Mitsui Petrochemical Industries, Ltd.

Noriake Ohishi

Hiroaki Nakagawa

Masahiro Kondo

Disclosed is a process for the preparation of cellulose ester films, which comprises dissolving a cellulose ester in an organic solvent, coating the solution on a substrate under rotation and peeling the film formed on the substrate from the substrate, wherein a second organic solvent having a compatibility with the organic solvent and being a poor solvent to the cellulose ester is added to the organic solvent solution of the cellulose ester to precipitate a cellulose ester having a high molecular weight in the cellulose ester, the cellulose ester having a high molecular weight is separated from the solution, and the remaining cellulose ester solution is formed into a cellulose ester film by the rotational film-forming menthod. The cellulose ester film prepared according to this process is excellent in the thickness uniformity and free of color nonuniformity or streaks and has good optical properties.

Process for preparation of cellulose nitrate films

Disclosed is a process for the preparation of cellulose ester films, which comprises dissolving a cellulose ester in an organic solvent, coating the solution on a substrate under rotation and peeling the film formed on the substrate from the substrate, wherein a second organic solvent having a compatibility with the organic solvent and being a poor solvent to the cellulose ester is added to the organic solvent solution of the cellulose ester to precipitate a cellulose ester having a high molecular weight in the cellulose ester, the cellulose ester having a high molecular weight is separated from the solution, and the remaining cellulose ester solution is formed into a cellulose ester film by the rotational film-forming method. The cellulose ester film prepared according to this process is excellent in the thickness uniformity and free of color nonuniformity or streaks and has good optical properties.

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Iwakuni, Japan

Noriake Ohishi