Asymmetric porous polytetrafluoroethylene membrane and process for preparing the same
US6852223B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 2002 |
| Grant date | Feb 8, 2005 |
| Priority date | — |
| Expiry date | Apr 18, 2023 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/3154
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The present invention relates to an asymmetric porous polytetrafluoroethylene membrane comprising a dense skin layer and a continuously foamed porous layer, (1) the dense skin layer having a surface roughness Ra of 20 to 165 nm; (2) the dense skin layer having a contact angle for water of 120 to 135°; (3) the porous layer having a maximum pore diameter of 0.03 to 1.0 μm; and (4) the membrane having a total porosity of 20 to 70%. The asymmetric porous PTFE membrane has an ability to separate each liquid component from a liquid-liquid homogeneous mixture in addition to known properties such as water permeability resistance, gas permeability, sealing property and electric property, wherein change of these properties over time is small.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.