A preparation method of red electrophoretic particles and its products and applications

Abstract

The present invention relates to a method for preparing red electrophoretic particles, and its products and applications, and belongs to the technical field of preparation of electrophoretic particles. The present invention uses styrene as the basis for polymerization, and simultaneously adds pigment molecules with double bonds and charge control agents, which can be copolymerized with styrene under the action of an initiator, potassium persulfate (KPS), so that the color is embedded in the particles after polymerization. Due to changes in the system, changes in the charge control agent, and changes in the pigment molecules, the preparation method of the present invention can perform color control and charge control of electrophoretic particles in the red color system, and the materials are easy to obtain, which is suitable for large-scale production. The red electrophoretic particles prepared by the present invention have low density, bright colors, a wide color system, stable colors, and stable charges. They are suitable for realizing red full-color gamut color development in future color development processes, and have good application prospects in the preparation of electronic paper.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of electrophoretic particles, and relates to a preparation method of red electrophoretic particles, a product thereof, and an application thereof. Background Art

[0002] Electronic paper displays (E-paper displays) boast thinness, ultra-low power consumption, wide viewing angles, long bistability, and are gentle on the eyes. Their potential applications are widely recognized, particularly in e-books, electronic price tags, electronic bus stops, and electronic business cards, promising benefits in energy conservation, emission reduction, and facilitating people's lives. With the advancement of science and technology, E-paper displays have expanded from their initial black-and-white capabilities to include three- and four-color displays.

[0003] Colored electronic paper is attracting increasing attention, and red, as one of the three primary colors, is being sought in electrophoretic display devices. Therefore, the preparation of red electrophoretic particles is fundamental to achieving full-color display. Literature has already explored the preparation of red electrophoretic particles, some of which use organic polymers as templates, coated with inorganic red pigments, and then sintered to create hollow core-shell materials. The preparation process for such materials is complex and energy-intensive, and the sintering process is likely to result in incomplete core-shell structures. Furthermore, the authors discovered that the colors of these materials were not vibrant enough and had low saturation. Therefore, they sought to prepare the material through organic molecular copolymerization, effectively avoiding the shortcomings of the aforementioned inorganic materials. Summary of the Invention

[0004] In view of this, one of the objects of the present invention is to provide a method for preparing red electrophoretic particles; a second object of the present invention is to provide a red electrophoretic particle; and a third object of the present invention is to provide an application of red electrophoretic particles in the preparation of electronic paper.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] 1. A method for preparing red electrophoretic particles, comprising the following steps:

[0007] Add the charge control agent, styrene, and emulsifier solution to the pigment molecule solution with double bonds, stir and emulsify, then introduce inert gas to form an inert atmosphere, add potassium persulfate (KPS) aqueous solution dropwise under heating and stirring, and stir to initiate copolymerization reaction for 2 to 6 hours to obtain red electrophoretic particles.

[0008] Preferably, the pigment molecule solution is prepared by dispersing Sudan red series pigments in ethanol or water according to a mass volume ratio of 0.2:20-50, g:mL, and stirring to mix them evenly;

[0009] The pigment molecule with a double bond is any one of Sudan I, Sudan II, Sudan III or Sudan IV.

[0010] Preferably, the charge control agent is acrylamide, methacrylic acid or aniline;

[0011] The solvent in the charge control agent solution is styrene.

[0012] Preferably, the emulsifier solution is prepared by dissolving hexadecyltrimethylammonium bromide in water or ethanol solvent at a mass volume ratio of 0.01-0.02:20-50, g:mL, and stirring to mix uniformly;

[0013] The emulsification time is 2 to 16 hours.

[0014] Preferably, the inert gas is Ar or N2.

[0015] Preferably, the concentration of the potassium persulfate (KPS) aqueous solution is 0.005-0.0075 g / mL;

[0016] The potassium persulfate (KPS) aqueous solution is added at a rate of 20 d / min to 20 ml / min, and the temperature during the addition of the potassium persulfate (KPS) aqueous solution is 70° C.

[0017] Preferably, the stirring speed during the polymerization reaction is 300-900 rpm.

