Colored particles

Abstract

Colored particles according to the present invention are made of a resin material containing an acrylic group and are colored from the center to the surface with a dichromate-based dye.

Description

colored particles

[0001] This disclosure relates to colored particles colored with dyes.

[0002] For example, Patent Document 1 discloses oil-soluble dye-containing polymer particles used in powder inks, toners, paints, powder lubricants, etc. The oil-soluble dye-containing polymer particles of Patent Document 1 are obtained by adding and mixing a polymerizable monomer and an oil-soluble dye as an aqueous dispersion when polymerizing a seed polymer by absorbing a polymerizable monomer.

[0003] Japanese Unexamined Patent Publication No. 63-270538

[0004] Incidentally, one application of fine particles is as a cell spacer (also called a gap filler) for liquid crystal displays. A liquid crystal cell spacer is placed between two glass substrates that make up a liquid crystal panel, and is a component that helps to obtain a clear image by maintaining a uniform thickness of the liquid crystal layer sandwiched between the two glass substrates.

[0005] The applications of microparticles are expanding beyond the aforementioned cell spacers for liquid crystal displays. For example, in recent years, dimmable panels that allow the amount of light taken in to be adjusted with a single switch have begun to attract attention as they contribute to energy conservation and environmental protection. Windows using such dimmable panels are called smart windows, and the smart window market, as well as the dimmable device market that includes them, is expanding.

[0006] The structure of a smart window (also called a dimming device) is similar to that of the liquid crystal panel mentioned earlier, but while a liquid crystal panel uses a glass substrate, a smart window uses a film substrate or a polyethylene terephthalate (PET) substrate. The role of the microparticles in both liquid crystal panels and smart windows is to maintain a uniform thickness of the liquid crystal layer.

[0007] Furthermore, since smart windows are often used outdoors, the microparticles used in smart windows need to be weather-resistant to sunlight. In other words, in addition to having a uniform particle size distribution and high compressive strength, high weather resistance is also required for smart windows.

[0008] However, when the inventors applied a gap agent consisting of existing black microparticles to a dimming device, they found that the microparticles faded after prolonged exposure to sunlight. In other words, while microparticles colored by conventional dyes and coloring methods met the requirements in terms of contrast, background color, and light leakage from the backlight, they were found to have almost no resistance to sunlight.

[0009] Furthermore, in smart windows, the substrate is a film substrate, which is softer than the glass substrate used in LCD panels. Therefore, if the microparticles are hard, like those used for existing glass substrates, there is a risk of damaging the film substrate. As a result, softer microparticles are required compared to existing ones.

[0010] This disclosure is made in view of the above, and its purpose is to provide colored particles that have high weather resistance, are moderately soft, and are resistant to permanent deformation.

[0011] To achieve the above objective, one aspect of this disclosure may provide colored particles colored with a desired color. The colored particles consist of a resin material having an acrylic group and are colored from the center to the surface with a dichromate-based dye.

[0012] The dichromate-based dye may be black. This allows for the production of particles that are colored black from the center to the surface, making them suitable, for example, for use as cell spacers in dimming devices.

[0013] If the particle size of the colored particles is 3 μm or more and 30 μm or less, the strength of the colored particles when compressed by 10% is 2.0 × 10 N / mm². ２ More than 9.8×10N / mm ２ The following is possible:

[0014] Furthermore, if the particle size of the colored particles is 30 μm or more and 100 μm or less, the strength of the colored particles when compressed by 10% is 4.9 N / mm². ２ More than 4.9×10N / mm ２ The following is possible:

[0015] The colored particles described above are not particularly limited, but can be used, for example, as a gap filler for liquid crystals dispersed in liquid crystal injected between two substrates.

[0016] The dichromate-based dye may be present in the resin material in amounts of 2 to 30 parts by weight, 4 to 18 parts by weight, or 12 to 16 parts by weight. This allows the colored particles to be colored to a desired color.

