| 摘要 |
PURPOSE: To produce a polymer film reduced in anisotropy in orientation with no difference in the characteristics between the central part and the edges thereof. CONSTITUTION: An uncured or solvent-containing film (green sheet) 18, with the the both edges fixed by means of pins 22, is introduced into a heating oven 26 in such a manner as to satisfy the relation a>=b (wherein a is the distance between the heating initiation end and the fixed end of the film; and b is the width of the film) on the drawing, wherein it is gradually heated to about 100-500 deg.C to imidate the green sheet 18, thus giving a polyimide film. The obtained film has little anisotropy in orientation particularly near the edges and uniform distribution of charateristics, mainly the coefficient of linear expansion, coefficient of expansion on absorption of water, elastic modulus, etc., in the widthwise direction. |
