SUPER-ABSORBING POLYMERS WITH RAPID ABSORPTION PROPERTIES AND METHOD FOR PRODUCING THE SAME

摘要

This invention relates to a method for producing a water-absorbing polymer, including the following steps: (i) mixing (α1) 0.1 to 99.999 wt%, preferably 20 to 98.99 wt%, and particularly preferably 30 to 98.95 wt% polymerizable, ethylenically unsaturated, acid-group-containing monomers or their salts, or polymerizable, ethylenically unsaturated, monomers containing a protonated or quaternized nitrogen atom, or their mixtures, wherein mixtures containing at least ethylenically unsaturated, acid-group containing monomers, preferably acrylic acid, are especially preferred; (α2) 0 to 70 wt%, preferably 1 to 60 wt%, and particularly preferably 1 to 40 wt% polymerized, ethylenically unsaturated, monomers that are copolymerizable with (α1); (α3) 0.001 to 10 wt%, preferably 0.01 to 7 wt%, and particularly preferably 0.05 to 5 wt% one or more cross-linking agent(s); (α4) 0 to 30 wt%, preferably 1 to 20 wt%, and particularly preferably 5 to 10 wt% water-soluble polymers; and (α5) 0 to 20 wt%, preferably 0.01 to 7 wt%, and particularly preferably 0.05 to 5 wt% one or more additive(s), wherein the total quantity by weight of (α1) to (α5) amounts to 100 wt%, (ii) radical polymerization while cross-linking, in order to form a water-insoluble, aqueous untreated hydrogel polymer, (iii) drying the hydrogel polymer, (iv) grinding and sifting the water-absorbing polymer, (v) surface post-cross-linking the ground and sifted hydrogel polymer, and (vi) drying and processing the water-absorbing polymer, wherein, before the admixture of the initiator and the start of radical polymerization, 0.01 to 5 wt%, preferably 0.02 to 2wt%, and particularly preferably 0.07 to 1 wt% of at least one surfactant, relative to acrylic acid, from the group of non-ionic, ionic or amphoteric surfactants and, if required, 0.01 to 5 wt%, preferably 0.02 to 2 wt%, and particularly preferably 0.07 to 1 wt% foaming agent with a particle size of 10 µm to 900 µm, are added, relative to the water-absorbing polymer; method for producing a hydrogel polymer; the product obtained by this method; and use.