| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a smooth film by suppressing and eliminating the uneven thickness of a cast film. SOLUTION: First and second dopes 61 and 62 different from each other are cast on a traveling casting support 86 and the cast film 87 is gelled on its exposed surface side to form a part of the cast film 87 as a gel layer 171. At that time, the gel layer 171 having contraction force larger than the surface tension of the second dope 62 is formed. By this constitution, the cast film 87 has self-smoothness by the contraction force of the gel layer 171 and is peeled from the casting support to obtain a dried film having no uneven thickness but having a good surface state. COPYRIGHT: (C)2007,JPO&INPIT |