[0017] According to the colored particles of this disclosure, when a resin material having an acrylic group is colored with a dichromate-based dye, it becomes less prone to fading even when exposed to sunlight for a long time, and high weather resistance is obtained. In addition, the colored particles become moderately soft, so when they are placed as spacers between two film substrates, for example, they are less likely to scratch the film substrates. Furthermore, after a compressive force is applied to the colored particles, they easily return to their original shape when that compressive force is removed.

[0018] As described above, the technology relating to this disclosure makes it possible to obtain colored particles that have high weather resistance, are moderately soft, and are resistant to permanent deformation.

[0019] Figure 1 is a cross-sectional view of a liquid crystal panel when colored particles according to an embodiment of the present invention are used as a gap filler for liquid crystals. Figure 2 is a table showing the results of a weather resistance test.

[0020] Embodiments of the present invention will be described in detail below with reference to the drawings. The following description of preferred embodiments is essentially illustrative and is not intended to limit the present invention, its applications, or its uses.

[0021] The colored particles according to the embodiment of the present invention are made of a resin material having an acrylic group and are colored from the center to the surface with a dichromate-based dye. Since the average particle diameter of the colored particles is 100 μm or less, the colored particles of this embodiment can be called fine particles. Furthermore, since the colored particles of this embodiment are spherical, they can be called spherical particles.

[0022] The resin material constituting the colored particles of this embodiment may be any resin material having an acrylic group, and is not particularly limited, but examples include ethylenedi(meth)acrylate, propylenedi(meth)acrylates, butylenedi(meth)acrylates, hexylenedi(meth)acrylates, polyethylene glycol di(meth)acrylates, trimethylolpropanetri(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, and dipentaerythritol. Examples include tall hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, glycerol(meth)acrylate, allyl(meth)acrylate, metaallyl(meth)acrylate, triallyl(meth)acrylate, triallyl(iso)cyanurate, triallyl trimelite, divinylbenzenes, di(meth)allyl phthalates, di(meth)acryloyloxyethyl phthalates, vinylphenyl(meth)allyl ethers, and di(meth)allylcrylamide. The colored particles may be composed of any one of these resin materials, or they may be composed of a mixture of any multiple types.

[0023] The dyes used to color the colored particles are oil-soluble dyes. Dichromate-based dyes are a suitable example of usable oil-soluble dyes. While there are no particular limitations on the colors of dichromate-based dyes, examples include black, navy blue, brown, and green. The color of the dichromate-based dye should be selected according to the intended use of the colored particles.

[0024] The colored particles according to this embodiment are liquid crystal gap agents 4 dispersed in liquid crystal 3 injected between two substrates 1 and 2, as shown in Figure 1 which illustrates a cross-section of the liquid crystal panel 100. In particular, the colored particles can be used as a material for a dimming device (smart window) using a dimming panel (liquid crystal panel 100) that can adjust the amount of light taken in with a single switch operation. In this case, the colored particles are mixed and dispersed as liquid crystal gap agents 4 in the liquid crystal 3 injected between two resin film substrates 1 and 2 that constitute the dimming panel. This maintains a constant distance between the two resin film substrates 1 and 2, allowing the thickness of the liquid crystal 3 to be set to the desired thickness. When used as a liquid crystal gap agent 4, the colored particles are preferably black. By making them black, it is possible to suppress light from passing through due to the colored particles when the operation mode does not transmit light. The dichromate-based dye used to color the colored particles may be a single color or a mixture of multiple colors. When used as a liquid crystal gap agent 4, the colored particles may be colored with a dark color other than black. The resin film substrates 1 and 2 are made of a resin such as PET (polyethylene terephthalate). The dimming device, which includes the gap agent 4 for liquid crystals, can be used, for example, in the windows of buildings, vehicles, aircraft, ships, etc.

[0025] Examples of dichromate-based dyes used as colorants for colored particles include azo dyes, anthraquinone dyes, phthalocyanine dyes, triphenylmethane dyes, azo metal complex dyes, salts of anionic dyes and cationic monomers, and salts of anionic dyes and cationic dyes. The colored particles may be colored with only one of these dyes, or with a mixture of any multiple dyes.

