JP2001250894A - Heat conductive material and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat conductive material which has good heat conductiv ity and is easily manufactured. SOLUTION: A gel substance 1 of heat conductivity is mixed with a carbon fiber 3 for dispersion, which is molded into a plate by extrusion. Thus, the carbon fiber 3 is oriented in extrusion direction. The plate is wound with the extrusion direction as an axis, which is enclosed with an elastic body 5 to provide a mold body 7. The mold body 7 is sliced along a plane vertical to the axis of winding as indicated with a broken line, providing a plate-like heat conductive material 7a. The heat conductive material 7a thus manufactured, has the carbon fiber 3 oriented in thickness direction, resulting in excellent heat conductivity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat conductive material arranged to be used in contact with a heating element for promoting heat radiation from a heating element such as an electronic component, and a method of manufacturing the same. More specifically, the present invention relates to a heat conductive material using carbon fibers and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a rubber such as silicone rubber or EPDM is filled with a heat conductive filler such as alumina and kneaded.
Heat conductive materials formed by molding have been considered. This kind of heat conductive material is interposed, for example, between an electronic component serving as a heat source and a component serving as a heat sink (hereinafter simply referred to as a heat sink) such as a heat sink or a housing panel inside the electric / electronic device. Used to be arranged to let. When the heat conductive material is disposed in this manner, heat generated by the electronic components and the like can be satisfactorily released to the heat sink. For this reason, this type of heat conductive material has attracted attention as an indispensable material for, for example, increasing the speed of a CPU.

[0003]

However, with this kind of heat conductive material, a heat conductivity of only about 1 to 5 W / m · K can be obtained. On the other hand, in recent years, the operating frequency of CPUs and the like has increased, and the amount of heat generated has also increased. Therefore, there is a demand for a heat conductive material that efficiently radiates heat from the CPU and the like. On the other hand, carbon fiber has a length of 200 W / m
It is known to have a very high thermal conductivity, of the order of K. However, when carbon fibers are dispersed in a base material formed in a plate shape by silicone rubber or the like, it is extremely difficult to orient and disperse each carbon fiber in the thickness direction, and the production cost of the heat conductive material is reduced. Get higher. Further, when carbon fibers are randomly oriented in the base material, the production is relatively easy, but in this case, the high thermal conductivity as described above is not obtained.

Accordingly, an object of the present invention is to provide a heat conductive material which is easy to manufacture and has good heat conductivity.

[0005]

Means for Solving the Problems and Effects of the Invention The present invention according to claim 1 which has been made to achieve the above object, comprises a base material formed of a gel-like substance in a plate shape and a base material dispersed in the base material. The invention further provides a heat conductive material including carbon fibers oriented in the thickness direction of the base material and a holding member for holding the shape of the base material.

In the present invention thus constituted, since the base material is made of a gel-like substance, the carbon fibers dispersed in the base material can be relatively easily oriented in a certain direction. For example, when a gel material in which carbon fibers are dispersed is extruded or injection-molded, the carbon fibers can be easily oriented in the extrusion direction or the injection direction. When the gel material is press-formed, the carbon fibers can be oriented in a direction parallel to the press surface.

[0007] In the present invention, since the plate-like substrate is constituted by such a gel-like substance, the carbon fibers dispersed in the substrate can be relatively easily oriented in the thickness direction. . And the heat conductive material of the present invention exhibits extremely good heat conductivity by the carbon fibers being oriented in the thickness direction. However, when the base material is composed of a gel-like substance, it is difficult to maintain its shape stably. Therefore, in the present invention, the shape of the base material is held by a holding member provided separately from the base material. For this reason, it is possible to stably maintain the shape of the base material and stably maintain the good thermal conductivity. Thus, the heat conductive material of the present invention is easy to manufacture and has good heat conductivity. In the present invention, the carbon fibers in the base material do not need to be 100% oriented in the above-mentioned fixed direction, and may have some variation in the orientation direction.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the holding member is an elastic body that surrounds the base material from the periphery. In the present invention, since the holding member is constituted by the elastic body surrounding the base material from the periphery, it is possible to favorably prevent the base material from spreading in the width direction (area direction). Further, since this type of heat conductive material is used with one surface in contact with a heat source such as an electronic component and the other surface in contact with a heat sink, deformation in the thickness direction can be prevented by those members. Therefore, in the present invention, in addition to the effect of the first aspect of the present invention, there is an effect that the deformation of the base material is more favorably suppressed, and the thermal conductivity can be more favorably maintained.

