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US 2026/0208155 A1Published application
Method for producing superabsorbents
AssigneeBASF SE
InventorsMonte Alan PETERSON, Vernon Lynn ADEY, Jan Niclas GORGES, Juergen SCHROEDER
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Abstract
The present invention relates to a process for continuously producing superabsorbents, where an aqueous monomer solution is polymerized to a polymer gel, the acrylic acid present in the offgas from the polymerization and/or drying is scrubbed out by means of an aqueous solution, the pH of the aqueous solution is from 9.0 to 12.5 and the acrylic acid-laden aqueous solution is used at least partly for production of the monomer solution or metered into the polymerization in parallel with the monomer solution.
Claims14
A process for continuously producing superabsorbents, comprising:
- polymerizing an aqueous monomer solution comprising a partly neutralized acrylic acid to a polymer gel;
- optionally extruding the polymer gel;
- drying the polymer gel;
- and
- comminuting, classifying, and optionally thermally surface postcrosslinking the dried polymer gel;
- wherein:
- a water content of the aqueous monomer solution is 40% to 75% by weight;
- the acrylic acid has been neutralized to an extent of 40 to 85 mol %;
- acrylic acid present in an offgas from the polymerization and/or drying is scrubbed out with an aqueous solution;
- a pH of the aqueous solution is from 9.0 to 12.5;
- and
- the acrylic acid-laden aqueous solution is used at least partly for production of the monomer solution or metered into the polymerization in parallel with the monomer solution.
9 more elements
Dependencies are inferred from the claim text.