Basf Se Corporation

Monica Haag

Stephan Deuerlein

Volker Klock

Roland Krauss

Mubarik Mahmood Chowdhry

Markus Braun

Holger Barthel

Matthias Weismantel

Stefan Mecking

Thomas Gieger

Jacob Wildeson

Xavier Sava

Ulrich Nieken

Ludmila Kolb

Stefan Gierescher

A process for producing superabsorbent particles, comprising polymerization of a monomer preparation, drying of the resultant aqueous polymer gel, grinding, classifying and thermal surface postcrosslinking, wherein the monomer preparation is produced by mixing an aqueous monomer solution and a foamed aqueous surfactant solution.

Method for producing superabsorbent particles

A single-screw extruder for changing a morphology of superabsorbent polymer gel. The single-screw extruder has an input aperture, a channel, a screw and an output aperture. The screw in the invention has a first pitch value of a pitch of the screw flights along the conveying zone of the channel and, following in conveying direction, has a second pitch value of the pitch of the screw flights along the conveying zone of the channel, where the second pitch value is smaller than the first pitch value.

Single-shaft extruder and use of a single-shaft extruder, and method for altering morphology of a superabsorbent polymer, specifically an SAP polymer gel, using a single-shaft extruder

A single-screw extruder for changing a morphology of a superabsorbent polymer, specifically a polymer gel. The single-screw extruder has an input aperture, a channel, a screw and an output aperture. The screw has a pitch value of a pitch of the screw flights along the conveying zone of the channel, where the channel has a mixing-element arrangement with at least one mixing element which protrudes into the channel of the single-screw extruder and which is configured for the mixing of the SAP polymer gel.

Single-shaft extruder and use of a single-shaft extruder, and method for altering morphology of a superabsorbent polymer gel using a single-shaft extruder

A process for producing water-absorbing polymer particles is provided, comprising a) a polymerization step in which an aqueous monomer solution comprising at least one ethylenically unsaturated monomer M which bears acid groups and may have been at least partly neutralized and at least one crosslinker is polymerized to obtain an aqueous polymer gel; b) a pelletization step in which the aqueous polymer gel having a solids content of 35 to 70% by weight and a temperature of 75 to 125&#xb0; C. is forced from a high-pressure zone through a die plate into a low-pressure zone and pellets are obtained, the pressure differential between the high-pressure zone and the low-pressure zone being 4 to less than 14 bar and the orifice ratio of the die plate being 30 to 80%; c) a drying step in which the pellets are dried to a moisture content of less than 10% by weight; d) a grinding step and a classifying step to obtain water-absorbing polymer particles; and e) surface crosslinking of the water-absorbing polymer particles. The water-absorbing polymer particles have a high swell rate and a high retention capacity combined with a favorable ratio of permeability of the swollen gel bed SFC to centrifuge retention capacity CRC.

Method for producing water-absorbing polymer particles

Crosslinked polymer particles having a) a proportion of particles having a particle size of 150 to 300 &#x3bc;m of at least 20% by weight, b) a free swell rate of the entirety of the polymer particles FSRof at least 0.25 g/g&#xb7;s, c) a difference &#x394;FSR of at least 0.15, d) a centrifuge retention capacity CRC of at least 25.0 g/g, and e) a permeability of the swollen gel bed SFC of at least 90&#xd7;10cm&#xb7;s/g are disclosed.

Water-absorbing polymer particles

A process for producing water-absorbing polymer particles having high free swell rate and high centrifuge retention capacity with simultaneously high permeability of the swollen gel bed by polymerization of an aqueous monomer solution in a polymerization reactor having at least two shafts (kneaders) which rotate in an axially parallel manner, subsequent extrusion at high temperatures and thermal surface postcrosslinking.

Method for producing water-absorbing polymer particles with high swelling rate and high centrifuge retention capacity with simultaneously high permeability of the swollen gel bed

An aqueous polymer dispersion is prepared by reacting at least one olefin in the presence of at least one polymerization catalyst and one emulsifier in an aqueous medium by a process wherein the polymerization catalyst is prepared in an in situ reaction by reacting the ligand compound 2,6-dichloro-para-benzoquinone (Ia) and/or 2,3,6-trichloro-para-benzoquinone (Ib) with a phosphine compound or diphosphine compound and with a metal compound and the polymerization reaction is effected in an aqueous medium.

Method for emulsion polymerizing olefins

Process for the emulsion polymerization of one or more olefins by reacting a quinoid compound with a metal compound and a phosphine compound which is substituted by at least one polar radical and subsequently using the reaction product for the polymerization or copolymerization of olefins in water or in a solvent mixture which contains at least 50% by weight of water and at least one emulsifier.

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Ludwigshafen, Germany

Monica Haag