| 摘要 |
PROBLEM TO BE SOLVED: To provide a cellulose ester film which shows excellent productivity, certainly restrains the incidence of a foreign substance due to a bubble trouble in a dope filtration process, without later generation of the foreign substance and is best-suited for use as a protecting film and a phase difference film for a polarizing plate of a liquid crystal display, and also to provide a manufacturing method of the cellulose ester film. SOLUTION: The manufacturing method of the cellulose ester film is based on a solution cast filming process, and uses a configuration of a dissolving pot 3, a bypass ductwork 6 arranged to a main flow sending ductwork 4 between the dissolving pot and a dope filter 1, and a defoaming device 2 with a stirrer interposed halfway through the bypass ductwork 6. When the filter 1 is initially filled with a dope, the dope is first, introduced into the defoaming device 2, then stirred and defoamed into a dope made up of a finely-divided gelatinized substance of an early filling time. After these procedures, the internal air of the filter 1 and also the internal air bubble of a filter medium are forced out by initially filling the filter 1 with the dope by injection, and then, a cast filming process is performed using the filter 1 which is through with the initial filling. COPYRIGHT: (C)2008,JPO&INPIT |
