JP2016016998A - Method for producing carbon film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method capable of efficiently producing a carbon film having a large shape and obtaining a high purity carbon film.SOLUTION: There is provided a method for producing a carbon film which comprises: a step of forming projections 12 along the side in the longitudinal direction of a polymer film 11; a step of winding a polymer film 11 on a core material 13; and a step of arranging the polymer film 11 wound on the core material so that the central axis of a core material 12 is oriented in a vertical direction and followed by heat treatment, wherein the thickness of the projections 12 is set at one time or more and 4 times or less of the thickness of the polymer film.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing a carbon film used for a heat dissipation sheet or the like.

  In recent years, as the performance of various electronic devices has increased, the amount of heat generated by heat-generating components such as ICs has increased, and the housing has become hot, or the IC's operating speed has slowed due to excessively high IC temperatures. Come on. Therefore, the generated heat is diffused by using a sheet having excellent thermal conductivity in the surface direction, such as a graphite sheet. As this graphite sheet, a pyrolytic graphite sheet obtained by pyrolyzing a polymer sheet such as polyimide in a furnace is often used. In this case, a polymer sheet cut to a predetermined size is usually placed in a plurality of furnaces and heat treated.

  As prior art document information related to the invention of this application, for example, Patent Document 1 is known.

JP 2009-132602 A

  However, as the size of the required pyrolytic graphite sheet increases, if it is cut from a predetermined size and heat-treated, the end material becomes larger, resulting in poor production efficiency. Come. On the other hand, there is also a method of obtaining a carbon sheet by heat-treating a long polymer sheet wound around a core, but since the polymer sheet contracts when it thermally decomposes, cracks and breaks are likely to occur. There is a problem.

  In order to solve the above-mentioned problem, the present invention is a method for producing a carbon film through a heat treatment process in a state in which a polymer film is wound in a roll shape, and a protrusion along a longitudinal side of the polymer film A step of forming a polymer film, a step of winding a polymer film around the core material, and a step of arranging and heat-treating the polymer film wound around the core material so that the central axis of the core material is in the vertical direction The height of the part is 1 to 4 times the thickness of the polymer film.

  By performing as described above, the polymer film wound around the core material has a space formed by the protrusions, so that it is difficult for force to be applied to the polymer film even when contracted. Since the central axis of the core material is oriented in the vertical direction, the gas generated by the thermal decomposition can easily escape from between the polymer films, and a carbon film with few impurities can be obtained. By heat-treating this at a higher temperature, a pyrolytic graphite sheet having a high thermal conductivity can be obtained efficiently.

The figure which shows the manufacturing method of the carbon film in one embodiment of this invention The principal part top view of the polyimide film which provided the projection part in one embodiment of this invention Sectional drawing of the principal part of the polyimide film which provided the projection part in one embodiment of this invention

  Hereinafter, the manufacturing method of the carbon film in one embodiment of the present invention is explained, referring to drawings.

  FIG. 1 is a diagram showing a method for producing a carbon film in one embodiment of the present invention. First, a polyimide film 11 having a width of about 300 mm, a length of about 500 m, and a thickness of about 38 micrometers is prepared as a polymer film. Next, the protrusion 12 is formed along the longitudinal side of the polyimide film 11. For example, as shown in FIG. 1A, the protrusion 12 can be formed by passing both ends of the polyimide film 11 between rollers having a predetermined shape. . Thereafter, the polyimide film 11 on which the protrusions 12 are formed is wound around a graphite core material 13. In this case, the formation of the protrusion and the winding onto the core material may be performed separately, but may be performed continuously as shown in FIG.

  Next, as shown in FIG. 1 (b), the core material 13 wound with the polyimide film 11 is placed in the furnace 14 so that the central axis thereof is oriented in the vertical direction, and fired at about 1300 ° C. in a nitrogen atmosphere. To obtain a carbon film. A pyrolytic graphite sheet can be obtained by further firing the carbon film at about 2600 ° C. in an argon atmosphere.

  As shown in FIG. 2, the protrusions 12 are continuously formed in a region about 10 mm inward from both ends of the polyimide film 11 so that the minimum distance (D) between the centers is about 3.5 mm. The height of the protrusion 12 is about 80 micrometers. Here, the height of the protrusion 12 is H in FIG.

  When the polyimide film 11 having such a protrusion 12 is wound around the core material 13, a space is formed around the protrusion 12. Therefore, even if the polyimide film 11 contracts during thermal decomposition, the force can be relaxed by the space, and the occurrence of cracks and breaks can be suppressed. Furthermore, since the central axis of the core material 13 is oriented in the vertical direction, the gas generated by the thermal decomposition can easily escape from between the polyimide films 11, and a carbon film with few impurities can be obtained.

  Here, it is desirable that the height of the protruding portion 12 be 1 to 4 times the thickness of the polyimide film 11. If the height of the protrusion 12 is less than 1 times the thickness of the polyimide film 11, the polyimide film shrinks easily during thermal decomposition, and cracks and breaks are likely to occur. When the film 11 is wound around the core material 13, the diameter becomes too large and the production efficiency is deteriorated. If it is 4 times or less, even if the projection 12 is present in the state of the polyimide film 11, when the carbon is carbonized and further graphitized, the projection becomes inconspicuous and does not affect the thermal conductivity. Therefore, it is desirable that the height of the protrusion 12 is 1 to 4 times the thickness of the polyimide film 11.

  Further, the protrusions 12 are preferably arranged in a grid pattern as shown in FIG. 2, and the direction in which the distance between the centers is the shortest is oblique to the width direction of the polyimide film 11. By doing in this way, the gas which generate | occur | produces when the polyimide film 11 thermally decomposes becomes easy to escape | omit, and a carbon film with few impurities can be obtained.

  Furthermore, it is desirable to wind the polyimide film 11 around the core material 13 in the direction in which the protruding portion 12 protrudes toward the core material 13. Since the shrinkage force at the time of thermal decomposition is greater near the core material 13, cracks and breaks are likely to occur near the core material 13. By projecting the projecting portion 12 toward the core material 13, the projecting portion 12 comes into contact with the core material 13, and it is possible to prevent cracks and breakage at a portion close to the core material 13.

  The carbon film manufacturing method according to the present invention can produce a carbon film having a large shape efficiently and can obtain a carbon film with high purity, which is industrially useful.

11 Polyimide film 12 Protrusion 13 Core material 14 Furnace

Claims (2)

A method for producing a carbon film through a step of heat-treating a polymer film in a roll shape,
Forming a protrusion along a longitudinal side of the polymer film;
Winding the polymer film around a core material;
Arranging and heat-treating a polymer film wound around the core so that the central axis of the core is oriented in the vertical direction,
The method for producing a carbon film, wherein the height of the protrusion is 1 to 4 times the thickness of the polymer film. The method of manufacturing a carbon film according to claim 1, wherein the protruding portion protrudes toward the core member.

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