LENGTHY POLYIMIDE FILM, POLYIMIDE FILM ROLL AND PROCESS FOR PRODUCING THEM
摘要
<p>A lengthy polyimide film is obtained by sequentially performing casting of an organic solvent solution of polyimide precursor substance onto a support to thereby form a film, hot drying of the film so that the difference between imide conversion ratio IM<SUB>A</SUB> of the precursor film on one major surface side (A-surface side) and imide conversion ratio IM<SUB>B</SUB> on the other major surface side (B-surface side) is = 5 and heat treatment of the resultant precursor film. A polyimide film roll is obtained by rolling up the resultant film with the A-surface side inside with a rolling tension of = 100 N so as to attain a radius of curvature ranging from 30 to 600 mm. Both the obtained lengthy polyimide film and polyimide film roll exhibit a curling degree after heating at 300°C of = 10% and a coefficient of variation of film linear expansion coefficient (CV%) of = 25%.</p>
