JP7812209B2 - Particles, their production method and resin composition - Google Patents

Description

The present invention relates to particles, a method for producing the particles, and a resin composition.

Fluorene-based polyester resin microparticles are known, obtained by an esterification reaction between a diol component having a fluorene skeleton and a dicarboxylic acid component (see, for example, Patent Document 1 below). The fluorene-based polyester resin microparticles described in Patent Document 1 have a high refractive index due to the high refractive index of the fluorene skeleton contained in the diol component.

JP 2009-167231 A

Depending on the application and purpose, there is a demand for particles having a fluorene skeleton to be dispersed in a resin. However, the fluorene-based polyester resin particles described in Patent Document 1 have the disadvantage that they dissolve or melt in the resin, making them unable to be dispersed in the resin.

The present invention provides particles that have a high refractive index and excellent dispersibility in resins, a method for producing the same, and a resin composition.

The present invention (1) includes particles containing a crosslinked product of a reaction component containing a bisarylfluorene derivative.

The present invention (2) includes the particles described in (1), in which the reaction components include a first bisarylfluorene derivative having two polymerizable carbon-carbon double bonds or a second bisarylfluorene derivative having two epoxy bonds, and a curing agent.

The present invention (3) includes the particles described in (2), in which the reactive components are only the first bisarylfluorene derivative or the second bisarylfluorene derivative and the curing agent.

The present invention (4) includes the particles described in (2), in which the reaction components contain the first bisarylfluorene derivative and a copolymerizable monomer.

The present invention (5) includes the particles described in (2), in which the reaction components contain the second bisarylfluorene derivative, an epoxy resin, and a curing agent.

The present invention (6) includes particles according to any one of (1) to (5), which contain inorganic particles having a refractive index of 1.7 or greater.

The present invention (7) includes particles described in any one of (1) to (6) that have a substantially spherical shape.

The present invention (8) includes particles described in any one of (1) to (7), which have a median diameter of 1 μm or more.

The present invention (9) includes particles described in any one of (1) to (7), which have a median diameter of less than 1 μm.

The present invention (10) includes a method for producing particles, comprising a first step of dispersing a hydrophobic liquid containing a reaction component containing a bisarylfluorene derivative in water to prepare an aqueous dispersion, and a second step of polymerizing the aqueous dispersion.

The present invention (11) includes the method for producing particles described in (10), in which the reaction component contains a first bisarylfluorene derivative having two polymerizable carbon-carbon double bonds, and in the second step, the aqueous dispersion is polymerized in the presence of a polymerization initiator.

The present invention (12) includes the method for producing particles described in (10), in which the reaction component contains a second bisarylfluorene derivative having two epoxy bonds, and the aqueous dispersion in the second step contains a curing agent.

The present invention (13) includes the method for producing particles described in (12), in which the curing agent contains a hydrophilic first curing agent that can react at low temperatures and a hydrophobic second curing agent that can react at high temperatures, and in the first step, the second curing agent is blended with the hydrophobic liquid, and in the second step, the first curing agent is blended with the aqueous dispersion.

The present invention (14) includes the method for producing particles described in (12), in which the curing agent contains only a hydrophobic third curing agent, and in the first step, the third curing agent is first blended with the hydrophobic liquid, and then the hydrophobic liquid is dispersed in water to prepare an aqueous dispersion.

The present invention (15) includes the method for producing particles described in any one of (10) to (14), in which the first step involves dispersing the hydrophobic liquid further containing an organic solvent in water, and the second step further includes removing the organic solvent.

The present invention (16) includes the method for producing particles described in (11), in which the reaction components contain the first bisarylfluorene derivative and a copolymerizable monomer.

The present invention (17) includes the method for producing particles described in any one of (10) to (16), wherein the hydrophobic liquid further contains inorganic particles having a refractive index of 1.7 or higher.

The present invention (18) includes the method for producing particles described in any one of (10) to (17), wherein in the first step, the median diameter of the hydrophobic liquid is 1 μm or more.

The present invention (19) includes the method for producing particles described in any one of (10) to (17), wherein in the first step, the median diameter of the hydrophobic liquid is less than 1 μm.

The present invention (20) includes a resin composition containing a resin and particles described in any one of (1) to (9).

The particles obtained by the manufacturing method of the present invention have a high refractive index and excellent dispersibility in resins.

The resin composition of the present invention has a high refractive index, excellent particle dispersibility in the resin, and excellent optical properties, particularly light diffusion.

FIG. 1 is an image-processed SEM photograph of the particles of Comparative Example 5 melt-kneaded in an acrylic resin. FIG. 2 is an image-processed SEM photograph of the particles of Comparative Example 1 melt-kneaded in an acrylic resin.

[particle]
The particles of the present invention comprise crosslinked reactive components.

The reaction components contain a bisarylfluorene derivative. Specifically, the reaction components contain a first bisarylfluorene derivative or a second bisarylfluorene derivative and a curing agent.

Examples of the aryl group in the first bisarylfluorene derivative include bisphenyl and bisnaphthyl. Preferably, bisphenyl is used.

The first bisarylfluorene derivative has two polymerizable carbon-carbon double bonds. The polymerizable carbon-carbon double bond is, for example, a vinyl group. Examples of groups containing a polymerizable carbon-carbon double bond include a (meth)acryloyl group. The (meth)acryloyl group includes a methacryloyl group and/or an acryloyl group. The definition of (meth) below is the same as above. The (meth)acryloyl group is linked to the aryl group, for example, via an oxyalkylene group. The oxyalkylene group includes monooxyalkylene and polyoxyalkylene. Examples of oxyalkylene groups include oxyethylene and oxypropylene, with oxyethylene being preferred. The (meth)acryloyl group may be directly linked to the aryl group.

First bisarylfluorene derivatives are described in JP-A-4-325508, JP-A-2009-173648, WO 2013/022065, JP-A-2015-199952, and JP-A-2017-186513. First bisarylfluorene derivatives can be used alone or in combination.

Examples of the first bisarylfluorene derivative include BPEF-A represented by the following formula (1), BPEF-9EOA represented by the following formula (2), BNEF-A represented by the following formula (3), and BPEF-9EOGA represented by the following formula (4).

BPEF-A represented by formula (1) is 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene.

BPEF-9EOA, represented by formula (2), is an ester of acrylic acid and a compound (BPEF-9EO) in which an average of 9 moles of ethylene oxide are added to 1 mole of 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene. Note that BPEF-9EO may be a mixture containing a compound with 9 moles of ethylene oxide added as the main component, and containing compounds with 5 to 8 moles of ethylene oxide added, and compounds with 9 to 12 moles of ethylene oxide added as secondary components. The median number of ethylene oxide added in BPEF-9EO is 9 moles. Hereinafter, the number of ethylene oxide added can be defined as above.

BNEF-A, represented by formula (3), is 9,9-bis[6-(2-acryloyloxyethoxy)-2-naphthyl]fluorene.

BPEF-9EOGA, represented by formula (4), is a diacrylate of a compound (BPEF-9EOG) in which an average of 9 moles of ethylene oxide are added to 1 mole of 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene.

The proportion of the first bisarylfluorene derivative in the reaction components is, for example, 25% by mass or more, preferably 40% by mass or more, and, for example, 100% by mass or less.

Examples of the aryl group in the second bisarylfluorene derivative include bisphenyl and bisnaphthyl. Preferably, bisnaphthyl is used.

The second bisarylfluorene derivative has two epoxy bonds. The epoxy bonds are contained in, for example, a glycidyl ether group. The glycidyl ether group is, for example, directly bonded to an aryl group. The glycidyl ether group may also be linked to the aryl group via an oxyalkylene group exemplified for the first bisarylfluorene derivative.

Second bisarylfluorene derivatives are described in JP 2012-102228 A and JP 2009-155256 A. Second bisarylfluorene derivatives can be used alone or in combination.

Examples of the second bisarylfluorene derivative include BNFG represented by the following formula (5), BPEFG represented by the following formula (6), and BPFG represented by the following formula (7).

BNFG represented by formula (5) is 9,9-bis(6-glycidyloxy-2-naphthyl)fluorene.

BPEFG, represented by formula (6), is 9,9-bis[4-(2-glycidyloxyethoxy)phenyl]fluorene.

BPFG represented by formula (7) is 9,9-bis(4-glycidyloxyphenyl)fluorene.

The proportion of the second bisarylfluorene derivative in the reaction components is, for example, 25% by mass or more, preferably 40% by mass or more, and, for example, 99.9% by mass or less.

