KR20180129192A - Heat spreader - Google Patents

Abstract

The present invention relates to a heat spreader which is generated by applying a heat dissipation coating composition onto a base of one selected from metal, plastic, film and a printed circuit board, wherein the heat dissipation coating composition is composed of a solvent containing a polyurethane resin, a wetting agent or dispersion stabilizer, a leveling agent, a defoaming agent, and a fluidity-adjusting additive, and a filler dispersed in the solvent and having an average particle diameter of 0.01 to 10 μm. The heat conduction quality of a coating material is improved to enable stable use of electrical and electronic products and the like and miniaturization and ultra-thinness, and to increase the degree of design freedom.

Description

Heat Spreader {HEAT SPREADER}

The present invention relates to a heat spreader, and more particularly, to a heat spreader in which a heat-radiating coating improved in thermal conductivity is applied to a plate-shaped base to enable miniaturization and ultra-thinness by replacing a heat pipe and stable use of an electric / electronic product, The present invention relates to a heat dissipating spreader that ensures autonomy.

Devices used in electrical and electronic devices generate heat when power is supplied, and these heat must be dissipated quickly to the outside through heat pipes, heat sinks, and radiating fins. Recently developed devices have a very high thickness The heat generated by the heat pipe can not be secured enough to install the heat pipe and the heat dissipation pin. Therefore, the generated heat is continuously heated while staying inside the housing of the apparatus, resulting in malfunction, explosion, fire, and the like.

As a prior art for improving heat radiation performance, Korean Patent Laid-Open Publication No. 2012-0046523 discloses a heat dissipation device comprising 130 to 170 parts by weight of inorganic particles, 80 to 120 parts by weight of a binder, 3 to 7 parts by weight of a dispersant, and 40 to 60 parts by weight of a solvent Coating compositions. Examples of the inorganic particles exhibiting a heat dissipating effect include oxides such as oxides, cermets, cordierite, germanium, iron oxide, mica, manganese dioxide, silicon carbide, cryptite, carbon, copper oxide, cobalt oxide, nickel oxide, antimony pentoxide, Chromium, silica, alumina, magnesium oxide, titania, zirconia, zinc oxide, barium titanate, zirconium titanate, and strontium titanate.

However, even with this prior art, there is a problem that the heat dissipation characteristics required for an electronic product that is supersized can not be met.

On the other hand, when graphene or graphene is recently used as the carbon-based material, the coating layer formed by the wet coating can obtain a heat radiation effect due to the graphene. However, due to the heat conduction characteristic in the horizontal direction of the graphene itself, The effect is inevitably limited in two dimensions, and the price of the electronic product is increased due to the high price, so that it is difficult to apply it to general purpose.

In addition, when the grapevine is used in the form of a sheet, it is adhered by using an adhesive tape, so that a gap due to the adhesive tape is generated to lower the heat transfer effect. When the area is widened, there was.

In addition, other heat-radiating paints have a problem that when the surface is not smooth and a phenomenon such as folding occurs, a crack occurs and the function of the heat-dissipating paint can not be exhibited.

Since the heat pipe used as the conventional heat dissipating device is formed by injecting a heat medium therein, the heat medium must be smoothly moved, so that it is not easy to install the heat medium at a bent portion, It is difficult to achieve the ultra-thin type because the thickness of the electronic device is limited because the design must be designed to have a minimum thickness of 0.4 mm in order to operate the heat pipe normally. Therefore, There is a problem in that the heat dissipating sheet is further attached to the heat dissipating sheet in order to diffuse the heat dissipating area.

It is an object of the present invention to solve the problems described above and to provide a carbon fiber material which is used as a filler by mixing a carbonaceous material with another thermally conductive material and has an excellent heat radiation effect while minimizing the amount of the carbonaceous material, The present invention provides a heat spreader in which a paint having an effect is coated on a thermally conductive base to prevent economic and structural difficulties in the realization of an ultra slim electronic product and to prevent the heat dissipation function from being lost even in the case of damage. And to provide a heat spreader in which the restriction of electronic product design is not caused.

