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OwnerAndrea Bennett, Michael Mitchell +1inventors
InventorsAndrea Bennett, Michael Mitchell, Peter Carrico
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Process for reducing the content of water-soluble salts of aqueous solutions of polymers containing vinylamine groups by ultrafiltration to achieve a residual salt content of 1 to 10% by weight based on total solution solids in the polymer solution comprising feeding an aqueous salt-containing solution of vinylamine group containing polymers at a polymer concentration of at least 7% by weight to an ultrafiltration unit and removing the water-soluble salts with the permeate from the feed solution by adding thereto less than 4 parts by weight of water per one part by weight of the feed solution, and use of the polymer of the aqueous solutions thus purified as basic water-absorbing resin of multicomponent superabsorbent polymers. Preferably vibratory shear membranes in a diafiltration configuration are used.
A process for reducing a content of water-soluble salts of an aqueous solution of a polymer containing vinylamine groups by ultrafiltration to achieve a residual salt content of 1 to 10% by weight based on total solution solids in the polymer solution, which comprises a step of feeding an aqueous salt-containing solution of a vinylamine group containing polymer at a polymer concentration of at least 7% by weight to an ultrafiltration unit and removing the water-soluble salts with a permeate from the feed solution by adding thereto less than 4 parts by weight of water per one part by weight of the feed solution, wherein the efficiency of the ultrafiltration unit, which is defined as the passage of salt across the membrane, is greater than 100%.
A process for reducing a content of water-soluble salts of an aqueous solution of a polymer containing vinylamine groups by ultrafiltration to achieve a residual salt content of 1 to 10% by weight based on total solution solids in the polymer solution, which comprises feeding an aqueous salt-containing solution of a vinylamine group containing polymer at a polymer concentration of at least 7% by weight to an ultrafiltration unit and removing the water-soluble salts with a permeate from the feed solution by adding thereto less than 4 parts by weight of water per one part by weight of the feed solution, wherein the ultrafiltration unit comprises spiral wound polymer membranes or vibratory shear membranes.
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