Abstract:
The invention relates to a method for producing water-absorbent polymer particles with a higher permeability by polymerising droplets of a monomer solution, containing monomers with acid groups, in a gas phase surrounding the droplets. The monomer solution contains polyvalent cations and the polymer particles have an average diameter of at least 150 µm.
Abstract:
The invention relates to a use of a device for addition of at lest one solid, highly viscous, or solvent-dispersed additive into a reactor for the production of cross-linked fine-particulate polymers by copolymerisation of (a) water-soluble, monoethylenically-unsaturated monomers and (b) 0.001 to 5 mol. %, based on monomers (a), of at least two polymerisable groups containing monomers, (c) 0 to 20 mol. %, based on monomers (a), of water-insoluble monoethylenically-unsaturated monomers. Said device comprises at least one screw for the supply of the at least one additive and the at least one screw terminates in an addition opening essentially flush with the reactor inner wall.
Abstract:
A coating process where, in a horizontal mixer, an aqueous liquid is sprayed onto surface-post-crosslinked water absorbent polymer particles, and the horizontal-mixer inner wall in contact with the product is made of stainless steel.
Abstract:
The invention relates to a method for producing water-absorbent polymer particles by the polymerisation of droplets of a monomer solution in a gaseous phase that surrounds said droplets and by the subsequent cross-linking of the polymer particles. According to the invention, the polymer particles that have been subsequently cross-linked are at least partially coated.
Abstract:
Method for thermal post-crosslinking of the surface of water-absorbing polymer particles in a fluidized layer produced using a carrier gas, wherein the surface post-crosslinking means is fed to the fluidized layer in gaseous form.
Abstract:
The invention relates to a method for producing water-absorbent polymer particles by the polymerisation of droplets of a monomer solution in a gaseous phase that surrounds said droplets. According to the invention, the particle surface is at least partially coated with at least one polymer and/or wax.