| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a precision filtration film which has an anisotropic structure, is excellent in strengths and water permeability, and hardly causes clogging in internal pressure filtration. SOLUTION: This method for producing the hollow-fiber precision filtration film comprises causing a film-forming stock solution and an internal liquid to be delivered from a double ring nozzle, followed by passing through an air gap and coagulating them in a coagulation bath. (a) The film-forming stock solution comprises a film-forming polymer, a solvent thereof, and a hydrophilic polymer, the ratio of the hydrophilic polymer to the film-forming polymer being 20-60wt%. (b) The internal liquid comprises water and at least one solvent, the water content being 35-55wt%. (c) The temperature of the film-forming stock solution at the nozzle section is 50°C or higher, and (d) the coagulation bath temperature is 85-100°C. (e) The ratio of the air gap to the spinning speed is set at 0.01-0.1m/(m/min). COPYRIGHT: (C)2004,JPO
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