Degradation of superabsorbent polymer via oxidative degradation
AssigneeThe Procter & Gamble Company
InventorArsen Simonyan
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Abstract
A method for degrading crosslinked and poly(acrylic acid)-based superabsorbent polymer (SAP) into soluble polyacrylic acid polymers is disclosed. Degradation is achieved with an oxidative water-soluble salt comprising at least one cation and at least one anion.
Claims19
A method for degrading crosslinked, poly(acrylic acid)-based superabsorbent polymer (SAP) into soluble polyacrylic acid polymers, comprising:
- a) providing SAP;
- b) providing an oxidative water-soluble salt comprising at least one cation and at least one anion, wherein the at least one anion is selected from the group consisting of:
- peroxydisulfate, peroxymonosulfate, peroxydicarbonate, peroxy diphosphate, peroxydiborate, and mixtures thereof;
- c) providing an aqueous carrier;
- d) mixing the SAP with the oxidative water-soluble salt and the aqueous carrier to form a mixture;
- e) heating the mixture to a temperature of from about 30° C. to about 200° C. to degrade the SAP into soluble polyacrylic acid polymers;
- f) providing a mesh and capturing the SAP on the mesh;
- g) degrading the SAP captured on the mesh, wherein the SAP is captured by the mesh until the SAP has degraded sufficiently to pass through the mesh;
- wherein a ratio of the oxidative water-soluble salt to SAP is from about 0.001 g to about 0.05 g of oxidative salt per 1 gram of SAP.
A method for degrading crosslinked, poly(acrylic acid)-based superabsorbent polymer (SAP) into soluble polyacrylic acid polymers, comprising:
- a) providing SAP;
- b) providing an oxidative water-soluble salt comprising at least one cation and at least one anion, wherein the at least one anion is selected from the group consisting of:
- peroxydisulfate, peroxymonosulfate, peroxydicarbonate, peroxydiphosphate, peroxydiborate, and mixtures thereof, wherein the oxidative water-soluble salt is substantially free of other anions;
- c) providing an aqueous carrier;
- d) mixing the SAP with the oxidative water-soluble salt and the aqueous carrier to form a mixture;
- and
- e) heating the mixture to a temperature of from about 30° C. to about 200° C. at a pH of from about 3 to about 7 to degrade the SAP into soluble polyacrylic acid polymers,
- f) passing the mixture through a mesh so that the soluble polyacrylic acid polymers pass through the mesh and retaining the SAP that has not degraded on the mesh until it degrades,
- wherein a ratio of the oxidative water-soluble salt to SAP is from about 0.001 g to about 0.05 g of oxidative salt per 1 gram of SAP, and
- wherein the soluble polyacrylic acid polymers comprise an average molecular weight, Mw, of from about 10 kDa to about 10 MDa.
A method for degrading crosslinked, poly(acrylic acid)-based superabsorbent polymer (SAP) into soluble polyacrylic acid polymers, consisting essentially of:
- a) providing SAP;
- b) providing an oxidative water-soluble salt comprising at least one cation and at least one anion, wherein the at least one anion is selected from the group consisting of:
- peroxydisulfate, peroxymonosulfate, peroxydicarbonate, peroxy diphosphate, peroxydiborate, and mixtures thereof;
- c) providing an aqueous carrier;
- d) mixing the SAP with the oxidative water-soluble salt and the aqueous carrier to form a mixture;
- and
- e) heating the mixture to a temperature of from about 30° C. to about 200° C. to degrade the SAP into soluble polyacrylic acid polymers,
- f) passing the mixture through a mesh so that the soluble polyacrylic acid polymers pass through the mesh and retaining the SAP that has not degraded on the mesh,
- wherein a ratio of the oxidative water-soluble salt to SAP is from about 0.001 g to about 0.05 g of oxidative salt per 1 gram of SAP.
Dependencies are inferred from the claim text.