SUPERABSORBENT POLYMERS WITH RAPID ABSORPTION PROPERTIES AND PROCESS FOR PRODUCING SAME

摘要

The present invention relates to a process for producing a water-absorbing polymer, comprising the steps of (i) mixing (α1) from 0.1 to 99.999% by weight, preferably from 20 to 98.99% by weight and particularly preferably from 30 to 98.95% by weight, of polymerizable, ethylenically unsaturated monomers containing acid groups, or salts of said monomers, or polymerizable, ethylenically unsaturated monomers including a protonated or quaternized nitrogen, or a mixture of these, where preference is given to mixtures at least including ethylenically unsaturated monomers containing acid groups, preferably acrylic acid, (α2) from 0 to 70% by weight, preferably from 1 to 60% by weight and particularly preferably from 1 to 40% by weight, of polymerized, ethylenically unsaturated monomers copolymerizable with (α1), (α3) from 0.001 to 10% by weight, preferably from 0.01 to 7% by weight and particularly preferably from 0.05 to 5% by weight, of one or more crosslinking agents, (α4) from 0 to 30% by weight, preferably from 1 to 20% by weight and particularly preferably from 5 to 10% by weight, of water-soluble polymers, and (α5) from 0 to 20% by weight, preferably from 0.01 to 7% by weight and particularly preferably from 0.05 to 5% by weight, of one or more auxiliaries, where the total of the quantities by weight of (α1) to (α5) is 100% by weight, (ii) free-radical polymerization with crosslinking, in order to form a water-insoluble, aqueous untreated hydrogel polymer, (iii) drying of the hydrogel polymer, (iv) grinding and isolation by sieving of the water-absorbing polymer, (v) surface post-crosslinking of the ground and sieved hydrogel polymer and (vi) drying and finishing of the water-absorbing polymer, where the following are added to the aqueous monomer solution: before the addition of the initiator and the start of the free-radical polymerization from 0.01 to 5% by weight, preferably from 0.02 to 2% by weight and particularly preferably from 0.07 to 1% by weight, of at least one surfactant from the group of the non-ionic unsaturated polyether copolymers, and optionally from 0.01 to 5% by weight, preferably from 0.02 to 2% by weight and particularly preferably from 0.07 to 1% by weight, of a blowing agent with particle size from 10 μm to 900 μm, based on the water-absorbing polymer, a process for producing a hydrogel polymer, the product of the process, and the use.