Preparation method of high-resolution carbon powder

Abstract

Through the matching of the composite pigment, the design of the core-shell structure, the coating of the conductive polymer, the coating of the non-crosslinked trifluoroethyl methacrylate polymer and the modification of the three-stage silicon dioxide, the contradiction among the charge stability, the erasing resistance, the weather resistance and the flowability of the carbon powder is synergistically solved, the atomization degree is reduced, and the resolution ratio of the carbon powder is improved.

Description

Technical Field

[0001] The invention relates to the technical field of carbon powder preparation, and in particular to a method for preparing high-resolution carbon powder. Background Art

[0002] Large-particle toner refers to toner with a particle size ranging from 15 to 30 μm. Large-particle toner can be used to create larger particle stacks, forming relief patterns on substrates for structural or aesthetic purposes. Compared to small-particle toner, large-particle toner is more likely to scatter during the printing process due to its larger particles, causing point explosions and reducing image quality. Furthermore, during the development process, a higher charge level is required to transfer this large-diameter toner.

[0003] When large-particle toner is applied to polyester-coated media, the compatibility between the ester bonds in the polyester coating and the toner resin directly affects the print's erasure resistance, making it prone to image detachment during abrasion testing. For example, styrene-acrylic resin systems, due to a lack of sufficient polar groups, exhibit weak chemical bonding with the polyester coating, resulting in erasure resistance generally below 95%, making them difficult to meet the demands of high-end printing applications.

[0004] The fluidity and anti-caking properties of toner directly affect the stability of printing and the storage life of toner. During storage, when the temperature and humidity rise, large-particle toner tends to partially melt, absorb moisture, and clump, affecting the fluidity of the toner, resulting in uneven developing density, and reduced printing uniformity and resolution. Existing technologies often use the method of adding anti-caking agents to reduce the degree of agglomeration. For example, the addition of zinc stearate can reduce surface energy, but it sacrifices charge stability. Therefore, under the premise of not affecting charge stability, improving the fluidity and anti-caking properties of toner through surface modification and material optimization is an important research direction in toner technology. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a method for preparing high-resolution carbon powder, comprising the following steps:

[0006] Step S1, preparing a wax dispersion: homogeneously mixing behenyl behenate, an aqueous solution of sodium dodecylbenzenesulfonate, and purified water to prepare a wax dispersion A;

[0007] Step S2, preparing a styrene acrylic resin-ester wax emulsion: wax dispersion A, purified water, ferrous sulfate aqueous solution, styrene, butyl acrylate, acrylic acid, trichlorobromomethane, hexanediol diacrylate, and sodium dodecylbenzenesulfonate aqueous solution are uniformly mixed, and an initiator solution is dropwise added to carry out a first-stage polymerization reaction; then, a ferrous sulfate solution is added to carry out a second-stage polymerization reaction to obtain a styrene acrylic resin-ester wax emulsion B;

[0008] Step S3, preparing a polyester dispersion: homogenously dispersing an amorphous polyester resin, methyl ethyl ketone, an ammonia solution, and purified water, and removing the methyl ethyl ketone by vacuum distillation to prepare a polyester dispersion C; mixing the polyester dispersion C with an aqueous solution of sodium dodecylbenzenesulfonate to obtain a polyester dispersion D;

[0009] Step S4, preparing a colorant dispersion: mixing carbon black pigment, phthalocyanine blue pigment, dioxazine violet pigment, sodium dodecylbenzenesulfonate aqueous solution, polysorbate 80, and purified water to prepare a colorant dispersion E;

[0010] Step S5, polyester coating of the styrene acrylic resin-ester wax core: Styrene acrylic resin-ester wax emulsion B, sodium dodecylbenzenesulfonate aqueous solution, ferrous sulfate solution, and colorant dispersion E are stirred and mixed to perform a first-stage reaction; then polyester dispersion D is added dropwise to perform a second-stage reaction to prepare a mixed solution F;

[0011] Step S6, melting the polyester surface layer: heating the mixed liquid G to melt the polyester surface layer; then cooling the mixed liquid G to form a mixed liquid H;

[0012] Step S7, washing and drying: filtering the mixed solution H, collecting the filter cake, washing, and drying it to produce carbon powder particles I;

[0013] Step S8, air flow crushing and classification: crushing the carbon powder particles I, and separating the particles through a turbine classifier to obtain carbon powder particles J;

[0014] Step S9: Surface modification of 3,4-ethylenedioxypyrrole: dispersing carbon powder particles J, toluenesulfonic acid, 3,4-ethylenedioxypyrrole, and ammonium persulfate in water to perform a polymerization reaction; collecting solid particles by filtration, washing, and spray drying to obtain carbon powder particles K;

[0015] Step S10, preparing an uncrosslinked trifluoroethyl methacrylate polymer: under a nitrogen atmosphere, stirring and mixing an aqueous solution of sodium dodecylbenzenesulfonate, purified water, and trifluoroethyl methacrylate to prepare an emulsion L; dropwise adding ammonium persulfate to the emulsion L to carry out a first-stage free radical polymerization reaction; then heating the emulsion to carry out a second-stage free radical polymerization reaction to obtain a latex M; and spray drying the latex M to obtain an uncrosslinked trifluoroethyl methacrylate polymer N;

[0016] Step S11, modification with an uncrosslinked trifluoroethyl methacrylate polymer: blending carbon powder particles K with an uncrosslinked trifluoroethyl methacrylate polymer N to obtain carbon powder particles O;

[0017] Step S12, adding L-type silicon dioxide: stirring and mixing carbon powder particles O and L-type silicon dioxide to obtain carbon powder particles P; the L-type silicon dioxide particle size is 80nm to 120nm;

[0018] Step S13, adding M-type silicon dioxide: stirring and mixing carbon powder particles P and M-type silicon dioxide to obtain carbon powder particles Q; the M-type silicon dioxide particle size is 30nm to 50nm;

[0019] Step S14, adding S-type silicon dioxide: stirring and mixing carbon powder particles Q and S-type silicon dioxide to obtain carbon powder; the particle size of the S-type silicon dioxide is 8nm to 16nm.

[0020] As a preferred technical solution, in step S1, the mass ratio of behenyl behenate, sodium dodecylbenzenesulfonate aqueous solution, and purified water is 30:(1.5-2):(2-2.2); the mass concentration of the sodium dodecylbenzenesulfonate aqueous solution is 18%-22%; the homogenization temperature is 85°C-95°C; and the D50 of the wax particles in the wax dispersion A is 240nm-250nm.

[0021] As a preferred technical solution, the initiator solution in step S2 includes hydrogen peroxide solution and ascorbic acid solution; in the first stage polymerization reaction, the mass ratio of wax dispersion A, purified water, ferrous sulfate aqueous solution, styrene, butyl acrylate, acrylic acid, trichlorobromomethane, hexanediol diacrylate, sodium dodecylbenzenesulfonate aqueous solution, hydrogen peroxide solution, and ascorbic acid solution is 30: (300-320): (0.01-0.02): (70-80): (30-40): (0.9-1.1): (0.9-1.1): (0.6-0.7): (0.9-1.1): (15-17): (3 0~32); the first stage polymerization reaction time is 5 hours to 6 hours; the first stage polymerization reaction temperature is 65℃~75℃; the mass ratio of wax dispersion A and ferrous sulfate aqueous solution in the second stage polymerization reaction is 30:(0.07~0.08); the second stage polymerization reaction time is 9 hours to 10 hours; the second stage polymerization reaction temperature is 85℃~95℃; the mass concentration of the ferrous sulfate aqueous solution is 0.4%~0.6%; the mass concentration of the sodium dodecylbenzenesulfonate aqueous solution is 18%~22%; the D50 of the particles in the styrene acrylic resin-ester wax emulsion is 250nm~260nm.

[0022] As a preferred technical solution, the mass ratio of the amorphous polyester resin, methyl ethyl ketone, ammonia solution, and purified water in step S3 is 25:(70-75):(22-26):(100-110); the homogenization speed is 8000 rpm-9000 rpm, and the homogenization time is 10 minutes-20 minutes; the reduced pressure distillation temperature is 80°C-85°C; the D50 of the polyester resin particles in the polyester dispersion C is 180 nm-200 nm; the acid value of the polyester resin in the polyester dispersion C is 10 mgKOH / g-12 mgKOH / g, and the glass transition temperature is 57°C; the mass ratio of the polyester dispersion C to the sodium dodecylbenzenesulfonate aqueous solution is 15:(0.25-0.35); the mass concentration of the sodium dodecylbenzenesulfonate aqueous solution is 18%-22%;

[0023] As a preferred technical solution, the mass ratio of the carbon black, phthalocyanine blue pigment, dioxazine violet pigment, sodium dodecylbenzenesulfonate aqueous solution, polysorbate 80, and purified water in step S4 is 20:(4-5):(1.8-2):(1.0-1.2):(9-11):(65-70); the mass concentration of the sodium dodecylbenzenesulfonate aqueous solution is 18%-22%; the homogenization method is wet bead milling homogenization; the wet bead milling homogenization rotor speed is 10m / s-12m / s, and the grinding beads are 0.1mm-0.2mm zirconium oxide beads; the homogenization temperature is 10°C-15°C; and the colorant particles D50 in the colorant dispersion E are 80nm-90nm.

