| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical film which offers superior durability and reduced permeation and desorption of moisture.SOLUTION: An optical film contains cellulose ester, has a moisture permeability of 350 g/m/day or less (40 μm-thick equivalent), and contains a moisture permeability reducing compound which has a molecular weight of not less than 200 and satisfies an expression (1). (A represents the moisture permeability of the optical film when 10 mass% of the moisture permeability reducing compound is added with respect to the mass of the cellulose ester, and B represents the moisture permeability of the optical film when the cellulose ester content is present but the moisture permeability reducing compound is not added. The moisture permeability is a 40 μm-thick equivalent value of a value measured using the JIS0208 method after the optical film is subjected to a temperature of 40°C and relative humidity of 90% for 24 hours.) Expression (1): A/B≤0.6. |
