A charge regulator, its preparation method and application

Abstract

This invention discloses a charge regulator, its preparation method, and its application. The charge regulator comprises a phthalic acid compound with the structure shown in Formula I. The charge regulator of this invention (i.e., the phthalic acid compound with the structure shown in Formula I) exhibits excellent durability and stable charge under different temperatures and humidity levels. The charge regulator is used in the preparation of toner. By adjusting the pH of the solution, particles are induced to approach each other and gradually aggregate into clusters. Heating further causes the clusters to grow, and when they reach the desired size, their further growth is restricted. Heating above the resin's Tg temperature promotes the bonding of loose clusters into dense agglomerates. The aggregates are collected, dried, and other necessary components are added to obtain the toner. The toner of this invention has a fast charging rate and high charge, and its performance indicators meet the requirements for monochrome / color laser printing.

Description

Technical Field

[0001] This invention belongs to the field of toner preparation technology; specifically, it relates to a charge regulator, its preparation method, and its application. Background Technology

[0002] Toner, also known as carbon powder, toner, or electrostatic developer, is a powdered solid used in electrostatic imaging. It forms a developer with a carrier, participates in the developing process, and is ultimately fixed onto paper to form text or images. Toner is mainly composed of resin, toner, charge control agent, and auxiliary additives. Charge control agents (CCAs) are substances that regulate the charge on the toner during electrostatic copying and printing. During printing or copying, an electrostatic latent image is first formed on a photosensitive material, then developed by a toner, and finally transferred to a carrier such as paper for fixing to obtain a visible image. The photosensitive material is the core component of the developing equipment, and is classified into two types based on its structure: positively charged and negatively charged. For toner to develop on the electrostatic latent image formed by the photosensitive material, it needs to carry a charge of the opposite polarity to that of the latent image. The charge control agent plays a crucial role in changing the triboelectric characteristics of the toner, determining the rate of electrification during friction, concentrating the charge distribution of the toner, and enabling the toner to complete copying and printing.

[0003] Traditional negative charge regulators include azo metal complexes and tert-butyl salicylic acid metal complexes. However, these compounds are not evenly dispersed in resins and are prone to decomposition at high temperatures. As a result, when the charge regulator is added to the toner, it does not have a fast charging rate in actual printing, which affects the printing effect. Summary of the Invention

[0004] This invention discloses a phthalic acid compound, which has the advantages of simple synthesis, stability, solubility and good resin compatibility.

[0005] The technical solution of the present invention is as follows:

[0006] A phthalic acid compound with the structure shown in Formula I:

[0007]

[0008] Where R represents unsubstituted or substituted by one, two or more Cs. 1-20 Alkyl-substituted phenyl, where M is a zinc, chromium, aluminum, or calcium ion; X is an integer from 1 to 3; Y is an integer from 1 to 3;

[0009] Represents a benzene ring;

[0010] The two Rs are located in the ortho, para, or meta position of the benzene ring; preferably in the meta position.

[0011] According to an embodiment of the invention, the R is preferably unsubstituted or substituted by one, two or more Cs. 1-6 Alkyl-substituted phenyl, more preferably phenyl.

[0012] According to an embodiment of the present invention, M is preferably a zinc ion or an aluminum ion.

[0013] According to an exemplary embodiment of the present invention, the phthalic acid compound is CCA-Al or CCA-Zn as shown below;

[0014]

[0015] The present invention also provides a method for preparing phthalic acid compounds with the structure shown in Formula I above, comprising the following steps:

[0016] By mixing compound A, compound M, and an alkaline solution, phthalic acid compounds with the structure shown in Formula I are prepared.

[0017]

[0018] R has the meanings described above.

[0019] According to an embodiment of the present invention, the compound of formula A is, for example, 3,5-diphenylphthalic acid.

[0020] According to an embodiment of the present invention, the M-containing compound may be at least one of zinc chloride, aluminum nitrate, calcium chloride, and chromium chloride.

[0021] According to an embodiment of the present invention, the alkaline solution is an aqueous solution of an alkaline compound, which may be sodium hydroxide or potassium hydroxide; the mass concentration of the alkaline compound in the alkaline solution is 1-5 wt%, exemplarily 2 wt%.

[0022] According to an embodiment of the present invention, the molar ratio of the compound containing M, the compound of formula A, and the basic compound is 1:(1-4):(1-10), preferably 1:(1-3):(2-6), and exemplarily 1:1.8:4.

