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US 9,639,013 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.
Claims9
A continuous process for coalescing particles, comprising:
- feeding an aggregated particle slurry into a multi-screw extruder for a predetermined residence time;
- heating the aggregated particle slurry to a temperature of about 70° C. to about 98° C. in a first zone of the extruder;
- 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 extruder downstream of the first zone;
- homogenizing the particles in the coalesced particle slurry in a third zone of the extruder downstream of the second zone;
- measuring circularity of the particles in the coalesced particle slurry and changing the residence time within the extruder until the circularity of the particles in the coalesced particle slurry are of a predetermined value;
- and
- pumping the coalesced particle slurry of the predetermined particle circularity from an outlet port of the multi-screw extruder.
4 more elements
Dependencies are inferred from the claim text.