Process for preparing a membrane
US4248913A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 24, 1979 |
| Grant date | Feb 3, 1981 |
| Priority date | — |
| Expiry date | May 24, 1999 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D71/383
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A process for preparing a microporous polymeric membrane, which process comprises preparing a polymer-casting solution, casting a thin film of the casting solution on a support base, allowing partial evaporation of the solvent from the cast film for a predetermined period of time and contacting the partially evaporated cast film with the microporous leaching liquid to provide a membrane, the improvement which comprises: providing a casting solution which comprises a vinylidene fluoride polymer and from about 35 to about 85% by weight of a vinyl acetate polymer; and hydrolyzing the acetate polymer after the leaching step to convert the acetate groups to hydroxyl groups, to provide an improved membrane having good mechanical strength and hydrophilic properties.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.