[0024] As a preferred technical solution, the mass ratio of the styrene acrylic resin-ester wax emulsion B, sodium dodecylbenzenesulfonate aqueous solution, ferrous sulfate solution, and colorant dispersion E in step S5 is 85: (0.15-0.20): (0.5-0.6): (0.15-0.20): (4-5); the mass concentration of the ferrous sulfate aqueous solution is 5%-6%; the first stage reaction time is 60 minutes to 180 minutes; the first stage reaction temperature is 39°C to 41°C; the polyester dispersion D and the styrene acrylic resin-ester wax emulsion The mass ratio of B is 15:(75-90); the pH of the second-stage reaction is 7.9-8.1, and the reaction time of the second stage is 30 minutes to 40 minutes; the reaction temperature of the second stage is 43°C to 45°C; the mixed solution F, the sodium dodecylbenzenesulfonate aqueous solution, and purified water are mixed to prepare a mixed solution G; the mass ratio of the mixed solution F, the sodium dodecylbenzenesulfonate aqueous solution, and the purified water is 100:(5-6):(200-250); the mass concentration of the sodium dodecylbenzenesulfonate aqueous solution is 18% to 22%.

[0025] As a preferred technical solution, the melting temperature in step S6 is 65°C to 68°C; the melting time is 1 hour to 2 hours; and the temperature of the mixed solution H is 25°C to 35°C.

[0026] As a preferred technical solution, the drying temperature in step S7 is 40° C. to 45° C.; and the drying time is 40 hours to 50 hours.

[0027] As a preferred technical solution, the pulverization method in step S8 is air flow pulverization; the air flow pressure is 0.5MPa~1.0MPa; the air flow temperature is 25℃~40℃; the turbine speed is 10000rpm~15000rpm; and the D50 of the carbon powder particles J is 20μm~25μm.

[0028] As a preferred technical solution, in step S9, the mass ratio of the carbon powder particles J, toluenesulfonic acid, 3,4-ethylenedioxypyrrole, ammonium persulfate, and purified water is 10: (1-2): (0.8-1.2): (1.5-2): (90-110); the polymerization reaction pH is 1-1.5; the polymerization reaction time is 70 hours to 80 hours; the polymerization reaction temperature is 20°C to 30°C; the spray drying inlet temperature is 50°C to 55°C, the outlet temperature is 40°C to 45°C, the atomization pressure is 3 bar to 4 bar, and the feed rate is 5 mL / min to 7 mL / min;

[0029] As a preferred technical solution, the mass ratio of trifluoroethyl methacrylate, sodium dodecylbenzenesulfonate aqueous solution, and purified water in step S10 is 100: (0.015-0.02): (300-400); the mass concentration of the sodium dodecylbenzenesulfonate aqueous solution is 18%-22%; the emulsification temperature is 75°C-80°C; the mass ratio of the emulsion L to ammonium persulfate is (30-40): 1; the first stage free radical polymerization reaction time is 1 hour-2 hours; the second The stage free radical polymerization reaction temperature is 85°C to 90°C, and the reaction time is 2 hours to 3 hours; the final solid content of the latex M is 18% to 22%, and the average particle size is 90nm to 100nm; the particle size of the uncrosslinked trifluoroethyl methacrylate polymer N is 80nm to 150nm; the spray drying inlet temperature is 120°C to 125°C, the outlet temperature is 55°C to 65°C, the atomization pressure is 3bar to 4bar, and the feed rate is 5mL / min to 7mL / min.

[0030] As a preferred technical solution, the blending speed in step S11 is 1500 rpm, the blending time is 5 minutes, and the blending temperature is 45°C to 55°C; the mass ratio of the carbon powder particles K to the uncrosslinked trifluoroethyl methacrylate polymer N is 100:(1.3 to 1.5); and the surface coverage of the uncrosslinked trifluoroethyl methacrylate polymer-coated carbon powder particles K is 15% to 20%.

[0031] As a preferred technical solution, in step S12, the mass ratio of the carbon powder particles O and L-type silica is 100: (0.5-1.5); the stirring speed is 3000 rpm-3500 rpm; the mixing time is 15 minutes-20 minutes; the specific surface area of ​​the L-type silica is 40m 2 / g~60m 2 / g.

[0032] As a preferred technical solution, in step S13, the mass ratio of the carbon powder particles P and the M-type silica is 100:(1-2); the stirring speed is 3000rpm-3500rpm; the mixing time is 15 minutes-20 minutes; the specific surface area of ​​the M-type silica is 100m 2 / g~120m 2 / g.

[0033] As a preferred technical solution, in step S14, the mass ratio of the carbon powder particles Q and the S-type silica is 100:(0.2-0.5); the stirring speed is 3000 rpm-3500 rpm; and the mixing time is 15 minutes-20 minutes.

[0034] The glass transition temperature of uncrosslinked trifluoroethyl methacrylate latex is 67°C; the heat treatment temperature needs to be lower than the glass transition temperature to avoid excessive melting and particle adhesion, but needs to be close to the glass transition temperature to promote surface coating.

[0035] The chemical formula of behenyl behenate is C 21 H 43 COOC 22 H 45 . The melting point of behenyl behenate is higher than that of ordinary wax. This property allows it to maintain structural stability during carbon powder processing (such as the melting step), avoiding premature softening and resulting in particle adhesion. Its long-chain alkyl structure gives it extremely low surface energy, which can reduce the van der Waals force between carbon powder particles, thereby improving fluidity. Its hydrophobic properties work synergistically with uncross-linked trifluoroethyl methacrylate polymer (N) to enhance the moisture resistance of carbon powder and prevent moisture absorption and agglomeration in high humidity environments. Behenyl behenate has moderate compatibility with styrene acrylic resin and polyester. It can be evenly dispersed in the resin matrix and form a lubricated interface through microphase separation during the melting stage, reducing the risk of adhesion when the polyester surface is melted.

[0036] In step S3, p-toluenesulfonic acid is used as a dopant. Under the reaction system conditions, the sulfonate anions are embedded in the 3,4-ethylenedioxypyrrole backbone, forming an oxidized conductive structure. The surface potential of the doped carbon powder particles can be controlled by the type of oxidant: negative when ammonium persulfate is used, and positive when tri(p-toluenesulfonic acid) iron(III) is used. This results in a 20 nm thick conductive layer of poly(3,4-ethylenedioxypyrrole).

[0037] Through the above technical solutions, the present invention produces the following technical effects:

[0038] (1) By utilizing the polyester core-shell structure and controlling the polyester coating rate, the adhesion strength between the toner and the polyester-coated printing medium is improved, thereby enhancing the anti-erasure performance.

[0039] (2) Through the composite pigment ratio (carbon black + phthalocyanine blue + dioxazine violet), the spectral absorption range is expanded, and the C value and light resistance of carbon pink are improved.

[0040] (3) Modification with 3,4-ethylenedioxypyrrole conductive polymer improves the surface charge uniformity and conductive network continuity, improves the potential stability and particle size distribution, reduces the printing atomization value, and improves the resolution.

[0041] (4) By modifying the uncrosslinked trifluoroethyl methacrylate polymer, the surface hydrophobicity of the carbon powder is improved, the surface energy is reduced, the anti-caking performance is enhanced, and the resolution is improved.

[0042] (5) The fluidity, anti-caking properties and environmental humidity stability are improved through the synergistic modification of tertiary silica.

[0043] (6) By controlling the specific surface area of ​​carbon powder, the fluidity and anti-caking properties are improved. DETAILED DESCRIPTION

[0044] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the applicant provides an explanation and analysis through specific embodiments.

[0045] In this application, D50 represents the volume median particle size; the carbon black pigment is derived from Nipex 150; the phthalocyanine blue pigment is derived from Heliogen Blue 7086, index number CIPB 15:3; and the dioxazine violet pigment is derived from Hostaperm Violet P-RL, index number CIPV 23.

[0046] Polyester coated printing media is a high-performance polymer material with excellent mechanical strength, chemical stability and heat resistance. In printing media (such as laser printing paper, film, etc.), polyester coating is often used as a surface coating.

