Patent ID: 9249025
Filing Date: 2016-02-02
CPC Classification: C01B

Claim Text:
1. A method for producing a carbonaceous film, comprising the steps of: (1) winding a polymer film into a roll shape to obtain a roll-shaped polymer film at a temperature lower than a pyrolysis onset temperature of the polymer film, so that (1-1) a value determined for the whole roll-shaped polymer film 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) satisfies a relationship of Ts/Tf<0.33 or Ts/Tf>1.50 in a cross-section of the roll-shaped polymer film and (1-2) so that i) the cross-section of the roll-shaped polymer film has an inner portion defined by a first 50% of a total length of the polymer film and an outer portion defined by a second 50% of the total length of the polymer film, ii) the inner portion of the cross-section of the roll-shaped polymer film has a cross-section of the polymer film and optionally a cross-section of a space, and iii) a total cross-sectional area of the space counts for 0% or more and less than 25% of a total area of the inner portion of the cross-section of the roll-shaped polymer film; (2) adjusting a shape of the roll-shaped polymer film at a temperature equal to or higher than a pyrolysis onset temperature of the polymer film but equal to or lower than a temperature at which a weight of the polymer film is reduced by 40% as compared to that before start of heat treatment, so that 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 a thickness of the gap between adjacent layers of the polymer film (Ts) by a thickness of the polymer film (Tf) (Ts/Tf) satisfies a relationship of 0.33≦Ts/Tf≦1.50 in the cross-section of the roll-shaped polymer film and/or (2-2) so that i) the cross-section of the roll-shaped polymer film has an inner portion defined b a first 50% of a total length of the polymer film and an outer portion defined by a second 50% of the total length of the polymer film, ii) the inner portion of the cross-section of the roll-shaped polymer film has a cross-section of the polymer film and a cross-section of a space, and iii) a total cross-sectional area of the space counts for 25% or more of a total area of the inner portion of the cross-section of the roll-shaped polymer film; and then (3) heat-treating the roll-shaped polymer film so as to produce a carbonaceous film, wherein the polymer film is a polyimide film.