Nanoporous superabsorbent particles

Patent metadata

Field	Value
Publication number	US-11596924-B2
Application number	US-201817252764-A
Country	US
Kind code	B2
Filing date	Jun 27, 2018
Priority date	Jun 27, 2018
Publication date	Mar 7, 2023
Grant date	Mar 7, 2023

Abstract

Superabsorbent particles have a median size of from about 50 to about 2,000 micrometers and contain a porous network that includes a plurality of nanopores having an average cross-sectional dimension of from about 10 to about 500 nanometers, wherein the superabsorbent particles exhibit a Vortex Time of about 80 seconds or less and a free swell gel bed permeability (GBP) of 5 darcys or more, of 10 darcys or more, of 20 darcys or more, of 30 darcys or more, of 60 darcys or more, or of 90 darcys or more. A method for forming such superabsorbent particles includes forming a composition that contains a superabsorbent polymer and a solvent system; contacting the composition with a non-solvent system to initiate formation of the porous network through phase inversion; removing non-solvent from the composition; and surface crosslinking the superabsorbent particles.

First claim

What is claimed is:

1. Superabsorbent particles having a median size of from 50 to 2,000 micrometers and containing a porous network that includes a plurality of nanopores having an average cross-sectional dimension of from 10 to 500 nanometers, wherein the superabsorbent particles exhibit a Vortex Time of 80 seconds or less and a free swell gel bed permeability (GBP) of 5 darcys or more.

2. The superabsorbent particles of claim 1 , wherein the particles exhibit a GBP of 10 darcys or more.

3. The superabsorbent particles of claim 1 , wherein the particles exhibit a GBP of 20 darcys or more.

4. The superabsorbent particles of claim 1 , wherein the particles exhibit a GBP of 60 darcys or more.

5. The superabsorbent particles of claim 1 , wherein the particles exhibit a GBP of 90 darcys or more.

6. The superabsorbent particles of claim 1 , wherein the particles exhibit an Absorption Rate of 300 g/g/ks or more after being placed into contact with an aqueous solution of 0.9 wt. % sodium chloride for 0.015 kiloseconds.

7. The superabsorbent particles of claim 1 , wherein the superabsorbent particles exhibit an Absorption Rate of 500 g/g/ks or more after being placed into contact with an aqueous solution of 0.9 wt. % sodium chloride for 0.015 kiloseconds.

8. The superabsorbent particles of claim 1 , wherein the superabsorbent particles exhibit an Absorption Rate of 160 g/g/ks or more after being placed into contact with an aqueous solution of 0.9 wt. % sodium chloride for 0.120 kiloseconds.

9. The superabsorbent particles of claim 1 , wherein the particles exhibit a Centrifuge Retention Capacity of 20 g/g or more.

10. The superabsorbent particles of claim 1 , wherein the porous network further comprises micropores.

11. The superabsorbent particles of claim 1 , wherein at least 25 vol. % of the porous network is formed by the nanopores.

12. The superabsorbent particles of claim 1 , wherein the particles are formed from a crosslinked polymer that contains repeating units derived from one or more ethylenically unsaturated monomeric compounds having at least one hydrophilic radical.

13. The superabsorbent particles of claim 12 , wherein the monomeric compounds are monoethylenically unsaturated.

14. The superabsorbent particles of claim 1 , wherein the particles exhibit a total pore area of 2 square meters per gram or more.

15. The superabsorbent particles of claim 1 , wherein the particles exhibit a percent porosity of 5% or more.

16. A method for forming the superabsorbent particles of claim 1 , the method comprising:
forming a composition that contains a superabsorbent polymer and a solvent system;
contacting the composition with a non-solvent system to initiate formation of the porous network through phase inversion;
removing non-solvent from the composition; and
surface crosslinking the superabsorbent particles.

17. The method of claim 16 , wherein the composition is a single-phase homogeneous composition.

18. The method of claim 16 , wherein contact with the non-solvent system forms a two-phase mixture.

19. The method of claim 16 , wherein the difference in the Hildebrand solubility parameter of the solvent system and the Hildebrand solubility parameter of the non-solvent system is from 1 to 15 calories 1/2 /cm 3/2 .

20. The method of claim 16 , wherein the solvent system includes water, aqueous alcohol, saline, glycerol, or a combination thereof.

Assignees

• Kimberly Clark Co

Inventors

• Topolkaraev Vasily A
• Pickett Austin N
• Goeders Karen
• Mleziva Mark M
• Tower Theodore T
• Lee Wanduk
• Scholl Neil T
• Eslinger Lori A
• Galabura Yuriy
• Soerens Dave
• Takahashi Kazuhiro
• Ueda Yusuke
• TOMIOKA Megumi

Classifications

• A61L2400/12

  Nanosized materials, e.g. nanofibres, nanoparticles, nanowires, nanotubes; Nanostructured surfaces · CPC title

• A61F13/53 Primary

  characterised by the absorbing medium (A61F13/20 takes precedence) · CPC title

• A61L15/60 Primary

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

• A61F2013/530569

  characterized by the particle size · CPC title

• A61F2013/530788

  characterized by the gel layer permeability · CPC title