| 摘要 |
PURPOSE:To provide an ultrafiltration membrane having a high membrane strength which is easily attached to a module of flat membrane lamination layer type, by forming a selectively permeable membrane layer over the surface of a porous supporting substrate having a flat plate shape with an opening passing through said substrate for the flow of liquid. CONSTITUTION:For example, synthetic high molecular resin such as polyethylene, etc., is sintered to obtain a sheet-like porous supporting substrate 1 having openings 2, 3 for flow of liquid which pass through between opposite surfaces of said substrate. Following application of a membrane-forming liquid to the surface of the substrate 1 by dipping said substrate 1 in the membrane-forming liquid prepared by dissolving polysulfone, etc., is a solvent, thickness of membrane thus applied is made uniform by rotating the substrate 1 in a flat surface of a plate. Further, the substrate 1 is dipped in an aqueous solution so as to obtain a membrane layer 6 on the surface by forming a gel. And next, an ultrafiltration membrane is obtained by cutting off a part for an opening 4 for collecting liquid passing through a membrane. By mounting an annular packing to the outer and inner periphery of the ultrafiltration membrane which has been prepared in such a way as described above, unit of ultrafiltration membrane for use in modular assembling is formed.
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