Biodegradable Superabsorbent Particles

• US 20090325799A1
• Filed: 06/30/2008
• Published: 12/31/2009
• Est. Priority Date: 06/30/2008
• Status: Active Grant

• Current Assignee: International Paper Company
• Original Assignee: Weyerhaeuser Company (Weyerhauser)
• Inventors: Weerawarna, S Ananda
• Granted Patent: US 8,101,543 B2
• Time in Patent Office: Days
• US Class Current: 502/404
• CPC Class Codes: A61L 15/225 Mixtures of macromolecular compounds
• CPC Class Codes: A61L 15/60 Liquid-swellable gel-forming materials, e.g. super-absorbents
• CPC Class Codes: C08L 1/28 Alkyl ethers
• CPC Class Codes: C08L 3/02 Starch; Degradation products thereof, e.g. dextrin
• CPC Class Codes: Y10S 502/526 Sorbent for fluid storage, other than an alloy for hydrogen storage

Abstract

Particles comprising a combination of a carboxyalkyl cellulose and a starch, wherein the particles comprise a plurality of non-permanent metal crosslinks. The non-permanent intra-fiber metal crosslinks include multi-valent metal ion crosslinks formed with one or more metal ions selected from aluminum, boron, bismuth, titanium, and zirconium ions.

Claims

1. Particles comprising a combination of a carboxyalkyl cellulose and a starch, wherein the particles comprise a plurality of non-permanent metal crosslinks.

2. The particles of claim 1, wherein the carboxyalkyl cellulose has a degree of carboxyl group substitution of from about 0.3 to about 2.5.

3. The particles of claim 1, wherein the carboxyalkyl cellulose is carboxymethyl cellulose.

4. The particles of claim 1, wherein the starch is selected from the group consisting of corn, wheat, maize, rice, sorghum, potato, cassava, barley, buckwheat, millet, oat, arrowroot, beans, peas, rye, tapioca, sago, and amaranth starches.

5. The particles of claim 1, wherein the starch is present in an amount from about 1 to about 20 percent by weight based on the total weight of the particles.

6. The particles of claim 1, wherein the carboxyalkyl cellulose is present in an amount from about 60 to about 99 percent based on the total weight of particles.

7. The particles of claim 1, wherein the non-permanent metal crosslinks comprise multi-valent metal ion crosslinks.

8. The particles of claim 1, wherein the non-permanent metal crosslinks comprise one or more metal ions selected from the group consisting of aluminum, boron, bismuth, titanium, and zirconium, and mixtures thereof.

9. The particles of claim 1 having a free swell capacity of from about 30 to about 60 g/g for 0.9% saline solution.

10. The particles of claim 1 having a centrifuge retention capacity of from about 15 to about 40 g/g for 0.9% saline solution.

11. The particles of claim 1 having a size less than about 1500 μ

m.