[0047] Example 1:

[0048] Step S1, preparing a wax dispersion: behenyl behenate, an aqueous solution of sodium dodecylbenzenesulfonate, and purified water are homogenously mixed to prepare wax dispersion A; the mass ratio of behenyl behenate, the aqueous solution of sodium dodecylbenzenesulfonate, and the purified water is 30:1.5:2; the mass concentration of the aqueous solution of sodium dodecylbenzenesulfonate is 18%; the homogenization temperature is 85° C.; the D50 of the wax particles in the wax dispersion A is 240 nm;

[0049] Step S2, preparing styrene acrylic resin-ester wax emulsion: wax dispersion A, purified water, ferrous sulfate aqueous solution, styrene, butyl acrylate, acrylic acid, trichlorobromomethane, hexanediol diacrylate, sodium dodecylbenzenesulfonate aqueous solution are mixed evenly, and an initiator solution is added dropwise to carry out a first-stage polymerization reaction; the initiator solution includes a hydrogen peroxide solution and an ascorbic acid solution; ferrous sulfate solution is added again to carry out a second-stage polymerization reaction to obtain styrene acrylic resin-ester wax emulsion B; in the first-stage polymerization reaction, wax dispersion A, purified water, ferrous sulfate aqueous solution, styrene, butyl acrylate, acrylic acid, trichlorobromomethane, hexanediol diacrylate, sodium dodecylbenzenesulfonate aqueous solution, The mass ratio of hydrogen peroxide solution to ascorbic acid solution is 30:300:0.01:70:30:0.9:0.9:0.6:0.9:15:30; the first-stage polymerization reaction time is 5 hours; the first-stage polymerization reaction temperature is 65° C.; in the second-stage polymerization reaction, the mass ratio of wax dispersion A to ferrous sulfate aqueous solution is 30:0.07; the second-stage polymerization reaction time is 9 hours; the second-stage polymerization reaction temperature is 85° C.; the mass concentration of the ferrous sulfate aqueous solution is 0.4%; the mass concentration of the sodium dodecylbenzenesulfonate aqueous solution is 18%; and the D50 of the particles in the styrene acrylic resin-ester wax emulsion is 250 nm.

[0050] Step S3, preparing a polyester dispersion: homogenizing and dispersing an amorphous polyester resin, methyl ethyl ketone, an ammonia solution, and purified water, and removing the methyl ethyl ketone by vacuum distillation to prepare a polyester dispersion C; the mass ratio of the amorphous polyester resin, methyl ethyl ketone, ammonia solution, and purified water is 25:70:22:100; the homogenization speed is 8000 rpm, and the homogenization time is 10 minutes; the vacuum distillation temperature is 80°C; the D50 of the polyester resin particles in the polyester dispersion C is 180 nm; the acid value of the polyester resin in the polyester dispersion C is 10 mgKOH / g, and the glass transition temperature is 57°C; the polyester dispersion C and an aqueous solution of sodium dodecylbenzenesulfonate are mixed to obtain a polyester dispersion D; the mass ratio of the polyester dispersion C to the aqueous solution of sodium dodecylbenzenesulfonate is 15:0.25; the mass concentration of the aqueous solution of sodium dodecylbenzenesulfonate is 18%;

[0051] Step S4, preparing a colorant dispersion: carbon black pigment, phthalocyanine blue pigment, dioxazine violet pigment, sodium dodecylbenzenesulfonate aqueous solution, polysorbate 80, and purified water are mixed and homogenized to prepare colorant dispersion E; the mass ratio of the carbon black, phthalocyanine blue pigment, dioxazine violet pigment, sodium dodecylbenzenesulfonate aqueous solution, polysorbate 80, and purified water is 20:4:1.8:1.0:9:65; the mass concentration of the sodium dodecylbenzenesulfonate aqueous solution is 18%; the homogenization method is wet bead milling; the wet bead milling rotor speed is 10 m / s, the grinding beads are 0.1 mm zirconium oxide beads; the homogenization temperature is 10° C.; the colorant particles D50 in colorant dispersion E are 80 nm;

[0052] Step S5, polyester coating styrene acrylic resin - ester wax core: Styrene acrylic resin - ester wax emulsion B, sodium dodecylbenzenesulfonate aqueous solution, ferrous sulfate solution, colorant dispersion E are stirred and mixed to carry out the first stage reaction; the mass ratio of the styrene acrylic resin - ester wax emulsion B, sodium dodecylbenzenesulfonate aqueous solution, ferrous sulfate solution, and colorant dispersion E is 85:0.15:0.5:0.15:4; the mass concentration of the ferrous sulfate aqueous solution is 5%; the first stage reaction time is 60 minutes; the first stage reaction temperature is 39°C; then the polyester is added dropwise The polyester dispersion D is subjected to a second-stage reaction to prepare a mixed solution F; the mass ratio of the polyester dispersion D to the styrene acrylic resin-ester wax emulsion B is 15:75; the pH of the second-stage reaction is 7.9, the second-stage reaction time is 30 minutes, and the second-stage reaction temperature is 43°C; the mixed solution F, an aqueous solution of sodium dodecylbenzenesulfonate, and purified water are mixed to prepare a mixed solution G; the mass ratio of the mixed solution F, the aqueous solution of sodium dodecylbenzenesulfonate, and purified water is 100:5:200; the mass concentration of the aqueous solution of sodium dodecylbenzenesulfonate is 18%;

[0053] Step S6, melting the polyester surface layer: heating the mixed liquid G to melt the polyester surface layer; then cooling the mixed liquid G to prepare a mixed liquid H; the melting temperature is 65°C; the melting time is 1 hour; the temperature of the mixed liquid H is 25°C;

[0054] Step S7, washing and drying: filtering the mixed solution H, collecting the filter cake, washing, and drying it to produce carbon powder particles I; the drying temperature is 40° C.; the drying time is 40 hours;

[0055] Step S8, air flow crushing and classification: crush the carbon powder particles I, and separate the particles through a turbine classifier after crushing to obtain carbon powder particles J; the crushing method is air flow crushing; the air flow pressure is 0.5 MPa; the air flow temperature is 25°C; the turbine speed is 10000 rpm; the D50 of the carbon powder particles J is 20 μm; the specific surface area of ​​the carbon powder particles J is 1.1 m 2 / g;

[0056] Step S9: Surface modification of 3,4-ethylenedioxypyrrole: Carbon powder particles J, toluenesulfonic acid, 3,4-ethylenedioxypyrrole, and ammonium persulfate are dispersed in water to carry out a polymerization reaction; the mass ratio of the carbon powder particles J, toluenesulfonic acid, 3,4-ethylenedioxypyrrole, ammonium persulfate, and purified water is 10:1:0.8:1.5:90; the polymerization reaction pH is 1; the polymerization reaction time is 70 hours; the polymerization reaction temperature is 20°C; the solid particles are collected by filtration, washed, and spray-dried to obtain carbon powder particles K; the spray drying air inlet temperature is 50°C, the air outlet temperature is 40°C, the atomization pressure is 3 bar, and the feed rate is 5 mL / min;

[0057] Step S10, preparing an uncrosslinked trifluoroethyl methacrylate polymer: under a nitrogen atmosphere, stirring and mixing an aqueous solution of sodium dodecylbenzenesulfonate, purified water, and trifluoroethyl methacrylate to prepare an emulsion L; the mass ratio of the trifluoroethyl methacrylate, the aqueous solution of sodium dodecylbenzenesulfonate, and the purified water is 100:0.015:300; the mass concentration of the aqueous solution of sodium dodecylbenzenesulfonate is 18%; the emulsification temperature is 75° C.; ammonium persulfate is dropwise added to the emulsion L to carry out a first-stage free radical polymerization reaction; the mass ratio of the emulsion to the ammonium persulfate is 30:1; The first stage free radical polymerization reaction time is 1 hour; the temperature is then raised to carry out the second stage free radical polymerization reaction to obtain latex M; the second stage free radical polymerization reaction temperature is 85° C., and the reaction time is 2 hours; the final solid content of the latex M is 18%, and the average particle size is 90 nm; the latex M is spray dried to obtain an uncrosslinked trifluoroethyl methacrylate polymer N; the particle size of the uncrosslinked trifluoroethyl methacrylate polymer N is 80 nm; the spray drying air inlet temperature is 120° C., the air outlet temperature is 55° C., the atomization pressure is 3 bar, and the feed rate is 5 mL / min;

[0058] Step S11, modification with an uncrosslinked trifluoroethyl methacrylate polymer: carbon powder particles K are blended with uncrosslinked trifluoroethyl methacrylate polymer N to obtain carbon powder particles O; the blending speed is 1500 rpm, the blending time is 5 minutes, and the blending temperature is 45° C.; the mass ratio of the carbon powder particles K to the uncrosslinked trifluoroethyl methacrylate polymer N is 100:1.3; and the surface coverage of the uncrosslinked trifluoroethyl methacrylate polymer-coated carbon powder particles K is 15%;

[0059] Step S12, adding L-type silica: stir and mix the carbon powder particles O and L-type silica to obtain carbon powder particles P; the mass ratio of carbon powder particles O and L-type silica is 100:0.5; the stirring speed is 3000 rpm; the mixing time is 15 minutes; the particle size of the L-type silica is 80 nm; the specific surface area of ​​the L-type silica is 40 m 2 / g;

[0060] Step S13, adding M-type silica: stir and mix the carbon powder particles P and M-type silica to obtain carbon powder particles Q; the mass ratio of carbon powder particles P and M-type silica is 100:1; the stirring speed is 3000 rpm; the mixing time is 15 minutes; the particle size of the M-type silica is 30 nm; the specific surface area of ​​the M-type silica is 100 m 2 / g;

[0061] Step S14, adding S-type silica: stirring and mixing the carbon powder particles Q and S-type silica to obtain a carbon powder product; the mass ratio of the carbon powder particles Q and S-type silica is 100:0.2; the stirring speed is 3000 rpm; the mixing time is 15 minutes; the particle size of the S-type silica is 8 nm.

