Mixed black electrophoretic particle as well as preparation method and application thereof

Abstract

The invention relates to the technical field of electrophoretic display, in particular to mixed black electrophoretic particles and a preparation method and application thereof. The invention provides a mixed black electrophoretic particle which comprises a first modified black electrophoretic particle and a second modified black electrophoretic particle, the density of the first modified black electrophoretic particle is 0.60-1.38 kg / L, the density of the second modified black electrophoretic particle is 1.40-5.04 kg / L, and the specific surface area of the second modified black electrophoretic particle is larger than 15 m < 2 > / g. The mixed black electrophoretic particle has the excellent properties of high response speed and high contrast ratio, and is beneficial to wide application.

Description

Technical Field

[0001] The present application belongs to the field of electrophoretic display technology, and in particular, relates to mixed black electrophoretic particles and a preparation method and application thereof. Background Art

[0002] Electronic paper is a display device that uses the electrophoretic effect of particles to control image changes. It is commonly seen in daily life, such as electronic price tags and e-book readers. Among them, electrophoretic particles are the core of electronic paper display technology. In current electronic paper displays, black electrophoretic particles generally use single black particles, resulting in the inability of electronic paper displays to take into account both response speed and contrast, affecting the user experience of electronic paper. Summary of the invention

[0003] The present application provides a mixed black electrophoretic particle and a preparation method and application thereof, aiming to solve the problem that in the electrophoretic display liquid provided in the prior art, the black electrophoretic particle only uses a single electrophoretic particle and cannot have both fast response speed and good contrast.

[0004] To achieve this purpose, the technical solution adopted in this application is as follows:

[0005] In a first aspect, the present application provides a mixed black electrophoretic particle, the mixed black electrophoretic particle comprises a modified first black electrophoretic particle and a modified second black electrophoretic particle, the density of the modified first black electrophoretic particle is 0.60 to 1.38 kg / L, the density of the modified second black electrophoretic particle is 1.40 to 5.04 kg / L, and the specific surface area of ​​the modified second black electrophoretic particle is greater than 15 m 2 / g.

[0006] In some embodiments, the density of the modified first black electrophoretic particles differs from the density of the dispersion medium of the electrophoretic fluid by 0% to 100%.

[0007] In some embodiments, the density of the modified first black electrophoretic particles differs from the density of the dispersion medium of the electrophoretic fluid by 0% to 50%.

[0008] In some embodiments, the modified first black electrophoretic particles are first black electrophoretic particles with polymers connected to the surface, and the density of the obtained modified first black electrophoretic particles is 0.60-1.38 kg / L.

[0009] In some embodiments, the modified second black electrophoretic particles are second black electrophoretic particles with a polymer connected to the surface, the density of the obtained modified second black electrophoretic particles is 1.40-5.04 kg / L, and the specific surface area of ​​the modified second black electrophoretic particles is greater than 15 m 2 / g.

[0010] In some embodiments, the polymer includes at least one of polyethylene, polypropylene, polyacrylate, polyurethane, polyester, polysiloxane.

[0011] In some embodiments, the first black electrophoretic particles include at least one of copper chrome black, pigment black 32, antimony sulfide, carbon black, manganese iron black, iron oxide black, iron chrome black, and cobalt black.

[0012] In some embodiments, the second black electrophoretic particles include at least one of copper chrome black, pigment black 32, antimony sulfide, carbon black, manganese iron black, iron oxide black, iron chrome black, and cobalt black.

[0013] In some embodiments, the mass ratio of the modified first black electrophoretic particles to the modified second black electrophoretic particles is 1:0.01-1.

[0014] In some embodiments, the particle size of the modified first black electrophoretic particles is 180-240 nm.

[0015] In some embodiments, the particle size of the modified second black electrophoretic particles is 180-240 nm.

[0016] In a second aspect, the present application provides a method for preparing mixed black electrophoretic particles, comprising the following steps:

[0017] providing at least two types of black electrophoretic particles;

[0018] The black electrophoretic particles are mixed with a silane coupling agent, a polymer monomer, and a solvent, and are subjected to modification reactions respectively. The polymer is grafted onto the surface of the black electrophoretic particles through the silane coupling agent to obtain a modified first black electrophoretic particle and a modified second black electrophoretic particle, wherein the density of the modified first black electrophoretic particle is 0.60 to 1.38 kg / L, the density of the modified second black electrophoretic particle is 1.40 to 5.04 kg / L, and the specific surface area of ​​the modified second black electrophoretic particle is greater than 15 m 2 / g.

[0019] In some embodiments, the silane coupling agent is selected from at least one of a silane comprising a methacryloxy group and a double bond, and a silane comprising an aminoalkyl group and a double bond group.

[0020] In some embodiments, the polymer monomer is selected from at least one of lauryl acrylate, lauryl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, hexyl acrylate, hexyl methacrylate, n-octyl acrylate, n-octyl methacrylate, n-octadecyl acrylate, and n-octadecyl methacrylate.

[0021] In some embodiments, the solvent is selected from at least one of ethanol, benzene, toluene, and xylene.

[0022] In some embodiments, the mass ratio of the black electrophoretic particles to the silane coupling agent, the polymer monomer, and the solvent is 1:0.1-0.3:0.8-2:1-8.

[0023] In a third aspect, the present application provides a black and white dual-color electrophoretic display liquid, which includes the following components in percentage by weight, taking the total mass of the black and white dual-color electrophoretic display liquid as 100%:

[0024]

[0025] The electrophoretic particles include mixed black electrophoretic particles and modified white electrophoretic particles in a mass ratio of 1:1-10, and the mixed black electrophoretic particles are the mixed black electrophoretic particles mentioned above or are prepared by the preparation method of the mixed black electrophoretic particles mentioned above.

[0026] In a fourth aspect, the present application provides an electrophoretic display device, comprising a substrate and an electrophoretic display layer stacked on any one side of the substrate, wherein the electrophoretic display layer is obtained by coating and drying the above-mentioned black and white two-color electrophoretic display liquid.

[0027] The mixed black electrophoretic particles provided in the first aspect of the present application include a modified first black electrophoretic particle with a relatively small density, but it is not easy or impossible to increase the specific surface area to an ideal level by physical or chemical means, and a modified second black electrophoretic particle with a relatively large density and a large specific surface area. The modified first black electrophoretic particle with a small density can increase the swimming speed of the electrophoretic particles and improve the response speed; further, the modified second black electrophoretic particles with a relatively large density and a large specific surface area are provided for mutual use. Since the modified second black electrophoretic particles have a large specific surface area, they can increase the overall black value of the mixed black electrophoretic particles and improve the contrast of the mixed black electrophoretic particles in the electrophoretic system. Therefore, the obtained mixed black electrophoretic particles have excellent properties of fast response speed and high contrast, which is conducive to wide application.

[0028] The second aspect of the present application provides a method for preparing a hybrid black electrophoretic particle, wherein the hybrid black electrophoretic particle is based on a black electrophoretic particle, reacts with a silane coupling agent and a polymer, and the polymer is grafted onto the surface of the black electrophoretic particle through the silane coupling agent as a bridge to achieve modification of the black electrophoretic particle. The preparation method is simple and convenient, the reaction conditions are mild, and it is conducive to industrial application.

[0029] The third aspect of the present application provides a black and white two-color electrophoretic display liquid, which includes electrophoretic particles, a charge control agent, a stabilizer and a dispersion medium, wherein the electrophoretic particles include the above-mentioned mixed black electrophoretic particles; since the above-mentioned mixed black electrophoretic particles have excellent properties of fast response speed and high contrast, the obtained black and white two-color electrophoretic display liquid has a fast response under an electric field and a good coloring effect.

[0030] The electrophoretic display device provided in the fourth aspect of the present application has the characteristics of fast response and high contrast due to the black and white two-color electrophoretic display liquid provided, and the preparation process is simple. Therefore, the electrophoretic display layer of the electrophoretic display device obtained by coating and drying the above-mentioned black and white two-color electrophoretic display liquid has the effects of fast response speed and high contrast, and is easy to prepare with a high success rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 It is a schematic diagram of the electrophoresis phenomenon generated by the electrophoresis display liquid provided in the embodiment of the present application under the action of voltage.

[0033] Figure 2 It is a schematic diagram of a liquid crystal box provided in an embodiment of the present application. DETAILED DESCRIPTION

[0034] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0035] In this application, the term "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0036] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0037] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0038] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0039] The weight of the relevant components mentioned in the embodiment description of the present application can not only refer to the specific content of each component, but also represent the proportional relationship between the weights of the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the embodiment description of the present application, it is within the scope disclosed in the embodiment description of the present application. Specifically, the mass in the embodiment description of the present application can be μg, mg, g, kg and other mass units known in the chemical industry.