[0023] According to an embodiment of the present invention, the reaction time of each raw material is 24-60 hours, and exemplarily 48 hours.

[0024] According to an embodiment of the present invention, the preparation method further includes adjusting the prepared product to be acidic, for example, pH 3, by using 5% dilute hydrochloric acid.

[0025] According to an embodiment of the present invention, the preparation method further includes: dispersing the phthalic acid compound with the structure shown in Formula I in deionized water containing a dispersant to obtain a phthalic acid compound dispersion with the structure shown in Formula I.

[0026] According to an embodiment of the present invention, the dispersant is selected from at least one of sodium polyacrylate, polyacrylate-butyl acrylate copolymer, S-27000, and sodium dodecylbenzenesulfonate.

[0027] According to an embodiment of the present invention, the phthalic acid compound dispersion is stable under alkaline conditions, preferably the phthalic acid compound dispersion is an emulsion, and can be demulsified and precipitated under acidic conditions or with the addition of calcium chloride, etc.

[0028] The present invention also provides the application of phthalic acid compounds with the structure shown in Formula I as negative charge modifiers (CCA).

[0029] For example, the phthalic acid compound with the structure shown in Formula I is used as a negative charge control agent (CCA) in the preparation of developer toner for laser printing or electrostatic copying.

[0030] The present invention also provides a toner, wherein the raw materials for preparing the toner include phthalic acid compounds with the structure shown in Formula I; preferably, the raw materials include phthalic acid compounds with the structure shown in Formula I, wax, resin and pigment.

[0031] According to an embodiment of the present invention, in the toner, the phthalic acid compound with the structure shown in Formula I can be a dispersion of the phthalic acid compound with the structure shown in Formula I.

[0032] According to an embodiment of the present invention, the wax includes natural waxes (paraffin wax, carnauba wax, refined wax, etc.) and synthetic waxes (polyethylene wax, polypropylene wax, etc.).

[0033] According to an embodiment of the present invention, the resin may be a styrene-propylene copolymer resin, a polyester, or a polycarbonate.

[0034] According to an embodiment of the present invention, the pigment may be carbon black, pigment yellow, pigment cyan, etc.

[0035] According to an embodiment of the present invention, the mass ratio of the phthalic acid compound, wax, resin and pigment of the structure shown in Formula I is (1-10):(1-20):(60-100):(5-30), preferably (1-5):(5-10):(60-90):(10-20).

[0036] The present invention also provides a method for preparing the above-mentioned toner, the method comprising:

[0037] (1) Mix the phthalic acid compound, wax, resin and pigment with the structure shown in Formula I, adjust the mixed solution to acidity, and heat;

[0038] (2) Adjust the mixed solution in step (1) to alkalinity, heat it, and prepare toner.

[0039] According to an embodiment of the present invention, in step (1), the phthalic acid compound, wax, resin and pigment with the structure shown in Formula I are all introduced in the form of a dispersion.

[0040] Preferably, step (1) includes mixing an aqueous dispersion of phthalic acid compounds with the structure shown in Formula I, a wax emulsion, a resin emulsion, and an aqueous dispersion of pigments, adjusting the mixed solution to acidity, and heating.

[0041] According to an embodiment of the present invention, in step (1), the pH of the mixed solution is 2-4.

[0042] According to an embodiment of the present invention, in step (1), the heating temperature is 40-60°C, preferably 50-60°C; the heating time is 0.5-5h, preferably 1-3h.

[0043] According to an embodiment of the present invention, in step (2), the pH of the mixed solution is 8-10.

[0044] According to an embodiment of the present invention, in step (2), the heating temperature is 80-110℃, preferably 90-100℃; the heating time is 1-6h, preferably 3-5h.

[0045] According to an embodiment of the present invention, the method for preparing the toner further includes a post-processing step (3), in which the product in step (2) is filtered, washed, and dried to prepare the toner.

[0046] The beneficial effects of this invention are:

[0047] The charge regulator of this invention (i.e., a phthalic acid compound with the structure shown in Formula I) exhibits excellent durability and stable charge under different temperatures and humidity levels. When this charge regulator is used in toner preparation, the pH of the solution is adjusted to induce particles to approach each other and gradually aggregate into clusters. Heating further causes the clusters to grow, and once they reach the desired size, their further growth is restricted. Heating above the resin's Tg temperature promotes the bonding of loose clusters into dense aggregates. The aggregates are then collected, dried, and other necessary components are added to obtain the toner. The toner of this invention has a fast charging rate and high charge, and its performance indicators meet the requirements for monochrome / color laser printing.

