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AssigneeAMCOL International Corporation
InventorsPeter W. Carrico, Bala V. Nathan
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A new and improved method of manufacturing an acrylic acid superabsorbent polymer, that is manufactured by any known technique, except that the acrylic acid monomer is polymerized to substantial completion before neutralization, and neutralization is accomplished by admixing a solid, e.g., powdered or granular, neutralizing agent into the acrylic acid polymer. Preferably, the neutralizing agent is a solid, non-hydroxide neutralizing agent, such as sodium carbonate, potassium carbonate, ammonium carbonate or mixtures thereof. Cross-linking may be accomplished during polymerization, simultaneously with neutralization, or cross-linking may be carried out in a separate processing step subsequent to neutralization, or both.
A method of manufacturing a polymer of acrylic acid comprising polymerizing an aqueous solution of unneutralized acrylic acid and, after polymerization is substantially complete and the unneutralized acrylic acid forms an unneutralized poly-acrylic acid gel, homogeneously and intimately mixing a solid, non-hydroxyl neutralizing agent into the gel in an amount sufficient to neutralize at least 25 mole percent of the acid moieties of said polyacrylic acid, and cross-linking said polyacrylic acid gel in an amount sufficient to make said polymer water-insoluble.
Dependencies are inferred from the claim text.