Adhesive particles, adhesive, and light-adjustable laminate

Abstract

Provided is an adhesive particle that can suppress the occurrence of dripping during heating, can improve adhesion, and can suppress the occurrence of light leakage. The adhesive particle of the present invention includes a base particle and a coating portion disposed on the surface of the base particle, the base particle being a black particle, and the coating portion including a thermosetting resin.

Description

Technical Field

[0001] This invention relates to adhesive particles. Furthermore, this invention relates to adhesives and dimming laminates using said adhesive particles. Background Technology

[0002] Dimming materials such as dimming glass and dimming films are sometimes used in display devices such as liquid crystal displays and automotive displays. Dimming materials have the property that their light transmittance changes depending on whether an electric field is applied, and are materials that can adjust the amount of incident light.

[0003] Furthermore, liquid crystal display elements are constructed by distributing liquid crystal between two glass or film substrates. In this liquid crystal display element, an adhesive is used to bond the two glass or film substrates together.

[0004] In recent years, with the increasing size and flexibility of display devices, the demand for adhesives with higher adhesion has been rising. Furthermore, to further improve the adhesion of adhesives, adhesive particles are sometimes included. Additionally, to prevent light leakage through these particles in the adhesive, they are sometimes colored dark.

[0005] Patent Document 1 discloses particles comprising a substrate particle and a coating portion disposed on the surface of the substrate particle. In this particle, the substrate particle contains a colorant, and the coating portion is made of a compound having a specific structure. In Patent Document 1, a thermoplastic resin is described as the material of the coating portion.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2018-132740 Summary of the Invention

[0009] The technical problem that the invention aims to solve

[0010] In particles where the surface of the colored substrate particles is coated with thermoplastic resin, the thickness of the coating layer cannot be adequately set, resulting in difficulty in sufficiently improving the adhesion of the particles. Furthermore, when heated, the thermoplastic resin in the coating layer melts and produces droplets, sometimes resulting in reduced adhesion. Additionally, if droplets occur, light from the backlight may sometimes pass through the molten resin when the liquid crystal display element is illuminated (light leakage). Due to light leakage, there are problems such as reduced contrast of the liquid crystal display element or the appearance of white spots, resulting in a decrease in display quality.

[0011] The object of this invention is to provide adhesive particles that can suppress dripping during heating, improve adhesion, and suppress light leakage. Furthermore, the object of this invention is to provide adhesives and dimming laminates using said adhesive particles.

[0012] Technical means to solve technical problems

[0013] According to a broad aspect of the present invention, an adhesive particle is provided having a substrate particle and a coating portion disposed on the surface of the substrate particle, the substrate particle being a black particle, and the coating portion comprising a thermosetting resin.

[0014] In a particular aspect of the adhesive particles of the present invention, the ratio of the thickness of the coating portion to the particle size of the adhesive particles exceeds 0.01.

[0015] In a particular aspect of the adhesive particles of the present invention, the thermosetting resin is an epoxy resin, and the coating portion comprises an amine curing agent.

[0016] In a particular aspect of the adhesive particles of the present invention, the 10% K value of the substrate particles is 10 N / mm. 2 Above and 7000 N / mm 2 the following.

[0017] According to a broad aspect of the invention, an adhesive is provided comprising the aforementioned adhesive particles and adhesive.

[0018] According to a broad aspect of the present invention, a dimming stack is provided, comprising a first substrate, a second substrate, and a dimming layer disposed between the first substrate and the second substrate, wherein the material of the dimming layer comprises the aforementioned adhesive particles.

[0019] Invention Effects

[0020] The adhesive particles of the present invention comprise substrate particles and a coating portion disposed on the surface of the substrate particles. The substrate particles are black particles, and the coating portion comprises a thermosetting resin. In the adhesive particles of the present invention, due to the aforementioned configuration, dripping during heating can be suppressed, adhesion can be improved, and light leakage can be suppressed. Attached Figure Description

[0021] [ Figure 1 ] Figure 1 This is a cross-sectional view showing the adhesive particles of the first embodiment of the present invention.

[0022] [ Figure 2 ] Figure 2 This is a cross-sectional view showing an example of a dimming stack using the adhesive particles of the first embodiment of the present invention in a PDLC manner.

[0023] [ Figure 3 ] Figure 3 This is a cross-sectional view showing an example of a dimming stack using the SPD method of adhesive particles according to the first embodiment of the present invention. Detailed Implementation

[0024] The present invention will now be described in detail.

[0025] <Adhesive particles>

[0026] The adhesive particles of the present invention comprise substrate particles and a coating portion disposed on the surface of the substrate particles. In the adhesive particles of the present invention, the substrate particles are black particles. In the adhesive particles of the present invention, the coating portion comprises a thermosetting resin.

[0027] In the adhesive particles of the present invention, due to the aforementioned configuration, the thickness of the coating portion can be sufficiently ensured, resulting in significantly improved adhesion. Furthermore, the adhesion of adhesives containing the adhesive particles of the present invention can be improved. Bonding can be achieved by heat curing the thermosetting resin. Additionally, dripping during heating can be suppressed. As a result, adhesion can be further improved, and light leakage can be suppressed. Furthermore, contamination caused by dripping can be prevented. By suppressing light leakage, a decrease in the contrast of the liquid crystal display element can be prevented, and a decrease in display quality can be prevented.

[0028] The adhesive particles are suitable for use as adhesives. Furthermore, the adhesive particles can be used in dimming materials, dimming layers, and dimming laminates. The adhesive particles can be used as spacers for dimming glass or as spacers for dimming films. The adhesive particles can be adhesive particles for dimming laminates.

[0029] The shape of the adhesive particles is not particularly limited. The shape of the adhesive particles can be spherical, or other shapes, or flat, etc. It should be noted that spherical is not limited to a perfect sphere, but also includes approximately spherical, such as shapes with an aspect ratio (major axis / minor axis) of 1.5 or less.

[0030] Figure 1 This is a cross-sectional view showing the adhesive particles of the first embodiment of the present invention.

[0031] Figure 1The adhesive particle 1 shown includes a substrate particle 2 and a coating portion 3 disposed on the surface of the substrate particle 2. The coating portion 3 is in contact with the surface of the substrate particle 2 and covers the surface of the substrate particle 2. The adhesive particle 1 is a coated particle in which the surface of the substrate particle 2 is covered by the coating portion 3. In the adhesive particle 1, the substrate particle 2 is a black particle. In the adhesive particle 1, the coating portion 3 contains a thermosetting resin.

[0032] The covering portion may completely cover the surface of the substrate particles, or it may not completely cover the surface of the substrate particles. The substrate particles may have portions that are not covered by the covering portion.

[0033] Because the adhesive particles 1 contain the substrate particles 2, they exhibit excellent gap control. Therefore, the adhesive particles 1 are suitable for use as spacers in dimming stacks, etc. The adhesive particles 1 are suitable for use as spacers for dimming glass and dimming films. For example, in a dimming stack in which the adhesive particles are disposed between substrates, the gap between the substrates can be controlled with high precision, and the uniformity of the thickness between the substrates can be improved. Furthermore, by suppressing the peeling of the conductive film, the dimming performance of the dimming stack can be maintained.

[0034] From a practical point of view, the average particle size of the adhesive particles is preferably 1 μm or more, more preferably 8 μm or more, even more preferably 10 μm or more, preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 25 μm or less.

[0035] When the adhesive particle is perfectly spherical, the particle size refers to its diameter; when the adhesive particle is not perfectly spherical, the particle size refers to its diameter when it is assumed to be a sphere with a volume equivalent to that of the particle.

[0036] Furthermore, the particle size of the adhesive particles refers to the average particle size obtained by measuring the adhesive particles using a particle size measuring device. Examples of such particle size measuring devices include particle size distribution measuring machines that utilize principles such as laser scattering, resistance changes, and image analysis after capture. Specifically, an example of a method for measuring the particle size of the adhesive particles is a method that uses a particle size distribution measuring device (Beckman Coulter's "Multisizer4") to measure approximately 100,000 particle sizes and then measures the average particle size. The average particle size refers to the number-average particle size.

[0037] From the viewpoint of further improving adhesion, the particle size CV value of the adhesive particles is preferably 10% or less, more preferably 7% or less. There is no particular upper limit to the CV value of the particle size of the adhesive particles. The CV value of the particle size of the adhesive particles can be 30% or less.

[0038] The CV value (coefficient of variation) of the particle size of the adhesive particles can be determined as follows.