[0062] Example 2

[0063] In step S5, the mass ratio of the polyester dispersion D to the styrene acrylic resin-ester wax emulsion B is 15:30; other parameters are consistent with those in Example 1.

[0064] Example 3

[0065] In step S5, the mass ratio of the polyester dispersion D to the styrene acrylic resin-ester wax emulsion B is 15:90; other parameters are consistent with those in Example 1.

[0066] Example 4

[0067] In step S5, the mass ratio of the polyester dispersion D to the styrene acrylic resin-ester wax emulsion B is 15:150; other parameters are consistent with those in Example 1.

[0068] Test Example 1

[0069] The coverage of the polyester-coated styrene acrylic resin-ester wax core was determined with reference to ISO 19749:2021 "Nanotechnologies—Measurements of particle size and shape distributions by scanning electron microscopy".

[0070] The anti-friction properties of carbon powder were determined with reference to GB / T 7706-2008.

[0071] The fluidity of carbon powder was determined with reference to GB / T 31057.3-2018 “Tests for physical properties of granular materials—Part 3: Determination of fluidity”.

[0072] The test results are shown in the table below.

[0073] Table 1: Test results of Examples 1-4

[0074]

[0075] In step S5, the process of polyester coating the styrene-acrylic resin-ester wax core is achieved through the synergistic effect of electrostatic adsorption and temperature-induced phase separation. First, ferrous sulfate acts as a cationic bridging agent to neutralize the negative charges on the surfaces of the styrene-acrylic resin-ester wax emulsion (B) and the polyester dispersion (D), reducing electrostatic repulsion and promoting the adsorption of polyester particles onto the core surface. The polyester chain segments are partially embedded in the styrene-acrylic resin surface through interfacial diffusion to form a transition layer. At the same time, hydrophobic interactions (the compatibility of polyester with styrene-acrylic resin and the van der Waals force of ester wax) further strengthen the coating structure. This coating method avoids the problem of uneven coating during traditional mechanical mixing and overcomes the excessive cross-linking defect of the in-situ polymerization method.

[0076] The polyester coverage directly affects the adhesion strength of toner to polyester-coated print media. When the coverage is 15% or higher, the ester bond structure of the polyester resin forms intermolecular forces with the polyester-coated print media, significantly improving erasure resistance. At lower coverage, the styrene-acrylic resin dominates the surface, resulting in poor compatibility with the polyester-coated print media and deteriorating erasure resistance.

[0077] Polyester coverage modulates fluidity by changing surface properties. Excessive coverage increases polyester viscosity, causing particles to stick together and reducing fluidity. This application selected a polyester coverage of 8% to 22% to improve the toner's anti-erasure properties while maintaining good fluidity, balancing surface chemical and physical rheological properties.

[0078] Example 5

[0079] In step S4 , only carbon black pigment is used, without adding phthalocyanine blue pigment or dioxazine violet pigment, and other parameters are consistent with those in Example 1.

[0080] Test Example 2

[0081] Colorimetry was determined with reference to ISO 11664-4:2019 “Colorimetry — Part 4: CIE 1976 Lab color space”.

[0082] The light fastness was evaluated by referring to ASTM D3424 “Standard Practice for Evaluating the Relative Lightfastness and Weathering Resistance of Printed Materials” (exposure to a light source with a wavelength of 280 nm for 216 hours).

[0083] The test results are shown in the table below. The chromaticity C value of Example 1 is significantly better than that of Example 5, and is closer to the ideal neutral black. Example 1 accurately compensates for the reflection deviation of carbon black in the blue-violet and red-yellow bands through the synergistic effect of phthalocyanine blue and dioxazine violet, significantly reduces the chromaticity C value, and presents a purer neutral black characteristic. The synergistic effect of phthalocyanine blue and dioxazine violet broadens the spectral absorption range, especially enhances the color rendering intensity in the blue-violet region, making the color gamut wider and the color saturation higher. However, Example 5 relies only on carbon black, and its chromaticity C value is higher, reflecting the inherent color deviation tendency of carbon black, which causes the printing effect to deviate from the strict neutral black standard. The composite pigment system of the present application can achieve high-fidelity neutral black printing.

[0084] The optical density decay rate in Example 1 is significantly lower than that in Example 5, demonstrating that the composite pigment system improves photostability. The rigid conjugated structure of phthalocyanine blue and the UV absorption properties of dioxazine violet effectively inhibit photooxidation and reduce carbon black degradation under light. In contrast, the single carbon black in Example 5, lacking the protective effect of the auxiliary pigment, exhibits more significant optical density decay, making printed products prone to fading over long-term use.

[0085] Table 2: Test results of Example 1 and Example 5

[0086] Sample name Chromaticity C value Optical density attenuation (%) Example 1 Finished Carbon Powder 0.2 8.6 Example 5 Finished Carbon Powder 0.9 19.1

[0087] Example 6

[0088] In step S8, the specific surface area of ​​the carbon powder particles J is controlled to be 0.5 m 2 / g; other parameters are consistent with those in Example 1.

[0089] Example 7

[0090] In step S8, the specific surface area of ​​the carbon powder particles J is controlled to be 1.5 m 2 / g; other parameters are consistent with those in Example 1.

[0091] Example 8

[0092] In step S8, the specific surface area of ​​the carbon powder particles J is controlled to be 2.0 m 2 / g; other parameters are consistent with those in Example 1.

[0093] Test Example 3

[0094] The specific surface area was determined by the gas adsorption BET method according to GB / T 19587-2017.

[0095] The fluidity of carbon powder was determined with reference to GB / T 31057.3-2018 “Tests for physical properties of granular materials—Part 3: Determination of fluidity”.

[0096] Refer to JB / T 8262.1-2013, "Dry toner for electrostatic copying - Part 1: Test method for caking temperature," to determine the anti-caking temperature of toner. The higher the anti-caking temperature, the stronger the anti-caking performance.

[0097] Toner print fogging evaluation method: Load toner into the developer tank. First, print 10 all-black A3 test sheets to consume the toner in the developer and trigger automatic toner replenishment. Then, print 20 A4 test sheets (with a 3cm black center band and the rest white). Use a Hunter luminance meter to measure the brightness change in the white area and calculate the fogging value (brightness before printing minus brightness after printing). The average of these 20 measurements is used as the final fogging value.

[0098] The test results are shown in the table below. The data in Table 3 show that the specific surface area of ​​carbon powder particles has a nonlinear relationship with performance. 2 / g increased to 1.1m 2 / g, the angle of repose decreases, the compressibility improves, and a moderate increase in the specific surface area can effectively block the direct contact between carbon powder particles and improve fluidity by enhancing the anchoring effect of the surface modifier (silicon dioxide); but when the specific surface area exceeds 1.5m 2 / g, the specific surface area of ​​the particles increases, the surface energy increases, the anti-caking performance decreases, and it is easy to cause particle agglomeration; the repose angle increases, the compressibility increases, and the fluidity decreases; at the same time, the atomization value jumps; excessive surface adsorption will aggravate the scattering of toner in the non-printing area, seriously affecting the printing accuracy.

[0099] Specific surface area is 1.0-1.5m 2 / g range, which can not only suppress particle scattering but also maintain fluidity, achieving dual optimization of fluidity and printing accuracy. By balancing the surface modification effect and thermal stability, the anti-caking temperature is maintained above 54°C, meeting the storage requirements in high temperature and high humidity environments.

[0100] Table 3: Test results of Example 1, Examples 6-8

[0101]

[0102] Example 9

[0103] The surface coating with 3,4-ethylenedioxypyrrole in step S9 was not performed; other parameters were the same as those in Example 1.

[0104] Test Example 4

[0105] Refer to ISO 13099-2 Zeta potential measurement method to measure the potential fluctuation of carbon powder.