The curing agent may be, for example, an epoxy resin curing agent. Examples of curing agents include active hydrogen group-containing compounds. Examples of active hydrogen group-containing compounds include imidazole compounds, polyamine compounds (including polyamidoamine), dicyandiamide, polymercaptan compounds, and novolac phenolic resins. Other examples of curing agents include acid anhydride compounds. Examples of acid anhydride compounds include phthalic anhydride. Preferred curing agents include imidazole compounds and polyamine compounds. If the curing agent is a polyamidoamine or novolac phenolic resin, the high molecular weight of the polyamidoamine or novolac phenolic resin results in a low amount of reactive groups (active hydrogen groups) per molecule involved in curing. Therefore, the proportion of the curing agent increases, and the proportion of the second bisarylfluorene derivative decreases. This can make it difficult to achieve a high refractive index, which may be undesirable. A more preferred curing agent is a combination of a hydrophilic polyamine compound and a hydrophobic imidazole compound, from the viewpoint of ensuring the first curing of the hydrophobic liquid in the aqueous phase. Furthermore, imidazole compounds are preferable to polyamine compounds. The reason for this is as follows: curing with imidazole compounds proceeds with smaller addition amounts than with polyamine compounds, because they react as an ionic polymerization initiator. Therefore, the blending ratio of imidazole can be lower than that of polyamine compounds, making it more suitable for use.

Examples of imidazole compounds include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole (2E4MZ), 2-phenylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-phenylimidazole. A preferred imidazole compound is 2E4MZ. Furthermore, the imidazole compound is preferably hydrophobic. The molecular weight of the imidazole compound is, for example, 250 or less, preferably 200 or less.

Examples of polyamine compounds include linear aliphatic polyamine compounds, cyclic aliphatic polyamine compounds, araliphatic polyamines, and aromatic polyamine compounds. Examples of linear aliphatic polyamine compounds include ethylenediamine, diethylenetriamine (DETA), triethylenetetramine, and tetraethylenepentamine. Examples of cyclic aliphatic polyamine compounds include isophorone diamine. Examples of araliphatic polyamine compounds include xylylenediamine. Examples of xylylenediamines include 1,2-xylylenediamine, 1,3-xylylenediamine, and 1,4-xylylenediamine. Xylylenediamines are preferably 1,3-xylylenediamine. Aromatic polyamine compounds include xylylenediamine and diaminodiphenylmethane. Examples of polyamine compounds are preferably linear aliphatic polyamine compounds and araliphatic polyamine compounds. Examples of linear aliphatic polyamine compounds are preferably DETA. Furthermore, a preferred example of the polyamine compound is 1,3-xylylenediamine. The molecular weight of the polyamine compound is, for example, 160 or less, preferably 140 or less.

The curing agent can be used alone or in combination. A preferred curing agent is a combination of a low-temperature curing agent (first curing agent) that can react at temperatures below 100°C and a high-temperature curing agent (second curing agent) that can react at temperatures above 100°C.

Examples of low-temperature curing agents include chain aliphatic polyamine compounds and cyclic aliphatic polyamine compounds, preferably chain aliphatic polyamine compounds, and more preferably DETA. Low-temperature curing agents may be, for example, either hydrophilic or hydrophobic.

Examples of high-temperature curing agents include imidazole compounds and aromatic polyamine compounds, preferably imidazole compounds, and more preferably 2E4MZ. High-temperature curing agents may be, for example, either hydrophilic or hydrophobic. High-temperature curing agents are preferably hydrophobic.

If the low-temperature curing agent, which is an example of a first curing agent, is hydrophilic and the high-temperature curing agent, which is an example of a second curing agent, is hydrophobic, i.e., if the curing agent contains both a first curing agent and a second curing agent, the second bisarylfluorene derivative reacts with the low-temperature curing agent on the surface of the droplets of hydrophobic liquid (described below) in the aqueous dispersion (first curing) to form a crosslinked shell and form particles. These particles can then be reacted at a high temperature above 100°C (secondary curing or post-curing) to form a crosslinked core. In this case, the shell contains a crosslinked product of the low-temperature curing agent (first curing agent), and the core contains a crosslinked product of the high-temperature curing agent (second curing agent).

As a curing agent, preferably, a polyamine (third curing agent) having high affinity with the second bisarylfluorene derivative is used alone, and more preferably, an araliphatic polyamine is used alone. Note that araliphatic polyamines are low-temperature curing agents.

If the curing agent contains only the third curing agent described above, it will have affinity for the hydrophobic liquid containing the second bisarylfluorene derivative and can be distributed throughout the hydrophobic liquid, allowing the entire particle to be cured at once. This allows the formation of uniformly crosslinked particles.

The number of parts by mass of the curing agent per 100 parts by mass of the second bisarylfluorene derivative is, for example, 1 part by mass or more, preferably 3 parts by mass or more, and for example, 40 parts by mass or less, preferably 20 parts by mass or less.

When the curing agent is a combination of a low-temperature curing agent (first curing agent) and a high-temperature curing agent (second curing agent), the number of parts by mass of the high-temperature curing agent per 100 parts by mass of the low-temperature curing agent is, for example, 25 parts by mass or more, preferably 75 parts by mass or more, and, for example, 200 parts by mass or less, preferably 125 parts by mass or less.

The number of parts by mass of the high-temperature curing curing agent (second curing agent) per 100 parts by mass of the second bisarylfluorene derivative is, for example, 0.5 parts by mass or more, preferably 1 part by mass or more, and for example, 25 parts by mass or less, preferably 10 parts by mass or less.

The number of parts by mass of the low-temperature curing agent (first curing agent) per 100 parts by mass of the second bisarylfluorene derivative is, for example, 0.5 parts by mass or more, preferably 1 part by mass or more, and for example, 25 parts by mass or less, preferably 10 parts by mass or less.

The present invention includes embodiments in which the reaction components are only the first bisarylfluorene derivative, and embodiments in which the reaction components are only the second bisarylfluorene derivative and a curing agent. When the reaction components are only the first bisarylfluorene derivative, the proportion of the first bisarylfluorene derivative in the reaction components is 100% by mass. When the reaction components are only the second bisarylfluorene derivative and a curing agent, the proportion of the total amount of the second bisarylfluorene derivative and the curing agent in the reaction components is 100% by mass.

The crosslinked body is, for example, a cured body. Therefore, particles containing the crosslinked body do not substantially melt when heated. Furthermore, the crosslinked body does not dissolve in either organic solvents or resins (described below). Therefore, the particles have excellent dispersibility in resins.

The present invention also includes an embodiment in which, when the reaction components include a first bisarylfluorene derivative, they further include a copolymerizable monomer. In this embodiment, the reaction components include the first bisarylfluorene derivative and a copolymerizable monomer. Preferably, the reaction components consist of the first bisarylfluorene derivative and a copolymerizable monomer.

Examples of the copolymerizable monomer include vinyl monomers that are copolymerizable with the first bisarylfluorene derivative. Also, examples of the copolymerizable monomer include vinyl monomers that dissolve the first bisarylfluorene derivative.

Vinyl monomers are liquid at, for example, 25°C. Vinyl monomers have low viscosity. Specifically, the viscosity of vinyl monomers at 25°C is, for example, 100 mPa·s or less, preferably 10 mPa·s or less, more preferably 1 mPa·s or less, and, for example, 0.1 mPa·s or more. The viscosity of vinyl monomers is determined in accordance with JIS K6727-2 (2012).

Examples of vinyl monomers include monofunctional vinyl monomers having one polymerizable carbon-carbon double bond and polyfunctional vinyl monomers having two or more polymerizable carbon-carbon double bonds. However, none of the above vinyl monomers have a bisarylfluorene skeleton.

Examples of monofunctional vinyl monomers include aromatic vinyl monomers, (meth)acrylic acid ester monomers, nitrile monomers, vinyl ester monomers, maleic acid ester monomers, and vinyl halides. Preferred examples of monofunctional vinyl monomers include aromatic vinyl monomers. Examples of aromatic vinyl monomers include styrene, p-methylstyrene, o-methylstyrene, and α-methylstyrene. Preferred examples of aromatic vinyl monomers include styrene. Examples of (meth)acrylic acid ester monomers include methyl (meth)acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate. Examples of nitrile monomers include acrylonitrile and methacrylonitrile. Examples of vinyl ester monomers include vinyl acetate and vinyl propionate. Examples of maleic acid ester monomers include dimethyl maleate, diethyl maleate, and dibutyl maleate. Examples of vinyl halides include vinyl chloride and vinyl fluoride. Monofunctional vinyl monomers can be used alone or in combination. Preferred examples of monofunctional vinyl monomers include aromatic vinyl monomers.

The polyfunctional vinyl monomer preferably has only two polymerizable carbon-carbon double bonds. Examples of polyfunctional vinyl monomers include bifunctional aromatic vinyl monomers and alkylene glycol di(meth)acrylates. Examples of bifunctional aromatic vinyl monomers include divinylbenzene. Examples of alkylene glycol di(meth)acrylates include ethylene glycol di(meth)acrylate and butylene glycol di(meth)acrylate.

The number of parts by mass of the copolymerizable monomer per 100 parts by mass of the first bisarylfluorene derivative is, for example, 10 parts by mass or more, preferably 50 parts by mass or more, more preferably 75 parts by mass or more, and for example, 200 parts by mass or less, preferably 150 parts by mass or less, more preferably 125 parts by mass or less. The ratio of the number of moles of carbon-carbon double bonds in the copolymerizable monomer to the number of moles of carbon-carbon double bonds in the first bisarylfluorene derivative is, for example, 0.1 or more, preferably 0.2 or more, and for example, 4.0 or less, preferably 3.0 or less.

