Superabsorbent surface-treated carboxyalkylated polysaccharides and process for producing same

• US 8,461,129 B2
• Filed: 09/25/2007
• Issued: 06/11/2013
• Est. Priority Date: 09/25/2006
• Status: Active Grant

• Current Assignee: Archer Daniels Midland Company
• Original Assignee: Archer Daniels Midland Company
• Inventors: Bolduc, Isabelle, Couffin, Anne-Claude, Dong, Shuojia, Godin, Danick, Koutlakis, George, Lachapelle, Nicole, Lavergne, Caroline, Nettel, Vladimiro, Nourry, Nicolas, Suarez-Hernandez, Oscar, Theriault, Catherine, Laforest, Andr, Picard, Frdric
• Primary Examiner(s): Shen, Wu-Cheng Winston
• Assistant Examiner(s): White, Everett
• Application Number:
  US11/861,081
• Publication Number:
  US 20080177057A1
• Time in Patent Office: 2,086 Days
• Field of Search: 536/97, 536/98, 536/104, 536/108, 536/116, 514/54, 127/49, 516/136
• US Class Current: 514/54
• CPC Class Codes: A61L 15/28 Polysaccharides or their derivatives A61L15/225 takes precedence
• CPC Class Codes: A61L 15/60 Liquid-swellable gel-forming materials, e.g. super-absorbents
• CPC Class Codes: C08B 11/12 substituted with carboxylic radicals , e.g. carboxymethylcellulose [CMC]
• CPC Class Codes: C08B 30/00 Preparation of starch, degraded or non-chemically modified starch, amylose, or amylopectin
• CPC Class Codes: C08B 31/12 having alkyl or cycloalkyl radicals substituted by heteroatoms, e.g. hydroxyalkyl or carboxyalkyl starch
• CPC Class Codes: C08B 37/00 Preparation of polysaccharides not provided for in groups C08B1/00 - C08B35/00; Derivatives thereof cellulose D21; microbiological processes C12P
• CPC Class Codes: C08J 2301/00 Characterised by the use of cellulose, modified cellulose or cellulose derivatives
• CPC Class Codes: C08J 2303/06 Esters
• CPC Class Codes: C08J 3/245 Differential crosslinking of one polymer with one crosslinking type, e.g. surface crosslinking
• CPC Class Codes: C08J 7/14 with acids, their salts or anhydrides
• CPC Class Codes: C08J 7/16 with polymerisable compounds

Abstract

Surface-treated carboxyalkylated polysaccharides comprising a biobased content of at least 82% are described herein. The surface-treated carboxyalkylated polysaccharides comprise a CRC of at least 18 g/g, a FSC of at least 26 g/g, and an AUL at 0.7 psi of at least 14 g/g. Processes for the manufacture of surface-treated carboxyalkylated polysaccharides are also described herein.

Claims

1. A superabsorbent material comprising:

a particle formed of a carboxyalkylated polysaccharide having a pH in a range from about 5.0 to about 10, said particle having an interior and a surface, each exhibiting a differentiated functionality;

said interior is absorbent;

said surface is treated with a non-crosslinking acid in the presence of an organic solvent, such that penetration depth of said non-crosslinking acid is limited to said surface, said non-crosslinking acid induces ester linkages between polysaccharide strands at said particle surface, which imparts said particle with a sufficient structural rigidity to enable said particle to maintain a discrete particle shape when contacted with a salt solution, and said superabsorbent material exhibits an absorption under load (AUL) at 0.7 psi of at least 14 g/g and a centrifuge retention capacity (CRC) of at least 18 g/g.

2. The superabsorbent material according to claim 1, wherein said carboxyalkylated polysaccharide particle exhibits a discrete gel particle shape when swollen to its maximum volume in saline solution.

3. The superabsorbent material according to claim 1, wherein said non-crosslinking agent includes HCl, acetic acid, glycolic acid, stearic acid, and other organic or inorganic monovalent acids.

4. The superabsorbent material according to claim 1, wherein said carboxyalkylated polysaccharide particle has a greater absorbance under load (AUL) of said salt solution at 0.7 psi than a comparative particle formed of the carboxyalkylated polysaccharide having a surface that is not treated with the non-crosslinking acid.

5. The superabsorbent material according to claim 1, wherein said carboxyalkylated polysaccharide particle exhibits at least one property selected from the group consisting of:

an AUL at 0.7 psi of at least 14 g/g, a centrifuge retention capacity (CRC) of at least 18 g/g, and a free swell capacity (FSC) of at least 26 g/g.

6. The superabsorbent material according to claim 1, wherein said carboxyalkylated polysaccharide exhibits the presence of an ester shoulder or ester band as determined by ATR-IR spectroscopy.

7. The superabsorbent material according to claim 1, wherein said carboxyalkylated polysaccharide particle has a size in a range from about 150 μ

m to about 850 μ

m.

8. The superabsorbent material according to claim 1, wherein said carboxyalkylated polysaccharide has a degree of substitution ranging from 0.2 to 1.0.

9. The superabsorbent material according to claim 1, wherein said carboxyalkylated polysaccharide has a homogeneous carboxyalkyl distribution pattern.

10. The superabsorbent material according to claim 1, wherein said carboxyalkylated polysaccharide particle is glass-like.

11. The superabsorbent material according to claim 1, wherein said carboxyalkylated polysaccharide has a biobased content of at least 82%.

12. The superabsorbent material according to claim 1, wherein said carboxyalkylated polysaccharide is a carboxymethyl starch.

13. The superabsorbent material according to claim 1, wherein said carboxyalkylated polysaccharide is internally crosslinked with ionic or ether linkages.

14. The superabsorbent material according to claim 1, wherein said salt solution is a 0.9% solution of NaCl.

15. A hygiene article comprising an absorbent member, said absorbent member has a content between about 15% to about 80% of a carboxyalkylated polysaccharide particle according to claim 1, said hygiene article exhibiting at least one property selected from the group consisting of:

a third acquisition rate of at least 0.22 ml/sec.;

a third rewet of at most 4.0 grams;

an averaged acquisition rate of at least 0.12 mi/sec., and a total rewet of at most 6.0 grams.

16. The hygiene article according to claim 15, wherein said absorbent member has carboxyalkylated polysaccharide particle content of between about 30% to about 60%.

17. The hygiene article according to claim 15, wherein said hygiene article is selected from the group consisting of diapers, incontinence articles, sanitary napkins, feminine hygiene products, and absorbent dressings.