Styrene-acrylate toner composition

Abstract

To provide a toner that meets requirements of an intended machine including hot offset, gloss, aging, and storage stability characteristics.SOLUTION: A toner comprises: toner particles each including a core and a shell thereover, where the core comprises at least one styrene-acrylate copolymer selected from styrene-acrylate copolymer 1, styrene-acrylate copolymer 2, and styrene-acrylate copolymer 3, and combinations thereof; a wax; and an optional colorant. The shell comprises at least one styrene-acrylate copolymer selected from styrene-acrylate copolymer 1, styrene acrylate copolymer 2, styrene acrylate copolymer 3, and combinations thereof.SELECTED DRAWING: None

Description

[Background technology]

[0001] 1. A toner comprising: toner particles including a core and a shell thereon, the core comprising at least one styrene-acrylate copolymer selected from a first core styrene-acrylate copolymer, a second core styrene-acrylate copolymer, and a third core styrene-acrylate copolymer, or combinations thereof; a wax; and an optional colorant, wherein the first core styrene-acrylate copolymer has an average molecular weight of about 32,000 toner particles; the second core styrene-acrylate copolymer has a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0° C. to about 57.0° C.; the third core styrene-acrylate copolymer has a weight average molecular weight of about 33,000 g / mol to about 39,000 g / mol and an onset glass transition temperature of about 49.0° C. to about 61.0° C. and an onset glass transition temperature of from about 53.0°C to about 53.0°C, the shell comprising at least one styrene-acrylate copolymer selected from a first shell styrene-acrylate copolymer, a second shell styrene-acrylate copolymer, a third shell styrene-acrylate copolymer, or a combination thereof, the first shell styrene-acrylate copolymer having a weight average molecular weight of from about 32,000 g / mol to about 38,000 g / mol and a viscosity modulus of about 57. A toner is disclosed, wherein the first shell styrene-acrylate copolymer has an onset glass transition temperature of 0°C to about 61.0°C, the second shell styrene-acrylate copolymer has a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol, and an onset glass transition temperature of about 53.0°C to about 57.0°C, and the third shell styrene-acrylate copolymer has a weight average molecular weight of about 33,000 g / mol to about 39,000 g / mol, and an onset glass transition temperature of about 49.0°C to about 53.0°C.

[0002] 1. A method of preparing a toner comprising emulsion aggregation core-shell toner particles, comprising toner particles comprising a core and a shell thereon, the core comprising at least one styrene-acrylate copolymer selected from a first styrene-acrylate copolymer, a second styrene-acrylate copolymer, and a third styrene-acrylate copolymer, or combinations thereof, a wax, and an optional colorant, wherein the first styrene-acrylate copolymer has an average molecular weight of from about 32,000 g / mol to about 32,000 g / mol. the second styrene-acrylate copolymer has a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0° C. to about 57.0° C.; the third styrene-acrylate copolymer has a weight average molecular weight of about 33,000 g / mol to about 39,000 g / mol and an onset glass transition temperature of about 49.0° C. to about 53.0° C.; and the shell is the first styrene-acrylate copolymer. and optionally a solution of a chelating agent; stopping further aggregation and increasing the temperature to a second temperature higher than the first temperature to coalesce the aggregated particles; and subsequently cooling and optionally washing and recovering the emulsion aggregation toner particles.

[0003] Styrene-acrylate toner compositions are desirable for toners and toner / developers that desirably meet several requirements for the intended machine, including high temperature offset, gloss, aging, and shelf stability properties.

[0004] U.S. Patent No. 7,455,943, incorporated herein by reference in its entirety, describes a toner comprising emulsion aggregation toner particles of a binder comprising a non-crosslinked styrene acrylate polymer, at least one colorant, at least one wax, and aluminized silica, wherein the amount of aluminum metal in the toner particles is from about 50 ppm to about 600 ppm. Such a toner can provide a high level of gloss while maintaining a low minimum fixing temperature. The aluminized silica acts as a coagulant during the emulsion aggregation formation process of the toner.

[0005] U.S. Patent No. 10,409,185, the entirety of which is incorporated herein by reference, describes a method of forming a toner. In an embodiment, such a method comprises forming a toner from a mixture of at least one resin, at least one wax, and optionally at least one colorant, the at least one wax being of one type and selected to provide a predetermined PER of the toner. 10 and forming a toner having a PER present in an amount selected to provide a 10 measuring a measured PER value of the toner; 10 The value is the given PER 10 and measuring the toner content is less than or equal to a value. A toner formed using this method is also provided.

[0006] U.S. Patent Application No. 16 / 800,176, filed February 25, 2020, and entitled "Dual Wax Toner Composition," which is incorporated by reference in its entirety, describes a toner composition comprising a first wax and a second wax different from the first wax, where the first wax comprises a paraffin wax and the second wax comprises a polymethylene wax, and further comprising at least one polyester and an optional colorant.

[0007] Currently available toner compositions are suitable for their intended purposes. However, there remains a need for improved toner compositions. Furthermore, there remains a need for improved styrene-acrylate toner compositions. Still further, in embodiments, for single component development machines using black toners, there remains a need for improved styrene-acrylate toner compositions suitable for single component development machines. Still further, there remains a need for improved styrene-acrylate toner compositions that meet the requirements of the intended machine, including hot offset, gloss, aging, and storage stability properties.

[0008] The appropriate components and process aspects of each of the above U.S. patents and published patent applications may be selected for the present disclosure in its embodiments. Additionally, throughout this application, various publications, patents, and published patent applications are referenced by specific citations. The disclosures of the publications, patents, and published patent applications referenced in this application are hereby incorporated by reference into this disclosure in order to more fully describe the state of the art to which this invention pertains. Summary of the Invention

[0009] 1. A toner comprising: toner particles including a core and a shell thereon, the core comprising at least one styrene-acrylate copolymer selected from a first core styrene-acrylate copolymer, a second core styrene-acrylate copolymer, and a third core styrene-acrylate copolymer, or combinations thereof; a wax; and an optional colorant, wherein the first core styrene-acrylate copolymer has an average molecular weight of about 32,000 toner particles; the second core styrene-acrylate copolymer has a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0° C. to about 57.0° C.; the third core styrene-acrylate copolymer has a weight average molecular weight of about 33,000 g / mol to about 39,000 g / mol and an onset glass transition temperature of about 49.0° C. to about 61.0° C. and an onset glass transition temperature of from about 53.0°C to about 53.0°C, the shell comprising at least one styrene-acrylate copolymer selected from a first shell styrene-acrylate copolymer, a second shell styrene-acrylate copolymer, a third shell styrene-acrylate copolymer, or a combination thereof, the first shell styrene-acrylate copolymer having a weight average molecular weight of from about 32,000 g / mol to about 38,000 g / mol and a viscosity modulus of about 57. The toner described herein is one having an onset glass transition temperature of 0°C to about 61.0°C, a second shell styrene-acrylate copolymer having a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol, and an onset glass transition temperature of about 53.0°C to about 57.0°C, and a third shell styrene-acrylate copolymer having a weight average molecular weight of about 33,000 g / mol to about 39,000 g / mol, and an onset glass transition temperature of about 49.0°C to about 53.0°C.

[0010] 1. A method of preparing a toner comprising emulsion aggregation core-shell toner particles, comprising toner particles comprising a core and a shell thereon, the core comprising at least one styrene-acrylate copolymer selected from a first styrene-acrylate copolymer, a second styrene-acrylate copolymer, and a third styrene-acrylate copolymer, or combinations thereof, a wax, and an optional colorant, wherein the first styrene-acrylate copolymer has an average molecular weight of about 32,000 g / mol to about 32,000 g / mol. the second styrene-acrylate copolymer has a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0° C. to about 57.0° C.; the third styrene-acrylate copolymer has a weight average molecular weight of about 33,000 g / mol to about 39,000 g / mol and an onset glass transition temperature of about 49.0° C. to about 53.0° C.; and the shell is the first styrene-acrylate copolymer. and optionally a solution of a chelating agent is added to the emulsion aggregation toner particles. Also described is a method for preparing an emulsion aggregation toner comprising: obtaining a core styrene-acrylate copolymer latex, an optional aqueous dispersion of a colorant, and an aqueous dispersion of a wax; forming a mixture of the core styrene-acrylate copolymer latex, the optional aqueous dispersion of a colorant, and the aqueous dispersion of a wax; heating the mixture to a first temperature; maintaining the first temperature to form aggregate toner particles; adding a shell styrene-acrylate copolymer latex to form a shell on the aggregated particles; optionally adding a solution of a chelating agent; stopping further aggregation and increasing the temperature to a second temperature higher than the first temperature to coalesce the aggregated particles; and subsequently cooling and optionally washing and recovering the emulsion aggregation toner particles. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Toner particles are described that are comprised of a core resin comprising a styrene-acrylate copolymer, a shell resin comprising a styrene-acrylate copolymer, an optional pigment, a wax release agent, and in embodiments, are prepared with a flocculating agent and a chelating agent.

