Cellulose ester film, production method of the same, film employed in liquid crystal display member, and polarizing plate

Abstract

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 . A film employed in a liquid crystal display member 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 film employed in a liquid crystal display member of  claim 1  wherein the film is a polarizing plate protective film.  
     
     
         3 . The film employed in a liquid crystal display member of  claim 1  wherein the film comprises a cellulose ester film.  
     
     
         4 . The film employed in a liquid crystal display member of  claim 3  wherein average degree of substitution of the cellulose ester film is 2.88 to 3.00.  
     
     
         5 . The film employed in a liquid crystal display member of  claim 3  wherein cellulose ester film is a film employing a composition ratio of wood pulp cellulose/cotton linter cellulose=60/40 to 0/100 in terms of weight ratio.  
     
     
         6 . The film employed in a liquid crystal display member of  claim 3  wherein cellulose ester film is comprised of lower fatty acid esters of cellulose.  
     
     
         7 . The film employed in a liquid crystal display member of  claim 1  wherein a length of the film is at least 1000 m.  
     
     
         8 . The film employed in a liquid crystal display member of  claim 7  wherein a length of the film is at least 1500 m.  
     
     
         9 . The film employed in a liquid crystal display member of  claim 1  wherein tear strength of the film is at least 7 g.  
     
     
         10 . The film employed in a liquid crystal display member of  claim 1  wherein haze of the film is no more than 0.5 percent.  
     
     
         11 . The film employed in a liquid crystal display member of  claim 1  wherein retardation value of the film is below 10 nm.  
     
     
         12 . The film employed in a liquid crystal display member of  claim 1  wherein the film comprises a plasticizer in an amount of 1 to 30 percent by weight.  
     
     
         13 . The film employed in a liquid crystal display member of  claim 1  wherein the film comprises an UV absorber in an amount of 0.01 to 5 percent by weight.  
     
     
         14 . A polarizing plate comprising a polarizer and a polarizing plate protective film wherein thickness of the polarizing plate protective film is 20 to 60 μm and variation in the film thickness of the polarizing plate protective film is within ±3.0 percent of the standard film thickness.  
     
     
         15 . The polarizing plate of  claim 14  wherein the polarizing plate protective film is provided on each of both sides of the polarizer.  
     
     
         16 . The polarizing plate of  claim 14  wherein the polarizing plate protective film comprises a cellulose ester film.  
     
     
         17 . The polarizing plate of  claim 14  wherein average degree of substitution of the cellulose ester film is 2.88 to 3.00.  
     
     
         18 . A liquid crystal display member comprising a first polarizing plate, liquid crystal cell, and a second polarizing plate provided in the interior of said first polarizing plate and the liquid crystal cell,  
       the first polarizing plate having 
 a first polarizer,  
 a first protective film provided on a surface of the first polarizer which does not face the liquid crystal cell,  
 a second protective film provided on a surface of the first polarizer which faces the liquid crystal cell,  
 the second polarizing plate having  
 a second polarizer,  
 a third protective film provided on a surface of the second polarizer which faces the liquid crystal cell,  
 a fourth protective film provided on a surface of the second polarizer which does not face the liquid crystal cell,  
 wherein at least one of the first protective film, the second protective film, the third protective film and the fourth protective film has film thickness of 20 to 60 μm and variation in the film thickness within ±3.0 percent of the standard film thickness.  
 
     
     
         19 . The liquid crystal display member of  claim 18  wherein the protective film having film thickness of 20 to 60 μm comprises a cellulose ester film.  
     
     
         20 . The liquid crystal display member of  claim 18  wherein average degree of substitution of the cellulose ester film is 2.88 to 3.00.