Crash cooling method to prepare toner
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, hot toner slurry is added to an external reactor containing a coolant comprised of previously cooled toner slurry in combination with cooled de-ionized water. The previously cooled toner slurry found in the coolant has the same toner composition as the incoming hot toner slurry. Also, the amount of the coolant in the external reactor is equivalent to the amount of incoming hot toner slurry. Polyester toners and polyester core shell toners having a borax coupling agent between the toner core and toner shell made from this crash cooling process results in an improvement to the toner performance especially a decrease in the overall toner usage.
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 having the borax coupling agent to form toner shells around the toner cores;
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 into an external reactor containing a coolant having a temperature between 8° C. and 25° C., wherein the coolant contains a mixture of de-ionized water and a cooled toner slurry having the same composition as the hot toner slurry being added into the external reactor;
filtering the toner particles out of the hot toner slurry;
washing the filtered toner particles; and
repeating the filtering and washing steps until toner particles have an average particle size of between about 3 μm and about 10 μm.
2. The method of claim 1 , wherein the ratio of the de-ionized water to the cooled toner slurry in the coolant is between 98:2 by weight and 60:40 by weight.
3. The method of claim 2 , wherein the ratio of the de-ionized water to the cooled toner slurry in the coolant is about 70:30 by weight.
4. The method of claim 1 , wherein the ratio of the hot toner slurry being added into the external reactor to the coolant in the external reactor is 1:1 by weight.
5. The method of claim 1 , wherein the hot toner slurry has a temperature between 80° C. and 84° C.
6. The method of claim 1 , wherein the first polymer emulsion and the second polymer emulsion each include an amorphous resin.
7. A toner prepared by the process of claim 1 .