[0039] CV value (%) = (ρ / Dn) × 100

[0040] ρ: Standard deviation of the particle size of the adhesive particles

[0041] Dn: The average particle size of the adhesive particles

[0042] The compressive modulus (10% K value) of the adhesive particles when compressed by 10% at 25°C is preferably 10 N / mm². 2 The above, more preferably 1000 N / mm 2 The above is preferably 10000 N / mm. 2 Below, 7000 N / mm is more preferred. 2 If the 10%K value is above the lower limit and below the upper limit, the gap can be controlled with high precision.

[0043] The compressive modulus (30% K value) of the adhesive particles when compressed by 30% at 25°C is preferably 50 N / mm². 2 The above, more preferably 2000 N / mm 2 The above is preferably 20000 N / mm. 2 Below, 10000 N / mm is more preferred. 2 If the 30%K value is above the lower limit and below the upper limit, the gap can be controlled with high precision.

[0044] The compressive elastic modulus (10% K value and 30% K value) of the adhesive particles can be determined as follows.

[0045] Using a micro compression testing machine, one adhesive particle is compressed at 25°C, a compression speed of 0.3 mN / s, and a maximum test load of 20 mN on the smooth end face of a cylindrical (100 μm diameter, diamond) indenter. The load value (N) and compression displacement (mm) are measured. The compressive modulus (10% K value and 30% K value) can be calculated from the measured values ​​using the following formula. For example, a FISCHERSCOPE H-100 micro compression testing machine is used. The compressive modulus (10% K value and 30% K value) of the adhesive particle is preferably calculated by arithmetic averaging of the compressive modulus (10% K value and 30% K value) of arbitrarily selected 50 adhesive particles.

[0046] 10% K value and 30% K value (N / mm) 2 ) = (3 / 2 1 / 2)·F·S -3 / 2 ·R -1 / 2

[0047] F: Load value (N) when the cohesive particles are compressed and deformed by 10% or 30%.

[0048] S: Compressive displacement (mm) when the cohesive particles compress by 10% or 30%.

[0049] R: Radius of the adhesive particle (mm)

[0050] The compressive modulus generally and quantitatively represents the hardness of adhesive particles. By using the compressive modulus, the hardness of adhesive particles can be expressed quantitatively and unambiguously.

[0051] From the viewpoint of further improving adhesion, in the following adhesion test A, the tensile yield stress of the adhesive particles is preferably 0.03 MPa or more, more preferably 0.05 MPa or more, and even more preferably 0.10 MPa or more. There is no particular limitation on the upper limit of the tensile yield stress of the adhesive particles. In the following adhesion test A, the tensile yield stress of the adhesive particles may be less than 0.03 MPa or less.

[0052] Furthermore, from the viewpoint of further improving adhesion, in the following adhesion test B, the tensile yield stress of the adhesive particles is preferably 0.05 MPa or more, more preferably 0.07 MPa or more, and even more preferably 0.12 MPa or more. There is no particular limitation on the upper limit of the tensile yield stress of the adhesive particles. In the following adhesion test B, the tensile yield stress of the adhesive particles may be less than 0.05 MPa or less.

[0053] (Adhesion Test A)

[0054] Glass substrates are prepared as the first and second substrates. On the surface of the first substrate, 10 particles / mm are applied. 2 The adhesive particles were dispersed in a manner consistent with JIS K6850. Then, following the method described in JIS K6850, the adhesive particles were dispersed at 5 kgf / cm³. 2 The adhesive particles were bonded to the first and second substrates under pressure and heated at 100°C for 60 minutes to prepare the test specimen. The bond strength of the test specimen at 23°C was measured using a TENSILON universal testing machine at a tensile speed of 20 mm / min and a force sensor rated at 1000 N. This measured value was taken as the tensile yield stress of the adhesive particles.

[0055] (Adhesion Test B)

[0056] Glass substrates are prepared as the first and second substrates. On the surface of the first substrate, 10 particles / mm are applied. 2 The adhesive particles were dispersed in a manner consistent with JIS K6850. Then, following the method described in JIS K6850, the adhesive particles were dispersed at 5 kgf / cm³. 2 The adhesive particles were bonded to the first and second substrates under pressure and heated at 130°C for 60 minutes to prepare the test specimen. The bond strength of the test specimen at 23°C was measured using a TENSILON universal testing machine at a tensile speed of 20 mm / min and a force sensor rated at 1000 N. This measured value was taken as the tensile yield stress of the adhesive particles.

[0057] The glass substrate used is a Matsunami Glass Industry Co., Ltd. "S-7213" or similar. The TE NSILON universal testing machine used is an A&D company "RTI-1310" or similar.

[0058] The following provides further details regarding the adhesive particles. It should be noted that in this specification, "(meth)acrylate" refers to one or both of "acrylate" and "methacrylate," and "(meth)acrylic acid" refers to one or both of "acrylic acid" and "methacrylic acid."

[0059] (Substrate particles)

[0060] The substrate particles are black particles. Because of this configuration, the occurrence of light leakage can be suppressed in the adhesive particles of the present invention.

[0061] The material of the substrate particles is not particularly limited. The material of the substrate particles can be organic or inorganic.

[0062] Examples of such organic materials include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; polycarbonate, polyamide, phenol-formaldehyde resin, melamine-formaldehyde resin, benzoguanamine-formaldehyde resin, urea-formaldehyde resin, phenolic resin, melamine resin, benzoguanamine resin, urea-formaldehyde resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, polyphenylene ether, polyacetal, polyimide, polyamide-imide, polyetheretherketone, polyethersulfone, and divinylbenzene polymers. The divinylbenzene polymer can be a divinylbenzene copolymer. Examples of such divinylbenzene copolymers include divinylbenzene-styrene copolymers and divinylbenzene-(meth)acrylate copolymers. From the viewpoint of easily controlling the hardness of the adhesive particles and the substrate particles within a suitable range, the material of the substrate particles is preferably a polymer formed by polymerizing one or more polymeric monomers having olefinic unsaturated groups.

[0063] When the substrate particles are obtained by polymerizing a polymerizable monomer having an olefinic unsaturated group, examples of polymerizable monomers having an olefinic unsaturated group include non-crosslinked monomers and crosslinked monomers.

[0064] Examples of non-crosslinking monomers include: styrene monomers such as styrene, α-methylstyrene, and chlorostyrene as vinyl compounds; vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, and propyl vinyl ether; vinyl ester compounds such as vinyl acetate, vinyl butyrate, vinyl lauryl ether, and vinyl stearate; halogen-containing monomers such as vinyl chloride and vinyl fluoride; and (meth)acrylate compounds such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, cetyl methacrylate, and propyl methacrylate. Alkyl methacrylate compounds such as stearyl methacrylate, cyclohexyl methacrylate, and isobornyl methacrylate; oxygen-containing methacrylate compounds such as 2-hydroxyethyl methacrylate, glyceryl methacrylate, polyoxyethylene methacrylate, and glycidyl methacrylate; nitrile monomers such as methacrylonitrile; halogenated methacrylate compounds such as trifluoromethyl methacrylate and pentafluoroethyl methacrylate; olefin compounds such as diisobutylene, isobutylene, linear olefins, ethylene, and propylene as α-olefin compounds; and isoprene and butadiene as conjugated diene compounds.

[0065] Examples of crosslinking monomers include: vinyl monomers such as divinylbenzene, 1,4-divinoxybutane, and divinyl sulfone, which are vinyl compounds; and (meth)acrylate compounds such as tetramethylolmethane tetra(meth)acrylate, polytetramethylene glycol diacrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, glycerol tri(meth)acrylate, glycerol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and polypropylene glycol di(meth)acrylate. Multifunctional (meth)acrylate compounds such as polytetramethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, etc.; allyl compounds such as triallyl isocyanurate, triallyl trimellitate, diallyl phthalate, diallyl acrylamide, and diallyl ether; and silane compounds such as tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, isopropyltrimethoxysilane, isobutyltrimethoxysilane, cyclohexyltrimethoxysilane, n-hexyltrimethoxysilane, n-octyltriethoxysilane, and n-decyl Alkoxysilane compounds such as trimethoxysilane, phenyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diisopropyldimethoxysilane, trimethoxysilylstyrene, γ-(meth)acryloyloxypropyltrimethoxysilane, 1,3-divinyltetramethyldisiloxane, methylphenyldimethoxysilane, and diphenyldimethoxysilane; vinyltrimethoxysilane, vinyltriethoxysilane, dimethoxymethylvinylsilane, dimethoxyethylvinylsilane, diethoxymethylvinylsilane, diethoxyethylvinylsilane, ethylmethyldivinylsilane, methylvinyldimethoxysilane, and ethylethyl... Alkoxysilanes containing polymerizable double bonds, such as alkenyl dimethoxysilane, methyl vinyl diethoxysilane, ethyl vinyl diethoxysilane, p-styryl trimethoxysilane, 3-methacryloyloxypropyl methyl dimethoxysilane, 3-methacryloyloxypropyl methyl diethoxysilane, 3-methacryloyloxypropyl methyl diethoxysilane, 3-methacryloyloxypropyl methyl diethoxysilane, 3-acryloyloxypropyl methyl diethoxysilane, etc.; cyclic siloxanes such as decamethylcyclopentasiloxane; modified (reactive) silicone oils such as single-terminal modified silicone oil, two-terminal modified silicone oil, and side-chain type silicone oil; and carboxyl-containing monomers such as (meth)acrylic acid, maleic acid, and maleic anhydride.

