US 12,269,010 B2
Water-absorbing resin and water-blocking material
Maoki Hama, Himeji (JP)
Assigned to SUMITOMO SEIKA CHEMICALS CO., LTD., Hyogo (JP)
Appl. No. 17/599,071
Filed by SUMITOMO SEIKA CHEMICALS CO., LTD., Hyogo (JP)
PCT Filed Mar. 27, 2020, PCT No. PCT/JP2020/013899
§ 371(c)(1), (2) Date Sep. 28, 2021,
PCT Pub. No. WO2020/203722, PCT Pub. Date Oct. 8, 2020.
Claims priority of application No. 2019-069053 (JP), filed on Mar. 29, 2019.
Prior Publication US 2022/0176347 A1, Jun. 9, 2022
Int. Cl. B01J 20/26 (2006.01); B01J 20/28 (2006.01)
CPC B01J 20/267 (2013.01) [B01J 20/28016 (2013.01); B01J 2220/44 (2013.01)] 3 Claims
 
1. A water-absorbent resin comprising a crosslinked polymer of a water-soluble ethylenically unsaturated monomer and a chelating agent having five or more ligands,
the water-absorbent resin having a median particle size of 100 to 200 μm,
the water-absorbent resin having a gel viscosity retention S of 0.5 or more as calculated by the following formula (I):

OG Complex Work Unit Math
wherein A represents an initial gel viscosity (mPa·s); and
B represents a gel viscosity (mPa·s) after 10 days, and
the initial gel viscosity A of the water-absorbent resin being 4000 mPa's or more and being measured by the following method: 1500 g of distilled water is added to a beaker, and stirred at 600 rpm using a magnetic stirrer bar; 1.5 g of a water absorbent resin is placed into a vortex created by this stirring and the mixture is stirred for 1 hour; the resulting mixture is then filtered through a 200 mesh wire mesh, and allowed to stand for 15 minutes; the gel viscosity of the thus-obtained swollen gel is immediately measured and used as the initial gel viscosity.