METHOD OF PREPARING CELLULOSE ESTER DOPE, CELLULOSE ESTER FILM AND POLARIZING PLATE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a method of accurately preparing a dope having a specified composition by partially adding a reusable cellulose ester web or returned films. SOLUTION: The method of preparing a cellulose ester dope using a dope preparing process which has a process of transferring a cellulose ester solution containing the returned films, a process of confluence of combining a process of transferring an additive solution with the above process, and a process of mixing both solutions. This method has a means (a) to detect content of the additive in the cellulose ester solution and a means (b) to feed back the detected content of the additive cellulose to the process (C), in the process (B) before the process (G).