US 12,030,967 B2
Preparation method of super absorbent polymer
Tae Young Won, Daejeon (KR); Jungmin Sohn, Daejeon (KR); Hyemin Lee, Daejeon (KR); Junwye Lee, Daejeon (KR); Seongbeom Heo, Daejeon (KR); Kwangin Shin, Daejeon (KR); and Chang Hun Han, Daejeon (KR)
Assigned to LG Chem, Ltd., Seoul (KR)
Appl. No. 17/057,790
Filed by LG Chem, Ltd., Seoul (KR)
PCT Filed Oct. 1, 2019, PCT No. PCT/KR2019/012832
§ 371(c)(1), (2) Date Nov. 23, 2020,
PCT Pub. No. WO2020/116760, PCT Pub. Date Jun. 11, 2020.
Claims priority of application No. 10-2018-0157082 (KR), filed on Dec. 7, 2018.
Prior Publication US 2021/0230316 A1, Jul. 29, 2021
Int. Cl. C08F 2/44 (2006.01); B01J 20/26 (2006.01); B01J 20/30 (2006.01); C08F 2/01 (2006.01); C08F 220/06 (2006.01); C08J 3/24 (2006.01); C08J 9/08 (2006.01); C08J 9/36 (2006.01)
CPC C08F 2/44 (2013.01) [B01J 20/267 (2013.01); B01J 20/3064 (2013.01); C08F 2/01 (2013.01); C08F 220/06 (2013.01); C08J 3/245 (2013.01); C08J 9/08 (2013.01); C08J 9/36 (2013.01); B01J 2220/68 (2013.01); C08J 2201/026 (2013.01); C08J 2333/08 (2013.01)] 15 Claims
 
1. A preparation method of a super absorbent polymer, comprising:
preparing a monomer mixture comprising a water-soluble ethylene-based unsaturated monomer having at least partially neutralized acidic groups and an internal cross-linking agent;
transferring the monomer mixture to a polymerization reactor;
during the transferring the monomer mixture to the polymerization reactor, adjusting a dynamic pressure applied to the monomer mixture being transferred calculated by the following Equation 1 to 0.140 kPa or more by controlling a transfer rate;
cross-linking and polymerizing the monomer mixture transferred to the polymerization reactor to form a hydrogel polymer;
drying, pulverizing and classifying the hydrogel polymer to form a base resin powder; and
further cross-linking a surface of the base resin powder in the presence of a surface cross-linking agent to form a surface cross-linked layer:
Dynamic pressure=½*p*V2  [Equation 1]
in Equation 1, p denotes a density (g/cm3) of the monomer mixture being transferred, and V denotes a transfer rate (m/s) of the monomer mixture.