Acidic superabsorbent polysaccharides

Abstract

A process is disclosed for producing an acidic superabsorbent polysaccharide derivative, comprising the steps of. (a) crosslinking at least one polysaceharide containing acidic groups, such as carboxymethyl cellulose and/or 6-carboxy stanch, with a crosslinking agent to produce a gel; (b) if necessary, adjusting the pH of the polysaccharide to a value between 3.5 and 5.5; (c) comminuting the acidified polysaccharide gel; and (d) drying the comminuted polysaccharide at elevated temperature. The superabsorbent polysaccharide obtainable by this process has a pH below 5 and provides odour control when contacted with malodorous fluids.

1 - 15 . (Cancelled)  
     
     
         16 . A superabsorbent polysaccharide derivative obtained by the process of: 
 (a) crosslinking at least one polysaccharide containing acidic groups with a crosslinking agent to produce a gel;    (b) ensuring that the pH of the polysaccharide is between 3.5 and 5.5;    (c) comminuting the acidified polysaccharide gel; and    (d) drying the comminuted polysaccharide at elevated temperature;    the superabsorbent polysaccharide derivative, when wetted, having a pH below 5.    
     
     
         17 . A superabsorbent polysaccharide derivative according  claim 16 , also comprising an acid selected from organic di- and polycarboxylic acids, hydroxycarboxylic acids and benzoic acids.  
     
     
         18 . An absorbent article comprising a superabsorbent polysaccharide derivative according to  claim 16 .  
     
     
         19 . A superabsorbent polysaccharide derivative, the polysaccharide derivative containing acidic groups and being crosslinked, comminuted and dried, and, when wetted, having a pH below 5.  
     
     
         20 . A superabsorbent polysaccharide derivative according to  claim 19 , also comprising an acid selected from organic di- and polycarboxylic acids, hydroxycarboxylic acids and benzoic acids.  
     
     
         21 . A superabsorbent polysaccharide derivative according to  claim 19 , in which the polysaccharide containing acidic groups comprises carboxymethyl-cellulose.  
     
     
         22 . A superabsorbent polysaccharide derivative according to  claim 19 , in which the polysaccharide containing acidic groups is a carboxymethyl polysaccharide further containing carboxyl groups resulting from oxidation of saccharidic hydroxymethyl or hydroxymethylene groups, or phosphonic or sulphonic acid groups.  
     
     
         23 . A superabsorbent polysaccharide derivative according to  claim 19 , in which the polysaccharide containing acidic groups comprises a 6-carboxy polysaccharide.  
     
     
         24 . A superabsorbent polysaccharide derivative according to  claim 23 , in which the polysaccharide containing acidic groups comprises a 6-carboxy polysaccharide mixed with a carboxyalkylated polysaccharide.  
     
     
         25 . A superabsorbent polysaccharide derivative according to  claim 19 , in which the polysaccharide containing acidic groups contains 0.3-3.0 carboxyl groups per monosaccharide unit.  
     
     
         26 . An absorbent hygiene article comprising a superabsorbent polysaccharide, the polysaccharide containing acidic groups and being crosslinked, comminuted and dried, and, when wetted, having a pH below 5.  
     
     
         27 . An absorbent hygiene article according to  claim 26 , in which the polysaccharide containing acidic groups contains 0.3-3.0 carboxyl groups per monosaccharide unit.  
     
     
         28 . An absorbent hygiene article according to  claim 26 , in which the polysaccharide containing acidic groups comprises 6-carboxy starch.  
     
     
         29 . A method of absorbing liquids, comprising contacting the liquid with a superabsorbent polysaccharide derivative, the polysaccharide derivative containing acidic groups and being crosslinked, comminuted and dried, and, when wetted, having a pH below 5.