Verfahren zur Herstellung von Cellulose-Flachfolien

摘要

The invention relates to a process for producing flat cellulose films by the dry/wet extrusion method from a solution of cellulose in a water-containing N oxide of a tertiary amine, especially N-methylmorpholine-N-oxide, by extruding the solution through a die with an annular nozzle into a medium which does not precipitate the cellulose, drawing the extruded solution tube in said medium and precipitating the cellulose from the solution tube by agitation with a precipitating medium without substantial extension. The solution tube is drawn at the same time in the extrusion direction as it travels from the annular nozzle outlet to the precipitation medium, expanded by pressurised gas acting inside the tube in a ratio in the range from 1:1 to 1:10 and the precipitated tube film is cut down the edge after washing out the amine oxide, post-treatment and drying, and the film web is wound together or separately on one or two winding positions of a roll winding machine. The process facilitates the production of flat cellulose films with improved properties in use, especially improved mechanical properties, using the amine oxide process.