[0106] The particle size distribution of carbon powder was determined with reference to GB / T 19077-2016 “Particle size distribution by laser diffraction method”.

[0107] The fluidity of carbon powder was determined with reference to GB / T 31057.3-2018 “Tests for physical properties of granular materials—Part 3: Determination of fluidity”.

[0108] Refer to JB / T 8262.1-2013, "Dry toner for electrostatic copying - Part 1: Test method for caking temperature," to determine the anti-caking temperature of toner. The higher the anti-caking temperature, the stronger the anti-caking performance.

[0109] The test results are shown in the table below.

[0110] 3,4-ethylenedioxypyrrole coating improves the surface charge uniformity of carbon powder. 3,4-ethylenedioxypyrrole monomers are oxidatively polymerized to form poly-3,4-ethylenedioxypyrrole. As a conductive polymer, poly-3,4-ethylenedioxypyrrole forms a continuous conductive network on the surface of carbon powder, which can effectively disperse and conduct charges, quickly balance local charge accumulation, and eliminate surface charge density differences. Compared with the uneven charge distribution caused by local contact in the traditional triboelectric charging process (such as the "charge patch effect"), the 3,4-ethylenedioxypyrrole coating layer achieves rapid charge migration and redistribution through its conjugated structure, thereby avoiding the formation of local high charge density areas, improving charge distribution uniformity, reducing the scattering phenomenon during the development process, and improving printing accuracy (such as reducing background gray and ghosting).

[0111] Table 4: Test results of charge uniformity of finished carbon powder

[0112] Sample name Potential fluctuation range Example 1 ±8mV Example 9 ±27mV

[0113] 3,4-ethylenedioxypyrrole modification inhibits carbon powder aggregation. 3,4-ethylenedioxypyrrole forms a poly(3,4-ethylenedioxypyrrole) conductive layer after oxidative polymerization, and the sulfonate anion (SO3 - ) are embedded in the main chain, imparting a uniform negative charge distribution to the carbon powder surface. This effectively inhibits physical contact between particles through electrostatic repulsion, reducing the tendency for van der Waals forces to drive agglomeration, thereby significantly inhibiting carbon powder aggregation and improving dispersibility. In contrast, the unmodified Example 9 exhibits uneven charge distribution, and localized charge patches easily induce selective agglomeration, resulting in an increase in D90 and a deterioration in Span value. Although D50 is 21 μm in both cases, the particle size distribution of Example 1 is narrower, surpassing that of Example 9.

[0114] Table 5: Particle size distribution test results of finished carbon powders in Example 1 and Example 9

[0115] Sample name Volume median particle size D50 Distribution span (Span) Volume particle size D90 Example 1 21μm 1.2 24μm Example 9 21μm 1.8 29μm

[0116] 3,4-ethylenedioxypyrrole modification improves the fluidity of carbon powder. The uniformly distributed negative charge of the 3,4-ethylenedioxypyrrole coating enhances the electrostatic repulsion between particles, keeping the carbon powder particles loose during flow and improving fluidity.

[0117] The modified poly(3,4-ethylenedioxypyrrole) conductive layer was doped with sulfonate (SO3 - ) gives the carbon powder surface a uniform negative charge, effectively inhibiting the physical contact between particles through electrostatic repulsion, reducing the agglomeration tendency driven by van der Waals forces at high temperatures, and thus improving the anti-caking performance.

[0118] Table 6: Test results of finished carbon powder of Example 1 and Example 9

[0119]

[0120] Example 10

[0121] In step S10, divinylbenzene as a crosslinking agent is added to prepare a crosslinked trifluoroethyl methacrylate polymer, wherein the mass ratio of trifluoroethyl methacrylate to divinylbenzene is 10:1; other parameters are consistent with those in Example 1.

[0122] Test Example 5

[0123] The contact angle of carbon powder measured using the sessile drop method is used to evaluate hydrophobicity. The larger the contact angle, the stronger the hydrophobicity.

[0124] Refer to JB / T 8262.1-2013, "Dry toner for electrostatic copying - Part 1: Test method for caking temperature," to determine the anti-caking temperature of toner. The higher the anti-caking temperature, the stronger the anti-caking performance.

[0125] The test results are shown in the table below. Compared with the cross-linked trifluoroethyl methacrylate polymer coating (Example 10), the uncross-linked trifluoroethyl methacrylate polymer coating (Example 1) more significantly improves the hydrophobicity and anti-caking performance of the carbon powder. At the blending temperature, the uncross-linked trifluoroethyl methacrylate polymer is a flexible linear molecular chain, which forms a continuous and uniform coating layer on the surface of the carbon powder through physical adsorption, covering more of the carbon powder surface, which can enhance the hydrophobicity and increase the contact angle; the cross-linked trifluoroethyl methacrylate polymer is mainly spherical during blending, and only partially contacts the surface of the carbon powder. The coating layer is relatively uneven and discontinuous, and the hydrophobicity is not as good as the uncross-linked trifluoroethyl methacrylate polymer coating.

[0126] The trifluoroethyl group in uncrosslinked trifluoroethyl methacrylate polymer has extremely low surface energy, effectively reducing the adhesion between carbon powder particles. However, due to the relatively uneven and discontinuous coating of the crosslinked trifluoroethyl methacrylate polymer, its anti-caking performance is inferior to that of the uncrosslinked trifluoroethyl methacrylate polymer coating. Furthermore, the uniform and continuous fluorinated polymer forms a hydrophobic layer on the carbon powder surface, which can reduce the effects of ambient humidity on the carbon powder (such as caking caused by high humidity in summer).

[0127] Table 7: Test results of hydrophobicity and anti-caking properties of finished carbon powders of Example 1 and Example 10

[0128] Sample name Contact angle (degrees) Anti-caking temperature (℃) Example 1 111 55.1 Example 10 96 52.3

[0129] Example 11

[0130] Step S12 was not performed, and L-type silica was not added; other parameters were consistent with those in Example 1.

[0131] Example 12

[0132] Step S13 was not performed, and M-type silica was not added; other parameters were consistent with those in Example 1.

[0133] Example 13

[0134] Step S14 was not performed and S-type silica was not added; other parameters were consistent with those in Example 1.

[0135] Test Example 6

[0136] Refer to JB / T 8262.1-2013, "Dry toner for electrostatic copying - Part 1: Test method for caking temperature," to determine the anti-caking temperature of toner. The higher the anti-caking temperature, the stronger the anti-caking performance.

[0137] The fluidity of carbon powder was determined with reference to GB / T 31057.3-2018 “Tests for physical properties of granular materials—Part 3: Determination of fluidity”.

[0138] The test results are shown in the table below. As can be seen from the data in Table 8, Example 11, which lacks L-type silica, exhibits a significantly increased angle of repose, degraded compressibility, and the greatest reduction in anti-caking temperature, demonstrating that L-type particles play a key role in enhancing anti-caking performance. L-type silica is a "large silica gel," and its large particle size forms a physical framework that effectively prevents close contact between carbon powder particles and reduces agglomeration caused by van der Waals forces. L-type silica has a moderate specific surface area, providing sufficient surface modification sites while preventing excessive surface energy from causing particle adhesion, thereby enhancing anti-caking performance.

[0139] In Example 12, the absence of M-type silica reduced the anti-caking temperature and increased the compressibility. M-type silica, with a size between L and S types, can fill the gaps between large particles, collaboratively building the skeleton structure and forming a more uniform particle stacking system; it also prevents particle adhesion caused by excessive surface energy, further enhancing anti-caking performance.

[0140] Nano-sized S-type silica can tightly fill the microscopic gaps of L / M-type particles to form a denser surface protection layer, lower the surface energy, and reduce the direct contact area between carbon powder particles, thereby further enhancing the anti-caking performance.

