KR101603582B1 - Thermal diffusion sheet having a flexible layer of ceramic-carbon composite - Google Patents

Abstract

The present invention relates to a pressure-sensitive adhesive sheet, A low rigidity composite resin layer adhered on the adhesive layer and containing 5 to 40% by weight of a ceramic-carbon composite material and 60 to 95% by weight of a resin; A composite resin adhesive layer adhered on the low rigidity composite resin layer; And a heat dissipation sheet using a low-stiffness layer containing a ceramic-carbon composite material attached to an upper portion of the composite resin adhesive layer and including a metal heat dissipation layer made of a thermally conductive metal.
Therefore, it is possible to provide a composite resin layer containing a metal heat dissipation layer and a ceramic-carbon composite material, thereby realizing heat spreading function, electrical insulation, electromagnetic wave shielding, and external shape maintenance function of a thermal diffusion sheet. Can be reduced to two layers of the composite resin layer and the metal heat dissipation layer, so that the thickness of the thermal diffusion sheet is drastically reduced, and the composite resin layer can serve as the elastic cushion.

Description

TECHNICAL FIELD [0001] The present invention relates to a thermal diffusion sheet using a low-stiffness layer containing a ceramic-carbon composite,

The present invention relates to a ceramic-carbon composite-containing multifunctional thermal diffusion sheet, and more particularly to a multifunctional thermal diffusion sheet containing a ceramic-carbon composite-containing composite resin layer, such as a conventional heat dissipation layer, a heat conduction layer or a thermal diffusion layer, And a heat dissipation layer to protect the circuit from electromagnetic wave shielding and static electricity against high frequency radiation noise and to dissipate heat generated from a semiconductor element, a display light emitting element, or various electronic parts, which are heat emitting bodies, To a thermal diffusion sheet containing a ceramic-carbon composite material capable of rapidly diffusing heat in a sheet as well as in a vertical direction.

BACKGROUND ART Market demands for high performance and miniaturization in the field of electronic devices such as smart phones, displays and portable computers in recent years include the development of technologies for electronic components such as CPUs (central processing units), ICs (integrated circuits, integrated circuits) Thereby increasing the power consumption density and the heat generation amount. Current technology development is in a situation where low power consumption can not catch up with high performance. High heat dissipation materials, low-power devices, and thermo-fluid analysis software for electronic devices are becoming a hot issue.

When heat is accumulated in the electronic component, the processing performance in the electronic component decreases, and the electronic component becomes liable to be damaged. Causing a problem such as electric short-circuiting in the high-pressure generating part, shortening the service life of the product, causing the product to malfunction and causing the reliability of the product to deteriorate. In extreme cases, it may cause explosion and fire. In addition, an increase in the temperature of the surface of the product gives an uncomfortable feeling to the user of the electronic device.

In addition, as the use of electronic communication equipment has been rapidly increasing recently, concerns and concern about harmful effects of electromagnetic waves have increased, and research results that have a negative effect on electromagnetic waves have been announced successively. It is spurting.

Generally, a heat sink is applied to a heat generating element such as a CPU or a semiconductor as a thermal conduction and a heat radiation method of a high-tech digital product as described above. A heat sink of a display backlight unit, a battery, A sheet, a thermal diffusion sheet, or the like is applied to realize the function of conducting and radiating heat generated in the electric parts.

Conventionally, metals such as copper (thermal conductivity of 350 to 400 W / mK) and aluminum (thermal conductivity of 220 to 250 / mK) having excellent thermal conductivity have been used as methods for efficiently removing heat. However, a sheet made of a metal such as copper or aluminum has excellent heat conduction in the vertical plane (through plane) due to the isotropy in heat conduction, but has a problem in that heat conduction can not be realized in a horizontal plane (in plane).

In recent years, a thermal diffusion sheet having a high horizontal thermal conductivity has been required in order to make the thermal conductivity of the electronic products thinner. Accordingly, sheets using graphite (thermal conductivity of 400 to 1500 W / mK) having excellent thermal conductivity in the horizontal direction are used. However, since the conventional heat diffusion sheet using graphite has both excellent thermal conductivity and electrical conductivity, when the sheet is used, it is possible to reduce malfunction and loss of equipment due to heat generation. However, if a withstand voltage of a certain voltage or more is applied, There is a problem. In addition, when it is desired not to exhibit conductivity, it is necessary to take measures against insulation.

