Superabsorbent polymers with rapid absorption properties and process for producing same

A process for producing a water-absorbing polymer composition, comprising the process steps of

• (i) mixing
• (α1) 0.1 to 99.999% by weight of polymerizable, ethylenically unsaturated monomers containing acid groups, or salts thereof, or polymerizable, ethylenically unsaturated monomers including a protonated or quaternized nitrogen, or mixtures thereof,
• (α2) 0 to 70% by weight of polymerizable, ethylenically unsaturated monomers copolymerizable with (α1),
• (α3) 0.001 to 10% by weight of one or more crosslinkers,
• (α4) 0 to 30% by weight of water-soluble polymers, and
• (α5) 0 to 20% by weight of one or more assistants, where the sum of the weights of (α1) to (α5) is 100% by weight,
• (ii) free-radical polymerization with crosslinking to form a water-insoluble, aqueous untreated hydrogel polymer,
• (iii) drying the hydrogel polymer,
• (iv) grinding and sieving the hydrogel polymer to size,
• (v) surface postcrosslinking the ground and sieved hydrogel polymer and
• (vi) drying and finishing the water-absorbing polymer
• wherein
• 0.01 to 5% by weight of a blowing agent having a particle size of 10 μm to 900 μm are added, based on the hydrogel polymer, optionally 0.01 to 5% by weight of at least one surfactant from the group of the nonionic, ionic or amphoteric surfactants, and in steps (ii) to (v) additionally at least one acidic compound is added.