Abstract: The invention relates to a classification process for superabsorbent polymer particles, comprising classifying the water-absorbent polymer particles in a screen machine under reduced pressure wherein the pressure above the uppermost sieve is from 0 to 4.0 mbar per sieve higher than below the undermost sieve.

Abstract: The invention relates to a belt drier arrangement for drying an aqueous polymer gel and for comminuting the dried polymer gel to give dried polymer particles, comprising: a drier setup for drying an aqueous polymer gel, a comminuting arrangement downstream of the drier setup relative to the product flow direction, for comminuting the dried polymer gel to give dried polymer particles. In accordance with the invention the comminuting arrangement comprises at least a first comminutor and a second comminutor, each having a rotatable shaft with functional tools, the second comminutor being disposed downstream of the first comminutor relative to the product flow direction.

Abstract: A method for the classification of superabsorber particles is disclosed, in which the superabsorber particles are put onto a top screen deck of a screening machine having at least two screen decks with a different hole size, the superabsorber particles which are smaller than the holes of the respective screen deck respectively falling through the holes and the superabsorber particles remaining on the screen deck being removed via an extraction point. Balls are positioned on each perforated plate, which balls are propelled upward by the movement of the perforated plate and strike from below the screen deck respectively lying above, wherein the balls have a stiffness in the range from 40 to 100 N/mm and a damping in the range from 1 to 4%. A machine for carrying out the method also is disclosed.

Abstract: The invention relates to a belt drier arrangement for drying an aqueous polymer gel and for comminuting the dried polymer gel to give dried polymer particles, comprising: a drier setup for drying an aqueous polymer gel, a comminuting arrangement downstream of the drier setup relative to the product flow direction, for comminuting the dried polymer gel to give dried polymer particles. In accordance with the invention the comminuting arrangement comprises at least a first comminutor and a second comminutor, each having a rotatable shaft with functional tools, the second comminutor being disposed downstream of the first comminutor relative to the product flow direction.

Abstract: The invention relates to a process for producing superabsorbent polymer particles, comprising surface postcrosslinking, classifying the surface postcrosslinked superabsorbent polymer particles, deagglomerating the separated oversize fraction using a roll crusher and recycling the disintegrated oversize fraction before or into the classification of the surface postcrosslinked superabsorbent polymer particles.

Abstract: The invention relates to a classification process for superabsorbent polymer particles, comprising classifying the water-absorbent polymer particles in a screen machine under reduced pressure wherein the pressure above the uppermost sieve is from 0 to 4.0 mbar per sieve higher than below the undermost sieve.

Abstract: A production process for production of water absorbing polymer particles, including drying an aqueous polymer gel in a belt drier with a conveyor belt having a drier setup in the interior, in which drying air in the interior of the drier setup is conducted in countercurrent counter to the conveying direction and the interior of the drier setup is kept substantially at a reduced pressure relative to the ambient pressure outside the drier setup, and the interior has and/or forms a pressure zone, and is especially divided into a number of pressure zones.

Abstract: A production process for production of water-absorbing polymer particles including drying an aqueous polymer gel in a belt drier with a conveyor belt. The belt drier is formed with a drier setup substantially comprising the conveyor belt and an air recycling conduit downstream of the drier setup for air recycling, where recycled air is withdrawn from the drier setup and fed back to the drier setup via the air recycling conduit.

Abstract: Filling process for superabsorbent polymer particles The invention relates to a filling process for superabsorbent polymer particles, comprising discharging the superabsorbent polymer particles out of a silo into bulk container for shipping, wherein the filling level of the silo during filling of the bulk container is never less than 20%, in order to avoid particle segregation.

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: The invention relates to a process for producing water-absorbing polymer particles, comprising the steps of: •—processing an aqueous polymer gel from polymerization of a monomer solution or suspension, •—drying the aqueous polymer gel in a conveyer dryer, in particular in a forced air conveyer dryer, wherein •—the conveyer dryer has a circulating conveyer belt and the aqueous polymer gel is conveyed on the circulating conveyer belt, and wherein •—the circulating conveyer belt is formed as a circulating plate conveyer belt, comprising a number of belt plates separated by a hinge line of a hinge assembly and each belt plate having a surface for receiving the aqueous polymer gel, wherein said hinge assembly comprises a knuckle joint (301) with the hinge line in form of a straight hinge line.

