| abstract |
The present invention relates to a process for producing a water-absorbing polymer composition comprising the following treatment steps: (i) mixing (α1) 0.1 to 99.999% by weight, preferably 20 to 98.99% by weight, more preferably 30 to 98.95% by weight An acidic group-containing polymerized ethylenically unsaturated monomer or a salt thereof, or a polymerized ethylenically unsaturated monomer comprising a protonated or quarternized nitrogen, or a mixture thereof, particularly comprising A mixture of at least an ethylenically unsaturated monomer of an acidic group, preferably acrylic acid, is preferably (α2) from 0 to 70% by weight, preferably from 1 to 60% by weight, more preferably from 1 to 40% by weight. (α1) a polymerized polymer ethylenically unsaturated monomer, (α3) 0.001 to 10% by weight, preferably 0.01 to 7% by weight, more preferably 0.05 to 5% by weight, of one or more crosslinking agents, (α4) 0 to 30% by weight, preferably 1 to 20% by weight, more preferably 5 to 10% by weight, of the water-soluble polymer, and (α5) 0 to 20% by weight, preferably 0.01 to 7% by weight, more preferably 0.05 to 5 % by weight of one or more auxiliaries, wherein the total weight of (α1) to (α5) is 100% by weight; (ii) by cross-linking free radical polymerization to form a water-insoluble aqueous untreated hydrogel polymer (iii) grinding and drying the hydrogel polymer, (iv) grinding and screening the water-absorbing polymer as needed, (v) surface crosslinking the ground hydrogel polymer, and (vi) The water-absorbing polymer is dried and completed, wherein a blowing agent having a particle size of from 100 μm to 900 μm is added to the aqueous monomer solution before the addition of the initiator and the initiation of the radical polymerization. |