| abstract |
The invention concerns insoluble powder-form water-swellable crosslinked polymers capable of absorbing aqueous or serous fluids, the polymers being made up of: a) 55-99.9 % by wt. of polymerized insaturated acid-group-containing monomers which are at least 25 mol % neutralized, b) 0-40 % by wt. of polymerized unsaturated monomers which are copolymerizable with (a), c) 0.1-5.0 % by wt. of a crosslinking agent, and d) 0-30 % by wt. of a water-soluble polymer, the amounts of (a) to (d) being expressed relative to the anhydrous polymer. The polymer powder is heated to a temperature of 150-250 °C with an at least bifunctional compound capable of reacting with acids to crosslink the surface and the surface-crosslinked polymer powder is subjected to a further surface-crosslinking treatment at a temperature of 150-250 °C with an at least bifunctional compound capable of reacting with acids. The invention also concerns a method of preparing polymers of this kind and their use as absorbents for water and aqueous liquids, in particular in articles designed to absorb body fluids and in current-carrying or light-carrying cables, as a component of packaging material, as a soil improver and as artificial soil for use in plant breeding. |