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CN-121975070-A - Method for preparing spherical charged carbon black electrophoretic particles by emulsion polymerization method and application thereof

CN121975070ACN 121975070 ACN121975070 ACN 121975070ACN-121975070-A

Abstract

The invention provides a method for preparing spherical charged carbon black electrophoretic particles by an emulsion polymerization method and application thereof, and belongs to the technical field of electrophoretic display. The invention adopts emulsion polymerization method, carbon black and organic functional monomer are dispersed in water to form stable emulsion under the action of emulsifier, and polymerization reaction is carried out under the action of initiator to obtain regular spherical nano particles, and the charge density of the particle surface is effectively regulated and controlled by polymerizable charge control agent, so that the high contrast and switchable low-power consumption display of the display device are realized. Solves the technical problems of over-thick coating layer, lower surface charge and the like in the existing emulsion polymerization preparation process of the electrophoretic particles.

Inventors

  • LI XIANGGAO
  • MENG ZHU
  • WANG SHIRONG
  • LIU HONGLI

Assignees

  • 天津大学

Dates

Publication Date
20260505
Application Date
20260320

Claims (10)

  1. 1. A method for preparing spherical charged carbon black electrophoretic particles by emulsion polymerization, which is characterized by comprising the following steps: (1) Mixing carbon black with styrene, divinylbenzene, lauryl methacrylate and acrylic acid, and performing sanding treatment to obtain a pre-dispersion liquid of the carbon black; (2) Mixing the pre-dispersion liquid of the carbon black with an emulsifying agent, a charge control agent and water, regulating the pH value to be alkaline, and then homogenizing to obtain a carbon black emulsion; (3) Under the nitrogen atmosphere, adding an initiator into the carbon black emulsion in batches, performing multi-stage heating polymerization reaction, and after the reaction is finished, performing centrifugal washing and drying to obtain the spherical charged carbon black electrophoretic particles; wherein the charge control agent is an anionic charge control agent containing polymerizable double bonds.
  2. 2. The method for preparing spherical charged carbon black electrophoretic particles by emulsion polymerization according to claim 1, wherein in the step (1), the mass ratio of the carbon black to the styrene is 1:5-20, and the mass ratio of the styrene, divinylbenzene, lauryl methacrylate and acrylic acid is 5-20:4:1:1.
  3. 3. The method for preparing spherical charged carbon black electrophoretic particles according to claim 1, wherein in the step (2), the emulsifier is sodium dodecyl sulfonate, the charge controlling agent is sodium p-styrenesulfonate, the homogenizing treatment is carried out at a rotational speed of 3000-6000rpm for 30min, and the pH value is adjusted to 9.0 by saturated sodium bicarbonate solution.
  4. 4. The method for preparing spherical charged carbon black electrophoretic particles according to claim 1, wherein in the step (2), the mass ratio of the carbon black in the pre-dispersion liquid of the carbon black to the emulsifier, charge control agent is 1:1.5:0.15.
  5. 5. The method for preparing spherical charged carbon black electrophoretic particles by emulsion polymerization according to claim 1, wherein in the step (3), the initiator is potassium persulfate, and the multistage polymerization comprises the steps of reacting for 8 hours at 60 ℃ in the first stage, adding divinylbenzene, stirring for 1 hour, adding the initiator, and heating to 70 ℃ for reacting for 12 hours.
  6. 6. The method for preparing spherical charged carbon black electrophoretic particles according to claim 1, wherein in the step (3), the mass ratio of the carbon black emulsion to the initiator is 1000:3-5.
  7. 7. The method for preparing spherical charged carbon black electrophoretic particles by emulsion polymerization according to claim 1, wherein in the step (3), the centrifugal washing process is performed alternately by deionized water, ethanol and ethyl acetate in sequence, the centrifugal parameters are 6000rpm and 8min, and the drying condition is that the drying is performed in a vacuum oven at 100 ℃ for 12 hours.
  8. 8. Spherical charged carbon black electrophoretic particles prepared according to the method of any one of claims 1 to 7, wherein the particle size of the spherical charged carbon black electrophoretic particles is 1 to 2 μm.
  9. 9. Use of the spherical charged carbon black electrophoretic particles of claim 8 for the preparation of an electrophoretic display device.
  10. 10. The use of spherical charged carbon black electrophoretic particles according to claim 9 for preparing an electrophoretic display device, wherein the spherical charged carbon black electrophoretic particles are prepared into an electrophoretic display liquid, and further assembled into the electrophoretic display device.

