Abstract: 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 ?m.

Abstract: 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 ?m.

Abstract: 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 ?m.

Abstract: 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 (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, where the apparatus comprises at least one screw for conveying the at least one additive and the at least one screw ends in an addition orifice substantially flush with the inner wall of the reactor interior.

Abstract: 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.

Abstract: 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 ?m.

Abstract: 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 ?m.

Abstract: 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.

Abstract: 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.

Abstract: 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 (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, where the apparatus comprises at least one screw for conveying the at least one additive and the at least one screw ends in an addition orifice substantially flush with the inner wall of the reactor interior.

Abstract: 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 (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, where the apparatus comprises at least one screw for conveying the at least one additive and the at least one screw ends in an addition orifice substantially flush with the inner wall of the reactor interior.

Abstract: 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 ?m.

Abstract: 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 ?m.

Abstract: The invention relates to a mixing kneader comprising at least two shafts (2,3) configured as hollow shafts, on whose surfaces kneading bars (4) are disposed on elements (5). 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 (22). In addition, at least one orifice for product withdrawal is provided, whose orifice cross section is adjustable during operation.

Abstract: 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 ?m.

Abstract: The invention relates to a mixing kneader comprising at least two shafts (2,3) configured as hollow shafts, on whose surfaces kneading bars (4) are disposed on elements (5). 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 (22). In addition, at least one orifice for product withdrawal is provided, whose orifice cross section is adjustable during operation.

Abstract: Superabsorbents are produced by polymerisation in a kneader equipped with at least two parallel shafts that also comprises elements on at least one shaft that transport the kneader's content parallel to the shafts from a feed section to a discharge section, the process comprising the addition of an inorganic powder to the kneader's contents prior to or during polymerisation and the addition of at least one other additive to the kneader's contents during polymerisation, wherein the inorganic powder is added no later than half the average residence time of the kneader's contents and the other additive is added no earlier than half this residence time.

Abstract: 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.

Abstract: 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.

Abstract: 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.