Patent ID: 8658146

Claim:
A water-absorbing composition comprising a) surface crosslinked water-absorbing polymer structures having a surface, wherein the water-absorbing polymer structures are based on partly neutralized, crosslinked polyacrylates; b) from about 0.01 to 1 wt. %, based on the total weight of the water-absorbing composition, of a hydrolysable gallotannin located on the surface of the surface crosslinked water-absorbing polymer structures, wherein said hydrolysable gallotannin has a number-average molecular weight of at least about 1,000 g/mol or a weight-average molecular weight of at least 1,000 g/mol; wherein said hydrolysable gallotannin is derived from β-1,2,3,4,6-pentagalloyl-O-D-glucose; wherein to at least one of the OH groups of at least one of the gallic acid molecules bonded to the carbohydrate core there is bonded a further gallic acid molecule via an ester bond; wherein at least 30 wt. % of the tannins contained in the water-absorbing composition have an average molecular weight of more than about 940 g/mol; and wherein said hydrolysable gallotannin is at least partially in the form of particles on the surface of the water-absorbing polymer structures; and c) from about 0.01 to about 1 wt. %, based on the total weight of the water-absorbing polymer structures, of a complex forming agent located on the surface of the surface crosslinked water-absorbing polymer structures, wherein said complex forming agent comprises two or more functional groups selected from the group consisting of organic acid groups, amine or imine groups, and sulfonic acid groups, wherein the water-absorbing composition has at least one of the following properties: (β1) a retention, determined in accordance with ERT 441.2-02, of at least 20 g/g; (β2) an absorption, determined in accordance with ERT 442.-2-02, (in the case of particles for the total particle size fraction) against a pressure of 0.7 psi (50 g/cm 2 ) of at least 15 g/g; and (β3) a degree of neutralization of the polyacrylates of at least 50 mol % and at most 70 mol %.