Patent ID: 8653215

Claim:
A process for producing water-absorbing polymer particles by polymerizing a monomer solution or suspension comprising a) an ethylenically unsaturated monomer which bears an acid group and may be at least partly neutralized, b) at least one crosslinker, c) at least one initiator, d) optionally one or more ethylenically unsaturated monomer copolymerizable with the monomers specified under a), and e) optionally one or more water-soluble polymer, in a kneader with a reaction volume of at least 0.1 m 3 and at least two shafts in axially parallel rotation, with a plurality of kneading and transporting elements present on the shafts bringing about conveying of a reaction mixture added at a start of the kneader in axial direction to an end of the kneader, wherein the monomer solution comprises from 0.01 to 0.2% by weight of initiator c), based on unneutralized monomer a), the front of at least 50% of an outer kneader wall is trace-heated and a temperature of the trace heating is at least 110° C.