In addition, in order to improve the heat conduction effect by eliminating the thermal conductivity direction and improving the contact area between the fillers by using metal oxide, ceramic, or the like having excellent heat transfer characteristics with respect to the two-dimensional thermal conductivity property by the carbon- There is a purpose.

In order to achieve the above object, the present invention is characterized in that it comprises a polyurethane resin, a wetting agent or a dispersion stabilizer, a leveling agent, a defoaming agent, a solvent comprising a flowability adjusting additive, In a heat spreader coated on a plate-shaped thermally conductive base.

The filler may be selected from the group consisting of Ag, Cu, Al, Mg, Si, Zr, MgO, Al ₂ O ₃ , One selected from the group consisting of tin (SnO), silicon carbide (SiC), nitride (Si ₃ N ₄ , AlN, BN), graphite, graphene, carbon nanotubes (CNT) , It is preferable to use a mixture of one or a mixture selected from the group consisting of silicon carbide (SiC), grapevine, graphene and carbon nanotubes with other filler except for the carbonaceous material, and the carbonaceous material has an average particle diameter of 0.01 Mu m to 10 mu m are used, and the other fillers having an average particle diameter of 0.01 mu m to 1 mu m are used.

According to the present invention having the above-described structure, it is possible to provide a heat spreader having a thickness of 0.3 mm or less by coating a coating composition having an excellent heat radiation effect at low cost on a plate-shaped base, The structural and morphological difficulties do not occur, the stability against heat is enhanced, the cost is reduced, and the heat dissipation function is not lost even by the stamp damage, so that the electronic product can be stably operated.

In addition, since it is formed in the form of a plate, it can be cut or deformed into various shapes so that it can be applied to any kind of electronic products. Therefore, not only the structural design restriction is caused in the design of electronic products, .

Another object of the present invention is to improve the heat conduction effect by eliminating the direction of heat conduction and improving the contact area between the fillers by using the metal oxide, ceramics or the like in combination with the horizontal heat conduction characteristic by the carbon-based material.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a drawing showing the results of physical property test of the heat radiation coating composition of the present invention
2 is a view showing a result of measurement of thermal conductivity of the heat radiation coating composition of the present invention
3 is a view showing a thermally conductive measuring instrument of the present invention
4 to 5 are photographs showing samples and equipment for measuring heat transfer characteristics of a heat spreader according to the present invention
6 is a view showing heat transfer characteristics of a heat spreader according to the present invention;

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

The heat spreader according to the present invention comprises a solvent composed of a polyurethane resin, a wetting agent or a dispersion stabilizer, a leveling agent, a defoaming agent, and a flow control additive, and a filler which is dispersed in the solvent and dispersed and has an average particle size of 0.01 탆 to 10 탆 Is coated on a plate-shaped thermally conductive base and dried.

In the embodiment of the present invention, a copper plate having a thickness of 0.2 mm is used. In addition to the copper plate, a metal plate made of silver, aluminum, PCB, FPCB or the like is used as the base. Anything having a city is possible.

The wetting agent or dispersion stabilizer is used as an additive for wetting and dispersing the non-aqueous coating material. The wetting agent or the dispersion stabilizer is used in an amount of 0.5 to 2% based on the total weight of the heat dissipating coating composition. In the present invention, CFC-6010 (manufactured by Cheongwoo CFC) It is used for preventing the re-aggregation of the filler after dispersing and dispersing the filler by using a trade name CFC-6330N (manufactured by Cheongwoo CFC Co., Ltd.). Examples include polymethyl acrylate (PMA), xylene, butylacetate, and solvent (DIBK / BC / Anone).