[0040] The terms "first" and "second" are used only for descriptive purposes to distinguish objects such as substances from each other, and should not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. For example, without departing from the scope of the embodiments of the present application, the first XX may also be referred to as the second XX, and similarly, the second XX may also be referred to as the first XX. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0041] It is known to those skilled in the art that the core technology of electronic paper display is electrophoretic image display, and its principle is to use colloidal dispersed particles to undergo directional and controllable migration under the action of an electric field, thereby achieving the purpose of displaying specified content. At present, the two-color black and white electrophoretic liquid is composed of positively charged black electrophoretic particles, negatively charged white particles and a dispersion medium. In the prior art, black electrophoretic particles are usually obtained by modifying iron manganese black or copper chromium black particles, and one of the particles is selected as the black electrophoretic particle when configuring the electrophoretic liquid. It can also be understood that in order to obtain excellent display effects, electrophoretic particles should generally have the following characteristics: 1) They should have good optical properties so that they meet very high refractive index, scattering coefficient and very low absorption coefficient; 2) To maintain the bistable characteristics, the density of the electrophoretic particles should be close to the density of the dispersion medium, which can reduce and reduce the aggregation of the particles; 3) The particle size of the particles should be within a reasonable range and have controllable optical properties and aggregation state; 4) The particles cannot be dissolved in organic solvents, and should have good chemical stability in solvents; 5) The surface properties of the particles are controllable and easy to modify to improve the charge adsorption capacity.

[0042] The single black particles currently used are greatly affected by the properties of the raw materials. For example, the density of iron manganese black particles is relatively large, and after modification, their density is greatly different from that of the dispersion medium, which will cause them to migrate slowly during electrophoretic display, affecting the response time of the electronic paper. Due to its optical properties, copper chromium black has a low black value during electrophoretic display and appears gray, resulting in poor contrast. In addition, carbon black is easy to agglomerate in the electrophoretic liquid due to its large specific surface area.

[0043] It can be found that the currently available black and white electrophoretic display liquid is mainly configured using a single modified black particle, and the obtained electrophoretic display liquid cannot have the properties of fast response speed and good contrast at the same time.

[0044] To this end, the first aspect of the embodiment of the present application provides a mixed black electrophoretic particle, the mixed black electrophoretic particle includes a modified first black electrophoretic particle and a modified second black electrophoretic particle, the density of the modified first black electrophoretic particle is 0.60-1.38 kg / L, the density of the modified second black electrophoretic particle is 1.40-5.04 kg / L, and the specific surface area of ​​the modified second black electrophoretic particle is greater than 15 m 2 / g.

[0045] The first aspect of the embodiment of the present application provides a mixed black electrophoretic particle, which includes a modified first black electrophoretic particle with a relatively small density, but it is not easy or impossible to increase the specific surface area to an ideal level by physical or chemical means, and a modified second black electrophoretic particle with a relatively large density and a large specific surface area. The modified first black electrophoretic particle with a small density can increase the swimming speed of the electrophoretic particle and improve the response speed; further, the modified second black electrophoretic particle with a relatively large density and a large specific surface area is provided for mutual use. Since the modified second black electrophoretic particle has a large specific surface area, it can increase the overall black value of the mixed black electrophoretic particle and improve the contrast of the mixed black electrophoretic particle in the electrophoretic system. Therefore, the obtained mixed black electrophoretic particle has excellent properties of fast response speed and high contrast, which is conducive to wide application.

[0046] In the mixed black electrophoretic particles, the density of the modified first black electrophoretic particles is 0.60 to 1.38 kg / L. The density of the modified first black electrophoretic particles is relatively small, in order to better improve the swimming speed of the electrophoretic particles and to improve the response speed. In some embodiments, the density of the modified first black electrophoretic particles includes but is not limited to 0.6 kg / L, 0.75 kg / L, 0.85 kg / L, 0.97 kg / L, 1.07 kg / L, 1.12 kg / L, 1.20 kg / L; it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0047] In some embodiments, the density of the modified first black electrophoretic particle differs from the density of the dispersion medium of the electrophoretic liquid by 0% to 100%. Controlling the density of the modified first black electrophoretic particle to be close to the density of the dispersion medium of the electrophoretic liquid can increase the swimming speed of the modified first black electrophoretic particle, increase the response speed, and shorten the response time.

[0048] In some embodiments, the density of the modified first black electrophoretic particle differs from the density of the dispersion medium of the electrophoretic liquid by 0% to 50%. When the density of the modified first black electrophoretic particle is closer to the density of the dispersion medium of the electrophoretic liquid, the swimming speed of the modified first black electrophoretic particle is higher, the corresponding speed is higher, and the response time is shorter. Specific surface area refers to the area per unit mass of material. For example, if there are 10 particles in 1g of particles, it is the surface area of ​​these ten particles. If there is only 1 particle in 1g of particles, it is the surface area of ​​this particle. Since the specific surface area is an inherent property of the raw material of the particle, it is not easy to change this parameter by subsequent modification. Among them, the modified first black electrophoretic particle is a particle that is difficult or impossible to increase the specific surface area to an ideal degree by physical or chemical means. Therefore, the specific surface area of ​​the modified first black electrophoretic particle is not required, but the second black electrophoretic particle is modified by compounding; the purpose of adding the modified second black electrophoretic particle is to compensate for the first modified electrophoretic particle with a lower density but a larger specific surface area, and the specific surface area cannot be increased to an ideal degree by physical or chemical means. In the mixed black electrophoretic particles, the density of the modified second black electrophoretic particles is 1.40 to 5.04 kg / L, and the specific surface area of ​​the modified second black electrophoretic particles is greater than 15 m 2 / g. Since black particles achieve the purpose of displaying black by absorbing light sources, a larger specific surface area means that the particle surface is not smooth, the more gaps there are, the less light is reflected, and the light is captured by the black particles and cannot be reflected. However, the larger the specific surface area of ​​the particles, the higher the surface energy of the particles, which makes them easy to accumulate and agglomerate, and it is not easy to modify them to the ideal density by chemical or physical means. Therefore, the modified second black electrophoretic particles provided are black particles with a larger density and a larger specific surface area, which can supplement the black value of the modified first black electrophoretic particles and improve the contrast.

[0049] In some embodiments, the modified first black electrophoretic particles are black electrophoretic particles with polymers connected to their surfaces, and the density of the modified first black electrophoretic particles is 0.60-1.38 kg / L. The first black electrophoretic particles are modified with polymers to obtain a density of 0.60-1.38 kg / L.

[0050] In some embodiments, the first black electrophoretic particles include at least one of copper chrome black, pigment black 32, antimony sulfide, carbon black, manganese iron black, iron oxide black, iron chrome black, and cobalt black.

[0051] In some embodiments, the modified second black electrophoretic particles are black electrophoretic particles with a polymer connected to the surface. The density of the modified second black electrophoretic particles obtained by modifying the second black electrophoretic particles with the polymer is 1.40 to 5.04 kg / L, and the specific surface area of ​​the modified second black electrophoretic particles is greater than 15 m 2 / g.

[0052] In some embodiments, the second black electrophoretic particles include at least one of copper chrome black, pigment black 32, antimony sulfide, carbon black, manganese iron black, iron oxide black, iron chrome black, and cobalt black.

[0053] In some embodiments, the polymer includes at least one of polyethylene, polypropylene, polyacrylate, polyurethane, polyester, polysiloxane.

[0054] In a specific embodiment, the first black electrophoretic particle and the second black electrophoretic particle can be modified by the same type of black electrophoretic particle or different types of black electrophoretic particles; in the process of modifying the first black electrophoretic particle or the second black electrophoretic particle, the polymers used can be selected to be the same type or different types, specifically: it is necessary to select a suitable polymer for modification according to the specifications and performance descriptions provided by the manufacturer of the black particles, and finally ensure that the density of the modified first black electrophoretic particle is 0.60-1.38 kg / L; the density of the modified second black electrophoretic particle is 1.40-5.04 kg / L, and the specific surface area of ​​the modified second black electrophoretic particle is greater than 15 m 2 / g.

