Processes for producing polyester latexes via solvent-based and solvent-free emulsification
View Patent ↗A process for making a latex emulsion suitable for use in a toner composition includes contacting at least one polyester resin optionally with an organic solvent to form a resin mixture, adding a primary amine, optionally a surfactant, and deionized water to the mixture.
1. A process comprising:
contacting at least one polyester resin with least one organic solvent and a phase inversion agent to form a resin mixture;
neutralizing said at least one polyester resin with a tris(hydroxymethyl) aminomethane (Tris);
adding water to the mixture to provide a latex emulsion containing latex particles; and
continuously recovering the latex particles.
2. The process according to claim 1 , wherein the at least one polyester resin is selected from the group consisting of amorphous resins, crystalline resins, and combinations thereof.
3. The process according to claim 1 , wherein the at least one organic solvent and the phase inversion agent is selected from the group consisting of alcohols, esters, ethers, ketones, amines, and combinations thereof, in an amount of from about 0.1% by weight to about 99% by weight of the polyester resin.
4. The process according to claim 1 , wherein adding the water occurs at temperatures of from about 25° C. to about 140° C.
5. The process according to claim 1 , wherein the polyester resin is a resin having a number average molecular weight of from about 1,000 to about 50,000, a weight average molecular weight of from about 2,000 to about 150,000, and a molecular weight distribution of from about 1.5 to about 50.
6. The process according to claim 1 , wherein the Tris is present in an amount from about 0.001% to 50% by weight of the resin and is added at a rate of from about 0.4 grams/minute to about 400 kilograms/minute.
7. The process according to claim 1 , wherein the latex particles have a particle size of about 30 nanometers to about 500 nanometers.
8. A process for preparing a polyester emulsion comprising:
contacting at least one polyester resin with a tris(hydroxymethyl) aminomethane (Tris) in the absence of an organic solvent to form a mixture;
melt mixing the mixture;
adding a concentrated surfactant to the mixture;
adding water to the mixture to provide a latex emulsion containing latex particles;
optionally adding one or more additional ingredients of a toner composition to the mixture; and
continuously recovering the latex particles.
9. The process according to claim 8 , wherein the Tris is present in an amount from about 0.001% to 50% by weight of the resin and is added at a rate of from about 0.4 grams/minute to about 400 kilograms/minute.
10. The process according to claim 8 , wherein melt mixing occurs at a temperature of from about 25° C. to about 300° C. and at a rate of from about 10 rpm to about 5,000 rpm, and wherein adding the water occurs at a temperature of from about 25° C. to about 140° C.
11. The process according to claim 8 , wherein the polyester resin is a resin having a number average molecular weight of from about 1,000 to about 50,000, a weight average molecular weight of from about 2,000 to about 150,000, and a molecular weight distribution of from about 1.5 to about 50.
12. The process according to claim 8 , wherein the surfactant is selected from the group consisting of anionic surfactants, ionic surfactants, nonionic surfactants, cationic surfactants, and combinations thereof, and the surfactant is present in an amount from about 0.01% to about 20% by weight of the resin.
13. The process according to claim 8 , wherein the water is added to the resin mixture at a rate of about 10 grams/minute to about 10 kilograms/minute.
14. A toner comprising:
at least one polyester resin neutralized with a tris(hydroxymethyl) aminomethane; and
optionally one or more additional ingredients of a toner composition.
15. The toner according to claim 14 , wherein the at least one polyester resin is selected from the group consisting of amorphous resins, crystalline resins, and combinations thereof.
16. The toner according to claim 14 , wherein the toner has a particle size of from about 2 microns to about 10 microns.
17. The toner according to claim 14 , wherein the toner has a volume average particle size distribution index of from about 1 to about 1.8, and a circularity of from about 0.6 to about 1.
18. The toner according to claim 14 , wherein the polyester resin is a resin having a number average molecular weight of from about 1,000 to about 50,000, a weight average molecular weight of from about 2,000 to about 150,000, and a molecular weight distribution Mw/Mn of from about 1.5 to about 50.