Utrafiltration process for the recovery of polymeric latices from whitewater
AssigneeRohm and Haas Company
InventorsRandall G. Buckley, George L. Eastburn, Marion C. Schmitz, Barry R. Breslau, Shawn P. Tansey
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Abstract
Polymer is recovered by ultrafiltration from a whitewater waste stream generated during the production of a polymer latex. The whitewater stream is circulated through an ultrafiltration system in laminar flow, under conditions of shear insufficient to destabilize the whitewater emulsion, and the recovered polymer is in the form of an emulsion which may be blended at significant levels into the original polymer latex without degrading its performance properties.
Claims15
A process for recovering a polymer latex product from a whitewater emulsion which comprises the steps of
- (a) contacting the whitewater emulsion with an ultrafiltration membrane having an active membrane side and a porous support side so that the emulsion flows in laminar flow across the active membrane side under a pressure higher than the pressure on the porous support side, to remove water from the emulsion,
- (b) recirculating the emulsion such that it flows, in laminar flow, across the active membrane side repeatedly until the emulsion has been concentrated to a solids content of 20 weight percent or greater, and
- (c) returning the concentrated emulsion to the polymer latex product,
- wherein the whitewater emulsion is subjected to shear insufficient to destabilize the whitewater emulsion, and wherein the whitewater emulsion is a byproduct formed by diluting the polymer latex product with an aqueous liquid.
A process for recovering a polymer latex product from a whitewater emulsion which comprises the steps of
- (a) contacting the whitewater emulsion with an ultrafiltration membrane under laminar flow conditions, to remove water from the emulsion, and
- (b) recirculating the emulsion such that it flows, in laminar flow, across the active membrane side repeatedly until the emulsion has been concentrated,
- wherein the whitewater emulsion is subjected to shear insufficient to destabilize the whitewater emulsion, wherein the whitewater emulsion is formed by diluting the polymer latex product, and wherein the emulsion so concentrated may be blended into the polymer latex product at a level of at least 5 weight percent without deleterious effect upon performance properties of the product.
Dependencies are inferred from the claim text.