Co-emulsification of insoluble compounds with toner resins

Abstract

A process for making a latex emulsion suitable for use in a toner composition includes co-emulsifying a bio-based resin with an insoluble component, such as a pigment or wax, whereby the resin encapsulates the insoluble component. The resulting latex, including the insoluble component encapsulated in the resin, may then be utilized to form a toner. The insoluble component may thus be included in toner particles, which might otherwise be difficult to achieve, using emulsion aggregation processes.

Claims

1. A toner comprising at least one polyester resin encapsulating a colorant, wherein said colorant is insoluble in a solution comprising an organic solvent and said at least one polyester resin.

2. The toner of claim 1, wherein the at least one polyester resin comprises a bio-based resin including monomers selected from the group consisting of a fatty dimer acid, a fatty dimer diol, D-isosorbide, naphthalene dicarboxylate, azelaic acid, succinic acid, cyclohexanedioic acid, naphthalene dicarboxylic acid, terephthalic acid, glutamic acid, and combinations thereof.

3. The toner of claim 2, wherein the bio-based resin further comprises an alcohol selected from the group consisting of ethylene glycol, propylene glycol, 1,3-propanediol, and combinations thereof.

4. The toner of claim 1, where said colorant is selected from the group consisting of carbon black, titanium dioxide, Pigment Yellow 180, Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 17, Pigment Blue 15, Pigment Blue 15:3, Pigment Red 81:1, Pigment Red 81:2, Pigment Red 81:3, Pigment Yellow 74, Pigment Yellow 14, Pigment Yellow 83, Pigment Orange 34, Pigment Red 238, Pigment Red 122, Pigment Red 48:1, Pigment Red 269, Pigment Red 53:1, Pigment Red 57:1, Pigment Red 83:1, Pigment Violet 23, Pigment Green 7, and combinations thereof.

5. The toner of claim 1, further comprising a wax.

6. The toner of claim 5, wherein said wax is encapsulated.

7. The toner of claim 6, wherein said encapsulated wax has a particle size from about 10 nm to about 500 nm.

8. The toner of claim 5, wherein the wax is selected from the group consisting of polyolefins, functionalized polyolefin waxes, polyethylene/amide, polyethylenetetrafluoroethylene, polyethylenetetrafluoroethylene/amide, polybutene waxes, and combinations thereof.

9. The toner of claim 1, wherein said colorant is present in an amount of from about 0.1% to about 35% by weight of the toner.

10. The toner of claim 5, wherein the wax is present in an amount of from about 1% to about 25% by weight of the toner.

11. The toner of claim 1, further comprising an external additive.

12. The toner of claim 1, wherein the encapsulated colorant has a particle size from about 10 nm to about 500 nm.

13. The toner of claim 1, further comprising an encapsulated wax, wherein said encapsulated wax comprises a wax and at least one polyester resin encapsulating said wax.

14. The toner of claim 1, further comprising an amorphous resin.

15. The toner of claim 1, further comprising a crystalline resin.

16. The toner of claim 1, comprising core-shell particles.

17. The toner of claim 16, wherein said shell comprises an encapsulated colorant.

18. A developer comprising the toner of claim 1.

19. The developer of claim 18 comprising a carrier.

20. The developer of claim 19, wherein said carrier comprises a coating.

Description

EXAMPLES

Comparative Example 1

(1) Preparation of an emulsion aggregation (EA) toner, where a pigment dispersion was added separately in the toner formulation. Into a 1000 ml glass beaker equipped with a magnetic stir bar and a hotplate, about 296.74 grams of an emulsion containing 100% by weight of a bio-based resin made from 50% isosorbide, 45% succinic acid, and 5% azelaic acid, about 20.45 grams of a cyan pigment dispersion (Pigment Blue 15:3 (17% by weight), and about 2.91 grams of DOWFAX 2A1, an alkyldiphenyloxide disulfonate (commercially available from the Dow Chemical Company) (about 47% by weight). The above mixture was cooled to about 8 C. using an ice bath. After the pH was adjusted to about 4.2, about 22.29 grams of Al.sub.2(SO.sub.4).sub.3 solution (about 1% by weight) was added as a flocculent under homogenization. The temperature of the mixture was increased to about 17.9 C. with stirring at about 900 revolutions per minute (rpm). The particle size was monitored with a Coulter Counter until the core particles reached a volume average particle size of about 5.83 m, with a volume average Geometric Size Distribution (GSDv) of about 1.27.

