US 12,435,191 B2
Super absorbent polymer and method for preparing same
Junwye Lee, Daejeon (KR); Chang Hun Lee, Daejeon (KR); Kwangin Shin, Daejeon (KR); Chang Hun Han, Daejeon (KR); and Sang Gi Lee, Daejeon (KR)
Assigned to LG Chem, Ltd., Seoul (KR)
Appl. No. 16/962,947
Filed by LG Chem, Ltd., Seoul (KR)
PCT Filed Dec. 6, 2018, PCT No. PCT/KR2018/015429
§ 371(c)(1), (2) Date Jul. 17, 2020,
PCT Pub. No. WO2019/143020, PCT Pub. Date Jul. 25, 2019.
Claims priority of application No. 10-2018-0007384 (KR), filed on Jan. 19, 2018.
Prior Publication US 2021/0179790 A1, Jun. 17, 2021
Int. Cl. C08F 20/06 (2006.01); C08J 3/075 (2006.01); C08J 3/12 (2006.01); C08J 3/14 (2006.01); C08J 3/24 (2006.01)
CPC C08J 3/245 (2013.01) [C08F 20/06 (2013.01); C08J 3/075 (2013.01); C08J 2205/022 (2013.01); C08J 2333/08 (2013.01); C08J 2333/10 (2013.01)] 7 Claims
 
1. A method for preparing super absorbent polymer particles, comprising:
A) performing crosslinking polymerization of a water-soluble ethylenically unsaturated monomer having an acidic group of which at least a part is neutralized, in the presence of a polymerization initiator and an internal crosslinking agent to form a hydrogel polymer;
B) forming a base polymer powder by drying, pulverizing, and size-sorting the hydrogel polymer;
C) forming super absorbent polymer particles by surface-crosslinking the base polymer powder through heat treatment in the presence of a surface crosslinking agent; and
D) performing a wetting step for 1 to 5 minutes after surface-crosslinking for adjusting water content of the super absorbent polymer particles through the wetting step after surface-crosslinking
by exposing all the super absorbent polymer particles obtained in Step C under conditions of a relative humidity of 50 RH % or more and less than 80 RH % and a temperature of 60° C. or more and less than 75° C., to produce
the super absorbent polymer particles with a water content of 0.1% to 5% by weight; and
a particle size of a particle size of 150 μm to 850 μm;
and a content of aggregates 1% by weight or less having a particle size of 850 μm or more.