[0055] In some embodiments, the mass ratio of the modified first black electrophoretic particles to the modified second black electrophoretic particles is 1:0.01 to 1. Compared with the modified second black electrophoretic particles, the modified first black electrophoretic particles have a smaller specific surface area and therefore have a weaker light capture capability, and will appear gray when displayed black, which can easily lead to a low contrast ratio. Therefore, if the amount of the modified first black electrophoretic particles added is too small, the obtained mixed black electrophoretic particles can improve the contrast ratio, but the response time will be greatly slowed down; if the amount of the modified first black electrophoretic particles added is too large, the obtained mixed black electrophoretic particles will have a fast response speed during use, but a poor contrast ratio and will be difficult to distinguish.

[0056] In some specific embodiments, the mass ratio of the modified first black electrophoretic particles to the modified second black electrophoretic particles includes but is not limited to 1:0.01, 1:0.02, 1:0.03, 1:0.04, 1:0.05, 1:0.06, 1:0.07, 1:0.08, 1:0.09, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9 or 1:1; it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0057] In some embodiments, the particle size of the modified first black electrophoretic particle is 180 to 240 nm. In some specific embodiments, the particle size of the modified first black electrophoretic particle includes, but is not limited to, typical but non-limiting values ​​such as 180 nm, 185 nm, 190 nm, 195 nm, 200 nm, 205 nm, 210 nm, 215 nm, 220 nm, 225 nm, 230 nm, 235 nm, and 240 nm, and other values ​​not listed in the numerical range are also applicable.

[0058] In some embodiments, the particle size of the modified second black electrophoretic particles is 180 to 240 nm. In some specific embodiments, the particle size of the modified second color electrophoretic particles includes, but is not limited to, typical but non-limiting values ​​such as 180 nm, 185 nm, 190 nm, 195 nm, 200 nm, 205 nm, 210 nm, 215 nm, 220 nm, 225 nm, 230 nm, 235 nm, and 240 nm, and other values ​​not listed in the numerical range are also applicable.

[0059] In some embodiments, the modified first black electrophoretic particles and the modified second black electrophoretic particles have the same particle size.

[0060] In some embodiments, the provided mixed black electrophoretic particles may further include at least one type of black electrophoretic particles such as modified third black electrophoretic particles, modified fourth black electrophoretic particles, and modified fifth black electrophoretic particles. It is only necessary to ensure that the obtained mixed black electrophoretic particles include two types of modified black electrophoretic particles, wherein the density of the type one black electrophoretic particles is 0.60 to 1.38 kg / L, the density of the type two black electrophoretic particles is 1.40 to 5.04 kg / L, and the specific surface area of ​​the type two black electrophoretic particles is greater than 15 m 2 / g.

[0061] In a second aspect, the present application provides a method for preparing mixed black electrophoretic particles, comprising the following steps:

[0062] S01. Provide at least two black electrophoretic particles;

[0063] S02. The black electrophoretic particles are mixed with a silane coupling agent, a polymer monomer, and a solvent, and are subjected to modification reactions respectively. The polymer is grafted onto the surface of the black electrophoretic particles by the silane coupling agent to obtain a modified first black electrophoretic particle and a modified second black electrophoretic particle, wherein the density of the modified first black electrophoretic particle is 0.60 to 1.38 kg / L, the density of the modified second black electrophoretic particle is 1.40 to 5.04 kg / L, and the specific surface area of ​​the modified second black electrophoretic particle is greater than 15 m 2 / g.

[0064] The second aspect of the embodiment of the present application provides a method for preparing mixed black electrophoretic particles, wherein the mixed black electrophoretic particles are based on black electrophoretic particles, reacted with a silane coupling agent and a polymer, and the polymer is grafted on the surface of the black electrophoretic particles through a silane coupling agent as a bridge to achieve modification of the black electrophoretic particles. The preparation method is simple and convenient, and the reaction conditions are mild, which is conducive to industrial application. In the reaction solution, the silane coupling agent can bridge the polymer and the particles, and the polymer itself does not react directly with the particles. Therefore, the electrophoretic particles can be prepared using a one-pot method, eliminating the steps of silane coupling agent modification and then polymer modification, and no long vacuum drying process is required, saving preparation time and cost.

[0065] In step S01 , at least two kinds of black electrophoretic particles are provided.

[0066] In some embodiments, the black electrophoretic particles include at least one of copper chrome black, pigment black 32, antimony sulfide, carbon black, manganese iron black, iron oxide black, iron chrome black, and cobalt black. The selection of particles is very important, and examples need to be screened according to the specific surface area of ​​the particles provided by the supplier. Because different material manufacturing methods will result in the same particles having different specific surface areas, therefore, it is necessary to select specific particles for use according to the material specifications provided by the supplier.

[0067] In a specific embodiment, based on the already clarified density of the modified first black electrophoretic particle being 0.60-1.38 kg / L, the density of the modified second black electrophoretic particle being 1.40-5.04 kg / L and the specific surface area being greater than 15 m 2 / g characteristics, it can be clearly seen that the density and specific surface area of ​​the modified first black electrophoretic particles are smaller than those of the modified second black electrophoretic particles. Therefore, the density and specific surface area of ​​the black electrophoretic particle raw material selected for preparing the modified first black electrophoretic particles are smaller than those of the black electrophoretic particle raw material used for preparing the modified second black electrophoretic particles. In the actual operation process, the black electrophoretic particles can be selected after being compared one by one according to the specific material specifications of the black electrophoretic particles.

[0068] During the modification process, the two black particles can be modified separately or mixed together.

[0069] In step S02, the black electrophoretic particles are mixed with a silane coupling agent, a polymer monomer, and a solvent, and modification reactions are performed respectively. The polymer is grafted onto the surface of the black electrophoretic particles by the silane coupling agent to obtain a modified first black electrophoretic particle and a modified second black electrophoretic particle, wherein the density of the modified first black electrophoretic particle is 0.60 to 1.38 kg / L, the density of the modified second black electrophoretic particle is 1.40 to 5.04 kg / L, and the specific surface area of ​​the modified second black electrophoretic particle is greater than 15 m 2 / g.

[0070] In some embodiments, the silane coupling agent is selected from at least one of a silane comprising a methacryloxy group and a double bond, and a silane comprising an aminoalkyl group and a double bond group.

[0071] In one embodiment, the silane containing a methacryloxy group includes, but is not limited to, at least one of methacryloxypropyltrimethoxysilane (e.g., KH-570), methacryloxypropylmethyldimethoxysilane (e.g., KH-571), methacryloxypropylmethyldiethoxysilane, and methacryloxypropylmethyldiethoxysilane.

[0072] In one embodiment, the silane containing an aminoalkyl group is, for example, but not limited to, at least one of diethylenetriaminopropyltrimethoxysilane, vinylbenzylaminoethylaminopropyltrimethoxysilane, and N-[3-(trimethoxysilyl)propyl]-N'-4-(vinylbenzyl)ethylenediamine hydrochloride.

[0073] In some embodiments, the polymer monomer is selected from at least one of lauryl acrylate, lauryl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, hexyl acrylate, hexyl methacrylate, n-octyl acrylate, n-octyl methacrylate, n-octadecyl acrylate, and n-octadecyl methacrylate.

[0074] After the reaction, the polymer connected to the surface of the electrophoretic particle includes but is not limited to at least one of polyethylene, polypropylene, polyacrylate, polyurethane, polyester, and polysiloxane. The polymer has bistability for the electrophoretic display, and more side chains or longer polymers are more preferably used as stabilizers.

[0075] In some embodiments, the solvent is selected from at least one of ethanol, benzene, toluene, and xylene.

[0076] In some embodiments, the mass ratio of black electrophoretic particles to silane coupling agent, polymer monomer, and solvent is 1: 0.1-0.3: 0.8-2: 1-8. When the ratio of electrophoretic particles to solvent, silane coupling agent, and polymer monomer is not appropriate, the electrophoretic particles have poor charge and dispersion, which affects their swimming effect in the electrophoretic solution. In some preferred embodiments, the mass ratio of black electrophoretic particles to silane coupling agent, polymer monomer, and solvent is 1: 0.1-0.2: 1-1.5: 1-3.

[0077] In some specific embodiments, the mass ratio of black electrophoretic particles to silane coupling agent, polymer monomer, and solvent includes but is not limited to any one of 1:0.1:0.8:1, 1:0.2:1:3, 1:0.25:1.5:5, and 1:0.3:2:8; but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0078] Finally, the modified first black electrophoretic particles and the modified second black electrophoretic particles are obtained, wherein the density of the modified first black electrophoretic particles is 0.60-1.38 kg / L, the density of the modified second black electrophoretic particles is 1.40-5.04 kg / L, and the specific surface area of ​​the modified second black electrophoretic particles is greater than 15 m 2 / g.

