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US 7,459,501 B2Granted
Superabsorbent polymers in agricultural applications
AssigneeAbsorbent Technologies, Inc.
InventorsWilliam McKee Doane, Steven William Doane, Milan H. Savich
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Abstract
Superabsorbent polymer (SAP) products for use in agricultural applications, and methods of making and using the same are disclosed. Certain of the SAPs include a monomer or a mixture of monomers, other than acrylonitrile, that is graft polymerized onto a starch in the presence of an initiator to form a starch graft copolymer that is cross-linked and the SAP product is isolated.
Claims9
A method for preparing a superabsorbent polymer, comprising:
- graft polymerizing a monomer onto a starch in the presence of an initiator to form a starch graft copolymer, wherein the monomer is at least one of the following:
- acrylic acid, acrylamide, methacrylamide, 2-acrylamido-2-methyl-propanesulfonic acid, methacrylic acid, vinyl sulfonic acid, ethyl acrylate, potassium acrylate, derivatives thereof or mixtures thereof;
- adding a cross-linking agent to cross-link the starch graft copolymer;
- isolating the starch graft copolymer by extruding the starch graft copolymer into strands after cross-linking the starch graft copolymer;
- applying an alcohol to the strands to reduce tackiness of the extruded strands, the alcohol chosen from:
- methanol, ethanol, propanol or isopropanol;
- and
- forming granules of starch graft copolymer from the extruded strands.
5 more elements
A method for preparing a superabsorbent polymer product for agricultural applications, comprising:
- graft polymerizing a mixture of acrylic acid and acrylamide onto a starch in the presence of an initiator to form a starch graft copolymer;
- adding a cross-linking agent to form a cross-linked starch graft copolymer;
- adjusting a pH of the cross-linked starch graft copolymer to within a pH range of about 6.0 and about 8.0;
- isolating the superabsorbent polymer product through extruding the cross-linked starch graft copolymer;
- and
- applying an alcohol to the extruded cross-linked starch graft copolymer to reduce its tackiness, the alcohol chosen from:
- methanol, ethanol, propanol or isopropanol.
4 more elements
Dependencies are inferred from the claim text.