US 11,680,142 B2
Process for producing superabsorbent polymer particles
Ruediger Funk, Luwigshafen (DE); Thomas Pfeiffer, Ludwigshafen (DE); Matthias Weismantel, Ludwigshafen (DE); Monte Alan Peterson, Freeport, TX (US); Karl Possemiers, Antwerp (BE); and Ronny De Kaey, Antwerp (BE)
Assigned to BASF SE, Ludwigshafen (DE)
Appl. No. 16/628,689
Filed by BASF SE, Ludwigshafen (DE)
PCT Filed Jul. 6, 2018, PCT No. PCT/EP2018/068326
§ 371(c)(1), (2) Date Jan. 6, 2020,
PCT Pub. No. WO2019/011793, PCT Pub. Date Jan. 17, 2019.
Claims priority of application No. 17180871 (EP), filed on Jul. 12, 2017.
Prior Publication US 2020/0216622 A1, Jul. 9, 2020
Int. Cl. C08J 3/12 (2006.01); B07B 1/46 (2006.01); C08J 3/075 (2006.01); C08J 3/24 (2006.01)
CPC C08J 3/12 (2013.01) [B07B 1/46 (2013.01); C08J 3/075 (2013.01); C08J 3/245 (2013.01); C08J 2300/12 (2013.01); C08J 2300/14 (2013.01); C08J 2333/08 (2013.01)] 21 Claims
 
1. A process for producing superabsorbent polymer particles, comprising polymerization of a monomer solution or suspension, comprising
a) at least one ethylenically unsaturated monomer which bears an acid group and may be 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,
drying a resulting polymer gel, grinding, classifying, and surface postcrosslinking the resulting polymer particles, wherein the surface postcrosslinked superabsorbent polymer particles are classified into an undersize, midsize, and oversize fraction, the superabsorbent polymer particles of the oversize fraction are deagglomerated using a roll crusher, and the deagglomerated superabsorbent polymer particles are recycled before or into the classification of the surface postcrosslinked superabsorbent polymer particles,
wherein the roll crusher is a double toothed roll crusher.