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US 4,048,271 AGranted
Dry process for forming polycarbonate membranes
AssigneeChemical Systems, Inc.
InventorRobert E. Kesting
Life of this patent
Estimating the term…
Abstract
Integral, skinned and unskinned, microporous microfiltration and ultrafiltration, electrophoresis membranes having high void volumes (above 50% void) composed of polycarbonates and copolymers of polycarbonates with polyalkylene oxides and the dry process for producing such membranes are disclosed.
Claims17
The dry process for preparing high void volume, integral, microporous membranes consisting essentially of the steps of:
- preparing a casting solution containing from about 3 to about 10 grams of polycarbonate homopolymers or copolymers having a molecular weight of between about 46,000 ([.eta.] = 75) and 145,000 ([.eta.] = 190) in about 100 ml of solution consisting essentially of from about 30 to about 90 ml of solvent for said polymer and from about 5 to about 50 grams of nonsolvent swelling agent for said polymer,
- casting the solution upon a substrate, and
- allowing the casting solution to evaporate to completion thereby forming an integral, high void volume, microporous membrane.
Dependencies are inferred from the claim text.