Patent ID: 8580953

Claim:
A process for producing a particulate water-absorbent polycarboxypolysaccharide wherein said water-absorbent polycarboxypolysaccharide is chemically modified with an average degree of carboxyl substitution within the range from 0.4 to about 1.5 and has a (α1) an absorption under load value at a pressure of 0.9 psi within a range from 10 to 22 g/g with a centrifuge retention capacity value within a range from 15 to 20 g/g; or (α2) an absorption under load value at a pressure of 0.9 psi within a range from 6 to 20 g/g with a centrifuge retention capacity value within a range from 20 to 25 g/g, the process comprising the steps of: a) preparing an aqueous solution having a pH of from about 8 to about 12 by mixing a polycarboxypolysaccharide with a crosslinking agent consisting essentially of polyphosphoric acid in an amount within a range from 0.001 to 20 wt. %, based upon the weight of the polycarboxypolysaccharide, in the presence of water to form said water-absorbent polycarboxypolysaccharide, wherein the mixing step occurs in a kneader wherein the kneader has at least two kneading shafts; and b) drying the water-absorbent polycarboxypolysaccharide gel on a belt drier at a temperature of from about 120° C. to about 130° C. for a time period of from about 50 minutes to about 150 minutes.