Membranes of acrylonitrile polymers for ultrafilter and method for producing the same
Abstract
Abstract Membranes of acrylonitrile polymers having water-permeability greater than 0.2 ml/cm 2 .min.atm and useful as an inexpensive superior ultrafilter, comprising (1) a porous layer or layers existing near and on the surfaces of said membranes, the average sizes of pores contained in said porous layer or layers and existing on each of assumptive parallel planes to the surfaces of said membranes, having such a gradient that said average sizes become smaller toward the surfaces of said membranes, and (2) a reticulate porous layer adjacent to said porous layer or layers (1) and containing therein a succession of voids of cylindrical shape or revolving ellipsoid shape having diameters of 5 - 50μ and lengths of at least 10μ, are prepared by dissolving an acrylonitrile polymer in an aqueous solution of nitric acid of 65 - 95% by weight concentration, casting the resulting solution on a support followed by coagulation in a coagulation bath, or extruding the resulting solution from a slit into a coagulation bath, the coagulation bath being water alone or a nitric acid aqueous solution of 30% by weight or less.
Inventors
- 👤 Yasuo Hashino
- 👤 Masatsugu Yoshino
- 👤 Hitoshi Sawabu
- 👤 Sukeo Kawashima
Bibliographic Details
Claims Analysis
Total Claims: 7References Cited (Backward Citations)
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| 7.5 Years (Year 8) | 1983-01-19 | 1983-07-21 | 1984-01-20 | $3760.00 | Window Closed / Lapsed |
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