[0018] Preferably, when the charge control agent is acrylamide, the mass ratio of the pigment molecule in the pigment molecule solution, the charge control agent, styrene, the emulsifier in the emulsifier solution, and the potassium persulfate (KPS) in the potassium persulfate (KPS) aqueous solution is 0.2:0.05-0.15:4-8:0.01-0.02:0.1-0.15, g:g:mL:g:g;

[0019] When the charge control agent is methacrylic acid, the mass ratio of the pigment molecules in the pigment molecule solution, the charge control agent, styrene, the emulsifier in the emulsifier solution, and the potassium persulfate (KPS) in the potassium persulfate (KPS) aqueous solution is 0.2:300-600:4-8:0.01-0.02:0.1-0.15, g:μL:mL:g:g.

[0020] 2. Red electrophoretic particles prepared according to the above preparation method.

[0021] 3. Application of the above red electrophoretic particles in the preparation of electronic paper.

[0022] The present invention provides a beneficial effect: It discloses a method for preparing red electrophoretic particles. The method primarily uses styrene as a polymerization base, while simultaneously adding a double-bonded pigment molecule (Sudan Red pigments have N=N double bonds suitable for polymerization due to their varying conjugation lengths) and a charge control agent. These pigments copolymerize with styrene under the initiator potassium persulfate (KPS), imbuing the resulting particles with color. The simultaneous addition of styrene and double-bonded pigment molecules imparts the color of the pigment molecules to the resulting electrophoretic particles. Furthermore, the added styrene acts as a shell, forming spherical particles during polymerization, providing a framework and carrier. Due to system changes, charge control agent modifications, and pigment molecule modifications, the method enables both color and charge control of red electrophoretic particles. Furthermore, the readily available materials make it suitable for large-scale production. The red electrophoretic particles prepared by the present invention have low density, bright color, wide color range, stable color, and stable charge. They are suitable for realizing red full color range color display in the future color display process and have good application prospects in the preparation of electronic paper.

[0023] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0025] Figure 1 The macroscopic color of the red electrophoretic particles prepared in Examples 1 to 9;

[0026] Figure 2 1 is a scanning electron microscope image of the red electrophoretic particles prepared in Examples 1 to 9;

[0027] Figure 3 This is a transmission electron microscope image of Example 1. DETAILED DESCRIPTION

[0028] The following describes the embodiments of the present invention through specific specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention. In the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0029] Example 1

[0030] A red electrophoretic particle based on Sudan IV, the specific preparation method is as follows:

[0031] (1) Add a Sudan IV ethanol solution prepared by dissolving 0.2 g of Sudan IV in 20 ml of ethanol to a three-necked flask containing 0.15 g of acrylamide and 4 ml of styrene;

[0032] (2) Continue to add cetyltrimethylammonium bromide solution formed by dissolving 0.01 g of cetyltrimethylammonium bromide in 50 ml of deionized water, dissolve it by ultrasonication, and stir at 600 rpm for 12 hours for emulsification;

[0033] (3) Ar gas was introduced for 30 min, and the mixture was heated to 70 °C. At the same time, the mixture was stirred at a speed of 900 rpm. A potassium persulfate (KPS) aqueous solution prepared by dissolving 0.1 g of potassium persulfate (KPS) in 20 ml of deionized water was slowly added dropwise at a rate of 20 d / min (20 drops / min). The mixture was stirred for 6 h to obtain red Sudan IV-based electrophoretic particles (such as Figure 1 Bottle 1 in the jar).

[0034] Example 2

[0035] A red electrophoretic particle based on Sudan IV, the specific preparation method is as follows:

[0036] (1) Add a Sudan IV aqueous solution prepared by dissolving 0.2 g of Sudan IV in 20 ml of deionized water into a three-necked flask containing 0.15 g of acrylamide and 4 ml of styrene;

[0037] (2) Continue to add cetyltrimethylammonium bromide solution formed by dissolving 0.01 g of cetyltrimethylammonium bromide in 50 ml of deionized water, dissolve it by ultrasonication, and stir at 600 rpm for 12 hours for emulsification;

[0038] (3) Ar gas was introduced for 30 min, and the mixture was heated to 70 °C. At the same time, the mixture was stirred at a speed of 900 rpm. A potassium persulfate (KPS) aqueous solution prepared by dissolving 0.1 g of potassium persulfate (KPS) in 20 ml of deionized water was slowly added dropwise at a rate of 20 d / min (20 drops / min). The mixture was stirred for 6 h to obtain red Sudan IV-based electrophoretic particles (such as Figure 1 Bottle 2 in the jar).

