Preparation method of superabsorbent polymer and superabsorbent polymer prepared thereby

Patent metadata

Field	Value
Publication number	US-10208171-B2
Application number	US-201815984977-A
Country	US
Kind code	B2
Filing date	May 21, 2018
Priority date	Jun 13, 2014
Publication date	Feb 19, 2019
Grant date	Feb 19, 2019

Abstract

Provided are a preparation method of a superabsorbent polymer, and a superabsorbent polymer prepared thereby. The preparation method of the superabsorbent polymer according to the present disclosure enables preparation of the superabsorbent polymer which is excellent in absorption properties such as centrifuge retention capacity and absorbency under pressure, and also has improved permeability. In addition, the preparation method exhibits excellent operability during the preparation (in particular, surface crosslinking of the polymer) and excellent productivity due to low production of coarse particles and fine particles.

First claim

The invention claimed is:

1. A superabsorbent polymer comprising a crosslinked polymer formed by polymerization and internal crosslinking of water-soluble ethylene-based unsaturated monomers and a polycarboxylic acid-based copolymer having repeating units represented by the following Chemical Formula 1-a and Chemical Formula 1-b, which is present on the crosslinked polymer:

wherein, in Chemical Formula 1-a and 1-b,
R 1 , R 2 , and R 3 are each independently hydrogen or an alkyl group having 1 to 6 carbon atoms,
RO is an oxyalkylene group having 2 to 4 carbon atoms,
M 1 is hydrogen or a monovalent metal or non-metal ion,
X is —COO—, an alkyloxy group having 1 to 5 carbon atoms, or an alkyldioxy group having 1 to 5 carbon atoms,
m is an integer of 1 to 100,
n is an integer of 1 to 1000, and
p is an integer of 1 to 150, and provided that there are two or more of p, two or more repeating (—RO—)s may be the same as or different from each other,
wherein the superabsorbent polymer has liquid permeability (SFC) of 60×10 −7 cm 3 *s/g to 130×10 −7 cm 3 *s/g, centrifuge retention capacity (CRC) of 27 g/g to 35 g/g, absorbency under pressure (AUP) of 23 g/g to 27 g/g, and permeability dependent absorption under pressure (PDAUP) of 20 g/g to 25 g/g.

2. The superabsorbent polymer of claim 1 , wherein the polycarboxylic acid-based copolymer has a weight average molecular weight of 500 to 1,000,000 g/mol.

3. The superabsorbent polymer of claim 1 , wherein the polycarboxylic acid-based copolymer is a random copolymer derived from methoxy polyethylene glycol monomethacrylate and (meth)acrylic acid.

4. The superabsorbent polymer of claim 1 , comprising a crosslinked polymer formed by polymerization and internal crosslinking of water-soluble ethylene-based unsaturated monomers to form a water-containing gel polymer, drying the water-containing gel polymer, pulverizing the dried water-containing gel polymer, and performing a surface crosslinking reaction by mixing the pulverized polymer with a surface crosslinking solution comprising a polycarboxylic acid-based copolymer having repeating units represented by the following Chemical Formula 1-a and Chemical Formula 1-b, which is present on the crosslinked polymer:

wherein, in Chemical Formula 1-a and 1-b,
R 1 , R 2 , and R 3 are each independently hydrogen or an alkyl group having 1 to 6 carbon atoms,
RO is an oxyalkylene group having 2 to 4 carbon atoms,
M 1 is hydrogen or a monovalent metal or non-metal ion,
X is —COO—, an alkyloxy group having 1 to 5 carbon atoms, or an alkyldioxy group having 1 to 5 carbon atoms,
m is an integer of 1 to 100,
n is an integer of 1 to 1000, and
p is an integer of 1 to 150, and provided that there are two or more of p, two or more repeating (—RO—)s may be the same as or different from each other.

5. The superabsorbent polymer of claim 4 , wherein the polycarboxylic acid-based copolymer is present in an amount of 0.001 to 5% by weight, based on 100 parts by weight of the pulverized polymer.

Assignees

• Lg Chemical Ltd

Inventors

• Lee Yong Hun
• Han Chang Sun
• Nam Hye Mi
• Ryu Dong Jo
• Lee Hyemin

Classifications

• A61L15/60

  Liquid-swellable gel-forming materials, e.g. super-absorbents · CPC title

• C08J3/245 Primary

  Differential crosslinking of one polymer with one crosslinking type, e.g. surface crosslinking · CPC title

• C08F2/10

  Aqueous solvent · CPC title

• C08J3/247

  Heating methods · CPC title

• C08J3/24

  Crosslinking, e.g. vulcanising, of macromolecules (mechanical aspects B29C35/00; crosslinking agents C08K) · CPC title