[0079] The third aspect of the present application provides a black and white two-color electrophoretic display liquid (such as Figure 1 ), the total mass of the black and white two-color electrophoresis display liquid is 100%, including the following components in percentage by weight:

[0080] Electrophoretic particles 10% to 50%,

[0081] Charge control agent 2% to 15%,

[0082] Stabilizer 0.1%~1%,

[0083] Dispersing medium 46%~87.9%;

[0084] The electrophoretic particles include mixed black electrophoretic particles and modified white electrophoretic particles in a mass ratio of 1:1-10, and the mixed black electrophoretic particles are the mixed black electrophoretic particles mentioned above or are prepared by the preparation method of the mixed black electrophoretic particles mentioned above.

[0085] A third aspect of an embodiment of the present application provides a black and white two-color electrophoretic display liquid, which includes electrophoretic particles, a charge control agent, a stabilizer and a dispersion medium, wherein the electrophoretic particles include the above-mentioned mixed black electrophoretic particles; since the above-mentioned mixed black electrophoretic particles have excellent properties of fast response speed and high contrast, the obtained black and white two-color electrophoretic display liquid has a fast response under an electric field and a good coloring effect.

[0086] The total mass of the black and white two-color electrophoretic display liquid is 100%, including electrophoretic particles with a weight percentage of 10% to 50%. In some embodiments, the total mass of the black and white two-color electrophoretic display liquid is 100%, and the weight percentage of the electrophoretic particles includes but is not limited to 10%, 15%, 20%, 25%, 30%, 35%, 45%, 50%; it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0087] The electrophoretic particles include mixed black electrophoretic particles and modified white electrophoretic particles, and the mixed black electrophoretic particles are the mixed black electrophoretic particles mentioned above.

[0088] In some embodiments, the mass ratio of the mixed black electrophoretic particles to the modified white electrophoretic particles is 1:1 to 10. When the mass ratio of the mixed black electrophoretic particles to the modified white electrophoretic particles is inappropriate, the covering power of the mixed black electrophoretic particles and the modified white electrophoretic particles is weak, and the difference between the positive and negative charges is large, which affects the optical performance of the device. In some preferred embodiments, the mass ratio of the mixed black electrophoretic particles to the modified white electrophoretic particles is 1:2-6.

[0089] In some specific embodiments, the mass ratio of the mixed black electrophoretic particles and the modified white electrophoretic particles includes but is not limited to 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10; but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0090] In some embodiments, the modified white electrophoretic particles are selected from titanium dioxide, wherein the particle size of the titanium dioxide is 50-200 nm.

[0091] The total mass of the black and white two-color electrophoretic display liquid is 100%, and the weight percentage of the charge control agent is 2% to 15%. In some embodiments, the total mass of the black and white two-color electrophoretic display liquid is 100%, and the weight percentage of the charge control agent includes but is not limited to 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%; it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0092] In some embodiments, the charge control agent is selected from polydodecyl hydroxystearic acid dispersants. In some specific embodiments, the charge control agent is selected from at least one of Solsperse 3000, Solsperse 8000, Solsperse 13300, Solsperse 17000 and Solsperse 19000.

[0093] The total mass of the black and white two-color electrophoresis display liquid is 100%, and the weight percentage of the stabilizer is 0.1% to 1%. In some embodiments, the total mass of the black and white two-color electrophoresis display liquid is 100%, and the weight percentage of the stabilizer includes but is not limited to 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%; it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0094] In some embodiments, the stabilizer is selected from at least one of polymer resin polyisobutylene, glycol ester, acetylene glycol, alkyl amine, and alkanolamide.

[0095] The total mass of the black and white two-color electrophoresis display liquid is 100%, including the dispersion medium with a weight percentage of 46% to 87.9%.

[0096] In some embodiments, the commonly used dispersion medium can be an organic halide and a halogen-containing oligomer, such as tetrafluorodibromoethylene, tetrachloroethylene, trifluorochloroethylene, 1,2,4-trichlorobenzene, carbon tetrachloride, polytrifluorochloroethylene (degree of polymerization 2 to 10), perfluoroether, etc.; the dispersion medium can also be silicone oil and a straight-chain or branched saturated hydrocarbon, such as octamethyl epoxysilane, high molecular weight epoxysilane, polymethylphenylsiloxane, hexamethyldisiloxane, dodecane, n-tetradecane, naphtha, Isopar series and Norpar series of ExxonMobil Chemical Company of the United States, etc. Specifically in the embodiment of the present application, the dispersion medium is preferably selected from the Isopar series isomeric alkane solvent. The Isopar series isomeric alkanes have a higher boiling point and a lower volatility, a lower dielectric constant, a lower conductivity, good optical and chemical stability, a suitable viscosity, low toxicity and environmental friendliness. In the Isopar series, each reagent has differences in physical properties such as boiling point, melting point, flash point and viscosity.

[0097] In some specific embodiments, the dispersion medium is selected from at least one of Isopar B, Isopar E, Isopar G, Isopar H, Isopar L and Isopar M.

[0098] Furthermore, a method for preparing a black and white dual-color electrophoresis display liquid is provided, comprising the following steps:

[0099] G01. Providing each component according to the above-mentioned black and white two-color electrophoresis display liquid,

[0100] G02. Evenly mix the mixed black electrophoretic particles, modified white electrophoretic particles, charge control agent, stabilizer and dispersion medium, and then perform ball milling reaction, and then separate the ball milling liquid to obtain a black and white dual-color electrophoretic display liquid.

[0101] In step G01, various components are provided according to the above-mentioned black and white two-color electrophoretic display liquid. The specific types and addition amounts are as discussed above, and will not be described again here to save space.

[0102] In step G02, the mixed black electrophoretic particles, the modified white electrophoretic particles, the charge control agent, the stabilizer and the dispersion medium are uniformly mixed and then subjected to ball milling reaction, and the ball milling liquid is separated to obtain a black and white dual-color electrophoretic display liquid.

[0103] In some embodiments, the method for preparing the modified white electrophoretic particles comprises the following steps:

[0104] White electrophoretic particles are provided, and the white electrophoretic particles are mixed with a silane coupling agent, a polymer monomer, and a solvent to perform a modification reaction, and the polymer is grafted onto the surface of the white electrophoretic particles through the silane coupling agent.

[0105] In some embodiments, the mass ratio of white electrophoretic particles to silane coupling agent, polymer monomer, and solvent is 1: 0.1-0.3: 0.8-2: 1-8. When the ratio of electrophoretic particles to solvent, silane coupling agent, and polymer monomer is not appropriate, the electrophoretic particles have poor charge and dispersion, which affects their swimming effect in the electrophoretic solution. In some preferred embodiments, the mass ratio of white electrophoretic particles to silane coupling agent, polymer monomer, and solvent is 1: 0.1-0.2: 1-1.5: 1-3.

[0106] In some specific embodiments, the mass ratio of white electrophoretic particles to silane coupling agent, polymer monomer, and solvent includes but is not limited to any one of 1:0.1:0.8:1, 1:0.2:1:3, 1:0.25:1.5:5, and 1:0.3:2:8; but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0107] In the step of modifying the black electrophoretic particles and the white electrophoretic particles, the types of silane coupling agent, polymer monomer, and solvent used are the same; in order to save space, they will not be repeated here. In a fourth aspect of the embodiment of the present application, an electrophoretic display device is provided, the electrophoretic display device includes a substrate and an electrophoretic display layer stacked on either side of the substrate, wherein the electrophoretic display layer is obtained by coating and drying the above-mentioned black and white two-color electrophoretic display liquid.

[0108] The electrophoretic display device provided in the fourth aspect of the embodiment of the present application has the characteristics of fast response and high contrast due to the black and white two-color electrophoretic display liquid provided, and the preparation process is simple. Therefore, the electrophoretic display layer of the electrophoretic display device obtained by coating and drying the above-mentioned black and white two-color electrophoretic display liquid has the effects of fast response speed and high contrast, and is easy to prepare with a high success rate.

[0109] The following describes the invention in conjunction with specific embodiments.

[0110] The liquid crystal cell used in the following embodiments (such as Figure 2 As shown), the liquid crystal boxes are: two pieces of conductive glass with a size of 15.00mm×10.00mm×1.10mm are separated by an insulating film with a size of 10mm×10mm and a thickness of 20μm, and a 10mm×10mm square opening is opened in the middle as a display window. The electrophoretic liquid is poured into the display window, which is sealed with UV glue, and the conductive glass is connected to a power source with a conductive clip.