[0066] From the viewpoint of improving blackness and suppressing light leakage, the substrate particles preferably contain a colorant. The substrate particles can be obtained by uniformly mixing and dispersing the colorant in a polymerizable monomer having olefinic unsaturated groups and then polymerizing it.

[0067] From the viewpoint of improving blackness and suppressing light leakage, the colorant is preferably a pigment or dye, and more preferably a black pigment or black dye. The colorant can be used alone or in combination of two or more types.

[0068] Examples of pigments include carbon black, titanium black, aniline black, iron oxide, lampblack, graphite, copper-chromium composite oxides, and copper-chromium-zinc composite oxides. From the viewpoint of improving blackness and suppressing light leakage, carbon black is preferred.

[0069] Examples of such dyes include pyrazole azo dyes, aniline azo dyes, triphenylmethane dyes, anthraquinone dyes, anthraquinone dyes, benzylene dyes, oxacyclopentene dyes, pyrazolotriazole azo dyes, pyridone azo dyes, anthocyanin dyes, phenothiazine dyes, pyrrolopyrazole azomethyl dyes, xanthones, phthalocyanine dyes, benzopyran dyes, indigo dyes, pyrrole methylene dyes, triarylmethane dyes, azomethyl dyes, perylene dyes, pyrene dyes, quaterrylene dyes, and quinophthalone dyes. These dyes can be acid dyes, direct dyes, basic dyes, mordant dyes, acid mordant dyes, azo dyes, disperse dyes, oil-soluble dyes, food dyes, and dyes in which two or more of their derivatives are mixed to form black.

[0070] The polymerization method is not particularly limited, and known methods such as free radical polymerization, ionic polymerization, condensation polymerization (condensation polymerization, polycondensation), addition condensation, living polymerization, and living free radical polymerization can be cited as examples. Furthermore, other polymerization methods include suspension polymerization and dispersion polymerization in the presence of a free radical polymerization initiator.

[0071] Examples of such inorganic materials include: silicate glass, borosilicate glass, lead glass, soda-lime glass, alumina and aluminosilicate glass, etc.

[0072] The substrate particles can be formed solely of the organic material, solely of the inorganic material, or both. Preferably, the substrate particles are formed solely of the organic material. In this case, the particles can possess moderate hardness and more effectively function as spacers.

[0073] The substrate particles can be a mixture of organic and inorganic particles. The substrate particles can be core-shell particles. When the substrate particles are a mixture of organic and inorganic particles, examples of inorganic materials used as substrate particles include silica, alumina, barium titanate, zirconium oxide, and polysiloxanes. Preferably, the inorganic material is not a metal. As substrate particles formed from silica, there are no particular limitations; examples include substrate particles obtained by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form cross-linked polymer particles, followed by firing as needed. Examples of organic-inorganic mixed particles include organic-inorganic mixed particles formed from cross-linked alkoxysilyl polymers and acrylic resins.

[0074] The organic-inorganic hybrid particles are preferably core-shell type organic-inorganic hybrid particles having a core and a shell disposed on the surface of the core. Preferably, the core is an organic core. The shell is preferably an inorganic shell. From the viewpoint that the particles more effectively function as spacers, the substrate particles are preferably organic-inorganic hybrid particles having an organic core and an inorganic shell disposed on the surface of the organic core.

[0075] Examples of materials that can be used as the organic core include the aforementioned organic materials.

[0076] Inorganic materials can be used as the material for the inorganic shell, including those that serve as the material for the substrate particles. Silicon dioxide is preferably the material for the inorganic shell. The inorganic shell is preferably formed by calcining a metal alkoxide formed on the surface of the core using a sol-gel method. The metal alkoxide is preferably an alkoxysilane. The inorganic shell is preferably formed from an alkoxysilane.

[0077] From a practical point of view, the particle size of the substrate particles is preferably 0.9 μm or more, more preferably 7.9 μm or more, even more preferably 9.9 μm or more, preferably 49 μm or less, more preferably 29 μm or less, and even more preferably 24.5 μm or less.

[0078] The particle size of the substrate particles refers to the diameter when the substrate particles are perfectly spherical, and to the diameter when the substrate particles are not perfectly spherical, assuming they are spheres with a volume equivalent to that of a perfect sphere.

[0079] Furthermore, the particle size of the substrate particles refers to the average particle size obtained by measuring the substrate particles using a particle size measuring device. Examples of such particle size measuring devices include particle size distribution measuring machines that utilize principles such as laser scattering, resistance changes, and image analysis after capture. Specifically, an example of a method for measuring the particle size of the substrate particles is a method that uses a particle size distribution measuring device (BE CKMAN COULTER's "Multisizer4") to measure approximately 100,000 particles and then measures the average particle size. The average particle size refers to the number-average particle size.

[0080] From the viewpoint of further improving adhesion, the particle size CV value of the substrate particles is preferably 10% or less, more preferably 7% or less. There is no particular upper limit to the particle size CV value of the substrate particles. The particle size CV value of the substrate particles can be 30% or less.

[0081] The CV value (coefficient of variation) of the particle size of the substrate particles can be determined as follows.

[0082] CV value (%) = (ρ / Dn) × 100

[0083] ρ: Standard deviation of the particle size of the substrate particles

[0084] Dn: The average particle size of the substrate particles

[0085] The compressive modulus (10% K value) of the substrate particles when compressed by 10% at 25°C is preferably 10 N / mm². 2 The above, more preferably 1000 N / mm 2 The above is preferably 10000 N / mm. 2 Below, 7000 N / mm is more preferred. 2 If the 10%K value is above the lower limit and below the upper limit, the gap can be controlled with high precision.

[0086] The compressive modulus (30% K value) of the substrate particles when compressed by 30% at 25°C is preferably 50 N / mm². 2 The above, more preferably 2000 N / mm 2 The above is preferably 20000 N / mm. 2 Below, 10000 N / mm is more preferred. 2 If the 30%K value is above the lower limit and below the upper limit, the gap can be controlled with high precision.

[0087] The compressive elastic modulus (10% K value and 30% K value) of the substrate particles can be determined as follows.

[0088] Using a micro compression testing machine, one substrate particle is compressed at 25°C, a compression speed of 0.3 mN / s, and a maximum test load of 20 mN on the smooth end face of a cylindrical (100 μm diameter, diamond) indenter. The load value (N) and compression displacement (mm) are measured. The compressive modulus (10% K value and 30% K value) can be calculated from the measured values ​​using the following formula. For example, a FISCHERSCOPE H-100 micro compression testing machine is used. The compressive modulus (10% K value and 30% K value) of the substrate particle is preferably calculated by arithmetic averaging of the compressive modulus (10% K value and 30% K value) of any arbitrarily selected 50 substrate particles.

[0089] 10% K value and 30% K value (N / mm) 2 ) = (3 / 2 1 / 2 )·F·S -3 / 2 ·R -1 / 2

[0090] F: Load value (N) when the substrate particles undergo 10% or 30% compressive deformation.

[0091] S: Compressive displacement (mm) when the substrate particles undergo 10% or 30% compressive deformation.

[0092] R: Radius of the substrate particles (mm)

[0093] The compressive modulus generally and quantitatively represents the hardness of substrate particles. By using the compressive modulus, the hardness of substrate particles can be expressed quantitatively and unambiguously.