[0039] Example 3

[0040] A red electrophoretic particle based on Sudan IV, the specific preparation method is as follows:

[0041] (1) Add a Sudan IV aqueous solution prepared by dissolving 0.2 g of Sudan IV in 20 ml of deionized water into a three-necked flask containing 300 μL of methacrylic acid and 4 ml of styrene;

[0042] (2) Continue to add cetyltrimethylammonium bromide solution formed by dissolving 0.01 g of cetyltrimethylammonium bromide in 50 ml of deionized water, dissolve it by ultrasonication, and stir at 600 rpm for 12 hours for emulsification;

[0043] (3) Ar gas was introduced for 30 min, and the mixture was heated to 70 °C. At the same time, the mixture was stirred at a speed of 900 rpm. A potassium persulfate (KPS) aqueous solution prepared by dissolving 0.1 g of potassium persulfate (KPS) in 20 ml of deionized water was slowly added dropwise at a rate of 20 d / min (20 drops / min). The mixture was stirred for 6 h to obtain red Sudan IV-based electrophoretic particles (such as Figure 1 Bottle 3 in the jar).

[0044] Example 4

[0045] A red electrophoretic particle based on Sudan I, the specific preparation method is as follows:

[0046] (1) Add a Sudan I solution prepared by dissolving 0.2 g of Sudan I in 20 ml of ethanol into a three-necked flask containing 0.15 g of acrylamide and 4 ml of styrene;

[0047] (2) Continue to add cetyltrimethylammonium bromide solution formed by dissolving 0.01 g of cetyltrimethylammonium bromide in 50 ml of deionized water, dissolve it by ultrasonication, and stir at 600 rpm for 2 h for emulsification;

[0048] (3) Ar gas was introduced for 30 min, and the mixture was heated to 70 °C. At the same time, the mixture was stirred at a speed of 900 rpm. A potassium persulfate (KPS) aqueous solution prepared by dissolving 0.1 g of potassium persulfate (KPS) in 20 ml of deionized water was slowly added dropwise at a rate of 20 d / min (20 drops / min). The mixture was stirred for 4 h to obtain red Sudan IV-based electrophoretic particles (such as Figure 1 4 in the bottle).

[0049] Example 5

[0050] A red electrophoretic particle based on Sudan III, the specific preparation method is as follows:

[0051] (1) Add the Sudan III solution formed by dissolving 0.2 g of Sudan III in 20 ml of ethanol into a three-necked flask containing 0.15 g of acrylamide and 4 ml of styrene, and stir for 30 minutes to mix evenly;

[0052] (2) Continue to add cetyltrimethylammonium bromide solution formed by dissolving 0.01 g of cetyltrimethylammonium bromide in 50 ml of deionized water, dissolve it by ultrasonication, and stir at 600 rpm for 2 h for emulsification;

[0053] (3) Ar gas was introduced for 30 min, and the mixture was heated to 70 °C. At the same time, the mixture was stirred at a speed of 900 rpm. A potassium persulfate (KPS) aqueous solution prepared by dissolving 0.1 g of potassium persulfate (KPS) in 20 ml of deionized water was slowly added dropwise at a rate of 20 d / min (20 drops / min). The mixture was stirred for 4 h to obtain red electrophoretic particles based on Sudan III (such as Figure 1 Bottle 5 in the jar).

[0054] Example 6

[0055] A red electrophoretic particle based on Sudan IV, the specific preparation method is as follows:

[0056] (1) Add the Sudan IV solution formed by dissolving 0.2 g of Sudan IV in 50 ml of ethanol into a three-necked flask containing 0.15 g of acrylamide and 4 ml of styrene, and stir for 30 minutes to mix evenly;

[0057] (2) Continue to add cetyltrimethylammonium bromide solution formed by dissolving 0.01 g of cetyltrimethylammonium bromide in 20 ml of deionized water, dissolve it by ultrasonication, and stir at 600 rpm for 2 h for emulsification;

[0058] (3) Ar gas was introduced for 30 min, and the mixture was heated to 70 °C. At the same time, the mixture was stirred at a speed of 900 rpm. A potassium persulfate (KPS) aqueous solution prepared by dissolving 0.1 g of potassium persulfate (KPS) in 20 ml of deionized water was slowly added dropwise at a rate of 20 d / min (20 drops / min). The mixture was stirred for 4 h to obtain red Sudan IV-based electrophoretic particles (such as Figure 1 6 in the bottle).

