Composite particles, varnishes, coatings, and adhesives

Abstract

To provide a composite particle with which a coating film excellent in index of refraction and transparency can be simply and efficiently manufactured.SOLUTION: A composite particle includes a compound having a dinaphthothiophene skeleton, and a resin.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to composite particles, varnishes, coating agents, and adhesives.

Background Art

[0002] Compounds having a dinaphthothiophene skeleton (hereinafter referred to as "dinaphthothiophene derivatives") are known to be usable as high refractive index materials, and are expected to be applied to uses such as optical films, coating films, optical lenses, and refractive index improvers that require high refractive index and high transparency. For example, Patent Document 1 describes a refractive index improver containing a compound having a predetermined dinaphthothiophene skeleton, and a resin composition, polymerization or curable composition, and optical material containing the same, for the purpose of providing a novel refractive index improver using an organic compound, and a resin composition, polymerization or curable composition, and optical material containing the same.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a dinaphthothiophene derivative is used alone as a refractive index improver, the dinaphthothiophene derivative is dispersed or dissolved in a solvent, and then applied to a substrate whose refractive index is to be improved, etc., and the solvent is volatilized. However, in that case, there is a high possibility that the problem of a decrease in transparency occurs due to precipitation of crystals of the dinaphthothiophene derivative.

[0005] Furthermore, for applications in optical materials, curable compositions containing a dinaphthothiophene derivative with a predetermined functional group and a reaction initiator that reacts with the functional group upon heating or light irradiation are being investigated. However, there is a need for dinaphthothiophene derivatives and compositions thereof that can be used in the production of optical materials in a simpler and more efficient manner.

[0006] Therefore, based on the above findings, the present invention aims to provide composite particles, varnishes, coating agents, and adhesives that can easily and efficiently produce coating films with excellent refractive index and transparency. [Means for solving the problem]

[0007] As a result of diligent research by the inventors, we have discovered that composite particles obtained by compounding a dinaphthothiophene derivative with a resin can be used to easily and efficiently produce coating films with excellent refractive index and permeability, thus completing the present invention.

[0008] The present invention includes the following embodiments. [1] A composite particle comprising a compound having a dinaphthothiophene skeleton and a resin. [2] The average particle diameter of the composite particles is 1 μm or more. [1] The composite particles described above. [3] The composite particles according to [1] or [2], wherein the compound comprises a compound having a nanofiber-like dinaphthothiophene skeleton. [4] The composite particle according to [3], wherein the thickness of the compound is 1 μm or less. [5] The composite particle according to any one of [1] to [4], wherein the compound is a compound represented by the following formula (1), or a polymer containing a structural unit derived from the compound represented by the following formula (1). [ka] (In the formula, R 1Each of these is independently an organic group, a hydroxyl group, an amino group, a nitro group, a thiol group, a sulfo group, a halogen atom, or an optionally substituted silyl group, and R 2 Each of these is independently an organic group, a hydroxyl group, an amino group, a nitro group, a thiol group, a sulfo group, a halogen atom, or an optionally substituted silyl group; each of these is independently an integer between 0 and 2; and each of these is independently an integer between 0 and 4. [6] A varnish comprising a compound having a dinaphthothiophene skeleton, a resin, and a solvent. [7] The varnish according to [6], wherein the compound comprises a compound having a nanofiber-like dinaphthothiophene skeleton. [8] The varnish according to [7], wherein the thickness of the compound is 1 μm or less. [9] A coating agent or adhesive comprising composite particles as described in any of [1] to [5], or a varnish as described in any of [6] to [8]. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide composite particles, varnishes, coating agents, and adhesives that can easily and efficiently produce coating films with excellent refractive index and transparency. [Brief explanation of the drawing]

[0010] [Figure 1] This is a conceptual diagram showing a composite particle containing a dinaphthothiophene derivative and a resin. [Figure 2] This is a scanning electron microscope image showing the composite particles prepared in the example. [Figure 3] This is the powder X-ray diffraction measurement profile of the composite particles prepared in the example. [Figure 4] This is the investigative scanning calorimetry profile of the composite particles prepared in the example. [Figure 5] This is the scan calorimetry profile of the mixed powder before the composite particles were prepared in the example. [Figure 6] Scanning electron microscope photograph image showing the composite particles fabricated in the examples. [Figure 7] Powder X-ray diffraction measurement profile of the composite particles fabricated in the examples. [Figure 8] Differential scanning calorimetry measurement profile of the composite particles fabricated in the examples. [Figure 9] Differential scanning calorimetry measurement profile of the mixed powder before fabricating the composite particles in the examples. [Figure 10] Scanning electron microscope photograph image showing the mixed powder fabricated in the examples. [Figure 11] Scanning electron microscope photograph image showing the composite particles fabricated in the examples. [Figure 12] Measurement profile of the refractive index and extinction coefficient of the coating film fabricated using the varnish of the examples. [Figure 13] Measurement profile of the refractive index and extinction coefficient of the coating film fabricated using the varnish of the examples.