[0012] In an embodiment, a toner is described, the toner being toner particles comprising a core and a shell thereon, the core comprising at least one styrene-acrylate copolymer, in embodiments a combination of at least two styrene-acrylate copolymers selected from a first styrene-acrylate copolymer (Styrene-Acrylate Copolymer 1), a second styrene-acrylate copolymer (Styrene-Acrylate Copolymer 2), and a third styrene-acrylate copolymer (Styrene-Acrylate Copolymer 3). , toner particles, a wax, and an optional colorant, wherein the first core styrene-acrylate copolymer has a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0° C. to about 61.0° C., the second core styrene-acrylate copolymer has a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0° C. to about 57.0° C., and the third core styrene-acrylate copolymer has a weight average molecular weight of about 33,000 g / mol to about 39,000 g / mol and an onset glass transition temperature of about 54.0° C. to about 55.0° C. and an onset glass transition temperature of about 49.0° C. to about 53.0° C., the shell comprising at least one styrene-acrylate copolymer selected from a first shell styrene-acrylate copolymer, a second shell styrene-acrylate copolymer, a third styrene-acrylate copolymer, or a combination thereof, the first shell styrene-acrylate copolymer (styrene-acrylate copolymer 1) having a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol, and and an onset glass transition temperature of about 57.0°C to about 61.0°C; the first shell styrene-acrylate copolymer (styrene-acrylate copolymer 2) has a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol, and an onset glass transition temperature of about 53.0°C to about 57.0°C; and the third shell styrene-acrylate copolymer (styrene-acrylate copolymer 3) has a weight average molecular weight of about 33,000 g / mol to about 39,000 g / mol, and an onset glass transition temperature of about 49.0°C to about 53.0°C.

[0013] Molecular weight is determined by gel permeation chromatography according to conventional methods. Onset Tg (onset glass transition temperature) is measured using differential scanning calorimetry and is defined as the intersection of the lines tangent to both the heat flow curves before and after the glass transition.

[0014] In an embodiment, a toner is described, the toner comprising emulsion aggregation toner particles comprising a core and a shell thereon, the core comprising a combination of at least two styrene-acrylate copolymers selected from a first core styrene-acrylate copolymer, a second styrene-acrylate copolymer, and a third styrene-acrylate copolymer, a wax, and an optional colorant, the first core styrene-acrylate copolymer having a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0° C. to about 61.0° C., the second core styrene-acrylate copolymer having a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0° C. to about 57.0° C., and a wax and an optional colorant. and the third core styrene-acrylate copolymer has a weight average molecular weight of about 33,000 g / mol to about 39,000 g / mol and an onset glass transition temperature of about 49.0° C. to about 53.0° C., and the shell comprises at least one styrene-acrylate copolymer selected from a first shell styrene-acrylate copolymer, a second shell styrene-acrylate copolymer, a third, or a combination thereof, and the first shell styrene-acrylate copolymer has a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0° C. to about 61.0° C., and the second shell styrene-acrylate copolymer has a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0° C. to about 57.and has an onset glass transition temperature of 0° C., the toner comprises from about 50 to about 80 weight percent core, the toner comprises from about 50 to about 60 weight percent core, or from about 52 to about 56 weight percent core, from about 20 to about 36 weight percent shell, or from about 24 to about 32 weight percent shell, or from about 26 to about 30 weight percent shell, from about 3 to about 10 weight percent colorant, or from about 4 to about 8 percent, or from about 5 to about 7 percent colorant, from about 5 to about 20 weight percent wax, or from about 7 to about 20 weight percent wax, or from about 9 to about 16 percent wax, where the percentages are weight percent based on the total weight of the toner.

[0015] In a specific embodiment, the toner core comprises a combination of a first styrene-acrylate copolymer having a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0° C. to about 61.0° C. and a second core styrene-acrylate copolymer having a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0° C. to about 57.0° C.; and the toner shell comprises a single shell resin, the shell resin being the first core styrene-acrylate copolymer having a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0° C. to about 61.0° C.

[0016] In certain embodiments, a toner is described, the toner comprising a pigment, in embodiments carbon black, present in an amount of from about 3 to about 10 weight percent, or from about 4 to about 8 weight percent, or from about 5 to about 7 weight percent based on the total weight of the toner particles; a wax, in embodiments a polyethylene wax, a paraffin wax, or a combination thereof, present in an amount of from 7 to about 20 weight percent, or from about 9 to about 16 weight percent based on the total weight of the toner particles; and a core resin comprising at least one styrene-acrylate copolymer, in embodiments at least two styrenes selected from the group consisting of Styrene-Acrylate Copolymer 1, Styrene-Acrylate Copolymer 2, and Styrene-Acrylate Copolymer 3. a core resin comprising a combination of styrene-acrylate copolymers and a styrene-acrylate copolymer, the shell resin comprising at least one styrene-acrylate copolymer selected from the group consisting of styrene-acrylate copolymer 1, styrene-acrylate copolymer 2, styrene-acrylate copolymer 3, and combinations thereof, the shell resin being present in an amount of about 26 to about 30 percent, or about 26 to about 28 percent by weight, based on the total weight of the toner particle; a coagulant, in embodiments polyaluminum chloride, present in an amount of about 0.18 pph (parts per million) (based on the total weight of the toner); and a chelating agent, in embodiments ethylene diamine tetraacetic acid (EDTA), present in an amount of about 0.79 pph (parts per million) (based on the total weight of the toner). It is intended herein to describe pph based on the raw materials actually remaining in the final toner.

[0017] Core resin.

[0018] The toner core herein comprises one or a combination of styrene-acrylate copolymers. In an embodiment, the core resin comprises a first styrene-acrylate copolymer, a second styrene-acrylate copolymer, and optionally a third styrene-acrylate copolymer. The first, second, and third styrene-acrylate copolymers are different. In an embodiment, the shell resin comprises at least one styrene-acrylate copolymer, in an embodiment, a combination of two styrene-acrylate copolymers, and in a further embodiment, a combination of three styrene-acrylate copolymers. Each of the styrene-acrylate copolymers has a specific molecular weight and glass transition temperature. The styrene-acrylate copolymers are selected to provide a specific molecular weight to the overall toner. Thus, a unique combination of core latexes is described that provides the desired properties, such as toner molecular weight, glass transition temperature, melt viscosity, and triboelectric properties, to the overall toner.

[0019] In embodiments, the toner is prepared with an aggregating agent, a chelating agent, or both an aggregating agent and a chelating agent.

[0020] The amount of aggregating agent incorporated in preparing the toner is, in embodiments, from about 0.01 to about 1.00, or from about 0.05 to about 0.50, or from about 0.10 to about 0.20 parts per million (pph), based on the total weight of the dry toner particles.

[0021] The amount of chelating agent incorporated in preparing the toner is, in embodiments, from about 0.01 to about 1.50, or from about 0.50 to about 1.00, or from about 0.75 to about 0.85 parts per million (pph), based on the total weight of the dry toner particles.

