| 摘要 |
This invention provides, for example, a highly planar optical film that can be used, for example, in phase difference films for liquid crystal display devices, and a process for producing the optical film by a melt casting film forming method. A melt containing a cellulose resin is extruded from a casting die (4) onto a rotary support (5) (a cooling roll) . A nip pressing rotator (6) (touch roll) is energized against the rotary support (5). The melt is nip pressed between the nip pressing rotator (6) and the rotary support (5) to eliminate a die line and to eliminate uneven thickness. To this end, nip can be formed between the nip pressing rotator and the rotary support. The planarity of the film can be effectively corrected by setting the linear pressure of an elastic roll and the temperature of the melt immediately before nip pressing to respective predetermined ranges. |