In order to solve the above-mentioned problems of the heat-diffusing sheet, as a conventional sheet-like technique, a heat-conducting layer formed by a composition including a polymer and a thermally conductive filler is disclosed in Japanese Patent Laid-Open Publication No. 2008-0076761. A thermal diffusion layer provided on a surface of the thermally conductive layer and formed by a metal material; And a heat insulating layer provided on the surface of the thermal diffusion layer and formed of an electrically insulating material.

In addition, Japanese Patent No. 10-1235541 proposes a multifunctional thin film sheet including a heat radiation and thermal diffusion layer made of an inorganic material having thermal conductivity, an electromagnetic wave shielding function layer made of a metal foil, and a polymer elastic cushion layer.

In addition, in Patent Document 10-2007-0003629, a heat dissipation layer using graphite; A barrier layer for realizing electrical insulation; A thermal diffusion sheet having an elastic layer absorbing impact is proposed.

In order to realize the thermal diffusion function, the electric insulation function, and the electromagnetic wave shielding function, the above three technologies constitute the thermal diffusion sheet by stacking the layers having the respective functions, and the structure and the manufacturing procedure are complicated And the thickness of the thermal diffusion sheet product is thicker than necessary.

From the viewpoint of reducing the thickness and weight of the thermal diffusion sheet and simplifying the manufacturing procedure, it is required to provide an electric insulating function, an electromagnetic shielding function and an outer sheet holding function in a smaller number of layers. However, .

The present invention uses a low-rigidity cushioning functional layer made of a composite resin containing a ceramic-carbon composite material on a conventional metal-based thermal diffusion sheet to maximize the connection with the substrate and to improve the thermal diffusion function, the electric insulation property, the electromagnetic shielding function, And to provide a thermal diffusion sheet that implements the maintenance function.

The present invention relates to a pressure-sensitive adhesive sheet, A low rigidity composite resin layer adhered on the adhesive layer and containing 5 to 40% by weight of a ceramic-carbon composite material and 60 to 95% by weight of a resin; A composite resin adhesive layer adhered on the low rigidity composite resin layer; And a heat dissipation sheet using a low-stiffness layer containing a ceramic-carbon composite material attached to an upper portion of the composite resin adhesive layer and including a metal heat dissipation layer made of a thermally conductive metal.

Further, the release layer may further include a paper or polymer film under the adhesive layer.

(A) having an average diameter of from 0.01 nm to 500 탆, and the following functional group or coupling agent (B) chemically bonded or physically adsorbed on the surface of the carbon material (A) And a ceramic (C) containing the following ceramic (B) bonded to the carbon body (A) via the above-mentioned functional group or coupling agent (B).

A: Graphite, Expandable Graphite, Expanded Graphite, Graphene, Carbon fiber, Carbon Nano Fiber and Carbon Nanotubes (CNTs) At least one carbon material selected from the group consisting of carbon,

B: at least one functional group or coupling agent selected from the group consisting of a hydroxyl group, a carboxyl group, a silane coupling agent, a zirconia coupling agent, a titanate coupling agent and a polymer having N-alkyl or N, N-

C: At least one ceramic selected from the group consisting of magnesium oxide (MgO), aluminum oxide (Al ₂ O ₃ ), zinc oxide (ZnO), zirconium oxide (ZrO ₂ ) and silica (SiO ₂ ).

The metal heat dissipation layer may be at least one selected from the group consisting of copper, aluminum, silver and iron.

Here, the metal heat dissipation layer may be coated with silica or an insulating polymer in a thickness of 400 to 500 탆.

Also, the low-stiffness functional layer has a thermal conductivity of 2.0 to 300 W / mK and an electrical resistance of 10 ⁸ to 10 ¹⁸ ohm / sq and may have an electromagnetic wave shielding function.

