Water-absorbing polymer

摘要

The present invention relates to a process for producing a water-absorbent polysaccharide including the process steps of bringing into contact an uncrosslinked polysaccharide with a polyphosphate or a polyphosphoric acid as crosslinking agent in the presence of water to form a polysaccharide gel and crosslinking the polysaccharide gel. The invention further relates to a water-absorbent polysaccharide obtainable by this process, a water-absorbent polysaccharide, a composite, a process for producing a composite, a composite produced by this process, the use of the water-absorbent polysaccharides or of the composites as well as the use of polyphosphates.

主权项

1. A particulate, water-absorbent polycarboxypolysaccharide, wherein said polycarboxypolysaccharide is chemically modified with an average degree of carboxyl substitution within a range from 0.4 to about 1.5 and has (α1) an absorption under load value at a pressure of 0.9 psi within a range from 10 to 22 g/g and 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 and with a centrifuge retention capacity value within a range from 20 to 25 g/g, obtainable by a process comprising: a) providing an uncrosslinked polycarboxypolysaccharide; b) adding from about 0.001 to 20 wt. % based upon a weight of the polysaccharide of a crosslinking agent including polyphosphoric acid; c) adding an alkali hydroxide to neutralize the polycarboxypolysaccharide from step b) to at least about 50 mol %; and d) drying the polycarboxypolysaccharide to produce the water-absorbent polycarboxypolysaccharide.