Method for manufacturing cellulose ester film, and cellulose ester film, optical film, polarizing plate and liquid crystal display device using the same

Abstract

A method for manufacturing a cellulose ester film comprising the steps of 1) mixing a cellulose ester exhibiting a water content of not greater than 3.0 weight %, at least one plasticizer selected from the groups A and B in an amount of one to thirty weight % of the cellulose ester, and at least one additive selected from the groups of C and D in an amount of 0.01 to 5 weight % of the cellulose ester to obtain a mixture, group A: ester plasticizers formed from a polyhydric alcohol and a monohydric carboxylic acid; group B: ester plasicizers formed from a polyhydlic carboxylic acid and a monohydric alcohol; group C: hindered phenol anti-oxidants; group D: hindered amine light stabilizers, 2) heating to melt the mixture at a temperature (Tm) of between 150 and 300° C., and 3) forming a cellulose ester film with a melt casting method employing the melted mixture.

Dependencies are inferred from the claim text.