Toner coagulant processes

• US 6,576,389 B2
• Filed: 10/15/2001
• Issued: 06/10/2003
• Est. Priority Date: 10/15/2001
• Status: Expired due to Fees

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Sanders, David J., Patel, Raj D., Halfyard, Kurt I., Vanbesien, Daryl, Hopper, Michael A., Boils, Danielle C.
• Primary Examiner(s): Chapman, Mark A.
• Application Number:
  US09/976,943
• Publication Number:
  US 20030073024A1
• Time in Patent Office: 603 Days
• Field of Search: 430/137.14
• US Class Current: 430/137.14
• CPC Class Codes: G03G 9/0808 by dry mixing the toner components in solid or softened state
• CPC Class Codes: G03G 9/0819 characterised by the dimensions of the particles
• CPC Class Codes: G03G 9/0821 characterised by physical parameters magnetic parameters G03G9/083
• CPC Class Codes: G03G 9/08782 Waxes
• CPC Class Codes: G03G 9/09708 Inorganic compounds
• CPC Class Codes: G03G 9/09725 Silicon-oxides; Silicates

Abstract

A process for the preparation of toner by, for example, mixing a colorant, a latex, a wax and a dual coagulant mixture comprising water solubilized silica with an alumina coating referred to as aluminized silica and a polyaluminum chloride to provide, for example, a toner composition of different gloss levels when fused.

Claims

1. A process for the preparation of toner comprising mixing a colorant dispersion, a latex emulsion, a wax dispersion and coagulants comprising a colloidal alumina coated silica, and a polymetal halide.

2. A process in accordance with claim 1 wherein said colorant is a colorant dispersion comprised of

(i) a colorant, water, and an ionic surfactant, or a nonionic surfactant, and wherein said latex is an emulsion comprised of an ionic surfactant, water and resin;

(ii) wherein said colorant dispersion is blended with said latex emulsion, and thereafter adding a wax dispersion comprised of submicron wax particles of from about 0.1 to about 0.5 micron in diameter by volume, which wax is dispersed in an ionic surfactant of the same charge polarity of said ionic latex surfactant;

(iii) adding to the resulting blend said alumina coated silica and said metal halide of polyaluminum chloride to thereby initiate flocculation or aggregation of said resin latex, said colorant, and said wax when present;

(iv) heating the resulting mixture below about, or about equal to the glass transition temperature (Tg) of the latex resin to form toner sized aggregates;

(v) adding to the formed toner aggregates a second latex comprised of resin suspended in an aqueous phase containing an ionic surfactant and water;

(vi) adding to the resulting mixture a base to thereby change the pH which is from about 2 to about 2.9 to arrive at a pH of from about 5 to about 8 for the resulting toner aggregate mixture;

(vii) heating the resulting aggregate suspension of (vi) above about, or about equal to the Tg of the latex resin of (i);

(viii) optionally retaining the mixture temperature at from about 70°

C. to about 95°

C. optionally for a period of about 10 to about 60 minutes, followed by a pH reduction with an acid to arrive at a pH of about 3.5 to about 5 to assist in permitting the fusion or coalescence of the toner aggregates;

(ix) washing the resulting toner slurry; and

(x) isolating the toner.

3. A process in accordance with claim 2 wherein the minimum fix temperature of the toner is from of about 140°

C. to about 155°

C.

4. A process in accordance with claim 2 wherein said base is selected from the group consisting of sodium hydroxide, potassium hydroxide, and ammonium hydroxide.

5. A process in accordance with claim 2 wherein there is added to the formed toner aggregates a second latex comprised of submicron resin particles suspended in an aqueous phase containing an anionic surfactant, and wherein said second latex is selected in an amount of from about 10 to about 40 percent by weight of the initial latex to form a shell thereover on said formed aggregates, and which shell is of a thickness of about 0.2 to about 0.8 micron.

