Thermally conductive body and method of manufacturing the same

1. A thermally conductive body for placement between a heat generating body and a heat radiating body, the thermally conductive body being molded formed from a thermally conductive polymer composition; the thermally conductive polymer composition comprising:

a polymer matrix; and

a thermally conductive filler, in which at least part of the thermally conductive filler is formed in the shape of fibers, and oriented in a certain direction,

wherein an outer surface of the thermally conductive body intersects said direction and contacts at least one of the heat generating body and the heat radiating body at the time of use,

wherein the thermally conductive filler formed in the shape of fibers includes:

ends that are exposed on the outer surface and have protrusions extending along the outer surface, said protrusions having a cross-section perpendicular to a fiber axial direction which is larger than the cross-section of the fiber that is within the polymer matrix.

2. The thermally conductive body according to claim 1 wherein the thermally conductive filler formed in the shape of fibers comprises carbon fibers.

3. The thermally conductive body according to claim 1 ,

wherein the thermally conductive filler formed in the shape of fibers includes:

a rod-like portion;

a fiber axial direction; and

a cross section perpendicular to the fiber axial direction in the rod-like portion, and

wherein the end having a protrusion of the thermally conductive filler formed in the shape of fibers includes:

a cross section which is perpendicular to the fiber axial direction of the thermally conductive filler formed in the shape of fibers and larger than a cross section which is perpendicular to the fiber axial direction of the thermally conductive filler formed in the shape of fibers at the rod-like portion.

4. The thermally conductive body according to claim 1 , wherein the polymer matrix is a polymer material of a silicone type or an acrylic type.

5. The thermally conductive body according to claim 1 , wherein the polymer matrix has a viscosity of 1000 mPa·s or less at 25° C.

6. The thermally conductive body according to claim 1 , wherein the content of the thermally conductive filler in the above thermally conductive polymer composition is 90 mass% or less.

7. The thermally conductive body according to claim 1 , wherein the proportion of the thermally conductive filler formed in the shape of fibers in the total amount of the thermally conductive filler is 7 mass% or more and less than 35 mass%.

8. The thermally conductive body according to claim 1 , wherein the proportion of the thermally conductive filler formed in the shape of fibers exposed on and intersecting the outer surface is 50 to 100%.

9. The thermally conductive body according to claim 1 , wherein the thermally conductive filler formed in the shape of fibers has a distal end, and the distance between the outer surface and the distal end of the fibrous filler which is exposed on and intersecting the outer surface of the body is not more than 50 μm.

10. A method for manufacturing a thermally conductive body which is for placement between a heat generating body and a heat radiating body, the thermally conductive body being molded formed from a thermally conductive polymer composition; the thermally conductive polymer composition including:

a polymer matrix; and

a thermally conductive filler, in which at least part of the thermally conductive filler is formed in the shape of fibers, and oriented in a certain direction,

wherein an outer surface of the thermally conductive body intersects said direction and contacts at least one of the heat generating body and the heat radiating body at the time of use,

wherein the thermally conductive filler formed in the shape of fibers includes:

ends that are exposed on the outer surface and have protrusions extending along the outer surface,

the method comprising:

preparing the thermally conductive polymer composition;

orienting the thermally conductive filler formed in the shape of fibers in a certain direction;

molding the thermally conductive body from the thermally conductive polymer composition while maintaining the orientation of the above thermally conductive filler,

exposing ends of the oriented thermally conductive filler on the outer surface; and

forming a protrusion in the end of the thermally conductive filler.

11. The method according to claim 10 , wherein the step of orienting is performed by applying a magnetic field to the thermally conductive polymer composition, thereby orienting the thermally conductive filler formed in the shape of fibers.

12. The method according to claim 11 , wherein the step of orienting is performed by further applying vibration to the above thermally conductive polymer composition, thereby orienting the thermally conductive filler formed in the shape of fibers.

13. The method according to claim 12 , wherein the thermally conductive polymer composition has a natural frequency, and the vibration applied to the thermally conductive polymer composition has a frequency lower than the natural frequency of the thermally conductive polymer composition.

14. The method according to claim 13 , wherein the frequency of the vibration applied to the thermally conductive polymer composition is 0.1 to 100 Hz.

15. The method according to claim 14 , wherein the frequency of the vibration applied to the thermally conductive polymer composition is 1 to 100 Hz.

16. The method according to claim 12 , wherein the vibration applied to the thermally conductive polymer composition has an amplitude of 0.1 to 20 mm.

17. The method according to claim 16 , wherein the vibration applied to the thermally conductive polymer composition has an amplitude of 1 to 20 mm.