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US 8,540,801 B2Granted
Microporous membrane and method for forming
Assignee3M Innovative Properties Company
InventorsIlyess H. Romdhane, Mikhail S. Mezhirov
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Abstract
The present disclosure describes a method for forming microporous membranes. More specifically, vapor induced phase separation techniques are used for forming multizone microporous membranes having improved material throughput.
Claims14
A method for forming a microporous membrane comprising:
- casting a plurality of dope formulations on a support to provide a multilayer sheet having a first major surface;
- exposing the multilayer sheet to a first relative humidity level such that water vapor diffuses into the first major surface;
- exposing the multilayer sheet to a second relative humidity level such that additional water vapor diffuses into the multilayer sheet effecting a phase separation to provide the microporous membrane, wherein the second relative humidity level is greater than the first relative humidity level;
- washing the microporous membrane;
- and
- drying the microporous membrane.
3 more elements
Dependencies are inferred from the claim text.