The invention described in claim 3 is the first or second invention.
In addition to the configuration described above, the holding member is a plate-like member adhered to one surface of the base material. In the present invention, since the holding member is formed by the plate-like member attached to one surface of the base material, one end of the carbon fiber is fixed to the plate-like member, and the interval between the carbon fibers changes. It becomes difficult to do. For this reason, for example, even when used for a long period of time, the dispersion state of the carbon fibers does not shift. Therefore, according to the present invention, in addition to the effects of the first or second aspect of the present invention, there is an effect that the dispersion state of the carbon fibers can be more favorably maintained, and the thermal conductivity can be more favorably maintained.

According to a fourth aspect of the present invention, in addition to the configuration of any one of the first to third aspects, the base material has a structure in which a single band-shaped base material is wound in a plane. Features. The substrate having such a configuration can be easily manufactured as follows. For example, a gel-like substance in which carbon fibers are dispersed is formed into a plate by extrusion, injection molding, or press molding, and the obtained gel-like substance is wound around the carbon fiber orientation direction as an axis. The molded body thus obtained may be cut along a plane perpendicular to the axis of the winding. By doing so, the substrate can be formed in a plate shape, and the carbon fibers can be oriented very favorably in the thickness direction of the substrate, and the production is easy. Therefore, in the present invention, in addition to the effect of the invention described in any one of the first to third aspects, the effect that the production is further facilitated and the better heat conductivity is obtained.

According to a fifth aspect of the present invention, in addition to the configuration of any one of the first to third aspects, the base material has a structure in which a plurality of strip-shaped base materials are arranged in parallel. . The substrate having such a configuration can be easily manufactured as follows. For example, a gel-like substance in which carbon fibers are dispersed is formed into a plate shape by extrusion, injection molding, or press molding, and the obtained gel-like substance plate is subjected to a plurality of plates along the carbon fiber orientation direction. Then, a plurality of plates after the cutting are stacked in the same orientation direction, and the molded body thus obtained may be cut along a plane perpendicular to the orientation direction. By doing so, the substrate can be formed in a plate shape, and the carbon fibers can be oriented very favorably in the thickness direction of the substrate, and the production is easy.
Therefore, in the present invention, in addition to the effect of the invention described in any one of the first to third aspects, the effect that the production is further facilitated and the better heat conductivity is obtained.

According to a sixth aspect of the present invention, in addition to the constitution of any one of the first to fifth aspects, the gel-like substance constituting the base has thermal conductivity. In the present invention, not only the carbon fibers but also the gel material constituting the base material has thermal conductivity, so that the thermal conductivity of the entire thermal conductive material is further improved. Therefore, in the present invention, claims 1 to
In addition to the effect of the invention described in any one of 5 above, there is an effect of having better thermal conductivity.

According to a seventh aspect of the present invention, in addition to any one of the first to sixth aspects, the carbon fibers are dispersed and held in the base material so that the orientation direction can be changed. And That is, in the present invention, the carbon fibers are dispersed and held in the base material so that the orientation direction can be changed by moving in the base material or displacing integrally with the base material. Therefore, the flexibility of the heat conductive material as a whole is improved, and the adhesiveness with electronic components such as a CPU and a heat sink is improved. Therefore, in the present invention, in addition to the effect of the invention described in any one of the first to sixth aspects, there is an effect that the heat generated by the electronic component or the like can be more efficiently released to the heat sink side. Since the carbon fiber has extremely good thermal conductivity as described above, even if the carbon fiber is inclined and the thermal conductivity becomes a value obtained by multiplying the cosine of the inclination angle, sufficient thermal conductivity is obtained. Property is obtained.

