Toner compositions and processes thereof

• US 5,869,215 A
• Filed: 01/13/1998
• Issued: 02/09/1999
• Est. Priority Date: 01/13/1998
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Ong, Beng S., Burns, Patricia A., Sanders, David J., Mychajlowskij, Walter, Patel, Raj D.
• Primary Examiner(s): MARTIN, ROLAND E
• Application Number:
  US09/006,508
• Time in Patent Office: 392 Days
• Field of Search: 430/137
• US Class Current: 430/137.14
• CPC Class Codes: G03G 9/0804 whereby the components are brought together in a liquid dispersing medium
• CPC Class Codes: G03G 9/08793 Crosslinked polymers
• CPC Class Codes: G03G 9/08795 characterised by their chemical properties, e.g. acidity, molecular weight, sensitivity to reactants
• CPC Class Codes: G03G 9/08797 characterised by their physical properties, e.g. viscosity, solubility, melting temperature, softening temperature, glass transition temperature

Abstract

A process for the preparation of toner including

(i) blending an aqueous colorant dispersion with a latex blend comprised of a linear polymer and a soft crosslinked polymer;

(ii) heating the resulting mixture at about below, or about equal to the glass transition temperature (Tg) of the linear latex polymer to form aggregates; and

(iii) subsequently heating said aggregate suspension about above, or about equal to the Tg of the linear latex polymer to effect fusion or coalescence of said aggregates.

Claims

1. A process for the preparation of toner comprising

(i) blending an aqueous colorant dispersion with a latex blend comprised of a linear polymer and a soft crosslinked polymer;

(ii) heating the resulting mixture at about below, or about equal to the glass transition temperature (Tg) of the linear latex polymer to form aggregates; and

(iii) subsequently heating said aggregate suspension about above, or about equal to the Tg of the linear latex polymer to effect fusion or coalescence of said aggregates, and wherein said soft crosslinked polymer is flexible and contains an acrylate in an amount of from about 25 to about 70 weight percent.

2. A process in accordance with claim 1 wherein the colorant dispersion contains an ionic surfactant, and the latex blend contains an optional nonionic surfactant, and an ionic surfactant that is of opposite charge polarity to that of the ionic surfactant in said colorant dispersion.

3. A process in accordance with claim 1 wherein the linear latex polymer is 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), or poly(alkyl acrylate-acrylonitrile-acrylic acid).

4. A process in accordance with claim 1 wherein the soft crosslinked polymer is the crosslinked analog of the linear polymer containing a monomer of propyl, butyl acrylate, pentyl acrylate, hexyl acrylate, ethylhexyl acrylate, 1,3-diene, hexyl methacrylate, or mixtures thereof.

5. A process in accordance with claim 1 wherein the crosslinked polymer is a crosslinked 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), or poly(alkyl acrylate-acrylonitrile-acrylic acid).

6. A process in accordance with claim 1 wherein the soft crosslinked polymer is derived from the polymerization of styrene, butyl acrylate, acrylic acid and divinylbenzene.

7. A process in accordance with claim 1 wherein the crosslinked polymer is derived from polymerization of monomers selected from the group consisting of styrenes, acrylates, methacrylates, 1,3-dienes, acrylonitrile, acrylic acid, and methacrylic acid in the presence of a crosslinking compound.

8. A process in accordance with claim 6 wherein butyl acrylate is present in an amount of about 25 to about 70 percent by weight of the monomers.

9. A process in accordance with claim 1 wherein the crosslinked polymer is present in an amount of from about 5 to about 75 weight percent of the toner composition, and wherein the linear polymer is present in an amount of from about 25 to about 95 weight percent of toner composition.

10. A process in accordance with claim 1 wherein the crosslinked polymer is present in an amount of from about 10 to about 50 weight percent of toner composition, and wherein the linear polymer is present in an amount of from about 50 to about 90 weight percent of toner composition.

11. A process in accordance with claim 1 wherein the toner exhibits a low fusing temperature of from about 120°

C. to about 145°

C.

12. A process in accordance with claim 1 wherein the colorant dispersion contains a cationic surfactant, and the latex blend contains a nonionic surfactant and an anionic surfactant.

