Patent ID: 8790003

Claim:
A method for adding at least one solid or viscous liquid additive, to a reactor interior of a reactor for preparing crosslinked, finely divided polymers, wherein the at least one additive is a solid additive or a viscous liquid additive, or an additive dispersed in a solvent, by copolymerizing an aqueous solution comprising (a) water-soluble, monoethylenically unsaturated monomers and (b) from 0.001 to 5 mol %, based on the monomers (a), of monomers comprising at least two polymerizable groups, (c) from 0 to 20 mol %, based on the monomers (a), of water-insoluble monoethylenically unsaturated monomers, wherein the at least one additive is added by an apparatus comprising at least one screw for conveying the at least one additive, the at least one screw ends in an addition orifice substantially flush with the inner wall of the reactor interior, the at least one additive is fed into a region of maximum mixing, and the at least one screw is flushed with an inert gas.