibers, and the nanofibers are accumulated to have a plurality of pores. It is formed in the form of a nano web (nano web).

In addition, the substrate 30 may also have the same structure as the heat dissipation layer 10 in the first embodiment. That is, the substrate 30 may be formed of a polymer material to perform a role of supporting the metal layer, and a structure having a role of supporting a metal layer and a heat conducting role at the same time by including a heat conductive material such as the heat dissipation layer 10. It is also possible to apply.

Here, since the polymer material forming the substrate 30 is the same as the polymer material described in the first embodiment, a detailed description thereof will be omitted.

Since the adhesive layer 40 is the same as the structure of the adhesive layer 20 described in the first embodiment, a detailed description thereof will be omitted.

For example, Ni, Cu, Ag, or the like may be used as the metal having a thermal conductivity, and the metal layer 50 may be applied with a method of attaching a metal foil.

As described above, the heat dissipation sheet according to the second embodiment may be provided with a metal layer 50 having excellent thermal conductivity to further improve heat dissipation performance.

Meanwhile, the metal layer 50 may be implemented as a metal pattern layer coated on the other surface of the substrate 30 in a pattern shape, and the metal pattern layer has a larger contact area than the metal layer 50 having a bulk surface. As a result, the heat dissipation efficiency is increased.

Figure 4 is a block diagram showing an electrospinning apparatus for manufacturing a heat radiation sheet according to the present invention.

The electrospinning apparatus of the present invention comprises a first mixing tank 70 in which a pressure sensitive adhesive, a heat conductive material and a solvent are mixed, and a spinning solution in which an electrospinable polymer material, a heat conductive material, and a solvent are mixed. A first mixing nozzle 72 connected to the high voltage generator and a first radiation nozzle 74 connected to the first mixing tank 70 to form an adhesive layer 20, and The second radiation nozzle 76 connected to the mixing tank 72 to form the heat dissipation layer 10, and disposed below the first radiation nozzle 74 and the second radiation nozzle 76, may be attached to the adhesive layer 20. ) And the heat dissipation layer 10 includes a collector 78 sequentially stacked.

The first mixing tank 70 is provided with a first stirrer 60 to mix the polymer material, the heat conductive material and the solvent evenly, and to maintain a constant viscosity of the spinning solution, and the second mixing tank 72 includes an adhesive, A second stirrer 62 is provided to mix the heat conductive material and the solvent evenly and to maintain the viscosity of the adhesive material.

As the high voltage electrostatic force of 90 to 120 Kv is applied between the collector 78 and the first radiation nozzle 74 and between the collector 78 and the second radiation nozzle 76, the nanofibers 14 are radiated to the collector. 14 is collected to form a nano web.

Here, the first radiation nozzle 74 and the second radiation nozzle 76 may be arranged in plurality, may be arranged sequentially in one chamber, each may be arranged in different chambers.

Each of the first radiation nozzles 74 and the second radiation nozzles 76 is provided with an air injection device 64 so that the nanofibers 14 radiated from the first radiation nozzles 74 and the second radiation nozzles 76 are formed. It is not captured by the collector 78 and prevents it from flying.

Collector 78 is used a conveyor for automatically transferring the release film 82 so that the adhesive layer 20 and the heat dissipation layer 10 are sequentially stacked on the release film 82, or the adhesive layer 20 and the heat dissipation layer The table form can be used when 10 is formed in different chambers.

In front of the collector 78, a release film roll 80 wound around the release film 82 is disposed to supply the release film 82 to the upper surface of the collector 78. In addition, a pressure roller 86 is provided at the rear of the collector 78 to pressurize (calender) the pressure-sensitive adhesive layer 20 and the heat dissipation layer 10 to a predetermined thickness, and is pressed while passing through the pressure roller 86. A sheet roll 88 is provided on which a heat dissipation sheet having a predetermined thickness is wound.

Thus, the process of manufacturing a heat radiation sheet using the electrospinning apparatus comprised is demonstrated below.

First, when the collector 78 is driven, the release film 82 wound around the release film roll 80 is released and supplied to the collector 78.

In addition, by applying a high voltage electrostatic force between the collector 78 and the first radiation nozzle 74, the adhesive material is made into the nanofibers 14 in the first radiation nozzle 74 to radiate onto the surface of the release film 82. . Then, the nanofibers 14 are accumulated on the surface of the release film 82 to form an adhesive layer 20.

Here, since the adhesive layer 20 contains a heat conductive material, the adhesive layer 20 serves to dissipate heat even in the adhesive layer 20 itself.

At this time, when the nano-fiber 14 is radiated by the air injector 64 installed in the first radiation nozzle 74, the air is injected to the nanofibers 14 so that the nanofibers 14 do not fly and the release film 82 does not fly. To be collected and integrated on the surface of the

When the manufacture of the adhesive layer 20 is completed, the adhesive layer 20 is moved to the lower portion of the second radiation nozzle 76 and the high voltage electrostatic force is applied between the collector 78 and the second radiation nozzle 76. As a result, the spinning solution is made into the nanofibers 14 on the adhesive layer 20 in the second spinning nozzle 76 to be spun. Then, the heat radiation layer 10 in the form of a nano web having a plurality of pores 12 on the surface of the adhesive layer 20 is formed.

