| 摘要 |
In solution casting, dope containing a polymer and a solvent is cast on to a support to form a cast film. The cast film is stripped from the support to obtain a polymer film of cellulose ester, for example, cellulose acetate propionate (CAP). The polymer film is stretched. While the polymer film is stretched, tension of 80 N/m or more is applied thereto in a stretching direction. Polymer film surface temperature thereof is set equal to or more than a glass transition temperature Tg thereof. Furthermore, before stretching the polymer film, the polymer film stripped from the support is dried. After stretching the polymer film, the polymer film is dried. Also, the solution casting process is according to multi casting of plural dopes at one time together for plural cast films in the polymer film.
|
