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US 9,874,825 B2Granted
Continuous coalescence processes
AssigneeXerox Corporation
InventorsJoo T. Chung, Chieh-Min Cheng, Steven M. Malachowski, Eric Joseph Young, Eric David Godshall, Brian Joseph Marion
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Abstract
Processes for continuously coalescing particles from an aggregated particle slurry are disclosed. The aggregated particle slurry is heated, then coalesced by raising the pH. The coalesced particles are homogenized and exit as a coalesced particle slurry. A multi-screw extruder is used for the coalescing. These processes are useful for providing coalesced particles such as toner compositions.
Claims20
Coalesced particles useful for producing toner compositions, wherein the coalesced particles are produced by a continuous process comprising:
- (a) feeding an aggregated particle slurry into a multi-zone extruder for a predetermined residence time;
- (b) heating the aggregated particle slurry to a temperature of from about 70° C. to about 98° C. in a first zone of the multi-zone extruder;
- (c) adding a caustic solution to raise the pH of the aggregated particle slurry and form a coalesced particle slurry in a second zone of the multi-zone extruder downstream of the first zone;
- (d) homogenizing the particles in the coalesced particle slurry in a third zone of the multi-zone extruder downstream of the second zone;
- (e) measuring circularity of the particles in the coalesced particle slurry and changing the residence time within the multi-zone extruder until the circularity of the particles in the coalesced particle slurry are of a predetermined value;
- and
- (f) removing the coalesced particle slurry of the predetermined particle circularity from an outlet port of the multi-zone extruder, wherein the particle circularity enables the coalesced particles to be useful for producing toner compositions.
4 more elements
Dependencies are inferred from the claim text.