(2) A sample taken at this point visibly showed severe pigment rejection.

(3) The pH of the reaction slurry was then increased to about 7.5 using about 1.72 grams of ethylene diamine tetraacetic acid (EDTA) about (39% by weight) and NaOH (about 4% by weight) to freeze, i.e., stop, the toner growth. After freezing, the reaction mixture was heated to about 40.7 C., and the pH was reduced to about 7.01 for coalescence. The toner was quenched after coalescence, and it had a final particle size of about 5.48 microns, a GSDv of about 1.33, and a circularity of about 0.965.

(4) A sample of the above toner slurry was taken and settled in a glass vial. The sample had severe pigment rejection, and toner having a very light color settled at the bottom of the vial.

Example 1

(5) Preparation of latex with pigment encapsulated in bio-resin particles. About 56.7 grams of the 100% bio based resin described above in Comparative Example 1 was measured into a 2 liter beaker containing about 500 grams of dichloromethane. The mixture was stirred at about 300 revolutions per minute at room temperature to dissolve the resin in the dichloromethane, thereby forming a resin solution.

(6) About 21.16 grams of the cyan pigment dispersion described above in Comparative Example 1 (about 17% by weight containing 9 parts per hundred (pph) of a branched sodium dodecyl benzene sulfonate surfactant from Tayca Corporation (Japan)) together with about 1.14 grams of sodium bicarbonate and about 2.41 grams DOWFAX 2A1, an alkyldiphenyloxide disulfonate (commercially available from the Dow Chemical Company) (about 47% by weight) was measured into a 3 liter Pyrex glass flask reactor containing about 300 grams of deionized water, thereby forming a water solution. Homogenization of said water solution in said 3 liter glass flask reactor was commenced with an IKA Ultra Turrax T50 homogenizer operating at about 4,000 revolutions per minute. The resin solution was then slowly poured into the water solution. As the mixture continued to be homogenized, the homogenizer speed was increased to about 8,000 revolutions per minute and homogenization was carried out at these conditions for about 30 minutes. Upon completion of homogenization, the glass flask reactor and its contents were placed in a heating mantle and connected to a distillation device.

(7) The mixture was stirred at about 200 revolutions per minute and the temperature of the mixture was increased to about 50 C. at a rate of about 1 C. per minute to distill off the dichloromethane from the mixture. Stirring continued at about 50 C. for about 180 minutes, followed by cooling at about 2 C. per minute to room temperature. The product was screened through a 25 micron sieve.

(8) The resulting resin emulsion included about 19.39 percent by weight solids in water, with an average particle size of 141.2 nm.

Example 2

(9) Preparation of EA toner with pigment encapsulated in a bio-resin emulsion. Into a 1000 ml glass beaker equipped with a magnetic stir bar and a hotplate, about 3.07 grams DOWFAX 2A1, an alkyldiphenyloxide disulfonate (commercially available from the Dow Chemical Company) (about 47% by weight), was combined with about 304.05 grams of the latex from Example 1, including the bio-based resin with encapsulated cyan pigment. The mixture was cooled to about 8 C. using an ice bath. After the pH of the components was adjusted to about 4.2, about 23.02 grams of Al.sub.2(SO.sub.4).sub.3 solution (1% by weight) was added as a flocculent under homogenization. The temperature of the mixture was increased to about 19 C. with mixing at about 900 rpm. The particle size was monitored with a Coulter Counter until the core particles reached a volume average particle size of about 6.15 m with a GSDv of about 1.26.

(10) A sample taken at this point had clear mother liquor. The pH of the reaction slurry was then increased to about 7.3 using about 1.79 grams EDTA (about 39% by weight) and NaOH (about 4% by weight) to freeze, i.e., stop, the toner growth.

(11) After freezing, the reaction mixture was heated to about 40.3 C., and the pH was about 7. The toner was quenched after coalescence, and it had a final particle size of about 5.48 microns, a volume average Geometric Size Distribution of about 1.26, and a circularity of about 0.969.