[0059] Example 7

[0060] A red electrophoretic particle based on Sudan IV, the specific preparation method is as follows:

[0061] (1) Add the Sudan IV solution formed by dissolving 0.2 g of Sudan IV in 30 ml of ethanol into a three-necked flask containing 0.05 g of acrylamide and 8 ml of styrene, and stir for 30 minutes to mix evenly;

[0062] (2) Continue to add cetyltrimethylammonium bromide solution formed by dissolving 0.02 g of cetyltrimethylammonium bromide in 50 ml of deionized water, dissolve it by ultrasonication, and stir at 600 rpm for 2 h for emulsification;

[0063] (3) Ar gas was introduced for 30 min, and the mixture was heated to 70 °C. At the same time, the mixture was stirred at a speed of 900 rpm. A potassium persulfate (KPS) aqueous solution prepared by dissolving 0.15 g of potassium persulfate (KPS) in 20 ml of deionized water was slowly added dropwise at a rate of 20 d / min (20 drops / min). The mixture was stirred for 4 h to obtain red Sudan IV-based electrophoretic particles (such as Figure 1 Bottle No. 7 in the jar).

[0064] Example 8

[0065] A red electrophoretic particle based on Sudan I, the specific preparation method is as follows:

[0066] (1) Add the Sudan I solution formed by dissolving 0.2 g of Sudan I in 30 ml of ethanol into a three-necked flask containing 600 μL of methacrylic acid and 8 ml of styrene, and stir for 30 minutes to mix thoroughly.

[0067] (2) Continue to add cetyltrimethylammonium bromide solution formed by dissolving 0.01 g of cetyltrimethylammonium bromide in 50 ml of deionized water, dissolve it by ultrasonication, and stir at 600 rpm for 2 h for emulsification;

[0068] (3) Ar gas was introduced for 30 min, and the mixture was heated to 70 °C. At the same time, the mixture was stirred at a speed of 900 rpm. A potassium persulfate (KPS) aqueous solution prepared by dissolving 0.1 g of potassium persulfate (KPS) in 20 ml of deionized water was slowly added dropwise at a rate of 20 d / min (20 drops / min). The mixture was stirred for 4 h to obtain red Sudan IV-based electrophoretic particles (such as Figure 1 8 in the bottle).

[0069] Example 9

[0070] A red electrophoretic particle based on Sudan III, the specific preparation method is as follows:

[0071] (1) Add the Sudan III solution formed by dissolving 0.2 g of Sudan III in 30 ml of ethanol into a three-necked flask containing 600 μL of methacrylic acid and 8 ml of styrene, and stir for 30 minutes to mix evenly;

[0072] (2) Continue to add cetyltrimethylammonium bromide solution formed by dissolving 0.01 g of cetyltrimethylammonium bromide in 50 ml of deionized water, dissolve it by ultrasonication, and stir at 600 rpm for 2 h for emulsification;

[0073] (4) Ar gas was introduced for 30 min, and the mixture was heated to 70 °C. At the same time, the mixture was stirred at 900 rpm. A potassium persulfate (KPS) aqueous solution prepared by dissolving 0.15 g of potassium persulfate (KPS) in 20 ml of deionized water was slowly added dropwise at a rate of 20 d / min (20 drops / min). The mixture was stirred for 4 h to obtain red electrophoretic particles based on Sudan III (such as Figure 1 9 in the bottle).

[0074] Example 10

[0075] A red electrophoretic particle based on Sudan II, the specific preparation method is as follows:

[0076] (1) Add the Sudan II solution formed by dissolving 0.2 g of Sudan II in 20 ml of ethanol into a three-necked flask containing 0.15 g of acrylamide and 4 ml of styrene, and stir for 30 minutes to mix evenly;

[0077] (2) Continue to add cetyltrimethylammonium bromide solution formed by dissolving 0.01 g of cetyltrimethylammonium bromide in 50 ml of deionized water, dissolve it by ultrasonication, and stir at 600 rpm for 12 hours for emulsification;

[0078] (4) Ar gas was introduced for 30 min, and the mixture was heated to 70 °C. At the same time, the mixture was stirred at a speed of 900 rpm. A potassium persulfate (KPS) aqueous solution prepared by dissolving 0.1 g of potassium persulfate (KPS) in 20 ml of deionized water was slowly added dropwise at a rate of 60 d / min (60 drops / min). The mixture was stirred for 6 h to obtain red electrophoretic particles based on Sudan III (such as Figure 1 Bottle 10 in the jar).