[0111] Example A1

[0112] Mixed black electrophoretic particles

[0113] The mixed black electrophoretic particles include 1g of modified first black electrophoretic particles and 1g of modified second black electrophoretic particles, wherein the modified first black electrophoretic particles are modified copper chromium black particles with a density of 0.96kg / L, and the density of the modified first black electrophoretic particles differs by 20% from the density of the dispersion medium of the electrophoretic liquid; the specific surface area is 2.7m 2 / g; the modified second black electrophoretic particles are modified manganese iron black particles with a density of 3.82kg / L and a specific surface area of ​​15.2m 2 / g.

[0114] Preparation method of modified first black electrophoretic particles (modified copper chrome black particles): Take 10g of copper chrome black raw material and 100mL of toluene solvent, add the mixed solvent and copper chrome black raw material into a flask. Stir water and silane coupling agent in a beaker for 10min and add them into the flask, continue to disperse for 30min, then add 50g of methyl methacrylate, stir at room temperature for 1h, and the system is a black turbid liquid. Then heat the system to 70℃, slowly add initiator, and keep the reaction at this temperature overnight. After the insulation is completed, wait until the system cools to room temperature, clean the grafted copper chrome black particles, and vacuum dry them for use.

[0115] Preparation method of modified second black electrophoretic particles (modified manganese iron black particles): Take 10g of manganese iron black raw material and 100mL of toluene solvent, add the mixed solvent and manganese iron black raw material into a flask. Stir water and silane coupling agent in a beaker for 10 minutes and then add them into the flask, continue to disperse for 30 minutes, then add 50g of methyl methacrylate, stir at room temperature for 1 hour, and the system is a black turbid liquid. Then heat the system to 70°C, slowly add the initiator, and keep the reaction at this temperature overnight. After the insulation is completed, wait until the system cools to room temperature, clean the grafted manganese iron black particles, and vacuum dry them for use.

[0116] Example A2

[0117] Mixed black electrophoretic particles

[0118] The mixed black electrophoretic particles include 1g of modified first black electrophoretic particles and 0.05g of modified second black electrophoretic particles, wherein the modified first black electrophoretic particles are modified copper chromium black particles with a density of 0.96kg / L, and the density of the modified first black electrophoretic particles differs by 20% from the density of the dispersion medium of the electrophoretic liquid; the specific surface area is 2.7m 2 / g; the modified second black electrophoretic particles are modified manganese iron black particles with a density of 3.82kg / L and a specific surface area of ​​15.2m 2 / g.

[0119] The preparation method of the modified first black electrophoretic particles (modified copper chromium black particles) is the same as the preparation method of the modified first black electrophoretic particles (modified copper chromium black particles) in Example A1.

[0120] The preparation method of the modified second black electrophoretic particles (modified manganese iron black particles) is the same as the preparation method of the modified second black electrophoretic particles (modified manganese iron black particles) of Example A1.

[0121] Example A3

[0122] Mixed black electrophoretic particles

[0123] The mixed black electrophoretic particles include 1g of modified first black electrophoretic particles and 0.2g of modified second black electrophoretic particles, wherein the modified first black electrophoretic particles are modified copper chromium black particles with a density of 0.96kg / L, and the density of the modified first black electrophoretic particles differs by 20% from the density of the dispersion medium of the electrophoretic liquid; the specific surface area is 2.7m 2 / g; the modified second black electrophoretic particles are modified manganese iron black particles with a density of 3.82kg / L and a specific surface area of ​​15.2m 2 / g.

[0124] The preparation method of the modified first black electrophoretic particles (modified copper chromium black particles) is the same as the preparation method of the modified first black electrophoretic particles (modified copper chromium black particles) in Example A1.

[0125] The preparation method of the modified second black electrophoretic particles (modified manganese iron black particles) is consistent with the preparation method of the modified second black electrophoretic particles (modified manganese iron black particles) of Example A1.

[0126] Example A4

[0127] Mixed black electrophoretic particles

[0128] The mixed black electrophoretic particles include 1g of modified first black electrophoretic particles and 0.5g of modified second black electrophoretic particles, wherein the modified first black electrophoretic particles are modified copper chromium black particles with a density of 0.96kg / L, and the density of the modified first black electrophoretic particles differs by 20% from the density of the dispersion medium of the electrophoretic liquid; the specific surface area is 2.7m 2 / g; the modified second black electrophoretic particles are modified manganese iron black particles with a density of 3.82kg / L and a specific surface area of ​​15.2m 2 / g.

[0129] The preparation method of the modified first black electrophoretic particles (modified copper chromium black particles) is the same as the preparation method of the modified first black electrophoretic particles (modified copper chromium black particles) in Example A1.

[0130] The preparation method of the modified second black electrophoretic particles (modified manganese iron black particles) is consistent with the preparation method of the modified second black electrophoretic particles (modified manganese iron black particles) of Example A1.

[0131] Example A5

[0132] Mixed black electrophoretic particles

[0133] The mixed black electrophoretic particles include 1g of modified first black electrophoretic particles and 0.5g of modified second black electrophoretic particles, wherein the modified first black electrophoretic particles are modified copper chromium black particles with a density of 0.96kg / L, and the density of the modified first black electrophoretic particles differs by 20% from the density of the dispersion medium of the electrophoretic liquid; the specific surface area is 2.7m 2 / g ； The modified second black electrophoretic particles are modified pigment black 32 particles with a density of 1.476 kg / L and a specific surface area of ​​39 m 2 / g.

[0134] The preparation method of the modified first black electrophoretic particles (modified copper chromium black particles) is the same as the preparation method of the modified first black electrophoretic particles (modified copper chromium black particles) in Example A1.

[0135] Preparation method of modified second black electrophoretic particles (modified pigment black 32 particles): Take 10g of pigment black 32 raw material and 100mL of toluene solvent, add the mixed solvent and pigment black 32 raw material into a flask, then add 50g of styrene, stir at room temperature for 1h, and the system is a black turbid liquid. Then heat the system to 70°C, slowly add initiator, and keep the temperature at this temperature for overnight reaction. After the insulation is completed, wait for the system to cool to room temperature, clean the grafted pigment black 32 particles, and vacuum dry them for use.

[0136] Example A6

[0137] Mixed black electrophoretic particles

[0138] The mixed black electrophoretic particles include 1g of modified first black electrophoretic particles and 0.05g of modified second black electrophoretic particles, wherein the modified first black electrophoretic particles are modified copper chromium black particles with a density of 0.96kg / L, and the density of the modified first black electrophoretic particles differs by 20% from the density of the dispersion medium of the electrophoretic liquid; the specific surface area is 2.7m 2 / g ； The modified second black electrophoretic particles are modified pigment black 32 particles with a density of 1.476 kg / L and a specific surface area of ​​39 m 2 / g.

[0139] The preparation method of the modified first black electrophoretic particles (modified copper chromium black particles) is the same as the preparation method of the modified first black electrophoretic particles (modified copper chromium black particles) in Example A1.

[0140] The preparation method of the modified second black electrophoretic particles (modified pigment black 32 particles) is consistent with the preparation method of the modified second black electrophoretic particles (modified pigment black 32 particles) of Example A5.

[0141] Example A7

[0142] Mixed black electrophoretic particles

[0143] The mixed black electrophoretic particles include 1g of modified first black electrophoretic particles and 1g of modified second black electrophoretic particles, wherein the modified first black electrophoretic particles are modified copper chromium black particles with a density of 0.96kg / L, and the density of the modified first black electrophoretic particles differs by 20% from the density of the dispersion medium of the electrophoretic liquid; the specific surface area is 2.7m 2 / g ； The modified second black electrophoretic particles are modified pigment black 32 particles with a density of 1.476 kg / L and a specific surface area of ​​39 m 2 / g.

[0144] The preparation method of the modified first black electrophoretic particles (modified copper chromium black particles) is the same as the preparation method of the modified first black electrophoretic particles (modified copper chromium black particles) in Example A1.

[0145] The preparation method of the modified second black electrophoretic particles (modified pigment black 32 particles) is consistent with the preparation method of the modified second black electrophoretic particles (modified pigment black 32 particles) of Example A5.

[0146] Example A8

[0147] Mixed black electrophoretic particles

[0148] The mixed black electrophoretic particles include 1g of modified first black electrophoretic particles and 0.2g of modified second black electrophoretic particles, wherein the modified first black electrophoretic particles are modified copper chromium black particles with a density of 0.96kg / L, and the density of the modified first black electrophoretic particles differs by 20% from the density of the dispersion medium of the electrophoretic liquid; the specific surface area is 2.7m 2 / g ； The modified second black electrophoretic particles are modified pigment black 32 particles with a density of 1.476 kg / L and a specific surface area of ​​39 m 2 / g.

