Basf Se Corporation

Basf Aktiengesellschaft

Annemarie Hillebrecht

Matthias Weismantel

Rüdiger Funk

Wilfried Heide

Stefan Blei

Dominicus Van Esbroeck

Dennis Loesch

Thomas Daniel

Norbert Herfert

Uwe Stueven

Marco Krüger

Oskar Stephan

Monte Alan Peterson

Ronny De Kaey

Volker Seidl

Leo Van Miert

Karl J Possemiers

Dennis Lösch

Ruediger Funk

Siegfried Chszaniecki

Bernd Brian

Huanmin Wei

Uwe Stüven

Asif Karim

Carolin Nadine Dücker

Andrea Karen Bennett

Michael Young

Tom Woodrum

William G-J Chiang

A process for preparing water-absorbing polymer beads with high permeability by polymerizing droplets of a monomer solution, comprising monomers bearing acid groups, in a gas phase surrounding the droplets, wherein the monomer solution comprises polyvalent cations and the polymer beads have a mean diameter of at least 150 &#x3bc;m.

Method for producing water-absorbent polymer particles with a higher permeability by polymerising droplets of a monomer solution

The invention relates to the use of an apparatus for adding at least one solid or viscous liquid additive, or an additive dispersed in solvent, to a reactor interior of a reactor for preparing crosslinked, finely divided polymers by copolymerizing

Use of an apparatus for adding at least one additive to a receptor interior

A process for producing polymer particles by polymerizing liquid droplets in a gas phase surrounding the droplets, said droplets comprising at least one monomer and being coated with particulate solids during the polymerization.

Method for producing polymer particles by the polymerization of liquid droplets in a gas phase

A process for preparing water-absorbing polymer beads with high permeability by polymerizing droplets of a monomer solution in a gas phase surrounding the droplets, wherein a water-insoluble inorganic salt is suspended in the monomer solution and the polymer beads have a mean diameter of at least 150 &#x3bc;m.

Method for producing water-absorbent polymer particles with a higher permeability by polymerizing droplets of a monomer solution

A process for preparing postcrosslinked water-absorbing polymer beads with high absorption by polymerizing droplets of a monomer solution in a gas phase surrounding the droplets, wherein the solids content of the monomer solution is at least 35% by weight and the polymer beads have a mean diameter of at least 150 &#x3bc;m.

Method for producing post-cured water-absorbent polymer particles with a higher absorption by polymerizing droplets of a monomer solution

The invention relates to a process for producing a water-absorbing resin by polymerization of a reaction mixture comprising at least one hydrophilic monomer and, if appropriate, at least one crosslinker in a reactor, which comprises admixing the reaction mixture with at least one first portion of a particulate additive before the reaction mixture has reached a residence time of 40% of the overall residence time in the reactor and with at least one second portion of a particulate additive when the reaction mixture has reached a residence time of 45% or more of the overall residence time in the reactor, the additive being selected from water-absorbing resin powders, fillers and mixtures thereof, the total solids content of monomer and additive being in the range from 30% to 60% by weight, the amount of additive being in the range from 5% to 50% by weight, based on the monomers, and the weight ratio of the first portion to the second portion of the additive being in the range from 10:1 to 1:5. The resin powder is recycled fine-sized material for example. Not only the residual monomer content, specifically the residual crosslinker content, but also the level of extractables in the water-absorbing resin are reduced by the method of addition described. A high fraction of additives can be incorporated without the properties of the water-absorbing resin obtained being adversely affected. The additives enter a sufficiently firm bond with the resin, so that no excessive dusting occurs on exposure to mechanical stress.

Production of a water-absorbing resin to which a particulate additive is admixed

The invention relates to a method for monitoring the bending of a shaft, particularly a shaft in a mixing kneader, the shaft having a bearing at least on one side. In a first step, the deviation of the shaft from the radial position is measured on at least one position different from the bearing of the shaft. In a further step, a reference value is optionally determined from the measured deviation from the radial position. In a third step, the deviation from the radial position as measured in the first step or the reference value found in the second step is compared with a predetermined limit value.

Method for avoiding overloading of a shaft

Use of an apparatus for adding at least one additive to a reactor interior

Method for producing post-cured water-absorbent polymer particles with a higher absorption by polymerising droplets of a monomer solution

A process for preparing water-absorbing polymer beads with high permeability by polymerizing droplets of a monomer solution in a gas phase surrounding the droplets, wherein the monomer solution comprises at least 0.5% by weight of a crosslinker, based on the monomer, the polymerization in the droplet takes place in homogeneous phase, and the polymer beads have a mean diameter of at least 150 &#x3bc;m.

The invention relates to a mixing kneader comprising at least two shafts () configured as hollow shafts, on whose surfaces kneading bars () are disposed on elements (). The construction of the shafts is selected in such a way that the resonant frequencies of the shafts have a separation of at least 5% from the excitation frequencies. At least one of the shafts is preferably flowed through by a temperature-control medium, the inlet being disposed on one side and the outlet on the other side of the shaft. The mixing kneader preferably comprises at least one orifice above the shafts which is configured as a dome, the dome being closed by a displacer (). In addition, at least one orifice for product withdrawal is provided, whose orifice cross section is adjustable during operation.

Mixing kneader and process for preparing poly(meth)acrylates using the mixing kneader

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Künzell, Germany

Annemarie Hillebrecht