| abstract |
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 % polymerizable, ethylenically unsaturated, acid-group-containing monomers; (α2) 0 to 70 wt % polymerized ethylenically unsaturated, monomers copolymerizable with (α1); (α3) 0.00 1 to 10 wt %, cross-linking agent(s); (α4) 0 to 30 wt % water-soluble polymers; and (α5) 0 to 20 wt % 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 hydrogel polymer, (iii) drying the hydrogel polymer, (iv) grinding and sifting the water-absorbing polymer, (v) surface post-cross-linking the hydrogel polymer, and (vi) drying and processing the polymer, wherein, before the admixture of the initiator and the start of radical polymerization, 0.01 to 5 wt % of a surfactant, relative to acrylic acid, 0.01 to 5 wt % foaming agent, are added. |