[0026] Furthermore, while usable oil-soluble dyes can be identified by color index numbers, examples include: solvent blue 44, 45, 59, 104; solvent red 24, 68, 89, 124; solvent yellow 13, 14, 33, 79, 93; vat blue 1, 6; vat yellow 6, etc., the colored particles may also be colored with dyes of color index numbers other than those listed above. Among these, azo metal complex dyes and salts of anionic dyes and cationic monomers are preferred.

[0027] Examples of oil-soluble dyes preferably used in this embodiment include, for example, those with color index numbers (CI) of Solvent Blue 35 (solubility in monomethyl methacrylate is 4.2 parts by weight), Solvent Red 132 (solubility in monomethyl methacrylate is 4.3 parts by weight), Solvent Black 27 (solubility in monomethyl methacrylate is 13.0 parts by weight), Solvent Yellow 16 (solubility in monomethyl methacrylate is 4.7 parts by weight), Solvent Blue 70 (solubility in monomethyl methacrylate is 1.6 parts by weight), OIL GREEN 502 (manufactured by Orient Chemical Industry Co., Ltd., solubility in monomethyl methacrylate is 13.2 parts by weight), OIL GREEN BG (manufactured by Orient Chemical Industry Co., Ltd., solubility in monomethyl methacrylate is 1.5 parts by weight), and VALIFAST RED. Examples include 3306 (manufactured by Orient Chemical Industry Co., Ltd., with a solubility of 37.0 parts by weight in monomethyl methacrylate). Of these dyes, only one may be used, or a mixture of any multiple types may be used. Among these, those with a solubility of 4.0 parts by weight or more in monomethyl methacrylate (MMA) are particularly preferred.

[0028] The nickel chromate-based dye is a colorant that uniformly colors the coloring particles from the center to the surface. The intensity of the coloration by the nickel chromate-based dye can be changed according to the use of the coloring particles and the like. The nickel chromate-based dye is contained in the resin material, for example, in an amount of 2 parts by weight or more and 30 parts by weight or less. Thereby, the coloring particles can be surely colored, and particularly when used as a gap agent for liquid crystal, light transmission can be suppressed. The nickel chromate-based dye may be contained in the resin material, for example, in an amount of 4 parts by weight or more and 18 parts by weight or less. Further, the nickel chromate-based dye may be contained in the resin material, for example, in an amount of 12 parts by weight or more and 16 parts by weight or less.

[0029] The average particle diameter of the coloring particles is, for example, 3 μm or more and 30 μm or less. The strength of the coloring particles when the coloring particles in this average particle diameter range are compressed by 10% is 2.0×10 N / mm ２ or more and 9.8×10 N / mm ２ or less.

[0030] Further, the average particle diameter of the coloring particles is not limited to the above-described range, and may be 30 μm or more and 100 μm or less. The strength of the coloring particles when the coloring particles in this average particle diameter range are compressed by 10% is 4.9 N / mm ２ or more and 4.9×10 N / mm ２ or less.

[0031] The average particle diameter (volume average particle diameter) of the coloring particles can be measured, for example, using a Multisizer 3 (manufactured by Beckman Coulter, Inc.). The size of the aperture used for measuring the average particle diameter may be appropriately selected according to the particle diameter to be measured. A specific measurement method is, for example, a method based on JIS Z 8832 "Particle Size Distribution Measurement Method - Electrical Sensing Zone Method". That is, while slowly stirring a beaker filled with ISOTON 2 (manufactured by Beckman Coulter, Inc.: electrolyte for measurement), the slurry of the coloring particles after polymerization is dropped with a dropper, and after adjusting the concentration displayed on the main body screen of the Multisizer 3 to around 10%, the average particle diameter is measured.

[0032] The compressive strength characteristics of the colored particles can be measured, for example, using a micro-compression tester (manufactured by Shimadzu Corporation). The method for measuring the compressive strength characteristics is based on the method specified in JIS Z 8844, "Method for Measuring the Breaking Strength and Deformation Strength of Fine Particles". The diamond indenter used for measuring the compressive strength characteristics may be appropriately selected according to the particle diameter to be measured. Specifically, the colored particles are uniformly sprayed onto the stage, and a load is applied to the colored particles by pressing one indenter against one colored particle at a constant speed to measure the compression characteristics of the colored particle.

