	US 12,403,448 B2
	Permeable superabsorbent and process for production thereof
Christophe Bauduin, Ludwigshafen (DE)
Assigned to BASF SE, Ludwigshafen (DE)
Appl. No. 17/624,873
Filed by BASF SE, Ludwigshafen (DE)
PCT Filed Jul. 14, 2020, PCT No. PCT/EP2020/069893 § 371(c)(1), (2) Date Jan. 5, 2022, PCT Pub. No. WO2021/013639, PCT Pub. Date Jan. 28, 2021.
Claims priority of application No. 19188064 (EP), filed on Jul. 24, 2019.
Prior Publication US 2022/0288559 A1, Sep. 15, 2022
Int. Cl. B01J 20/26 (2006.01); B01J 20/30 (2006.01); C08F 220/06 (2006.01); C08F 222/10 (2006.01); C08J 3/24 (2006.01); C08K 3/22 (2006.01); C08L 33/02 (2006.01)

CPC B01J 20/261 (2013.01) [B01J 20/3021 (2013.01); B01J 20/3085 (2013.01); C08F 220/06 (2013.01); C08L 33/02 (2013.01)]

12 Claims

1. A process for producing a superabsorbent, comprising

polymerizing an aqueous monomer solution comprising:

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

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,

adding x-ray-amorphous aluminum hydroxide powder after drying, and

adding 0.1% to 10% by weight, based on the amount of polymer prior to the addition of the x-ray-amorphous aluminum hydroxide powder, of water after the addition of x-ray-amorphous aluminum hydroxide powder to produce the superabsorbent,

wherein the water is added to the polymer in at least three portions such that the gel bed permeability of the superabsorbent obtained is greater than the gel bed permeability of the same superabsorbent obtained by adding the water to the polymer all at once or in two portions.