PRODUCTION OF CELLULOSE ESTER FILM AND CELLULOSE ESTER FILM

摘要

PROBLEM TO BE SOLVED: To provide a method for obtaining cellulose ester film having excellent quality by preparing cellulose ester dope without using a chlorine-based solvent. SOLUTION: In a method for producing cellulose ester film by a solution casting film forming method using a cellulose ester having a 2-4C acyl group as substituent, a cellulose ester simultaneously meeting following formulas I and II (wherein X is a substitution degree of acetyl group and; Y is a substitution degree of propionyl group and/or butyryl group) is dissolved in a non- chlorine organic solvent containing 0.1-30 wt.% (based on the total weight of all organic solvents) alcohol selected from 1-4C alcohols to prepare dope, and film is formed using the dope: (I) 2.6<=X+Y<=3.0 and; (II) 0<=X<=2.5. A web easily comes off a casting substrate plate and cellulose ester film not having defects such as transverse die lines can be produced.