6. A process in accordance with claim 5 wherein the added latex contains the same resin as the initial latex of (i), or wherein said added latex contains a dissimilar resin than that of the initial latex.

7. A process in accordance with claim 2 wherein the pH of the mixture resulting in (vi) is increased from about 2 to about 2.6 to about 5 to about 8, and wherein said base functions primarily as a stabilizer for the aggregates during coalescence (vii), and no or minimal toner particle size or GSD increases result.

8. A process in accordance with claim 2 wherein the temperature at which toner sized aggregates are formed controls the size of the aggregates, and wherein the final toner size is from about 2 to about 15 microns in volume average diameter.

9. A process in accordance with claim 2 wherein the aggregation (iv) temperature is from about 45°

C. to about 60°

C., and wherein the coalescence or fusion temperature of (vii) is from about 85°

C. to about 95°

C.

10. A process in accordance with claim 2 wherein the latex contains a resin selected from the group consisting of poly(styrene-butadiene), poly(methylstyrene-butadiene), poly(methyl methacrylate-butadiene), poly(ethyl methacrylate-butadiene), poly(propyl methacrylate-butadiene), poly(butyl methacrylate-butadiene), poly(methyl acrylate-butadiene), poly(ethyl acrylate-butadiene), poly(propyl acrylate-butadiene), poly(butyl acrylate-butadiene), poly(styrene-isoprene), poly(methylstyrene-isoprene), poly(methyl methacrylate-isoprene), poly(ethyl methacrylate-isoprene), poly(propyl methacrylate-isoprene), poly(butyl methacrylate-isoprene), poly(methyl acrylate-isoprene), poly(ethyl acrylate-isoprene), poly(propyl acrylate-isoprene), poly(butyl acrylate-isoprene);

poly(styrene-propyl acrylate), poly(styrene-butyl acrylate), poly(styrene-butadiene-acrylic acid), poly(styrene-butadiene-methacrylic acid), poly(styrene-butadiene-acrylonitrile-acrylic acid), poly(styrene-butyl acrylate-acrylic acid), poly(styrene-butyl acrylate-methacrylic acid), poly(styrene-butyl acrylate-acrylononitrile), and poly(styrene-butyl acrylate-acrylononitrile-acrylic acid).

11. A process in accordance with claim 1 wherein said colloidal silica is a colloidal dispersion of discrete spherical particles with a purity of from about 80 to 100 percent pure amorphous silicon dioxide, and wherein the surface thereof has an alumina coating of Al₂O₃.

12. A process in accordance with claim 1 wherein the amount of colloidal alumina coated silica is from about 0.05 to about 2 percent by weight of toner and the amount of polymetal halide is about 0.14 to about 0.02 percent by weight of toner thereby optionally providing a toner exhibiting a glossy finish.

13. A process in accordance with claim 12 wherein the glossy toner exhibits a viscosity of about 35 to about 250 pascals per second at about 125°

C. to about 175°

C.

14. A process in accordance with claim 12 wherein the toner exhibits a viscosity of about 260 to about 500 pascals per second at from about 150°

C. to about 190°

C.

15. A process in accordance with claim 1 wherein the amount of colloidal alumina coated silica selected is from about 1 to about 3 percent by weight of toner and the amount of polymetal halide, which halide is polyaluminum chloride, is from about 0.3 to about 0.15 percent by weight of toner, and wherein there is provided a toner exhibiting a matte finish with a gloss of about 8 to about 35 GGU measured at a temperature of 180°

C.

16. A process in accordance with claim 1 and wherein the toner possesses a gloss of about 35 to about 80 GGU.

17. A process in accordance with claim 1 wherein the alumina (Al₂O₃) coating has a thickness of about 0.001 to about 0.01 micron, and wherein (viii), (ix) and (x) are accomplished.

18. A process in accordance with claim 1 wherein the latex resin particles are from about 0.15 to about 0.3 micron in volume average diameter.

