摘要 |
An acylated cellulose film having a high optical isotropy and uniformity is produced by dissolving an acylated cellulose in a solvent substantially free from water and including, as a principal component, 1,3-dioxolane in a ratio in weight of the acylated cellulose to the solvent of 10/250 to 10/15; spreading the acylated cellulose solution on a film-forming surface of a support; and drying, for example, initially drying the spread solution layer on film-forming surface so as to reduce the content of the residual solvent in the resultant film to 5 to 30% by weight; removing the resultant residual solvent-containing film from the film-forming surface; and finally drying the removed film, while allowing the film to shrink in the transversal direction thereof, at a drying temperature controlled continuously or intermittently to a level satisfying the relationship (I): (Tg'-50 DEG C.)</=T</=(Tg'+20 DEG C.) (I), wherein T is the drying temperature ( DEG C.) and Tg' is a glass transition temperature ( DEG C.) of the solvent-containing film, the temperature Tg' varying in response to the solvent content in the film.
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