[0094] Of the 100% by weight of adhesive particles, the content of the substrate particles is preferably 13% by weight or more, more preferably 37% by weight or more, even more preferably 63% by weight or more, preferably 99% by weight or less, more preferably 94% by weight or less, and even more preferably 87% by weight or less. If the content of the substrate particles is above the lower limit and below the upper limit, the adhesion can be further improved, and the dripping during heating can be further effectively suppressed.

[0095] From the viewpoint of suppressing light leakage and improving the strength of the substrate particles, the content of the colorant in 100% by weight of the substrate particles is preferably 1% by weight or more, more preferably 3% by weight or more, even more preferably 5% by weight or more, preferably 20% by weight or less, more preferably 15% by weight or less, and even more preferably 10% by weight or less. When the substrate particles contain multiple colorants, the content of the colorant refers to the total content of the multiple colorants.

[0096] (Covering section)

[0097] In the adhesive particles of the present invention, the coating portion is disposed on the surface of the substrate particles. The coating portion comprises a thermosetting resin. The coating portion is a thermosetting resin portion. The thermosetting resin portion is formed of a thermosetting resin and contains a thermosetting resin. In the adhesive particles of the present invention, due to the above-described configuration, the thickness of the coating portion can be sufficiently ensured, resulting in significantly improved adhesion. Furthermore, dripping during heating can be suppressed. As a result, adhesion can be further improved, and light leakage can be suppressed. By suppressing light leakage, a decrease in the contrast of the liquid crystal display element can be prevented, and a decrease in display quality can be prevented.

[0098] The coating may be formed from a single layer. The coating may also be formed from multiple layers. That is, the coating may have a laminated structure of two or more layers. When the coating is formed from multiple layers, the outermost layer preferably comprises a thermosetting resin.

[0099] Examples of thermosetting resins include epoxy resins, vinyl ester resins, and unsaturated polyester resins. One type of thermosetting resin may be used alone, or two or more may be used in combination.

[0100] Examples of epoxy resins include: bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenolic varnish type epoxy resin, biphenyl type epoxy resin, biphenyl varnish type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, fluorene type epoxy resin, phenol aralkyl type epoxy resin, naphthol aralkyl type epoxy resin, dicyclopentadiene type epoxy resin, anthracene type epoxy resin, epoxy resin having an adamantane skeleton, epoxy resin having a tricyclodecane skeleton, and epoxy resin having a triazine core in the skeleton.

[0101] Examples of vinyl ester resins include bis(bis) vinyl ester resins and phenolic varnish vinyl ester resins.

[0102] Examples of unsaturated polyester resins include resins obtained by polycondensation of α,β-unsaturated dicarboxylic acids or their anhydrides with diols.

[0103] From the viewpoint of improving adhesion at low temperatures, the thermosetting resin is preferably an epoxy resin. From the viewpoint of improving adhesion at low temperatures, the thermosetting resin preferably comprises an epoxy resin.

[0104] When using epoxy resin as the material for the adhesive particles, the epoxy resin is preferably a multifunctional epoxy resin. Examples of such multifunctional epoxy resins include 2-functional epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin, 3-functional epoxy resins such as triazine type epoxy resin and glycidylamine type epoxy resin, and 4-functional epoxy resins such as tetraphenol ethane type epoxy resin and glycidylamine type epoxy resin. Only one type of epoxy resin may be used, or two or more types may be used in combination.

[0105] Furthermore, when using epoxy resin as the material for the adhesive particles, it is preferable to use a curing agent together with the epoxy resin. The curing agent heat-cures the epoxy resin. The curing agent is not particularly limited. Examples of curing agents include imidazole curing agents, amine curing agents, phenol curing agents, thiol curing agents such as polythiol curing agents, and acid anhydride curing agents. One type of curing agent may be used alone, or two or more may be used in combination. From the viewpoint of easily controlling the compressibility characteristics of the adhesive particles within a suitable range, an amine curing agent is preferred.

[0106] The imidazole curing agent is not particularly limited. Examples of imidazole curing agents include: 2-methylimidazolium, 2-ethyl-4-methylimidazolium, 1-cyanoethyl-2-phenylimidazolium, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-triazine and 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-triazine isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazolium, Imidazole compounds in which the 5-hydrogen atom of the 1H-imidazolium group is replaced by a hydroxymethyl group, and the 2-hydrogen atom is replaced by a phenyl or tolyl group, such as 2-phenyl-4-methyl-5-hydroxymethylimidazolium, 2-phenyl-4-benzyl-5-hydroxymethylimidazolium, 2-p-tolyl-4-methyl-5-hydroxymethylimidazolium, 2-m-tolyl-4,5-dihydroxymethylimidazolium, and 2-p-tolyl-4,5-dihydroxymethylimidazolium.

[0107] The thiol curing agent is not particularly limited. Examples of thiol curing agents include: trimethylolpropane tri-3-mercaptopropionate, pentaerythritol tetra-3-mercaptopropionate, and dipentaerythritol hexa-3-mercaptopropionate.

[0108] The amine curing agent is not particularly limited. Examples of amine curing agents include: ethylenediamine, hexamethylenediamine, octamethylenediamine, decamethylenediamine, 2,5(2,6)-bis(aminomethyl)bicyclo[2.2.1]heptane, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraspiro[5.5]undecane, bis(4-aminocyclohexyl)methane, phenylenediamine, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, m-phenylenediamine, diaminodiphenylmethane, diaminophenyl ether, m-xylenediamine, diaminonaphthalene, diaminomethylcyclohexane, and diaminodiphenyl sulfone, etc. The preferred amine curing agent is ethylenediamine, hexamethylenediamine, octamethylenediamine, 2,5(2,6)-bis(aminomethyl)bicyclo[2.2.1]heptane, m-phenylenediamine, diaminodiphenylmethane, diaminodiphenyl sulfone, phenylenediamine, or 2,2-bis[4-(4-aminophenoxy)phenyl]propane. Using these preferred amine curing agents improves adhesion at low temperatures. From the viewpoint of improving adhesion at low temperatures, the preferred amine curing agent is ethylenediamine, 2,5(2,6)-bis(aminomethyl)bicyclo[2.2.1]heptane, diaminodiphenylmethane, phenylenediamine, or 2,2-bis[4-(4-aminophenoxy)phenyl]propane.

[0109] The acid anhydride curing agent is not particularly limited; any acid anhydride used as a curing agent for thermosetting compounds such as epoxy compounds can be widely used. Examples of such acid anhydride curing agents include: phthalic anhydride, tetrahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, anhydrides of phthalic acid derivatives, maleic anhydride, nadic anhydride, methylnadic anhydride, glutaric anhydride, succinic anhydride, glycerol bis(triphenyltriglycerid) monoacetate, and ethylene glycol bis(triphenyltriglycerid) anhydride, which are difunctional acid anhydride curing agents; trimellitic anhydride and other trifunctional acid anhydride curing agents; and pyromellitic anhydride, benzophenone tetracarboxylic anhydride, methylcyclohexene tetracarboxylic anhydride, and polyazelaic anhydride, which are quadrufunctional or higher.

[0110] Of the total surface area of ​​the substrate particles, the surface area (coverage rate) covered by the coating portion is preferably 20% or more, more preferably 50% or more, further preferably 80% or more, and particularly preferably 85% or more. There is no particular limitation on the upper limit of the coverage rate. The coverage rate can be 100% or less, or 99% or less. When the coverage rate is above the lower limit, the adhesion can be further improved. Furthermore, when the adhesive particles are used as a gap material, the gap can be controlled with greater precision.

[0111] The surface area (coverage rate) covered by the coating portion out of the total surface area of ​​the substrate particles is determined by observing the adhesive particles with an electron microscope or an optical microscope and calculating the percentage of the surface area covered by the coating portion relative to the projected area of ​​the substrate particles.

[0112] From the viewpoint of further improving adhesion, the thickness of the coating portion is preferably 0.1 μm or more, more preferably 0.5 μm or more, even more preferably 1 μm or more, preferably 10 μm or less, more preferably 7 μm or less, and even more preferably 5 μm or less. It should be noted that when the coating portion is formed of multiple layers, the thickness of the coating portion refers to the overall thickness of the coating portion.

[0113] The thickness of the coating can be calculated by the difference between the particle size of the substrate particles and the particle size of the particles.

[0114] The ratio of the thickness of the coating portion to the particle size of the adhesive particles (thickness of the coating portion / particle size of the adhesive particles) is set as ratio A. From the viewpoint of further improving adhesion and suppressing light leakage, ratio A is preferably greater than 0.01, more preferably 0.02 or more, even more preferably 0.03 or more, particularly preferably 0.05 or more, preferably 0.30 or less, more preferably 0.25 or less, even more preferably 0.20 or less, and particularly preferably 0.15 or less.

