The invention generally relates to a process for the preparation of water-absorbent polymer particles, comprising the process steps of (i) preparing an aqueous monomer solution comprising at least one partially neutralized, monoethylenically unsaturated monomer bearing carboxylic acid groups (α1) and at least one crosslinker (α3)； (ii) optionally adding fine particles of a water-absorbent polymer； (iii) adding a polymerization initiator or a at least one component of a polymerization initiator system that comprises two or more components to the aqueous monomer solution； (iv) optionally decreasing the oxygen content of the aqueous monomer solution； (v) charging the aqueous monomer solution onto a belt of a polymerization belt reactor； (vi) polymerizing the monomers, thereby obtaining a polymer gel； (vii) discharging the polymer gel from the belt and optionally comminuting the polymer gel； (viii) drying the optionally comminuted polymer gel； (ix) grinding the dried polymer gel thereby obtaining water-absorbent polymer particles； (x) sizing the grinded water-absorbent polymer particles； and (xi) optionally treating the surface of the grinded and sized water-absorbent polymer particles； wherein one of the process steps (i) to (vi) further comprises, adding a blowing agent in an amount in a range from 500 to 4000 ppm, based on the total weight of the monoethylenically unsaturated monomers； and wherein the polymer gel obtained in step (vi) has a water content in the range from 40 to 60 wt.-%, based on the total weight of the polymer gel； and wherein during the drying step (viii) water is removed from the polymer gel in a rate in the range from 120 to 240 kg/minute and the obtained dried polymer gel has a water content in the range from 3 to 7 wt.-%, based on the total weight of the dried polymer gel.De manière générale, l'invention concerne un procédé de préparation de particules de polymère absorbant l'eau, comprenant les étapes de procédé de (i) préparation d'une soluti
