Method for preparing super absorbent polymer

Patent metadata

Field	Value
Publication number	US-11613591-B2
Application number	US-202017286212-A
Country	US
Kind code	B2
Filing date	Aug 11, 2020
Priority date	Sep 18, 2019
Publication date	Mar 28, 2023
Grant date	Mar 28, 2023

Abstract

A method for preparing a super absorbent polymer and a superabsorbent polymer prepared from the same are disclosed herein. In some embodiments, a method includes mixing super absorbent polymer particles, water and an additive form a hydrated super absorbent polymer, wherein the super absorbent polymer particles comprise a base polymer powder including a cross-linked polymer polymerized from a water-soluble ethylenically unsaturated monomer having an acidic group of which at least a part is neutralized, and a surface cross-linked layer formed on the base polymer powder, wherein the surface cross-linked layer is formed by further cross-linking the cross-linked polymer, and wherein the additive including a polyoxyalkylene aliphatic hydrocarbon ether carboxylic acid. The method can appropriately control the water content of the super absorbent polymer by water-addition or the like to suppress crushing or the like during transfer, and also can suppress deterioration of physical properties.

First claim

The invention claimed is:

1. A method for preparing a super absorbent polymer, comprising
mixing super absorbent polymer particles, water and an additive form a hydrated super absorbent polymer,
wherein the super absorbent polymer particles comprise a base polymer powder including a cross-linked polymer polymerized from a water-soluble ethylenically unsaturated monomer having an acidic group of which at least a part is neutralized, and a surface cross-linked layer formed on the base polymer powder, wherein the surface cross-linked layer is formed by further cross-linking the cross-linked polymer, and
wherein the additive including a polyoxyalkylene aliphatic hydrocarbon ether carboxylic acid.

2. The method for preparing a super absorbent polymer according to claim 1 , wherein the additive includes polyoxyethylene aliphatic alkyl ether carboxylic acid having 1 to 20 repeat units.

3. The method for preparing a super absorbent polymer according to claim 2 , wherein the aliphatic alkyl bonded to the additive has a carbon number of 10 to 30.

4. The method for preparing a super absorbent polymer according to claim 1 , wherein the additive is mixed in an amount of 5 to 20,000 ppmw based on the weight of the super absorbent polymer particles.

5. The method for preparing a super absorbent polymer according to claim 1 , wherein the water is mixed in an amount of 1 to 10 parts by weight based on 100 parts by weight of the super absorbent polymer particles.

6. The method for preparing a super absorbent polymer according to claim 1 , wherein the mixing step is performed at a temperature of 40 to 80° C.

7. The method for preparing a super absorbent polymer according to claim 1 , further comprising:
drying and classifying the hydrated super absorbent polymer, wherein the dried and classified superabsorbent polymer has a particle size of 150 to 850 μm and a water content of 1 to 2.5% by weight.

8. The method for preparing a super absorbent polymer according to claim 7 , wherein particles having a particle size of more than 850 μm removed in the process of classification is less than 5% by weight based on the total weight of the dried super absorbent polymer.

9. The method for preparing a super absorbent polymer according to claim 7 , wherein the dried and classified superabsorbent polymer has a centrifuge retention capacity (CRC) of 30 to 45 g/g, wherein the CRC is measured using a physiological saline solution having 0.9 wt. % aqueous sodium chloride solution for 30 minutes.

10. The method for preparing a super absorbent polymer according to claim 7 , further comprising transferring the dried and classified superabsorbent polymer.

Assignees

• Lg Chemical Ltd

Inventors

• Kim Kyu Pal
• Chung Ui Seok
• Ahn Gyunhyeok
• Kim Gicheul

Classifications

• B01J20/28047

  Gels · CPC title

• C08K3/011

  Crosslinking or vulcanising agents, e.g. accelerators · CPC title

• C08F6/14

  Treatment of polymer emulsions {(C08F6/001, C08F6/006, C08F6/008, C08F6/02, C08F6/04 take precedence)} · CPC title

• C08J3/075

  Macromolecular gels · CPC title

• C08J2333/02

  Homopolymers or copolymers of acids; Metal or ammonium salts thereof · CPC title