| 摘要 |
PROBLEM TO BE SOLVED: To enable the ultrafiltration film to secure a high fractionation function and a high transmission flow flux by producing the ultrafiltration film such that a densely porous skin layer consisting of polysulfone resin having a specific range of thickness and a loosely porous layer consisting of the same raw material as the densely porous skin layer form a continuous structure. SOLUTION: This polysulfone ultrafiltration film used for a water treatment, etc., has such a structure that the densely porous skin layer 1 consisting of polysulfone resin having 5nm-1000nm thickness and the loosely porous layer 2 consisting of the same raw material as the densely porous skin layer form a continuous structure. When the porous layer part of both an average densely porous skin layer part having L1 thickness and a loosely porous layer part having L2 thickness which corresponds to L1×10 film thickness is observed with a scanning electron microscope by 50,000 magnification and the result is imaged as binary picture with monochromatic picture of 256 gradations, an average luminance ratio (=luminance (L1 )/luminance (L2 )) of the L1 part to the L2 part at 256 gradations is made to be >1.5.
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