JP3345986B2 - Graphite heat conductor and cold plate using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graphite heat conductor, and more particularly to a method for controlling heat generated from various electronic devices, electronic components thereof, high-density semiconductors, etc., that is, for performing heat radiation and cooling. The present invention relates to a graphite heat conductor used for controlling the heat of a heating element such as an electronic device mounted on a spacecraft such as a spacecraft or an artificial satellite.

[0002]

2. Description of the Related Art In recent years, how to control heat generated from high-density integrated semiconductors constituting various electronic devices,
It is becoming very important how to perform the cooling and heat radiation.

For example, the problem of generated heat in high-density semiconductors is important, and how to cool them is becoming one of the points in designing computer equipment.

While effective cooling requires a good combination of convection, radiation, and conduction, cooling small parts, such as high-density semiconductors, involves dissipating heat primarily through heat conduction. Guide to the low temperature part and cool.

[0005] Therefore, in order to cool the heat from a heating element of an electronic device or the like, it is necessary to provide a means for transferring the heat to a radiator provided so as to be exposed outside the electronic device. As one of the above, a cold plate is provided for each heating element.

At present, as a cold plate, for example, a configuration shown in FIGS. 11 to 14 is considered.

FIG. 11 shows a configuration in which the heat generating element 4 is directly installed on the heat receiving element 1, and FIG. 12 shows a cross section taken along line XX.

FIG. 13 shows a configuration in which a bar-shaped metal 6 such as aluminum is provided between the heating element 4 and the heat receiving element 1.
FIG. 14 shows the YY cross section.

In any structure, the principle of heat radiation is as follows.
The heat generated by electronic devices is transferred to the cold plate in the spacecraft.

Specifically, a pipe 6 through which a coolant such as water or freon flows in and a pipe 7 through which the coolant flows out are provided at the end of the heat receiving body 5.

A fin 9 which also serves as a flow path is provided inside the heat receiving member 5, and a refrigerant is circulated between an external radiator and a cold plate by a pump (not shown).

The heat generated by the heating element 8 is conducted to the heat receiving element 5 directly or through the metal rod 10 and is transferred to the refrigerant inside the heat receiving element 5.

The heat of the refrigerant is radiated to outer space by heat radiation by an external radiator.

Conventionally, a metal material having excellent heat conductivity has been used for such a cold plate.

[0015]

However, silver, which has the highest thermal conductivity among such metallic materials, is expensive, while relatively inexpensive, such as iron and aluminum, which are relatively inexpensive.

Copper is excellent among these, but has the disadvantage that its heat conduction (403 W / m · K) is not sufficient and that it is heavy.

Therefore, development of a new material having excellent thermal conductivity is indispensable for more effective cooling and heat radiation.

In recent years, technical progress in the aerospace field has been remarkable, and under such conditions, how to effectively cool and radiate electronic equipment has become a major issue.

In the first place, since the space and space are vacuum and weightless, heat transfer by the convection phenomenon of air cannot be expected.

However, when air exists in the spacecraft, it is possible to cool the heat source by a forced air cooling method using a fan. However, since the heat radiating place is in the outer space, the final cooling is required. You have to rely on heat radiation.

However, the forced cooling method using the fan has a problem that the power consumption increases.

When a heating element is directly installed on a heat receiving element, a cold plate is required for each heating element, which increases equipment costs and makes it difficult to move electronic equipment freely.

When a metal bar is used, the weight increases because the metal bar is installed for each electronic device. Further, it is difficult to move and maintain the electronic device with an inflexible device such as a metal bar. It is.

Therefore, recently, it has been proposed to use a graphite film which is lighter than metal and has excellent heat resistance as a heat conductive material used for such a cold plate.

The thermal conductivity of such a conventional graphite material is 200 to 500 for single crystal graphite.
W / cm · K, with other graphite, at most 20 ~
It was about 100 W / cm · K.

Therefore, conventional graphite materials other than single crystals were not practically usable as heat dissipating materials.

However, the thermal conductivity of single crystal graphite is 200 to 500 W / m · K as described above, and it is considered that such excellent thermal conductivity can be actually realized by film-like graphite. The result should be a very good cold plate.