[0115] Relative to 100 parts by weight of the substrate particles, the content of the thermosetting resin is preferably 1 part by weight or more, more preferably 6 parts by weight or more, even more preferably 13 parts by weight or more, preferably 87 parts by weight or less, more preferably 63 parts by weight or less, and even more preferably 57 parts by weight or less. If the content of the thermosetting resin is above the lower limit and below the upper limit, the adhesion can be further improved, and dripping during heating can be further effectively suppressed.

[0116] Relative to 100 parts by weight of the substrate particles, the content of the curing agent is preferably 0.1 parts by weight or more, more preferably 1 part by weight or more, even more preferably 2 parts by weight or more, preferably 40 parts by weight or less, more preferably 35 parts by weight or less, even more preferably 30 parts by weight or less. If the content of the curing agent is above the lower limit and below the upper limit, the adhesion at low temperatures can be improved, and agglomeration can be suppressed.

[0117] Relative to 100 parts by weight of the thermosetting resin in the adhesive particles, the content of the curing agent in the adhesive particles is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, even more preferably 15 parts by weight or more, preferably 40 parts by weight or less, more preferably 30 parts by weight or less, and even more preferably 25 parts by weight or less. If the content of the curing agent is above the lower limit and below the upper limit, the adhesion at low temperatures can be improved, and coagulation can be suppressed.

[0118] <Adhesive>

[0119] The adhesive of the present invention comprises the adhesive particles and an adhesive. The adhesive particles are preferably dispersed in the adhesive and used as an adhesive. The adhesive is suitable for use in dimming layers and dimming laminates. One type of adhesive may be used, or two or more types may be used.

[0120] The adhesive is not particularly limited. Insulating resins are typically used as the adhesive. Examples of adhesive resins include vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers, and elastomers. Only one type of adhesive resin may be used, or two or more may be used in combination.

[0121] Examples of vinyl resins include, for example, vinyl acetate resins, acrylic resins, and styrene resins. Examples of thermoplastic resins include, for example, polyolefin resins, ethylene-vinyl acetate copolymers, and polyamide resins. Examples of curable resins include, for example, epoxy resins, polyurethane resins, polyimide resins, and unsaturated polyester resins. It should be noted that the curable resin can be a room-temperature curing resin, a thermosetting resin, a light-curing resin, or a moisture-curing resin. The curable resin can be used in combination with a curing agent. Examples of thermoplastic block copolymers include, for example, styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, hydrides of styrene-butadiene-styrene block copolymers, and hydrides of styrene-isoprene-styrene block copolymers. Examples of elastomers include styrene-butadiene copolymer rubbers and acrylonitrile-styrene block copolymer rubbers.

[0122] The adhesive and the binder preferably contain thermoplastic or thermosetting components. The adhesive and the binder may contain either thermoplastic or thermosetting components.

[0123] In addition to the adhesive particles and the adhesive, the adhesive may also contain various additives such as fillers, extenders, softeners, plasticizers, polymerization catalysts, curing catalysts, colorants, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, lubricants, antistatic agents, and flame retardants.

[0124] Of the 100% by weight of the adhesive, the content of the binder is preferably 10% by weight or more, more preferably 30% by weight or more, even more preferably 50% by weight or more, particularly preferably 70% by weight or more, preferably 99.99% by weight or less, and more preferably 99.9% by weight or less. If the content of the binder is above the lower limit and below the upper limit, the adhesion can be further improved.

[0125] In the adhesive, the content of adhesive particles in 100% by weight is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, preferably 80% by weight or less, more preferably 60% by weight or less, further preferably 40% by weight or less, particularly preferably 20% by weight or less, and most preferably 10% by weight or less. If the content of the adhesive particles is above the lower limit and below the upper limit, the adhesion can be improved, and the gap can be controlled with high precision.

[0126] <Dimming Stack>

[0127] The dimming stack of the present invention includes a first substrate, a second substrate, and a dimming layer disposed between the first substrate and the second substrate. In the dimming stack of the present invention, the material of the dimming layer includes the adhesive particles.

[0128] Figure 2 This is a cross-sectional view showing an example of a dimming stack using the adhesive particles of the first embodiment of the present invention in a PDLC manner.

[0129] The PDLC-based dimming stack 51 includes a first substrate 52, a second substrate 53, and a dimming layer 54. The dimming layer 54 is disposed between the first substrate 52 and the second substrate 53. A sealant may also be disposed around the dimming layer 54 between the first substrate 52 and the second substrate 53.

[0130] The dimming layer 54 includes liquid crystal capsules 54A, an adhesive 54B, and a plurality of adhesive particles 1. The liquid crystal capsules 54A are dispersed in the adhesive 54B. The liquid crystal capsules 54A are held in the adhesive 54B in a capsule-like shape. The liquid crystal material can be dispersed in the adhesive in a capsule-like shape, or the liquid crystal material can be dispersed in the adhesive in the form of a continuous phase.

[0131] The adhesive particles 1 are spherical. In the PDLC dimming laminate 51, the thermosetting resin portion of the adhesive particles 1 is thermosetting.

[0132] Figure 3 This is a cross-sectional view showing an example of a dimming stack using the SPD method of adhesive particles according to the first embodiment of the present invention.

[0133] The SPD-type dimming stack 61 includes a first substrate 62, a second substrate 63, and a dimming layer 64. The dimming layer 64 is disposed between the first substrate 62 and the second substrate 63. A sealant may also be disposed around the dimming layer 64 between the first substrate 62 and the second substrate 63.

[0134] The dimming layer 64 contains a plurality of adhesive particles 1. The adhesive particles 1 are spherical adhesive particles. In the dimming stack 61 of the SPD method, the thermosetting resin portion of the adhesive particles 1 is thermosetting.

[0135] The dimming layer 64 comprises droplets 64A of a dimming suspension and a resin matrix 64B. The droplets 64A of the dimming suspension are dispersed in the resin matrix 64B. The droplets 64A of the dimming suspension are held in the resin matrix 64B in a droplet state.

[0136] Transparent electrodes may also be formed on the surface of the first substrate and the surface of the second substrate. Examples of materials for the transparent electrodes include indium tin oxide (ITO).

[0137] The dimming layer possesses dimming properties. These dimming properties refer to the property that the visible light transmittance changes according to the presence or absence of an applied electric field, thereby adjusting the amount of incident light. Examples of mechanisms that change visible light transmittance include: PDLC (Polymer Dispersed Liquid Crystal), SPD (Suspended Particle Device), guest-host liquid crystal (SUPD) systems using liquid crystals, TN (Twisted Nematic) systems, VA (Vertical Alignment) systems, and IPS (In-Plane-Switching) systems. The material of the dimming layer is not particularly limited; any material can be used as long as it possesses dimming properties.

[0138] The dimming stack is preferably a PDLC dimming stack or an SPD dimming stack.

[0139] [PDLC method]

[0140] The dimming layer preferably further comprises an adhesive and a liquid crystal material dispersed in the adhesive.

[0141] The liquid crystal material is not particularly limited. Preferably, the liquid crystal material has the property of changing orientation when an electric field is applied. The liquid crystal material can be dispersed in the binder as a continuous phase, or it can be dispersed in the binder in the form of liquid crystal drops or liquid crystal capsules. Examples of liquid crystal materials include nematic liquid crystals and cholesteric liquid crystals.

[0142] Examples of materials that can be used for the nematic liquid crystal include cyanobiphenyl derivatives, phenyl esters, azobenzene derivatives, fluorinated biphenyl derivatives, carbonates, and Schiff bases. The nematic liquid crystal may use only one type of material or a combination of two or more types.

[0143] Examples of materials for the cholesteric liquid crystal include: steroid cholesterol derivatives, Schiff bases, azo compounds, oxyazo compounds, benzoic acid esters, biphenyls, terphenyls, cyclohexylcarboxylic acid esters, phenylcyclohexanes, biphenylcyclohexanes, pyrimidines, dioxanes, cyclohexylcyclohexane esters, cyclohexylethanes, cyclohexanes, diphenylacetylene, alkenyl groups, stilbenestes, fused polycyclic liquid crystals, nematic liquid crystals, smectic liquid crystals, and materials obtained by adding chiral components of optically active materials such as Schiff bases, azo compounds, esters, and biphenyls to mixed liquid crystals. The cholesteric liquid crystal material may be a single type or a combination of two or more types.

