Highly aromatic anisotropic polyurea/urethane membranes and their use for the separation of aromatics from non-aromatics
US4828773A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 14, 1987 |
| Grant date | May 9, 1989 |
| Priority date | — |
| Expiry date | Oct 14, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S264/62
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
An anisotropic elastomeric membrane preferably made from polyurea/urethane has been prepared. These anisotropic membranes are made from the corresponding polymeric material by preparing the polymeric material in a good solvent containing less than 5 vol % non-solvent, producing a film of the polymer solution on a support with a maximum pore size less than 20 microns, subjecting the film to conditions such that the solvent vapor pressure-time factor is 1000 mm Hg-min. or less, preferably 200 mm Hg-min or less, most preferably approaching 0 mm Hg-min and quenching the membrane film in a non-solvent yielding a three-layered anisotropic membrane.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.