However, it has been technically difficult to produce a single-crystal graphite film having such high performance by the conventional method.

In order to realize a graphite film having high thermal conductivity, it is necessary that the crystallites of graphite are large and their orientation is high. It was difficult to realize a simple structure.

For example, there has been a conventional graphite film produced from natural graphite by an expanding method.

However, the thermal conductivity of the graphite film produced by such a method is 20 to 100 W / m.
-It was in the range of K, and its thermal conductivity was lower than that of metals such as aluminum.

Further, since the acid used in the manufacturing process of the graphite film remains, there has been a problem such as corrosion of metal due to leaching of the residual acid.

Further, even if such a graphite film having high thermal conductivity can be realized, various measures are considered to be necessary when actually using it as a thermal conductive material.

This is because the high thermal conductivity of graphite is essentially two-dimensional conduction, and the thermal conduction in the direction parallel to the graphite surface is large, but the thermal conduction in the direction perpendicular to the film surface is 1 / there. It is about 100.

Therefore, how to effectively utilize such conduction and improve the film strength,
Some considerations arise.

An object of the present invention is to solve the above-mentioned problems, and to make effective use of the two-dimensional thermal conductivity of graphite to radiate heat from a heating element such as an electronic device. An object of the present invention is to provide a highly heat-conductive graphite heat conductor which is efficiently performed, is light in weight, has flexibility, and facilitates maintenance of electronic devices and the like.

[0037]

Means for Solving the Problems In order to solve the above problems, the present invention comprises a graphite film obtained by heat treatment of a predetermined polymer film and having a thermal conductivity of 500 W / m · K or more ; One of the graphite films
Cut into the strip to make a strip,
It is a graphite heat conductor that bundles a part .

Further, the graphite film is made of epoxy
Resin, polyimide, polyamide imide, polyamide,
Enol resin, polycarbonate, polyester, poly
Benzimidazole, ABS, polystyrene or poly
Graph showing a laminated structure with a polymer layer containing ethylene
It may be an agitated heat conductor .

Further, the graphite film surface
In addition, a metal layer may be formed as a reflective film .

Further, it is obtained by carbonizing a predetermined polymer film by itself and laminating a plurality thereof, or by laminating a plurality of predetermined polymer films and carbonizing, and then performing graphitization under mechanical pressure. A graphite block, the graphite surfaces of which are oriented parallel to each other, a graphite block having thermal conductivity in the direction of the graphite surface, and a predetermined polymer film cut into strips or fibers are oriented in one direction. A carbon block and a graphite block obtained by performing carbonization and graphitization under mechanical pressure, the graphite block having thermal conductivity in the direction of the orientation, or a predetermined height wound substantially concentrically. Graph obtained by carbonizing and graphitizing a molecular film under mechanical pressure A site block, graphite block having thermal conductivity in the axial direction of the concentric circles
Each graphite block has thermal conductivity
Cut with a thickness of 5 mm or less on a plane perpendicular to the direction
As a result , a graphite thermal conductor having high thermal conductivity in the thickness direction may be used.

The predetermined polymer film of the graphite heat conductor of the present invention is selected from polyoxadiazole, aromatic polyimide, aromatic polyamide and polyparaphenylenevinylene having a thickness of 400 μm or less. It is preferable that the polymer film is obtained by heat-treating the polymer film at a temperature of at least 2400 ° C.

[0042]

[0043]

According to the present invention, a thermal conductivity of not less than 500 W / m · K obtained by heat treatment of a polymer film, 2.26 g / m.
By using a high-purity graphite film having a density of not more than cm ^{3 and} containing less impurities as a heat conductive material, heat is efficiently released.

Further, by combining a graphite film with a polymer film, a metal film, or the like, the mechanical strength is increased, and unnecessary temperatures are radiated while maintaining the temperature of a required portion, so that heat is radiated more efficiently.

A graphite block obtained from a plurality of polymer films has a high thermal conductivity and efficiently cools a high-density semiconductor or the like.

[0046]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The heat conductor of the present invention is a graphite film obtained from a special polymer film having a certain thickness or less, which is different from a graphite film obtained by a conventional method. And the fact that it has been newly found that there is no metal corrosion due to residual acid, which was a problem to be solved conventionally.