[0144] The adhesive holds the liquid crystal material in place and inhibits its flow. The adhesive is not particularly limited. Preferably, the adhesive is insoluble in the liquid crystal material, has strength capable of withstanding external forces, and exhibits high transmittance to both reflected and incident light. Examples of materials that can be used as the adhesive include water-soluble polymers such as gelatin, polyvinyl alcohol, cellulose derivatives, polyacrylic acid polymers, ethyleneimine, polyethylene oxide, polyacrylamide, polystyrene sulfonate, polyamidine, and isoprene sulfonate polymers, as well as materials capable of aqueous emulsification such as fluoropolymers, polysiloxane resins, acrylic resins, polyurethane resins, and epoxy resins. The adhesive may use only one type of material or a combination of two or more.

[0145] The adhesive is preferably cross-linked using a cross-linking agent. The cross-linking agent is not particularly limited. Preferably, the cross-linking agent forms cross-links between the adhesives, enabling the adhesive to harden, become insoluble, or become unsoluble. Examples of cross-linking agents include acetaldehyde, glutaraldehyde, glyoxal, potassium alum hydrate (a polyvalent metal salt compound), adipic acid dihydrazide, melamine-formaldehyde oligomer, ethylene glycol diglycidyl ether, polyamide epichlorohydrin, and polycarbodiimide. One cross-linking agent may be used alone, or two or more may be used in combination.

[0146] [SPD method]

[0147] The dimming layer preferably further comprises a resin matrix and a dimming suspension dispersed in the resin matrix.

[0148] The dimming suspension contains a dispersion medium and dimming particles dispersed in the dispersion medium.

[0149] Examples of the dimming particles include: carbon materials such as polyiodides and carbon black; metallic materials such as copper, nickel, iron, cobalt, chromium, titanium, and aluminum; and inorganic compound materials such as silicon nitride, titanium nitride, and alumina. Alternatively, these materials may be particles coated with a polymer. Only one type of dimming particle may be used, or two or more types may be used in combination.

[0150] The dispersion medium disperses the dimming particles in a flowable state. The dispersion medium is preferably a material that selectively adheres to and coats the dimming particles, functions to allow the dimming particles to move into the phase-separated droplet phase upon phase separation from the resin matrix, is non-conductive, and has no affinity for the resin matrix. Furthermore, the dispersion medium is preferably a liquid copolymer with a refractive index similar to that of the resin matrix when the dimming laminate is formed. As the liquid copolymer, (meth)acrylate oligomers having fluorine or hydroxyl groups are preferred, and (meth)acrylate oligomers having both fluorine and hydroxyl groups are more preferred. When using such a copolymer, the fluorine or hydroxyl monomer units face the dimming particles, and the remaining monomer units stabilize the droplets of the dimming suspension within the resin matrix. Therefore, the dimming particles are easily dispersed in the dimming suspension, and upon phase separation from the resin matrix, the dimming particles are easily induced into the phase-separated droplets.

[0151] Examples of (meth)acrylate oligomers having fluorine or hydroxyl groups include: 2,2,2-trifluoroethyl methacrylate / butyl acrylate / 2-hydroxyethyl acrylate copolymer, 3,5,5-trimethylhexyl acrylate / 2-hydroxypropyl acrylate / fumaric acid copolymer, butyl acrylate / 2-hydroxyethyl acrylate copolymer, 2,2,3,3-tetrafluoropropyl acrylate / butyl acrylate / 2-hydroxyethyl acrylate copolymer, 1H,1H,5H-octafluoropentyl acrylate / butyl acrylate / 2-hydroxyethyl acrylate copolymer, 1H,1H,5H-octafluoropentyl acrylate / butyl acrylate / 2-hydroxyethyl acrylate copolymer, 1H,1H,5H-octafluoropentyl acrylate, H,1H,2H,2H-heptafluorodecyl acrylate / butyl acrylate / 2-hydroxyethyl acrylate copolymer, 2,2,2-trifluoroethyl methacrylate / butyl acrylate / 2-hydroxyethyl acrylate copolymer, 2,2,3,3-tetrafluoropropyl methacrylate / butyl acrylate / 2-hydroxyethyl acrylate copolymer, 1H,1H,5H-octafluoropentyl methacrylate / butyl acrylate / 2-hydroxyethyl acrylate copolymer, and 1H,1H,2H,2H-heptafluorodecyl methacrylate / butyl acrylate / 2-hydroxyethyl acrylate copolymer, etc. Furthermore, these (meth)acrylate oligomers more preferably possess both fluorine and hydroxyl groups.

[0152] The weight-average molecular weight of the (meth)acrylate oligomer is preferably 1,000 or more, more preferably 2,000 or more, more preferably 20,000 or less, and even more preferably 10,000 or less.

[0153] The dimming layer can be prepared using a resin material for forming the resin matrix and the dimming suspension.

[0154] The resin material is preferably a resin material that is cured by irradiation with energy rays. Examples of resin materials cured by irradiation with energy rays include polymer compositions comprising a photopolymerization initiator and a polymer compound that is cured by energy rays such as ultraviolet light, visible light, or electron beams. Examples of such polymer compositions include polymeric compositions comprising a polymerizable monomer having an olefinic unsaturated group and a photopolymerization initiator. Examples of such polymerizable monomers having an olefinic unsaturated group include non-crosslinked monomers and crosslinked monomers.

[0155] Examples of non-crosslinking monomers include: styrene monomers such as styrene, α-methylstyrene, and chlorostyrene as vinyl compounds; vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, and propyl vinyl ether; vinyl ester compounds such as vinyl acetate, vinyl butyrate, vinyl lauryl ether, and vinyl stearate; halogen-containing monomers such as vinyl chloride and vinyl fluoride; and (meth)acrylate compounds such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, cetyl methacrylate, and propyl methacrylate. Alkyl methacrylate compounds such as stearyl methacrylate, cyclohexyl methacrylate, and isobornyl methacrylate; oxygen-containing methacrylate compounds such as 2-hydroxyethyl methacrylate, glyceryl methacrylate, polyoxyethylene methacrylate, and glycidyl methacrylate; nitrile monomers such as methacrylonitrile; halogenated methacrylate compounds such as trifluoromethyl methacrylate and pentafluoroethyl methacrylate; olefin compounds such as diisobutylene, isobutylene, linear olefins, ethylene, and propylene as α-olefin compounds; and isoprene and butadiene as conjugated diene compounds.

[0156] Examples of crosslinking monomers include: vinyl monomers such as divinylbenzene, 1,4-divinoxybutane, and divinyl sulfone, which are vinyl compounds; and (meth)acrylate compounds such as tetramethylolmethane tetra(meth)acrylate, polytetramethylene glycol diacrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, glycerol tri(meth)acrylate, glycerol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, and polytetramethylene glycol di(meth)acrylate. Multifunctional (meth)acrylate compounds such as diol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and 1,9-nonanediol di(meth)acrylate; allyl compounds such as triallyl isocyanurate, triallyl trimellitate, diallyl phthalate, diallyl acrylamide, and diallyl ether; and silane compounds such as tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, isopropyltrimethoxysilane, isobutyltrimethoxysilane, and cyclohexyltrimethoxysilane. Alkoxysilane compounds including alkylsilanes, n-hexyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, phenyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diisopropyldimethoxysilane, trimethoxysilylstyrene, γ-(meth)acryloyloxypropyltrimethoxysilane, 1,3-divinyltetramethyldisiloxane, methylphenyldimethoxysilane, diphenyldimethoxysilane, etc.; vinyltrimethoxysilane, vinyltriethoxysilane, dimethoxymethylvinylsilane, dimethoxyethylvinylsilane, diethoxymethylvinylsilane, diethoxyethylvinylsilane, ethylmethyldivinylsilane, methyl... Alkoxysilanes containing polymerizable double bonds, such as vinyl dimethoxysilane, ethyl vinyl dimethoxysilane, methyl vinyl diethoxysilane, ethyl vinyl diethoxysilane, p-styryltrimethoxysilane, 3-methacryloyloxypropylmethyl dimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyl diethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-acryloyloxypropyltrimethoxysilane; cyclic siloxanes such as decamethylcyclopentasiloxane; modified (reactive) silicone oils such as single-terminal modified silicone oil, two-terminal modified silicone oil, and side-chain type silicone oil; and carboxyl-containing monomers such as (meth)acrylic acid, maleic acid, and maleic anhydride.