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention (hereinafter referred to as "the present embodiments") will be specifically described, but the present invention is not limited thereto, and various modifications are possible without departing from the gist thereof.

[0012] In the present embodiments, "particle" does not refer to a perfect sphere and includes various known shapes. Such shapes are not particularly limited, and examples include needle shape, rod shape, and elliptical shape.

[0013] In the present embodiments, "having crystallinity" means that the X-ray diffraction measurement spectrum obtained by X-ray diffraction measurement (XRD) has diffraction peaks. Having crystallinity is considered to mean having a laminated structure in which molecules are arranged.

[0014] In this embodiment, "nanofiber-like" refers to a fiber thickness of approximately 1.0 to 1000 nm.

[0015] 1. Composite particles The composite particles of this embodiment include dinaphthothiophene derivative particles and resin particles, and may contain other components as needed. The reasons why the composite particles of this embodiment can easily and efficiently produce coatings with excellent refractive index and permeability are as follows: The dinaphthothiophene derivative contained in the composite particles exhibits a very high refractive index whether it is a compound alone or a mixture with resin. Therefore, by including the dinaphthothiophene derivative in the composite particles, it is possible to produce coatings with excellent refractive index. In addition, by including resin in addition to the dinaphthothiophene derivative in the composite particles, uneven distribution of the shape and / or crystallinity of each component in the composite particles is less likely to occur, and it is possible to produce coatings with excellent permeability. Furthermore, since coatings can be produced simply by using the composite particles as a powder or varnish, coatings can be produced easily and efficiently.

[0016] Figure 1 is a conceptual diagram showing a composite particle containing a dinaphthothiophene derivative and a resin. For example, composite particle 1 contains multiple nanofibers 11 of dinaphthothiophene derivatives and multiple resin particles 12.

[0017] In this embodiment, "composite particles" refers to secondary particles formed by the physical association, aggregation, or bonding of two or more components, including a dinaphthothiophene derivative and a resin. In the composite particles of this embodiment, the uneven distribution of shape and / or crystallinity derived from the two or more components contained in the composite particles is extremely unlikely to occur, and therefore they are clearly distinguishable from mixtures in which uneven distribution of shape and / or crystallinity occurs (for example, the mixed powder described in the examples).

[0018] The average particle size of the composite particles is preferably 1 μm or more, more preferably 10 μm or more, even more preferably 50 μm or more, and even more preferably 100 μm or more. Furthermore, there is no particular upper limit to the average particle size of the composite particles, but for example, it is 1000 μm. Having the average particle size of the composite particles within this range allows the powdered composite particles to have excellent fluidity, preventing the generation of dust during handling and enabling simpler and more efficient handling.

[0019] Furthermore, the mass ratio (A / B) of the content of dinaphthothiophene derivative particles (A) to the content of resin (B) in the composite particles is preferably 1.0 to 5.0, more preferably 1.5 to 4.0, and even more preferably 2.0 to 3.0. When the mass ratio (A / B) is within this range, the dinaphthothiophene derivative and resin in the composite particles tend to be more uniformly intermingled.

[0020] In this embodiment, the average particle diameter of the composite particles is determined using a scanning electron microscope (SEM). Specifically, the composite particles are photographed with an SEM, 10 particles are randomly selected from the multiple composite particles captured, and the average value of the longitudinal lengths of these composite particles is taken as the average particle diameter. Specific conditions for the SEM can be, for example, those described in the examples.

[0021] The crystallinity of composite particles can be evaluated by powder X-ray diffraction (XRD). Specific conditions for XRD include, for example, those described in the examples.

[0022] 1.1. Dinaphthothiophene derivatives In this embodiment, the dinaphthothiophene derivative is preferably crystalline (i.e., crystalline) from the viewpoint of more effectively and reliably achieving the effects of the present invention. Furthermore, the shape of the dinaphthothiophene derivative when it is in the form of particles is not particularly limited, but examples include fibrous, needle-shaped, rod-shaped, and spherical.

[0023] The dinaphthothiophene derivative preferably includes a nanofiber-type dinaphthothiophene derivative. The inclusion of such a nanofiber-type dinaphthothiophene derivative tends to increase the stability of the nanocrystals dispersed in the composite particles.

[0024] When the dinaphthothiophene derivative is in the form of particles, its average particle size is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 1.0 μm or less. The lower limit of the average particle size is not particularly limited, but may be, for example, 20 nm, 50 nm, or 100 nm.

[0025] When the dinaphthothiophene derivative includes a nanofiber-like dinaphthothiophene derivative, the length of the nanofiber is not particularly limited.