[0033] The colored particles according to this embodiment are particles in which a resin material having an acrylic group is colored with a dichromic acid-based dye, so they are less likely to fade even when irradiated with sunlight for a long time. Therefore, even when used as a liquid crystal gap agent for a dimming device over a long period, it is possible to prevent light from leaking through in the non-light-passing operation mode.

[0034] Here, the weather resistance test of the colored particles will be described. For example, the weather resistance test is a test for confirming the fading property of the colored particles. In the weather resistance test, it can be measured with a Dipla Metal Weather (model KW-R5TP-A). The test conditions are set to an irradiance of 81 mW / cm ２ , a temperature of 63°C, and a humidity of 20% (without shower). The method for preparing the test piece is to disperse a plurality of colored particles selected as samples in a highly volatile alcohol or the like, and spray them onto a slide glass using a spray gun. After spraying an appropriate amount, it is dried. Then, the colored particles are sandwiched between another slide glass from above to obtain a test piece. The side surface of this test piece is protected with aluminum tape. The right half of the test piece is covered with aluminum foil so that light does not hit this part. The evaluation method is to confirm fading by visual inspection and an optical microscope at about 144 hours under the above-mentioned weather resistance test conditions. This criterion corresponds to about one year of sunlight irradiation. However, the time required until fading occurs depends on the particle diameter, the amount of colorant encapsulated, and the amount of ultraviolet absorber, so it is not limited to this evaluation criterion.

[0035] Furthermore, we will explain the impact of particle properties, specifically hardness and softness, on subsequent processes. Existing colored particles for LCD panels have higher compressive strength and are harder than these colored particles. When hard, deformation-resistant particles were used on a film substrate that flexes during film deposition, scratches on the film substrate occurred frequently. On the other hand, these colored particles were relatively soft and less likely to scratch the film substrate. Also, because the substrate is a soft film, the particles deformed in accordance with the film's flexing, without impairing optical properties, and without reducing workability or yield. These particle characteristics satisfied the production conditions for subsequent processes, even though film substrates have different production conditions and know-how compared to glass substrates.

[0036] Next, we will explain the PDLC (Polymer Dispersed Liquid Crystal) method, a type of dimming device used in applications such as automotive, marine, building materials, and partitions. A PDLC dimming laminate is constructed by sandwiching a liquid crystal layer, which is a mixture of polymer and liquid crystal, between substrates such as PET films on which transparent electrodes have been deposited. The specific manufacturing method involves uniformly mixing liquid crystal with monomers, oligomers (a combination of a small number of monomers), and a photopolymerization initiator to create a PDLC precursor solution. This mixture is then injected or coated between PET films, for example, on which an ITO film has been deposited, and the film is formed using a roll-to-roll method. During this process, the monomers are polymerized by ultraviolet irradiation or heat to form a polymer. Once the polymerization reaction is complete, the film hardens.

[0037] The resulting film or molded product is then evaluated for its general electro-optic properties. Light transmittance can be measured using, for example, a spectrophotometer. Contrast and haze can be measured when the product is energized and de-energized. Furthermore, in reliability tests, light simulating sunlight can be irradiated using, for example, a xenon lamp, allowing observation of changes in appearance and degradation of properties. The aforementioned film forming methods, constituent materials, and evaluation methods are general methods and are not limited to these.

[0038] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0039] Table 1 shows Examples 1 to 14.

[0040]

[0041]

[0042] Table 2 shows Comparative Examples 1 to 11.

[0043] (Example 1) Oil phase (A) was obtained by dissolving 100 parts by weight of acrylate monomer A, 10 parts by weight of VALIFAST BLACK 3830, and 7 parts by weight of AIBN (initiator) at 40°C. An aqueous solution (B) was obtained by dissolving 5 parts by weight of Gosenol GH-20 in 95 parts by weight of ion-exchanged water. 4.2 parts by weight of OFS-6030 was added to 100 parts by weight of ion-exchanged water and hydrolyzed at 35°C to obtain a seed solution (C) that was adjusted as desired. 300 parts by weight of aqueous solution (B) and 100 parts by weight of oil phase (A) were placed in a container and emulsified by stirring at 17000 rpm for 30 minutes to obtain emulsion (D). Emulsified solution (D) was added to a container containing seed solution (C) and stirred at 45°C. Black colored particles were obtained by polymerization at 80°C for 10 hours. The colored particles obtained in this way have an average particle diameter of 20.0 μm and a strength of 31.5 N / mm when compressed by 10%. ２ That was the case.