The leveling agent comprises a polymeric acrylic ester copolymer as a main component and has a solid content of 52 to 2% and is used in an amount of 0.1 to 2% by weight based on the total weight of the coating composition to improve the leveling effect of the coating composition, (CFC-89 manufactured by Cheongwoo CFC Co., Ltd.) is used in the embodiment of the present invention.

The antifoaming agent (surfactant) is a modified polysiloxane copolymer, a modified olefin compound having a solid content of 98 2%, and a polyether-modified polysiloxane having a solid content of at least 94%, and is used in an amount of 0.1 to 2% by weight based on the total weight of the coating composition. And CFC-144B (manufactured by Cheongwoo CFC Co., Ltd.) under the trade name of CFC-166H (manufactured by Cheongwoo CFC Co., Ltd.), and the function of facilitating wetting of the substrate upon coating the substrate. , And trade name CFC-733E (manufactured by Cheongwoo CFC Co., Ltd.).

The flowability-adjusting additive is mainly composed of a low molecular weight modified urea having a solid content of 52 ± 2% and is used in an amount of 0.1 to 2% by weight based on the total weight of the coating composition to ensure fluidity of a highly viscous material. In the examples of the present invention, CIMA- (Manufactured by Cheongwoo CFC Co., Ltd.) is used.

The urethane solvent having such a constitution is used in an amount of 40 to 70% by weight based on the total weight of the coating composition.

The filler is silver (Ag), copper (Cu), aluminum (Al), magnesium (Mg), silica (Si), zirconium (Zr), magnesium oxide (MgO), aluminum oxide (Al ₂ O _3), tin oxide (SnO), silicon carbide (SiC), a nitride _{(Si 3 N 4, AlN,} BN), Gras pipe, graphene, a first alternative in CNT dog or to use a mixture of these, the carbon-based material of silicon carbide (SiC ), Grapevine, graphene, and CNT, or a mixture thereof and other fillers other than the above are preferably used, and the carbonaceous material having an average particle diameter of 0.01 to 10 탆 is used, and the other fillers have an average And a particle diameter of 0.01 mu m to 1 mu m is used.

The coating composition may be applied to a substrate composed of any one of aluminum, copper, and a metal alloy. In the coating process, the coating composition may contain 50-90% by weight based on the total weight, 3-20% by weight of a diluent, -50% by weight.

The diluent may be selected from the group consisting of MPA, butyl acetate (BA), alkyl (Alkyl) and benzene, or a mixture thereof. The curing agent may be one selected from aliphatic dihydric alcohols, polyisocyanates, And mixtures thereof.

In the case of using silicon carbide (SiC) and silicon nitride (Si ₃ N ₄ ) particles having a size of 1 to 3 탆, the particle size after coating is preferably 0.1 to 0.01 탆 .

The grapple is preferably 1 to 10 mu m in size, and the surface roughness after coating is poor when it is 10 mu m or more.

In addition, the particle size of the filler is adjustable based on the surface roughness, the thickness and space of the substrate used, and the like, but it is preferably 1 탆 to 0.01 탆.

Then, the solvent and the filler are stirred at room temperature for 8 hours.

Embodiments of the present invention thus configured will be described in more detail below.

[Comparative Example]

The aluminum plate is 12.5 mm in width, 7 mm in length and 1 mm in height, and the result of thermal conductivity measurement (TPS 500S HOT-DISK method) is 135.5 W / mK.

[Example 1]

(50% of the total weight of the coating composition) of a urethane solvent (2 L), SiC (500 g), AlN (300 g), BN (200 g) (TPS 500S HOT-DISK method) of 142.5 W / mK after coating the aluminum original plate of Comparative Example 1 at 80 ° C for 30 minutes, and the coating properties were good And surface roughness was confirmed to be poor.

