Cellulose ester film, production method of the same, film employed in liquid crystal display member, and polarizing plate
A film employed in a liquid crystal display member is disclosed. The film has film thickness of 20 to 60 μm and variation in the film thickness within ±3.0 percent of the standard film thickness.
1. An apparatus for forming an optical film, comprising:
a casting section to cast a dope onto a support;
a peeling section peeling a film from the support;
a tenter drying section drying the peeled film; and
a winding section winding film in a roll over a length of at least 1000 m,
wherein the film has film thickness of 20 to 60 μm and variation in the film thickness within ±3.0 percent of the standard film thickness.
2. The apparatus of claim 1 , wherein the support is a drum.
3. The apparatus of claim 1 , wherein the dope comprises cellulose ester.
4. A method for forming an optical film, comprising:
casting a dope onto a support to form a film on the support;
peeling the film from the support;
drying the peeled film at a tenter drying section; and
winding the film in a roll over a length of at least 1000 m,
wherein the film has film thickness of 20 to 60 μm and variation in the film thickness within ±3.0 percent of the standard film thickness.
5. The method of claim 4 , wherein the support is a drum.
6. The method of claim 4 , wherein the dope comprises a cellulose ester compound.
7. The method of claim 4 , wherein the cellulose ester compound is composed of ration of wood pulp cellulose/cotton linter cellulose=60/40 to 0/100 by weight.
8. The method of claim 7 , wherein cellulose ester comprises a lower fatty acid esters of cellulose.
9. The method of claim 4 , wherein the dope comprises benzotriazole.
10. The method of claim 4 , wherein the dope comprises a plasticizers having a solidifying point of no more than 20° C.
11. The method of claim 7 , wherein the cellulose ester has an acetated degree of 54 to 62 percent.
12. The method of claim 11 , wherein the cellulose ester has an acetated degree of at least 59 percent.
13. The method of claim 4 , wherein the winding speed is not less than 30 m/minutes.
14. The method of claim 4 , wherein the film is a polarizer protective film, a phase difference film, a reflective film, a visibility increasing film, a glare minimizing film, a non-reflective film, or an antistatic film.