[0022] In embodiments, the amount of flocculant dispensed in preparing the toner is selected to provide a residual amount of flocculant in the final toner of about 1 to about 1,000, or about 350 to about 550, or about 425 to about 475 parts per million (ppm) of flocculant based on the total weight of the toner. In the case of aluminum-based flocculants, the active ingredient in the flocculant is elemental aluminum ion. The inert counterion of the flocculant is filtered out. In the case of aluminum-based flocculants, verifying the residual flocculant in the toner can be done by testing for elemental aluminum. Thus, in embodiments, the toner is selected to provide a residual amount of aluminum in the final toner of about 1 to about 1,000, or about 350 to about 550, or about 425 to about 475 parts per million (ppm) of aluminum based on the total weight of the dry toner particles.

[0023] In embodiments, the amount of chelating agent incorporated in preparing the toner is selected to provide a residual amount of chelating agent in the final toner of from about 0 to about 8,000, or from about 10 to about 100, or from about 20 to about 50 parts per million (ppm), based on the total weight of the dry toner particles.

[0024] By selecting the coagulant, chelating agent, or a combination thereof, the desired rheological properties of the final toner can be achieved. For example, the melt viscosity as measured by the melt flow index (MFI) can be decreased by using a larger amount of the chelating agent, or can be increased by using a larger amount of the coagulant. Also, the Tg can be decreased by using a larger amount of the chelating agent.

[0025] In embodiments, the toner particles include and are prepared using various combinations of the three styrene-acrylate latexes described herein: Styrene-Acrylate Copolymer 1, Styrene-Acrylate Copolymer 2, and Styrene-Acrylate Copolymer 3.

[0026] In an embodiment, the styrene-acrylate copolymer 1 is a styrene-acrylate copolymer having a molar ratio of monomers of about 80 to about 90 parts styrene, about 10 to about 20 parts n-butyl acrylate, and about 0.5 to about 3 parts β-carboxyethyl acrylate, a weight average molecular weight (Mw) value of about 32,000 g / mol to about 38,000 g / mol, and a number average molecular weight (Mn) value of about 13,000 g / mol to about 18,000 g / mol. Both Mw and Mn can be determined using gel permeation chromatography (GPC). In an embodiment, the styrene-acrylate copolymer 1 has a glass transition temperature (Tg) in the range of about 55°C to about 65°C, about 57°C to about 64°C, or about 57°C to about 61°C. The Tg can be determined using Differential Scanning calorimetry (DSC). The onset Tg is defined as the intersection of a line tangent to the heat flow curve both before and after the glass transition.

[0027] In an embodiment, the styrene-acrylate copolymer 2 is a styrene-acrylate copolymer having a molar ratio of monomers of about 70 to about 80 parts styrene, about 20 to about 30 parts n-butyl acrylate, and about 0.5 to about 3.0 parts β-carboxyethyl acrylate, a weight average molecular weight (Mw) value of about 52,000 g / mol to about 58,000 g / mol, and a number average molecular weight (Mn) value of about 28,000 g / mol to about 33,000 g / mol. Both Mw and Mn can be determined using gel permeation chromatography (GPC). In an embodiment, the styrene-acrylate copolymer 2 has a glass transition temperature (Tg) in the range of about 50.0° C. to about 60.0° C., about 52.0° C. to about 59.9° C., or about 53.0° C. to about 57.0° C. The Tg can be determined using differential scanning calorimetry (DSC).

[0028] In an embodiment, the styrene-acrylate copolymer 3 is a styrene-acrylate copolymer having a molar ratio of monomers of about 70 to about 80 parts styrene, about 20 to about 30 parts n-butyl acrylate, and about 0.5 to about 3.0 parts β-carboxyethyl acrylate, a weight average molecular weight (Mw) value of about 33,000 g / mol to about 39,000 g / mol, and a number average molecular weight (Mn) value of about 13,000 g / mol to about 18,000 g / mol. Both Mw and Mn can be determined using gel permeation chromatography (GPC). In an embodiment, the styrene-acrylate copolymer 3 has a glass transition temperature (Tg) in the range of about 46.0° C. to about 56.0° C., about 48.0° C. to about 54.0° C., or about 49.0° C. to about 53.0° C. The Tg can be determined using differential scanning calorimetry (DSC).

[0029] In embodiments, the toner particle core resin and shell resin are selected to provide the final toner with a weight average molecular weight (Mw) of about 38,000 g / mol to about 48,000 g / mol, or about 40,000 g / mol to about 46,000 g / mol, or about 42,000 g / mol to about 45,000 g / mol, and a number average molecular weight (Mn) value of about 16,000 g / mol to about 23,000 g / mol, or about 17,000 g / mol to about 22,000 g / mol, or about 18,000 g / mol to about 21,000 g / mol. The Mw and Mn of the toner can be determined using gel permeation chromatography (GPC).

[0030] In embodiments, the toner particle core resin and shell resin are selected to provide the final toner with an onset glass transition temperature (Tg) within the range of about 53.0°C to about 60.0°C, about 54.0°C to about 58.0°C, or about 55.0°C to about 57.0°C. The Tg of the toner may be determined using differential scanning calorimetry (DSC). As previously described, the "onset Tg" is defined as the intersection of the lines tangent to both the heat flow curves before and after the glass transition. Unless otherwise noted, as used herein, both "Tg" and "onset Tg" refer to the onset glass transition temperature.

[0031] Known chain transfer agents can be utilized to control the molecular weight properties of the core and shell resin polymers. Examples of chain transfer agents include dodecanethiol, dodecyl mercaptan, octanethiol, carbon tetrabromide, carbon tetrachloride, and the like, and are present in various suitable amounts, such as about 0.1 to about 10 weight percent of the total monomers, such as about 0.1 to about 8 weight percent of the total monomers, or about 0.2 to about 5 weight percent.

[0032] In an embodiment, the toner particles have a core-shell configuration. The core comprises a combination of styrene-acrylate copolymers. In an embodiment, the core comprises a combination of a first styrene-acrylate copolymer, a second styrene-acrylate copolymer, and optionally a third styrene-acrylate copolymer, where the first core styrene-acrylate copolymer is styrene-acrylate copolymer 1, the second core styrene-acrylate copolymer is styrene-acrylate copolymer 2, and the optional third styrene-acrylate copolymer is styrene-acrylate copolymer 3. In another embodiment, the core comprises at least one of styrene-acrylate copolymer 1, styrene-acrylate copolymer 3, or a combination of styrene-acrylate copolymer 1 and styrene-acrylate copolymer 3. In another embodiment, the core comprises at least one of a combination of styrene-acrylate copolymer 2, styrene-acrylate copolymer 3, or styrene-acrylate copolymer 3. In certain embodiments, the core comprises a combination of a first styrene-acrylate copolymer and a second styrene-acrylate copolymer.

[0033] The shell comprises at least one styrene-acrylate copolymer selected from Styrene-Acrylate 1, Styrene-Acrylate 2, and Styrene-Acrylate 3, or combinations thereof. In embodiments, the shell comprises a first styrene-acrylate copolymer and a second styrene-acrylate copolymer, where the first shell styrene-acrylate copolymer is Styrene-Acrylate Copolymer 1 and the second shell styrene-acrylate copolymer is Styrene-Acrylate Copolymer 2. In certain embodiments, the shell comprises only Styrene-Acrylate Copolymer 1.

[0034] Thus, in an embodiment, the toner particles have a core-shell structure, the core comprises a first, second, and optional third styrene-acrylate copolymer, the first core styrene-acrylate copolymer is Styrene-acrylate Copolymer 1, the second core styrene-acrylate copolymer is Styrene-acrylate Copolymer 2, and the optional third styrene-acrylate copolymer is Styrene-acrylate Copolymer 3, and the shell comprises a first and a second styrene-acrylate copolymer, the first shell styrene-acrylate copolymer is Styrene-acrylate Copolymer 1, and the second shell styrene-acrylate copolymer is Styrene-acrylate Copolymer 2. Further, in this embodiment, the core may include a colorant comprising a combination of carbon black and a cyan pigment.

