Asymmetric gas separation membranes having improved strength
US4992221A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 24, 1990 |
| Grant date | Feb 12, 1991 |
| Priority date | — |
| Expiry date | Aug 24, 2010 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D2325/38
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A dope for forming membranes and the resulting asymmetric gas separation membranes are disclosed, the membranes having graded density skins which exhibit improved permeability characteristics and increased failure pressure strength. The membranes are produced from a process utilizing membrane forming dopes of complexing solvent systems formulated from two non-solvents and one or more solvents. The non-solvents are chosen one each, from non-solvents grouped according to non-solvent strength, i.e., one strong non-solvent and one weak non-solvent which are combined with one or more solvents in an acid:base complex solvent system for dissolving high weight percent total solids of membrane forming polymers. The process for forming the membranes is also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.