Specifically, polyoxadiazole having a thickness of 400 μm or less, aromatic polyimide,
Aromatic polyamide, using at least one type of polymer film selected from polyparaphenylene vinylene, by heat treatment at a temperature of at least 2400 ℃ or more, has excellent thermal conductivity as described below, metal It is a graphite heat conductor that does not cause corrosion.

As the polymer, polybenzothiazole, polybenzobisthiazole, polybenzoxazole, polybenzobisoxazole, polyamideimide, polyphenylenebenzimitazole, polyphenylenebenzobisimidazole, polythiazole and the like can also be used. It is.

First, in the present invention, 400
The film having a thickness of μm or less is preferably used, because, when a raw polymer film having a thickness of 400 μm or more is used, a high-quality graphite film or a heat-treated graphite film of the present invention can be used. Obtaining a graphite block is difficult, in that only a battered graphite film or graphite block without uniformity is obtained.

Further, the thermal conductivity of a graphite film or a graphite block obtained from such a film is generally 500 W / m · K or less, which is not suitable as a high-performance heat conductor.

Therefore, the range of the thickness of the raw material polymer film to which the production process according to the present invention is effectively applied is 400 μm.
It is considered to be within m or less.

Next, in the present invention, the final highest processing temperature needs to be 2400 ° C. or more.

This is because when the processing temperature is 2400 ° C. or less, the obtained film or block is hard and brittle.

However, heat treatment in a temperature range of at least 1600 ° C. needs to be performed in an inert gas at normal pressure or under pressure.

Specifically, when the thickness of the raw material polymer film is less than 100 μm, heat treatment under normal pressure is often sufficient, but when the thickness is 100 μm or more, the pressure It is necessary to perform heat treatment.

[0056] The size of the pressure required at that time may vary depending on the thickness of the film, it is generally preferred that a pressure of 50 Kg / cm ² from 0.1 Kg / cm ^2.

If the produced graphite film is subjected to a rolling treatment as required, a tougher and more flexible graphite film can be obtained.

In summary, according to the present invention, a graphite film obtained by using a polymer film mainly having a specific molecular structure and having a thickness within a specific range can provide 500 W / m · It has an excellent thermal conductivity of at least K and a density of 2.26 g / cm.
Because it is much lighter than ordinary metal at ³ or less,
In terms of the performance index of the heat conductor, a heat conductor exhibiting much better heat radiation characteristics than that using a conventional metal can be obtained.

Further, the graphite film according to the present invention not only has a high flexibility but also has a characteristic that it can be cut and processed freely with scissors or a knife.

The graphite film, which is the heat conductor of the present invention, usually has a thickness of 10 to 50 μm, but even if the thickest polymer film, 400 μm, is used as the raw material, The thickness of the obtained graphite film is about 200 μm, and the strength is not sufficient.

On the other hand, the high thermal conductivity of graphite
It occurs in the surface direction of the graphite film, and the thermal conductivity in the thickness direction of the surface is about 1/100 of that.

Therefore, by forming these graphites into a laminated structure with a suitable polymer, the strength of the film can be improved, and the two-dimensional conduction characteristics can be more remarkably utilized. Becomes

FIG. 1 shows a configuration diagram of such a graphite-polymer composite heat conductor. Polymers that can be used for such purposes include epoxy resins, polyimides,
A wide range of polymers such as polyamideimide, polyamide, phenolic resin, polycarbonate, polyester, polybenzimidazole, ABS, polystyrene, and polyethylene can be used, and particularly, polyimide and polyamideimide having high heat resistance are effective.

When the polymer is thermosetting, the polymer or its precursor dissolved in a solvent is coated on a graphite film 1 and dried by pressing to form a polymer film 2. This step may be repeated in order.

In the case of a thermoplastic polymer, a polymer layer and a graphite film may be alternately laminated and then thermocompression-bonded.

The composite of a graphite film and a metal is very effective in compensating for the drawback of graphite being two-dimensional conductive.

Further, when the outermost layer is a metal layer,
This layer effectively works as a reflection film for reflecting radiant heat.