[0035] In another embodiment, the toner particles have a core-shell structure, the core comprises one or a combination of styrene-acrylate copolymer 1 and styrene-acrylate copolymer 3, and the shell comprises one or a combination of styrene-acrylate copolymer 1, styrene-acrylate copolymer 2, and styrene-acrylate copolymer 3. In an embodiment, the core comprises styrene-acrylate copolymers 1 and 3, and the shell comprises a single styrene-arylate copolymer 1. In another embodiment, the core comprises styrene-acrylate copolymers 1 and 3, and the shell is styrene-acrylate copolymer 2. In another embodiment, the core comprises styrene-acrylate copolymers 2 and 3, and the shell is styrene-acrylate copolymer 2. In yet another embodiment, the core comprises styrene-acrylate copolymer 3, and the shell comprises styrene-acrylate copolymer 1. In yet another embodiment, the core comprises styrene-acrylate copolymer 3, and the shell comprises styrene-acrylate copolymer 2. In another embodiment, the core comprises Styrene-Acrylate Copolymer 3 and the shell comprises Styrene-Acrylate Copolymer 3. In a particular embodiment, the toner particles have a core-shell structure, the core comprises a combination of Styrene-Acrylate Copolymer 1 and Styrene-Acrylate Copolymer 2, and the shell comprises only Styrene-Acrylate Copolymer 1. Further, in embodiments, the core may include a colorant comprising at least one of black, carbon black, cyan, magenta pigment, and yellow pigment, in embodiments copper phthalocyanine, PR122, PR269, PY74, or combinations thereof.

[0036] The toner particle core may include a styrene-acrylate copolymer as described herein, and a combination of a colorant and a wax as described herein. Once the core particle is formed and aggregated to a desired size, a thin outer shell is then formed on the core particle. The shell may consist of one or a combination of styrene-acrylate copolymers as described herein.

[0037] The shell latex may be added to the core toner particle aggregates in any suitable or desired amount, and in embodiments, the shell latex may be added to the core toner particle aggregates in an amount of from about 20 to about 45 weight percent of the total binder material (i.e., the sum of the core latex and the shell latex), or from about 25 to about 40 weight percent, or from about 30 to about 235 weight percent, based on the total weight of the binder material (the core latex and the shell latex combined).

[0038] In embodiments, the toner comprises from about 50 to about 60 weight percent core resin, or from about 52 to about 56 weight percent core resin, from about 26 to about 30 weight percent shell resin, or from about 26 to about 28 weight percent shell resin, from about 3 to about 10 weight percent colorant, or from about 4 to about 8 percent, or from about 5 to about 7 percent colorant, from about 7 to about 20 weight percent wax, or from about 9 to about 16 percent wax, where the percentages are weight percent based on the total weight of the toner.

[0039] The total amount of binder, including the core resin and the shell resin, can be from about 60 to about 95 percent by weight of the toner particle (ie, the toner particle excluding external additives), or from about 70 to about 90 percent by weight of the toner particle.

[0040] In embodiments, the polymers for the core and shell binders may each be formed into a latex for use in a subsequent emulsion aggregation toner particle formation process. Such may be done by mixing the monomer components, including any additives, in an aqueous phase, optionally in the presence of one or more surfactants, and then polymerizing the monomers, for example using an initiator, to form small sized seed particles. For example, a latex is obtained having an aqueous phase containing small sized polymer particles, for example, from about 5 nanometers (nm) to about 500 nm, or from about 50 nm to about 300 nm. Any suitable method for forming a latex from the monomers may be used. The latex particle size is given as the volume average median particle diameter measured using a Nanotrac particle size analyzer. "Nanotrac" is the model name of a particle size analyzer made by Microtrac. It uses dynamic light scattering technology.

[0041] A variety of suitable colorants may be used, including suitable color pigments, dyes, and mixtures thereof. Examples of suitable colorants include carbon black, such as REGAL® 330 carbon black, acetylene black, lamp black, aniline black, chrome yellow, zinc yellow, SICOFAST yellow, SUNBRITE® yellow, LUNA yellow, NOVAPERM® yellow, PY74 (monoazo yellow), chrome orange, BAYPLAST® orange, cadmium red, LITHOL® scarlet, HOSTAPERM red, PR122 (quinacridone red or pigment red 122), PR269 (naphthol red, FANAL® pink, HOSTAPERM® pink, LUPRETON pink, LITHOL red, RHODAMINE Lake B, brilliant carmine, HELIOGEN® blue, HOSTAPERM® blue, NEOPAN® blue, PV Fast® Blue, copper phthalocyanine, CINQUASSI® Green, HOSTAPERM® Green, titanium dioxide, cobalt, nickel, iron powder, iron oxides such as SICOPUR 4068 FF, and MAPICO® Black (Columbia), NP608 and NP604 (Northern Pigment), BAYFERROX® 8610 (Bayer), and M08699 (Mobay), TMB-100 (Magnox), mixtures thereof, and the like.

[0042] In an embodiment, the optional colorant is present and is selected from cyan, magenta, yellow, black, or a combination thereof. Carbon black may be used with one or more other colorants, such as a cyan colorant, to produce a desired hue. In an embodiment, the optional colorant is present and includes a combination of a cyan pigment and carbon black. In a further embodiment, the optional colorant is present and includes a combination of carbon black, copper phthalocyanine, magenta, and yellow, in an embodiment, the magenta is pigment red and the yellow is pigment yellow.

[0043] The colorant may be included in any suitable or desired amount. In embodiments, the colorant, e.g., carbon black, cyan, magenta, and / or yellow colorant, is incorporated in an amount sufficient to impart the desired color to the toner. Generally, the pigment or dye is used in an amount of about 2 weight percent to about 35 weight percent of the toner particles, e.g., about 2 weight percent to about 25 weight percent, or about 2 weight percent to about 20 weight percent of the toner particles, calculated on a solids basis. In certain embodiments, the colorant is included in an amount of about 3 to about 10 weight percent total colorant, based on the total weight of the toner particles, the total colorant including a combination of black and cyan colorants, in embodiments, carbon black and cyan. In embodiments, the colorant includes a combination of carbon black and cyan, the carbon black being included in an amount of about 1 to about 25, or about 4 to about 10, or about 5 to about 7 percent carbon black, and the cyan being included in an amount of about 0 to about 3, or about 0.5 to about 2 percent cyan.

[0044] The colorant may be in the form of an aqueous emulsion or dispersion of colorant in water, optionally using a surfactant, such as an anionic or nonionic surfactant, for incorporation into the toner, and the colorant is, in embodiments, a pigment having a particle size of from about 50 nanometers (nm) to about 3,000 nm, or from about 100 nm to about 2,000 nm, or from about 50 nm to about 1,000 nm. Pigment particle size is given as the volume average median particle diameter measured using a Nanotrac particle size analyzer.

[0045] Anionic surfactants include sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate, sodium dodecylnaphthalene sulfate, dialkylbenzene alkyl sulfates and sulfonates, abietic acid, and NEOGEN® brand anionic surfactants. Examples of suitable anionic surfactants are NEOGEN® RK available from Daiichi Kogyo Seiyaku co. Ltd., or TAYCA POWER BN2060 from Tayca Corporation (Japan), which is composed primarily of branched sodium dodecylbenzenesulfonate. The effective concentration of anionic surfactants typically used is, for example, about 0.01 to about 10 weight percent, or about 0.1 to about 5 weight percent, based on the weight of the dispersion.

[0046] Examples of cationic surfactants include dialkylbenzene alkyl ammonium chloride, lauryl trimethyl ammonium chloride, alkyl benzyl methyl ammonium chloride, alkyl benzyl dimethyl ammonium bromide, benzalkonium chloride, ethyl pyridinium bromide, C12, C15, C17 trimethyl ammonium bromide, halide salts of quaternized polyoxyethyl alkyl amines, dodecyl benzyl triethyl ammonium chloride. MIRAPOL® and ALKAQUAT® available from Alkaril Chemical Company, SANISOL® (benzalkonium chloride) available from Kao Chemicals, and the like. An example of a suitable cationic surfactant is SANISOL® B-50 available from Kao Corp., which consists primarily of benzyl dimethyl alkonium chloride. The effective concentration of cationic surfactants commonly used is, for example, about 0.01 to about 10 weight percent, or about 0.1 to about 5 weight percent, based on the weight of the dispersion.

