POLYACRYLONITRILE FILM AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To obtain a polyacrylonitrile precision filtration membrane excellent in water permeability by forming a polyacrylonitrile film with a min. pore diameter layer having specified particle blocking performance in one face of the film and specifying the porosity of the min. pore diameter layer in a cross section of the film. SOLUTION: The polyacrylonitrile precision filtration membrane is a polyacrylonitrile film with a min. pore diameter layer having 0.01-1μm particle blocking performance in one face of the film and the film has a continuous structure from one face to the other face. The porosity of the min. pore diameter layer in a cross section of the film is as high as 40-90%. The film is produced as follows; a film forming stock soln. consisting of an acrylonitrile polymer, an additive and a solvent which dissolves the polymer and causing microphase separation at >=30 deg.C is cast or ejected in a certain form and solidified. The solvent is preferably N,N-dimethylacetamide and the additive is preferably polyethylene glycol.