Such a composite of a graphite film, a polymer layer and a metal layer improves the strength of graphite,
It is very effective for utilization of dimensional conductivity and reflection of radiant heat.

FIG. 2 is a structural view of such a composite with the graphite film 1, the polymer layer 2 and the metal layer 3.

In this composite, the graphite film 1, the polymer layer 2, and the metal layer are alternately laminated, and a metal layer 3 is provided as the outermost layer.

The outermost metal layer 3 functions effectively as a radiant heat reflecting film, and copper, aluminum, silver, etc. can be used effectively as the metal.

The above-described heat conductor made of a graphite film, or a heat conductor made of a composite of a graphite film and a polymer, a metal, or the like, may be used in an outer space, such as an electronic device in a spacecraft. It is possible to efficiently radiate heat from the heating element, and to realize the weight reduction and cost reduction of the spacecraft.

Further, since the heat conductor has sufficient flexibility, maintenance of electronic equipment and the like can be facilitated.

The heat conductivity of the graphite film is 2
In order to compensate for the drawback of being two-dimensional, the raw material polymer film is carbonized by laminating a single or a plurality of films, or a plurality of carbonized films are laminated after carbonization, and further graphitized under mechanical pressure, and the graphite surface is formed. May be produced in parallel to form a graphite block.

If the thus obtained graphite block is cut along a plane perpendicular to the graphite plane, a graphite block having high thermal conductivity only in one plane direction can be obtained.

FIG. 3 shows a configuration diagram of such a graphite block. This graphite block is used as a heat conductor by being installed such that one end of the high heat conduction surface is in contact with a heat source such as a high-density semiconductor.

Also, if necessary, the end or the whole
It is also possible to insulate with SiC (silicon carbide) or the like.

The block-shaped graphite thermal conductor having thermal conductivity only in one direction as described above is described below with reference to FIG.
Alternatively, it can be manufactured as shown in FIG.

First, in FIG. 4, a polymer film cut into strips or fibers is oriented in one direction, and then carbonized and graphitized under mechanical pressure.

Next, this is cut along a plane perpendicular to the orientation axis to obtain a graphite block having high thermal conductivity in only one axis direction.

Further, as shown in FIG. 5, even if the polymer film wound concentrically was carbonized and graphited under mechanical pressure, similarly, high thermal conductivity was imparted only in the uniaxial direction. A block-shaped graphite thermal conductor can be produced.

Hereinafter, the graphite heat conductor of the present invention will be described more specifically with reference to Examples.

Example 1 50 μm in thickness and 500 m in width
m, 700 mm long polypyromellitimide (Dup
ont Kapton H film) was preheat treated at 1000 ° C and then at 3000 ° C.

After that, it is rolled by passing between two rollers to have a thickness of 40 μm, a width of 400 mm, and a length of 560.
mm was obtained.

Then, as shown in FIG. 6, a cut was made on one side of the graphite film to form a strip.

Next, as shown in FIG. 7, the strip-shaped portions were bundled together, and as shown in FIG. 8, a flexible heat insulating material 4 was wound around the bundled portions.

The heat conductor of the graphite film thus formed is placed under a heating element 8 such as an electronic device as shown in perspective in FIG. 9, and an end of a portion where the graphite films 2 are bundled is attached. , As shown in FIG.

The density and thermal conductivity of the graphite thermal conductor obtained in this example were compared with those of conventionally used metals, and the results are shown in Table 1.

[0089]

[Table 1]

According to this comparison result, the graphite thermal conductor has a characteristic value about 1/2 or less in density and about 3.3 times or more in thermal conductivity as compared with aluminum.

Furthermore, compared to silver and copper, which have excellent thermal conductivity, they have characteristic values of a density of about 1/9 or less and a thermal conductivity of about 2.0 times.

For this reason, when compared with aluminum, 6.0
More than double the efficiency. According to the study of the present inventors,
Such an improvement in the properties is achieved when the thickness of the raw material polymer is 400 μm.
m or less.

In the portion connecting the heat generating element 8 and the heat receiving element 5, the heat insulating material 4 and the graphite therein have flexibility, so that the electronic equipment can be easily moved and the maintenance is easy.