[0157] Examples of photopolymerization initiators include: 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-(4-(2-hydroxyethoxy)phenyl)-2-hydroxy-2-methyl-1-propane-1-one, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2-hydroxy-2-methyl-1-phenylpropane-1-one, and (1-hydroxycyclohexyl)phenyl one.

[0158] The resin material may include organic solvent-soluble resins, thermoplastic resins, and poly(meth)acrylic acid, etc. Furthermore, the resin material may include various additives such as anti-coloring agents, antioxidants, and adhesion promoters, and may also include solvents.

[0159] (Substrate 1 and Substrate 2)

[0160] The first substrate and the second substrate are preferably light-transmitting substrates. The first substrate and the second substrate are preferably transparent substrates. For example, light is transmitted from one side of the transparent substrate to the other. For example, when viewing a substance located on the other side through the transparent substrate from one side, the substance can be visually identified. Transparency also includes translucency. The transparent substrate can be colorless and transparent or colored and transparent.

[0161] The materials of the first substrate and the second substrate are not particularly limited. The materials of the first substrate and the second substrate may be the same or different. Examples of substrate materials include glass and resin films. Examples of glass include soda-lime glass, lead glass, borosilicate glass, and various other types of glass used in construction, as well as functional glasses such as heat-reflective glass, heat-absorbing glass, and tempered glass. Examples of resin films include polyester films such as polyethylene terephthalate, polyolefin films such as polypropylene, and acrylic resin films. From the perspective of superior transparency, formability, adhesion, and processability, the transparent substrate is preferably a resin substrate, more preferably a resin film, and even more preferably a polyethylene terephthalate film.

[0162] The first substrate and the second substrate preferably have a substrate body and a transparent conductive film formed on the surface of the substrate body, so as to be able to apply an electric field for dimming. Examples of the transparent conductive film include indium tin oxide (ITO), SnO2, and In2O3.

[0163] From the viewpoint of improving the visibility of the dimming stack, the visible light transmittance of the first substrate and the second substrate is preferably 75% or more, and more preferably 80% or more.

[0164] The visible light transmittance of the substrate can be measured by spectrophotometry according to ISO 13837:2008. Alternatively, it can be measured according to methods based on JIS K6714.

[0165] The present invention will now be specifically described with reference to embodiments and comparative examples. The present invention is not limited to the embodiments described below.

[0166] Prepare the following materials.

[0167] Substrate particles:

[0168] Substrate Particle A (black particles, manufactured by Sekisui Chemicals Co., Ltd., "MICROPEARL KBN-512", average particle size 12.0 μm, CV value 4.0%)

[0169] Substrate particles B (black particles, average particle size 13.1 μm, CV value 3.0%, prepared according to synthesis example 1 below)

[0170] Substrate particles C (black particles, manufactured by Sekisui Chemicals Co., Ltd., "MICROPEARL KBN-507", average particle size 7.0 μm, CV value 4.0%)

[0171] Substrate particles D (epoxy resin particles, average particle size 9.8 μm, CV value 7.3%, prepared according to synthesis example 2 below)

[0172] Substrate particles E (white particles, manufactured by Sekisui Chemicals Co., Ltd., "MICROPEARL SP-210", average particle size 10.0 μm, CV value 5.0%)

[0173] (Synthesis example 1)

[0174] After stirring 170g of methyltrimethoxysilane (MTMS) and 35g of water at 25°C for 1 hour, a mixture of 1200g of water and 12g of 1N-ammonia solution was added, and the mixture was stirred for another hour to obtain a dispersion of MTMS seed particles.

[0175] A 1% ammonium dodecyl sulfate aqueous solution (13g) was mixed into a solution obtained by stirring 96g of methyltrimethoxysilane and 467g of water at 25°C for 1 hour. 220g of the dispersion was then added to the resulting mixture, and the mixture was stirred for 20 minutes to prepare an organopolysiloxane dispersion.

[0176] Next, 5g of azobisisobutyronitrile (AIBN) was dissolved in 50g of acrylonitrile to prepare a mixture. This mixture, along with a solution prepared by dissolving 3g of sulfate salt (emulsifier, "NEWCOL707SF" manufactured by Nippon Emulsifier Co., Ltd.) in 100g of deionized water, was stirred at 20,000 rpm for 1 minute using a homogenizer to prepare a monomer emulsion. The monomer emulsion was added to an organopolysiloxane dispersion, stirred for 1 hour, and then kept at 70°C for 6 hours to allow for free radical polymerization of the monomer, thereby preparing a dispersion of composite particles. After cooling, the resulting dispersion was washed with methanol to remove the methanol from the supernatant, and then dried in an oven at 80°C for 1 hour to obtain composite particles. The obtained composite particles were calcined at 580°C for 180 minutes under a nitrogen atmosphere to obtain substrate particles B.

[0177] (Synthesis example 2)

[0178] In a reaction vessel equipped with a thermometer, stirrer, and cooling pipe, 10 parts by weight of bisphenol A epoxy resin (DIC company's "EXA-850-CRP"), 7.5 parts by weight of polyvinylpyrrolidone (dispersion stabilizer), and 250 parts by weight of ethanol were added and stirred at 65°C for 1 hour to ensure uniform dissolution. Next, 2.1 parts by weight of 4,4'-diaminodiphenylmethane (amine curing agent) and 35 parts by weight of ethanol were mixed and dissolved uniformly, then added to the reaction vessel. The mixture was reacted at 65°C for 20 hours to obtain the reaction product. The resulting reaction product was washed with methanol and then fractionated to obtain substrate particles D.

[0179] Thermosetting resins:

[0180] Thermosetting resin F (Bisphenol A type epoxy resin, manufactured by DIC Company, "EXA-850-CRP")

[0181] Thermosetting resin G (Bisphenol A type epoxy resin, manufactured by DIC Company "EXA-4850-150")

[0182] Hardener:

[0183] 2,5(2,6)-bis(aminomethyl)bicyclo[2.2.1]heptane (amine curing agent, manufactured by Mitsui Chemicals Co., Ltd., "NBD A")

[0184] Thermoplastic resin raw materials:

[0185] Styrene monomer

[0186] (Example 1)

[0187] (1) Preparation of adhesive particles

[0188] In a detachable flask, 10 parts by weight of substrate particles A, 2 parts by weight of thermosetting resin F, 2 parts by weight of thermosetting resin G, 25 parts by weight of polyvinylpyrrolidone ("K-30" manufactured by Fujifilm and Koichi Chemical Co., Ltd.), 5 parts by weight of cetyltrimethylammonium bromide, 500 parts by weight of methanol, and 500 parts by weight of ethanol were dissolved by mixing. Next, 2 parts by weight of amine curing agent were added, and the mixture was reacted at 45°C for 20 hours. Then, the mother liquor was separated, washed with methanol, and dried under vacuum at 25°C for 24 hours to obtain adhesive particles.

[0189] (2) Fabrication of dimming stacks using PDLC method

[0190] A PET film with a thickness of 50 μm was prepared as the material for the first and second substrates. An acrylic hard coating resin (LIODURAS TYZ) with dispersed zirconium oxide particles was coated onto one side of the PET film, and then cured by UV irradiation to form a first hard coating with a thickness of 0.8 μm. An acrylic hard coating resin (LIODURAS TYAB) was coated onto the other side of the PET film, and then cured by UV irradiation to form a second hard coating with a thickness of 2.0 μm. Thus, the substrate film was obtained.

[0191] The substrate film was placed inside a vacuum device, and vacuum degassing was performed. The vacuum level reached 9.0 × 10⁻⁶. -4 After Pa, argon gas is introduced, and SiO2 films are sequentially deposited on the surface of the first hard coating from the first hard coating side using DC magnetron sputtering under an argon atmosphere. x Layer, SiO2 layer and SiO x A layer of indium tin oxide (ITO) is stacked on top of the target. Specifically, an ITO sintered target with 7% SnO2 is used, a cathode with a maximum horizontal magnetic flux density of 1000 Gauss on the target surface is used, and the chamber pressure is set to 3.5 × 10⁻⁶. -1 Pa, with the ratio of Ar gas to O2 gas set to 100:1, was introduced into a vacuum device to simultaneously form a conductive layer (indium tin oxide layer) with a thickness of 18 nm. Then, it was annealed at 160°C for 9 minutes using an IR heating oven (manufactured by MINO GROUP), thereby obtaining the first substrate and the second substrate (the substrate of the transparent conductive film). On the surface of the first substrate, at a density of 15 particles / cm²... 2 Disperse adhesive particles. Next, laminate the light-modulating material (prepared according to the method described in "Macromolecules," Vol. 26, pp. 6132-6134 (1993)) onto the second substrate. At this point, at 5 kgf / cm 2 The pressure is heated at 100°C for 60 minutes to bond the adhesive particles to the first and second substrates, thus preparing a dimming laminate.