[0048] Terminology Definitions and Explanations

[0049] Unless otherwise stated, the terms and descriptions in the context of this invention have the meanings described below.

[0050] "More than" means three or more.

[0051] Term "C" 1-20 "Alkyl" should be understood as referring to a straight-chain or branched saturated monovalent hydrocarbon group having 1 to 20 carbon atoms. For example, "C 1-10 "Alkyl" refers to straight-chain and branched alkyl groups having 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms. 1-6 "Alkyl" means a straight-chain or branched alkyl group having 1, 2, 3, 4, 5, or 6 carbon atoms. The alkyl group is, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, 2-methylbutyl, 1-methylbutyl, 1-ethylpropyl, 1,2-dimethylpropyl, neopentyl, 1,1-dimethylpropyl, 4-methylpentyl, 3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 2-ethylbutyl, 1-ethylbutyl, 3,3-dimethylbutyl, 2,2-dimethylbutyl, 1,1-dimethylbutyl, 2,3-dimethylbutyl, 1,3-dimethylbutyl, or 1,2-dimethylbutyl, or their isomers. Attached Figure Description

[0052] Figure 1 This is the synthetic route for 3,5-diphenylphthalic acid. Detailed Implementation

[0053] According to an embodiment of the present invention, the preparation method of the precursor of compound I (e.g., 3,5-diphenylphthalic acid) includes the following steps:

[0054] (S1) Ni(PPh3)2Cl2, dppm, zinc powder, zinc iodide, dimethyl butyryne diacetate, phenylacetylene and organic solvent are mixed and heated to prepare dimethyl 3,5-diphenylphthalate.

[0055] (S2) 3,5-Diphenylphthalic acid was prepared by reacting dimethyl 3,5-diphenylphthalate under alkaline conditions.

[0056] According to an embodiment of the present invention, the molar ratio of Ni(PPh3)2Cl2, dppm, zinc powder, zinc iodide, dimethyl butynedioate, and phenylacetylene is 1:1:(1-2):(1-2):(8-20):(20-40), and an exemplary ratio is 1:1:2:2:10:30.

[0057] According to an embodiment of the present invention, the organic solvent is acetonitrile, by example.

[0058] According to an embodiment of the present invention, in step (S1), the heating temperature is 60-90°C, exemplarily 80°C; the heating reaction time is 5-8 hours, exemplarily 6 hours.

[0059] According to an embodiment of the present invention, in step (S2), the alkaline condition is, for example, a methanol solution of sodium hydroxide; exemplarily, the concentration of sodium hydroxide is 2M.

[0060] According to an embodiment of the present invention, in step (S2), the reaction time is 12-48 hours, exemplarily 24 hours.

[0061] According to an embodiment of the present invention, in step (S2), after the reaction is completed, the pH is adjusted to 1-2 using an acid; for example, dilute hydrochloric acid is used for adjustment.

[0062] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0063] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0064] Preparation Example 1

[0065] The synthetic route for 3,5-diphenylphthalic acid is as follows: Figure 1 As shown.

[0066] Synthesis of dimethyl 3,5-diphenylphthalate: 6.6 g (10 mmol) Ni(PPh3)2Cl2, 3.9 g (10 mmol) dppm, 1.3 g (20 mmol) zinc powder, and 6.4 g (20 mmol) zinc iodide were added sequentially to a 250 mL three-necked flask. The mixture was first evacuated and then purged with nitrogen, and this process was repeated three times. 14.2 g (100 mmol) dimethyl butynedioate and 30.6 g (300 mmol) phenylacetylene were dissolved in 120 mL acetonitrile and added to the three-necked flask under nitrogen protection. The reaction was carried out at 80 °C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the organic solvent was removed under reduced pressure. The mixture was then separated and purified by column chromatography to obtain 24.3 g of the target product, dimethyl 3,5-diphenylphthalate (70% yield). 1H NMR (400MHz, CDCl3): δ8.23(d,J=1.2Hz,1H),7.77(d,J=1.2Hz,1H),7.64(d,J=7.4Hz,2H),7.49–7.39(m,8H),3.94(s,3H),3.69(s,3H); 13 C NMR (100MHz, CDCl3): δ169.20,166.22,142.24,141.24,139.33,139.12,133.40,132.67,129.02, 128.87,128.64,128.34,128.30,127.98,127.49,127.24,52.65,52.31; MS(EI,m / z,rel.%):346(M + ,46%),315(M) + -31,89%).

