Core for absorbent articles and method of making the same

Abstract

An absorbent core is provided for use in an absorbent article. The core includes a plurality of substantially continuous and coextensive filaments. At least some of the filaments have disposed on a surface thereof a layer comprising a superabsorbent material formed in place on the surface from a liquid superabsorbent polymer.

1 . An absorbent core for use in an absorbent article, the core comprising a plurality of substantially continuous and coextensive filaments, at least some of the filaments having disposed on a surface thereof a layer comprising a superabsorbent material formed in place on the surface from a liquid superabsorbent polymer.  
     
     
         2 . The absorbent core of  claim 1 , wherein the filaments are selected from the group consisting of RAYON, cellulose acetate, polypropylene, polyethylene, polyethylene terephthalate, and sheath-core bi-component filaments, and combinations thereof.  
     
     
         3 . The absorbent core of  claim 1 , wherein at least some of the filaments comprise cellulose acetate.  
     
     
         4 . The absorbent core of  claim 1 , wherein the surface of at least some of the filaments is hydrophilized.  
     
     
         5 . The absorbent core of  claim 1 , wherein substantially all of the filaments have disposed on said surface thereof said layer comprising the superabsorbent material.  
     
     
         6 . The absorbent core of  claim 1 , wherein the core comprises two or more adjacent and coextensive strata, wherein one stratum comprises filaments having disposed on said surface thereof said layer comprising the superabsorbent material, and another stratum is substantially free of superabsorbent material.  
     
     
         7 . The absorbent core of  claim 6 , wherein the another stratum comprises a surfactant disposed on the surface of at least some of the filaments.  
     
     
         8 . The absorbent article of  claim 1 , wherein the liquid superabsorbent material is selected from the group consisting of one or more superabsorbent polymers at least partially dissolved in a liquid carrier, a solution in a liquid carrier of one or more superabsorbent precursors, and a combination of one or more superabsorbent polymers and superabsorbent precursors.  
     
     
         9 . The absorbent core of  claim 1 , wherein the core has two opposing sides and the superabsorbent material is disposed in a pattern on one or both of the opposing sides.  
     
     
         10 . The absorbent core of  claim 1  further comprising pulp fibers Interspersed between at least some of the filaments.  
     
     
         11 . The absorbent core of  claim 1  further comprising superabsorbent polymer particles interspersed among at least some of the filaments.  
     
     
         12 . A method of making an absorbent core for use in an absorbent article, the method comprising: 
 a) expanding a tow comprising a plurality of substantially continuous and coextensive filaments, each filament having a surface; and    b) forming, from a liquid superabsorbent polymer, a layer comprising a superabsorbent material on the surface of at least some of the filaments.    
     
     
         13 . The method of  claim 12  wherein the forming step comprises: 
 applying to the expanded tow the liquid superabsorbent polymer to form a treated expanded tow comprising a liquid superabsorbent polymer coating; and    curing the treated expanded tow to form the layer comprising the superabsorbent material.    
     
     
         14 . The method of  claim 13  wherein the applying step comprises: 
 immersing the expanded tow in a bath comprising the liquid superabsorbent polymer;    removing the expanded tow from the bath; and    removing a portion of the liquid superabsorbent polymer coating.    
     
     
         15 . The method of  claim 13  wherein the applying step comprises spraying the liquid superabsorbent polymer on at least one surface of the expanded tow.  
     
     
         16 . The method of  claim 13  wherein the curing step comprises exposing the treated expanded tow to heat.  
     
     
         17 . The method of  claim 13  wherein the curing step comprises exposing the treated expanded tow to radiation.  
     
     
         18 . The method of  claim 12 , wherein the core has two opposing sides, and wherein the forming step comprises patternwise spraying the liquid superabsorbent polymer on one or both of the sides.  
     
     
         19 . The method of  claim 12 , wherein the core has two opposing sides, and wherein the forming step comprises spraying the liquid superabsorbent polymer on one of the sides, the method further comprising applying a surfactant to at least some of the filaments on the other side.  
     
     
         20 . The method of  claim 12  further comprising partially separating the filaments to form the expanded tow.  
     
     
         21 . The method of  claim 20  wherein the step of partially separating comprises blowing the tow with jets of air.  
     
     
         22 . The method of  claim 12  further comprising at least partially flattening the tow.  
     
     
         23 . The method of  claim 12  further comprising interspersing pulp fibers between at least some of the filaments.  
     
     
         24 . The method of  claim 12  further comprising interspersing superabsorbent polymer particles between at least some of the filaments.  
     
     
         25 . The method of  claim 12  further comprising hydrophilizing at least some of the filaments.  
     
     
         26 . The method of  claim 12  wherein the forming step comprises forming a layer on substantially all of the filaments.  
     
     
         27 . The method of  claim 12  further comprising, after the forming step, removing one or both of water and residual volatile reactants from the formed layer.  
     
     
         28 . The method of  claim 12  further comprising, after the forming step, tenderizing the filaments having thereon said layer comprising the superabsorbent material.  
     
     
         29 . A system for making an absorbent core for use in an absorbent article, the system comprising: 
 a) means for applying a liquid superabsorbent polymer to a tow comprising a plurality of substantially continuous and coextensive filaments, thereby forming a treated expanded tow comprising a liquid superabsorbent polymer coating on the surface of at least some of the filaments; and    b) means for forming, from the liquid superabsorbent polymer coating, a layer comprising a superabsorbent material on said surface of said at least some of the filaments.    
     
     
         30 . The system of  claim 29 , wherein the means for applying comprises a bath.  
     
     
         31 . The system of  claim 29 , wherein the means for applying comprises a spray nozzle.  
     
     
         32 . The system of  claim 29 , wherein the core comprises two opposing sides, and wherein the means for applying comprises a spray nozzle configured to apply the liquid superabsorbent polymer on one or both of the sides in a pattern.  
     
     
         33 . The system of  claim 29 , wherein the core comprises two opposing sides, the system further comprising means for applying a surfactant to the expanded tow.  
     
     
         34 . The system of  claim 29 , wherein the means for forming comprises a heater.  
     
     
         35 . The system of  claim 29 , wherein the means for forming comprises a radiation source.  
     
     
         36 . The system of  claim 29  further comprising means for removing a portion of the liquid superabsorbent polymer coating.  
     
     
         37 . The system of  claim 29  further comprising means for interspersing pulp fibers between at least some of the filaments.  
     
     
         38 . The system of  claim 29  further comprising means for interspersing superabsorbent polymer particles between at least some of the filaments.  
     
     
         39 . The system of  claim 29  further comprising means for flattening the tow.  
     
     
         40 . The system of  claim 29  further comprising means for partially separating filaments of the tow, thereby forming the expanded tow  
     
     
         41 . The system of  claim 40  wherein the means for partially separating comprises a source of air positioned to direct jets of air toward the tow.  
     
     
         42 . The system of  claim 29  further comprising means for removing one or both of water and residual volatile reactants from the formed layer.  
     
     
         43 . The system of  claim 29  further comprising means for tenderizing the filaments having thereon a layer comprising a superabsorbent material.