| abstract |
A polyimide film of 20 to 125 μm thick composed of aromatic polyimide prepared from an aromatic tetracarboxylic acid component (composed mainly of 3,4,3′,4′-biphenyltetracarboxylic acid or its derivative) and an aromatic diamine component (composed mainly of p-phenyl-enediamine) and containing a micro-granular filler of metal atom-containing inorganic material, can be so denatured on its surfaces that an amount of the metal atom and a ratio of oxygen/carbon would increase by 0.03 to 1.0 atomic % and 0.01 to 0.20, respectively, on the processed surfaces, upon running in a gaseous mixture of argon and hydrogen between a plurality of activated plasma discharge electrodes arranged in a double line under such condition that the running polyimide film is free from contact with the electrodes. |