To produce a film suppressing admixture of a foreign matter of metal fiber.
A raw material dope 36 containing TAC (cellulose triacetate) and a plasticizer is filtered by a filtration device 57. In the filtration device 57, a filter medium 59 composed of a first layer 59a, a second layer 59b and a third layer 59c in the order of the flow of the raw material dope 36 is arranged. An average diameter of the sintered metal fibers of the first layer 59a is 8μm, that of the second layer 59b is 4μm and that of the third layer 59c is 20μm to constitute the layers 59a-59c. The filter 59 is roasted 2 hours at 400°C and reused. Breakages from the sintered metal fibers in the first and second layers 59a and 59b are filtrated in the third layer 59c to prevent admixture of a foreign matter of a metal fiber in the dope.
KAWASE TSUNEO
TSUKIMI YOSHIHIRO
| JPS6351727B2 | 1988-10-14 | |||
| JPH0693305A | 1994-04-05 | |||
| JP2004074633A | 2004-03-11 | |||
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| JPS6198517A | 1986-05-16 |
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