[0044] (Example 2) The same procedure as in Example 1 was followed except that the dye in the oil layer (A) prepared in Example 1 was changed to VALIFAST BLACK 3810. The resulting colored particles had an average particle size of 20.1 μm and a strength of 27.2 N / mm when compressed by 10%. ２ That was the case.

[0045] (Example 3) The same procedure as in Example 1 was followed except that the amount of VALIFAST BLACK 3830 added to the dye in the oil layer (A) prepared in Example 1 was changed to 3 parts by weight. The resulting colored particles had an average particle size of 19.8 μm and a strength of 29.0 N / mm when compressed by 10%. ２ That was the case.

[0046] (Example 4) The same procedure as in Example 1 was followed except that the amount of VALIFAST BLACK 3830 added to the dye in the oil layer (A) prepared in Example 1 was changed to 12 parts by weight. The resulting colored particles had an average particle size of 19.9 μm and a strength of 29.0 N / mm when compressed by 10%. ２ That was the case.

[0047] (Example 5) The same procedure as in Example 1 was followed except that the amount of VALIFAST BLACK 3830 added to the dye in the oil layer (A) prepared in Example 1 was changed to 18 parts by weight. The resulting colored particles had an average particle size of 20.4 μm and a strength of 30.6 N / mm when compressed by 10%. ２ That was the case.

[0048] (Example 6) The same procedure as in Example 1 was followed except that the amount of VALIFAST BLACK 3830 added to the dye in the oil layer (A) prepared in Example 1 was changed to 30 parts by weight. The resulting colored particles had an average particle size of 20.2 μm and a strength of 33.7 N / mm when compressed by 10%. ２ That was the case.

[0049] (Example 7) When the same procedure as in Example 1 was performed except that the initiator of the oil layer (A) prepared in Example 1 was changed to Niper BW, the resulting colored particles had an average particle size of 19.2 μm and a strength of 26.9 N / mm when compressed by 10%. ２ That was the case.

[0050] (Example 8) When the same procedure as in Example 1 was performed except that the initiator of the oil layer (A) prepared in Example 1 was changed to V-601, the resulting colored particles had an average particle size of 19.5 μm and a strength of 27.1 N / mm when compressed by 10%. ２ That was the case.

[0051] (Example 9) When the same procedure as in Example 1 was performed except that the initiator of the oil layer (A) prepared in Example 1 was changed to VE-073, the resulting colored particles had an average particle size of 20.3 μm and a strength of 25.2 N / mm when compressed by 10%. ２ That was the case.

[0052] (Example 10) When the same procedure as in Example 1 was performed except that the diameter of the seed solution (C) prepared in Example 1 was adjusted to 2.0 μm, the resulting colored particles had an average particle diameter of 3.1 μm and a strength of 160.6 N / mm when compressed by 10%. ２ That was the case.

[0053] (Example 11) When the same procedure as in Example 1 was performed except that the diameter of the seed solution (C) prepared in Example 1 was adjusted to 8.0 μm, the resulting colored particles had an average particle diameter of 12.0 μm and a strength of 25.7 N / mm when compressed by 10%. ２ That was the case.

[0054] (Example 12) When the same procedure as in Example 1 was performed except that the diameter of the seed solution (C) prepared in Example 1 was adjusted to 19.6 μm, the resulting colored particles had an average particle diameter of 30.4 μm and a strength of 24.7 N / mm when compressed by 10%. ２ That was the case.

[0055] (Example 13) When the same procedure as in Example 1 was performed except that the diameter of the seed solution (C) prepared in Example 1 was adjusted to 34.6 μm, the resulting colored particles had an average particle diameter of 51.6 μm and a strength of 27.8 N / mm when compressed by 10%. ２ That was the case.