Description

Method for preparing spherical charged carbon black electrophoretic particles by emulsion polymerization method and application thereof Technical Field The invention belongs to the technical field of electrophoretic display, and particularly relates to a method for preparing spherical charged carbon black electrophoretic particles by an emulsion polymerization method and application thereof. Background The electrophoresis display technology is used as a core support technology of the electronic paper, and is widely applied to the fields of intelligent wearing, electronic tags, flexible display and the like by virtue of the advantages of low power consumption, flexibility, bending property, good visibility in sunlight and the like. With the continuous improvement of the requirements of high resolution, high contrast, low energy consumption and long-term stability of electronic paper display devices in the market, the performance of the electrophoretic particles serving as core functional materials becomes a key factor for restricting the upgrade of the electrophoretic display technology. At present, the electrophoretic particles developed in commercial and laboratory have the problems of uneven particle size distribution, low surface charge quantity, poor stability of a coating layer structure and the like, so that the defects of low response speed, low contrast, high power consumption, particle swelling collapse and the like of a display device are easily caused, and the application requirements of high-end display scenes are difficult to meet. The emulsion polymerization method has the advantages of strong reaction controllability, high operation safety, concentrated particle size distribution of prepared particles, regular shape, adjustable charge quantity and the like, becomes a main flow process for coating and preparing the electrophoretic particles, and is widely applied to research, development and production of the color electrophoretic particles. However, the existing emulsion polymerization technology still has obvious technical shortboards in the preparation of the black electrophoretic particles based on carbon black, and the existing technology adopts conventional polymerization monomers and non-bonding type charge control agents, so that an excessively thick polymer coating layer is easily formed, the particle size of the particles is increased, the color development efficiency of the carbon black is reduced, meanwhile, the non-bonding type charge control agents are weak in binding force with the surfaces of the particles and easy to fall off, the charge quantity on the surfaces of the particles is low, the charge stability is poor, finally, the electrophoretic display devices based on the particles are insufficient in contrast, the driving voltage is higher, the power consumption is difficult to reduce, and the application of the black electrophoretic particles in high-performance-price ratio and high-performance electrophoretic display devices is severely limited. Aiming at the technical pain point of the existing emulsion polymerization method for preparing the carbon black electrophoretic particles, a preparation method which can accurately regulate particle size and sphericity, realize stable bonding of charge control groups and particle surfaces and remarkably improve the charge density of the particle surfaces is developed, and the preparation method becomes an urgent need for promoting the development of the electrophoretic display technology to the high-contrast and low-power consumption directions. Disclosure of Invention Aiming at the technical problems of over-thick coating layer, lower surface charge and the like in the existing emulsion polymerization process for preparing the electrophoretic particles, the invention provides a method for preparing spherical charged carbon black electrophoretic particles by an emulsion polymerization method and application thereof, carbon black and organic functional monomers are dispersed in water to form stable emulsion, and polymerization reaction is carried out under the action of an initiator to obtain regular spherical nano particles, and the charge density of the particle surface is effectively regulated and controlled through a polymerizable charge control agent, so that high contrast and switchable low-power consumption display of the display device are realized. In order to achieve the above purpose, the present invention provides the following technical solutions: The invention provides a method for preparing spherical charged carbon black electrophoretic particles by an emulsion polymerization method, which comprises the following steps: (1) Mixing carbon black with styrene, divinylbenzene, lauryl methacrylate and acrylic acid, and performing sanding treatment to obtain a pre-dispersion liquid of the carbon black; (2) Mixing the pre-dispersion liquid of the carbon black with an emulsifying agent, a charge control agent and water, regu