[0149] The preparation method of the modified first black electrophoretic particles (modified copper chromium black particles) is the same as the preparation method of the modified first black electrophoretic particles (modified copper chromium black particles) in Example A1.

[0150] The preparation method of the modified second black electrophoretic particles (modified pigment black 32 particles) is consistent with the preparation method of the modified second black electrophoretic particles (modified pigment black 32 particles) of Example A5.

[0151] Embodiment A9

[0152] Mixed black electrophoretic particles

[0153] The mixed black electrophoretic particles include 5g of modified first black electrophoretic particles and 5g of modified second black electrophoretic particles, wherein the modified first black electrophoretic particles are modified carbon black particles with a density of 0.94kg / L, and the density of the modified first black electrophoretic particles differs from the density of the dispersion medium of the electrophoretic liquid by 17.5%; the specific surface area is 14m 2 / g; the modified second black electrophoretic particles are modified manganese iron black particles with a density of 3.82kg / L and a specific surface area of ​​15.2m 2 / g.

[0154] Preparation method: Take 5g of manganese iron black raw material and 5g of carbon black, add 100mL of toluene solvent, add the mixed solvent and black particles into a flask, then add 50g of methyl methacrylate and a certain amount of silane coupling agent, stir at room temperature for 1h, and the system is a black turbid liquid. Then heat the system to 70℃, slowly add the initiator, and keep the temperature at this temperature for overnight reaction. After the insulation is completed, wait for the system to cool to room temperature, wash the grafted manganese iron black particles and carbon black particles, and vacuum dry them for use.

[0155] Embodiment A10

[0156] Mixed black electrophoretic particles

[0157] The mixed black electrophoretic particles include 10g of modified first black electrophoretic particles and 5g of modified second black electrophoretic particles, wherein the modified first black electrophoretic particles are modified carbon black particles with a density of 0.94kg / L, and the density of the modified first black electrophoretic particles differs from the density of the dispersion medium of the electrophoretic liquid by 17.5%; the specific surface area is 14m 2 / g; the modified second black electrophoretic particles are modified manganese iron black particles with a density of 3.82kg / L and a specific surface area of ​​15.2m 2 / g.

[0158] Preparation method: Take 10g of manganese iron black raw material and 5g of carbon black, add 150mL of toluene solvent, add the mixed solvent and black particles into a flask, then add 75g of methyl methacrylate and a certain amount of silane coupling agent, stir at room temperature for 1h, and the system is a black turbid liquid. Then heat the system to 70℃, slowly add the initiator, and keep the temperature at this temperature for overnight reaction. After the insulation is completed, wait for the system to cool to room temperature, wash the grafted manganese iron black particles and carbon black particles, and vacuum dry them for use.

[0159] Embodiment A11

[0160] Mixed black electrophoretic particles

[0161] The mixed black electrophoretic particles include 10g of modified first black electrophoretic particles and 5g of modified second black electrophoretic particles, wherein the modified first black electrophoretic particles are modified copper chromium black particles with a density of 1.11kg / L, and the density of the modified first black electrophoretic particles differs by 50% from the density of the dispersion medium of the electrophoretic liquid; the specific surface area is 14m 2 / g; the modified second black electrophoretic particles are modified manganese iron black particles with a density of 3.82kg / L and a specific surface area of ​​15.2m 2 / g.

[0162] Preparation method: Take 10g of manganese iron black raw material and 5g of copper chrome black, add 150mL of toluene solvent, add the mixed solvent and black particles into a flask, then add 75g of methyl methacrylate and a certain amount of silane coupling agent, stir at room temperature for 1h, and the system is a black turbid liquid. Then heat the system to 70℃, slowly add the initiator, and keep the temperature at this temperature for overnight reaction. After the insulation is completed, wait for the system to cool to room temperature, wash the grafted manganese iron black particles and carbon black particles, and vacuum dry them for use.

[0163] Example A12

[0164] Mixed black electrophoretic particles

[0165] The mixed black electrophoretic particles include 10g of modified first black electrophoretic particles and 5g of modified second black electrophoretic particles, wherein the modified first black electrophoretic particles are modified copper chromium black particles with a density of 1.33kg / L, and the density of the modified first black electrophoretic particles differs by 80% from the density of the dispersion medium of the electrophoretic liquid; the specific surface area is 14m 2 / g; the modified second black electrophoretic particles are modified manganese iron black particles with a density of 3.82kg / L and a specific surface area of ​​15.2m 2 / g.

[0166] Preparation method: Take 10g of manganese iron black raw material and 5g of copper chrome black, add 150mL of toluene solvent, add the mixed solvent and black particles into a flask, then add 75g of methyl methacrylate and a certain amount of silane coupling agent, stir at room temperature for 1h, and the system is a black turbid liquid. Then heat the system to 70℃, slowly add the initiator, and keep the temperature at this temperature for overnight reaction. After the insulation is completed, wait for the system to cool to room temperature, wash the grafted manganese iron black particles and carbon black particles, and vacuum dry them for use.

[0167] Embodiment A13

[0168] Synthesis of modified white electrophoretic particles

[0169] Take 10g of titanium dioxide raw material and 100mL of toluene solvent, add the mixed solvent and titanium dioxide into a flask, stir water and silane coupling agent in a beaker for 10 minutes and then add them into the flask, continue to disperse for 30 minutes, then add 50g of methyl methacrylate, stir at room temperature for 1 hour, at this time the system is a white turbid liquid. Then heat the system to 70°C, slowly add the initiator, and keep the reaction at this temperature overnight. After the insulation is completed, wait for the system to cool to room temperature, clean the grafted titanium dioxide particles, and vacuum dry them for use.

[0170] Example B1

[0171] Black and white two-color electrophoresis display liquid and preparation method thereof

[0172] A certain amount of dispersion medium, charge control agent Solsperse 19000 and stabilizer polyisobutylene were added to a ball mill, and then a certain amount of zirconium beads were added; the mixed black electrophoretic particles provided in Example A1 and 6 g of the modified white electrophoretic particles provided in Example A13 were added to the ball mill, ball milled for 16 hours, and the ball milling liquid was separated to obtain a black and white dual system electrophoretic display liquid.

[0173] The electrophoretic display liquid was poured into the liquid crystal box, and a 15V positive and reverse alternating DC voltage was applied. The display effect was observed, and the white reflectivity was 35.62%, the black reflectivity was 1.28%, the contrast was 27.83, the black display time was 583ms, and the white display time was 450ms.

[0174] Example B2

[0175] Black and white two-color electrophoresis display liquid and preparation method thereof

[0176] A certain amount of dispersion medium, charge control agent Solsperse 19000 and stabilizer polyisobutylene were added to a ball mill, and then a certain amount of zirconium beads were added; the mixed black electrophoretic particles provided in Example A2 and 6 g of the modified white electrophoretic particles provided in Example A13 were added to the ball mill, ball milled for 16 hours, and the ball milling liquid was separated to obtain a black and white dual system electrophoretic display liquid.

[0177] The electrophoretic display liquid was poured into the liquid crystal box, and a 15V positive and reverse alternating DC voltage was applied. The display effect was observed, and the white reflectivity was 35.73%, the black reflectivity was 1.56%, the contrast was 22.9, the black display time was 304ms, and the white display time was 464ms.

[0178] Example B3

[0179] Black and white two-color electrophoresis display liquid and preparation method thereof

[0180] A certain amount of dispersion medium, charge control agent Solsperse 19000 and stabilizer polyisobutylene were added to a ball mill, and then a certain amount of zirconium beads were added; the mixed black electrophoretic particles provided in Example A3 and 6 g of the modified white electrophoretic particles provided in Example A13 were added to the ball mill, ball milled for 16 hours, and the ball milling liquid was separated to obtain a black and white dual system electrophoretic display liquid.

[0181] The electrophoretic display liquid was poured into the liquid crystal box, and a 15V positive and reverse alternating DC voltage was applied. The display effect was observed, and the white reflectivity was 35.56%, the black reflectivity was 1.40%, the contrast was 25.40, the black display time was 352ms, and the white display time was 456ms.

[0182] Example B4

[0183] Black and white two-color electrophoresis display liquid and preparation method thereof

[0184] A certain amount of dispersion medium, charge control agent Solsperse 19000 and stabilizer polyisobutylene were added to a ball mill, and then a certain amount of zirconium beads were added; the mixed black electrophoretic particles provided in Example A4 and 6 g of the modified white electrophoretic particles provided in Example A13 were added to the ball mill, ball milled for 16 hours, and the ball milling liquid was separated to obtain a black and white dual system electrophoretic display liquid.

