Water absorbing foamed hydrogel for absorption of body fluids, wound protection, as sealing material, packaging, slime dewatering, absorption of acidic waste, thickening of waterborne paints, dewatering of oils or hydrocarbons

摘要

A water absorbing foamed hydrogel obtainable from a polymerization mixture of acid group containing monoethylenically unsaturated (MEU), crosslinker, initiators, surfactant, solvent, and a cell nucleus former, where during foaming a gas inert to radicals is dissolved in the aqueous mixture. A water absorbing foamed hydrogel obtainable by (I): foaming an aqueous polymerization mixture of: (a) acid group containing monoethylenically unsaturated monomers (MUM) at least 50% neutralized, (b) optionally other MUM, (c) a crosslinker, (d) initiators, (e) at least one surfactant, (f) optionally at least one solvent, and (g) a cell nucleus former, where during foaming a gas at a pressure of 2-400 bar and inert to radicals is dissolved in the aqueous mixture, the mixture is adjusted to atmospheric pressure, so that a foam is obtained by dispersion of the fine bubbles of inert gas, and (II): the foamed mixture is polymerized with formation of a foamed hydrogel, and the water content of the polymerizate is adjusted to 1-60 wt.%. Independent claims are included for: (1) a process for preparation of the hydrogels as described above, where the crosslinker is a (meth) acrylic acid esterified addition product of 6-24 mole ethylene oxide and 1 mole trimethylol propane; and (2) polymerization of a nonwoven impregnated with the foamed polymerization mixture.