Superabsorbent polymers with improved odor control properties and process for their preparation

摘要

The present invention relates to a water-absorbing polymer and a process for the preparation, comprising the process steps of (i) mixing (α1) from 0.1 to 99.999% by weight, preferably from 20 to 98.99% by weight and more preferably from 30 to 98, 95 wt .-% polymerizable, ethylenically unsaturated, acid group-containing monomers or their salts or polymerizable, ethylenically unsaturated, a protonated or quaternized nitrogen-containing monomers, or mixtures thereof, wherein at least ethylenically unsaturated, acid group-containing monomers, preferably acrylic acid-containing mixtures are particularly preferred (α2) 0 to 70 wt .-%, preferably 1 to 60 wt .-% and particularly preferably 1 to 40 wt .-% polymerized, ethylenically unsaturated, with (α1) copolymerizable monomers, (α3) 0.001 to 10 wt. %, preferably 0.01 to 7 wt .-% and particularly preferably 0.05 to 5 wt .-% of one or more crosslinkers, (α4) 0 to 30 wt .-%, preferably 1 to 20 wt .-% and un d particularly preferred 5 to 10 wt .-% water-soluble polymers, (α5) 0-90 wt .-%, preferably 2.5-75 wt .-% and particularly preferably 10-60 wt .-% water, and (α6) 0-20 wt .-%, preferably 0-10 wt .-% and particularly preferably 0.1-8 wt .-% of one or more auxiliaries, wherein the sum of the amounts by weight (α1) to (α6) 100 wt .-% (ii) free radical polymerization with crosslinking to form a water-insoluble, aqueous untreated hydrogel polymer, (iii) comminuting the hydrogel polymer, (iv) drying the hydrogel polymer, (v) milling and screening the water-absorbent polymer, (vi) surface postcrosslinking the ground and screened hydrogel polymer; and (vii) forming the water absorbent polymer, wherein the water absorbent is from 0.0001 to 3% by weight, preferably 0.0002 to 2% by weight, and more preferably 0.0007 to 1.8 wt .-% of a peroxo compound, based on the acrylic acid is treated after the polymerization, and a V for the preparation of a hydrogel polymer, the product of the process, and the use.