[0014] The invention according to claim 8 is a first step in which a gel-like substance in which carbon fibers are dispersed is formed into a plate by extrusion, injection molding or press molding, and the above-mentioned step formed in the first step is performed. A second step of winding the plate of the gel-like substance around the orientation direction of the carbon fibers, a third step of surrounding the molded body obtained in the second step with an elastic body from the periphery, A fourth step of cutting the formed body obtained in the third step along a plane perpendicular to the axis of the winding to form a plate-shaped heat conductive material. The gist of the method is that of

In the first step of the present invention, a gel-like substance in which carbon fibers are dispersed is formed into a plate by extrusion, injection molding, or press molding. For this reason, in the plate formed by this step, the carbon fibers are contained in a gel material in a certain direction (the direction of extrusion in the case of extrusion, the direction of injection in the case of injection molding, and the direction parallel to the press surface in the case of press molding) ). In the subsequent second step, the gel-like substance plate formed in the first step is wound around the orientation direction of the carbon fibers as an axis. As described above, if the molded body thus obtained is cut along a plane perpendicular to the axis of the winding, the substrate according to claim 4 is obtained. Therefore, in the following third step, the molded body obtained in the second step is surrounded by an elastic body from the periphery, and in the subsequent fourth step, the molded body obtained in the third step is attached to the axis of the winding. Cut along a vertical plane.

Therefore, according to the present invention, the heat conductive material according to the fourth and second aspects can be easily manufactured. Moreover, in the present invention, the cutting in the fourth step is performed after the molded body obtained in the second step is surrounded by the elastic body (third step), so that the cutting can be performed very easily. Therefore, according to the manufacturing method of the present invention, the heat conductive material according to claims 4 and 2 can be manufactured very easily.

According to a ninth aspect of the present invention, there is provided a first step in which a gel-like substance in which carbon fibers are dispersed is formed into a plate by extrusion molding, injection molding, or press molding; A second step of cutting the gel-like substance plate into a plurality of plates along the orientation direction of the carbon fiber and stacking the plurality of cut plates in the same orientation direction; and A third step of surrounding the formed body with an elastic body from the periphery, and cutting the formed body obtained in the third step along a plane perpendicular to the orientation direction to obtain a plate-like heat conductive material. And a fourth step of producing the heat conductive material.

In the first step of the present invention, similarly to the invention of claim 8, the gel-like substance in which carbon fibers are dispersed is formed into a plate by extrusion, injection molding or press molding. For this reason, in the plate formed by this step, the carbon fibers are oriented in a certain direction in the gel material as described above. In the subsequent second step, the plate of the gel-like substance formed in the first step is cut into a plurality of plates along the orientation direction of the carbon fibers, and the cut plurality of plates are aligned in the orientation direction. Laminate. As described above, if the thus obtained molded body is cut along a plane perpendicular to the orientation direction, the substrate according to claim 5 is obtained. So, the third
In the step, the molded body obtained in the second step is surrounded by an elastic body from the periphery, and in the subsequent fourth step, the molded body obtained in the third step is cut along a plane perpendicular to the orientation direction. are doing.

Therefore, according to the present invention, the heat conductive material according to the fifth and second aspects can be easily manufactured. Moreover, in the present invention, the cutting in the fourth step is performed after the molded body obtained in the second step is surrounded by the elastic body (third step), so that the cutting can be performed very easily. Therefore, according to the manufacturing method of the present invention, the heat conductive material according to claims 5 and 2 can be manufactured very easily.

According to the present invention, the cross-sectional shape (aspect ratio, etc.) of the molded article obtained in the second step can be set more freely than in the invention described in claim 8, so that the molded product can be manufactured more easily. The planar shape of the heat conductive material can be set more freely. However, in the invention according to claim 8, it is not necessary to cut and laminate the gel-like substance plate formed in the first step, and the heat conductive material can be manufactured more easily.

[0021]

Next, an embodiment of the present invention will be described with reference to the drawings. 1 and 2 are perspective views showing a manufacturing method according to the first embodiment of the present invention. In the present embodiment, a gel material 1 having thermal conductivity (for example, a silicone gel filled with a thermal conductive filler or the like) and a carbon fiber 3 (for example, a PAN or PICTH-based long fiber shortened or a gas phase method) are used. , Etc.), were mixed and dispersed, and formed into a plate shape as shown in FIG. 1 (A) by extrusion molding. Then, as shown in FIG. 1A, the carbon fibers 3 were not completely 100%, but could be favorably and easily oriented in the extrusion direction (first step).

