The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 06, 1990
Filed:
Dec. 07, 1988
National Research Concil of Canada, Ottawa, CA;
Abstract
A method of casting porous membranes of polymeric material is provided wherein the membrane has at least one of the following: a more homogeneous active skin layer for separation purposes with a lower molecular weight cut off, a more homogeneous active skin layer with a sharper molecular weight cut off curve, a relatively thinner active skin layer with a relatively greater flux for a given separation of a substance from a solution thereof, and relatively fewer imperfections through the active skin layer. The method comprises casting a layer of a casting solution on to a support, to provide a cast layer of the casting solution thereon with an exposed skin, then progressively submerging the cast layer in a gelation liquid at a relative velocity of at least 15 cm/second, whereby the exposed skin is gently scrubbed with gelation liquid to continuously remove outwardly diffusing solvent therefrom and dissipate exothermic heat, thus causing gelation of at least a stable, more homogeneous active skin layer, with build-up of a solvent boundary layer between the exposed surface of the layer and the gelation liquid minimized.