Liquid purification or separation – Filter – Material
Reexamination Certificate
2005-02-08
2005-02-08
Walker, W. L. (Department: 1723)
Liquid purification or separation
Filter
Material
C210S500210, C210S490000, C210S651000, C210S653000, C264S288400, C264S290200, C428S421000
Reexamination Certificate
active
06852223
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.
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Chou David
Chou William
Huang James
Lai Juin-Yih
Lee Kueir-Rarn
Armstrong Kratz Quintos Hanson & Brooks, LLP
Menon K S
Walker W. L.
Yeu Ming Tai Chemical Industrial Co., Ltd.
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