ALKALI SAPONIFICATION METHOD FOR CELLULOSE ACYLATE FILM, A SURFACE SAPONIFIED CELLULOSE ACYLATE FILM AND AN OPTICAL FILM UTILIZING THE SAME

摘要

The invention is to provide an alkali saponification method for uniformly and stably saponifying a cellulose acylate film, to provide a surface saponified cellulose acylate film adapted for an optical compensation sheet for a large-sized liquid crystal display apparatus without a display defect, and to provide a alkali saponified cellulose acylate film adapted for an optical compensation sheet with an appropriate adhesion between a transparent substrate and an orienting film. There is provided an alkali saponification method for cellulose acylate film characterized by alkali saponification of a cellulose acylate film with an alkali solution, particularly an alkali saponification method for achieving selective saponification by coating the alkali solution on one surface only of the film, and a cellulose acylate film processed by such alkali saponification method.