[Example 2]

(2 liter), AlN (500 g), BN (300 g), MgO (200 g) diluent (within 10% of the total volume) and curing agent (50% of the total volume). After stirring at room temperature for 1 hour to 1 hour and 30 minutes, The coating was applied to an aluminum original plate of Comparative Example 1 and cured at 80 ° C for 30 minutes. The result of the thermal conductivity measurement (TPS 500S HOT-DISK method) was 144 W / mK. The coating property was good and the surface roughness was good .

[Example 3]

Urethane solvent (2 ℓ), AlN (500 g), BN (300 g), MgO (200 g), Grapepipe (500 g) diluent (within 10% of total capacity) After 30 minutes of stirring, the coating was applied to an aluminum original plate of Comparative Example and cured at 80 ° C for 30 minutes. The thermal conductivity was measured (TPS 500S HOT-DISK system) at 162 W / mK. The coating property was good and the surface roughness was normal.

[Example 4]

The coating and the surface roughness were good and the thermal conductivity was improved by about 10% at 162 W / mK - > 179 W / mK when the stirring time was operated using a ball mill for 8 hours to 10 hours under the same conditions as in Example 3.

Therefore, when the mixture is stirred for 8-10 hours using a ball mill as described above, SiC, Si ₃ N ₄ , AlN, BN, MgO, Al ₂ O _{3 and} grapevine materials can be used as fillers.

[Example 5]

The aluminum original plate of Comparative Example 1 was set to 50 ° C., and the equipment was constructed as shown in FIG. 3, and the measurement material was placed on the heat source plate, and the measurement was made at 40.9 ° C. for 30 minutes and 40.9 ° C. for 45 minutes 2, No. 1).

[Example 6]

The sample of Example 1 was set to 50 캜, and the temperature of the sample was 43.5 캜 for 30 minutes and 44.8 캜 (number 2 of Fig. 2) after 45 minutes.

[Example 7]

The plastic raw material (cell phone case) was set at 50 ° C (homology), and the result of measurement at 30 minutes and post-temperature was 41.1 ° C, and at 45 minutes elapsed, 41.5 ° C (number 3 in FIG.

[Example 8]

The sample of Example 1 was set to 50 캜 (homology), and the result of measuring the temperature around 30 minutes and the post-temperature was 42.3 캜 and the elapsed time of 45 minutes was 42.3 캜 (No. 4 in Fig.

On the other hand, as a result of the physical properties test of the heat radiating coating composition of the present invention, it was confirmed that all of the items of hardness adhesion, impact resistance, corrosion resistance, alkali resistance, heat resistance, 4.

[Example 9]

The aluminum disk of Comparative Example 1 was prepared by stirring 200 g of a urethane solvent, 40 g of SiC, 35 g of AlN, 30 g of BN, 20 g of MgO, 10 g of Al ₂ O ₃ , 30 g of a grapipe, 30 g of a diluent, and 30 g of a curing agent at room temperature for 1 hour to 1 hour and 30 minutes. And a plastic plate, and cured at 80 DEG C for 30 minutes. After setting at 50 DEG C and 45 minutes at room temperature, the temperature of the surface of the substrate was measured, and a known grapheme sheet or a vapor-deposited heat- The result of measuring the temperature after attaching the copper plates coated with the heat radiating coating composition (? Paint) of the present invention or the copper plates coated with the heat radiating coating composition (? Paint) of the present invention shows that the coating composition of the present invention has excellent thermal conductivity have.

Setting the measurement temperature at 50 ° C is based on the assumption that the internal heat generation of the smartphone is set at 50 ° C, and there is not a correlation between the measurement temperature and the heat radiation effect.

On the other hand, in the above, SiC has a high hardness, a high heat resistance, a high corrosion resistance and a high thermal conductivity, and a relatively low coefficient of thermal expansion.

Aluminum nitride (AlN) has very high thermal conductivity and good electrical insulation properties.