The present invention also includes an embodiment in which, when the reaction components include a second bisarylfluorene derivative, the reaction components further include an epoxy resin. In this embodiment, the reaction components include a second bisarylfluorene derivative and an epoxy resin.

The epoxy resin has, for example, two epoxy bonds but does not have a bisarylfluorene skeleton. Examples of epoxy resins include bisphenol A epoxy resin, bisphenol F epoxy resin, phenol novolac epoxy resin, and cresol novolac epoxy resin. By including the above-mentioned epoxy resins as reaction components, the epoxy resin is copolymerized with the second bisarylfluorene derivative, making it possible to adjust the refractive index and potentially reducing the amount of solvent in the hydrophobic liquid.

The epoxy equivalent of the epoxy resin is, for example, 100 g/eq or more and 1,000 g/eq or less. The state of the epoxy resin at 20°C is, for example, liquid.

The number of parts by mass of epoxy resin per 100 parts by mass of the second bisarylfluorene derivative is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, and for example, 50 parts by mass or less, preferably 40 parts by mass or less.

The particles may further include inorganic particles. In this case, the particles include a crosslinked body and inorganic particles.

The inorganic particles are, for example, dispersed in the crosslinked material.

The refractive index of the inorganic particles is, for example, 1.7 or more, preferably 1.75 or more, more preferably 1.8 or more, and is, for example, 2.0 or less. If the refractive index of the inorganic particles is equal to or greater than the above-mentioned lower limit, the refractive index of the particles can be increased.

Examples of inorganic particles include zirconium oxide (zirconia) particles and titanium oxide (titania) particles. Zirconia particles are preferred as inorganic particles.

The particle diameter of inorganic particles determined by dynamic light scattering is, for example, 1 nm or more, preferably 5 nm or more, and, for example, 50 nm or less, preferably 25 nm or less.

The number of parts by mass of inorganic particles per 100 parts by mass of the crosslinked product is, for example, 5 parts by mass or more, preferably 15 parts by mass or more, more preferably 25 parts by mass or more, and for example, 100 parts by mass or less, preferably 70 parts by mass or less, more preferably 40 parts by mass or less.

In addition to the crosslinked material, other additives may be added to the particles. The additives do not include the inorganic particles described above.

The shape of the particles is not particularly limited. Examples of particle shapes include approximately spherical shapes and irregular shapes. An approximately spherical shape is preferred. Examples of approximately spherical shapes include perfect spheres, spheres with depressions (dimpled golf ball shapes), and spheroids. If the particles have an approximately spherical shape, they will have excellent light diffusion properties when a resin composition containing the particles is used for light diffusion purposes.

The median particle diameter is, for example, 1 μm or more, preferably 3 μm or more, more preferably 6 μm or more, and for example, 1000 μm or less, preferably 100 μm or less, more preferably 30 μm or less. If the median particle diameter is equal to or greater than the above-mentioned lower limit (for example, 1 μm), the particles have excellent dispersibility in resin. The median particle diameter can be determined using a laser diffraction/scattering particle size distribution analyzer.

On the other hand, the median diameter of the particles is, for example, less than 1 μm, preferably 750 nm or less, more preferably 500 nm or less, and even more preferably 400 nm or less, and for example, 10 nm or more, preferably 100 nm or more, and more preferably 200 nm or more. If the median diameter of the particles is below the above-mentioned upper limit (for example, 400 nm), Rayleigh scattering occurs, and omnidirectional scattering can be achieved in a light diffuser plate (described below) molded from a resin composition containing the particles. The median diameter of the particles is determined by dynamic light scattering.

The refractive index of the particles is, for example, 1.60 or more, preferably 1.61 or more, more preferably 1.65 or more, and for example, 1.80 or less. When the reaction component contains a first bisarylfluorene derivative, double bonds not conjugated with the fluorene skeleton are converted to single bonds, while the fluorene skeleton, which contributes significantly to the refractive index, remains unreacted. Therefore, the refractive index of the particles can be considered to be substantially the same as the refractive index of the first bisarylfluorene derivative. When the reaction component contains a second bisarylfluorene derivative, epoxy bonds not conjugated with the fluorene skeleton are opened, while the fluorene skeleton, which contributes significantly to the refractive index, remains unreacted. Therefore, the refractive index of the particles can be considered to be substantially the same as the refractive index of the second bisarylfluorene derivative.

Next, a method for producing particles will be described. The method for producing particles comprises a first step of preparing an aqueous dispersion by dispersing a hydrophobic liquid containing a reaction component containing a bisarylfluorene derivative in water, and a second step of polymerizing the aqueous dispersion. Specifically, the method for producing particles comprises a first production method in which a first bisarylfluorene derivative is polymerized in the presence of a polymerization initiator, and a second production method in which a second bisarylfluorene derivative is polymerized with a curing agent. Note that, in this application, polymerization includes radical polymerization of the carbon-carbon double bond of the first bisarylfluorene derivative in the first production method, and further includes a curing reaction in which the epoxy bond of the second bisarylfluorene derivative is cured with a curing agent in the second production method. In both the first and second production methods, polymerization forms a three-dimensional network structure, thereby forming a crosslinked body.

Next, we will explain the first manufacturing method and the second manufacturing method in order.

[First manufacturing method]
The first manufacturing method includes a first step and a second step, and may further include a third step.

In the first step, a hydrophobic liquid is dispersed in water. The hydrophobic liquid contains a first bisarylfluorene derivative and a polymerization initiator.

The polymerization initiator is, for example, a radical polymerization initiator. Examples of polymerization initiators include oil-soluble polymerization initiators. If the polymerization initiator is an oil-soluble polymerization initiator, the hydrophobic liquid in the aqueous dispersion undergoes suspension polymerization or miniemulsion polymerization. The oil-soluble polymerization initiator is not particularly limited. Examples of oil-soluble polymerization initiators include oil-soluble organic peroxides and oil-soluble azo compounds. Examples of oil-soluble organic peroxides include dilauroyl peroxide, t-hexylperoxy-2-ethylhexanoate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, diisopropyl peroxydicarbonate, and benzoyl peroxide. Examples of oil-soluble azo compounds include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(2-methylbutyronitrile). Oil-soluble organic peroxides are preferred as oil-soluble polymerization initiators. Polymerization initiators can be used alone or in combination. The number of parts by mass of the polymerization initiator per 100 parts by mass of the first bisarylfluorene derivative is, for example, 0.01 parts by mass or more, preferably 0.1 parts by mass or more, and for example, 5 parts by mass or less, preferably 3 parts by mass or less.

Furthermore, the hydrophobic liquid may contain, for example, an organic solvent. The first bisarylfluorene derivative is typically a highly viscous liquid or solid. Therefore, it may be difficult to disperse the first bisarylfluorene derivative in water with the desired median diameter. However, if the hydrophobic liquid contains an organic solvent, the organic solvent will reliably dissolve the first bisarylfluorene derivative, preparing a uniform hydrophobic liquid that can then be dispersed in water with the desired median diameter.

The hydrophobic liquid can contain an organic solvent whether the reaction components contain a copolymerizable monomer or not. Preferably, when the reaction components do not contain a copolymerizable monomer, the hydrophobic liquid contains an organic solvent. In this case, the proportion of the first bisarylfluorene derivative in the reaction components can be increased. Therefore, particles with a high refractive index can be produced based on the bisarylfluorene skeleton of the first bisarylfluorene derivative. Furthermore, the particles can be, for example, solid spherical.

On the other hand, when the reaction components contain a copolymerizable monomer, the hydrophobic liquid preferably does not contain an organic solvent. Even if the hydrophobic liquid does not contain an organic solvent, since the reaction components contain a copolymerizable monomer, the liquid copolymerizable monomer can reliably dissolve the highly viscous liquid or solid first bisarylfluorene derivative, preparing a uniform hydrophobic liquid that can be dispersed in water with the desired median diameter. Furthermore, the particles can be, for example, solid spherical.

The organic solvent may be a hydrophobic solvent. The solubility of the hydrophobic solvent in water at 20° C. is, for example, 10 g/100 mL of water or less. The organic solvent preferably has properties such that it is unlikely to boil at 1 atmosphere and at the polymerization temperature, and can be easily removed by distillation after polymerization.
Specifically, the boiling point of the organic solvent at 1 atmospheric pressure is, for example, 65°C or higher and, for example, 130°C or lower.

Examples of organic solvents include ester compounds, ketone compounds, aliphatic hydrocarbon compounds, aromatic hydrocarbon compounds, and halogenated hydrocarbon compounds.

