摘要 |
PURPOSE: To remove lumen stabilizers (lumen fillers) and/or undesired auxiliary processing agents without using fluorinated chlorohydrocarbon, or the like, by extracting a hollow fiber or a hollow fiber membrane with supercritical gases. CONSTITUTION: A hollow fiber or a hollow fiber membrane containing lumen fillers such as isopropyl myristate or an auxiliary processing agents, or the like, is extracted with a supercritical gas such as CO2 , or the like, to remove the lumen fillers or the auxiliary processing agents, or the like. A residual content of isopropyl myristate, which is a lumen filler suitable for cellulose fibers, can be reduced to less than 500 ppm, preferably less than 300 ppm. |