Boron nitride (BN) has a high thermal conductivity and a large thermal shock resistance. It is resistant to cracking or breakage even when it is repeatedly cooled to a temperature of about 1500 ° C., and most organic solvents are excellent in corrosion resistance, and gold, silver, Does not react with melts such as aluminum, zinc, lead, tin, nickel, manganese, germanium, gallium, silicon and glass and is excellent in high temperature lubricity, low in friction coefficient, light in weight and excellent in machinability.

Grape pipe has the characteristic of increasing the strength up to about 2 times as the temperature increases, and is excellent in electrical conductivity, corrosion resistance to chemicals, light weight, and excellent workability.

In order to confirm the heat radiation effect of the heat spreader according to the present invention, as shown in FIG. 4, a conventional heat pipe (applied to Samsung Galaxy S8 smartphone) (Comparative Example 4), copper plates (Comparative Examples 1 to 3) The heat spreader of the present invention coated with a heat radiating coating material (Inventive Invention 1 to 3) was inserted into an inserting groove formed in an aluminum (Al) original plate to measure the thermal conductivity.

The heat spreader of the present invention was manufactured by coating a heat radiating paint with a thickness of 30 μm or less on the outer circumference of a copper copper plate having a thickness of 0.2 mm.

The samples thus prepared were heated to 50 DEG C using an experimental equipment as shown in Fig. 5, and after 20 minutes passed, the temperature was measured once at four points (Sp1 to Sp4) of the heat source and the thermal diffusion part. A thermal conductivity grease of 11 W / mK was further used to increase the thermal conductivity between samples and to block the air gap. At this time, the measurement site was maintained at 22 ° C.

As a result, as shown in FIG. 6, in Comparative Examples 1 to 3, in which only the copper plate is used as a whole in the positions S1, S2, S3 and S4 spaced from the heat source and the contact portion, This difficulty can be seen.

As compared with Comparative Example 4 which is a conventional heat pipe, the heat spreaders according to the present invention, which are the heat spreaders of the present invention, can be confirmed that the temperature spread of the heat spreader of the present invention The heat spreader of the present invention shows a high heat transfer rate.

Particularly, in the case of the sample having the largest area of the heat source portion (Invention 3), the thermal diffusion rate is improved as the contact area between the heat source and the heat source is increased.

In the case of a sample of the same type, the heat is passed through the irregularities on the rim and the heat is brought into contact with the air through the irregularities, so that the temperature of S2, which is the point where the irregularities have passed, Which is lower than that of the first embodiment of the present invention, which is not formed. It can be seen that it is advantageous that unevenness is formed on the edge when used as a heat dissipation material.

The heat spreader of the present invention can be formed to have a thickness of several micrometers or less and can be made ultra thin and can be bent and bent. Therefore, it is possible to provide a heat spreader having a very thin shape or a curved surface such as a smart phone, a wearable terminal, It is possible to increase the design freedom of these products and improve the price competitiveness.

Claims (4)

A heat dissipation coating composition comprising a solvent comprising a polyurethane resin, a wetting agent or a dispersion stabilizer, a leveling agent, a defoaming agent, and a flow control additive, and a filler dispersed in the solvent and dispersed and having an average particle size of 0.01 탆 to 10 탆, Wherein the heat spreader is applied onto a plate-shaped thermally conductive base and then dried. According to claim 1 wherein in the filler is silver (Ag), copper (Cu), aluminum (Al), magnesium (Mg), silica (sI), zirconium (Zr), magnesium oxide (MgO), Al ₂ O ₃ , A heat spreader characterized by using one selected from tin oxide (SnO 2), silicon carbide (SiC), nitride (Si ₃ N ₄ , AlN, BN) . The filler according to claim 2, wherein the filler is a mixture of one or a mixture selected from silicon carbide (SiC), grapevine, graphene and CNT, and other fillers, Wherein the filler having an average particle diameter of 0.01 to 10 mu m is used and the other fillers have an average particle diameter of 0.01 to 1 mu m. The heat spreader according to claim 1, wherein the heat spreader has a concavo-convex shape.

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