Patent ID: 8796343

Claim:
A method of preparing a water-absorbent open-celled crosslinked acid-functional hydrogel foam comprising: (a) preparing a polymerizable aqueous mixture containing (i) from 10 to 80%, by weight, of acid-functional monoethylenically unsaturated monomers which are partially neutralized, (ii) optionally up to 50%, by weight, of other monoethylenically unsaturated monomers, (iii) from 0.001 to 5%, by weight, of a crosslinker, (iv) at least one initiator, and (v) from 0.1 to 20%, by weight, of at least one surfactant; (b) foaming the polymerizable aqueous mixture of step (a); (c) polymerizing the foamed mixture of step (b) to form a hydrogel foam; then (d) applying to a surface of the hydrogel foam of step (c) at least one surfactant and optionally a finely divided silicon dioxide, wherein an amount of the surfactant on the surface of the hydrogel foam is in the range from 0.1 to 10% by weight, based on the weight of the foam.