| 摘要 |
PROBLEM TO BE SOLVED: To suppress the adhesion of foreign substances to the vicinity of a slit from which dope flows out. SOLUTION: Dope for an outer layer in which an additive is added into dope with a polymer, a solvent, and an additive mixed and dope for an underlying layer not containing an additive are prepared. Both kinds of dope are sent to a feed block 50, joined together there, and cast from a slit outlet 85 formed at the tip of a casting die 51 on a traveling support 54 to form cast beads 93 in order to form a double-layer cast film 61 on the support 54. A solvent gas containing the above of the solvent contained in the dope is sent from a blower unit 53 toward the whole region in the width direction of the cast beads 93 which is the slit outlet 85. The concentration of the solvent gas is kept high while its liquefaction in the vicinity of the slit outlet 85 is prevented. Since the dope is prevented from being dried in such an atmosphere, the adhesion of foreign substances is suppressed throughout the whole region in the width direction of the slit outlet 85. COPYRIGHT: (C)2009,JPO&INPIT
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