The present invention relates generally to (i) carboxylic acid groups at least partially neutralized containing, monoethylenically unsaturated monomers ( 1) and an aqueous monomer solution comprising at least one cross-linking agent ( 3) preparing a ( ) be in the aqueous monomer solution comprising the steps of optionally added to the fine particles of the absorbent polymer ( ) the step of adding at least one component of the polymerization initiator system comprises a polymerization initiator or two or more components in the aqueous monomer solution (Iv) reducing the oxygen content of the aqueous monomer solution (V) the step of filling the polymerization reactor the aqueous monomer solution (Vi) the polymerization to obtain a polymer gel by polymerizing a monomer in the aqueous monomer solution in the polymerization reactor ( ) to obtain a polymer gel particles was pulverized and, optionally, wherein the step of releasing a polymer gel polymer gel out of the polymerization reactor, whereby ( ) drying the polymer gel particles Obtaining a water-absorbent polymer particles - (ix) particles can ppatah whereby the polymer gel particles the dried Arranging the water absorbent polymer particles by size - (x) be the binary ppatah And (xi) the number of ppatah are arranged in order of size - a step to process the surface of the water absorbent polymer particles Preparation of the aqueous monomer solution in the process steps (i) where: (ia) a polymerization step of obtaining an aqueous solution of an at least partially neutralized acrylic acid was obtained by mixing an aqueous solution of sodium hydroxide and acrylic acid at least partially neutralized acrylic acid (Ib) a heat exchanger comprising the step of (2) cooling the aqueous solution of the at least partially neutralized acrylic acid as a cooling liquid in and, wherein the cooling liquid using a heat exchanger, where at least a column of heated cooling liquid obtained in the heat exchanger (2) can be part of the c
