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US 6,987,151 B2Granted
Continuous polymerization process for the manufacture of superabsorbent polymers
AssigneeDow Global Technologies LLC
InventorsHerbert A. Gartner, Katrin Nuyken, Deno F. O'Connor
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Abstract
A continuous process for producing water-insoluble, water-swellable polymers comprises subjecting a monomer and initiator to polymerization conditions in a reactor system having at least 3 zones.
Claims22
A process for the preparation of water-absorbent, water-insoluble polymers, the process comprising:
- continuously polymerizing a monomer in a reactor system comprising at least 3 zones;
- wherein the first zone is an initiation zone to which there is continuously fed a monomer, an initiator and water under conditions such that the polymerization of the monomer is initiated;
- wherein the second zone is a gel-phase zone;
- wherein the third zone is a granulation zone;
- wherein the reactor system has at least two rotating shafts in each of the second and third zones;
- wherein the peak temperature in the second and third zones is from 50° C. to 100° C.;
- and
- wherein at least a portion of the water fed to the first zone optionally is in the form of steam.
5 more elements
A process for the preparation of water-absorbent, water-insoluble polymers, the process comprising:
- continuously polymerizing a monomer in a reactor system comprising at least 3 zones;
- wherein the first zone is an initiation zone to which there is continuously fed a monomer, an initiator and water under conditions such that the polymerization of the monomer is initiated;
- wherein the second zone is a highly viscous gel-phase zone;
- wherein the third zone is a granulation zone;
- wherein the reactor system has at least two rotating shafts in each of the second and third zones;
- wherein the pressure in at least the second and third zones of the reactor system is subatmospheric;
- and
- wherein at least a portion of the water fed to the first zone optionally is in the form of steam.
5 more elements
Dependencies are inferred from the claim text.