[0056] (Example 14) When the same procedure as in Example 1 was performed except that the diameter of the seed solution (C) prepared in Example 1 was adjusted to 68.9 μm, the resulting colored particles had an average particle diameter of 96.2 μm and a strength of 16.1 N / mm when compressed by 10%. ２ That was the case.

[0057] (Comparative Example 1) When the same procedure as in Example 1 was performed except that the dye in the oil layer (A) prepared in Example 1 was changed to VALIFAST BLACK 1821, polymerization inhibition occurred and particle formation was not possible.

[0058] (Comparative Example 2) 3 parts by weight of a mixture of Fujifilm polymerizable dyes RDWR-60, Y-03, and B01, and 1.7 parts by weight of AIBN (initiator) were added to 100 parts by weight of acrylate monomer B and dissolved at 40°C to obtain an oil layer (A). The particles were polymerized using the same procedure as in Example 1, except that the oil layer (A) was changed. The particle strength was very weak and the particle shape could not be maintained.

[0059] (Comparative Example 3) When the same procedure as in Example 1 was performed except that the amount of VALIFAST BLACK 3830 added to the dye in the oil layer (A) prepared in Example 1 was changed to 0.5 parts by weight, the resulting colored particles had an average particle diameter of 20.3 μm and a strength of 29.2 N / mm when compressed by 10%. ２ However, the particles were light in color, resulting in a poor evaluation of their light-blocking properties.

[0060] (Comparative Example 4) When the same procedure as in Example 1 was performed except that the amount of VALIFAST BLACK 3830 added to the dye in the oil layer (A) prepared in Example 1 was changed to 2.0 parts by weight, the resulting colored particles had an average particle size of 20.5 μm and a strength of 25.9 N / mm when compressed by 10%. ２ However, the particles were light in color, resulting in a poor evaluation of their light-blocking properties.

[0061] (Comparative Example 5) When the same procedure as in Example 1 was performed except that the amount of VALIFAST BLACK 3830 added to the dye in the oil layer (A) prepared in Example 1 was changed to 35 parts by weight, the resulting colored particles had an average particle diameter of 20.3 μm and a strength of 35.8 N / mm when compressed by 10%. ２ However, although the particle color was dark, the dye leached out, causing problems with the optical properties.

[0062] (Comparative Example 6) When the dye in the oil layer (A) prepared in Example 1 was changed to VALIFAST BLACK 3810, the initiator was changed to Niper BW, and the amount added was changed to 3 parts by weight, the same procedure as in Example 1 was performed, polymerization inhibition occurred, and particle formation was not possible.

[0063] (Comparative Example 7) When the dye in the oil layer (A) prepared in Example 1 was changed to VALIFAST BLACK 3810, the initiator was changed to perhexyl O, and the amount added was changed to 3 parts by weight, the same procedure as in Example 1 was performed, polymerization inhibition occurred and particle formation was not possible.

[0064] (Comparative Example 8) When the same procedure as in Example 1 was performed except that the diameter of the seed solution (C) prepared in Example 1 was adjusted to 1.7 μm, the resulting colored particles had an average particle diameter of 2.5 μm and a strength of 190.6 N / mm when compressed by 10%. ２ However, the amount of dye incorporated into the particles decreased due to the smaller volume, resulting in a poor evaluation of light-blocking properties.

[0065] (Comparative Example 9) When the same procedure as in Example 1 was performed except that the diameter of the seed solution (C) prepared in Example 1 was adjusted to 80 μm, the resulting colored particles had an average particle diameter of 121 μm and a strength of 17.7 N / mm when compressed by 10%. ２ However, there were many irregularly shaped objects and amorphous objects where particles were bonded together, so from the perspective of production stability, production of particles larger than 100 μm was discontinued.

