Charge modified polyamide membrane
US4702840A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 7, 1986 |
| Grant date | Oct 27, 1987 |
| Priority date | — |
| Expiry date | Apr 7, 2006 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D2325/36
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Surface modified, skinless, hydrophilic, microporous, polyamide membranes are formed by preparing a casting solution comprised of (A) a casting resin system comprised of (a) an alcohol-insoluble polyamide resin, and (b) a cationic, water-soluble, quaternary ammonium, thermosetting, membrane surface modifying polymer, and (B) a solvent system in which the casting resin system is soluble; inducing nucleation of the casting solution by controlled addition of a nonsolvent for the casting resin system under controlled conditions to obtain a visible precipitate of casting resin system particles, thereby forming a casting composition; spreading the casting composition on a substrate to form a thin film; contacting and diluting the film of the casting composition with a liquid nonsolvent system for the casting resin system, thereby precipitating the casting resin system from the casting composition in the form of a thin, skinless, hydrophilic, surface modified, microporous, polyamide membrane; and washing and drying the membrane. The membranes of this invention are characterized by having fine pore ratings, the surface properties thereof being substantially controlled by cationic, quaterna…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.