Method of producing of cellulose ester film

摘要

In order to produce a cellulose ester film (22) constructed of a front layer (22a), an intermittent layer (22b) and a rear layer (22c), a dope solution is doped on a supporter (5). In at least one of the front layer (22a) and the rear layer (22b), a mass ratio of a cotton linter to a wood pulp (cotton linter/wood pulp) is between 5/95 and 0/100, and a solvent of the dope contains more than 15 wt.% alcohols and hydrocarbons whose carbon number each is 1-10. Further, a ratio of a solid content density of a solution for forming the front layer (22a) and the rear layer (22b) to a solid density of a solution for forming the intermittent layer is less than 0.9 wt.%, and a total thickness of the solutions for front and rear layers (22a, 22b) is more than 5% of the dope ribbon.