The present invention generally comprises the steps of: (i) preparing an aqueous monomer solution comprising at least one partially neutralized monoethylenically unsaturated monomer having a carboxylic acid group (α1) and at least one crosslinking agent (α3); (ii) optionally, adding absorbent polymer microparticles to the aqueous monomer solution; (iii) adding a polymerization initiator or one or more constituents of a polymerization initiation system comprising two or more constituents to the aqueous monomer solution; (iv) optionally, lowering the oxygen content of the aqueous monomer solution; (v) filling an aqueous monomer solution onto the belt of the polymerization belt reactor; (vi) polymerizing a monomer in an aqueous monomer solution on a belt to obtain a polymer gel; (vii) polymerization ?訶? Discharging the polymer gel from the reactor and optionally crushing the polymer gel; (viii) optionally, drying the crushed polymer gel; (ix) pulverizing the dried polymer gel to obtain absorbent polymer particles; (x) classifying the pulverized absorbent polymer particles; And (xi) optionally, treating the surface of the pulverized and classified absorbent polymer particles, the belt being shaped as a longitudinally extending trough over at least 30% of the longitudinally extending portion of the belt, , The trough is directed to a method for producing absorbent polymer particles comprising a first region and an additional region.