Patent ID: 7758777

Claim:
A process for manufacturing a polarizing plate protecting film according to a melt casting method, the process comprising the steps of: providing two film formation compositions, each containing cellulose resin having a total acyl substitution degree of from 2.5 to 2.9, a plasticizer, and 0.01 to 5% by weight of a hindered amine or hindered phenol compound, one of the two film formation compositions having a different content of the plasticizer and a different content of the hindered amine or hindered phenol compound than the other of the two film formation compositions; heat-melting the two film formation compositions to obtain two melts; co-extruding the two melts to form a laminated sheet; cooling the extruded laminated sheet to form a film having a laminated structure; reheating the film; stretching the heated film; and cooling the stretched film, wherein the cellulose resin contains an alkaline earth metal in an amount of from 1 to 50 ppm and a residual sulfuric acid (in terms of sulfur content) in an amount of from 0.1 to 45 ppm, based on the weight of cellulose resin.