(12) A sample of the above toner slurry was taken and settled in a glass vial. The sample had reasonably clear mother liquor, and toner having the expected cyan color settled at the bottom.

(13) Following the above synthesis, it was found that an organic based pigment stayed in the latex particles. The pigment was thus incorporated in toner particles successfully by aggregating the pigment containing latex.

Example 3

(14) Preparation of a latex with wax encapsulated in bio-resin particles. About 69 grams of the bio based resin described above in Comparative Example 1 was measured into a 2 liter beaker containing about 700 grams of dichloromethane. The mixture was stirred at about 300 revolutions per minute at room temperature to dissolve the resin in the dichloromethane, thereby forming a resin solution.

(15) About 36.45 grams of a polyethylene wax, commercially available as IGI wax in a dispersion (about 30.37% by weight) and about 41.8 grams of the cyan pigment dispersion described above in Comparative Example 1 (about 17% by weight containing 9 parts per hundred (pph) of the branched sodium dodecyl benzene sulfonate surfactant from Tayca Corporation) together with about 1.1 grams of sodium bicarbonate and about 2.94 grams DOWFAX 2A1, an alkyldiphenyloxide disulfonate (commercially available from the Dow Chemical Company) (about 47% by weight) was measured into a 3 liter Pyrex glass flask reactor containing about 500 grams of deionized water, thereby forming a water solution. Homogenization of the water solution in the 3 liter glass flask reactor was commenced with an IKA Ultra Turrax T50 homogenizer operating at about 4,000 revolutions per minute. The resin solution was then slowly poured into the water solution. As the mixture continued to be homogenized, the homogenizer speed was increased to about 8,000 revolutions per minute and homogenization was carried out at these conditions for about 30 minutes.

(16) Upon completion of homogenization, the glass flask reactor and its contents were placed in a heating mantle and connected to a distillation device. The mixture was stirred at about 200 revolutions per minute and the temperature of the mixture was increased to about 50 C. at a rate of about 1 C. per minute to distill off the dichloromethane from the mixture. Stirring of the mixture continued at about 50 C. for about 150 minutes followed by cooling at about 2 C. per minute to room temperature. The product was screened through a 25 micron sieve. The resulting resin emulsion included about 14.26 percent by weight solids in water.

Example 4

(17) Preparation of EA toner with the wax encapsulated resin. About 3.59 grams DOWFAX 2A1, an alkyldiphenyloxide disulfonate (commercially available from the Dow Chemical Company) (about 47% by weight) and about 391.13 grams of the latex from Example 3 were added to a 2 liter glass reactor equipped with an overhead stirrer. The mixture was cooled to about 8 C. using an ice bath, and the pH was adjusted to about 4.2. About 46.79 grams of Al.sub.2(SO.sub.4).sub.3 solution (about 1% by weight) was added as a flocculent under homogenization. The temperature of the mixture was increased to about 17.1 C. with stirring at about 300 rpm. The particle size was monitored with a Coulter Counter until the core particles reached a volume average particle size of about 4.78 m, with a GSDv of about 1.19. About 150.48 grams of the same bio-based resin used in Example 3 in an emulsion (about 17.84% by weight, with no wax or pigment) was added as shell, resulting in core-shell structured particles having an average particle size of about 6.21 microns, and a GSDv of about 1.23.

(18) Thereafter, the pH of the reaction slurry was increased to about 8 using about 3.62 grams EDTA (about 39% by weight) and NaOH (about 4% by weight) to freeze, i.e., stop, the toner growth. After freezing, the reaction mixture was heated to about 40.3 C., and pH was about 7. The toner was quenched after coalescence, and it had a final particle size of about 9.44 microns, and a volume average GSD of about 1.35.

(19) Differential Scanning calorimetry (DSC) of the toner sample showed that about 11% of the wax was incorporated into the toner, compared with 9% of wax that was initially put in the toner formulation. Thus, after aggregating the wax containing latex, DSC proved that the IGI polyethylene wax was successfully incorporated into the toner.

(20) It will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims. Unless specifically recited in a claim, steps or components of claims should not be implied or imported from the specification or any other claims as to any particular order, number, position, size, shape, angle, color, or material.