Kaneka Corporation

Makoto Mishiro

Takashi Inada

Yasushi Nishikawa

Yusuke Ohta

When a raw material graphite film bad in flatness is laminated onto another material, creases and other defects may be caused. In particular, when a graphite film having a large area is laminated, defects such as creases may be often caused. In order to solve such defects, a flatness correction treatment step is performed wherein a raw material graphite film is subjected to heat treatment up to 2000&#xb0; C. or higher while a pressure is applied thereto. This flatness correction treatment gives a graphite film good in flatness. Furthermore, when the flatness of the raw material graphite film is corrected by use of a thermal expansion of a core, a graphite film small in sagging can be obtained.

Method for improving the flatness of graphite film, graphite film, and method for producing same

Provided is a long and large-area graphite film having improved thermal diffusivity and flex resistance, and accompanied by ameliorated ruffling. According to a method for producing a graphite film, in which graphitization of a heat-treated film consisting of a carbonized polymer film is carried out in a state being wrapped around an internal core, the method being characterized in that a heat treatment is executed by controlling distance(s) between the internal core and the film, and/or between the layers of the film, a graphite film accompanied by significantly ameliorated ruffling can be obtained.

Method for producing graphite film

Graphite film

A graphite film showing an extremely low average tearing force is more likely to suffer from various kinds of defects, such as splitting, winding deviation, wrinkling, and poor dimensional accuracy, in a step of producing the graphite film and in a step of processing the graphite film. However, these defects can be prevented by using a graphite film that satisfies the following requirements: 1) having an average tearing force of not more than 0.08 N as determined by Trouser tear method in accordance with JIS K7128; and 2) having sag of not less than 5 mm and not greater than 80 mm as determined by a method of film windability evaluation in accordance with JIS C2151.

Method for producing graphite film, method for rewinding same, and method for producing graphite composite film and graphite die-cutting product

A graphite film which is low in graphite dust generation can be produced by properly selecting acid dianhydride and diamine which constitute a polyimide film, which polyimide film is a raw material of the graphite film. Specifically, the graphite film which is low in graphite dust generation can be obtained if (1) the acid dianhydride is PMDA and the diamine has a molar ratio of ODA/PDA in a range of 100:0 to 80:20, or (2) the acid dianhydride has a molar ratio of PMDA/BPDA in a range of 80:20 to 50:50, and the diamine has a molar ratio of ODA/PDA in a range of 30:70 to 90:10.

Graphite film and process for producing graphite film

In a method for producing a carbonaceous film in which a polymer film is wrapped around a core and is subjected to a heat treatment, material film surfaces during the carbonization step are prevented from fusion, whereby a long carbonaceous having a large area film is obtained. Fusion can be prevented by subjecting a polymer film to a heat treatment under a reduced pressure, and under a reduced pressure while allowing an inert gas to flow. The range of the pressure reduction is preferably &#x2212;0.08 MPa to &#x2212;0.01 kPa. It is preferred to carry out carbonization with the pressure reduced in the range of from &#x2212;0.08 MPa to &#x2212;0.01 kPa while allowing an inert gas to flow. In addition, the polymer film wrapped around the core is placed in an outer casing, and provided that a value derived by dividing (internal diameter of the outer casing&#x2212;diameter of the core) by 2 is designated as 'a' (mm), and a thickness of wrapping of the polymer film is designated as 'b' (mm), a value (b/a) derived by dividing the &#x201c;b&#x201d; by the &#x201c;a&#x201d; is set to fall within the range of from 0.2 to 0.9.

Method for manufacturing carbonaceous film and graphite film obtained thereby

Graphite film and method for producing graphite film

Disclosed herein is a method for producing a roll-shaped carbonaceous film by polymer pyrolyzis while suppressing the occurrence of fusion bonding in the roll-shaped carbonaceous film. The carbonaceous film production method includes the step of heat-treating a polymer film wound into a roll, wherein, at a temperature equal to or higher than the pyrolyzis onset temperature of the polymer film but equal to or lower than a temperature at which the weight of the polymer film is reduced by 40% as compared to that before heat treatment, the roll-shaped polymer film has (2-1) a gap between layers of the polymer film so that a value determined for the whole roll-shaped polymer film by dividing the thickness of the gap between adjacent layers of the polymer film (Ts) by the thickness of the polymer film (Tf) (Ts/Tf) satisfies a relationship of 0.33&#x2266;Ts/Tf&#x2266;1.50 and/or (2-2) a space inside a 50% cross-sectional circle of the roll-shaped polymer film so that the area of the space inside the 50% cross-sectional circle is 25% or more of the cross-sectional area of the 50% cross-sectional circle.

Method for producing carbonaceous film and method for producing graphite film

The present invention performs special heat treatment on a polymer film in a temperature range from (i) a lower limit to temperature rise being equal to or higher than a starting temperature of thermal decomposition of the polymer film, i.e., which is a temperature observed at an early stage of the thermal decomposition of the polymer film, to (ii) an upper limit to temperature rise being equal to or lower than an intermediate temperature of thermal decomposition of the polymer film. This reduces foaming in the film during graphitization treatment following the special heat treatment. Thus, even with a higher heating rate for graphitization, it is possible to produce a graphite film having good quality.

Process for producing graphite film

Disclosed herein is a method for producing an elongated (rolled) carbonaceous film by polymer pyrolysis while suppressing the fusion bonding of the carbonaceous film. The method for producing a carbonaceous film includes the step of heat-treating a polymer film wound into a roll, wherein the heat treatment is performed after the polymer film is wound into a roll to have a gap between adjacent layers of the polymer film at a temperature lower than a pyrolysis onset temperature of the polymer film so that the roll of polymer film as a whole satisfies a relationship that a value obtained by dividing a thickness of a gap between adjacent layers of the polymer film (Ts) by a thickness of the polymer film (Tf) (Ts/Tf) is 0.16 or higher but 1.50 or lower. As a method for forming gaps between the layers of the polymer film, a method in which the polymer film is wound into a roll together with a slip sheet and then the slip sheet is removed can be used, which is effective at suppressing the fusion bonding of a carbonaceous film.

Method for producing carbonaceous film, method for producing graphite film, roll of polymer film, and roll of carbonaceous film

A graphite film with fewer wrinkles and/or undulations is obtained providing two or more stages of heating space and carrying out continuous baking. Especially when a cooling space is provided between each of the heating spaces and another, a graphite film can be obtained which is excellent in flatness and has a high thermal diffusivity.

Method for producing graphite film and method for producing carbonized film

Disclosed herein is a method for producing an elongated (rolled) carbonaceous film by polymer pyrolysis while suppressing the fusion bonding and the rippling of the carbonaceous film. The method for producing a carbonaceous film includes the step of heat-treating a polymer film wound into a roll, wherein the heat treatment is performed after the polymer film is wound into a roll at a temperature lower than a pyrolysis onset temperature of the polymer film so that the roll of polymer film has a center and has a space inside its cross-sectional circle (50% cross-sectional circle) (space within 50% cross-sectional circle) whose center is at the center and whose circumference passes through a point at which a length of the polymer film from an inner end thereof is 50% of a total length of the polymer film and that an area of the space within 50% cross-sectional circle is 25% or more of an area of the 50% cross-sectional circle. Particularly, providing a space between a core and an innermost layer of the roll of polymer film is more effective at solving the above problem.

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Settsu, Japan

Makoto Mishiro