[0047] Examples of nonionic surfactants include polyvinyl alcohol, polyacrylic acid, methalose, methylcellulose, ethylcellulose, propylcellulose, hydroxyethylcellulose, carboxymethylcellulose, polyoxyethylene cetyl ether, polyoxyethylene lauryl ether, polyoxyethylene octyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene sorbitan monolaurate, polyoxyethylene stearyl ether, polyoxyethylene nonylphenyl ether, dialkylphenoxypoly(ethyleneoxy)ethanol available from Rhone-Poulenc Inc. as IGEPAL® CA-210, IGEPAL® CA-520, IGEPAL® CA-720, IGEPAL® CO-890, IGEPAL® CO-720, IGEPAL® CO-290, IGEPAL® CA-210, ANTAROX® 890, and ANTAROX® 897. An example of a suitable nonionic surfactant is ANTAROX® 897, which is composed primarily of alkylphenol ethoxylates, available from Rhone-Poulenc Inc. Effective concentrations of nonionic surfactants typically used are, for example, from about 0.01 to about 10 weight percent, or from about 0.1 to about 5 weight percent, based on the weight of the dispersion.

[0048] In addition to the polymer binder (styrene-acrylate resin) and colorant, the toner may further comprise a wax, in embodiments used in the form of a wax dispersion, to form the toner. Waxes may be included in the toner formulation to aid in the offset resistance of the toner, for example, toner release from the fuser roll, especially in low-oil or no-oil fuser designs.

[0049] Waxes that may be selected include, for example, polyolefins such as polymethylene, polyethylene, polypropylene, polybutene, and waxes made by the Fischer-Tropsch process. In embodiments, the toner comprises a wax selected from a member of the group consisting of Fischer-Tropsch wax, polyethylene wax, paraffin wax, and combinations thereof. In embodiments, the wax is a Fischer-Tropsch wax. In other embodiments, the wax is a paraffin wax. In yet other embodiments, the wax is a polyethylene wax. In still further embodiments, the wax comprises a combination of a paraffin wax and one or more Fischer-Tropsch waxes.

[0050] In an embodiment, the wax is a linear Fischer-Tropsch wax derived from carbon monoxide or other low molecular weight feedstocks, such as those produced by Sasol or Shell-Malaysia. The wax may have a peak melting temperature, measured using differential scanning calorimetry, of from about 70° C. to about 100° C., or from about 85° C. to about 95° C.

[0051] In embodiments, the wax is a straight chain hydrocarbon having from about 46 to about 56 carbon atoms and a peak melting temperature of from about 88°C to about 100°C.

[0052] In embodiments, the wax is a polyethylene wax having a peak melting temperature of from about 85°C to about 110°C, or from about 95°C to about 105°C.

[0053] Any suitable or desired paraffin wax may be selected for the embodiments herein. In embodiments, the paraffin wax may be BW-422 and BW-436 (from Blended Waxes, Inc.); IGI 1245A, IGI 1250A, IGI 1297A, IGI 1266A (all from the International Group, Inc.); Indrawax 6062-F, Indrawax 6264-F, Indrawax 6466-F, Indrawax 6668-F, Indrawax 6870-F, Indrawax 7072-F, Indrawax 8070, Indrawax 6062-S 140-144, Indrawax 6062-S (all from Industrial Raw Materials LLC); Shell Sarawax SX70 (Alpha Wax from Strahl & Pitsch; 434 and 674 paraffin waxes from Strahl & Pitsch; dispersions of paraffin wax including CHEMBEAD® 30, CHEMBEAD® 30-AM, PARAFINE 30, PARAFFIN 60, PARAFFIN EMULSION 135-45 FDA, PARAFFIN EMULSION 150-45 FDA (all from BYK Additives & Instruments); and combinations thereof.

[0054] For incorporation of the wax into the toner, the wax may be in the form of an aqueous emulsion or an aqueous dispersion of solid wax, the particle size of the solid wax typically being in the range of about 100 to about 500 nm, where particle size refers to the volume average median particle diameter measured using a Nanotrac particle size analyzer using dynamic light scattering technology.

[0055] In embodiments, the toner comprises from about 3.5 to about 20 weight percent, or from about 5 to about 20 weight percent, or from about 7 to about 20 weight percent, or from about 9 to about 16 weight percent of wax, based on the weight of the toner.

[0056] The toner herein may also contain a flocculating or coagulating agent, such as a monovalent metal coagulating agent, a divalent metal coagulating agent, a polyionic coagulating agent, etc. A variety of coagulating agents are known in the art. As used herein, "polyionic coagulating agent" refers to a coagulating agent that is a salt or oxide, such as a metal salt or metal oxide, formed from a metal species having a valence of at least 3, preferably at least 4 or 5. Thus, suitable coagulating agents include aluminum-based coagulating agents, such as polyaluminum halides, such as polyaluminum fluoride and polyaluminum chloride (PAC), polyaluminum silicates, such as polyaluminum sulfosilicate (PASS), polyaluminum hydroxide, and polyaluminum phosphate. Other suitable coagulants include, but are not limited to, tetraalkyl titanates, dialkyl tin oxides, tetraalkyl tin oxide hydroxides, dialkyl tin oxide hydroxides, aluminum alkoxides, alkyl zincs, dialkyl zincs, zinc oxides, tin oxides, dibutyl tin oxides, dibutyl tin oxide hydroxides, tetraalkyl tins, combinations thereof, and the like. When the coagulant is a polyion coagulant, the coagulant can have any desired number of polyion atoms present. For example, in embodiments, suitable polyaluminum compounds can have from about 2 to about 13, or from about 3 to about 8 aluminum ions present in the compound. In embodiments, polyaluminum chloride coagulants are selected.

[0057] Such coagulants can be incorporated into the toner particles during particle aggregation. Thus, the coagulant can be present in the toner particles in an amount of about 0 to about 5 percent by weight, or about 0 to about 3 percent by weight, of the toner particles, excluding external additives, on a dry weight basis. In embodiments, the coagulant (or coagulant) is used in an amount of about 0.18 pph, based on the total weight of the toner.

[0058] For high gloss, the presence of aluminum metal and / or metal ions in the final toner particles is undesirable as aluminum inhibits the obtainable gloss (higher aluminum content leads to lower gloss of the toner, e.g. due to crosslinking), therefore aluminum needs to be substantially extracted from the formed toner particles. Such extraction can be done by any suitable method, but in embodiments the method comprises adding a chelating or sequestering agent to the aggregated toner particles to extract the aluminum ions therefrom in a controlled manner, i.e. such that the final content of aluminum present in the toner can be controlled. As the sequestering or chelating agent, in embodiments ethylenediaminetetraacetic acid (EDTA), commercially available as VERSENE® 100, sodium silicate solution, and the like, can be selected.

[0059] The chelating or sequestering agent may be added in an amount effective to extract aluminum ions from solution such that the final aluminum content in the toner is less than about 1,000 ppm, for example from about 1 ppm to about 1,000 ppm, or from about 350 ppm to about 550 ppm, or from about 425 ppm to about 475 ppm, based on the total weight of the toner, where ppm is parts per million. The amount of chelating or sequestering agent added may be from about 0.01 to about 10 percent by weight of the solution, the solution being 39 percent by weight, or from about 0.01 to about 5 percent, or from about 0.5 to about 5 percent active chelating agent, based on the total weight of the toner. In embodiments, the chelating agent, in embodiments EDTA, is selected in an amount of about 0.79 pph, based on the total weight of the dry toner particles, where pph is a percentage.

[0060] In embodiments, the chelating or sequestering agent is substantially absent in the final toner and is therefore added in an amount substantially equal to that required to achieve the aforementioned amounts of aluminum in the final toner, and not substantially exceeding such amount so that excess sequestering or chelating agent is not retained in the toner.

[0061] The chelating or sequestrant may be added near the end of the aggregation step in the emulsion aggregation toner particle formation process, although such extraction may also occur at any time following aggregation and prior to any coalescence step.

