CELLULOSE ACETATE FIBRIL, ITS PRODUCTION AND FORMING SPINNERET THEREFOR

摘要

PROBLEM TO BE SOLVED: To obtain a cellulose acetate fibril having a shape, a specific surface area and freeness suitable for an air filter material and to provide both an industrially advantageous method for producing the fibril and a forming spinneret for the fibril. ;SOLUTION: This forming spinneret 1 has a circular section with ≥0.06 mm ϕ and 0.2 mm ϕ diameter and is equipped with a spinning dope flow channel 4 having a delivery outlet 4b of the spinning dope, a coagulant fluid flow channel 8 having a nozzle 8a of a coagulant fluid and a joint part 6 which are opened to the delivery outlet 4b and the nozzle 8a and has a spinning nozzle 7 at the downstream end. An angle θ between a delivery line A of the spinning dope and a jetting line B of the coagulant fluid is 0°θ≤90° and an intersection P of the delivery line A and the jetting line B is positioned at the lower side of the spinning nozzle 7. The spinning dope having ≥10 wt.% and 20 wt.% polymer concentration is spun by the forming spinneret 1 to produce a cellulose acetate fibril having ≥10 m2/g specific surface area, ≥200 ml freeness and ≤10 wt.% of 150 mesh passing material by a screening test.;COPYRIGHT: (C)2000,JPO