Subsequently, the plate of the gel-like substance 1 thus obtained is wound around the extrusion direction (ie, the orientation direction of the carbon fiber 3) as an axis as shown in FIG. 2) Inserting the thus obtained molded body into an elastic body 5 (for example, made of silicone rubber, urethane rubber, styrene rubber, etc.) having a square cross section as shown in FIG. Thus, the elastic body 5 was surrounded from the periphery (third step). The molded body 7 thus obtained is obtained by surrounding the gel-like substance 1 with the elastic body 5,
The shape can be stably maintained.

Then, as shown by a broken line in FIG. 2, the molded body 7 is thinly cut along a plane perpendicular to the axis of the winding to obtain a plate-shaped heat conductive material 7a. (Fourth step). Thermal conductive material 7 manufactured in this manner
Since the carbon fiber 3 is oriented in a thickness direction (a direction sandwiched between a heat source such as an electronic component and a heat sink), a exhibits extremely good thermal conductivity. Moreover, since the gel material 1 itself has thermal conductivity in the heat conductive material 7a, the heat conductive material 7a as a whole exhibits better thermal conductivity. In addition, since the periphery is surrounded by the elastic body 5, the gel material 1 as a base material can be prevented from spreading in the width direction (area direction) and its deformation can be suppressed well, and the above-described good heat can be obtained. Conductivity can be stably maintained.

Although the gel material 1 is exposed on both sides of the heat conductive material 7a, the heat conductive material 7a is used with one surface in contact with a heat source such as an electronic component and the other surface in contact with a heat sink. For this reason, deformation of the heat conductive material 7a in the thickness direction can be prevented by members such as the electronic components and the heat sink. Further, since the gel-like substance 1 is exposed on both sides and directly abuts on the above member together with the carbon fiber 3, the heat conductive material 7a
Have better thermal conductivity. Further, since the heat conductive material 7a can be manufactured by the above-described extremely simple process, the manufacturing cost can be reduced favorably.

Next, FIG. 3 is a perspective view showing a manufacturing method according to a second embodiment of the present invention. In the present embodiment, FIG.
As shown in (A), a plate of the gel-like substance 1 formed in the same manner as in the above embodiment is cut into a plurality of plates along the orientation direction of the carbon fibers 3, and the cut plate is aligned in the orientation direction. And laminated (second step). Then, the molded body obtained as described above is surrounded from the periphery by the above-mentioned elastic body 5, and the molded body 1 shown in FIG.
7 (third step), and the molded body 17 was cut along a plane perpendicular to the above-mentioned orientation direction as shown by a broken line in FIG. 3 to obtain a plate-like heat conductive material 17a. Also in this case, the heat conductive material 17a having extremely good heat conductivity could be manufactured very easily (ie, at low cost).

In the present embodiment, since the plate of the gel-like substance 1 is cut along the above-mentioned orientation and laminated.
The planar shape (aspect ratio, etc.) of the heat conductive material 17a can be set more freely than in the first embodiment. However, in the first embodiment, it is not necessary to cut and stack the plates of the gel-like substance 1, and the heat conductive material 7a can be manufactured more easily than in the present embodiment. In any of the embodiments, the plane shape of the heat conductive members 7a and 17a is not limited to a square, but can be formed into various shapes such as a circle and a triangle, and the degree of freedom differs between the above embodiments. Occurs.

Although the present invention has been described with reference to the specific embodiments, the present invention is not limited to the above-described embodiments, but may be implemented in various other forms without departing from the scope of the present invention. Can be implemented. For example, gel substance 1
May be an adhesive or the like. The plate of the gel substance 1 shown in FIG. 1A may be formed by injection molding or press molding. However, in the case of extrusion or injection molding, the carbon fibers 3 are oriented in the extrusion or injection direction, whereas in the case of press molding, the carbon fibers 3 are oriented in a direction having a two-dimensional variation parallel to the press surface. The fibers 3 can be oriented. For this reason, it is better to manufacture a plate of the gel material 1 by extrusion molding or injection molding.
The carbon fibers 3 can be more preferably oriented in the thickness direction, and the heat conductivity of the heat conductive material can be further improved.

Further, the gel-like substance 1 does not necessarily need to be formed into a plate-like shape once, and if the directions of the carbon fibers 3 can be aligned during extrusion or injection by devising the shape of the mandrel or die, It may be directly shaped into a prism. Further, the heat conductive material 7 according to each of the above embodiments is used.
In FIGS. 4A and 4A, as schematically shown in FIG. 4A, a plate-like gel-like substance 1 in which carbon fibers 3 are oriented and dispersed in the thickness direction is applied from the periphery by an elastic body 5 as a holding member. Although it is surrounded to prevent deformation, various forms of the holding member are conceivable.