[0062] Optionally, the toner particles may contain other optional additives. For example, the toner may contain a positive or negative charge control agent in any desired or effective amount, in embodiments at least about 0.1 weight percent of the toner, or at least about 1 weight percent of the toner, or up to about 10 weight percent of the toner, or up to about 3 weight percent of the toner. Examples of suitable charge control agents include, but are not limited to, quaternary ammonium compounds such as alkylpyridinium halides, bisulfates, alkylpyridinium compounds, including those disclosed in U.S. Pat. No. 4,298,672, which is incorporated herein by reference in its entirety, organic sulfate and sulfonate compositions, including those disclosed in U.S. Pat. No. 4,338,390, which is incorporated herein by reference in its entirety, cetylpyridinium tetrafluoroborate, distearyl dimethyl ammonium methyl sulfate, aluminum salts such as BONTRON E84™ or E88™ (Hodogaya Chemical), and the like, and mixtures thereof. Such charge control agents may be applied simultaneously with the shell resin or after application of the shell resin.

[0063] When preparing toners by emulsion aggregation procedures, one or more surfactants may be used during the process. Suitable surfactants include the anionic, cationic, and nonionic surfactants described above.

[0064] Any suitable emulsion aggregation procedure may be used in forming the emulsion aggregation toner particles. These procedures typically include the basic process steps of at least aggregating an aqueous latex emulsion containing a binder polymer, a colorant, a wax, optionally one or more surfactants, a coagulant, and any additional optional additives to form aggregates, optionally forming a shell on the aggregate core particles by adding a latex of a shell material, optionally extracting metal (aluminum) from the particles, optionally subsequently coalescing or fusing the aggregates, and then recovering, optionally washing, and optionally drying the resulting emulsion aggregation toner particles.

[0065] In an embodiment, a method of preparing a toner, including emulsion aggregation core-shell toner particles, includes obtaining a core styrene-acrylate copolymer latex, an optional aqueous dispersion of a colorant, and an aqueous dispersion of a wax, forming a mixture of the core styrene-acrylate copolymer latex, the optional aqueous dispersion of a colorant, and the aqueous dispersion of a wax, heating the mixture to a first temperature, maintaining the first temperature to form aggregate toner particles, adding a shell styrene-acrylate copolymer latex to form a shell on the aggregate particles, optionally adding a solution of a chelating agent, stopping further aggregation and increasing the temperature to a second temperature higher than the first temperature to coalesce the aggregate particles, and subsequently cooling and optionally washing and recovering the emulsion aggregation toner particles.

[0066] In certain embodiments, the toner herein comprises emulsion aggregation toner particles comprising a core and a shell thereon, the core comprising a combination of at least two styrene-acrylate copolymers selected from a first core styrene-acrylate copolymer, a second styrene-acrylate copolymer, and a third styrene-acrylate copolymer, a wax, and an optional colorant, the first core styrene-acrylate copolymer being a combination of at least two styrene-acrylate copolymers selected from a first core styrene-acrylate copolymer, a second core styrene-acrylate copolymer, and a third ... The first core styrene-acrylate copolymer has a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0° C. to about 61.0° C., the second core styrene-acrylate copolymer has a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0° C. to about 57.0° C., and the third core styrene-acrylate copolymer has a weight average molecular weight of about 33,000 g / mol to about 39,000 g / mol. and an onset glass transition temperature of about 49.0° C. to about 53.0° C., and the shell comprises at least one styrene-acrylate copolymer selected from a first shell styrene-acrylate copolymer, a second shell styrene-acrylate copolymer, or a combination thereof, and the first shell styrene-acrylate copolymer has a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0° C. to about 61.0° C. and the second shell styrene-acrylate copolymer has a weight average molecular weight of from about 52,000 g / mol to about 58,000 g / mol, and an onset glass transition temperature of from about 53.0° C. to about 57.0° C., the toner comprising from about 50 to about 60 weight percent core, from about 26 to about 30 weight percent shell, from about 3 to about 10 weight percent colorant, and from about 7 to about 20 weight percent wax, based on the total weight of the toner.

[0067] In embodiments, the toner particles have a volume average median particle diameter of from about 1 to about 15 micrometers, or from about 2 to about 10 micrometers, or from about 4 to about 9 micrometers, as measured using a Coulter Counter Multisizer 3. In embodiments, the toner particles have an average circularity of from about 0.93 to about 0.98, as measured using a Malvern Sysmex Flow Particle Image Analyzer (FPIA3000). Circularity is a measure of a particle's closeness to a perfect sphere. A circularity of 1.0 identifies a particle having the shape of a perfect round sphere.

[0068] The cohesion of a toner particle is in part related to the surface morphology of the particle: the rounder / smoother the surface of the particle, the lower the cohesion and the greater the flow; the less rounded / rougher the surface, the worse the flow and the more cohesion.

[0069] The toner particles may also have a size distribution such that the volume geometric standard deviation (GSDv) of (D84 / D50) is within the range of about 1.15 to about 1.25. The volume average particle diameter at which a cumulative percentage of 50% of the total toner particles is achieved is defined as a volume D50 of 5, and the volume average particle diameter at which a cumulative percentage of 84% is achieved is defined as a volume D84. These above volume average particle size distribution indices GSDv can be expressed by using D50 and D84 in the cumulative distribution, and the volume average particle size distribution index GSDv is expressed as (volume D84 / volume D50). The GSDv value of the toner particles indicates that the toner particles are made to have a very narrow particle size distribution.

[0070] The toner particles may also be blended with external additive particles, including flow aid additives, which may be present on the surface of the toner particles. Examples of these additives include, but are not limited to, metal oxides, such as titanium oxide, silicon oxide, tin oxide, and mixtures thereof, colloidal and non-crystalline silicas, such as AEROSIL®, metal salts, and metal salts of fatty acids, including zinc stearate, aluminum oxide, cerium oxide, and mixtures thereof. Each of these external additives may be present in any desired or effective amount, in embodiments at least about 0.1 weight percent of the toner, or at least about 0.25 weight percent of the toner, or up to about 5 weight percent of the toner, or up to about 3 weight percent of the toner. Suitable additives include, but are not limited to, those disclosed in U.S. Pat. Nos. 3,590,000 and 6,214,507, each of which is incorporated herein by reference. Such additives may be applied simultaneously with the shell resin or after application of the shell resin.

[0071] The toner of the present invention may be formulated into a developer composition. The developer composition can be prepared by mixing the toner of the present disclosure with known carrier particles, including coated carriers such as steel, ferrite, etc. Such carriers include those disclosed in U.S. Pat. Nos. 4,937,166 and 4,935,326, the entire disclosures of each of which are incorporated herein by reference.

[0072] The toner may be present in the carrier in an amount of about 1% to about 15% by weight, about 2% to about 8% by weight, or about 4% to about 6% by weight. The carrier particles may also include a core having a polymer coating, such as polymethylmethacrylate (PMMA), in which a conductive component, such as conductive carbon black, is dispersed. Carrier coatings include silicone resins, such as methylsilsesquioxane, fluoropolymers, such as polyvinylidene fluoride, mixtures of resins that are not adjacent in the triboelectric series, such as polyvinylidene fluoride and acrylic, thermosetting resins, such as acrylic, combinations thereof, and other known components.

[0073] The toner of the present invention may be used in a variety of electrophotographic processes and with a variety of electrophotographic printers. The electrophotographic imaging process includes, for example, preparing an image in an electrophotographic printer that includes a charging component, an imaging component, a photoconductive component, a developing component, a transfer component, and a fusing component. In embodiments, the developing component may include a developer prepared by mixing a carrier with any of the toners described herein. The electrophotographic printer may include high speed printers, black and white high speed printers, color printers, and the like. Once an image is formed with the toner / developer, the image may then be transferred to an image receiving medium, such as paper. A fuser roll member may be used to fuse the toner to the image receiving medium by using heat and pressure. The use of the toner of the present invention in an electrophotographic printing process can provide printed images having the properties described herein and other desirable properties.

[0074] Toners of the present invention find use in other applications such as powder coating applications in which a powder spray gun (eg, a tribo gun) containing any of the toners of the present invention is used to deliver the toner to a substrate.

[0075] In embodiments, the process herein includes forming an image with the toner described herein using an electrophotographic printer, transferring the image including the toner to an image receiving medium, and fusing the toner to the image receiving medium to form a toner image. EXAMPLES

[0076] The following examples are presented to further define the various species of the present disclosure. These examples are intended to be illustrative only and are not intended to limit the scope of the present disclosure. Also, unless otherwise stated, parts and percentages are by weight.