Further, when a plurality of heating elements 8 are provided, a portion for connecting several heating elements and the heat receiving element can be collected, for example, into one heat receiving element, so that the number of heat receiving elements can be reduced. Thus, the weight of the cold plate itself can be reduced and the equipment cost can be reduced.

According to the heat conductor of this embodiment, heat can be efficiently radiated from the heating element such as electronic equipment. When the heat conductor is used in a spacecraft, the weight and cost of the spacecraft can be reduced. Can be realized.

Comparative Example 1 500 μm in thickness and 500 m in width
m, a polyimide film with a length of 700 mm at 1000 ° C
And then under a pressure of 50 kg / cm ² at 28
Heat treatment was performed at 00 ° C. After that, it is rolled by passing between two rollers, and has a thickness of 400 μm, a width of 400 mm,
A 560 mm long graphite film was obtained.

However, the graphite film thus obtained was ragged and non-uniform, and had a low strength.

The thermal conductivity of the graphite film was very low at 20 W / m · K.

(Example 2) Thickness 50 μm, width 500 m
m, a polyoxadiazole having a length of 700 mm (POD manufactured by Furukawa Electric Co., Ltd.) is subjected to a preliminary heat treatment at 1000 ° C.
Heat treatment was performed at 900 ° C.

Thereafter, the film is rolled by passing between two rollers to have a thickness of 35 μm, a width of 400 mm, and a length of 560.
mm was obtained.

Then, this graphite film was processed in the same manner as in Example 1, placed under a heating element such as an electronic device in the same manner, and the end of the portion where the graphite films were bundled was used as a heat receiving element. Connected.

The thermal conductivity of the graphite film thus evaluated was 750 W / m · K.
Excellent heat dissipation characteristics were exhibited.

According to the study of the present inventors, such characteristics were maintained until the thickness of the raw material polymer was about 400 μm or less.

(Example 3) A graphite film was prepared by the method described in Example 1, and a polyimide precursor (Trenice manufactured by Toray Industries, Inc.) was added to the film.
It was applied to a thickness of 0 μm.

Then, after drying under reduced pressure, 20 films whose imidization had not sufficiently progressed were laminated, and subjected to thermocompression bonding.

In this case, the temperature is 300 ° C. and the pressure is 10 K
g / cm ² . A thermocouple was placed inside and on the surface of the film thus obtained, the edge of the film was irradiated and heated with an infrared lamp, and one end was cooled at 0 ° C.

As a comparative experiment, the temperature was measured by a thermocouple using a polyimide film having the same thickness.

As a result, in the graphite composite material according to the present example, when the film surface temperature was 200 ° C., the internal temperature was 52 ° C.

On the other hand, in the case of a polyimide film, when the temperature on the film surface is 200 ° C., the internal temperature is 1 °.
08 ° C.

From the above, it was found that the graphite composite film according to this example had an excellent heat radiation effect.

Example 4 A graphite film was prepared by the method described in Example 1, and then a solution-like polyimide precursor (Trenice, manufactured by Toray Industries, Inc.) was applied to the surface of the film to a thickness of 10 μm. did.

After drying under reduced pressure, 20 films which had not yet undergone sufficient imidization were laminated and heated and pressed.

In this case, the temperature is 300 ° C. and the pressure is 10 K
g / cm ² . Aluminum was deposited on the surface of the obtained film in a thickness of about 2 μm.

A thermocouple was placed inside and on the surface of the thus obtained film, the end of the film was irradiated with an infrared lamp and heated, and one end was cooled at 0 ° C.

As a comparative experiment, the temperature was measured with a thermocouple using polyimide films having the same thickness.

As a result, when the temperature of the film surface was 200 ° C. in the graphite composite material according to the present invention,
The internal temperature was 44 ° C.

On the other hand, in the case of a polyimide film, when the film surface temperature is 200.degree.
02 ° C.

As a result, it was found that the graphite composite film of this example had an excellent heat radiation effect.

The aluminum layer formed by vapor deposition on the surface of the graphite film can be provided on the polymer layer side as shown in FIG. 2 or on the opposite graphite film side depending on the purpose. It is also possible, of course, in some cases to form both of them and in the intermediate region inside.

