Basf Se Corporation

Jürgen Freiberg

Rudolf Schliwa

Norbert Herfert

Stephan Bauer

Thomas Daniel

Robert Bayer

Katrin Baumann

Birgit Reinhard

Marco Krüger

Karl Possemiers

Michael A Mitchell

Andreas Daiss

Christophe Bauduin

Karl J Possemiers

Katarzyna Dobrosielska-Oura

Michael Mitchell

The present invention relates to a process for producing surface-postcrosslinked water-absorbent polymer particles by coating of water-absorbent polymer particles having a content of residual monomers in the range from 0.03 to 15% by weight with at least one surface-postcrosslinker and thermal surface-postcrosslinking at temperatures in the range from 100 to 180&#xb0; C.

Process for producing surface-postcrosslinked water-absorbent polymer particles

An apparatus for producing pulverulent poly(meth)acrylate in a reactor for droplet polymerization having an apparatus for dropletization of a monomer solution for the production of the poly(meth)acrylate having holes through which the monomer solution is introduced, an addition point for a gas above the apparatus for dropletization, at least one gas withdrawal point on the circumference of the reactor and a fluidized bed, and above the gas withdrawal point the reactor has a region having a constant hydraulic internal diameter and below the gas withdrawal point the reactor has a hydraulic internal diameter that steadily decreases. The reactor has a heating means in the region having a steadily decreasing hydraulic internal diameter.

Apparatus for producing pulverulent poly(meth)acrylate

An apparatus for addition of droplets of a monomer solution for production of poly(meth)acrylate to a reactor for droplet polymerization, comprising at least one channel or a dropletizer head having, at its base, holes through which the solution is dropletized into the reactor, at least one of the following features being fulfilled:

Apparatus for addition of droplets of a monomer solution to a reactor

The present invention relates to a process for producing water-absorbent polymer particles by polymerizing droplets of a monomer solution comprising less than 0.3% by weight of persulfate and at least 0.05% by weight of azo initiator and thermal aftertreatment of the formed polymer particles at less than 100&#xb0; C. in a fluidized bed for 60 to 300 minutes.

Process for producing water-absorbent polymer particles by polymerizing droplets of a monomer solution

An apparatus for introducing droplets of a monomer solution for production of poly(meth)acrylate into a reactor for droplet polymerization, comprising at least one channel or a dropletizer head, the channel or the dropletizer head being sealed at its base by a dropletizer plate, the dropletizer plate having holes through which the monomer solution is introduced into the reactor, and the dropletizer plate being configured such that holes that, in an axially symmetric dropletizer plate or in an annular dropletizer plate or in one configured as a ring segment, are not on a center line of the dropletizer plate or, in the case of a circular dropletizer plate, are not at the center of the dropletizer plate are aligned such that monomer solution is introduced through the holes into the reactor at an angle to the vertical, and the holes in the case of a radial alignment of axially symmetric dropletizer plates being aligned such that the angle at which the monomer solution is introduced into the reactor decreases in the direction of the axis of the reactor and, in the case of dropletizer plates arranged parallel to one another or of concentrically arranged dropletizer plates, each being aligned on a line parallel to the center line or line running concentrically about the center, such that the angle at which the monomer solution is introduced into the reactor is constant.

Apparatus for introduction of droplets of a monomer solution into a reactor

The present invention relates to a process for producing water-absorbent polymer particles by polymerizing droplets of a monomer solution in a surrounding heated gas phase in a reactor comprising a gas distributor (), a reaction zone () and a fluidized bed (), the gas leaving the reactor is treated in a condenser column () with an aqueous solution, the treated gas leaving the condenser column () is recycled at least partly to the fluidized bed (), wherein the gas leaving the condenser column () comprises from 0.05 to 0.3 kg steam per kg dry gas and the steam content of the gas entering the gas distributor () is less than 80% of the steam content of the gas leaving the condenser column ().

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Lampertheim, Germany

Jürgen Freiberg