[0077] The toner was prepared using an aggregation / coalescence process as follows.

[0078] 1. The core materials (latex, pigment, wax) and deionized water were mixed in a gallon reactor.

[0079] 2. The reactor contents were homogenized using a rotor / stator homogenizer and polyaluminum chloride flocculant was added.

[0080] 3. The reactor was heated to 52°C-59°C for agglomeration. The stirring speed was set depending on the slurry viscosity. The particle size (D50v) was monitored using a Coulter Multisizer-3 instrument.

[0081] 4. Once a pre-shell particle size of approximately 5.3 micrometers was achieved, the shell latex was added to the reactor using a metering pump.

[0082] 5. The pH of the slurry was increased to 4.5-5.7 by adding NaOH solution and Versene™ 100 solution. The stirring speed was gradually decreased depending on the viscosity. The batch was then held for 10 minutes.

[0083] 6. The reactor was heated to about 80° C. HNO3 solution was added to the reactor to achieve a pH of 4.0-5.2. The reactor was then heated to a coalescence temperature of 92.0-98.0° C.

[0084] 7. The reactor was held at the coalescence temperature until a circularity of 0.970-0.975 was achieved. Circularity was monitored using an FPIA Sysmex 3000 instrument.

[0085] 8. NaOH solution was then added to raise the pH to 6.0. The reactor was then cooled to below 63° C. and the pH was further raised to 8.8 using 1M NaOH. The reactor was then cooled to room temperature.

[0086] 9. The contents of the reactor were collected and then sieved, washed and dried using conventional methods.

[0087] The material properties table is as follows: In Table 2, Sty-A1 refers to Styrene-Acrylate Copolymer 1, Sty-A2 refers to Styrene-Acrylate Copolymer 2, and Sty-A3 refers to Styrene-Acrylate Copolymer 3, as described herein. [Table 1] [Table 2] [Table 3]

[0088] The toner properties can be fine-tuned by changing the type and amount of raw materials used in the aggregation / coalescence process. The overall toner molecular weight (Mw) and glass transition temperature (Tg) can be influenced by the core latex and shell latex. The examples show various combinations of three styrene-acrylate latexes, each with its own Tg and Mw. The toner composition was geared towards increasing Tg and increasing Mw to improve the storage stability and durability of the toner. The different latex compositions selected for the particle core and particle shell are selected to further optimize the toner properties. Higher Tg and Mw in the shell are generally preferred to improve storage stability and durability, while lower Tg and Mw in the core are generally preferred to improve gloss and low melt properties.

[0089] Wax formulations can have a significant effect on toner melting properties. Low melting waxes, such as paraffin, lead to increased melt flow (lower T1 / 2) and decreased Tg. Waxes can also affect other machine performance metrics, such as hot offset and fine particle release. In embodiments, the type and amount of wax is selected to affect these properties.

[0090] Aluminum complexes used as flocculants can also affect toner melting properties. Residual aluminum can crosslink the coalescing resin, causing a decrease in melt flow. This can result in a decrease in floss and fixation properties. Although a minimum amount of flocculant is desired to promote flocculation, a chelating agent can be added during the freezing step to remove excess aluminum.

[0091] In an embodiment, two levels of pigment loading were chosen to observe the range of dielectric loss and optical density due to carbon black.

[0092] Particle size and shape affect many electrophotographic properties such as Tribo, flow, and transferability. The toner composition allows for a wide range of toner sizes and shapes that meets the machine requirements and provides the desired toner properties. [Table 4]

[0093] A toner particle composition was prepared containing the following ingredients: Examples 9-22, having the ingredients shown in Table 5 below, were prepared by the process described above. [Table 5]

[0094] The properties of Examples 9 to 22 are shown in Tables 6 and 7. [Table 6] [Table 7]

[0095] It will be understood that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also, various presently unanticipated or unprecedented alternatives, modifications, variations, or improvements may occur to those skilled in the art, which are also intended to be encompassed by the following "claims." Unless specifically recited in the claims, no particular order, number, position, size, shape, angle, color, or material of the steps or components of the claims should be implied or implied from this specification or any other claim. Yet another aspect of the present invention may be as follows. [1] A toner comprising toner particles including a core and a shell thereon, the core comprises at least one styrene-acrylate copolymer selected from a first core styrene-acrylate copolymer, a second core styrene-acrylate copolymer, and a third core styrene-acrylate copolymer, or combinations thereof; a wax; and an optional colorant; the first core styrene-acrylate copolymer has a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0° C. to about 61.0° C.; the second core styrene-acrylate copolymer has a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0° C. to about 57.0° C.; the third core styrene-acrylate copolymer has a weight average molecular weight of about 33,000 g / mol to about 39,000 g / mol and an onset glass transition temperature of about 49.0° C. to about 53.0° C.; the shell comprises at least one styrene-acrylate copolymer selected from a first shell styrene-acrylate copolymer, a second shell styrene-acrylate copolymer, a third shell styrene-acrylate copolymer, or a combination thereof; the first shell styrene-acrylate copolymer has a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0° C. to about 61.0° C.; the second shell styrene-acrylate copolymer has a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0° C. to about 57.0° C.; the third shell styrene-acrylate copolymer has a weight average molecular weight of about 33,000 g / mol to about 39,000 g / mol and an onset glass transition temperature of about 49.0° C. to about 53.0° C. [2] The toner comprises, based on the total weight of the toner, about 50 to about 80 weight percent of a core; about 20 to about 36 weight percent shell; about 3 to about 10 weight percent colorant; The toner according to claim 1, further comprising about 5 to about 20 weight percent of a wax. [3] The toner core comprises a combination of the first core styrene-acrylate copolymer having a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0° C. to about 61.0° C. and the second core styrene-acrylate copolymer having a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0° C. to about 57.0° C.; The toner according to [1] above, wherein the toner shell comprises a single styrene-acrylate copolymer, and the single styrene-acrylate copolymer is the first shell styrene-acrylate copolymer having a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0° C. to about 61.0° C. [4] The toner core comprises a combination of the first core styrene-acrylate copolymer having a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0° C. to about 61.0° C. and the third core styrene-acrylate copolymer having a weight average molecular weight of about 33,000 g / mol to about 39,000 g / mol and an onset glass transition temperature of about 49.0° C. to about 53.0° C.; The toner according to [1] above, wherein the toner shell comprises a single styrene-acrylate copolymer, and the single styrene-acrylate copolymer is the first shell styrene-acrylate copolymer having a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0° C. to about 61.0° C. [5] The core comprises a combination of the second core styrene-acrylate copolymer having a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0 ° C. to about 57.0 ° C. and the third core styrene-acrylate copolymer having a weight average molecular weight of about 33,000 g / mol to about 39,000 g / mol and an onset glass transition temperature of about 49.0 ° C. to about 53.0 ° C.; The toner according to [1] above, wherein the shell is a second shell styrene-acrylate copolymer having a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0° C. to about 57.0° C. [6] The core comprises the third core styrene-acrylate copolymer having a weight average molecular weight of about 33,000 g / mol to about 39,000 g / mol and an onset glass transition temperature of about 49.0 ° C to about 53.0 ° C; The toner according to [1] above, wherein the shell comprises the first shell styrene-acrylate copolymer having a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0° C. to about 61.0° C. [7] The core comprises the third core styrene-acrylate copolymer having a weight average molecular weight of about 33,000 g / mol to about 39,000 g / mol and an onset glass transition temperature of about 49.0 ° C to about 53.0 ° C; The toner according to [1] above, wherein the shell comprises the third shell styrene-acrylate copolymer having a weight average molecular weight of about 33,000 g / mol to about 39,000 g / mol and an onset glass transition temperature of about 49.0° C. to about 53.0° C. [8] The core comprises the third core styrene-acrylate copolymer having a weight average molecular weight of about 33,000 g / mol to about 39,000 g / mol and an onset glass transition temperature of about 49.0 ° C to about 53.0 ° C; The toner according to [1] above, wherein the shell is a second shell styrene-acrylate copolymer having a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0° C. to about 57.0° C. [9] The toner according to [1], wherein the core comprises a combination of the first core styrene-acrylate copolymer having a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0°C to about 61.0°C, and the second core styrene-acrylate copolymer having a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0°C to about 57.0°C.

