Dispersing casting of integral skinned highly asymmetric polymer membranes
US4774039A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 19, 1986 |
| Grant date | Sep 27, 1988 |
| Priority date | — |
| Expiry date | Nov 19, 2006 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D2325/0283
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
There is disclosed, in one aspect, an improved highly asymmetric membrane comprising a skin and a porous asymmetric support. The skin contains pores which have an mean pore diameter of from about 0.005 to about 3.0 microns and the asymmetric support comprises a reticulated structure which contains pores which have pore diameters of from about 10 to about 20,000 times as large as the pore diameter of the pores of the skin. The membrane has a bulk porosity greater than about 70%. In another aspect, there is disclosed a process for preparing these membranes. This process comprises casting a polymer dope while the dope is in an unstable liquid dispersion condition. The concentration of polymer in the polymer dope should be high enough to produce a coherent membrane yet low enough to form a substantially all-reticulated structure within the asymmetric support. The membranes are characterized by high flow rates, excellent retention properties, and improved resistance to fouling.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.