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US 8,758,887 B2Granted
Multilayer porous membrane and process
AssigneeEntegris, Inc.
InventorsLarry Yen, Rajnikant B. Patel
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Abstract
A multilayer porous membrane formed of an extrudable polymer is provided. The membrane is formed by co-extruding at least two compositions, each of which comprises a heated porogen and polymer while in contact with each other under conditions to minimize or prevent unstable interfacial flow between extruded layers. In a preferred embodiment, the two compositions are different such that the layers have a different average pore size.
Claims11
A multilayer microporous polymeric membrane, comprising:
- a first layer comprising ultra-high molecular weight polyethylene (UHMW-PE) defining a plurality of pores of a first average pore size;
- a second layer comprising UHMW-PE defining a plurality of pores of a second average pore size that differs from the first average pore size;
- and
- an interface separating the first and second layers,
- wherein the first and second layers and the interface form an integral porous bulk matrix having an open lacy pore structure.
2 more elements
A gel polymer membrane comprising:
- a first layer comprising a first phase-separated ultrahigh molecular weight polyethylene (UHMW-PE) porogen composition;
- a second layer comprising a second phase-separated UHMW-PE porogen composition that differs from the first UHMW-PE porogen composition and is miscible with the first UHMW-PE porogen composition during co-extrusion;
- and
- an interface separating the first and second layers,
- wherein each of the first layer and the second layer has a polymer-rich, porogen-poor phase and a polymer-poor, porogen-rich phase.
2 more elements
Dependencies are inferred from the claim text.