| abstract |
In the preparation of a film by melt-extrusion process of thermoplastic polyimide, static charge is applied to a molten film, primary cooling is carried out by adhering the film to a cooling roller having a surface temperature in the range of from the glass transition temperature of said polyimide -50° C. to the glass transition temperature -15° C., the film is successively cooled to 60° C. and less without bringing the film into contact with rollers, and is taken up under tension to give a polyimide film. |