US2004215160A1PendingUtilityA1

Superabsorbent polymers providing long-term generation of free volume in partially hydrated absorbent cores

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Individually held — no corporate assignee on recordPriority: Apr 10, 2001Filed: Jan 20, 2004Published: Oct 28, 2004
Est. expiryApr 10, 2021(expired)· nominal 20-yr term from priority
Inventors:Harry ChmielewskiAndrew T. Baker
A61F 13/53A61F 13/15658A61L 15/60A61F 13/531A61L 15/18A61F 2013/15463A61F 13/15699A61F 2013/530744A61F 2013/530481
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Claims

Abstract

An absorbent composition providing unexpectedly high fluid capacity with minimal gel-blocking, articles comprising the absorbent composition and methods of preparing the absorbent composition are disclosed. The absorbent composition optionally comprises a surface crosslinked polymer disbursed within a fibrous matrix of wettable fibers. The surface crosslinked polymer has an FVAUL value of at least about 60 cc after 10 minutes.

Claims

exact text as granted — not AI-modified
What is claimed is:  
     
         1 . A method for preparing an absorbent composition comprising: 
 providing a first layer of wettable fibers;    distributing on the first layer of wettable fibers a layer of surface crosslinked polymer having a FVAUL value of at least about 60 cc after 10 minutes;    providing a second layer of wettable fibers on top of the layer of surface crosslinked polymer; and    calendaring said layers to form the wettable fibers into a fibrous matrix having the surface crosslinked polymer disbursed therein, said surface crosslinked polymer comprising about 70% by weight to about 95% by weight the absorbent composition and said wettable fibers comprising about 5% by weight to about 30% by weight of the absorbent composition.    
     
     
         2 . The method of  claim 1 , wherein the surface crosslinked polymer is bipolar.  
     
     
         3 . The method of  claim 1 , wherein the surface crosslinked polymer provides minimal gel-blocking properties upon absorption of liquid.  
     
     
         4 . The method of  claim 1 , wherein the surface crosslinked polymer constitutes about 85% by weight to about 95% by weight of the combined weight of the fiberous matrix and the surface crosslinked polymer.  
     
     
         5 . The method of  claim 1 , wherein the surface crosslinked polymer constitutes about 90% by weight to about 95% by weight of the combined weight of the fiberous matrix and the surface crosslinked polymer.  
     
     
         6 . The method of  claim 1 , wherein said wettable fibers constitute about 5% by weight to about 15% by weight of the combined weight of the fiberous matrix and the surface crosslinked polymer.  
     
     
         7 . The method of  claim 1 , wherein said wettable fibers constitute about 5% by weight to about 10% by weight of the combined weight of the fiberous matrix and the surface crosslinked polymer.  
     
     
         8 . The method of  claim 1 , wherein the surface crosslinked polymer comprises a mixed-bed ion-exchange superabsorbent polymer composition.  
     
     
         9 . The method of  claim 1 , wherein the surface crosslinked polymer continues to swell at a substantially constant rate for at least about 0.4 hours after a third dose of urine at a finite volume of urine absorption.  
     
     
         10 . The method of  claim 1 , wherein the surface crosslinked polymer achieves equilibrium swelling levels within about 5 minutes to about 10 minutes after a third dose of urine.  
     
     
         11 . The method of  claim 1 , wherein the surface crosslinked polymer achieves equilibrium swelling levels at an FVAUL value of no less than about 75 cc.  
     
     
         12 . The method of  claim 1 , wherein the FVAUL free volume of the absorbent composition is about 20% to about 70%.  
     
     
         13 . The method of  claim 1 , wherein the FVAUL free volume of the absorbent composition is about 20% to about 60%.  
     
     
         14 . The method of  claim 1 , wherein the FVAUL free volume of the absorbent composition is about 20% to about 50%.  
     
     
         15 . The method of  claim 1 , wherein the FVAUL free volume of the absorbent composition is about 25% to about 50%.  
     
     
         16 . The method of  claim 1 , wherein the surface crosslinked polymer is evenly disbursed within the fibrous matrix.  
     
     
         17 . The method of  claim 1 , wherein the surface crosslinked polymer is poly(acrylic acid).  
     
     
         18 . The method of  claim 1 , wherein the surface crosslinked polymer comprises about 95% by weight of poly(acrylic acid) and about 3% by weight of a crosslinking agent.  
     
     
         19 . The method of  claim 18 , wherein the crosslinking agent is methylene bisacrylamide.  
     
     
         20 . The method of  claim 18 , wherein the surface crosslinked polymer additionally comprises a neutralizing agent.  
     
     
         21 . The method of  claim 20 , wherein the neutralizing agent is triethanol amine.  
     
     
         22 . The method of  claim 1 , wherein the wettable fibers are selected from the group consisting of natural fibers, synthetic fibers, and combinations thereof.  
     
     
         23 . The method of  claim 1 , wherein the wettable fibers are selected from the group consisting of wood pulp (fluff), cotton linters, polyethylene, polypropylene, polyesters, copolymers of polyesters and polyamides, and combinations thereof.  
     
     
         24 . The method of  claim 1 , wherein the wettable fibers are selected from the group consisting of wood pulp fibers, meltblown synthetic fibers and combinations thereof.

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