Water absorbent material and absorbent article using same

Abstract

The water absorbent material of the present invention is composed of a copolymer of an anhydropolyamino acid having at least one ethylenically unsaturated double bond in a molecule, a water-soluble monomer having an ethylenically unsaturated double bond and polysaccharides, and has high water absorption ratio and high water absorption rate in pure water or water having a low ion content and also has high absorption properties for high concentration salt-containing solutions.

1 - 9 . (canceled)  
     
     
         10 . A water absorbent material comprising a copolymer of an anhydropolyamino acid having at least one ethylenically unsaturated double bond in a molecule (A), a water-soluble monomer having an ethylenically unsaturated double bond (B), and polysaccharides (C).  
     
     
         11 . A water absorbent material according to  claim 10 , wherein the anhydropolyamino acid having at least one ethylenically unsaturated double bond in a molecule (A) is a reaction product of an anhydropolyamino acid having no ethylenically unsaturated double bond in a molecule (A-1) and a compound which has an ethylenically unsaturated double bond and a functional group having reactivity with the anhydropolyamino acid (A-1) in a molecule (A-2).  
     
     
         12 . A water absorbent material according to  claim 10 , wherein the copolymer comprises gel particles.  
     
     
         13 . A water absorbent material according to  claim 11 , wherein the compound which has an ethylenically unsaturated double bond and a functional group having reactivity with the anhydropolyamino acid (A-1) in a molecule (B) is a compound represented by the following general formula [I]:  
       
         
           
           
               
               
           
         
       
       wherein R 1  represents at least one functional group selected from the group consisting of amino group, epoxy group, carboxyl group, carbodimide group, oxazoline group, imino group and isocyanate group, Q represents an alkylene group having 1 to 10 carbon atoms, and R 2  represents hydrogen or an alkylene group having 1 to 4 carbon atoms.  
     
     
         14 . A water absorbent material according to  claim 11 , wherein the anhydropolyamino acid having no ethylenically unsaturated double bond in a molecule (A-1) is polysuccinimide.  
     
     
         15 . A water absorbent material according to  claim 10 , wherein a portion or all of the anhydropolyamino acid having an ethylenically unsaturated double bond in a molecule (A) is hydrolyzed.  
     
     
         16 . A water absorbent material according to  claim 10 , wherein a water absorption ratio of a physiological saline solution is 10 g/g or more.  
     
     
         17 . (canceled)  
     
     
         18 . An absorbent article comprising an absorber comprising a water absorbent material and a fiber material arranged between a liquid-permeable sheet and a liquid-impermeable sheet, wherein the water absorbent material is a water absorbent material comprising a copolymer of an anhydropolyamino acid having at least one ethylenically unsaturated double bond in a molecule (A), a water-soluble monomer having an ethylenically unsaturated double bond (B), and polysaccharides (C).  
     
     
         19 . (canceled)  
     
     
         20 . An absorbent article according to  claim 18 , wherein the copolymer comprises gel particles.