[0067] Synthesis of 3,5-diphenylphthalic acid: Dimethyl 3,5-diphenylphthalate (18.7 g, 54 mmol) was dissolved in 250 mL of 2M sodium hydroxide methanol solution and refluxed for 24 hours. The solution was cooled, methanol was removed under reduced pressure, and the pH was adjusted to 1-2 with dilute hydrochloric acid. The precipitate was filtered, washed, and dried to obtain 3,5-diphenylphthalic acid (i.e., CCA precursor) (15.5 g, 90%), melting point: 196-197 °C.

[0068] Preparation Example 2

[0069] Preparation of CCA-Zn: Zinc chloride (3.4 g, 25 mmol), 3,5-diphenylphthalic acid (14.3 g, 45 mmol) from Preparation Example 1, and 200 mL of an aqueous solution of 2 wt% sodium hydroxide were refluxed for 48 hours, cooled to room temperature, and adjusted to pH 3 with 5% dilute hydrochloric acid. The precipitate was filtered, washed, and dried to obtain CCA-Zn, i.e., phthalic acid compounds with the structure shown in Formula I, where X and Y are both 2.

[0070] Preparation Example 3

[0071] Preparation of CCA-Al: Aqueous solutions of aluminum nitrate (4.3 g, 20 mmol), 3,5-diphenylphthalic acid (14.3 g, 45 mmol) from Preparation Example 1, and 200 mL of 2 wt% sodium hydroxide were refluxed for 48 hours, cooled to room temperature, and adjusted to pH 3 with 5% dilute hydrochloric acid. The precipitate was filtered, washed, and dried to obtain CCA-Al, a phthalic acid compound with the structure shown in Formula I, where X and Y are 2 and 1, respectively.

[0072] Preparation Example 4

[0073] Preparation of CCA-Zn dispersion: In a 500 mL ball mill jar containing zirconium beads, add 20 g of CCA-Zn from Example 2, 175 mL of deionized water containing 2 g of sodium polyacrylate and 3 g of S-27000, and stir (500 rpm) for 0.5 hours to mix evenly; ball mill at 5000 rpm for 3 hours to obtain a stable CCA-Zn dispersion (particle size 100 nm, solid content 10 wt.%).

[0074] Preparation Example 5

[0075] Preparation of CCA-Al dispersion: In a 500 mL ball mill jar containing zirconium beads, add 40 g of CCA-Al from Example 3, 175 mL of deionized water containing 2 g of polyacrylate-butyl acrylate copolymer and 3 g of sodium dodecylbenzenesulfonate, and stir (500 rpm) for 0.5 hours to mix evenly; ball mill at 5000 rpm for 2 hours to obtain a stable CCA-Al dispersion (particle size 110 nm, solid content 20 wt.%).

[0076] Example 1 (Preparation of black toner):

[0077] In a 500 mL pressure reactor, add the following: CCA-Zn aqueous dispersion (5 g, 10 wt.%), wax emulsion (15 g, 20 wt.%), styrene-acrylate emulsion (150 g, 20 wt.%), and carbon black aqueous dispersion (40 g, 15 wt.%, commercially available); then add 100 g of deionized water containing 1 g of sodium dodecylbenzenesulfonate, and mix thoroughly. Adjust the pH of the system to 3 and heat to 50–60 °C, stirring vigorously (2000–5000 rpm) for 1–3 hours. Adjust the pH to 9 and raise the temperature to 95 °C, stirring for 3–5 hours. Cool, filter, wash, and dry to obtain toner (nearly spherical particles, 6–10 μm in size). Add 2% (by weight of the toner) of flowability enhancer silica to obtain black toner suitable for laser printing.

[0078] Using the methods and steps of Example 1 above, the black pigment dispersion was replaced with yellow, magenta, and cyan pigment dispersions respectively (the specific proportions of various materials can be adjusted by conventional means in the art) to obtain yellow, magenta, and cyan toners suitable for color laser printing.

[0079] Example 2

[0080] Except for replacing CCA-Zn with the charge regulator CCA-Al in Preparation Example 5, the other steps are the same as in Example 1.

