Preparation method of super absorbent polymer

Patent metadata

Field	Value
Publication number	US-10086362-B2
Application number	US-201615540705-A
Country	US
Kind code	B2
Filing date	Nov 1, 2016
Priority date	Nov 3, 2015
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

The present invention relates to a manufacturing method of a super absorbent polymer including: carrying out a thermal polymerization or a photopolymerization of a monomer composition including a water-soluble ethylene-based unsaturated monomer and a polymerization initiator to form a hydrogel polymer; drying the hydrogel polymer; pulverizing the dried polymer; classifying the pulverized polymer into a fine powder having a particle diameter of less than 150 μm and a polymer having a particle diameter of 150 to 850 μm according to the particle diameter; performing reassembly to form a fine powder reassembly; and mixing the polymer having a particle diameter of 150 to 850 μm with the fine powder reassembly, followed by surface cross-linking.

First claim

What is claimed is:

1. A method for preparing a super absorbent polymer comprising the steps of:
carrying out a thermal polymerization or a photopolymerization of a monomer composition comprising a water-soluble ethylene-based unsaturated monomer and a polymerization initiator to form a hydrogel polymer;
drying the hydrogel polymer to form a dried polymer;
pulverizing the dried polymer to form a pulverized polymer;
classifying the pulverized polymer into a fine powder having a particle diameter of less than 150 μm and a polymer having a particle diameter of 150 to 850 μm according to the particle diameter;
performing reassembly by mixing and wetting the fine powder with 5 to 30° C. water in a content of 50 to 200 parts by weight with respect to 100 parts by weight of the fine powder having a particle size of 150 μm or less, to form a fine powder reassembly; and
mixing the polymer having a particle diameter of 150 to 850 μm with the fine powder reassembly, followed by surface cross-linking,
wherein the polymer having a particle diameter of 150 to 850 μm and the fine powder reassembly are mixed at a weight ratio of 7:3 to 8:2.

2. The manufacturing method of claim 1 , wherein in the surface cross-linking, a surface cross-linking agent is used in a content of 0.001 to 5 parts by weight with respect to 100 parts by weight of the polymer having a particle diameter of 150 to 850 μm and the fine powder reassembly.

3. The manufacturing method of claim 2 , wherein the surface cross-linking agent comprises at least one selected from the group consisting of a polyhydric alcohol compound; an epoxy compound; a polyamine compound; a haloepoxy compound; a condensation product of the haloepoxy compound; oxazoline compounds; mono-, di- or polyoxazolidinone compound; a cyclic urea compound; a polyvalent metal salt; and an alkylene carbonate compound.

4. The manufacturing method of claim 1 , wherein the surface cross-linking is performed at a temperature of 150° C. to 300° C. for 10 minutes to 100 minutes.

5. The manufacturing method of claim 1 , wherein the fine powder is mixed and wetted with the 5 to 30° C. water using a mist or a spray device.

6. The manufacturing method of claim 1 , wherein in the performing of the reassembly, the fine powder is reassembled in a state in which a moisture content is 40 to 60 wt %.

7. The manufacturing method of claim 1 , wherein a moisture content of the hydrogel polymer is 40 to 60 wt %.

8. The manufacturing method of claim 1 , wherein a moisture content of the dried polymer is 0.1 to 10 wt %.

Assignees

• Lg Chemical Ltd

Inventors

• Kim Dong Hyun
• Han Chang Sun
• Nam Dae Woo

Classifications

• B01J20/3085

  Chemical treatments not covered by groups B01J20/3007 - B01J20/3078 · CPC title

• C08J2333/00

  Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers · CPC title

• C08J3/075

  Macromolecular gels · CPC title

• C08F6/008

  Treatment of solid polymer wetted by water or organic solvents, e.g. coagulum, filter cakes · CPC title

• B01J20/28047

  Gels · CPC title