Abstract: The invention relates generally to a process for the preparation of water-absorbent polymer particles, including the process steps of preparing particulate water-absorbent polymer and mixing the particulate water-absorbent polymer with an aqueous crosslinker solution and heat-treating the mixture of particulate water-absorbent polymer in a horizontally operated mixing device, wherein the horizontally operated mixing device is hydraulically driven. The invention also relates to water-absorbent polymer particles obtainable by such a process.

Abstract: The present invention relates to a continuous process for the production of a superabsorbent polymer comprising providing an acidic liquid aqueous monomer mixture containing dissolved oxygen; continuously feeding the aqueous monomer mixture to a reactor; introducing a source of carbonate or hydrogen carbonate into the aqueous monomer mixture prior to entry into the reactor thereby forming a gas phase comprising carbon dioxide and at least a part of the dissolved oxygen, the gas phase being dispersed in the liquid phase; subjecting the gas/liquid mixture to at least partial phase separation immediately prior to or after entry into the reactor and at least partially removing the separated gaseous phase; subjecting the liquid phase in the reactor to free-radical polymerization to obtain the superabsorbent polymer, and continuously removing the superabsorbent polymer from the reactor.

Abstract: The present invention relates to a continuous process for the production of a superabsorbent polymer comprising providing an acidic liquid aqueous monomer mixture containing dissolved oxygen; continuously feeding the aqueous monomer mixture to a reactor; introducing a source of carbonate or hydrogen carbonate into the aqueous monomer mixture prior to entry into the reactor thereby forming a gas phase comprising carbon dioxide and at least a part of the dissolved oxygen, the gas phase being dispersed in the liquid phase; subjecting the gas/liquid mixture to at least partial phase separation immediately prior to or after entry into the reactor and at least partially removing the separated gaseous phase; subjecting the liquid phase in the reactor to free-radical polymerization to obtain the superabsorbent polymer, and continuously removing the superabsorbent polymer from the reactor.

Abstract: The present invention relates to a continuous process for the production of a superabsorbent polymer comprising providing an acidic liquid aqueous monomer mixture containing dissolved oxygen; continuously feeding the aqueous monomer mixture to a reactor; introducing a source of carbonate or hydrogen carbonate into the aqueous monomer mixture prior to entry into the reactor thereby forming a gas phase comprising carbon dioxide and at least a part of the dissolved oxygen, the gas phase being dispersed in the liquid phase; subjecting the gas/liquid mixture to at least partial phase separation immediately prior to or after entry into the reactor and at least partially removing the separated gaseous phase; subjecting the liquid phase in the reactor to free-radical polymerization to obtain the superabsorbent polymer, and continuously removing the superabsorbent polymer from the reactor.

Abstract: The present invention relates to a process for the production of a superabsorbent polymer comprising preparing an aqueous mixture of monomers selected to provide after polymerization a superabsorbent polymer; feeding said monomer mixture to a reactor; subjecting the aqueous monomer mixture in the reactor to free-radical polymerization to obtain a superabsorbent polymer gel; removing the superabsorbent polymer gel from the reactor; and drying the superabsorbent polymer gel. Where at least one off-gas stream removed from any stage of the process is subjected to scrubbing with a basic aqueous solution prior to venting to obtain an aqueous scrubber solution that is at least partially recycled to any of the above steps of the process.

Abstract: The present invention relates to a process for the production of a superabsorbent polymer comprising preparing an aqueous mixture of monomers selected to provide after polymerization a superabsorbent polymer; feeding said monomer mixture to a reactor; subjecting the aqueous monomer mixture in the reactor to free-radical polymerization to obtain a superabsorbent polymer gel; removing the superabsorbent polymer from the reactor; and working-up the superabsorbent polymer removed from the reactor to obtain a final product, whereby a basic aqueous medium comprising carbonate and/or hydrogen carbonate is fed to the superabsorbent polymer gel.

Abstract: The present invention relates to a continuous process for the production of a superabsorbent polymer comprising providing an acidic liquid aqueous monomer mixture containing dissolved oxygen; continuously feeding the aqueous monomer mixture to a reactor; introducing a source of carbonate or hydrogen carbonate into the aqueous monomer mixture prior to entry into the reactor thereby forming a gas phase comprising carbon dioxide and at least a part of the dissolved oxygen, the gas phase being dispersed in the liquid phase; subjecting the gas/liquid mixture to at least partial phase separation immediately prior to or after entry into the reactor and at least partially removing the separated gaseous phase; subjecting the liquid phase in the reactor to free-radical polymerization to obtain the superabsorbent polymer, and continuously removing the superabsorbent polymer from the reactor.

Abstract: The present invention relates to a process for the production of a superabsorbent polymer comprising preparing an aqueous mixture of monomers selected to provide after polymerization a superabsorbent polymer; feeding said monomer mixture to a reactor; subjecting the aqueous monomer mixture in the reactor to free-radical polymerization to obtain a superabsorbent polymer gel; removing the superabsorbent polymer gel from the reactor; and drying the superabsorbent polymer gel. Where at least one off-gas stream removed from any stage of the process is subjected to scrubbing with a basic aqueous solution prior to venting to obtain an aqueous scrubber solution that is at least partially recycled to any of the above steps of the process.

Abstract: The present invention relates to a process for the production of a superabsorbent polymer comprising preparing an aqueous mixture of monomers selected to provide after polymerization a superabsorbent polymer; feeding said monomer mixture to a reactor; subjecting the aqueous monomer mixture in the reactor to free-radical polymerization to obtain a superabsorbent polymer gel; removing the superabsorbent polymer from the reactor; and working-up the superabsorbent polymer removed from the reactor to obtain a final product, whereby a basic aqueous medium comprising carbonate and/or hydrogen carbonate is fed to the superabsorbent polymer gel.