(Example 5) Polypyromellitimide (Kapton H film manufactured by Dupont) having a thickness of 50 μm was added to 1
000 sheets were laminated and subjected to a preliminary heat treatment at 1000 ° C.

Then, the block after the preliminary processing is taken out, and
Heat treatment was performed at 2900 ° C. using an ultra-high temperature hot press.

A graphite block was prepared by applying a pressure of 300 kg / cm ² at 2900 ° C. for one hour.

Thus, a graphite block having a thickness of 10 mm, a width of 20 mm and a length of 20 mm was obtained.

Next, this block was cut to a thickness of 5 mm on a surface perpendicular to the graphite surface, and a thickness of 5 mm and a width of 10 m
m and a block having a length of 20 mm were obtained.

A thermocouple was placed under the graphite block, and the graphite surface was heated with an infrared heater.

As a comparative experiment, copper blocks of the same size were heated under the same conditions. As a result, when the thermocouple installed under the graphite block was at 100 ° C., the thermocouple under the copper block was at 83 ° C., demonstrating the excellent thermal conductivity of the graphite block according to the present embodiment. .

Example 6 A 50 μm thick polypyromellitimide (Kapton H film manufactured by Dupont) was cut into a length of 50 mm and a width of 1 mm, and was cut in a graphite box in a certain direction to obtain 50 kg / cm ² . Preliminary heat treatment was performed at 1000 ° C. while applying pressure.

Then, the block obtained after the preliminary treatment was taken out and heat-treated at 2900 ° C. using an ultra-high temperature hot press.

A graphite block was manufactured by applying a pressure of 300 kg / cm ² at 2900 ° C. for one hour.

Thus, a graphite block having a thickness of 10 mm, a width of 20 mm and a length of 50 mm was obtained.

Next, this block was cut to a thickness of 5 mm on a surface perpendicular to the graphite surface, and a thickness of 5 mm and a width of 10 m
m and a block having a length of 20 mm were obtained.

A thermocouple was set under the graphite block, and the graphite surface was heated with an infrared heater.

As a comparative experiment, copper blocks of the same size were heated under the same conditions. When the thermocouple placed under the graphite block was at 100 ° C., the thermocouple under the copper block was at 85 ° C., demonstrating the excellent thermal conductivity of the graphite block according to the present example.

Example 7 A 50 μm thick polypyromellitimide (Dupont, Kapton H film) was wound around a concentric circle and packed in a graphite box having a length of 50 mm and a width of 20 mm.

Thereafter, a preliminary heat treatment was performed at 1000 ° C. while applying a pressure of 50 kg / cm ² .

Then, the block obtained after the pretreatment was taken out and heat-treated at 2900 ° C. by using an ultra-high temperature hot press.

A pressure of 300 kg / cm ² was applied at 2900 ° C. for one hour to produce a graphite block.

Thus, a graphite block having a thickness of 10 mm, a width of 20 mm and a length of 50 mm was obtained.

Next, this block was cut to a thickness of 5 mm on a surface perpendicular to the graphite surface, and a thickness of 5 mm and a width of 10 m were cut.
m and a block having a length of 20 mm were obtained.

A thermocouple was set under the graphite block, and the graphite surface was heated with an infrared heater.

As a comparative experiment, copper blocks of the same size were heated under the same conditions. When the thermocouple installed under the graphite block was at 100 ° C., the thermocouple under the copper block was at 878 ° C., demonstrating the excellent thermal conductivity of the graphite block according to the present example.

[0142]

In summary, the present invention relates to a graphite heat conductor obtained by heat-treating a polymer film, which can effectively release and cool heat as compared with a conventional metal heat conductor.

Further, a heat conductor having a role of heat interruption and heat radiation can be obtained by utilizing the two-dimensional heat conduction and one-dimensional heat conduction characteristics.

Further, utilizing its light weight, it can be used as a heat radiator and a heat conductor for space and aircraft equipment.

[Brief description of the drawings]

FIG. 1 is a structural diagram of a graphite polymer composite thermal conductor of the present invention.

FIG. 2 is a configuration diagram of a composite of the same graphite film, polymer, and metal.

FIG. 3 is a view showing a graphite block thermal conductor having high thermal conductivity only in the same plane direction.

