Hollow-fiber porous water filtration membrane of vinylidene fluoride resin and process for producing the same
US7455772B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 8, 2005 |
| Grant date | Nov 25, 2008 |
| Priority date | — |
| Expiry date | Jun 8, 2025 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/249978
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A vinylidene fluoride resin having a weight-average molecular weight as relatively high as 300,000 or higher is mixed with a plasticizer and good solvent for the vinylidene fluoride resin to obtain a composition. A molten extrudate of the composition in a hollow-fiber membrane state is contacted, on its outer side, with a cooling liquid inert to the vinylidene fluoride resin to thereby cool the extrudate. During the solidification, the vinylidene fluoride resin is moderately and mildly crystallized. Thus, a hollow-fiber porous vinylidene fluoride resin membrane is produced which has a high crystallinity represented by an enthalpy of crystal melting 58 J/g or higher. The hollow-fiber porous membrane obtained is excellent in mechanical strength represented by tensile strength and elongation at break and in chemical resistance. It is effectively used as a water microfiltration membrane.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.