| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of a film with a high quality having no optical unevenness by suppressing an increasing in an organic matter adhered to the surface of a substrate. SOLUTION: A casting film 33 is formed by casting a dope 21 on a casting drum 32 the surface of which is made to be cooled. The casting film 33 is peeled and before the dope is casted, cleaning gas containing dry ice particles is brown to the surface of the casting drum 32 with a drum cleaning unit 41. The dry ice particles collide to the surface of the casting drum 32, and the colliding energy is effective of removing from the surface an organic matter adhered on the casting drum 32. The organic matter mainly contains aliphatic acid aliphatic acid ester, metal salt of aliphatic acid. Befor the increase of the amount of the organic matter, it is removed and therefore isn't transmitted onto the surface of the casting film. Thus a film 20 with a high quality having no optical unevenness is produced without lowering the productivity. COPYRIGHT: (C)2009,JPO&INPIT |