[0081] Comparative Example 1

[0082] Except for not using the charge regulator CCA-Zn, the other steps are the same as in Example 1.

[0083] Comparative Example 2

[0084] Except for replacing CCA-Zn with DL-N24, a charge regulator widely used in industry, the remaining steps are the same as in Example 1.

[0085] The charge was tested using the standard air blowing method. The electrical performance parameters of the toners in Examples 1-2 and Comparative Examples 1-2 are shown in Tables 1 and 2.

[0086] Table 1. Test results of the change in charge of toner over time in Examples 1-2 and Comparative Examples 1-2.

[0087]

[0088] Table 2. Environmental stability parameters of toner in Examples 1-2 and Comparative Examples 1-2

[0089]

[0090]

[0091] As shown in Tables 1 and 2, within the composition and proportion range of this invention, the electrical performance parameters of the toner prepared by this invention (especially Example 1) are relatively stable; the quality evaluation of the printed samples also basically meets the standard requirements. The test data of Comparative Examples 1-2 in Tables 1 and 2 show that the toner without added charge regulator has poor charging speed, charge, stability, and environmental performance; at the same time, the charge regulator of this invention is superior to the widely used industrial charge regulator DL-N24.

[0092] The embodiments of the present invention have been described above by way of example. However, the scope of protection of the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A negatively charged modifier having a structure as shown in the CCA-Al or CCA-Zn diagram below; 。 2. The negative charge regulating agent of claim 1 is used in the preparation of developer toner for laser printing and electrostatic copying.

3. The method for preparing the negative charge regulator according to claim 1, characterized in that, It includes the following steps: 3,5-Diphenylphthalic acid, a compound containing M, and an alkaline solution were mixed to prepare a compound having the structure shown by the formula CCA-Al or CCA-Zn. The M-containing compound is at least one of zinc chloride and aluminum nitrate.

4. The method according to claim 3, characterized in that, The alkaline solution is an aqueous solution of an alkaline compound, wherein the alkaline compound is sodium hydroxide and / or potassium hydroxide; the mass concentration of the alkaline compound in the alkaline solution is 1-5 wt%.

5. The method according to claim 3, characterized in that, The molar ratio of the M-containing compound, 3,5-diphenylphthalic acid, and the basic compound is 1:(1-4):(1-10).

6. The method according to claim 3, characterized in that, The preparation method further includes: dispersing the compound with the structure shown in formula CCA-Al or CCA-Zn in deionized water containing a dispersant to obtain a dispersion of the compound with the structure shown in formula CCA-Al or CCA-Zn.

7. The method according to claim 6, characterized in that, The dispersant is selected from at least one of sodium polyacrylate, polyacrylate-butyl acrylate copolymer, and sodium dodecylbenzenesulfonate.

8. The method according to claim 7, characterized in that, The dispersion of the compound with the structure shown in formula CCA-Al or CCA-Zn is stable under alkaline conditions and can be demulsified and precipitated under acidic conditions or with the addition of calcium chloride.

9. A type of toner, characterized in that, The raw materials for preparing the toner include compounds with the structure shown in claim 1, such as CCA-Al or CCA-Zn.

10. The toner according to claim 9, characterized in that, The raw materials for preparing the toner include compounds with the structure shown in the formula CCA-Al or CCA-Zn, waxes, resins, and pigments.

11. The toner according to claim 9, characterized in that, The mass ratio of the compound, wax, resin, and pigment with the structure shown in the formula CCA-Al or CCA-Zn is (1-10):(1-20):(60-100):(5-30).

12. The toner according to claim 10, characterized in that, The mass ratio of the compound, wax, resin, and pigment with the structure shown in the formula CCA-Al or CCA-Zn is (1-5):(5-10):(60-90):(10-20).

13. The toner according to claim 10, characterized in that, The wax is selected from paraffin wax, palm wax, refined wax, polyethylene wax, or polypropylene wax; The resin is selected from styrene-propylene copolymer resin or polyester resin.

14. The method for preparing toner according to any one of claims 9-13, characterized in that, The method includes: (1) Mix the compound, wax, resin and pigment with the structure shown in the formula CCA-Al or CCA-Zn, adjust the mixed solution to acidity and heat; (2) Adjust the mixed solution in step (1) to alkaline, heat it, and prepare toner.

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