[10] The toner according to [1], wherein the shell contains the first styrene-acrylate copolymer having a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0°C to about 61.0°C.

[11] The toner according to [1], wherein the wax is selected from the group consisting of polyethylene waxes, paraffin waxes, Fischer-Tropsch waxes, and combinations thereof.

[12] The toner according to [1] above, wherein the wax is a Fischer-Tropsch wax having a peak melting temperature of about 70°C to about 100°C.

[13] The toner according to [1] above, wherein the wax is a paraffin wax.

[14] The toner according to [1] above, wherein the wax is a polyethylene wax.

[15] The toner according to [1], wherein the optional colorant is present and is selected from cyan, magenta, yellow, black, or combinations thereof.

[16] The toner according to [1], wherein the optional colorant is present and the colorant comprises a combination of a cyan pigment and carbon black.

[17] The toner according to [1], further comprising a coagulant, a chelating agent, or a combination thereof.

[18] A method for preparing a toner, including emulsion aggregation core-shell toner particles, comprising: the core comprises at least one styrene-acrylate copolymer selected from a first styrene-acrylate copolymer, a second styrene-acrylate copolymer, and a third styrene-acrylate copolymer, or combinations thereof; a wax; and an optional colorant; the first styrene-acrylate copolymer has a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0° C. to about 61.0° C.; the second styrene-acrylate copolymer has a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0° C. to about 57.0° C.; the third styrene-acrylate copolymer has a weight average molecular weight of about 33,000 g / mol to about 39,000 g / mol and an onset glass transition temperature of about 49.0° C. to about 53.0° C.; the shell comprises at least one styrene-acrylate copolymer selected from the first styrene-acrylate copolymer, the second styrene-acrylate copolymer, the third styrene-acrylate copolymer, or a combination thereof; The method further comprising: obtaining a latex of a core styrene-acrylate copolymer, an aqueous dispersion of said optional colorant, and an aqueous dispersion of said wax; forming a mixture of the latex of a core styrene-acrylate copolymer, the aqueous dispersion of the optional colorant, and the aqueous dispersion of the wax; heating the mixture to a first temperature; maintaining said first temperature to form aggregate toner particles; adding a latex of a shell styrene-acrylate copolymer to form a shell on the agglomerated particles; Optionally, adding a solution of a chelating agent; stopping further aggregation and increasing the temperature to a second temperature greater than the first temperature to coalesce the aggregated particles. followed by cooling and optionally washing and recovering the emulsion aggregation toner particles.

[19] The toner core comprises a combination of the first styrene-acrylate copolymer having a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0° C. to about 61.0° C. and the second core styrene-acrylate copolymer having a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0° C. to about 57.0° C.; 19. The method of claim 18, wherein the toner shell comprises a single styrene-acrylate copolymer, the single shell styrene-acrylate copolymer being the first styrene-acrylate copolymer having a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0° C. to about 61.0° C.

[20] The wax is selected from the group consisting of Fischer-Tropsch wax, polyethylene wax, paraffin wax, and combinations thereof; 19. The method of claim 18, wherein the optional colorant is present and is selected from cyan, magenta, yellow, black, carbon black, copper phthalocyanine, PR122, PR269, PY74, or combinations thereof.

Claims

1. A toner comprising toner particles comprising a core and a shell thereon, the core comprises a first core styrene-acrylate copolymer and a second core styrene-acrylate copolymer, a wax, and an optional colorant; the first core styrene-acrylate copolymer is a styrene-n-butyl acrylate-β-carboxyethyl acrylate copolymer having a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0° C. to about 61.0° C.; the second core styrene-acrylate copolymer is a styrene-n-butyl acrylate-β-carboxyethyl acrylate copolymer having a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0° C. to about 57.0° C.; the shell comprises a single styrene-acrylate copolymer; the single shell styrene-acrylate copolymer is a first styrene-n-butyl acrylate-β-carboxyethyl acrylate copolymer having a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0°C to about 61.0°C.

2. The toner comprises, based on a total weight of the toner, about 50 to about 80 weight percent of a core; about 20 to about 36 weight percent of a shell; about 3 to about 10 weight percent colorant; 10. The toner of claim 1 comprising from about 5 to about 20 percent by weight of the wax.

3. A toner comprising toner particles including a core and a shell thereover, the core comprising a combination of a first core styrene-n-butyl acrylate-β-carboxyethyl acrylate copolymer having a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol, and an onset glass transition temperature of about 57.0°C to about 61.0°C, and a second core styrene-n-butyl acrylate-β-carboxyethyl acrylate copolymer having a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol, and an onset glass transition temperature of about 53.0°C to about 57.0°C.

4. 2. The toner of claim 1, wherein said wax is selected from a member of the group consisting of polyethylene waxes, paraffin waxes, Fischer-Tropsch waxes, and combinations thereof.

5. 2. The toner of claim 1, wherein said wax is a Fischer-Tropsch wax having a peak melting temperature of from about 70°C to about 100°C.

6. 2. The toner of claim 1, wherein the wax is a paraffin wax.

7. 2. The toner of claim 1, wherein the wax is a polyethylene wax.

8. 10. The toner of claim 1, wherein said optional colorant is present and said colorant is selected from cyan, magenta, yellow, black, or combinations thereof.

9. The toner of claim 1 , wherein said optional colorant is present and said colorant comprises a combination of a cyan pigment and carbon black.

10. The toner of claim 1 further comprising a coagulant, a chelating agent, or a combination thereof.

11. The toner of claim 1, having an onset glass transition temperature (Tg) of about 53.0° C. to about 60.0° C.

12. 1. A method of preparing a toner, including emulsion aggregation core-shell toner particles, comprising: the core comprises a first styrene-acrylate copolymer, a second styrene-acrylate copolymer, a wax, and an optional colorant; the first styrene-acrylate copolymer is a styrene-n-butyl acrylate-β-carboxyethyl acrylate copolymer having a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0° C. to about 61.0° C.; the second styrene-acrylate copolymer is a styrene-n-butyl acrylate-β-carboxyethyl acrylate copolymer having a weight average molecular weight of about 52,000 g / mol to about 58,000 g / mol and an onset glass transition temperature of about 53.0° C. to about 57.0° C.; The method further comprising: obtaining a latex of said core styrene-acrylate copolymer, an aqueous dispersion of said optional colorant, and an aqueous dispersion of said wax; forming a mixture of the latex of the core styrene-acrylate copolymer, the aqueous dispersion of the optional colorant, and the aqueous dispersion of the wax; heating the mixture to a first temperature; maintaining said first temperature to form aggregate toner particles; adding a latex of a shell styrene-n-butyl acrylate-β-carboxyethyl acrylate copolymer to form a shell on the agglomerated particles; Optionally, adding a solution of a chelating agent; stopping further aggregation and increasing the temperature to a second temperature greater than the first temperature to coalesce the aggregated particles. followed by cooling and optionally washing and recovering the emulsion aggregation toner particles.

13. The method of claim 12, wherein the toner shell comprises a single styrene-n-butyl acrylate-β-carboxyethyl acrylate copolymer, the single shell styrene-acrylate copolymer being the first styrene-n-butyl acrylate-β-carboxyethyl acrylate copolymer having a weight average molecular weight of about 32,000 g / mol to about 38,000 g / mol and an onset glass transition temperature of about 57.0°C to about 61.0°C.

14. the wax is selected from the group consisting of Fischer-Tropsch waxes, polyethylene waxes, paraffin waxes, and combinations thereof; 13. The method of claim 12, wherein the optional colorant is present and is selected from cyan, magenta, yellow, black, carbon black, copper phthalocyanine, PR122, PR269, PY74, or combinations thereof.

15. The method of claim 12, comprising a batch emulsion aggregation process.

16. The method of claim 12, wherein the toner has an onset glass transition temperature (Tg) of from about 53.0° C. to about 60.0° C.

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