Examples of ester compounds include ethyl acetate, propyl acetate, and butyl acetate. Ethyl acetate is preferred as an ester compound. Examples of ketone compounds include methyl isobutyl ketone and cyclohexanone. Methyl isobutyl ketone is preferred as a ketone compound. Examples of aliphatic hydrocarbon compounds include hexane, cyclohexane, heptane, and octane. Examples of aromatic hydrocarbon compounds include benzene, toluene, and xylene. Examples of halogenated hydrocarbon compounds include dichloroethane and trichloroethane. Organic solvents can be used alone or in combination. Examples of organic solvents include ester compounds, ketone compounds, and aromatic hydrocarbon compounds.

The organic solvent may contain a hydrophilic solvent. The solubility of the hydrophilic solvent in water at 20°C is, for example, greater than 10 g/100 mL of water. Examples of hydrophilic solvents include ketone compounds. Examples of ketone compounds include methyl ethyl ketone. The hydrophilic solvent is used in preparing the additive, and is added in small amounts to the hydrophobic solution when the additive is added to the hydrophobic solution. The proportion of the hydrophilic solvent in the organic solvent is, for example, 20% by mass or less, preferably 15% by mass or less.

The number of parts by mass of the organic solvent per 100 parts by mass of the first bisarylfluorene derivative is, for example, 10 parts by mass or more, preferably 30 parts by mass or more, more preferably 75 parts by mass or more, and for example, 300 parts by mass or less, preferably 175 parts by mass or less, more preferably 125 parts by mass or less.

Combine the above ingredients and stir to prepare a hydrophobic liquid.

In the first step, the hydrophobic liquid described above is dispersed in water. To disperse the hydrophobic liquid in water, for example, an aqueous liquid containing a dispersant, an emulsifier, and water is first prepared, and then the hydrophobic liquid is dispersed in the aqueous liquid. The aqueous liquid is, for example, an aqueous solution in which a dispersant and an emulsifier are dissolved in water. In the aqueous liquid, the dispersant may be dispersed in water. When preparing the aqueous liquid, the components are stirred.

Dispersants include water-soluble polymers and inorganic dispersants. Examples of water-soluble polymers include polyvinyl alcohol, polyvinylpyrrolidone, gelatin, gum arabic, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, cationized starch, polyacrylic acid, sodium salts of polyacrylic acid, styrene-maleic acid copolymers, sodium salts of styrene-maleic acid copolymers, and salts of condensates of aromatic sulfonic acid and formaldehyde. Examples of inorganic dispersants include calcium phosphate, colloidal silica, montmorillonite, magnesium carbonate, aluminum hydroxide, and zinc oxide. Preferred dispersants include polyvinyl alcohol, salts of condensates of aromatic sulfonic acid and formaldehyde, and calcium phosphate.

Polyvinyl alcohol includes fully saponified polyvinyl alcohol and partially saponified polyvinyl alcohol. Partially saponified polyvinyl alcohol is preferred as polyvinyl alcohol. The number of parts by mass of the dispersant per 100 parts by mass of the hydrophobic liquid is, for example, 0.01 parts by mass or more, preferably 0.1 parts by mass or more, and for example, 10 parts by mass or less, preferably 6 parts by mass or less.

Examples of emulsifiers include nonionic emulsifiers and anionic emulsifiers.

Examples of nonionic emulsifiers include polyoxyalkylene alkyl ethers, polyoxyalkylene alkylaryl ethers, polyoxyalkylene aralkylaryl ethers, polyoxyalkylene block copolymers, and polyoxyalkylene aryl ethers. Preferred nonionic emulsifiers include polyoxyalkylene block copolymers, specifically polyoxyethylene polyoxypropylene block copolymers.

Examples of anionic emulsifiers include sodium dioctyl sulfosuccinate, sodium dodecylbenzenesulfonate, sodium lauryl sulfate, sodium alkyldiphenyletherdisulfonate, and phosphate ester-type anionic emulsifiers. Preferred anionic emulsifiers include sodium alkyldiphenyletherdisulfonate and phosphate ester-type anionic emulsifiers.

Emulsifiers can be used alone or in combination. If the polymerization method described below is miniemulsion polymerization, an anionic emulsifier is preferably used as the emulsifier.

The number of parts by mass of emulsifier per 100 parts by mass of hydrophobic liquid is, for example, 0.005 parts by mass or more, preferably 0.01 parts by mass or more, and, for example, 20 parts by mass or less, preferably 10 parts by mass or less.

The number of parts by mass of water per 100 parts by weight of hydrophobic liquid is, for example, 100 parts by mass or more, preferably 150 parts by mass or more, and, for example, 1000 parts by mass or less, preferably 500 parts by mass or less.

Next, the hydrophobic liquid and the aqueous liquid are mixed. Specifically, the hydrophobic liquid is mixed with the aqueous liquid, and the hydrophobic liquid is dispersed in the aqueous liquid. This prepares an aqueous dispersion.

A disperser is used for aqueous dispersion. Examples of dispersers include a homomixer, a disperser, an ultrasonic homogenizer, a pressure homogenizer, a Milder, a Clearmix, and a porous membrane press-fit disperser. A homomixer is preferably used as the disperser. To make the median diameter of the hydrophobic liquid 1 μm or more, the rotation speed of the homomixer is set to, for example, less than 12,000 min ⁻¹ , preferably 10,000 min ⁻¹ or less, or, for example, 1,000 min ⁻¹ or more. On the other hand, to make the median diameter of the hydrophobic liquid less than 1 μm, the rotation speed of the homomixer is set to, for example, 10,000 min ⁻¹ or more, preferably 12,000 min ⁻¹ or more, or, for example, 20,000 min ⁻¹ or less.

The time for water dispersion is, for example, within 30 minutes.

Next, the second step is carried out. In the second step, the aqueous dispersion is polymerized to prepare a particle dispersion. Specifically, the aqueous dispersion is subjected to suspension polymerization or mini-emulsion polymerization.

In the second step, the aqueous dispersion is first heated. The heating temperature and heating time are appropriately selected depending on the type of polymerization initiator. The heating temperature is, for example, 40°C or higher, preferably above 40°C, more preferably 50°C or higher, and, for example, 100°C or lower. The heating time is, for example, 3 hours or longer, preferably 5 hours or longer, and, for example, 24 hours or shorter, preferably 12 hours or shorter. Furthermore, stepwise heating can be performed by heating to a predetermined temperature, maintaining that temperature for a predetermined period, and then repeating heating and maintaining the temperature. If the hydrophobic liquid contains an organic solvent, the organic solvent is distilled off (removed) in the final step of the second step. In other words, the second step further includes an operation to remove the organic solvent. To distill off the organic solvent, in the final step of the second step, the aqueous dispersion is heated to a temperature above the boiling point of the organic solvent or the azeotropic point with water, or the atmosphere surrounding the aqueous dispersion is reduced in pressure. Alternatively, a combination of heating and reducing the pressure may be used.

If the hydrophobic liquid contains an organic solvent and the first bisarylfluorene derivative becomes a low-viscosity liquid at the polymerization temperature, the organic solvent may be removed by vacuum distillation before or during polymerization.

When heated, the polymerization initiator cleaves to generate radicals, and the carbon-carbon double bonds undergo a chain reaction to produce a polymer.

If the median diameter of the hydrophobic liquid in the aqueous dispersion is 1 μm or greater, the reaction will be suspension polymerization. If the median diameter of the hydrophobic liquid is less than 1 μm, the reaction will be miniemulsion polymerization. Suspension polymerization and miniemulsion polymerization are described in detail, for example, in JP 2012-207012, JP 2012-207013, and JP 2016-011299. In miniemulsion polymerization, the first bisarylfluorene derivative contains a hydrocarbon group with 25 or 33 carbon atoms and is present in a large amount in the hydrophobic liquid, so it acts as a hydrophobe.

The two carbon-carbon double bonds in one molecule of the first bisarylfluorene derivative react to form a crosslinked structure in the polymer. In other words, particles made of crosslinked materials are produced.

This produces a particle dispersion in which particles are dispersed in water. A particle dispersion prepared by suspension polymerization is a suspension. A particle dispersion prepared by miniemulsion polymerization is an emulsion.

When the reaction components include a first bisarylfluorene derivative and a copolymerizable monomer, a copolymer of the first bisarylfluorene derivative and the copolymerizable monomer is produced. On the other hand, when the reaction components are only the first bisarylfluorene derivative, a homopolymer of the first bisarylfluorene derivative is produced.

Next, the third step is carried out. In the third step, the suspension or emulsion is separated into solid and liquid and dried to obtain a powder. The method for obtaining a powder from a suspension is described below.

After the suspension polymerization is complete, the suspension is cooled, for example, to below 40°C.

The suspension is then washed and dried.

To wash the suspension, for example, first allow the suspension to stand, then remove the supernatant (dehydrate), and then repeat washing and dehydration using water. A centrifuge or filter press can be used for washing and dehydration. In the third step, if the hydrophobic liquid contains an organic solvent, most of the organic solvent is removed. This results in a wet powder.

The wet powder is then dried.

