Crash cooling method to prepare toner
View Patent ↗The present disclosure relates generally to a method to make a chemically prepared toner that employs a crash cooling process. In the crash cooling process, an amount of hot toner slurry is added to an external reactor holding an amount of chilled cooling water, wherein the temperature of the chilled cooling water in the external reactor is from about 8° C. to about 25° C. The amount of the chilled cooling water in the external reactor is about 10% to about 40% lower compared to the amount of the added hot toner slurry. Toner prepared using this crash cooling method is cooled at a rate of less than 0.8° C./min. Polyester toners and polyester core shell toners having a borax coupling agent between the toner core and toner shell made from this crash cooling processes using less water results in an improvement to the toner's print density and usage efficiency.
1. A method for producing a core shell toner, comprising:
combining and agglomerating a polymer emulsion with a colorant dispersion and a release agent dispersion to form toner cores;
adding a borax coupling agent to the toner cores once the toner cores reach a predetermined size;
combining and agglomerating a second polymer emulsion with the toner cores to form toner shells around the toner cores, wherein the first polymer emulsion and the second polymer emulsion each include an amorphous polyester resin;
fusing the aggregated toner cores and toner shells to form toner particles;
forming a hot toner slurry by suspending the toner particles in an aqueous medium wherein the hot toner slurry has a temperature between 70° C. and 90° C.;
adding the hot toner slurry to cold water in an external container wherein the cold water has a temperature between 5° C. and 20° C. and the quantity of the hot toner slurry is equivalent to the quantity of the cold water;
filtering the toner particles out of the hot toner slurry;
washing the filtered toner particles with deionized water; and
repeating the filtering and washing steps until the conductivity of the filtered toner particles less than or equal to 5 μS/cm.
2. The method of claim 1 , wherein the ratio of the hot toner slurry to the chilled cooling water is about 1:0.75 by weight.
3. The method of claim 1 , wherein the hot toner slurry has a temperature between 80° C. and 84° C.
4. The method of claim 1 , wherein the chilled cooling water has a temperature about 20° C.
5. A toner prepared by the process of claim 1 .