Patent ID: 7931947
Filing Date: 2011-04-26
Classification: B29C,B29K,C08B,C08J,C09K,G02B,Y10T

Abstract:
1. A method of producing a cellulose acylate film by melt film forming, comprising the steps of: extruding a cellulose acylate resin into a sheet at an extrusion temperature of 190° C. to 240° C. on a cooling support through a die, using an extruder which has a screw compression ratio of 2.5 to 4.5 and an L/D of 20 to 50; and solidifying the sheet by cooling, wherein the acylate group satisfies the following degree of substitution: 2.5≦A+B<3.0 and 1.25≦B<3.0, wherein A represents the degree of substitution with an acetyl group and B represents the total degree of substitution with a propionyl group, a butyryl group, a pentanoyl group and a hexanoyl group.