[0185] The electrophoretic display liquid was poured into the liquid crystal box, and a 15V positive and reverse alternating DC voltage was applied. The display effect was observed, and the white reflectivity was 35.21%, the black reflectivity was 1.35%, the contrast was 26.08, the black display time was 383ms, and the white display time was 434ms.

[0186] Example B5

[0187] Black and white two-color electrophoresis display liquid and preparation method thereof

[0188] A certain amount of dispersion medium, charge control agent Solsperse 19000 and stabilizer polyisobutylene were added to a ball mill, and then a certain amount of zirconium beads were added; the mixed black electrophoretic particles provided in Example A5 and 9 g of the modified white electrophoretic particles provided in Example A13 were added to the ball mill, ball milled for 16 hours, and the ball milling liquid was separated to obtain a black and white dual system electrophoretic display liquid.

[0189] The electrophoretic display liquid was poured into the liquid crystal box, and a 15V positive and reverse alternating DC voltage was applied. The display effect was observed, and the white reflectivity was 40.61%, the black reflectivity was 1.40%, the contrast was 30.76, the black display time was 579ms, and the white display time was 265ms.

[0190] Example B6

[0191] Black and white two-color electrophoresis display liquid and preparation method thereof

[0192] A certain amount of dispersion medium, charge control agent Solsperse 19000 and stabilizer polyisobutylene were added to a ball mill, and then a certain amount of zirconium beads were added; the mixed black electrophoretic particles provided in Example A6 and 9 g of the modified white electrophoretic particles provided in Example A13 were added to the ball mill, ball milled for 16 hours, and the ball milling liquid was separated to obtain a black and white dual system electrophoretic display liquid.

[0193] The electrophoretic display liquid was poured into the liquid crystal box, and a 15V positive and reverse alternating DC voltage was applied. The display effect was observed, and the white reflectivity was 40.51%, the black reflectivity was 1.52%, the contrast was 26.65, the black display time was 432ms, and the white display time was 240ms.

[0194] Example B7

[0195] Black and white two-color electrophoresis display liquid and preparation method thereof

[0196] A certain amount of dispersion medium, charge control agent Solsperse 19000 and stabilizer polyisobutylene were added to a ball mill, and then a certain amount of zirconium beads were added; the mixed black electrophoretic particles provided in Example A7 and 8 g of the modified white electrophoretic particles provided in Example A13 were added to the ball mill, ball milled for 16 hours, and the ball milling liquid was separated to obtain a black and white dual system electrophoretic display liquid.

[0197] The electrophoretic display liquid was poured into the liquid crystal box, and a 15V positive and reverse alternating DC voltage was applied. The display effect was observed, and the white reflectivity was 39.83%, the black reflectivity was 1.29%, the contrast was 30.87, the black display time was 638ms, and the white display time was 293ms.

[0198] Example B8

[0199] Black and white two-color electrophoresis display liquid and preparation method thereof

[0200] A certain amount of dispersion medium, charge control agent Solsperse 19000 and stabilizer polyisobutylene were added to a ball mill, and then a certain amount of zirconium beads were added; the mixed black electrophoretic particles provided in Example A8 and 9 g of the modified white electrophoretic particles provided in Example A13 were added to the ball mill, ball milled for 16 hours, and the ball milling liquid was separated to obtain a black and white dual system electrophoretic display liquid.

[0201] The electrophoretic display liquid was poured into the liquid crystal box, and a 15V positive and reverse alternating DC voltage was applied. The display effect was observed, and the white reflectivity was 40.32%, the black reflectivity was 1.40%, the contrast was 29.22, the black display time was 488ms, and the white display time was 268ms.

[0202] Example B9

[0203] Black and white two-color electrophoresis display liquid and preparation method thereof

[0204] A certain amount of dispersion medium, charge control agent Solsperse 19000 and stabilizer polyisobutylene were added to a ball mill, and then a certain amount of zirconium beads were added; 2 g of the mixed black electrophoretic particles provided in Example A9 and 6 g of the modified white electrophoretic particles provided in Example A13 were added to the ball mill, ball milled for 16 hours, and the ball milling liquid was separated to obtain a black and white dual system electrophoretic display liquid.

[0205] The electrophoretic display liquid was poured into the liquid crystal box, and a 15V positive and reverse alternating DC voltage was applied. The display effect was observed, and the white reflectivity was 33.23%, the black reflectivity was 1.23%, the contrast was 27.02, the black display time was 756ms, and the white display time was 537ms.

[0206] Example B10

[0207] Black and white two-color electrophoresis display liquid and preparation method thereof

[0208] A certain amount of dispersion medium, charge control agent Solsperse 19000 and stabilizer polyisobutylene were added to a ball mill, and then a certain amount of zirconium beads were added; 2 g of the mixed black electrophoretic particles provided in Example A10 and 6 g of the modified white electrophoretic particles provided in Example A13 were added to the ball mill, ball milled for 16 hours, and the ball milling liquid was separated to obtain a black and white dual system electrophoretic display liquid.

[0209] The electrophoretic display liquid was poured into the liquid crystal box, and a 15V positive and reverse alternating DC voltage was applied. The display effect was observed, and the white reflectivity was 34.14%, the black reflectivity was 1.34%, the contrast was 25.48, the black display time was 652ms, and the white display time was 499ms.

[0210] Example B11

[0211] Black and white two-color electrophoresis display liquid and preparation method thereof

[0212] A certain amount of dispersion medium, charge control agent Solsperse 19000 and stabilizer polyisobutylene were added to a ball mill, and then a certain amount of zirconium beads were added; 2 g of the mixed black electrophoretic particles provided in Example A11 and 6 g of the modified white electrophoretic particles provided in Example A13 were added to the ball mill, ball milled for 16 hours, and the ball milling liquid was separated to obtain a black and white dual system electrophoretic display liquid.

[0213] The electrophoretic display liquid was poured into the liquid crystal box, and a 15V positive and reverse alternating DC voltage was applied. The display effect was observed, and the white reflectivity was 35.71%, the black reflectivity was 1.37%, the contrast was 26.07, the black display time was 856ms, and the white display time was 503ms.

[0214] Example B10

[0215] Black and white two-color electrophoresis display liquid and preparation method thereof

[0216] A certain amount of dispersion medium, charge control agent Solsperse 19000 and stabilizer polyisobutylene were added to a ball mill, and then a certain amount of zirconium beads were added; 2 g of the mixed black electrophoretic particles provided in Example A12 and 6 g of the modified white electrophoretic particles provided in Example A13 were added to the ball mill, ball milled for 16 hours, and the ball milling liquid was separated to obtain a black and white dual system electrophoretic display liquid.

[0217] The electrophoretic display liquid was poured into the liquid crystal box, and a 15V positive and reverse alternating DC voltage was applied. The display effect was observed, and the white reflectivity was 34.96%, the black reflectivity was 1.32%, the contrast was 26.48, the black display time was 938ms, and the white display time was 550ms.

[0218] Comparative Example 1

[0219] Electrophoresis display liquid and preparation method thereof

[0220] A certain amount of dispersion medium, charge control agent Solsperse19000 and stabilizer polyisobutylene were added to the ball mill, and then a certain amount of zirconium beads were added. 1g of the modified first electrophoretic particles (modified copper chromium black particles) in Example A1 and 7g of the modified titanium dioxide pigment in Example A11 were added to the ball mill, and ball milled for 16 hours. The ball milling liquid was separated to obtain a black and white dual system electrophoretic display liquid. The electrophoretic display liquid was poured into a liquid crystal box, and a 15V positive and negative alternating DC voltage was applied to observe the display effect. The white reflectivity was 34.63%, the black reflectivity was 2.31%, the contrast was 14.99, the black time was 392ms, and the white time was 279ms.

[0221] Comparative Example 2

[0222] Electrophoresis display liquid and preparation method thereof

[0223] A certain amount of dispersion medium, charge control agent Solsperse19000 and stabilizer polyisobutylene were added to the ball mill, and then a certain amount of zirconium beads were added. 1g of the modified second electrophoretic particles (modified manganese iron black particles) in Example A1 and 7g of the modified titanium dioxide pigment in Example A11 were added to the ball mill, and ball milled for 16 hours. The ball milling liquid was separated to obtain a black and white dual system electrophoretic display liquid. The electrophoretic display liquid was poured into a liquid crystal box, and a 15V positive and negative alternating DC voltage was applied to observe the display effect. The white reflectivity was 36.62%, the black reflectivity was 1.25%, the contrast was 29.30, the black time was 1238ms, and the white time was 859ms.

