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US 8,618,206 B2Granted
Process for producing water-absorbing polymer particles with low caking tendency and high absorption under pressure
AssigneeBASF SE
InventorsThomas Daniel, Christophe Bauduin, Norbert Herfert
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Abstract
A process for producing water-absorbing polymer particles with low caking tendency and high absorption under pressure, comprising polymerization of a monomer solution or suspension, drying of the resulting polymer gel, grinding, classifying, thermal surface postcrosslinking and coating with silicon dioxide, wherein the water-absorbing polymer particles have been coated, before, during or after the surface postcrosslinking with aluminum cations.
Claims8
A process for producing water-absorbing polymer particles by polymerizing an aqueous monomer solution or suspension comprising
- a) at least one ethylenically unsaturated monomer which bears an acid group, which has been neutralized to an extent of 70 to 85 mol %,
- b) at least one crosslinker,
- c) at least one initiator,
- d) optionally one or more ethylenically unsaturated monomer copolymerizable with the monomer specified under a), and
- e) optionally one or more water-soluble polymer, comprising drying a resulting aqueous polymer gel, grinding, classifying and thermal surface postcrosslinking to provide water-absorbing polymer particles, which comprises coating the water-absorbing polymer particles, before, during, or after the surface postcrosslinking, with 0.0001 to 0.25% by weight of silicon dioxide and at least 1.5×10−6 mol/g of aluminum cations.
2 more elements
Dependencies are inferred from the claim text.