Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.