[0141] Table 8: Fluidity and anti-caking test results

[0142]

[0143] Example 14

[0144] Step S1, preparing a wax dispersion: behenyl behenate, an aqueous solution of sodium dodecylbenzenesulfonate, and purified water are homogenously mixed to prepare wax dispersion A; the mass ratio of behenyl behenate, the aqueous solution of sodium dodecylbenzenesulfonate, and the purified water is 30:1.7:2.1; the mass concentration of the aqueous solution of sodium dodecylbenzenesulfonate is 20%; the homogenization temperature is 90° C.; the D50 of the wax particles in the wax dispersion A is 245 nm;

[0145] Step S2, preparing styrene acrylic resin-ester wax emulsion: wax dispersion A, purified water, ferrous sulfate aqueous solution, styrene, butyl acrylate, acrylic acid, trichlorobromomethane, hexanediol diacrylate, and sodium dodecylbenzenesulfonate aqueous solution are uniformly mixed, and an initiator solution is added dropwise to carry out a first-stage polymerization reaction; the initiator solution includes a hydrogen peroxide solution and an ascorbic acid solution; the ferrous sulfate solution is added again to carry out a second-stage polymerization reaction to obtain styrene acrylic resin-ester wax emulsion B; in the first-stage polymerization reaction, the wax dispersion A, purified water, ferrous sulfate aqueous solution, styrene, butyl acrylate, acrylic acid, trichlorobromomethane, hexanediol diacrylate, sodium dodecylbenzenesulfonate aqueous solution, hydrogen peroxide solution and ascorbic acid solution are mixed. The mass ratio of the hydrogen solution and the ascorbic acid solution is 30:310:0.015:75:35:1.0:1.0:0.65:1.0:16:31; the first-stage polymerization reaction time is 5.5 hours; the first-stage polymerization reaction temperature is 70°C; in the second-stage polymerization reaction, the mass ratio of the wax dispersion A and the ferrous sulfate aqueous solution is 30:0.075; the second-stage polymerization reaction time is 9.5 hours; the second-stage polymerization reaction temperature is 90°C; the mass concentration of the ferrous sulfate aqueous solution is 0.5%; the mass concentration of the sodium dodecylbenzenesulfonate aqueous solution is 19%; and the D50 of the particles in the styrene acrylic resin-ester wax emulsion is 255 nm.

[0146] Step S3, preparing a polyester dispersion: homogenizing and dispersing an amorphous polyester resin, methyl ethyl ketone, an ammonia solution, and purified water, and removing the methyl ethyl ketone by vacuum distillation to prepare a polyester dispersion C; the mass ratio of the amorphous polyester resin, methyl ethyl ketone, ammonia solution, and purified water is 25:73:25:105; the homogenization speed is 8500 rpm, and the homogenization time is 15 minutes; the vacuum distillation temperature is 82° C.; the D50 of the polyester resin particles in the polyester dispersion C is 190 nm; the acid value of the polyester resin in the polyester dispersion C is 11 mgKOH / g, and the glass transition temperature is 57° C.; the polyester dispersion C and an aqueous solution of sodium dodecylbenzenesulfonate are mixed to obtain a polyester dispersion D; the mass ratio of the polyester dispersion C to the aqueous solution of sodium dodecylbenzenesulfonate is 15:0.3; and the mass concentration of the aqueous solution of sodium dodecylbenzenesulfonate is 19%;

[0147] Step S4, preparing a colorant dispersion: carbon black pigment, phthalocyanine blue pigment, dioxazine violet pigment, sodium dodecylbenzenesulfonate aqueous solution, polysorbate 80, and purified water are mixed and homogenized to prepare colorant dispersion E; the mass ratio of the carbon black, phthalocyanine blue pigment, dioxazine violet pigment, sodium dodecylbenzenesulfonate aqueous solution, polysorbate 80, and purified water is 20:4.5:1.9:1.1:10:68; the mass concentration of the sodium dodecylbenzenesulfonate aqueous solution is 19%; the homogenization method is wet bead milling; the wet bead milling rotor speed is 11 m / s, the grinding beads are 0.15 mm zirconium oxide beads; the homogenization temperature is 12°C; the colorant particles D50 in colorant dispersion E are 85 nm;

[0148] Step S5, polyester coating styrene acrylic resin - ester wax core: Styrene acrylic resin - ester wax emulsion B, sodium dodecylbenzenesulfonate aqueous solution, ferrous sulfate solution, and colorant dispersion E are stirred and mixed to perform a first-stage reaction; the mass ratio of the styrene acrylic resin - ester wax emulsion B, sodium dodecylbenzenesulfonate aqueous solution, ferrous sulfate solution, and colorant dispersion E is 85:0.18:0.55:0.17:4.5; the mass concentration of the ferrous sulfate aqueous solution is 5.5%; the first-stage reaction time is 120 minutes; the first-stage reaction temperature is 40°C; then dripping Add polyester dispersion D and conduct a second-stage reaction to prepare mixed solution F; the mass ratio of polyester dispersion D to styrene acrylic resin-ester wax emulsion B is 15:80; the pH of the second-stage reaction is 8.0, the second-stage reaction time is 35 minutes, and the second-stage reaction temperature is 44°C; the mixed solution F, sodium dodecylbenzenesulfonate aqueous solution, and purified water are mixed to prepare mixed solution G; the mass ratio of the mixed solution F, sodium dodecylbenzenesulfonate aqueous solution, and purified water is 100:5.5:220; the mass concentration of the sodium dodecylbenzenesulfonate aqueous solution is 19%;

[0149] Step S6, melting the polyester surface layer: heating the mixed liquid G to melt the polyester surface layer; then cooling the mixed liquid G to prepare a mixed liquid H; the melting temperature is 67°C; the melting time is 1.5 hours; the temperature of the mixed liquid H is 30°C;

[0150] Step S7, washing and drying: filtering the mixed solution H, collecting the filter cake, washing, and drying it to produce carbon powder particles I; the drying temperature is 42° C.; the drying time is 45 hours;

[0151] Step S8, air flow crushing and classification: crush the carbon powder particles I, and separate the particles through a turbine classifier after crushing to obtain carbon powder particles J; the crushing method is air flow crushing; the air flow pressure is 0.8 MPa; the air flow temperature is 30°C; the turbine speed is 12000 rpm; the D50 of the carbon powder particles J is 22 μm; the specific surface area of ​​the carbon powder particles J is 1.2 m 2 / g;

[0152] Step S9: Surface modification of 3,4-ethylenedioxypyrrole: dispersing carbon powder particles J, toluenesulfonic acid, 3,4-ethylenedioxypyrrole, and ammonium persulfate in water to carry out a coating polymerization reaction; the mass ratio of the carbon powder particles J, toluenesulfonic acid, 3,4-ethylenedioxypyrrole, ammonium persulfate, and purified water is 10:1.5:1.0:1.8:100; the polymerization reaction pH is 1.2; the polymerization reaction time is 75 hours; the polymerization reaction temperature is 25°C; the solid particles are collected by filtration, washed, and spray-dried to obtain carbon powder particles K; the spray drying air inlet temperature is 53°C, the air outlet temperature is 42°C, the atomization pressure is 3.5 bar, and the feed rate is 6 mL / min;

[0153] Step S10, preparing an uncrosslinked trifluoroethyl methacrylate polymer: under a nitrogen atmosphere, stirring and mixing an aqueous solution of sodium dodecylbenzenesulfonate, purified water, and trifluoroethyl methacrylate to prepare an emulsion L; the mass ratio of the trifluoroethyl methacrylate, the aqueous solution of sodium dodecylbenzenesulfonate, and the purified water is 100:0.017:350; the mass concentration of the aqueous solution of sodium dodecylbenzenesulfonate is 20%; the emulsification temperature is 79°C; ammonium persulfate is added dropwise to the emulsion L to carry out a first-stage free radical polymerization reaction; the mass ratio of the emulsion to the ammonium persulfate is 35:1; the first The first stage free radical polymerization reaction time is 1.5 hours; the temperature is then raised to carry out a second stage free radical polymerization reaction to obtain latex M; the second stage free radical polymerization reaction temperature is 88° C., and the reaction time is 2.5 hours; the final solid content of the latex M is 20%, and the average particle size is 95 nm; the latex M is spray-dried to obtain an uncrosslinked trifluoroethyl methacrylate polymer N; the particle size of the uncrosslinked trifluoroethyl methacrylate polymer N is 110 nm; the spray drying air inlet temperature is 122° C., the air outlet temperature is 60° C., the atomization pressure is 3.5 bar, and the feed rate is 6 mL / min;

[0154] Step S11, modification with an uncrosslinked trifluoroethyl methacrylate polymer: carbon powder particles K are blended with uncrosslinked trifluoroethyl methacrylate polymer N to obtain carbon powder particles O; the blending speed is 1500 rpm, the blending time is 5 minutes, and the blending temperature is 50° C.; the mass ratio of the carbon powder particles K to the uncrosslinked trifluoroethyl methacrylate polymer N is 100:1.3; and the surface coverage of the uncrosslinked trifluoroethyl methacrylate polymer-coated carbon powder particles K is 17%;

[0155] Step S12, adding L-type silica: stir and mix the carbon powder particles O and L-type silica to obtain carbon powder particles P; the mass ratio of carbon powder particles O to L-type silica is 100:1; the stirring speed is 3300 rpm; the mixing time is 18 minutes; the particle size of the L-type silica is 100 nm; the specific surface area of ​​the L-type silica is 50 m 2 / g;

[0156] Step S13, adding M-type silica: stirring and mixing carbon powder particles P and M-type silica to obtain carbon powder particles Q; the mass ratio of carbon powder particles P and M-type silica is 100:1.5; the stirring speed is 3300 rpm; the mixing time is 18 minutes; the particle size of the M-type silica is 40 nm; the specific surface area of ​​the M-type silica is 110 m 2 / g;

[0157] Step S14, adding S-type silica: stirring and mixing carbon powder particles Q and S-type silica to obtain carbon powder; the mass ratio of carbon powder particles Q and S-type silica is 100:0.4; the stirring speed is 3300 rpm; the mixing time is 18 minutes; the particle size of the S-type silica is 11 nm.

