| abstract |
The present invention relates to a cellulose ester film with the excellent in retardation expression and more specifically, to a cellulose ester retardation film wherein the total degree of substitution of an acyl group consisting of an acetyl group and a butyl group is 2.24-2.64, E(md) is 3000-4000 N/mm^2, E(td) is 4500-5700 N/mm^2, E(md)<E(td), C(md) is 70-110 μm/m·°C, C(td) is 10-60 μm/m·°C, C(md)>C(td), and {E(md) × C(md)} / {E(td) × C(td)} is 1.6-2.5. At this point, E(md) is a MD direction modulus, E(td) is a TD direction modulus, C(md) is an MD direction CTE, and C(td) is a TD direction CTE. |