| abstract |
A film-forming stock solution containing polymetaphenylene isophthalamide, polyvinyl pyrrolidone and an inorganic salt is discharged from a double annular nozzle while keeping the temperature of the film-forming stock solution at 70 ° C. or higher, dried and wet-spun, and then moisturized to obtain a polymeta A phenylene isophthalamide porous hollow fiber membrane is produced. In that case, it is preferable to heat-treat the obtained porous hollow fiber membrane in water at 80 ° C. or higher prior to the moisturizing treatment after dry-wet spinning. The obtained polymetaphenylene isophthalamide porous hollow fiber membrane has a breaking strength of 10 MPa or more and a breaking elongation of 80% or more after wet heat treatment for 1000 hours or more under a moist heat condition of a temperature of 100 ° C. and a humidity of 80%, In addition, the elongation at break is maintained at 80% or more before the wet heat treatment, and it has excellent moisture resistance and humidification performance, so it is effectively used as a humidifying membrane for polymer electrolyte fuel cells. |