19. A process in accordance with claim 1 wherein the colorant is a pigment, a dye or mixtures thereof, and which colorant optionally is submicron in size of about 0.08 to about 0.34 micron in average volume diameter.

20. A process in accordance with claim 1 wherein said colloidal for said alumina coated silica is of about 0.005 to about 0.1 micron in diameter.

21. A process in accordance with claim 1 wherein the colorant is a pigment, and wherein said pigment is in the form of dispersion, and which dispersion contains an ionic surfactant and optionally a nonionic surfactant, and wherein said alumina coated silica and said polymetal halide, which is polyaluminum chloride, are of a colloidal size and function as a coagulant and assists in the enablement of aggregation of said latex and said colorant.

22. A process in accordance with claim 1 wherein the latex contains a resin or polymer selected from the group consisting of poly(styrene-alkyl acrylate), poly(styrene-1,3-diene), poly(styrene-alkyl methacrylate), poly(styrene-alkyl acrylate-acrylic acid), poly(styrene-1,3-diene-acrylic acid), poly(styrene-alkyl methacrylate-acrylic acid), poly(alkyl methacrylate-alkyl acrylate), poly(alkyl methacrylate-aryl acrylate), poly(aryl methacrylate-alkyl acrylate), poly(alkyl methacrylate-acrylic acid), poly(styrene-alkyl acrylate-acrylonitrile-acrylic acid), poly(styrene-1,3-diene-acrylonitrile-acrylic acid), and poly(alkyl acrylate-acrylonitrile-acrylic acid).

23. A process in accordance with claim 1 wherein the colorant is carbon black, cyan, yellow, magenta, orange, green, violet or mixtures thereof;

the toner isolated is from about 2 to about 15 microns in volume average diameter, and the particle size distribution thereof is from about 1.15 to about 1.30; and

wherein there is added to the surface of the formed toner metal salts, metal salts of fatty acids, silicas, metal oxides, or mixtures thereof, each in an amount of from about 0.1 to about 10 weight percent of the obtained toner.

24. A process on accordance with claim 1 wherein the colloidal alumina coated silica is water solubilized in a slightly acidic pH environment, and wherein the pH is about 3 to about 6.5.

25. A process in accordance with claim 1 wherein said coagulants primarily assist in permitting aggregation and coalescence of said colorant, said latex resin and said wax, and wherein said halide is a polyaluminum chloride.

26. A process in accordance with claim 1 wherein the polymetal salt selected can be either a polyaluminum chloride or a polyaluminum sulfosilicate.

27. A process in accordance with claim 1 wherein subsequent to said mixing there is accomplished a heating at a first temperature and a subsequent heating at a second temperature, and wherein the first temperature is below the glass transition temperature of a resin contained in said latex emulsion, and wherein said second temperature is above the glass transition temperature of a resin contained in the latex emulsion.

28. A process in accordance with claim 1 wherein said colloidal aluminum coated silica is selected in an amount of from about 0.05 to about 2 weight percent.

29. A process in accordance with claim 1 wherein said polymetal halide is selected in an amount of from about 0.14 to about 0.02 percent by weight.

30. A process for the preparation of toner comprising the mixing of a colorant dispersion, a latex emulsion, a wax dispersion, a colloidal alumina coated silica, and a polymetal halide, and wherein said mixture is aggregated by heating below the latex resin glass transition temperature, and thereafter fusing said resulting aggregates by heating above the latex resin glass transition temperature wherein said aggregate mixture is at a pH of from about 5 to about 8, and wherein said latex is comprised of resin, nonionic surfactant, ionic surfactant, and water.

31. A process for the preparation of toner comprising mixing a colorant, a latex, a colloidal alumina coated silica, and a polymetal halide wherein said colloidal is of a size diameter of from about 20 to about 150 nanometers, and optionally wherein said polymetal salt is a polyaluminum chloride or a polyaluminum sulfosilicate.