[0066] (Comparative Example 10) An oil phase (A) was obtained by dissolving 1 part by weight of Niper BW (initiator) in 100 parts by weight of acrylate monomer A at 45°C. An aqueous solution (B) was obtained by dissolving 5 parts by weight of Gosenol GH-20 in 95 parts by weight of ion-exchanged water. 4.2 parts by weight of OFS-6030 was added to 100 parts by weight of ion-exchanged water and hydrolyzed at 35°C to obtain a seed solution (C) of arbitrarily adjusted size of 3.64 μm. 300 parts by weight of aqueous solution (B) and 100 parts by weight of oil phase (A) were placed in a container and emulsified by stirring at 17000 rpm for 30 minutes to obtain an emulsion (D). The emulsion (D) was added to the container containing the seed solution (C) and stirred at 45°C. White particles were obtained by polymerization at 80°C for 10 hours. The surface of the white particles was treated by stirring them in an aqueous solution of a strong acid. After discarding the excess processing solution, the processed particles were dispersed in a solvent of choice, p-phenylenediamine was added, and the resulting colored particles had an average particle size of 6.2 μm and a strength of 74.4 N / mm when compressed by 10%. ２ That was the case.

[0067] (Comparative Example 11) When the same procedure as in Comparative Example 10 was performed except that the diameter of the seed solution (C) prepared in Comparative Example 10 was adjusted to 7.06 μm, the resulting colored particles had an average particle diameter of 12.0 μm and a strength of 56.1 N / mm when compressed by 10%. ２ That was the case.

[0068] (Weather Resistance Test Results) Figure 2 is a table showing the weather resistance test results. In Figure 2, "6 hours of irradiation" refers to the light irradiation time under the weather resistance test conditions described above. In Comparative Example 10, fading occurred in all cases of 6 hours, 12 hours, 24 hours, 48 ​​hours, and 144 hours of irradiation. In Comparative Example 11, fading occurred in 24 hours and 144 hours of irradiation. Note that the fact that fading occurred after 144 hours of irradiation means that fading will occur at shorter irradiation times.

[0069] On the other hand, in Example 11, there was no discoloration after 6 hours of irradiation, but slight discoloration occurred after 24 hours of irradiation. In Example 12, no discoloration occurred after 6 hours, 12 hours, 24 hours, or 48 hours of irradiation, but slight discoloration occurred after 144 hours of irradiation. In Example 13, no discoloration occurred after 24 hours, 48 ​​hours, or 144 hours of irradiation. Thus, it can be seen that the colored particles according to the present invention are less prone to discoloration.

[0070] The embodiments described above are merely illustrative in all respects and should not be interpreted restrictively. Furthermore, any modifications or changes within the equivalent scope of the claims are all within the scope of the present invention. Colored particles may be produced by adding other resin materials as long as the above properties remain unchanged.

[0071] As explained above, the colored particles relating to this disclosure can be used, for example, as a gap filler for liquid crystals.

[0072] 1, 2 Substrate 3 Liquid crystal 4 Liquid crystal gap filler (colored particles) 100 Liquid crystal panel (dimmable panel)

Claims

1. Colored particles containing a resin material having an acrylic group, colored from the center to the surface with a dichromate-based dye.

2. The colored particles according to claim 1, wherein the dichromate-based dye is black.

3. The colored particles according to claim 1, wherein the particle diameter is 3 μm or more and 30 μm or less, and the strength when compressed by 10% is 2.0 × 10 N / mm². ２ More than 9.8×10N / mm ２ The following are the colored particles.

4. The colored particles according to claim 1, wherein the particle diameter is 30 μm or more and 100 μm or less, and the strength when compressed by 10% is 4.9 N / mm². ２ More than 4.9×10N / mm ２ The following are the colored particles.

5. The colored particles according to claim 1, wherein the colored particles are a gap agent for liquid crystals that is dispersed in liquid crystal injected between two substrates.

6. Colored particles according to claim 1, wherein the dichromate-based dye is contained in an amount of 3 parts by weight or more and 30 parts by weight or less relative to the resin material.

7. The colored particles according to claim 6, wherein the dichromate-based dye is contained in an amount of 4 parts by weight or more and 18 parts by weight or less relative to the resin material.

8. The colored particles according to claim 7, wherein the dichromate-based dye is contained in an amount of 12 parts by weight or more and 16 parts by weight or less relative to the resin material.

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