The composite resin adhesive layer is composed of at least one selected from the group consisting of a polyvinyl resin, an epoxy resin, an acrylic resin, a silicone resin, a urethane resin, a thermoplastic urethane resin, and a thermoplastic resin ester resin. By weight of the ceramic-carbon composite.

The resin of the low-rigidity composite resin layer may be selected from the group consisting of polyethylene, polypropylene, polyvinyl fluoride, polyvinyl alcohol, polyvinylamide, epoxy, acrylic, silicone, urethane, thermoplastic urethane and thermoplastic ether ester It can be more than one.

The adhesive layer may be at least one selected from the group consisting of epoxy, urethane, acrylic and silicone.

The release layer may include a polyethylene resin layer coated on one side with a paper or polymer film, and a silicone resin layer or fluorine resin layer coated on the polyethylene resin layer.

The ceramic-carbon composite material may have a length of 0.01 to 500 탆 in average diameter and may be formed into a spherical shape, a rod shape, a needle shape, a planar shape, a laminated planar shape, a spindle shape or a fibrous shape.

The thermal diffusion sheet using the ceramic-carbon composite material-containing low-stiffness layer according to the present invention comprises a metal heat dissipation layer and a composite resin layer containing a ceramic-carbon composite material and has a heat diffusion function, electrical insulation, electromagnetic shielding, And the number of the functional layers of the multilayer that constitutes the existing sheet can be reduced to two layers of the composite resin layer and the metal heat dissipation layer so that the thickness of the thermal diffusion sheet is drastically reduced, Can play a role.

1 is a structural view of a thermal diffusion sheet using a low-rigidity composite resin layer containing a ceramic-carbon composite according to an embodiment of the present invention.
2 is a configuration diagram of a thermal diffusion sheet using a low-rigidity composite resin layer containing a ceramic-carbon composite according to another embodiment of the present invention.

As a result of efforts to produce a thermal diffusion sheet having a thermal diffusion function and an electromagnetic shielding function, the present inventors have found that a ceramic-carbon composite material having both thermal conductivity and electrical insulation properties is coated by coating ceramic on graphite having excellent thermal conductivity, Were mixed to prepare a low-rigidity composite resin layer. And the low-rigidity composite resin layer functions as an elastic cushion layer capable of shock absorption, thereby completing the present invention.

The present invention relates to a pressure-sensitive adhesive sheet, A low rigidity composite resin layer adhered on the adhesive layer and containing 5 to 40% by weight of a ceramic-carbon composite material and 60 to 95% by weight of a resin; A composite resin adhesive layer adhered on the low rigidity composite resin layer; And a heat dissipation sheet using a low-stiffness layer containing a ceramic-carbon composite material attached to an upper portion of the composite resin adhesive layer and including a metal heat dissipation layer made of a thermally conductive metal.

The adhesive layer may include at least one selected from the group consisting of epoxy, acrylic, and silicone.

The adhesive layer allows the thermal diffusion sheet using the ceramic / carbon composite-containing low-stiffness layer to be easily attached to a surface such as a printed circuit board (PCB) that is not uniform in surface.

The low-stiffness composite resin layer contains 5.0 to 40.0% by weight of the ceramic-carbon composite and 60.0 to 95.0% by weight of the resin. Under these conditions, the low-stiffness composite resin layer exhibits excellent contact ability even on the surface, Respectively.

The metal heat dissipation layer may be any one selected from copper having a thermal conductivity of 350 to 400 W / mK and aluminum, silver and iron having a thermal conductivity of 220 to 250 W / mK.

Under the above conditions, the metal heat dissipation layer combined with the low rigidity composite resin layer increased thermal conductivity and electrical resistance.

It is also possible that the copper, aluminum, silver and iron are manufactured in a mixed alloy of a certain weight.

More particularly, the present invention relates to an alloy containing 85.0 to 98.0% by weight of copper and 2.0 to 15.0% by weight of aluminum, an alloy containing 85.0 to 99.5% by weight of copper and 0.5 to 15.0% by weight of iron, 85.0 to 99.2% 15.0% by weight is preferably used.

It is possible to increase the thermal conductivity in the thickness direction and the horizontal direction of the thermal diffusion sheet using the ceramic-carbon composite low-stiffness layer in the case of adhering the metal heat dissipation layer having excellent thermal conductivity to copper and aluminum to the low stiffness composite resin layer .