The heat dissipation sheet completed while going through this process is pressed to a predetermined thickness while passing through the pressure roller (86). Then, it is wound around the sheet roll 88 and stored.

In addition to such a manufacturing method, after separately manufacturing the heat dissipation layer 10 and the adhesive layer 20, the adhesive layer 20 is disposed on one side or both sides of the heat dissipation layer 10, and the heat dissipation layer 10 and adhesive The method of laminating and manufacturing between the layers 30 is also applicable.

Here, each of the heat dissipation layer 10 and the adhesive layer 20 is one of a non-woven fabric, a paper, and a polyolefin-based film such as PE, PP, etc., made of a polymer material that is not dissolved by a solvent used in the spinning solution. After forming on the transfer sheet, the heat-dissipating layer 10 and the adhesive layer 20 is laminated, the process of removing the transfer sheet can be performed.

In addition, when the heat dissipation sheet has a structure in which the metal layer 50 is coated on the surface of the substrate 30 formed by the electrospinning method, the adhesive layer 40 and the substrate 30 are manufactured in the same manner as above, and then the substrate 30 By coating the metal layer 50 on the surface of the) to produce a heat dissipation sheet.

In this case, the substrate 30 may include a heat conducting material in the same manner as the heat dissipation layer 10 described above, and a structure in which only the polymer material is electrospun to perform only a role of the substrate may be applied.

In the above, the present invention has been illustrated and described with reference to specific preferred embodiments, but the present invention is not limited to the above-described embodiments, and the present invention is not limited to the spirit of the present invention. Various changes and modifications will be possible by those who have the same.

The present invention provides a heat dissipation sheet that can be made thin in thickness by manufacturing in the form of a nano-web by the electrospinning method, which can be applied to an electronic device having a thin thickness.

Claims (11)

1. A heat dissipation layer formed into a web having a plurality of pores by electrospinning a spinning solution in which a polymer material and a solvent or a polymer material, a heat conductive material and a solvent are mixed; And

   A heat dissipation sheet including a pressure-sensitive adhesive layer formed on one side or both sides of the heat dissipation layer and electro-spinning the pressure-sensitive adhesive material mixed with a pressure-sensitive adhesive, a heat conductive material and a solvent to form a web.
2. The heat dissipating sheet of claim 1, wherein the thermal conductive material is any one of a thermally conductive metal having excellent thermal conductivity and conductive carbon, conductive carbon black, carbon nanotubes, and conductive polymers (PDOT). .
3. The heat dissipation sheet according to claim 1, wherein the heat conductive material is heat conductive particles, and a part of the heat conductive particles is exposed on the surface of the nanofibers of the web of the heat dissipation layer and the adhesive layer.
4. The heat dissipating sheet according to claim 1, wherein the adhesive layer is in contact with and adhered to a heat generating part of the electronic device.
5. The heat dissipation sheet according to claim 1, wherein thermally conductive particles are dispersed between the heat dissipation layer and the adhesive layer.
6. A substrate in the form of a web formed by an electrospinning method;

   An adhesive layer laminated on one surface of the substrate; And

   A heat radiation sheet comprising a metal layer coated on the other side of the substrate having a thermal conductivity.
7. The method of claim 6, wherein the base material is a web structure having a plurality of pores formed by electrospinning a spinning material containing a polymer material and a solvent, or a polymer material, a heat conductive material and a solvent, the adhesive layer is an adhesive, a heat conductive material And a web structure formed by electrospinning an adhesive material mixed with a solvent.
8. The heat dissipation sheet according to claim 6, wherein the metal layer is a metal pattern layer coated in a pattern shape on the other surface of the substrate.
9. Electrospinning the pressure-sensitive adhesive material mixed with the pressure-sensitive adhesive, the heat conductive material and the solvent to form a pressure-sensitive adhesive layer in the form of a web; And

   On one side of the adhesive layer, a method of manufacturing a heat radiation sheet comprising the step of electrospinning a spinning solution in which a polymer material and a solvent, or a polymer material, a heat conductive material and a solvent are mixed to form a heat radiation layer in the form of a web.
10. 10. The method of claim 9, between the step of forming the adhesive layer in the form of the web and the step of forming the heat dissipation layer in the form of the web,

    A method of manufacturing a heat dissipation sheet further comprising the step of dispersing the thermally conductive particles in a web of the adhesive layer by electrospraying a spray solution mixed with thermally conductive particles and a solvent.
11. The method of claim 9, further comprising pressing the adhesive layer and the heat radiation layer after forming the heat radiation layer in the web form.

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