| 摘要 |
PROBLEM TO BE SOLVED: To restrain the generation of smudges due to the precipitation of insolubles on the surface of the support during the film forming. SOLUTION: The dope 20 containing a cellulose acylate, an additive and a solvent is sent to the metal ion capturing apparatus 24 that provides two sheets of the electrode filters 52, 53 in the dope flow passage 51. The electrode filters 52, 53 have each the same shape and consist of the filter main body 55, a metal-made mesh filter and the holding frame 56 consisting of an insulative material. By applying a high voltage to the electrode filters 52, 53 from the high voltage applying part 59 and making each electrode filter 52, 53 function as a positive and a negative pole, a field strength is applied to the dope 20. When the dope 20 passes through the filter main body 55 alkali earth metal ions such as Ca<SP>2+</SP>and Mg<SP>2+</SP>are captured. Casting the dope 20 from which the insolubles are thoroughly removed restrains the smudges from being generated on the surface of the support. COPYRIGHT: (C)2008,JPO&INPIT |
