PURPOSE: To provide the titled film having excellent transparency, high mechanical strength, and excellent dimensional stability, by dissolving a cellulose triacetate in N-methyl-2-pyrrolidone at a specific concentration, and casting the obtained dope.
CONSTITUTION: A cellulose triacetate (having a bonded acetylation degree of 56W62%, preferably 59W62%) is dissolved in N-methyl-2-pyrolidone at a concentration of 3W50wt%, preferably 15W25wt%, and the solution is heated at 100W180, preferably 120W160°C, cast through a casting die on a substrate, dried partly at 100W130°C, peeled off from the substrate when the residual volatile content reaches 20W10%, and quenched with air of -7W+4°C. The film is cooled in the above state for ≥30sec, and the residual volatile component is removed at 80°C to obtain a cellulose triacetate film having a thickness of preferably 30W300μm.
TAKEDA AKIRA
SHINAGAWA YUKIO
Next Patent: POROUS MOLDED ARTICLE OF CELLULOSE ACETATE AND PRODUCTION THEREOF