Methods for drying the wet powder include, for example, heat drying (including shelf drying), fluidized bed drying, vacuum drying, and leaving at room temperature (25°C). Heat drying is preferred. This yields particles.

If the particles have agglomerated, they are then broken down.

This produces particles.

Next, we will explain how to obtain powder from the emulsion.

After the miniemulsion polymerization is complete, the emulsion is cooled, for example, to below 40°C.

The emulsion is then coagulated and dried. Methods for coagulation and drying include coagulation and spray drying. In the coagulation method, particles are coagulated by freezing or salting out, and then washed and dehydrated using a centrifuge or filter press to obtain a wet powder. The wet powder is then dried in the same manner as the suspension. On the other hand, the spray drying method simplifies the process. However, washing is not performed in the spray drying method. Although the coagulation method involves multiple steps, washing is performed. If the size of the coagulated particles needs to be reduced after washing, they are crushed. This results in a powder. Alternatively, a BoCross filter (manufactured by Tsukishima Kikai Co., Ltd.) can be used to wash and separate the emulsion into solid and liquid without coagulating it. This produces a wet cake. The wet cake is dried and crushed as needed.

The first bisarylfluorene derivative, which is the reactive component of the crosslinked material contained in these particles, can be identified, for example, by infrared spectroscopy.

[Second manufacturing method]
The second manufacturing method includes, for example, Method A and Method B. Next, Method A and Method B will be described separately.

[Method A]
Method A includes a first step and a second step.

In the first step, a hydrophobic liquid is dispersed in water. The hydrophobic liquid contains a second bisarylfluorene derivative. The hydrophobic liquid preferably further contains a hydrophobic high-temperature curing agent, i.e., a second curing agent.

Furthermore, the hydrophobic liquid may include, for example, an organic solvent. The type, parts by weight, and function of the organic solvent are the same as those described in the first manufacturing method.

In the first step, the hydrophobic liquid described above is dispersed in water to prepare an aqueous dispersion. The method for aqueous dispersion is the same as that described in the first manufacturing method.

Next, the second step is carried out. In this step, a hydrophilic, low-temperature-curing curing agent, i.e., the first curing agent, is blended into the aqueous dispersion. Preferably, the first curing agent is blended into the aqueous dispersion while heating and stirring the aqueous dispersion. Specifically, an aqueous curing agent solution containing the first curing agent is prepared, and the aqueous curing agent solution is blended into the aqueous dispersion. The proportion of the first curing agent in the aqueous curing agent solution is, for example, 5% by mass or more, preferably 15% by mass or more, and, for example, 40% by mass or less, preferably 30% by mass or less. The heating conditions are the same as those described in the first manufacturing method. If the hydrophobic liquid contains an organic solvent, the organic solvent may be distilled off (removed) in the final stage of the second step. To distill off the organic solvent, in the final stage of the second step, the aqueous dispersion is heated to a temperature above the boiling point of the organic solvent or above the azeotropic point with water, or the atmosphere around the aqueous dispersion is reduced in pressure. Alternatively, a combination of heating and reducing the pressure may be used.

By incorporating a first curing agent into the aqueous dispersion, the second bisarylfluorene derivative reacts with the low-temperature curing agent on the surface of the hydrophobic liquid droplets in the aqueous dispersion. This reaction is referred to as "primary curing" because it is an initial partial cure rather than a complete cure. Because primary curing is a polymerization reaction in the aqueous dispersion, it can be called suspension polymerization if the median diameter of the hydrophobic liquid in the aqueous dispersion is 1 μm or greater. If the median diameter of the hydrophobic liquid is less than 1 μm, it can be called miniemulsion polymerization. In miniemulsion polymerization, the second bisarylfluorene derivative acts as a hydrophobe. The amount of epoxy bonds (remaining epoxy groups) in the second bisarylfluorene derivative after the reaction is appropriately adjusted so that the particle shape can be sufficiently maintained in the third step. In the second step, the reaction preferably proceeds partially due to the second curing agent, i.e., a high-temperature curing agent, incorporated into the hydrophobic liquid (droplets). This reaction is also the primary cure.

After the first curing, the aqueous dispersion after suspension polymerization becomes a suspension. Also, after the first curing, the aqueous dispersion after mini-emulsion polymerization becomes an emulsion.

Next, the third step is carried out. In the third step, the suspension or emulsion is separated into solid and liquid and dried to obtain a powder. The method for obtaining a powder from a suspension is described below.

The suspension is washed and dried in the same manner as in the first manufacturing method for obtaining powder from the suspension. The washing and drying techniques are the same as those in the first manufacturing method. However, after drying, heat drying is performed. The heating temperature is, for example, above 100°C, preferably 110°C or higher, more preferably 120°C or higher, and, for example, 160°C or lower. The heating time is, for example, 0.5 hours or longer, preferably 1 hour or longer, and, for example, 5 hours or shorter.

Next, we will explain how to obtain powder from an emulsion. Solid-liquid separation and drying are carried out in the same way as the method for obtaining powder from an emulsion in the first manufacturing method. In the spray drying method, the powder obtained by solid-liquid separation and drying is heated and dried under the same conditions as for the suspension. In the coagulation method or the solid-liquid separation method using a BoCross filter, once the wet powder has dried, post-curing is carried out under the same conditions as for the dried powder obtained from the suspension.

Drying by heating causes the second bisarylfluorene derivative to further react with a hydrophobic, high-temperature curing curing agent, i.e., a second curing agent. This reaction is not a partial cure but a complete cure, and can be called "secondary cure" or "post-cure." After post-cure, the amount of epoxy bonds in the second bisarylfluorene derivative is essentially zero. This forms a three-dimensional network structure throughout the particle, resulting in the formation of a crosslinked body.

If the particles have agglomerated, they are then broken down.

This produces particles. The particles produced by the second production method may have a particular morphology, for example, a porous shape and/or a spherical shape with indentations.

The secondary bisarylfluorene derivative and curing agent, which are the reactive components of the crosslinked material in these particles, can be identified, for example, by infrared spectroscopy.

[Method B]
In the method B, the second bisarylfluorene derivative is cured using only the third curing agent as a curing agent. The method B includes a first step and a second step.

In the first step of Method B, a hydrophobic liquid is first prepared and dispersed in water. The hydrophobic liquid contains reaction components including a second bisarylfluorene derivative and a third curing agent. It may also contain an organic solvent, if necessary. The methods for preparing the hydrophobic liquid and dispersing it in water are the same as those in the first step of Method A.

Then, in Method B, the second step is carried out. In the second step, the aqueous dispersion is heated and stirred to promote the curing reaction. In the second step, particles consisting of a homogeneous crosslinked product are obtained. The heating conditions are the same as in the second step of Method A. Note that the organic solvent may be distilled off (removed) in the final stage of the second step. The solid-liquid separation and drying steps of the resulting suspension or emulsion may be the same as those in Method A, and the drying temperature is 80 to 100°C.

<Application>
The use of the particles is not particularly limited. For example, the particles and a resin are blended to prepare a resin composition.

The resin is not particularly limited. Examples of resins include transparent resins. Examples of such resins include thermosetting resins and thermoplastic resins.

Examples of thermosetting resins include photocurable transparent coating resins. Examples of coating resins include epoxy acrylates, urethane acrylates, and unsaturated polyester resins. Preferred examples of thermosetting resins include epoxy esters. Epoxy esters are oligomers formed by reacting epoxy resins with (meth)acrylic acid.

Examples of thermoplastic resins include acrylic resins, polystyrene-based resins, polyolefin resins, polyester resins, polycarbonate resins, and thiourethane resins. Examples of acrylic resins include polymethyl methacrylate, polycyclohexyl methacrylate, and polydicyclopentanyl methacrylate. Examples of polystyrene-based resins include polystyrene, styrene-acrylonitrile copolymer, and styrene-methyl methacrylate copolymer. Examples of polyolefin resins include cycloolefin polymer (COP) and cycloolefin copolymer (COC). Examples of polyester resins include polyethylene terephthalate and bisphenoxyethanol fluorene-based polyester. If the resin is a photocurable resin such as an epoxy ester, the resin composition may contain a second polymerization initiator. Examples of the second polymerization initiator include a photopolymerization initiator.

The total light transmittance of the resin is, for example, 70% or more, preferably 80% or more, more preferably 90% or more, and, for example, 100% or less.

The refractive index of the resin at a wavelength of 589 nm is, for example, 1.6 or less, preferably 1.55 or less, and for example, 1.3 or more. If the refractive index of the resin is equal to or less than the upper limit mentioned above (for example, 1.6), the resin is a low refractive index resin. On the other hand, the refractive index of the resin at a wavelength of 589 nm is, for example, greater than 1.6, preferably 1.65 or more, and may be, for example, 1.9 or less. If the refractive index of the resin exceeds the lower limit mentioned above (for example, 1.6), the resin is a high refractive index resin.

The particle content in the resin composition is not limited, but is, for example, 0.1% by mass or more, preferably 0.5% by mass or more, and is, for example, 15% by mass or less, preferably 10% by mass or less.