[0158] Example 15

[0159] Step S1, preparing a wax dispersion: behenyl behenate, an aqueous solution of sodium dodecylbenzenesulfonate, and purified water are homogenously mixed to prepare wax dispersion A; the mass ratio of behenyl behenate, the aqueous solution of sodium dodecylbenzenesulfonate, and the purified water is 30:2:2.2; the mass concentration of the aqueous solution of sodium dodecylbenzenesulfonate is 22%; the homogenization temperature is 95° C.; the D50 of the wax particles in the wax dispersion A is 250 nm;

[0160] Step S2, preparing styrene acrylic resin-ester wax emulsion: wax dispersion A, purified water, ferrous sulfate aqueous solution, styrene, butyl acrylate, acrylic acid, trichlorobromomethane, hexanediol diacrylate, sodium dodecylbenzenesulfonate aqueous solution are mixed evenly, and an initiator solution is added dropwise to carry out a first-stage polymerization reaction; the initiator solution includes a hydrogen peroxide solution and an ascorbic acid solution; ferrous sulfate solution is added again to carry out a second-stage polymerization reaction to obtain styrene acrylic resin-ester wax emulsion B; in the first-stage polymerization reaction, wax dispersion A, purified water, ferrous sulfate aqueous solution, styrene, butyl acrylate, acrylic acid, trichlorobromomethane, hexanediol diacrylate, sodium dodecylbenzenesulfonate aqueous solution, The mass ratio of hydrogen peroxide solution to ascorbic acid solution is 30:300:0.01:80:40:1.1:1.1:0.7:1.1:17:32; the first-stage polymerization reaction time is 6 hours; the first-stage polymerization reaction temperature is 75°C; the mass ratio of wax dispersion A to ferrous sulfate aqueous solution in the second-stage polymerization reaction is 30:0.08; the second-stage polymerization reaction time is 10 hours; the second-stage polymerization reaction temperature is 95°C; the mass concentration of the ferrous sulfate aqueous solution is 0.6%; the mass concentration of the sodium dodecylbenzenesulfonate aqueous solution is 22%; and the D50 of the particles in the styrene acrylic resin-ester wax emulsion is 260 nm.

[0161] Step S3, preparing a polyester dispersion: homogenizing and dispersing an amorphous polyester resin, methyl ethyl ketone, an ammonia solution, and purified water, and removing the methyl ethyl ketone by vacuum distillation to prepare a polyester dispersion C; the mass ratio of the amorphous polyester resin, methyl ethyl ketone, ammonia solution, and purified water is 25:75:26:110; the homogenization speed is 9000 rpm, and the homogenization time is 20 minutes; the vacuum distillation temperature is 85°C; the D50 of the polyester resin particles in the polyester dispersion C is 200 nm; the acid value of the polyester resin in the polyester dispersion C is 12 mgKOH / g, and the glass transition temperature is 57°C; the polyester dispersion C and an aqueous solution of sodium dodecylbenzenesulfonate are mixed to obtain a polyester dispersion D; the mass ratio of the polyester dispersion C to the aqueous solution of sodium dodecylbenzenesulfonate is 15:0.35; the mass concentration of the aqueous solution of sodium dodecylbenzenesulfonate is 22%;

[0162] Step S4, preparing a colorant dispersion: carbon black pigment, phthalocyanine blue pigment, dioxazine violet pigment, sodium dodecylbenzenesulfonate aqueous solution, polysorbate 80, and purified water are mixed and homogenized to prepare colorant dispersion E; the mass ratio of the carbon black, phthalocyanine blue pigment, dioxazine violet pigment, sodium dodecylbenzenesulfonate aqueous solution, polysorbate 80, and purified water is 20:5:2:1.2:11:70; the mass concentration of the sodium dodecylbenzenesulfonate aqueous solution is 22%; the homogenization method is wet bead milling; the wet bead milling rotor speed is 12 m / s, the grinding beads are 0.2 mm zirconium oxide beads; the homogenization temperature is 15°C; the colorant particles in colorant dispersion E have a D50 of 90 nm;

[0163] Step S5, polyester coating styrene acrylic resin - ester wax core: Styrene acrylic resin - ester wax emulsion B, sodium dodecylbenzenesulfonate aqueous solution, ferrous sulfate solution, and colorant dispersion E are stirred and mixed to perform a first-stage reaction; the mass ratio of the styrene acrylic resin - ester wax emulsion B, sodium dodecylbenzenesulfonate aqueous solution, ferrous sulfate solution, and colorant dispersion E is 85:0.2:0.6:0.2:5; the mass concentration of the ferrous sulfate aqueous solution is 6%; the first-stage reaction time is 180 minutes; the first-stage reaction temperature is 41°C; then the polyester is added dropwise Dispersion liquid D is subjected to a second-stage reaction to prepare a mixed liquid F; the mass ratio of the polyester dispersion liquid D to the styrene acrylic resin-ester wax emulsion B is 15:90; the pH of the second-stage reaction is 8.1, the second-stage reaction time is 40 minutes, and the second-stage reaction temperature is 45°C; the mixed liquid F, the sodium dodecylbenzenesulfonate aqueous solution, and purified water are mixed to prepare a mixed liquid G; the mass ratio of the mixed liquid F, the sodium dodecylbenzenesulfonate aqueous solution, and the purified water is 100:6:250; the mass concentration of the sodium dodecylbenzenesulfonate aqueous solution is 22%;

[0164] Step S6, melting the polyester surface layer: heating the mixed liquid G to melt the polyester surface layer; then cooling the mixed liquid G to prepare a mixed liquid H; the melting temperature is 68°C; the melting time is 2 hours; the temperature of the mixed liquid H is 35°C;

[0165] Step S7, washing and drying: filtering the mixed solution H, collecting the filter cake, washing, and drying it to produce carbon powder particles I; the drying temperature is 45° C.; the drying time is 50 hours;

[0166] Step S8, air flow crushing and classification: crush the carbon powder particles I, and separate the particles through a turbine classifier after crushing to obtain carbon powder particles J; the crushing method is air flow crushing; the air flow pressure is 1.0 MPa; the air flow temperature is 40°C; the turbine speed is 15000 rpm; the D50 of the carbon powder particles J is 25 μm; the specific surface area of ​​the carbon powder particles J is 1.3 m 2 / g;

[0167] Step S9: Surface modification of 3,4-ethylenedioxypyrrole: Carbon powder particles J, toluenesulfonic acid, 3,4-ethylenedioxypyrrole, and ammonium persulfate are dispersed in water and subjected to a polymerization reaction; the mass ratio of the carbon powder particles J, toluenesulfonic acid, 3,4-ethylenedioxypyrrole, ammonium persulfate, and purified water is 10:2:1.2:2:110; the polymerization reaction pH is 1.5; the polymerization reaction time is 80 hours; the polymerization reaction temperature is 30°C; the solid particles are collected by filtration, washed, and spray-dried to obtain carbon powder particles K; the spray drying air inlet temperature is 55°C, the air outlet temperature is 45°C, the atomization pressure is 4 bar, and the feed rate is 7 mL / min;

[0168] Step S10, preparing an uncrosslinked trifluoroethyl methacrylate polymer: under a nitrogen atmosphere, stirring and mixing an aqueous solution of sodium dodecylbenzenesulfonate, purified water, and trifluoroethyl methacrylate to prepare an emulsion L; the mass ratio of the trifluoroethyl methacrylate, the aqueous solution of sodium dodecylbenzenesulfonate, and the purified water is 100:0.02:400; the mass concentration of the aqueous solution of sodium dodecylbenzenesulfonate is 22%; the emulsification temperature is 80°C; ammonium persulfate is added dropwise to the emulsion L to carry out a first-stage free radical polymerization reaction; the mass ratio of the emulsion to the ammonium persulfate is 40:1; The first stage free radical polymerization reaction time is 2 hours; the temperature is then raised to carry out the second stage free radical polymerization reaction to obtain latex M; the second stage free radical polymerization reaction temperature is 90°C, and the reaction time is 3 hours; the final solid content of the latex M is 22%, and the average particle size is 100 nm; the latex M is spray dried to obtain an uncrosslinked trifluoroethyl methacrylate polymer N; the particle size of the uncrosslinked trifluoroethyl methacrylate polymer N is 150 nm; the spray drying inlet air temperature is 125°C, the outlet air temperature is 65°C, the atomization pressure is 34 bar, and the feed rate is 7 mL / min;