FIG. 4 is a view showing a block-shaped graphite heat conductor provided with high heat conductivity only in the same axial direction.

FIG. 5 is a view showing a block-shaped graphite thermal conductor having high thermal conductivity provided only in the same axial direction.

FIG. 6 is a view showing a graphite film in which the same side is cut into strips.

FIG. 7 is a configuration diagram in which strip-shaped portions of the graphite film of FIG. 6 are bundled together;

8 is a configuration diagram in which a flexible heat insulating material is wound around the bundled portion in FIG. 7;

9 is a perspective view in which the graphite film of FIG. 8 is installed under a heating element such as an electronic device.

FIG. 10 is a configuration diagram in which the graphite film of FIG. 9 is installed in a cold plate.

FIG. 11 is a plan view showing a conventional cold plate.

FIG. 12 is a sectional view of the cold plate taken along line XX of FIG. 11;

FIG. 13 is a plan view showing a conventional cold plate.

14 is a cross-sectional view of the cold plate of FIG. 13 taken along line YY.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Graphite film 2 Polymer layer 3 Metal layer 4 Heat insulating material 5 Heat receiving body 6 Refrigerant inflow pipe 7 Refrigerant outflow pipe 8 Heating element 9 Fin 10 Metal rod

Continuation of the front page (72) Inventor Jun Ehara 1006 Kadoma, Kazuma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (56) References JP-A-1-105199 (JP, A) JP-A-4-149012 (JP) JP-A-4-149014 (JP, A) JP-A-64-71156 (JP, A) JP-A-5-222620 (JP, A) JP-B-3-51302 (JP, B2) (58) Field surveyed (Int. Cl. ⁷ , DB name) C04B 35/52 C04B 41/89, 41/90

Claims (7)

(57) [Claims] 1. A graphite film obtained by heat-treating a predetermined polymer film and having a thermal conductivity of 500 W / m · K or more.
Cut into the strip to make a strip,
Graphite thermal conductor that bundles a part . 2. A heat treatment of a predetermined polymer film.
The obtained graphite film having a thermal conductivity of 500 W / m · K or more, an epoxy resin, a polyimide,
Midimide, polyamide, phenolic resin, polycarbonate
Nate, polyester, polybenzimidazole, AB
A graphite heat conductor having a laminated structure with a polymer layer containing S, polystyrene or polyethylene . 3. Heat treatment of a predetermined polymer film
The obtained graphite film having a thermal conductivity of 500 W / m · K or more, and the surface of the graphite film
In addition, graphite with a metal layer formed as a reflective film
Thermal conductor . 4. A method in which a plurality of predetermined polymer films are laminated after carbonizing a predetermined polymer film, or a plurality of predetermined polymer films are carbonized and then graphitized under mechanical pressure. A graphite block whose graphite surfaces are oriented parallel to each other, and which has a thermal conductivity in the direction of the graphite surface in a direction perpendicular to the graphite surface of 5 mm or less.
High thermal conductivity in thickness direction by cutting at lower thickness
Graphite heat conductor having. 5. A graphite block obtained by orienting a predetermined polymer film cut into strips or fibers in one direction and then carbonizing and graphitizing under mechanical pressure, of the alignment of graphite blocks having thermal conductivity in the direction of the alignment
To cut with a thickness of 5mm or less on a plane perpendicular to the direction
A graphite thermal conductor having higher thermal conductivity in the thickness direction . 6. A graphite block obtained by subjecting a predetermined polymer film wound substantially concentrically to carbonization and graphitization under mechanical pressure, wherein the graphite block has thermal conductivity in the axial direction of the concentric circles. 5m in a plane perpendicular to the axial direction of the concentric circle
High heat transfer in the thickness direction by cutting at thickness less than m
Conductive graphite heat conductor. 7. The polymer film according to claim 1, wherein the predetermined polymer film is at least one selected from the group consisting of polyoxadiazole, aromatic polyimide, aromatic polyamide, and polyparaphenylenevinylene having a thickness of 400 microns or less. Wherein said polymer film is at least 2400
2. A material obtained by heat treatment at a temperature of not less than ℃.
7. The graphite heat conductor according to any one of items 1 to 6.