For example, a resin composition is coated to produce a light-diffusing film. For example, the resin composition is molded to produce a molded article. Examples of molded articles include lenses, films, plates, and threads. Threads include strands. Molded articles are preferably used for optical applications. Examples of molded articles used for optical applications include optical lenses and light-diffusing molded articles. In optical lenses, the refractive index of the matrix resin is adjusted.

Preferred examples of light diffusing molded articles include light diffusing membranes, light diffusing films, and light diffusing plates.

If the coating (resin composition) contains a photopolymerization initiator, it is irradiated with light after application.
The light includes ultraviolet light, which results in a cured coating film.

Examples of molding include extrusion molding and injection molding.

<Effects of particles and manufacturing method thereof>
These particles have a high refractive index and excellent dispersibility in resins. The reactive component contains a bisarylfluorene derivative. Specifically, since the particles contain a first bisarylfluorene derivative or a second bisarylfluorene derivative, they have a high refractive index based on their bisarylfluorene skeleton. Furthermore, two polymerizable carbon-carbon double bonds react, or two epoxy bonds react with a curing agent, forming a three-dimensional network structure. Therefore, the particles do not dissolve in resins, resulting in excellent dispersibility of the particles in resins.

If the reaction components are only the first bisarylfluorene derivative or the second bisarylfluorene derivative and a curing agent, the refractive index of the particles can be increased based on the highly refractive bisarylfluorene skeleton.

On the other hand, if the reaction components contain a first bisarylfluorene derivative and a copolymerizable monomer, and the first bisarylfluorene derivative is a highly viscous liquid or solid, the copolymerizable monomer will dissolve reliably, preparing a uniform hydrophobic liquid that can be dispersed in water with the desired median diameter. Therefore, particles with the desired median diameter can be produced.

If the particles contain inorganic particles with a refractive index of 1.7 or higher dispersed in a size of several tens of nanometers or less, the refractive index of the particles can be further increased.

If the particles have a roughly spherical shape, they will have excellent light diffusion properties when used in a resin composition in which the particles are dispersed in a low refractive index resin for light diffusion purposes.

If the particles have an approximately spherical shape, the resin composition in which the particles are dispersed in a high refractive index resin can maintain transparency and allow for fine adjustment of the refractive index.

Particles with a median diameter of 1 μm or greater have excellent dispersibility in resin.

If the median particle diameter is less than 1 μm, preferably 400 nm or less, the resin composition containing the particles can scatter light in all directions in a light-diffusing molded article.

This particle manufacturing method involves dispersing a hydrophobic liquid containing reactive components in water, allowing for the production of particles with the desired median diameter and excellent dispersibility.

Transparent sheets coated with a coating agent made from a transparent resin composition with the above-mentioned particles dispersed therein exhibit excellent light diffusion properties.

In a transparent resin composition in which the above-mentioned particles are dispersed in a low refractive index resin, the high refractive index particles are well dispersed in the low refractive index resin, so when a light-diffusing molded article is molded from the resin composition, it exhibits excellent light diffusion properties.

Light diffusion properties are evaluated by haze (see Examples below). If the haze of a light diffusion molded product is high, it indicates that the light diffusion molded product has excellent light diffusion properties.

In addition, coating films or molded films made from resin compositions in which the above particles are dispersed can improve light diffusion and suppress a decrease in total light transmittance.

Specific numerical values for blending ratios (content ratios), physical properties, parameters, etc. used in the following description can be replaced with the upper limit (defined as "not more than" or "less than") or lower limit (defined as "not less than" or "exceeding") of the corresponding blending ratios (content ratios), physical properties, parameters, etc. described in the "Description of the Invention" above. Furthermore, unless otherwise specified, "%" refers to % by mass.

Details of the components used in each example and comparative example are given below.
BPEF-A: 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, a primary bisarylfluorene derivative represented by formula (1), manufactured by Osaka Gas Chemicals Co., Ltd. BNFG: 9,9-bis(6-glycidyloxy-2-naphthyl)fluorene, a secondary bisarylfluorene derivative represented by formula (5), manufactured by Osaka Gas Chemicals Co., Ltd. FBP-GX: a bisarylfluorene-based polyester resin of bisethoxyphenolfluorene/ethylene glycol/terephthalic acid=70/30/100 (molar ratio), manufactured by Osaka Gas Chemicals Co., Ltd. Perloyl L: trade name, dilauroyl peroxide, oil-soluble polymerization initiator, 10-hour half-life temperature 62°C, manufactured by NOF Corporation Perhexyl O: trade name, t-hexylperoxy-2-ethylhexanoate, oil-soluble polymerization initiator, 10-hour half-life temperature 70°C, manufactured by NOF Corporation. Poval 22-88: trade name, partially saponified polyvinyl alcohol (saponification degree 88%), dispersant (water-soluble polymer), manufactured by Kuraray Co., Ltd. Poval 5-74: trade name, partially saponified polyvinyl alcohol (saponification degree 74%), dispersant (water-soluble polymer), manufactured by Kuraray Co., Ltd. TCP-10U: trade name, 10% calcium phosphate slurry, dispersant, manufactured by Taihei Chemical Industry Co., Ltd. Pronon 208: trade name, polyoxyethylene polyoxypropylene block copolymer, nonionic emulsifier, manufactured by NOF Corporation. Plysurf A210G: trade name, phosphate ester-type anionic emulsifier, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. Demol NL: trade name, 41% aqueous solution of β-naphthalenesulfonic acid formaldehyde condensate sodium salt, dispersant, manufactured by Kao Corporation. Pelex SSL: trade name, alkyldiphenyletherdisulfonate sodium, anionic emulsifier, manufactured by Kao Corporation. Ethyl acetate: reagent, solubility in water: 8 g/100 mL (20°C), boiling point 84°C, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Toluene: reagent, solubility in water: 0.047 g/100 mL (20°C), boiling point 111°C, azeotropic point with water 85°C, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. MIBK: methyl isobutyl ketone, reagent, solubility in water: 1.9 g/100 mL (20°C), boiling point 116°C, azeotropic point with water 84°C (actual measurement), manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Styrene: reagent, viscosity at 25°C 0.7 mPa·s, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Divinylbenzene: Reagent, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. 2E4MZ: "Curesol 2E4MZ", 2-ethyl-4-methylimidazole, second curing agent, molecular weight 110, manufactured by Shikoku Kasei Corporation DETA: Reagent, diethylenetriamine, chain aliphatic polyamine compound, first curing agent, molecular weight 103, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. 1,3-xylylenediamine: Reagent, aromatic aliphatic polyamine compound, third curing agent, molecular weight 136, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. jER806: Bis-F type liquid epoxy resin, epoxy equivalent 160 to 170, manufactured by Mitsubishi Chemical Corporation Zirconia sol: "Zircostar ZP-153" manufactured by Nippon Shokubai Co., Ltd., particle content 70% by mass, dispersion medium: methyl ethyl ketone, particle diameter 11 nm, particle refractive index 1.8

( Comparative Example 5 )
A homogeneous hydrophobic liquid (hydrophobic solution) was prepared by charging 50.00 parts by mass of ethyl acetate, 50.00 parts by mass of BPEF-A, and 0.25 parts by mass of Perloyl L into a beaker and stirring at 25° C. Separately, a homogeneous aqueous solution was prepared by charging 258.72 parts by mass of deionized water, 40.00 parts of a 10% aqueous solution of Poval 22-88, 0.03 parts by mass of Demol NL, and 1.00 parts by mass of a 1% aqueous solution of Pronon 208 into a beaker and stirring at 25° C.

Next, the hydrophobic liquid was added to the aqueous solution, and the mixture was stirred for 10 minutes at a rotation speed of 6,000 min ^-1 using a T.K. Homomixer MARK2.5 (manufactured by Primix Corporation) to disperse the hydrophobic liquid in the aqueous solution, thereby preparing an aqueous dispersion.

The aqueous dispersion was then transferred to a four-neck flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen inlet tube. Under a nitrogen stream, the four-neck flask was heated using a water bath while stirring, and suspension polymerization was carried out. The suspension polymerization was initiated when the temperature reached 65°C, and then continuously carried out at 70±2°C for 3 hours and at 75±2°C for 3 hours. Subsequently, a line for recovering ethyl acetate from the reflux condenser was set up, the temperature was raised to 84°C or higher, and the ethyl acetate was distilled off for 1 hour. The reaction solution was then cooled to 30°C or lower to obtain a suspension containing particles composed of a homopolymer of BPEF-A. The suspension was measured using a laser diffraction/scattering particle size distribution analyzer LA-960V2 (manufactured by Horiba, Ltd.) to determine the median particle size. The median diameter was 11.5 μm. In the following Example 2, Comparative Examples 7 to 13, Example 11, and Comparative Example 1, the median particle size was determined using the same method.

