Abstract
In wet spinning of cellulose filament, a new coagulation method (net process) which can suppress tension on the filament at low level was successfully devised. An employment of this method for the spinning of new cellulose filament from caustic soda solution made it possible to spin at up to 200 m/min. This process includes a cylindrical shaped spinning funnel used for the viscose rayon and a net, as a supporter of coagulating filament, which runs as the same speed of winding roller. Using this method, we can principally spin the filament at any high speed, because of less hydraulic resistance arising from coagulant, Important factors to obtain high spinning speed and good mechanical properties of as-spun cellulose filament were found to be as follows: (1) Lowering draft ratio by an increase of extrusion speed at spinnerets; (2) reducing the hydraulic resistance at early stage of coagulation by shortening the distance from spinnerets to inlet of the funnel; (3) reducing the hydraulic resistance in the funnel by minimizing the velocity difference between coagulant flow and take-up speed of the filament; (4) drawing the never dried filament by 1.2-1.3 after coagulation. Using the spinning apparatus designed to satisfy these conditions, we obtained the cellulose filament with comparable mechanical properties to commercially available viscose filament at the same spinning speed as that of the viscose (100 m/min).