A pressure-sensitive adhesive layer was formed on the low-rigidity composite resin layer using a roll pressing method, and a releasing layer, which is easy to peel off, was adhered to the lower portion of the low-rigidity composite resin layer using the compression bonding method, Containing ceramic-carbon composite containing a low-stiffness layer.

The ceramic-carbon composite is prepared by introducing a functional group or coupling agent capable of chemically bonding or physically adsorbing to a carbon body and a surface of a carbon body several hundreds of micro-nanometers to react with the ceramic precursor via the functional group or the coupling agent The composite resin layer was prepared by coating the surface of the carbon body with a sol-gel process. The resin layer was mixed with the resin layer to produce a low-rigidity composite resin layer that acts as a shock-absorbing elastic cushion.

On the other hand, it has been confirmed that the low-rigidity composite resin layer containing the ceramic-carbon composite material has an electric resistance of 10 ⁸ to 10 ¹⁸ ohm / sq and has an electromagnetic wave shielding function.

The release layer may comprise a polyethylene resin layer coated on one side with a paper or polymer film, and a silicone resin layer or fluorine resin layer coated on the polyethylene resin layer, in which case the adhesion ability can be greatly increased.

Hereinafter, the present invention will be described in detail with reference to specific examples and comparative examples. However, the present invention is not limited to these examples.

< Example  1>

1 g of poly (N-vinylpyrrolidone; PVP) was dissolved in 100 g of ethanol at room temperature, and 1 g of graphite was added thereto. After stirring for 1 hour, the surface of the graphite was subjected to a filter process and a drying process. 0.8 g of graphite surface-treated with PVP was added to 90 g of ethanol and an aqueous ammonia solution was added so that the pH became 11.1. After that, 0.8 g of TEOS (Tetraethy Orthosilicate) was added at room temperature and under nitrogen atmosphere, and the mixture was stirred for 12 hours, followed by filtering and drying to prepare a ceramic-carbon composite (silica-graphite composite).

The ceramic-carbon composite prepared through the above method was blended with a polyvinyl resin to prepare a low-rigidity composite resin layer.

The low-rigidity composite resin layer was adjusted to 25.0% by weight based on the total weight of the low-rigidity composite resin layer by adding 10.13 g of the ceramic-carbon composite prepared for 30.21 g of the thermoplastic polyvinyl resin. In addition, 0.2 g of crosslinking agent hexamethylene diisocyanate was added and crosslinked.

A copper plate with a thermal conductivity of 400 W / mK was prepared, and a polyethylene resin and a polyether ester resin were mixed in a weight ratio of 50:50 at the lower part thereof to prepare a composite resin adhesive layer. A low-rigidity composite resin layer, a composite resin adhesive layer, and a metal heat dissipating plate were sequentially laminated on the adhesive layer and adhered thereto by thermocompression bonding.

A thermal diffusion sheet having a structure as shown in FIG. 1 was prepared by attaching an acrylic adhesive layer and a polyethylene separator layer to the lower part of the sheet to which the metal heat dissipation layer, the composite resin adhesive layer, and the low stiffness functional layer were bonded using a roll pressing method.

< Comparative Example   1>

A thermal diffusion sheet was prepared by adding 12 g of a mixture of glass fiber and polyester woven fabric commonly used in a composite resin obtained by blending 24 g of pure graphite and 12 g of a polyvinyl resin as a reinforcing material and adding 0.2 g of a crosslinking agent hexamethylene diisocyanate.

< Comparative Example  2>

A thermal diffusion sheet product of Graftech Co., Ltd. having a resin layer and an adhesive layer containing pure graphite and resin was prepared.

< Comparative Example  3>

A thermal diffusion sheet product of Panassonic Co. was prepared using a pyrolytic graphite sheet (PGS) layer, a rubber layer and an adhesive layer.

< Comparative Example  4>

A product of Advanced energy technology was prepared using a resin layer and an adhesive layer in which graphite treated with intercalant of sulfuric acid and nitric acid was mixed with a resin.