The suspension was left to stand overnight, and the supernatant was removed (the water containing ethyl acetate was dehydrated). The suspension was then washed with deionized water using a centrifuge and dehydrated repeatedly, yielding a white wet powder. This wet powder was shelf-dried at 60°C and then crushed to obtain particles.

Example 2
Particles made of a copolymer of BPEF-A and styrene were obtained in the same manner as in Comparative Example 5 , except that 50.00 parts by mass of styrene was used instead of 50.00 parts by mass of ethyl acetate and the solvent distillation step was omitted. The median diameter of the particles was 12.4 μm.

( Comparative Example 6 )
A beaker was charged with 50.00 parts by mass of ethyl acetate, 50.00 parts by mass of BPEF-A, and 0.25 parts by mass of Peroyl L, and the mixture was stirred at 25° C. to prepare a uniform hydrophobic liquid.

Separately, 107.80 parts by mass of deionized water, 40.00 parts by mass of a 10% aqueous solution of Poval 22-88, and 2.00 parts by mass of Pelex SS-L were charged into a beaker and stirred at 25°C to prepare a uniform aqueous solution.

Next, the hydrophobic liquid was added to the aqueous solution, and the mixture was stirred for 10 minutes at a rotation speed of 14,000 min ^-1 using a T.K. Homomixer MARK2.5 (manufactured by Primix Corporation), thereby dispersing the hydrophobic liquid in the aqueous solution and preparing an aqueous dispersion.

The aqueous dispersion was then transferred to a four-neck flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen inlet tube. Miniemulsion polymerization was then performed by heating the flask in a water bath under a nitrogen stream while stirring. The polymerization began when the temperature reached 65°C, and was then carried out continuously at 70±2°C for 3 hours and at 80±2°C for 2 hours. A line for recovering ethyl acetate was then set up from the reflux condenser, and the temperature was raised to above 84°C, followed by distillation of the ethyl acetate for 1 hour. The reaction solution was then cooled to below 30°C, yielding an emulsion containing particles composed of BPEF-A homopolymer. The emulsion was measured using a dynamic light scattering particle size analyzer, FPAR-1000 (Otsuka Electronics Co., Ltd.), to determine the median particle size. The median particle size was 382 nm. The emulsion was then coagulated by the freeze-thaw method, and the supernatant was removed from the resulting emulsion (dehydrated). This emulsion was washed with deionized water using a centrifuge and repeatedly dehydrated to obtain a white wet powder. This wet powder was shelf-dried at 60°C and then crushed to obtain particles.

( Comparative Example 12 )
A uniform hydrophobic liquid was prepared by placing 50.0 parts by mass of ethyl acetate, 47.5 parts by mass of BNFG, and 2.5 parts by mass of 2E4MZ in a beaker and stirring at 25° C. Separately, 279.0 parts by mass of deionized water, 40.0 parts by mass of a 10% aqueous solution of Poval 22-88, and 1.0 part by mass of a 1% aqueous solution of Pronon 208 in a beaker and stirring at 25° C. to prepare a uniform aqueous solution.

Next, the hydrophobic liquid was added to the aqueous solution, and the mixture was stirred for 10 minutes at a rotation speed of 6,000 min ^-1 using a T.K. Homomixer MARK2.5 (manufactured by Primix Corporation) to disperse the hydrophobic liquid in the aqueous solution, thereby preparing an aqueous dispersion.

The aqueous dispersion was then transferred to a four-neck flask equipped with a stirrer, reflux condenser, and thermometer. The flask was heated using a water bath while stirring, allowing for suspension polymerization (primary curing). The suspension polymerization reaction (primary curing with DETA) began when the temperature reached 65°C and 10.0 parts by weight of a 24% by weight aqueous solution of DETA was added. The reaction was then carried out continuously at 65±2°C for 2 hours, 70±2°C for 2 hours, and 75±2°C for 2 hours. A line for recovering ethyl acetate was then set up from the reflux condenser, and the temperature was raised to above 84°C, and the ethyl acetate was distilled off for 1 hour. The reaction solution was then cooled to below 30°C, yielding a suspension containing particles consisting of partially cured BNFG. The median particle diameter of the particles was 12.2 μm.

The suspension was left to stand overnight, and the supernatant was removed (the water containing ethyl acetate was dehydrated). The suspension was then washed with deionized water using a centrifuge and dehydrated repeatedly, yielding a white wet powder. This wet powder was shelf-dried at 60°C, then dried and post-cured (secondary curing with 2E4MZ) at 130°C for 3 hours, and then crushed to obtain particles.

( Comparative Example 7 )
A hydrophobic liquid was prepared by charging 50.0 parts by mass of ethyl acetate, 50.00 parts by mass of BPEF-A, 24.0 parts by mass of zirconia sol, and 0.10 parts by mass of Perloyl L into a beaker and stirring at 25°C. Zirconia particles were dispersed in the hydrophobic liquid. Separately, a beaker was charged with 278.5 parts by mass of deionized water, 20.0 parts by mass of a 10% aqueous solution of Poval 22-88, and 1.0 part by mass of a 1% aqueous solution of Pronon 208, and stirring at 25°C to prepare a uniform aqueous solution.

Next, the hydrophobic liquid was added to the aqueous solution, and the mixture was stirred for 10 minutes at a rotation speed of 6,000 min ^-1 using a T.K. Homomixer MARK2.5 (manufactured by Primix Corporation) to disperse the hydrophobic liquid in the aqueous solution, thereby preparing an aqueous dispersion.

The aqueous dispersion was then transferred to a four-necked flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen inlet tube. Under a nitrogen stream, the four-necked flask was heated using a water bath while stirring, and suspension polymerization was carried out. The suspension polymerization began when the temperature reached 65°C, and was then carried out continuously for three hours at 70±2°C and three hours at 75±2°C. A line for recovering ethyl acetate was then set up from the reflux condenser, and the temperature was raised to above 84°C, and the ethyl acetate was distilled off for one hour. The reaction solution was then cooled to below 30°C, yielding a suspension containing particles consisting of a homopolymer of BPEF-A. The median particle diameter was 11.9 μm.

The suspension was left to stand overnight, and the supernatant was removed (the water containing ethyl acetate was dehydrated). The suspension was then washed with deionized water using a centrifuge and dehydrated repeatedly, yielding a white wet powder. This wet powder was shelf-dried at 60°C and then crushed to obtain particles. Observation using SEM-EDX (scanning electron microscope-energy dispersive X-ray analysis) revealed that zirconia nanoparticles were dispersed within the particles.

(Comparative Example 1)
According to Comparative Example 5 of JP 2009-167231 A, FBP-GX and Poval 5-74 were kneaded to prepare a compound with a PVA continuous phase, which was then pulverized and the PVA was removed by dissolving in water to obtain spherical particles. The median diameter of the particles was 10.1 μm.

(Comparative Example 2)
Crosslinked MMA-styrene copolymer beads "GMS-6121" (manufactured by Koyu Seika Co., Ltd.) were prepared as particles for Comparative Example 2. The median diameter of these particles was 12 μm according to the catalog value.

(Comparative Example 3)
Cross-linked polystyrene beads "GS-1105" (manufactured by Aica Kogyo Co., Ltd.) were prepared as particles for Comparative Example 3. The median diameter of these particles was 11 μm according to the catalog value.

(Comparative Example 4)
A four-neck flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube was charged with 80.00 parts of deionized water, 0.20 parts of Pelex SSL, and 0.10 parts of sodium hydrogen carbonate, and the mixture was heated to 60° C. with stirring under a nitrogen stream. 2.00 parts of styrene and 0.20 parts of divinylbenzene were added, and after 5 minutes, 0.10 parts of potassium persulfate was added to initiate emulsion polymerization.
The temperature was then raised to 75°C, and a monomer emulsion prepared by emulsifying a monomer solution consisting of 87.80 parts of styrene and 10.00 parts of divinylbenzene in an aqueous solution consisting of 105.00 parts of deionized water, 1.80 parts of Pelex SSL, 0.2 parts of sodium bicarbonate, and 0.5 parts of sodium persulfate was continuously fed over 4 hours. After further aging at 80°C for 1 hour, the mixture was cooled to 40°C or below to obtain an emulsion containing particles made of cross-linked polystyrene. The median particle size of the particles measured using a dynamic light scattering particle size analyzer FPAR-1000 (manufactured by Otsuka Electronics Co., Ltd.) was 305 nm.

The emulsion was coagulated using the freeze-thaw method, and the supernatant was removed (dehydrated). The emulsion was then washed with deionized water using a centrifuge and dehydrated repeatedly to obtain a white wet powder. This wet powder was shelf-dried at 60°C and subsequently crushed to obtain particles.

( Comparative Example 8 )
A uniform hydrophobic liquid (hydrophobic solution) was prepared by placing 40.00 parts by mass of toluene, 60.00 parts by mass of BPEF-A, and 0.50 parts by mass of Perhexyl O in a beaker and stirring at 25° C. Separately, a uniform aqueous solution was prepared by placing 139.3 parts by mass of deionized water, 60.00 parts by mass of TCP-10U, and 0.20 parts by mass of a 5% aqueous solution of Plysurf A210G in a beaker and stirring at 25° C.