[0192] (Examples 2-5 and Comparative Examples 2 and 3)

[0193] Except for changing the material of the adhesive particles to that shown in Tables 1 and 2, the adhesive particles and the dimming laminate were prepared in the same manner as in Example 1. It should be noted that in Examples 2-5 and Comparative Example 3, thermosetting resins F and G were used in the same manner as in Example 1.

[0194] (Comparative Example 1)

[0195] In a detachable flask, 10 parts by weight of substrate particles A, 100 parts by weight of methanol, and 900 parts by weight of deionized water containing 1.5% by weight of sodium p-styrene sulfonate were added and allowed to disperse thoroughly. Then, a solution containing 7 parts by weight of styrene monomer and 0.1 parts by weight of ammonium peroxide dissolved in 30 parts by weight of deionized water was added, and the mixture was reacted at 70°C for 10 hours. The mother liquor was then separated, washed with deionized water, and dried under reduced pressure at 55°C for 24 hours, thereby preparing particles without a thermosetting resin portion and with the surface of the substrate particles coated with thermoplastic resin. Except for using the obtained particles, a dimming laminate was prepared in the same manner as in Example 1.

[0196] (Comparative Example 4)

[0197] As adhesive particles, particles (MICROPEARL KBS-507-KA4 manufactured by Sekisui Chemicals Co., Ltd., with an average particle size of 7.16 μm and a CV value of 5.0%) were grafted onto the surface of substrate particles A with thermoplastic resin. Otherwise, a dimming laminate was prepared in the same manner as in Example 1.

[0198] (evaluate)

[0199] (1) Particle size of substrate particles, thickness of coating and particle size of adhesive particles

[0200] The method described above is used to determine the particle size of the substrate particles, the thickness of the coating portion, and the particle size of the adhesive particles. Furthermore, the ratio of the thickness of the coating portion to the particle size of the adhesive particles (thickness of the coating portion / particle size of the adhesive particles) is calculated.

[0201] (2) Droplet inhibition

[0202] A substrate for the transparent conductive film is prepared as a first substrate and a second substrate. On the surface of the first substrate, at a density of 15 particles / cm²... 2The obtained adhesive particles were dispersed in a manner described above. Next, a second substrate was stacked. Then, the substrate was heated at 200°C for 60 minutes, and the presence of droplets on the particle surface was observed using a digital microscope (KEYENCE VHX-2000). The image magnification was set to 200x, and 50 random adhesive particles were observed. Droplet suppression was determined according to the following criteria.

[0203] [Criteria for judging droplet inhibition]

[0204] ○○: The number of adhesive particles in the droplet is less than 3.

[0205] ○: The number of adhesive particles in the droplet is more than 3 but less than 10.

[0206] ×: The number of adhesive particles in the droplet is more than 10.

[0207] (3) Adhesion (tensile yield stress)

[0208] Using the obtained adhesive particles, test specimens (test samples) were prepared according to the adhesiveness test B. The tensile yield stress of the test specimens at 23°C was measured using a TENSILON universal testing machine (A&D "RTI-1310") (Adhesiveness Test B). Adhesion was determined according to the following criteria.

[0209] [Criteria for judging adhesion]

[0210] ○○: Tensile yield stress is above 0.12 MPa

[0211] ○: Tensile yield stress is above 0.07 MPa and less than 0.12 MPa

[0212] ×: Tensile yield stress is less than 0.07 MPa

[0213] (4) Light leakage suppression

[0214] The obtained adhesive particles were used as spacers for TN (twisted nematic) type liquid crystal display elements, and TN type liquid crystal display elements were prepared using the following method.

[0215] After depositing SiO2 films on one side of the first and second substrates (transparent glass plates, 150mm × 150mm) using CVD, an ITO film was formed on the entire surface of the SiO2 film by sputtering. Then, a polyimide alignment film (Nissan Chemical Co., Ltd. "SE-7210") was prepared by spin coating and fired at 280°C for 90 minutes to form the polyimide alignment film. Next, after a rubbing treatment, a dry-spreading machine (NISSHIN ENGINEERING Co., Ltd. "DISPA-μR") was used on the alignment film side of the first substrate at a speed of 1 mm. 2The obtained adhesive particles are dispersed in a pattern of 20 to 100 particles. After forming a peripheral sealant (main agent: SE4500, curing agent: HAVEN CHEMICAL) around the periphery of the second substrate, the first and second substrates are arranged relative to each other with a friction direction (torsion angle) of 90°. After bonding, the sealant is cured at 160°C for 90 minutes to prepare an empty cell. After injecting TN-type liquid crystal (Merck's "MLC-6222") into the obtained empty cell, the injection port is blocked with an adhesive (Sekisui Chemicals Co., Ltd.'s "PHOTOLE C (Fotolac) A-780") to prepare a TN-type liquid crystal display element, which is then heat-treated at 120°C for 30 minutes.

[0216] The obtained TN-type liquid crystal display element was held in a normally white display mode using a polarizing film configured with orthogonal Nicol lenses. While applying a 7V voltage, the light leakage state of the adhesive particles was observed using a digital microscope (KEYENC E "VHX-2000"). The image magnification was set to 200x, and the proportion of adhesive particles with light leakage was calculated in any five fields of view. Light leakage suppression was determined according to the following criteria.

[0217] [Light Leakage Suppression]

[0218] ○○: The amount of light-leaking adhesive particles is less than 3%.

[0219] ○: The amount of light-leaking adhesive particles is more than 3% but less than 7%.

[0220] ×: The amount of adhesive particles causing light leakage is over 7%.

[0221] The composition and results of the adhesive particles are shown in Tables 1 and 2 below.

[0222] [Table 1]

[0223]

[0224] [Table 2]

[0225]

[0226] Symbol Explanation

[0227] 1… Adhesive particles

[0228] 2…substrate particles

[0229] 3… Covering part

[0230] 51…PDLC dimming stack

[0231] 52…1st substrate

[0232] 53...2nd substrate

[0233] 54…Dimming layer

[0234] 54A…Liquid Crystal Capsule

[0235] 54B… Adhesive

[0236] 61…SPD dimming stack

[0237] 62…1st substrate

[0238] 63…2nd substrate

[0239] 64…Dimming layer

[0240] 64A…droplets of dimming suspension

[0241] 64Aa…dispersion medium

[0242] 64Ab…Dimming Particles

[0243] 64B…resin matrix

Claims

1. An adhesive particle, comprising: Substrate particles and a coating portion disposed on the surface of the substrate particles. The substrate particles comprise a polymer formed by polymerizing one or more polymerizable monomers having olefinically unsaturated groups and a colorant. The substrate particles are black particles. The coating portion comprises a thermosetting resin. The thickness of the coating portion is 0.05 or more relative to the particle size of the adhesive particles.

2. The adhesive particle according to claim 1, wherein, The thermosetting resin is epoxy resin. The coating portion contains an amine curing agent.

3. The adhesive particles according to claim 1 or 2, wherein, The 10% K value of the substrate particles is 10 N / mm². 2 Above 7000 N / mm 2 the following, The 10%K value was determined as follows: Using a micro compression testing machine, one substrate particle was compressed at 25°C, a compression speed of 0.3 mN / s, and a maximum test load of 20 mN using a cylindrical smooth indenter with a diameter of 100 μm made of diamond. The load value and compression displacement were measured and calculated using the following formula. The unit of 10%K is N / mm². 2 , 10% K value = (3 / 2) 1 / 2 )·F·S -3 / 2 ·R -1 / 2 F: Load value when the substrate particles undergo 10% compressive deformation, in N. S: Compressive displacement of the substrate particles by 10% of their compressive deformation, in mm. R: Radius of the substrate particles, in mm.

4. An adhesive comprising: The adhesive particles according to any one of claims 1 to 3, and Adhesive.

5. A dimming stack comprising: a first substrate, a second substrate, and a dimming layer disposed between the first substrate and the second substrate. The material of the dimming layer comprises the adhesive particles as described in any one of claims 1 to 3.

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