Patent ID: 6455600
Filing Date: 2002-09-24
Classification: A61L,C08J

Abstract:
A water-absorbing, expanded, crosslinked polymer obtainable by(I) foaming a polymerizable aqueous mixture which comprises (a) monoethylenically unsaturated monomers which contain acidic groups and are optionally neutralized, (b) optionally other monoethylenically unsaturated monomers, (c) crosslinkers, (d) initiators, (e) 0.1-20% by weight of at least one surfactant, (f) optionally at least one solubilizer and (g) optionally thickeners, foam stabilizers, polymerization regulators, fillers and/or cell nucleating agents, â€ƒwhere the foaming takes place by dispersing fine bubbles of a gas which is inert to free radicals into the polymerizable aqueous mixture, and (II) polymerizing the foamed mixture to form an expanded hydrogel and, where appropriate, adjusting the water content of the expanded polymer to 1-60% by weight, if at least 20 mol % of the monomers (a) which contain acidic groups have been neutralized with tertiary alkanolamines and/or the free acidic groups of the expanded hydrogel have been at least 20 mol % neutralized with at least one alkalolamine after the polymerization.