[0079] Example 11

[0080] A red electrophoretic particle based on Sudan II, the specific preparation method is as follows:

[0081] (1) Add the Sudan II solution formed by dissolving 0.2 g of Sudan II in 20 ml of ethanol into a three-necked flask containing 300 μL of methacrylic acid and 4 ml of styrene, and stir for 30 minutes to mix thoroughly.

[0082] (2) Continue to add cetyltrimethylammonium bromide solution formed by dissolving 0.01 g of cetyltrimethylammonium bromide in 50 ml of deionized water, dissolve it by ultrasonication, and stir at 600 rpm for 12 hours for emulsification;

[0083] (3) Ar gas was introduced for 30 min, and the mixture was heated to 70 °C. At the same time, the mixture was stirred at a speed of 900 rpm. A potassium persulfate (KPS) aqueous solution prepared by dissolving 0.1 g of potassium persulfate (KPS) in 20 ml of deionized water was slowly added dropwise at a rate of 60 d / min (60 drops / min). The mixture was stirred for 6 h to obtain red electrophoretic particles based on Sudan III (such as Figure 1 Bottle 11 in the ).

[0084] Example 12

[0085] A red electrophoretic particle based on Sudan II, the specific preparation method is as follows:

[0086] (1) Add the Sudan II solution formed by dissolving 0.2 g of Sudan II in 20 ml of ethanol into a three-necked flask containing 300 μL of aniline and 4 ml of styrene, and stir for 30 minutes to mix thoroughly.

[0087] (2) Continue to add cetyltrimethylammonium bromide solution formed by dissolving 0.01 g of cetyltrimethylammonium bromide in 50 ml of deionized water, dissolve it by ultrasonication, and stir at 600 rpm for 12 hours for emulsification;

[0088] (3) Ar gas was introduced for 30 min, and the mixture was heated to 70 °C. At the same time, the mixture was stirred at a speed of 900 rpm. A potassium persulfate (KPS) aqueous solution prepared by dissolving 0.1 g of potassium persulfate (KPS) in 20 ml of deionized water was slowly added dropwise at a rate of 60 d / min (60 drops / min). The mixture was stirred for 6 h to obtain red electrophoretic particles based on Sudan III (such as Figure 1 12 in the bottle).

[0089] Figure 1 The macroscopic color of the red electrophoretic particles prepared in Examples 1 to 12. Figure 1 It can be seen from bottles 1 and 2 that the color of the prepared electrophoretic particles does not change after the solvent for dissolving Sudan Red series pigments is changed from ethanol to deionized water during the preparation of electrophoretic particles; Figure 1 It can be seen from bottles 2 and 3 that the color of the prepared electrophoretic particles changes significantly after the charge control agent is changed from acrylamide to methacrylic acid during the preparation of the electrophoretic particles. Figure 1 Bottles 1 and 4 show that the color of the electrophoretic particles produced also changed significantly when the emulsification time was changed from 12 hours to 2 hours and the copolymerization time was changed from 6 hours to 4 hours. Comparison of the electrophoretic particles in several other bottles also revealed that the apparent color of the electrophoretic particles produced by reacting Sudan I, Sudan II, Sudan III, and Sudan IV, pigment molecules with double bonds, with different charge control agents (methacrylic acid or acrylamide), with different emulsifier emulsification times, and under different polymerization conditions, varied.

[0090] Figure 2 The scanning electron microscope images of the red electrophoretic particles prepared in Examples 1 to 9 are shown in FIG. Figure 2 It can be seen that, during the preparation of electrophoretic particles, acrylamide as a charge control agent is more conducive to producing electrophoretic particles with better dispersion than methacrylic acid as a charge control agent; the greater the ratio of styrene to (water + ethanol) during the preparation process, the slightly larger the size of the prepared electrophoretic particles; the longer the emulsification time, the more uniform the prepared electrophoretic particles; and the more initiator is added during the preparation process, the less uniform the size of the prepared electrophoretic particles. Table 1 shows the charge of the red electrophoretic particles prepared in Examples 1 to 12. As can be seen from Table 1, the red electrophoretic particles prepared by the present invention all have a negative potential.