For example, as schematically shown in FIG. 4 (B), a heat conductive plate member is provided on one surface of a plate gel material 1 in which carbon fibers 3 are oriented and dispersed in the thickness direction. 55 (for example, a silicone resin sheet filled with a heat conductive filler)
May be attached. Also in this case, the deformation of the gel material 1 can be favorably suppressed. Further, in this case, one end of the carbon fiber 3 is fixed to the plate-like member 55, and the distance between the carbon fibers 3 is hard to change. For this reason, for example, even in the case where the carbon fiber 3 is used obliquely for a long time, the dispersion state of the carbon fibers 3 does not become uneven, and the thermal conductivity can be maintained more favorably. Further, the holding member may be a combination of the embodiment of FIG. 4A and the embodiment of FIG. 4B. For example, the heat conducting materials 7a and 17a of the above-described embodiment are used.
A plate-like member 55 may be adhered to one side of.

Note that the heat conducting material 7a,
In 17a, the hardness of the gel-like substance 1 is adjusted so that the carbon fibers 3 can change the orientation direction.
It can be dispersed and held inside. That is, the carbon fibers 3 are dispersed and held so that the orientation direction thereof can be changed by moving in the gel-like substance 1 or displacing integrally with the gel-like substance 1.
In this case, the flexibility of the heat conductive members 7a and 17a as a whole is improved, and the adhesion to the electronic components and the heat sink is improved. Therefore, in this case, the heat generated by the electronic components and the like can be more favorably released to the heat sink side. Note that since the carbon fibers 3 have extremely good thermal conductivity as described above, even if the carbon fibers 3 are inclined and the thermal conductivity becomes a value obtained by multiplying the cosine of the inclination angle, the thermal conductivity becomes high. Conductive material 7a, 1
7a has sufficient thermal conductivity.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a manufacturing method according to a first embodiment.

FIG. 2 is a perspective view illustrating a continuation of the manufacturing method.

FIG. 3 is a perspective view illustrating a manufacturing method according to a second embodiment.

FIG. 4 is an explanatory view schematically showing various forms of a holding member.

[Explanation of symbols]

1: Gel-like substance 3: Carbon fiber
5 Elastic body 7, 17 Molded body 7a, 17a
... Heat conductive material 55 ... Plate member

Claims (9)

[Claims] 1. A base material composed of a gel-like substance in a plate shape, carbon fibers dispersed in the base material and oriented in the thickness direction of the base material, and holding the shape of the base material A heat conductive material, comprising: a member; 2. The heat conductive material according to claim 1, wherein said holding member is an elastic body surrounding said base material from the periphery. 3. The heat conductive material according to claim 1, wherein said holding member is a plate-like member adhered to one surface of said base material. 4. The heat conductive material according to claim 1, wherein the base material has a configuration in which a single band-shaped base material is wound in a planar shape. 5. The heat conductive material according to claim 1, wherein the base has a configuration in which a plurality of strip-shaped bases are arranged in parallel. 6. The heat conductive material according to claim 1, wherein the gel material constituting the base material has thermal conductivity. 7. The heat conductive material according to claim 1, wherein the carbon fibers are dispersed and held in the substrate so that the orientation direction can be changed. 8. A first step of extruding, gelling or press-molding a gel-like substance in which carbon fibers are dispersed, and forming the gel-like substance plate formed in the first step. ,
A second step of winding the carbon fiber around the orientation direction of the carbon fiber, a third step of surrounding the molded body obtained by the second step with an elastic body from the periphery, and a third step of: A fourth step of cutting the formed body along a plane perpendicular to the axis of the winding to form a plate-shaped heat conductive material. 9. A first step of extruding, gelling or press-molding a gel-like substance in which carbon fibers are dispersed, and forming the gel-like substance plate formed in the first step. ,
Cutting a plurality of plates along the orientation direction of the carbon fiber into a plurality of plates, and stacking the plurality of cut plates in the same orientation direction;
A step of surrounding the molded body obtained in the second step with an elastic body from the periphery, and cutting the molded body obtained in the third step along a plane perpendicular to the orientation direction. And a fourth step of forming a plate-shaped heat conductive material.