Abstract: A process for producing water-absorbing polymer particles, wherein surface postcrosslinked water-absorbing polymer particles are remoisturized and delivered pneumatically, and wherein the time between remoisturization and pneumatic delivery is less than one hour.

Abstract: A method for the classification of superabsorber particles is disclosed, in which the superabsorber particles are put onto a top screen deck of a screening machine having at least two screen decks with a different hole size, the superabsorber particles which are smaller than the holes of the respective screen deck respectively falling through the holes and the superabsorber particles remaining on the screen deck being removed via an extraction point. Balls are positioned on each perforated plate, which balls are propelled upward by the movement of the perforated plate and strike from below the screen deck respectively lying above, wherein the balls have a stiffness in the range from 40 to 100 N/mm and a damping in the range from 1 to 4%. A machine for carrying out the method also is disclosed.

Abstract: The invention relates to a process for producing water-absorbing polymer particles, comprising the steps of: •—processing an aqueous polymer gel from polymerization of a monomer solution or suspension, •—drying the aqueous polymer gel in a conveyer dryer, in particular in a forced air conveyer dryer, wherein •—the conveyer dryer has a circulating conveyer belt and the aqueous polymer gel is conveyed on the circulating conveyer belt, and wherein •—the circulating conveyer belt is formed as a circulating plate conveyer belt, comprising a number of belt plates separated by a hinge line of a hinge assembly and each belt plate having a surface for receiving the aqueous polymer gel, wherein said hinge assembly comprises a knuckle joint (301) with the hinge line in form of a straight hinge line.

Abstract: The invention relates to a process for producing water-absorbing polymer particles, comprising the steps of: •—processing an aqueous polymer gel from polymerization of a monomer solution or suspension, •—drying the aqueous polymer gel in a conveyer dryer, in particular in a forced air conveyer dryer, wherein •—the conveyer dryer has a circulating conveyer belt and the aqueous polymer gel is conveyed on the circulating conveyer belt, and wherein •—the circulating conveyer belt is formed as a circulating plate conveyer belt, comprising a number of belt plates separated by a hinge line of a hinge assembly and each belt plate having a surface for receiving the aqueous polymer gel, wherein said hinge assembly comprises a knuckle joint (301) with the hinge line in form of a straight hinge line.

Abstract: A production process for production of water-absorbing polymer particles including drying an aqueous polymer gel in a belt drier with a conveyor belt. The belt drier is formed with a drier setup substantially comprising the conveyor belt and an air recycling conduit downstream of the drier setup for air recycling, where recycled air is withdrawn from the drier setup and fed back to the drier setup via the air recycling conduit.

Abstract: A production process for production of water absorbing polymer particles, including drying an aqueous polymer gel in a belt drier with a conveyor belt having a drier setup in the interior, in which drying air in the interior of the drier setup is conducted in countercurrent counter to the conveying direction and the interior of the drier setup is kept substantially at a reduced pressure relative to the ambient pressure outside the drier setup, and the interior has and/or forms a pressure zone, and is especially divided into a number of pressure zones.

Abstract: The present invention relates to an apparatus for producing water-absorbing polymer particles by polymerizing monomers on a continuous conveyor belt, wherein joins of the conveyor belt and/or damage on the conveyor belt surface have been sealed with a sealing composition.

Abstract: The invention relates to the production of superabsorbent polymers on a continuous belt reactor, comprising at least one rotating knife that cuts the formed polymer gel at the end of the continuous belt reactor, wherein the length of the cutting edge is at least 1 cm and the cutting edge is non-parallel to the rotation axis.

Abstract: A process for producing water-absorbing polymer particles, comprising the steps of thermal cracking of bionaphtha in the presence of steam, removing propene and at least some of the propane, gas phase oxidation to give acrylic acid and polymerization to give water-absorbing polymer particles.