Superabsorbent polymer and method for preparing the same

Patent metadata

Field	Value
Publication number	US-11192088-B2
Application number	US-201615557607-A
Country	US
Kind code	B2
Filing date	Apr 14, 2016
Priority date	Dec 23, 2015
Publication date	Dec 7, 2021
Grant date	Dec 7, 2021

Abstract

The present invention relates to superabsorbent polymer having an improved absorption speed through micropores formed inside, and a method for preparing the same.

First claim

What is claimed is:

1. A superabsorbent polymer, comprising:
a base resin powder comprising a crosslinked homopolymer of acrylic acid monomers having acid groups of which at least a part are neutralized,
wherein a plurality of pores with a diameter of 1 μm or more are formed in the base resin powder,
wherein the crosslinked homopolymer comprises layered silicate-based particles dispersed in a crosslinking structure,
wherein the layered silicate-based particles comprise hectorite,
wherein the superabsorbent polymer has a time for removing vortex generated of 60 seconds or less when stirring 2 grams of the superabsorbent polymer at 600 rpm in 50 ml of a 0.9 wt % NaCl solution, and
wherein a centrifuge retention capacity for a saline solution, measured according to EDANA method WSP 241.2, is 45 g/g or more.

2. The superabsorbent polymer according to claim 1 , wherein the plurality of pores with a diameter of 1 μm or more formed in the base resin powder comprise micropores with diameters of 10 μm to 100 μm.

3. The superabsorbent polymer according to claim 1 , wherein the layered silicate-based particles comprise a unit crystal comprising a metal oxide layer, and a silica layer comprising silica formed on at least one side of the metal oxide layer.

4. The superabsorbent polymer according to claim 1 , wherein the layered silicate-based particles have a column structure with a maximum diameter of a cross section of 1 nm to 100 nm, and a height of 0.1 nm to 20 nm.

5. The superabsorbent polymer according to claim 1 , wherein the layered silicate-based particles are included in the content of 0.01 parts by weight to 5 parts by weight, based on 100 parts by weight of the base resin powder.

6. The superabsorbent polymer according to claim 1 , wherein the crosslinked homopolymer comprises a crosslinking structure in which polymer chains of the acrylic acid monomers are crosslinked through crosslinkable functional groups of an internal crosslinking agent.

7. The superabsorbent polymer according to claim 1 , wherein the crosslinked homopolymer comprises a crosslinked homopolymer formed by polymerization of the acrylic acid monomers in the presence of an internal crosslinking agent comprising a multifunctional acrylate-based compound.

8. The superabsorbent polymer according to claim 6 , wherein the internal crosslinking agent comprises one or more selected from the group consisting of polyethyleneglycol diacrylate(PEGDA), glycerin diacrylate glycerin triacrylate, non-modified or ethoxylated trimethylol propane triacrylate(TMPTA), hexanedioldiacrylate, and triethyleneglycol diacrylate.

9. A method for preparing a superabsorbent polymer comprising steps of:
conducting a crosslinking polymerization of acrylic acid monomers having acid groups of which at least a part are neutralized, in the presence of layered silicate-based particles comprised hectorite, a blowing agent and an internal crosslinking agent, to form a hydrogel polymer; and
drying, grinding and sieving the hydrogel polymer to form a base resin powder, wherein the superabsorbent polymer comprises:

the base resin powder comprising a crosslinked homopolymer of the acrylic acid monomers having acid groups of which at least a part are neutralized,
wherein a plurality of pores with a diameter of 1 μm or more are formed in the base resin powder,
wherein the crosslinked homopolymer comprises the layered silicate-based particles dispersed in a crosslinking structure,
wherein the superabsorbent polymer has a time for removing vortex generated of 60 seconds or less when stirring 2 grams of the superabsorbent polymer at 600 rpm in 50 ml of a 0.9 wt % NaCl solution, and
wherein a centrifuge retention capacity for a saline solution, measured according to EDANA method WSP 241.2, is 45 g/g or more.

10. The method for preparing superabsorbent polymer according to claim 9 , wherein, in the step of forming the hydrogel polymer, based on 100 parts by weight of the blowing agent, 1 to 1000 parts by weight of the layered silicate-based particles are used.

11. The method for preparing superabsorbent polymer according to claim 9 , wherein the step of forming hydrogel polymer comprises steps of
forming a first solution comprising the internal crosslinking agent, and the acrylic acid monomers having acid groups of which at least a part are neutralized;
forming a second solution comprising the layered silicate-based particles and the blowing agent; and
progressing the crosslinking polymerization of a monomer composition comprising the first solution and the second solution.

12. The method for preparing superabsorbent polymer according to claim 11 , wherein, in the step of forming the first solution comprising the internal crosslinking agent, and the acrylic acid monomers having acid groups of which at least a part are neutralized, the content of the internal crosslinking agent is 0.01 parts by weight to 5 parts by weight, based on 100 parts by weight of the acrylic acid monomers.

13. The method for preparing superabsorbent polymer according to claim 11 , wherein, in the step of crosslinking polymerization of a monomer composition comprising the first solution and the second solution, the content of the second solution is 1 part by weight to 100 parts by weight, based on 100 parts by weight of the first solution included in the monomer composition.

14. The superabsorbent polymer according to claim 7 , wherein the internal crosslinking agent comprises one or more selected from the group consisting of polyethyleneglycol diacrylate(PEGDA), glycerin diacrylate glycerin triacrylate, non-modified or ethoxylated trimethylol propane triacrylate(TMPTA), hexanedioldiacrylate, and triethyleneglycol diacrylate.

Assignees

• Lg Chemical Ltd

Inventors

• Lee Kum Hyoung
• Kim Gi Cheul
• Park Sung Soo
• Yang Ye Sol

Classifications

• C08K2201/003

  Additives being defined by their diameter · CPC title

• C08F20/06

  Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof · CPC title

• C08F220/385

  and containing nitrogen · CPC title

• C08K7/26

  Silicon- containing compounds · CPC title

• C08K3/34

  Silicon-containing compounds · CPC title