The Dow Chemical Company

Evonik Stockhausen Gmbh

Dow Global Technolgoies LLC

Evonik Degussa Gmbh

Herbert A Gartner

Marc Hager

Hans-Peter Kohler

Daniel Fricker

Jorg Harren

Harald Plochinger

Harald Plöchinger

Jörg Harren

Sabine Auernig

Christopher John Tucker

John Klier

Andrew T Graham

Steven W Mork

Reed A Shick

Heike Herr

Josef H Burgert

Thomas L Staples

Fredric L Buchholz

Stephen B Christensen

Thomas C Johnson

Michael A Fialkowski

Elisabeth Lacker

Philippe Trijasson, Deceased

Roswitha Petri

Katrin Nuyken

Deno F O'Connor

The present invention relates to a method for heat-treating water-absorbing polymeric particles at a temperature equal to or above 150&#xb0; C. in a fluidized bed dryer at a fast heat-up rate, the use of a fluidized bed dryer for heat-treating water-absorbing polymeric particles in continuous or batch mode as well as to the heat-treated polymeric particles obtained by the method of the present invention.

Heat-treatment of water-absorbing polymeric particles in a fluidized bed at a fast heat-up rate

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.

Superabsorbent polymer process

Continuous process for the production of a superabsorbent polymer

The present invention relates to superabsorbent polymer comprising the comprising the free radical polymerization product of an aqueous monomer mixture containing at least one &#x3b1;,&#x3b2;-ethylenically unsaturated monomer; at least one monomer having at least two &#x3b1;,&#x3b2;-ethylenically unsaturated groups; a crosslinking agent having at least two polymerizable double bonds; iron ions in an amount of from about 0.1 to about 3 wppm based on the total weight of the aqueous monomer mixture; and at least one chelating agent in an amount to provide a molar ratio of chelating agent to iron ion of from about 0.8 to about 4.0.

Process for the production of a superabsorbent polymer

The present invention relates to process for the preparation of a superabsorbent polymer comprising the steps of a) subjecting an aqueous monomer mixture containing at least one &#x3b1;,&#x3b2;-ethylenically unsaturated monomer; at least one monomer bearing at least two &#x3b1;,&#x3b2;-ethylenically unsaturated groups; iron ions in an amount of 0.1 to 3 wppm based on the total weight of the aqueous monomer mixture; and at least one chelating agent in an amount to provide a mol ratio of chelating agent to iron ion of 0.8 to 4.0 to free radical polymerization in an reactor to obtain a super-absorbent polymer; and b) recovering the superabsorbent polymer, whereby if the process is continuous and is run in an agitated reactor the upper limit of the mol ratio of chelating agent to iron ion is 4.0 for a throughput of total reaction mixture through the reactor of at most 1.3 kg/h per liter reactor volume.

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.

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.

A continuous process for producing water-insoluble, water-swellable polymers comprises subjecting a monomer and initiator to polymerization conditions in a reactor system having at least 3 zones.

Continuous polymerization process for the manufacture of superabsorbent polymers

The present invention refers to a high internal phase polyelectrolyte emulsions which are useful for the manufacture of superabsorbent polymers having two phases: i) a continuous oil phase and the ii) a dispersed aqueous phase containing the aqueous monomer solution prior to polymerization and the polyelectrolyte in water-soluble, or water-swellable or very slightly crosslinked form after polymerization, wherein the polymerization occurs in the dispersed aqueous phase and wherein the dispersed aqueous phase contains a high concentration of polyelectrolyte. The present invention also refers to a process for preparing such emulsions and for inverting these emulsions so as to form films or other patterns of the superabsorbent polymer. Absorbent structures containing SAP films or other patterns prepared by the present invention are also contemplated.

High internal phase polyelectrolyte emulsions for the manufacture of superabsorbent polymers and superabsorbent polymers made therefrom

The present invention refers to a high internal phase polyclectrolyte emulsions which are useful for the manufacture of superabsorbent polymers having two phases: i) a continuous oil phase and the ii) a dispersed aqueous phase containing the aqueous monomer solution prior to polymerization and the polyelectrolyte in water-soluble, or water-swellable or very slightly crosslinked form after polymerization, wherein the polymerization occurs in the dispersed aqueous phase and wherein the dispersed aqueous phase contains a high concentration of polyclectrolyte. The present invention also refers to a process for preparing such emulsions and for inverting these emulsions so as to form films or other patterns of the superabsorbent polymer. Absorbent structures containing SAP films or other patterns prepared by the present invention are also contemplated.

Manufacture of superabsorbents in high internal phase emulsions

A composition comprising aqueous fluid absorbent polymer particles which have been heat-treated at temperatures greater than 170&deg; C. for more than 10 minutes, wherein the composition has been remoisturized, after the heat-treatment, with an aqueous additive solution, in the absence of an organic solvent or water-insoluble, non-swellable powder, and comprises 1 to 10 percent by weight, based on the total weight of the composition, water and wherein the composition is characterized by the ability to absorb at least 20 grams of a 0.9 weight percent aqueous saline solution under a pressure of 0.3 psi (21,000 dynes/cm,), that is, a 60 minute 0.3 psi (21,000 dynes/cm,) AUL greater than 20 grams/gram. A process for preparing such a composition.

Superabsorbent polymers having improved processability

The invention is surface crosslinked particles of water absorbing resin comprising particles of a carboxyl containing water-absorbent resin; wherein the particles of the carboxyl containing water-absorbent resin are crosslinked at or near the particle surface by a polyhydroxy compound capable of reacting with the carboxyl moieties of the water-absorbent resin, and the particles have coated on or bound to the surface a nonionic surfactant having an HLB of from 3 to 10. Additionally a process for the preparation of such surface crosslinked and surfactant coated absorbent resin particles is disclosed. Further disclosed is a water-absorbent structure comprising a synthetic or natural fiber or paper based woven or nonwoven carrier structure and surface crosslinked and surfactant coated water-absorbent resin particles of this invention.

Surface crosslinked and surfactant coated absorbent resin particles and

Water absorbent resin particles of crosslinked carboxyl containing

The invention is crosslinked carboxyl containing hydrophilic resin crosslinked by a compound corresponding to formula 1,

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Baden-Baden, Germany

Herbert A Gartner