Patent ID: 8529805
Filing Date: 2013-09-10
Classification: A61L,B29B,C08F,Y10T

Abstract:
1. A process for preparing water-absorbing polymer beads comprising (a) providing a first monomer solution comprising (b) providing a second monomer solution comprising (c) forming droplets in a surrounding gas phase, the droplets obtained by enveloping the first monomer solution with the second monomer solution by metering the first monomer solution into the gas phase through at least one bore and a pressure drop through the bore is less than 2.5 bar, and metering the second monomer solution in through an annular gap which surrounds a feed of the first monomer solution; and (d) polymerizing the droplets formed in (c) in the surrounding gas phase to provide water-absorbing polymer beads having a crosslinking gradient wherein the enveloping second monomer solution polymerizes to give a more highly crosslinked polymer than the polymerized enveloped first polymer solution.