Next, the hydrophobic liquid was added to the aqueous solution, and the mixture was stirred for 10 minutes at a rotation speed of 8,000 min ^-1 using a T.K. Homomixer MARK2.5 (manufactured by Primix Corporation), thereby dispersing the hydrophobic liquid in the aqueous solution and preparing an aqueous dispersion.

The aqueous dispersion was then transferred to a four-necked flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen inlet tube. Under a nitrogen stream, the four-necked flask was heated using a water bath while stirring, and suspension polymerization was carried out. The suspension polymerization was initiated when the temperature reached 70°C, and was carried out continuously for 1 hour at 70±2°C and 3 hours at 80±2°C. Next, a line was set up to recover toluene from the reflux condenser, and the temperature was raised to above 85°C, and the toluene was distilled off for 3 hours. The reaction solution was then cooled to below 30°C, yielding a suspension containing particles consisting of a homopolymer of BPEF-A. The median particle diameter of the suspension was 6.9 μm.

The suspension was left to stand overnight, and the supernatant was removed (the water containing toluene was dehydrated). The suspension was then washed with deionized water using a centrifuge and dehydrated repeatedly, yielding a white wet powder. This wet powder was shelf-dried at 60°C and then crushed to obtain particles.

( Comparative Example 9 )
Except for using MIBK instead of toluene, particles were obtained using the same recipe and procedure as in Comparative Example 8. The median particle size was 12.1 μm.

( Comparative Example 10 )
Particles were obtained using the same recipe and procedure as in Comparative Example 9 , except that the dispersion conditions using the homomixer were changed to 10,000 min ⁻¹ for 10 minutes. The median particle size was 8.4 μm.

( Comparative Example 11 )
Particles were obtained using the same recipe and procedure as in Comparative Example 9 , except that the dispersion conditions using the homomixer were changed to 12,000 min ⁻¹ for 10 minutes. The median particle size was 6.2 μm.

( Comparative Example 13 )
A uniform hydrophobic liquid was prepared by placing 50.0 parts by mass of MIBK and 50.0 parts by mass of BNFG in a flask, stoppering the flask, heating the flask to 40°C, and stirring with a magnetic stirrer. Separately, 235.0 parts by mass of deionized water, 40.0 parts by mass of a 10% aqueous solution of Poval 22-88, and 2.4 parts by mass of an aqueous Demol N solution were placed in a beaker, and stirring was carried out at 25°C to prepare a uniform aqueous solution.

Next, the hydrophobic liquid was returned to room temperature, and then 7.5 parts by mass of 1,3-xylylenediamine was added to the hydrophobic liquid and mixed uniformly. This hydrophobic liquid was then added to the aqueous solution, and the mixture was stirred for 10 minutes at a rotation speed of 6,000 min ^-1 using a T.K. Homomixer MARK2.5 (manufactured by Primix Corporation) to disperse the hydrophobic liquid in the aqueous solution, thereby preparing an aqueous dispersion.

The aqueous dispersion was then transferred to a four-neck flask equipped with a stirrer, reflux condenser, and thermometer. The four-neck flask was heated using a water bath while stirring, and suspension polymerization was carried out. The suspension polymerization began when the temperature reached 70°C, and was then carried out continuously for 4 hours at 70±2°C and 2 hours at 75±2°C. A line for recovering MIBK was then set up from the reflux condenser, and the temperature was raised to above 84°C, and the MIBK was distilled off for 3 hours. The reaction solution was then cooled to below 30°C, yielding a suspension containing particles consisting of a BNFG homopolymer. The median particle diameter was 6.4 μm.

The suspension was left to stand overnight and the supernatant was removed. The suspension was then washed with deionized water using a centrifuge and repeatedly dehydrated to obtain a white wet powder. This wet powder was then dried under reduced pressure at 60°C and subsequently crushed to obtain particles.

Example 11
Particles were obtained using the same recipe and procedure as in Comparative Example 13 , except that 40.0 parts by mass of MIBK, 40.0 parts by mass of BNFG, and 10 parts by mass of jER806 were used instead of 50.0 parts by mass of MIBK and 50.0 parts by mass of BNFG. The median diameter of the particles was 6.2 μm.

<Evaluation of particle properties>
The following physical properties and evaluations were carried out, and the results are shown in Tables 1 and 2.

[Refractive index]
The refractive index at a wavelength of 589 nm of the particles of Examples 2 and 11 and Comparative Examples 5 to 13 was measured by the immersion method (Becke line method) using an optical microscope and a refractive index standard solution.

[Particle dispersibility]
95 parts by mass of acrylic resin (Sumipex HT55X, manufactured by Sumitomo Chemical Co., Ltd.) was dry-blended with 5 parts by mass of the particles of Comparative Example 5 , and the mixture was melt-kneaded at a cylinder temperature of 250°C using a twin-screw extruder Process 11 manufactured by Thermo Fisher Scientific to form a strand. The strand of Comparative Example 5 was transparent. Meanwhile, the particles of Comparative Example 1 were also treated in the same manner as above. The strand of Comparative Example 1 was opaque and milky white.

Figures 1 and 2 show image-processed SEM photographs of the fracture surfaces of the strands of Comparative Example 5 and Comparative Example 1, respectively. As can be seen from Figure 1, the particle shapes were maintained intact and dispersed in the strand of Comparative Example 5. The dispersibility of Comparative Example 5 was evaluated as "Good."

On the other hand, as can be seen from Figure 2, a uniform phase was formed in the strands of Comparative Example 1. In other words, the presence of particles in Comparative Example 1 could not be confirmed. Comparative Example 1 was rated "X".

Ten parts by mass of each of the particles of Example 2, Comparative Example 12 , and Comparative Examples 2 to 7 were blended with 90 parts by mass of an epoxy ester resin (Epolite 70PA(N), manufactured by Kyoeisha Chemical Co., Ltd.) and dispersed to primary particles using a paint shaker (manufactured by Toyo Seiki Seisakusho, Ltd.) to prepare a mixed resin. A photocurable coating composition was prepared by adding 3 parts by mass of a photopolymerization initiator "Omnirad 184" (manufactured by IGM Resins) to 100 parts by mass of the mixed resin. The coating composition was applied to a PET film "PET A-4300" (thickness: 100 μm) (manufactured by Toyobo Co., Ltd.) using a #9 bar coater to a coating thickness of 20 μm. The coating film was irradiated with ultraviolet light and cured to obtain a coating film (cured film). The irradiation dose was 500 mJ/ ^m² . The haze and total light transmittance of the coating film were measured using a color and turbidity simultaneous measuring instrument COH-400 (manufactured by Nippon Denshoku Industries Co., Ltd.) with n=5. The results are shown in Table 1.

A separate coating film was obtained as a control, but without any particles. The haze and total light transmittance of the control coating film were 15.9% and 91.9%, respectively.

[Haze and total light transmittance of molded sheet]
The particles of Example 11 and Comparative Examples 3, 8 to 11 , and 13 were dry-blended with acrylic resin Sumipex (HT55X, manufactured by Sumitomo Chemical Co., Ltd.) in the amounts shown in Table 2, and molded into a 50 x 40 x 2 mm thick sheet (molded sheet) using a precision injection molding machine (Si-15V, manufactured by Toyo Machinery & Metal Co., Ltd.) under conditions of a cylinder temperature of 250°C, a nozzle temperature of 250°C, a mold temperature of 80°C, and a pressure holding time and cooling time of 20 seconds. The molded sheet was homogeneous and in a well-dispersed state.

The haze and total light transmittance of the molded sheets were measured using a haze meter NDH4000 (manufactured by Nippon Denshoku Industries Co., Ltd.) with n=5. The results are shown in Table 2.

For the same amount of particles added, the higher the refractive index of the particles, the higher the haze, i.e., the higher the light diffusion.

As a control, a sheet without any particles was molded separately. The haze and total light transmittance of the control molded sheet were 48.7% and 91.8%, respectively.

Claims (7)

The crosslinked product includes a first bisarylfluorene derivative having two polymerizable carbon-carbon double bonds and a crosslinked product of reaction components including a copolymerizable monomer;
The particles, wherein the copolymerizable monomer contains at least one selected from the group consisting of styrene, p-methylstyrene, o-methylstyrene, and α-methylstyrene. A particle comprising a crosslinked product of reaction components including a second bisarylfluorene derivative having two epoxy bonds, an epoxy resin, and a curing agent. The particles described in claim 1 or 2 contain inorganic particles having a refractive index of 1.7 or higher. The particles described in any one of claims 1 to 3 have a substantially spherical shape. Particles described in any one of claims 1 to 4, having a median diameter of 1 μm or more. 5. The particles of claim 1 , wherein the median diameter is less than 1 μm. Resin and
A resin composition comprising the particles according to any one of claims 1 to 6.