Abstract: An apparatus for producing pulverulent poly(meth)acrylate in a reactor for droplet polymerization having an apparatus for dropletization of a monomer solution for the production of the poly(meth)acrylate having holes through which the monomer solution is introduced, an addition point for a gas above the apparatus for dropletization, at least one gas withdrawal point on the circumference of the reactor and a fluidized bed, and above the gas withdrawal point the reactor has a region having a constant hydraulic internal diameter and below the gas withdrawal point the reactor has a hydraulic internal diameter that steadily decreases. The reactor has a heating means in the region having a steadily decreasing hydraulic internal diameter.

Abstract: An apparatus for addition of droplets of a monomer solution for production of poly(meth)acrylate to a reactor for droplet polymerization, comprising at least one channel or a dropletizer head having, at its base, holes through which the solution is dropletized into the reactor, at least one of the following features being fulfilled: (a) the ratio of the area covered by the channels or the dropletizer head in the reactor relative to the area which is defined by the circumference of a line along the outermost holes is less than 50%, (b) the number of holes relative to the area which is defined by the circumference of a line along the outermost holes is within a range from 100 to 1000 holes/m2.

Abstract: The invention relates to an apparatus for producing pulverulent poly(meth)acrylate, comprising a reactor for droplet polymerization having an apparatus for dropletization of a monomer solution for the preparation of the poly(meth)acrylate having holes through which the monomer solution is introduced, an addition point for a gas above the apparatus for dropletization, at least one gas withdrawal point on the circumference of the reactor and a fluidized bed, the reactor comprising a reactor shell between the apparatus for dropletization and the gas withdrawal point and having, above the fluidized bed, a region having decreasing hydraulic diameter toward the fluidized bed and having a maximum hydraulic diameter greater than the mean hydraulic diameter of the reactor shell, and the reactor shell projecting into the region having decreasing hydraulic diameter, so as to form an annular duct between the outer wall of the reactor shell and the wall by which the region having decreasing hydraulic diameter is bounded,

Abstract: The present invention relates to a process for producing water-absorbent polymer particles by polymerizing droplets of a monomer solution comprising less than 0.3% by weight of persulfate and at least 0.05% by weight of azo initiator and thermal aftertreatment of the formed polymer particles at less than 100° C. in a fluidized bed for 60 to 300 minutes.

Abstract: An apparatus for introducing droplets of a monomer solution for production of poly(meth)acrylate into a reactor for droplet polymerization, comprising at least one channel or a dropletizer head, the channel or the dropletizer head being sealed at its base by a dropletizer plate, the dropletizer plate having holes through which the monomer solution is introduced into the reactor, and the dropletizer plate being configured such that holes that, in an axially symmetric dropletizer plate or in an annular dropletizer plate or in one configured as a ring segment, are not on a center line of the dropletizer plate or, in the case of a circular dropletizer plate, are not at the center of the dropletizer plate are aligned such that monomer solution is introduced through the holes into the reactor at an angle to the vertical, and the holes in the case of a radial alignment of axially symmetric dropletizer plates being aligned such that the angle at which the monomer solution is introduced into the reactor decreases in t

Abstract: The present invention relates to a process for producing water-absorbent polymer particles by polymerizing droplets of a monomer solution in a surrounding heated gas phase in a reactor comprising a gas distributor (3), a reaction zone (5) and a fluidized bed (27), the gas leaving the reactor is treated in a condenser column (12) with an aqueous solution, the treated gas leaving the condenser column (12) is recycled at least partly to the fluidized bed (27), wherein the gas leaving the condenser column (12) comprises from 0.05 to 0.3 kg steam per kg dry gas and the steam content of the gas entering the gas distributor (3) is less than 80% of the steam content of the gas leaving the condenser column (12).

Abstract: An apparatus for producing pulverulent poly(meth)acrylate in a reactor for droplet polymerization having an apparatus for dropletization of a monomer solution for the production of the poly(meth)acrylate having holes through which the monomer solution is introduced, an addition point for a gas above the apparatus for dropletization, at least one gas withdrawal point on the circumference of the reactor and a fluidized bed, and above the gas withdrawal point the reactor has a region having a constant hydraulic internal diameter and below the gas withdrawal point the reactor has a hydraulic internal diameter that steadily decreases. The reactor has a heating means in the region having a steadily decreasing hydraulic internal diameter.

