Super absorbent polymer and preparation method thereof

Patent metadata

Field	Value
Publication number	US-10889673-B2
Application number	US-201816158582-A
Country	US
Kind code	B2
Filing date	Oct 12, 2018
Priority date	May 13, 2013
Publication date	Jan 12, 2021
Grant date	Jan 12, 2021

Abstract

The present invention relates to a super absorbent polymer and a preparation method thereof, the super absorbent polymer including: surface cross-linked polymer particles prepared by surface cross-linking particles of a base resin, the base resin polymerized from a monomer composition including water-soluble ethylene-based unsaturated monomers having at least partially neutralized acidic groups; and a water-soluble component, wherein the water-soluble component has a weight average molecular weight of 150,000 to 300,000 g/mol. The super absorbent polymer may have high centrifuge retention capacity and excellent permeability at the same time, while having low content of the water-soluble component.

First claim

What is claimed is:

1. A preparation method of a super absorbent polymer, comprising:
preparing a monomer composition including a water-soluble ethylene-based unsaturated monomers have un-neutralized acidic groups, and a polymerization initiator, wherein the polymerization initiator has a content of 40 to 300 ppm based on the amount of water-soluble ethylene-based unsaturated monomers;
adding a neutralizing agent to the monomer composition to neutralize at least some of the un-neutralized acidic groups of the water-soluble ethylene-based unsaturated monomers;
preparing a hydrogel polymer by polymerizing the monomer composition, wherein a polymerization temperature ranges from 20 to 45° C.;
drying the hydrogel polymer;
pulverizing the dried polymer to form particles; and
surface cross-linking the particles in the presence of a surface cross-linking agent to form surface cross-linked polymer particles of the super absorbent polymer, wherein the surface cross-linking agent is present in an amount ranging from 0.15 to 0.7 wt % based on an amount of the particles.

2. The preparation method of claim 1 , wherein the super absorbent polymer includes a water-soluble component included in the super absorbent polymer has a weight average molecular weight of 150,000 to 300,000.

3. The preparation method of claim 1 , wherein the surface crosslinking is performed at temperatures ranging from about 120 to about 185 degrees Celsius.

4. The preparation method of claim 1 , wherein preparing the monomer composition further comprises:
adding an internal cross linking agent.

5. The preparation method of claim 1 , wherein the surface cross-linking agent includes aluminum sulfate.

6. The preparation method of claim 1 , wherein the super absorbent polymer comprising:
surface cross-linked polymer particles prepared by surface cross-linking particles of a base resin, the base resin polymerized from a monomer composition including water-soluble ethylene-based unsaturated monomers having at least partially neutralized acidic groups; and
a water-soluble component,
wherein the water-soluble component has a weight average molecular weight of 150,000 to 250,000 g/mol,
wherein the water-soluble component has a content of 5 to 20 wt %, based on the total weight of the super absorbent polymer, as measured by the EDANA WSP 270.2 method; and
wherein a permeability of the super absorbent polymer measured according to the following Equation 1 is 10 to 150 seconds:
Permeability (sec)= T 1 −B   [Equation 1]

wherein T 1 represents a time required for decreasing a liquid level height from 40 ml up to 20 ml under a load of 0.3 psi (106.26 g) in a chromatography tube in the presence of saline solution-absorbed super absorbent polymer, wherein the saline solution-absorbed super absorbed polymer is prepared by putting 0.2±0.0005 g of a classified sample (30 # to 50 #) (particles size ranging from 300 μm to 600 μm) of super absorbent polymer into the chromatography tube and adding saline solution so that the saline solution has a volume of 50 ml, and leaving the tube for 30 minutes prior to measuring T 1 , and
B represents a time required for decreasing a liquid level height from 40 ml up to 20 ml in a chromatography tube filled with saline solution under a load of 0.3 psi in the absence of the super absorbent polymer;
wherein a centrifuge retention capacity is 30 to 35 g/g as measured by the EDANA WSP 241.2 method.

Assignees

• Lg Chemical Ltd

Inventors

• Lee Sang Gi
• Ryu Chul Hee
• Kim Kyu Pal
• Kim Bhom Ri

Classifications

• C08F222/102

  of dialcohols, e.g. ethylene glycol di(meth)acrylate or 1,4-butanediol dimethacrylate · CPC title

• C08L101/14

  the macromolecular compounds being water soluble or water swellable, e.g. aqueous gels · CPC title

• C08J2333/02

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

• C08J3/075 Primary

  Macromolecular gels · CPC title

• C08F20/10

  Esters · CPC title