CELLULOSE ACETATE FILM AND ITS MANUFACTURE

摘要

PROBLEM TO BE SOLVED: To obtain a cellulose acetate film having excellent dimensional stability adapted to use of a polarizing plate protective film. SOLUTION: Dope in which cellulose acetate is dissolved in organic solvent is cast on a support to form a film. Then, the film is peeled from the support in the state that an amount of the solvent of less than 60 wt.% is contained in the film. The peeled film is heat treated at 120 to 135 deg.C for 4 min or more so that shrinkage factor of a casting direction after treatment for 120 hours at 90 deg.C and 5% of relative humidity and shrinkage factor of a casting direction after treatment for 120 hours at 90 deg.C and 65% of relative humidity are all 0.3% or less. Such a cellulose acetate film is manufactured.