< Experimental Example  1>

The thermal diffusion sheet prepared according to Example 1 and the samples of Comparative Examples 2 to 4 were measured according to the American Society for Testing and Materials (ASTM E 1461) and measured according to the American Society for Testing and Materials (ASTM D 257) The resistance was measured and the electromagnetic shielding performance was measured according to the American Society for Testing and Materials (ASTM D 4935).

The measured results are shown in Table 1.

Functional layer filler Thermal conductivity
In-Plane (W / mK) Thermal conductivity
Through-Plane (W / mK) Electrical sheet resistance (ohm / sq) The degree of electromagnetic shielding (A / B / C) Example 1 Metal-ceramic-carbon composite 300 80 10 ¹⁴ A Comparative Example 1 Graphite-glass fiber composite 12 4.0 10 ⁷ C Comparative Example 2 black smoke 400 4.5 10 ³ B Comparative Example 3 Pyrrolitic graphite 500 4.7 10 ² B Comparative Example 4 Acid treated graphite 280 7 10 ⁴ B

The thermal diffusion sheet using the ceramic-carbon composite-containing low-stiffness layer prepared in Example 1 was compared with Comparative Examples 2 to 4 with reference to Table 1, and the thermal conductivity values of the ceramic-carbon composite material according to the embodiment of the present invention The thermal diffusion sheet using the low-stiffness-containing layer has a slightly lower thermal conductivity (about 60 to 93%) in the horizontal direction (In-Plane) compared with the comparative example 2 and the comparative example 3, Which is very good.

In addition, it was confirmed that the horizontal direction was slightly increased to 120% and the vertical direction was greatly increased as compared with Comparative Example 4, and the thermal conductivity of the through-plane in the case of including the metal heat sink layer was greatly increased.

In addition, when the sheet resistance values of Example 1 were compared with those of Comparative Examples 2 to 4, it was confirmed that the ceramic-carbon composite containing thermal diffusion sheet of the present invention had higher electric insulation than Comparative Examples 2 to 4. And Comparative Examples 2 to 4 were found to be electrical sheet resistance levels of a composite composed of graphite and resin at 10 ² to 10 ⁴ ohm / sq. Compared with the comparative examples 2 to 4, the ceramic-carbon composite thermal diffusion sheet according to the embodiment of the present invention achieved a complete electrical insulation at a level of 10 ¹³ ohm / sq.

In comparison of Example 1 with Comparative Examples 2 to 4, when the electromagnetic wave shielding levels were compared, the thermal volcanic sheet using the ceramic-carbon composite low-stiffness layer according to the embodiment of the present invention was comparable to the graphite- 3 electromagnetic wave shielding level B.

The tensile behavior of low - stiff composite resin layer was examined to confirm the role of elastic cushion of low - stiffness composite resin layer. A dumbbell specimen was prepared based on ASTM D638-10, and a specimen was prepared with a center measurement area width of 5 mm, a center measurement area length of 2.0 mm, and a total length of 130 mm.

 The tensile strain of the low-stiffness composite resin layer was examined using a tensile testing machine, and a hardness test was carried out using a Shore A test piece with two 50 mm width and 100 mm length 2 mm specimens.

Item Tensile Strength (MPa) Stiffness (ShA) Low rigidity composite resin layer 30 50A Comparative Example 1 40 80A Remarks The low-rigidity composite resin layer had a 75% The low-rigidity composite resin layer contained 62.5% of Comparative Example 1,

Table 2 shows a comparison between the tensile strength and the hardness of Comparative Example 1 prepared according to the conventional graphite composite manufacturing method and the low-rigidity composite resin layer containing the ceramic-carbon composite according to the embodiment of the present invention.

In the case of the low-stiffness composite resin layer, the tensile strength at the level of 75% and the hardness at the level of 63% in Comparative Example 1 were shown, which has a better cushioning feel than Comparative Example 1, Respectively.

And the heat radiation performance of the metal heat dissipation layer was evaluated. The thermal diffusion sheet using the ceramic-carbon composite low-stiffness layer prepared in Example 1 and the Comparative Example 1 were placed in front of a heat source of 80 ° C. After one hour, the temperature at a position 2.5 cm away from the heat source was measured and compared.