[0169] Step S11, modification with an uncrosslinked trifluoroethyl methacrylate polymer: carbon powder particles K are blended with uncrosslinked trifluoroethyl methacrylate polymer N to obtain carbon powder particles O; the blending speed is 1500 rpm, the blending time is 5 minutes, and the blending temperature is 55° C.; the mass ratio of the carbon powder particles K to the uncrosslinked trifluoroethyl methacrylate polymer N is 100:1.5; and the surface coverage of the uncrosslinked trifluoroethyl methacrylate polymer-coated carbon powder particles K is 20%;

[0170] Step S12, adding L-type silica: stir and mix the carbon powder particles O and L-type silica to obtain carbon powder particles P; the mass ratio of carbon powder particles O and L-type silica is 100:1.5; the stirring speed is 3500 rpm; the mixing time is 20 minutes; the particle size of the L-type silica is 120 nm; the specific surface area of ​​the L-type silica is 60 m 2 / g;

[0171] Step S13, adding M-type silica: stirring and mixing carbon powder particles P and M-type silica to obtain carbon powder particles Q; the mass ratio of carbon powder particles P and M-type silica is 100:2; the stirring speed is 3500 rpm; the mixing time is 20 minutes; the particle size of the M-type silica is 50 nm; the specific surface area of ​​the M-type silica is 120 m 2 / g;

[0172] Step S14, adding S-type silica: stirring and mixing carbon powder particles Q and S-type silica to obtain carbon powder; the mass ratio of carbon powder particles Q and S-type silica is 100:0.5; the stirring speed is 3500 rpm; the mixing time is 20 minutes; the particle size of the S-type silica is 16 nm.

[0173] The test results of the finished carbon powder of Example 1, Example 14 and Example 15 are shown in the table below.

[0174] Table 9: Test results of finished carbon powders of Example 1, Example 14, and Example 15

[0175]

[0176] The present invention synergistically solves the contradictions among carbon powder charge stability, erasure resistance, weather resistance and fluidity through composite pigment ratio, core-shell structure design, conductive polymer coating, uncrosslinked trifluoroethyl methacrylate polymer coating and tertiary silica modification, thereby reducing atomization and improving toner resolution.

[0177] The preparation method of amorphous polyester resin A in this application is as follows: 39 parts by mole of isophthalic acid and 27 parts by mole of trimellitic anhydride as the polyvalent carboxylic acid component, 100 parts by mole of bisphenol A-2.3 parts of propylene oxide adduct and 37 parts by mole of ethylene glycol as the polyol component, and 1500 ppm of antimony trioxide as the polymerization catalyst are added to a reactor. The esterification reaction is carried out by heating to 265°C with a stirring rate of 120 rpm until the system stops producing water. The temperature is then lowered to 240°C and the system is vacuumed to 133 Pa over 40 minutes for a polycondensation reaction. The reaction endpoint is controlled by monitoring the stirring torque. The reaction is stopped when the resin reaches the softening temperature of 110°C, and the resin is discharged by nitrogen flushing. The final product is amorphous, with a glass transition temperature of approximately 57°C, an acid value of approximately 12 mgKOH / g, and a mass average molecular weight of approximately 26,000. The storage modulus (G') of this resin at 70°C is as high as 31,750,000 Pa, but drops sharply to 5,300 Pa at 100°C, indicating that it has both high-temperature fluidity and low-temperature rigidity.

Claims

1. A method for preparing high-resolution carbon powder, characterized in that: The following steps are involved: Step S1, preparing a wax dispersion: homogeneously mixing behenyl behenate, an aqueous solution of sodium dodecylbenzenesulfonate, and purified water to prepare a wax dispersion A; Step S2, preparing a styrene acrylic resin-ester wax emulsion: wax dispersion A, purified water, ferrous sulfate aqueous solution, styrene, butyl acrylate, acrylic acid, trichlorobromomethane, hexanediol diacrylate, and sodium dodecylbenzenesulfonate aqueous solution are uniformly mixed, and an initiator solution is dropwise added to carry out a first-stage polymerization reaction; then, a ferrous sulfate solution is added to carry out a second-stage polymerization reaction to obtain a styrene acrylic resin-ester wax emulsion B; Step S3, preparing a polyester dispersion: homogenously dispersing an amorphous polyester resin, methyl ethyl ketone, an aqueous ammonia solution, and purified water, and removing the methyl ethyl ketone by vacuum distillation to prepare a polyester dispersion C; then mixing the polyester dispersion C with an aqueous solution of sodium dodecylbenzenesulfonate to obtain a polyester dispersion D; Step S4, preparing a colorant dispersion: mixing carbon black pigment, phthalocyanine blue pigment, dioxazine violet pigment, sodium dodecylbenzenesulfonate aqueous solution, polysorbate 80, and purified water to prepare a colorant dispersion E; Step S5, polyester coating of the styrene acrylic resin-ester wax core: Styrene acrylic resin-ester wax emulsion B, sodium dodecylbenzenesulfonate aqueous solution, ferrous sulfate solution, and colorant dispersion E are stirred and mixed to perform a first-stage reaction; then polyester dispersion D is added dropwise to perform a second-stage reaction to prepare a mixed solution F; Step S6, melting the polyester surface layer: heating the mixed liquid G to melt the polyester surface layer; Then, the mixed solution G is cooled to prepare the mixed solution H; Step S7, washing and drying: filtering the mixed solution H, collecting the filter cake, washing, and drying it to produce carbon powder particles I; Step S8, air flow crushing and classification: crushing the carbon powder particles I, and separating the particles through a turbine classifier to obtain carbon powder particles J; Step S9: Surface modification of 3,4-ethylenedioxypyrrole: dispersing carbon powder particles J, toluenesulfonic acid, 3,4-ethylenedioxypyrrole, and ammonium persulfate in water to perform a polymerization reaction; collecting solid particles by filtration, washing, and spray drying to obtain carbon powder particles K; Step S10, preparing an uncrosslinked trifluoroethyl methacrylate polymer: under a nitrogen atmosphere, stirring and mixing an aqueous solution of sodium dodecylbenzenesulfonate, purified water, and trifluoroethyl methacrylate to prepare an emulsion L; dropwise adding ammonium persulfate to the emulsion L to carry out a first-stage free radical polymerization reaction; then raising the temperature to carry out a second-stage free radical polymerization reaction to obtain a latex M; The latex M is spray-dried to obtain an uncrosslinked trifluoroethyl methacrylate polymer N; Step S11, modification with an uncrosslinked trifluoroethyl methacrylate polymer: blending carbon powder particles K with an uncrosslinked trifluoroethyl methacrylate polymer N to obtain carbon powder particles O; Step S12, adding L-type silicon dioxide: stirring and mixing carbon powder particles O and L-type silicon dioxide to obtain carbon powder particles P; the L-type silicon dioxide particle size is 80nm to 120nm; Step S13, adding M-type silicon dioxide: stirring and mixing carbon powder particles P and M-type silicon dioxide to obtain carbon powder particles Q; the M-type silicon dioxide particle size is 30nm to 50nm; Step S14, adding S-type silicon dioxide: stirring and mixing carbon powder particles Q and S-type silicon dioxide to obtain carbon powder; the particle size of the S-type silicon dioxide is 8nm to 16nm.

2. The preparation method according to claim 1, characterized in that In step S2, the first stage polymerization reaction time is 5 hours to 6 hours; the first stage polymerization reaction temperature is 65°C to 75°C; the second stage polymerization reaction time is 9 hours to 10 hours; and the second stage polymerization reaction temperature is 85°C to 95°C.

3. The preparation method according to claim 2, characterized in that The melting temperature in step S6 is 65° C. to 68° C.; the melting time is 1 hour to 2 hours; and the temperature of the mixed solution H is 25° C. to 35° C.

4. The preparation method according to claim 3, characterized in that The mass ratio of the polyester dispersion D to the styrene acrylic resin-ester wax emulsion B in step S5 is 15:(75-90).

5. The preparation method according to claim 4, characterized in that In step S8 , the air flow pressure is 0.5 MPa to 1.0 MPa; the air flow temperature is 25° C. to 40° C.; the turbine speed is 10,000 rpm to 15,000 rpm; and the D50 of the carbon powder particles J is 20 μm to 25 μm.

6. The preparation method according to claim 5, characterized in that In step S12, the mass ratio of the carbon powder particles O and L-type silica is 100: (0.5-1.5); the stirring speed is 3000 rpm-3500 rpm; the mixing time is 15 minutes-20 minutes; the specific surface area of ​​the L-type silica is 40m 2 / g~60m 2 / g.

7. The preparation method according to claim 6, characterized in that The mass ratio of the carbon black, phthalocyanine blue pigment, dioxazine violet pigment, sodium dodecylbenzenesulfonate aqueous solution, polysorbate 80, and purified water in step S4 is 20:(4-5):(1.8-2):(1.0-1.2):(9-11):(65-70).

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