Porous vinylidene fluoride polymer membrane and process for its preparation
US4384047A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 22, 1982 |
| Grant date | May 17, 1983 |
| Priority date | — |
| Expiry date | Jan 22, 2002 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D71/34
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Vinylidene fluoride polymer ultrafiltration membranes are prepared by casting a sheet of said polymer dissolved in a mixture of a specified solvent and a specified non-solvent, on a smooth substrate, evaporating a portion of the solvent from the sheet, immersing said sheet in a gelation liquid therefore, and optionally, stabilizing the gelled sheet by heat treatment thereof. A porous vinylidene fluoride polymer membrane having smooth, unwrinkled surfaces can be prepared in accordance with the above described process without restraining the membrane during the evaporation and gelation steps by utilizing triethyl phosphate as the solvent.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.