The surface of the thermal diffusion sheet using the ceramic-carbon composite-containing low-stiffness layer prepared in Example 1 was found to be about 42 ° C, whereas in Comparative Example 1, the heat radiation performance of the metal heat dissipation layer was significantly increased .

While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, And various modifications and variations are possible within the scope of the appended claims.

100: Thermal diffusion sheet containing ceramic-carbon composite
200: Thermal diffusion sheet containing a ceramic-carbon composite with a release layer removed
10: metal heat dissipating layer
20: Composite resin adhesive layer
30: Low rigidity composite resin layer
40: Adhesive layer
50:

Claims (11)

An adhesive layer;
A low-rigidity composite resin layer adhered on the adhesive layer and containing 5 to 40% by weight of a ceramic-graphite composite and 60 to 95% by weight of a resin;
A composite resin adhesive layer adhered on the low rigidity composite resin layer; And
And a metal heat dissipation layer attached to the upper portion of the composite resin adhesive layer and made of a thermally conductive metal,
The low-stiffness composite resin layer has a thermal conductivity of 2.0 to 300 W / mK, an electrical resistivity of 10 ⁸ to 10 ¹⁸ ohm / sq, and a hardness of 50 A. Thermal diffusion sheet using. The thermal diffusion sheet according to claim 1, further comprising a release layer comprising a paper or polymer film under the adhesive layer, the low-rigidity layer containing a ceramic-graphite composite. The ceramic-graphite composite according to claim 1 or 2, wherein the ceramic-graphite composite comprises graphite having an average diameter of 0.01 nm to 500 탆, the following functional group or coupling agent (B) chemically bonded or physically adsorbed on the graphite surface, Graphite composite-containing low-stiffness layer, characterized in that the graphite-graphite composite-containing low-stiffness layer includes the following ceramic (C) bonded to and coated with graphite via the functional group and the coupling agent (B)
B: at least one functional group or coupling agent selected from the group consisting of a hydroxyl group, a carboxyl group, a silane coupling agent, a zirconia coupling agent, a titanate coupling agent and a polymer having N-alkyl or N, N-
C: At least one ceramic selected from the group consisting of magnesium oxide (MgO), aluminum oxide (Al ₂ O ₃ ), zinc oxide (ZnO), zirconium oxide (ZrO ₂ ) and silica (SiO ₂ ). The thermal diffusion sheet according to claim 1, wherein the metal heat dissipation layer is at least one selected from the group consisting of copper, aluminum, silver and iron. The thermal diffusion sheet using the ceramic / graphite composite-containing low-stiffness layer according to claim 1, wherein the metal heat-dissipating layer is formed by coating silica or an insulating polymer with a thickness of 400 to 500 탆. delete The composite resin adhesive layer according to claim 1, wherein the composite resin adhesive layer is composed of at least one selected from the group consisting of polyvinyl, epoxy, acrylic, silicone, urethane, thermoplastic urethane, Wherein the ceramic-graphite composite contains 1 to 40 parts by weight of the ceramic-graphite composite. The resin composition according to claim 1, wherein the resin of the low-rigidity composite resin layer is at least one selected from the group consisting of polyethylene, polypropylene, polyvinyl fluoride, polyvinyl alcohol, polyvinylamide, epoxy, acrylic, silicone, urethane, thermoplastic urethane and thermoplastic ether ester Wherein the low-rigidity layer contains at least one selected from the group consisting of ceramic, graphite, and graphite. The thermal diffusion sheet of claim 1, wherein the adhesive layer is at least one selected from the group consisting of epoxy, urethane, acrylic, and silicone. The ceramic-graphite composite according to claim 2, wherein the release layer comprises a polyethylene resin layer coated on one side with a paper or polymer film, and a silicone resin layer or fluorine resin layer coated on the polyethylene resin layer. Thermal diffusion sheet using low stiffness layer. The ceramic-graphite composite according to claim 3, wherein the ceramic-graphite composite has an average major axis diameter of 0.01 to 500 탆 and is formed into a spherical shape, a rod shape, a needle shape, a planar shape, a laminated planar shape, Containing low stiffness layer.

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