Patent ID: 8883056
Filing Date: 2014-11-11
Classification: C08J

Abstract:
1. A method for preparing a cellulose-based film, the method comprising the steps of: preparing a dope of a composition comprising 5-15 wt % of a pulp having an alpha-cellulose content of more than 90% and 85-95 wt % of an aqueous N-methylmorpholine-N-oxide solution; extruding the dope from a die onto a running support; casting the extrudate to form a sheet; washing the cast sheet with water to remove N-methylmorpholine-N-oxide therefrom; and drying the washed sheet, wherein the running support is placed with a gap from the die and immersed partially in a solidifying bath so that the extrudate from the die is brought to contact with the running support at a position of the running support where the running support is not immersed in the solidifying bath; and wherein the running support is allowed to run while being partially immersed in the solidifying bath containing N-methylmorpholine N-oxide, the concentration of said N-methylmorpholine N-oxide being controlled to be 3˜50%, so that the casting of the extrudate is carried out in air first and then in the solidifying bath.