[0224] Comparative Example 3

[0225] Electrophoresis display liquid and preparation method thereof

[0226] A certain amount of dispersion medium, charge control agent Solsperse19000 and stabilizer polyisobutylene were added to the ball mill, and then a certain amount of zirconium beads were added. 1g of the modified second black particles (modified manganese iron black particles) in Example A1 and 0.5g of the modified second black particles (modified copper chromium black particles) in Example A1 and 6g of the modified titanium dioxide pigment in Example A11 were added to the ball mill, ball milled for 16 hours, and the ball milling liquid was separated to obtain a black and white dual system electrophoretic display liquid. The electrophoretic display liquid was poured into a liquid crystal box, and a 15V positive and negative alternating DC voltage was applied to observe the display effect. The white reflectivity was 36.62%, the black reflectivity was 1.34%, the contrast was 27.33, the black time was 916ms, and the white time was 645ms.

[0227] Table 1

[0228] White reflectivity Black reflectivity Contrast Dark time Whitening time Example B1 0.3562 0.0128 27.83 583ms 450ms Example B2 0.3573 0.0156 22.9 304ms 464ms Example B3 0.3556 0.014 25.4 352ms 456ms Example B4 0.3521 0.0135 26.08 383ms 434ms Example B5 0.4061 0.0132 30.76 579ms 265ms Example B6 0.4051 0.0152 26.65 432ms 240ms Example B7 0.3983 0.0129 30.87 638ms 293ms Example B8 0.4032 0.0138 29.22 488ms 268ms Example B9 03323 0.0123 27.02 756ms 537ms Example B10 0.3414 0.0134 25.48 652ms 499ms Example B11 0.3571 0.0137 26.07 856ms 503ms Example B12 0.3496 0.0132 26.48 938ms 550ms Comparative Example 1 0.3463 0.0231 14.99 392ms 279ms Comparative Example 2 0.3662 0.0125 29.3 1238ms 859ms Comparative Example 3 0.3662 0.0134 27.33 916ms 645ms

[0229] According to Table 1, in combination with Examples B1 to B4 and Comparative Example 1, it can be seen that after adding the modified second black particles, the black reflectivity decreases, and the more modified second black particles are added, the lower the reflectivity, and the higher the contrast of the final electrophoretic display, but the more modified second black particles are added, the longer the black display time will be; the specific surface area of ​​the modified second black particles in Examples B5 to B8 is greater than that of the modified second black particles in Examples B1 to B4. By comparing Examples B7 and B1, Examples B6 and B2, Examples B8 and B3, and Examples B5 and B4, it can be seen that their black reflectivity is lower than that in Examples B1 to B4, but due to the larger density of the modified second black particles, their black display time is also longer; by comparing Examples B9 and B1, it can be seen that the larger the density of the modified first black particles, the longer the black display time, and the larger the specific surface area of ​​the modified first black particles, the higher the black reflectivity. Comparative Examples 2 and 3 show that when the content of the modified second black particles is too high, the black display time is long and the display effect is poor.

[0230] In summary, the provided electrophoretic display liquid includes the mixed black electrophoretic particles provided in the embodiment of the present application. Since the mixed black electrophoretic particles include modified first black electrophoretic particles with relatively small density and modified second black electrophoretic particles with relatively large density and large specific surface area, the modified first black electrophoretic particles with relatively small density have a density similar to that of the dispersion medium in the electrophoretic liquid, which can increase the swimming speed of the electrophoretic particles and improve the response speed; further, modified second black electrophoretic particles with relatively large density and large specific surface area are provided for mutual use. Since the modified second black electrophoretic particles have a large specific surface area, the overall black value of the mixed black electrophoretic particles can be increased, and the contrast of the mixed black electrophoretic particles in the electrophoretic system can be increased. The obtained mixed black electrophoretic particles have excellent properties of fast response speed and high contrast. Therefore, the obtained electrophoretic display liquid has excellent performance.

[0231] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A mixed black electrophoretic particle, characterized in that: The mixed black electrophoretic particles include modified first black electrophoretic particles and modified second black electrophoretic particles, the density of the modified first black electrophoretic particles is 0.60-1.38 kg / L, the density of the modified second black electrophoretic particles is 1.40-5.04 kg / L, and the specific surface area of ​​the modified second black electrophoretic particles is greater than 15 m 2 / g.

2. The mixed black electrophoretic particle according to claim 1, characterized in that: The density of the modified first black electrophoretic particles differs from the density of the dispersion medium of the electrophoretic liquid by 0% to 100%.

3. The mixed black electrophoretic particle according to claim 2, characterized in that: The density of the modified first black electrophoretic particles differs from the density of the dispersion medium of the electrophoretic liquid by 0% to 50%.

4. The mixed black electrophoretic particle according to claim 1, characterized in that: The modified first black electrophoretic particles are first black electrophoretic particles with a polymer connected to the surface, and the density of the modified first black electrophoretic particles is 0.60 to 1.38 kg / L; and / or, The modified second black electrophoretic particles are second black electrophoretic particles with a polymer connected to the surface, the density of the modified second black electrophoretic particles is 1.40-5.04 kg / L, and the specific surface area of ​​the modified second black electrophoretic particles is greater than 15 m 2 / g.

5. The mixed black electrophoretic particle according to claim 4, characterized in that: The polymer comprises at least one of polyethylene, polypropylene, polyacrylate, polyurethane, polyester, and polysiloxane; and / or, The first black electrophoretic particles include at least one of copper chrome black, pigment black 32, antimony sulfide, carbon black, manganese iron black, iron oxide black, iron chrome black, and cobalt black; and / or, The second black electrophoretic particles include at least one of copper chrome black, pigment black 32, antimony sulfide, carbon black, manganese iron black, iron oxide black, iron chrome black, and cobalt black.

6. The mixed black electrophoretic particle according to claim 1, characterized in that: The mass ratio of the modified first black electrophoretic particles to the modified second black electrophoretic particles is 1:0.01-1.

7. The mixed black electrophoretic particle according to claim 1, characterized in that: The particle size of the modified first black electrophoretic particles is 180-240 nm; and / or, The particle size of the modified second black electrophoretic particles is 180-240 nm.

8. A method for preparing the mixed black electrophoretic particles according to any one of claims 1 to 7, characterized in that: The steps include: providing at least two types of black electrophoretic particles; The black electrophoretic particles are mixed with a silane coupling agent, a polymer monomer, and a solvent, and are subjected to modification reactions respectively. The polymer is grafted onto the surface of the black electrophoretic particles by the silane coupling agent to obtain a modified first black electrophoretic particle and a modified second black electrophoretic particle, wherein the density of the modified first black electrophoretic particle is 0.60 to 1.38 kg / L, the density of the modified second black electrophoretic particle is 1.40 to 5.04 kg / L, and the specific surface area of ​​the modified second black electrophoretic particle is greater than 15 m 2 / g.

9. The method for preparing mixed black electrophoretic particles according to claim 8, characterized in that: The silane coupling agent is selected from at least one of a silane containing a methacryloxy group and a double bond, and a silane containing an aminoalkyl group and a double bond group; The polymer monomer is at least one selected from the group consisting of lauryl acrylate, lauryl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, hexyl acrylate, hexyl methacrylate, n-octyl acrylate, n-octyl methacrylate, n-octadecyl acrylate, and n-octadecyl methacrylate; The solvent is selected from at least one of ethanol, benzene, toluene and xylene; and / or, The mass ratio of the black electrophoretic particles to the silane coupling agent, the polymer monomer, and the solvent is 1:0.1-0.3:0.8-2:1-8.

10. A black and white two-color electrophoresis display liquid, characterized in that: The total mass of the black and white two-color electrophoresis display liquid is 100%, and the components are as follows in percentage by weight: Electrophoretic particles 10% to 50%, Charge control agent 2% to 15%, Stabilizer 0.1%~1%, Dispersing medium 46%~87.9%; The electrophoretic particles include mixed black electrophoretic particles and modified white electrophoretic particles in a mass ratio of 1:1 to 10, and the mixed black electrophoretic particles are the mixed black electrophoretic particles described in any one of claims 1 to 7 or are prepared by the preparation method of the mixed black electrophoretic particles described in claim 8 or 9.

11. An electrophoretic display device, characterized in that: The electrophoretic display device comprises a substrate and an electrophoretic display layer stacked on any one side of the substrate, wherein the electrophoretic display layer is obtained by coating and drying the black and white two-color electrophoretic display liquid according to claim 10.

Images