13. A process in accordance with claim 1 wherein the colorant dispersion contains an anionic surfactant and the latex blend contains a nonionic surfactant and a cationic surfactant.

14. A process in accordance with claim 1 wherein the aggregation (ii) is accomplished at temperatures of from about 25°

C. to about 1°

C. below the Tg of the linear polymer for a duration of from about 0.5 hour to about 5 hours.

15. A process in accordance with claim 14 wherein the linear polymer is poly(styrene-butyl acrylate), poly(styrene-butyl acrylate-acrylic acid), poly(styrene-butadiene), poly(styrene-butadiene-acrylic acid), poly(styrene-butyl acrylate-acrylonitrile), or poly(styrene-butyl acrylate-acrylonitrile-acrylic acid), and the crosslinked resin is the crosslinked derivative of poly(styrene-butyl acrylate), poly(styrene-butyl acrylate-acrylic acid), poly(styrene-butyl acrylate-acrylonitrile), or poly(styrene-butyl acrylate-acrylonitrile-acrylic acid).

16. A process in accordance with claim 12 wherein the nonionic surfactant is selected from the group consisting of polyvinyl alcohol, methalose, methyl cellulose, ethyl cellulose, propyl cellulose, hydroxy ethyl cellulose, carboxy methyl cellulose, polyoxyethylene cetyl ether, polyoxyethylene lauryl ether, polyoxyethylene octyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene sorbitan monolaurate, polyoxyethylene stearyl ether, polyoxyethylene nonylphenyl ether, and dialkylphenoxy poly(ethyleneoxy)ethanol;

and wherein the anionic surfactant is selected from the group consisting of sodium dodecyl sulfate, sodium dodecylbenzene sulfate, sodium dodecylnaphthalene sulfate, and the cationic surfactant is a quaternary ammonium salt.

17. A process in accordance with claim 1 wherein the colorant is carbon black, magnetite, cyan, yellow, magenta, and mixtures thereof.

18. A process in accordance with claim 2 wherein the surfactants are each present in an effective amount of from about 0.1 to about 5 weight percent of the reaction mixture.

19. A process in accordance with claim 1 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 particles.

20. A process in accordance with claim 1 wherein after cooling the toner is isolated, washed with water or an aqueous base solution at a temperature of from about 25°

C. to about 75°

C. to remove the residual surfactants from the toner, and wherein the fusion or coalescence is accomplished at a temperature of from about 65°

C. to about 100°

C.

21. A process in accordance with claim 1 wherein subsequent to (iii) cooling is accomplished, and the toner is isolated, washed, and dried.

24. A process in accordance with claim 1 wherein said soft crosslinked polymer contains acrylate in an amount of about 25 to about 55 percent by weight of the latex monomers.

25. A process in accordance with claim 1 wherein said acrylate is present in an amount of from about 25 to about 55 weight percent.

26. A process in accordance with claim 1 wherein said soft crosslinked polymer is comprised of styrene, butyl acrylate and acrylic acid.

27. A process in accordance with claim 26 wherein said polymer is crosslinked with divinyl benzene.

22. A process for the preparation of toner comprising heating a mixture of an aqueous colorant dispersion containing a first ionic surfactant, and a latex blend comprised of linear polymer and soft crosslinked polymer particles, a nonionic surfactant and a second ionic surfactant with a charge polarity opposite to that of said ionic surfactant in said colorant dispersion;

heating the resulting mixture at about below the glass transition temperature (Tg) of the linear latex polymer to form toner sized aggregates; and

subsequently heating said aggregates about above the Tg of the linear latex polymer to effect coalescence of said aggregates, followed by optionally isolating said toner, and optionally washing said toner, and wherein said soft crosslinked polymer particles contain from about 25 to about 70 weight percent of an acrylate.

23. A process in accordance with claim 22 wherein the crosslinked polymer particles are present in amounts of from about 5 percent to about 75 percent by weight of the toner, and wherein the linear polymer particles are present in an amount of from about 25 to about 95 by weight of the toner.