| abstract |
(57) Abstract: A fibril-containing ultrafine fiber containing polyacrylonitrile. SOLUTION: At least 10 polyacrylonitrile is added. When a spinning solution in which a polymer containing not less than 10% by weight is dissolved in a solvent is discharged from a spinning solution discharge port, a coagulant fluid of the polymer is discharged from a coagulant fluid ejection port with respect to a discharge line direction of the spinning solution. Degree, not more than 90 degrees, the polymer is coagulated in a shear flow rate, the formed coagulate is washed, the fibrils having a diameter of 2 microns or less along the fiber axis direction of the main fiber, A surface fibrillated fiber covering most of the main fiber surface is obtained. This main fiber is By beating, it is divided into ultrafine fibers. |