Method for producing water-absorbing polymer particles

Abstract

A process for producing water-absorbing polymer particles, comprising the addition of a solid additive to a polymer gel by means of a conveying screw ( 1 ), wherein the solid additive and a gas volume flow are fed to the conveying screw ( 1 ) by means of an addition channel ( 2 ).

1 .- 10 . (canceled) 
     
     
         11 . A process for producing water-absorbing polymer particles by polymerizing an aqueous monomer solution or suspension comprising
 a) at least one ethylenically unsaturated monomer which bears acid groups and may be at least partly neutralized,   b) at least one crosslinker,   c) optionally one or more ethylenically and/or allylically unsaturated monomer copolymerizable with the monomer mentioned under a), and   d) optionally one or more water-soluble polymers,   in a kneading reactor, which comprises metering an inert gas into the kneading reactor via at least two addition points.   
     
     
         12 . The process according to  claim 11 , wherein a flow velocity of the inert gas in the kneading reactor is not less than 0.05 m/s in any gas-filled volume element of the kneading reactor. 
     
     
         13 . The process according to  claim 11 , wherein the inert gas is nitrogen. 
     
     
         14 . The process according to  claim 11 , wherein the water-absorbing polymer particles have a centrifuge retention capacity of at least 15 g/g.