Ultrafiltration polyimide membrane and its use for recovery of dewaxing aid
AssigneeExxon Research & Engineering Co.
InventorBryce P. Anderson
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Abstract
Polyimide ultrafiltration membranes made using a single solvent and containing a pore forming agent have been produced and have been found to be useful for recovering dewaxing aid used in dewaxing process.
Claims7
A method for producing a polyimide ultrafiltration membrane comprising the steps of dissolving a fully imidized polyimide polymer in a pro solvent and adding a pore forming agent characterized by having 43% more molar volume than the solvent used, a solubility parameter equal to or greater than that of the solvent and a polar end and substantial hydrocarbon character, to produce a casting solution, using said casting solution to produce a thin layer of said polyimide polymer/solvent/pore former, and quenching the layers in a quenching solvent.
Dependencies are inferred from the claim text.