[0091] Table 1 Charging of the red electrophoretic particles prepared in Examples 1 to 12

[0092]

[0093] Figure 3It is the transmission electron microscope picture of Example 1. Figure 3 It can be seen that the red electrophoretic particles prepared in Example 1 of the present invention have good single-particle dispersibility. At the same time, it can be seen that the prepared red electrophoretic particles have a core and an outer shell, which further proves the occurrence of copolymerization reaction in the preparation process of the present invention and the presence of pigment particles in the prepared electrophoretic particle polymer.

[0094] As can be seen from the images of the electrophoretic particles prepared in the above examples, the electrophoretic particles prepared by the preparation method of the present invention have a wide color range. The color of the electrophoretic particles prepared in the above examples remains essentially unchanged after continued observation, demonstrating that the electrophoretic particles prepared in the above examples have good color stability. Furthermore, the red electrophoretic particles prepared in Examples 1-12 were subjected to multiple charge tests, and the test results were consistent, demonstrating that the red electrophoretic particles prepared in Examples 1-12 have good charge stability.

[0095] In summary, the present invention discloses a method for preparing red electrophoretic particles. The method utilizes styrene as a polymerization base, while simultaneously adding a double-bonded pigment molecule (Sudan Red pigments have N=N double bonds suitable for polymerization due to their varying conjugation lengths) and a charge control agent. These pigments copolymerize with styrene under the initiator potassium persulfate (KPS), imbuing the resulting particles with color. The simultaneous addition of styrene and double-bonded pigment molecules imparts the color of the pigment molecules to the resulting electrophoretic particles. Furthermore, the added styrene acts as a core, forming spherical particles during the polymerization process, providing a framework and carrier. Due to system changes, charge control agent modifications, and pigment molecule variations, the present method enables both color and charge control of red electrophoretic particles. Furthermore, the readily available materials make it suitable for large-scale production. The red electrophoretic particles prepared by the present invention have low density, bright colors, a wide color range, adjustable colors, and adjustable charges. They are suitable for achieving red full-color gamut color display in future color display processes and have good application prospects in the preparation of electronic paper.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for preparing red electrophoretic particles, characterized in that: The preparation method comprises the following steps: The pigment molecule solution is added to the charge control agent, styrene and emulsifier solution, stirred and emulsified, and then an inert gas is introduced to form an inert atmosphere. Under heating and stirring, a potassium persulfate aqueous solution is added dropwise, and the copolymerization reaction is initiated by stirring for 2 to 6 hours to obtain red electrophoretic particles. The pigment molecule solution is prepared by dispersing Sudan red pigments in ethanol or water at a mass volume ratio of 0.2:20-50 g:mL and stirring to mix them evenly. The Sudan Red series pigment is any one of Sudan Red I, Sudan Red III or Sudan Red IV; The charge control agent is acrylamide; The dosage ratio of the pigment molecule in the pigment molecule solution, the charge control agent, styrene, the emulsifier in the emulsifier solution, and the potassium persulfate in the potassium persulfate aqueous solution is 0.2g:0.05-0.15g:4-8ml:0.01-0.02g:0.1-0.15g.

2. The preparation method according to claim 1, characterized in that The preparation method of the emulsifier solution is as follows: dissolving hexadecyltrimethylammonium bromide in water or ethanol solvent according to a mass volume ratio of 0.01-0.02:20-50, g:mL, and stirring to mix evenly; The emulsification time is 2 to 16 hours.

3. The preparation method according to claim 1, characterized in that The inert gas is Ar or N2.

4. The preparation method according to claim 1, characterized in that The concentration of the potassium persulfate aqueous solution is 0.005-0.0075 g / mL; The potassium persulfate aqueous solution was added at a rate of 20 d / min to 20 ml / min, and the temperature during the addition of the potassium persulfate aqueous solution was 70° C.

5. The preparation method according to claim 1, characterized in that The stirring speed during the polymerization reaction is 300-900 rpm.

6. The red electrophoretic particles prepared according to the preparation method according to any one of claims 1 to 5.

7. Use of the red electrophoretic particles according to claim 6 in the preparation of electronic paper.

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