Abstract: An apparatus for producing pulverulent poly(meth)acrylate in a reactor for droplet polymerization having an apparatus for dropletization of a monomer solution for the production of the poly(meth)acrylate having holes through which the monomer solution is introduced, an addition point for a gas above the apparatus for dropletization, at least one gas withdrawal point on the circumference of the reactor and a fluidized bed, and above the gas withdrawal point the reactor has a region having a constant hydraulic internal diameter and below the gas withdrawal point the reactor has a hydraulic internal diameter that steadily decreases.

Abstract: The present invention relates to a process for producing water-absorbent polymer particles by polymerizing droplets of a monomer solution comprising less than 0.3% by weight of persulfate and at least 0.05% by weight of azo initiator and thermal aftertreatment of the formed polymer particles at less than 100° C. in a fluidized bed for 60 to 300 minutes.

Abstract: The present invention relates to a process for producing water-absorbent polymer particles by polymerizing droplets of a monomer solution comprising less than 0.3% by weight of persulfate and at least 0.05% by weight of azo initiator and thermal aftertreatment of the formed polymer particles at less than 100° C. in a fluidized bed for 60 to 300 minutes.

Abstract: An apparatus for production of pulverulent poly(meth)acrylate, comprising a reactor or droplet polymerization, having an apparatus for dropletization of a monomer solution for the production of the poly(meth)acrylate, having holes through which the solution is dropletized, an addition point for a gas above the apparatus for dropletization, at least one gas withdrawal point on the periphery of the reactor and a fluidized bed. The outermost holes through which the solution is dropletized are positioned such that a droplet falling vertically downward falls into the fluidized bed and the hydraulic diameter at the level of the midpoint between the apparatus for dropletization and the gas withdrawal point is at least 10% greater than the hydraulic diameter of the fluidized bed.

Abstract: An apparatus for introducing droplets of a monomer solution for production of poly(meth)acrylate into a reactor for droplet polymerization, comprising at least one channel or a dropletizer head, the channel or the dropletizer head being sealed at its base by a dropletizer plate, the dropletizer plate having holes through which the monomer solution is introduced into the reactor, and the dropletizer plate being configured such that holes that, in an axially symmetric dropletizer plate or in an annular dropletizer plate or in one configured as a ring segment, are not on a center line of the dropletizer plate or, in the case of a circular dropletizer plate, are not at the center of the dropletizer plate are aligned such that monomer solution is introduced through the holes into the reactor at an angle to the vertical, and the holes in the case of a radial alignment of axially symmetric dropletizer plates being aligned such that the angle at which the monomer solution is introduced into the reactor decreases in t

Abstract: An apparatus for addition of droplets of a monomer solution for production of poly(meth)acrylate to a reactor for droplet polymerization, comprising at least one channel or a dropletizer head having, at its base, holes through which the solution is dropletized into the reactor, at least one of the following features being fulfilled: (a) the ratio of the area covered by the channels or the dropletizer head in the reactor relative to the area which is defined by the circumference of a line along the outermost holes is less than 50%, (b) the number of holes relative to the area which is defined by the circumference of a line along the outermost holes is within a range from 100 to 1000 holes/m2.

Abstract: The present invention relates to a process for producing water-absorbent polymer particles by polymerizing droplets of a monomer solution in a surrounding heated gas phase in a reactor comprising a gas distributor (3), a reaction zone (5) and a fluidized bed (27), the gas leaving the reactor is treated in a condenser column (12) with an aqueous solution, the treated gas leaving the condenser column (12) is recycled at least partly to the fluidized bed (27), wherein the gas leaving the condenser column (12) comprises from 0.05 to 0.3 kg steam per kg dry gas and the steam content of the gas entering the gas distributor (3) is less than 80% of the steam content of the gas leaving the condenser column (12).

Abstract: The present invention relates to a process for producing water-absorbent polymer particles by polymerizing droplets of a monomer solution comprising less than 0.3% by weight of persulfate and at least 0.05% by weight of azo initiator and thermal aftertreatment of the formed polymer particles at less than 100° C. in a fluidized bed for 60 to 300 minutes.

Abstract: Hydrogel particles are produced by a drying step followed sequentially by precomminuting, grinding, separating, and further drying of coarse particles.

Abstract: Water-swellable hydrophilic polymers are prepared by neutralization of the acidic hydrogel having a degree of neutralization of 0-40 mol % to an ultimate degree of neutralization of 60-85 mol % by mixing with a neutralizing agent in a mincer comprising a system of screw, rotating blade, restricted flow zone and breaker plate, wherein the mincer has a power output of from 1000 to 6000 Wh/m3 the hydrogel passes through a zone having-an energy dissipation density of from 400 to 800 W/1 of mixing volume the average residence time of the hydrogel in the mincer is from 5 to 30 seconds the breaker plate has an open area of from 20 to 40%.