Cellulose ester film, polarizing plate, liquid crystal display and process for producing cellulose ester film

Abstract

A cellulose ester film has a front retardation Re of from 20 nm to 100 nm relative to light having a wavelength of 590 nm at 25° C. and 60% RH; a retardation Rth in a film thickness direction of from 60 nm to 400 nm relative to light having a wavelength of 590 nm at 25° C. and 60% RH; and a shrinkage factor in a slow axis direction of less than 1% in the range of from a glass transition temperature to a temperature of 40° C. higher than a glass transition temperature.

1 . A cellulose ester film having a front retardation Re of from 20 nm to 100 nm relative to light having a wavelength of 590 nm at 25° C. and 60% RH; a retardation Rth in a film thickness direction of from 60 nm to 400 nm relative to light having a wavelength of 590 nm at 25° C. and 60% RH; and a shrinkage factor in a slow axis direction of less than 1% in the range of from a glass transition temperature to a temperature of 40° C. higher than a glass transition temperature. 
     
     
         2 . The cellulose ester film according to  claim 1 , wherein the cellulose ester film has an acyl group having from 2 to 4 carbon atoms as a substituent and, when a degree of substitution of an acetyl group is defined as DSA and a degree of substitution of a propionyl group or a butyryl group is defined as DSB, is satisfied with a relationship of {2.0≦(DSA+DSB)≦2.9}. 
     
     
         3 . The cellulose ester film according to  claim 2 , wherein the cellulose ester film has an acyl group having from 2 to 4 carbon atoms as a substituent and, when a degree of substitution of an acetyl group is defined as DSA and a degree of substitution of a propionyl group or a butyrl group is defined as DSB, is satisfied with relationships of {2.0≦(DSA+DSB)≦2.9} and {0.4≦DSB≦1.0}. 
     
     
         4 . The cellulose ester film according to  claim 1 , which comprises an aliphatic polyhydric alcohol ester formed from an aliphatic polyhydric alcohol and one or more monocarboxylic acid. 
     
     
         5 . The cellulose ester film according to  claim 1 , which comprises at least one of a retardation developing agent composed of a rod-like or disc-like compound. 
     
     
         6 . The cellulose ester film according to  claim 1 , wherein the film has a thickness of from 20 to 100 μm. 
     
     
         7 . A polarizing plate comprising the cellulose ester film according to  claim 1  stuck onto at least one surface of a polarizer or a polarizing plate. 
     
     
         8 . A liquid crystal display comprising the cellulose ester film according to  claim 1 . 
     
     
         9 . A liquid crystal display comprising the polarizing plate according to  claim 7 .