Process for making a microporous membrane from a blend containing a poly(etheretherketone)-type polymer, an amorphous polymer, and a solvent
AssigneeThe Dow Chemical Company
InventorsPaul A. Damrow, Robert D. Mahoney, H. Nelson Beck, Mark F. Sonnenschein
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Abstract
The invention relates to a process for preparing a microporous membrane from an unsulfonated poly(etheretherketone)-type polymer by forming a mixture of an unsulfonated poly(etheretherketone)-type polymer, an amorphous polymer, and a plasticizer, heating the resulting mixture, extruding or casting the mixture into a membrane, quenching or coagulating the membrane, and leaching the membrane, while optionally drawing the membrane before, during, and/or after leaching.
Claims23
A process for preparing a microporous membrane from an unsulfonate poly(etheretherketone)-type polymer comprising the steps of:
- A. forming a mixture comprising:
- (i) at least one unsulfonated poly(etheretherketone)-type polymer,
- (ii) a plasticizer comprising at least one organic compound capable of dissolving at least about 10 weight percent of said poly(etheretherketone)-type polymer at the extrusion or casting temperature, and
- (iii) at least one amorphous polymer which is stable at elevated temperatures, which possesses a glass transition temperature of at least about -100.degree. C., and which is at least partially immiscible in said poly(etheretherketone)-type polymer in the presence of said plasticizer;
- B. heating the mixture to a temperature at which said mixture becomes a fluid;
- C. extruding or casting said fluid under conditions such that a membrane is formed;
- D. quenching or coagulating said membrane by passing said membrane through at least one zone under conditions such that said membrane solidifies;
- and
- E. leaching said membrane by passing said membrane through at least one zone under conditions such that at least a portion of said plasticizer for said poly(etheretherketone)-type polymer, at least a portion of said amorphous polymer, or a combination thereof, is removed from said membrane.
Dependencies are inferred from the claim text.