| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an alkali saponification method for a polymer film, using a surfactant which does not remain on the saponified polymer film after stabilizing extracted matter in saponification and washing-off steps, to provide a surface-saponified cellulose acylate film obtained by the above method, and to provide an optical film, a polarizing plate and a liquid crystal display device, respectively. <P>SOLUTION: The alkali saponification method for a polymer film comprises conducting an alkali saponification treatment of the polymer film using an aqueous alkali solution containing at least an alkali agent and a surfactant; wherein the surfactant is a nonionic surfactant represented by general formula (1): R<SB>1</SB>-L<SB>1</SB>-Q<SB>1</SB>with an HLB number of 17.0-19.0, and its concentration in the alkali solution is 0.1-1.0 mass%. <P>COPYRIGHT: (C)2009,JPO&INPIT |
