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US 7,732,528 B2Granted
Water-absorbent crosslinked polymers
AssigneeBASF SE
InventorsBernhard Steinmetz, Peter W. Carrico, Vernon Adey
Life of this patent
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Abstract
Water-absorbent crosslinked polymers bearing acid groups, some or all of the acid groups being present as carboxylate groups having at least two different types of cations as counterions, processes for their preparation and mixtures of water-absorbent crosslinked polymers.
Claims15
A water-absorbent crosslinked polymer particle comprising
- a) at least one copolymerized ethylenically unsaturated monomer bearing acid groups, some or all of the acid groups being present as carboxylate groups having at least two different types of metallic monovalent cations as counterions,
- b) at least one copolymerized crosslinker,
- c) optionally one or more copolymerized ethylenically and/or allylically unsaturated monomer copolymerizable with a) and
- d) optionally one or more water-soluble polymer onto which the monomers a), b), and optional c) are at least partly grafted, wherein said cations are homogenously distributed in said dry crosslinked polymer particle and the acid groups of the copolymerized ethylenically unsaturated monomers are neutralized to an extent in the range from 40 to 90 mol %,
- and wherein the water-absorbent crosslinked particles comprise 0% to 20%, by weight, water.
2 more elements
A mixture of water-absorbent crosslinked polymers comprising at least two water-swellable crosslinked polymers comprising
- a) at least one copolymerized ethylenically unsaturated monomer bearing acid groups, some or all of the acid groups being present as carboxylate groups having one or more types of metallic monovalent cations as counterions,
- b) at least one copolymerized crosslinker,
- c) optionally one or more copolymerized ethylenically and/or allylically unsaturated monomer copolymerizable with a) and
- d) optionally one or more water-soluble polymer onto which the monomers a), b), and optional c) are at least partly grafted,
- wherein said mixture contains a homogenous distribution of at least two of said polymers having different types of metallic monovalent cations as said counterions,
- wherein the water-swellable crosslinked polymers comprise 0% to 20%, by weight, water.
3 more elements
Dependencies are inferred from the claim text.