Porous membrane structure and method
US6410084B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 10, 1999 |
| Grant date | Jun 25, 2002 |
| Priority date | — |
| Expiry date | Dec 10, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/269
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A method of treating a membrane (16) comprises the steps of providing a membrane (16) with a structure of node (22) and fibrils (24). Surfaces of the nodes (22) and fibrils (24) define a plurality of pores (26) extending through the membrane (16). The membrane (16) is made from an expanded polytetrafluoroethylene material. A water-based dispersion of oleophobic fluoropolymer solids in a water-soluble solvent is provided. The dispersion has surface tension and relative contact angle properties such that the diluted dispersion is incapable of wetting the polytetrafluoroethylene material of the membrane (16). The dispersion is diluted with a liquid wetting agent so the diluted dispersion can wet the membrane (16). Surfaces of the nodes (22) and fibrils (24) are coated with the solids in the diluted dispersion. The wetting agent material and other fugitive material are removed. Solids in the diluted dispersion are thermally coalesced on surfaces of the nodes (22) and fibrils (24) without completely blocking the pores (26) in the membrane (16).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.