	US 12,084,527 B2
	Method for producing super absorber particles
Thomas Pfeiffer, Ludwigshafen (DE); Matthias Weismantel, Ludwigshafen (DE); Jürgen Schröder, Ludwigshafen (DE); Karl Possemiers, Antwerp (BE); Marco Krueger, Ludwigshafen (DE); and Ruediger Funk, Ludwigshafen (DE)
Assigned to BASF SE, Ludwigshafen (DE)
Appl. No. 16/968,192
Filed by BASF SE, Ludwigshafen (DE)
PCT Filed Feb. 11, 2019, PCT No. PCT/EP2019/053280 § 371(c)(1), (2) Date Aug. 7, 2020, PCT Pub. No. WO2019/162123, PCT Pub. Date Aug. 29, 2019.
Claims priority of application No. 18158090 (EP), filed on Feb. 22, 2018.
Prior Publication US 2020/0392258 A1, Dec. 17, 2020
Int. Cl. A61L 15/60 (2006.01); C08F 2/10 (2006.01); C08F 2/18 (2006.01); C08F 6/00 (2006.01); C08J 3/12 (2006.01); C08J 3/24 (2006.01)

CPC C08F 2/18 (2013.01) [A61L 15/60 (2013.01); C08F 2/10 (2013.01); C08F 6/008 (2013.01); C08J 3/12 (2013.01); C08J 3/245 (2013.01); C08J 2300/14 (2013.01); C08J 2333/02 (2013.01)]

19 Claims

1. A process for producing superabsorbent particles by polymerizing a monomer solution or suspension comprising

a) at least one ethylenically unsaturated monomer which bears an acid group and optionally is at least partly neutralized,

b) at least one crosslinker,

c) at least one initiator,

d) optionally one or more ethylenically unsaturated monomer copolymerizable with the monomer mentioned under a), and

e) optionally one or more water-soluble polymer,

to provide a polymer gel comprising

i) drying the polymer gel to produce a dried polymer gel,

ii) classifying the dried polymer gel from step i) to obtain at least one fraction of incompletely dried polymer particles and at least one fraction of dried polymer particles, and

iii) comminuting the incompletely dried polymer particles from step ii),

which comprises recycling the comminuted polymer particles from step iii) into the dried polymer gel before step ii) or into the dried polymer particles after step ii) and iv) storing together in a vessel for a period of at least 5 minutes,

wherein the vessel used for storage is thermally insulated and/or trace heated.