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AssigneeNational Starch and Chemical Corporation
InventorsStuart H. Ganslaw, Howard G. Katz
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The aqueous dispersibility of a water-absorbent composition of matter is improved by a surface treatment which ionically complexes the surface thereof to a moderate degree. A dispersion is formed comprising a water-absorbent composition of matter based on an anionic poly-electrolyte, at least one polyvalent metal cation, and a dispersing medium in which the composition of matter is substantially insoluble. The dispersion is maintained within a given temperature range for a period of time sufficient to ionically complex the exposed surface of the composition of matter, and the dispersing medium is then removed. The product is characterized by a linkage density which is greater at the surface thereof than in the interior thereof and by the presence of ionic linkages at the surface thereof.
A process for surface treating a water-absorbent composition of matter to improve its aqueous dispersibility comprising the steps of
A water-absorbent composition of matter comprising water-dispersible water-absorbent particles based on an anionic poly-electrolyte, each of said particles having a linkage density at the particle surface greater than the linkage density in the particle interior, the linkages at the particle surface comprising at least in part ionic complexing of said anionic poly-electrolyte by polyvalent metal cations.
Dependencies are inferred from the claim text.