[0026] Furthermore, the thickness of the nanofiber is preferably 200 nm or less, more preferably 150 nm or less, and even more preferably 100 nm or less. The lower limit of its thickness is not particularly limited, but for example, it may be 10 nm, 30 nm, or 50 nm.

[0027] The aspect ratio (length / thickness) of the above nanofiber is preferably 10 or more, more preferably 50 or more, and even more preferably 100 or more. The upper limit of the aspect ratio is not particularly limited, but may be, for example, 500, 1000, or 5000.

[0028] In this embodiment, the average particle size of the dinaphthothiophene derivative particles is determined using a scanning electron microscope (SEM). Specifically, the composite particles are imaged with an SEM, 10 dinaphthothiophene derivative particles are randomly selected from those imaged, and the average length of these dinaphthothiophene derivative particles is taken as the average particle size. Specific SEM conditions can be, for example, those described in the examples.

[0029] Furthermore, to determine the length and thickness of the nanofibers, nanofibers are imaged using a scanning electron microscope (SEM), and 10 nanofibers are randomly selected from the multiple nanofibers captured. The average length in the longitudinal direction and the average length in the transverse direction of these nanofibers are then defined as the length and thickness of the nanofiber crystal, respectively.

[0030] From the viewpoint of obtaining a high refractive index, the content of the dinaphthothiophene derivative is preferably 50% by mass or more, and more preferably 70% by mass or more, relative to the total mass of the composite particles. Furthermore, the content of the dinaphthothiophene derivative is preferably 90% by mass or less. When the content of the dinaphthothiophene derivative is 90% by mass or less, it becomes easier to manufacture the composite particles, and when used as a varnish as described later, crystals of the dinaphthothiophene derivative are less likely to precipitate in the resulting coating film, and the permeability tends to be improved. From this viewpoint, the content of the dinaphthothiophene derivative is more preferably 80% by mass or less.

[0031] The higher the content of the dinaphthothiophene derivative in the composite particles, the greater the refractive index of the composition using the composite particles tends to be. Therefore, by adjusting the content of the dinaphthothiophene derivative according to the application, the refractive index of the transparent coating can be adjusted.

[0032] Next, we will provide a detailed explanation of compounds containing the dinaphthothiophene (DNT) skeleton, which are dinaphthothiophene derivatives (hereinafter referred to as "DNT compounds").

[0033] DNT compounds, whether alone or in mixtures with resins, exhibit extremely high refractive indices and can therefore be used as high refractive index optical materials. The DNT compound is preferably a compound represented by the following formula (1), or a polymer containing constituent units derived from this compound. [ka]

[0034] In equation (1), R 1Each of these is independently an organic group, a hydroxyl group, an amino group, a nitro group, a thiol group, a sulfo group, a halogen atom, or an optionally substituted silyl group, and R 2 Each of these is independently an organic group, a hydroxyl group, an amino group, a nitro group, a thiol group, a sulfo group, a halogen atom, or an optionally substituted silyl group, each of which is independently an integer between 0 and 2, and each of which is independently an integer between 0 and 4.

[0035] In equation (1), R 1 and R 2 Preferably, each is independently an organic group selected from the group consisting of a 2,3-epoxypropoxy group, a 2-(meth)acryloyloxyethoxy group, a (meth)acryloyloxymethoxy group, a RaO- group (where Ra is an alkyl group which may contain oxygen or sulfur), and an HO-Rb-O- group (where Rb is an alkylene group or aralkylene group which may contain oxygen or sulfur), or a hydroxyl group. Note that "(meth)acryloyl" is a general term for methacryloyl and acryloyl.

[0036] The DNT compound is preferably a compound represented by the following formula (2), or a polymer containing a constituent unit derived from this compound. [ka]

[0037] The content of the compound represented by formula (2) above or a polymer containing constituent units derived from this compound, relative to the total amount of the DNT compound, is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, and even more preferably 90% by mass or more. Having these compound and polymer content levels within this range tends to improve the refractive index of the resulting coating film.

[0038] DNT compounds and their crystals can be synthesized according to known methods. For example, the methods described in Japanese Patent Publication No. 2018-83774, Japanese Patent Publication No. 2014-196288, Japanese Patent Publication No. 2011-178985, Japanese Patent Publication No. 2017-137244, and Japanese Patent Publication No. 2015-30727 can be cited.

[0039] 1.2. Resin The resin may be used individually or in combination of two or more types. Such resins can be appropriately selected according to the application and are not particularly limited, but examples include polyimide, polyamide, various cellulose resins, poly(meth)acrylic acid esters, polystyrene, polyvinyl ether, polyolefin and copolymers of their constituent monomers, polycarbonate, polyester, polysulfide, polyurethane, polyether, phenolic resin, urea resin, melamine resin, epoxy resin, and oxetane resin.

[0040] Among these, polyimide resin is preferred. Using polyimide resin tends to result in even better transparency, heat resistance, and light resistance, as well as easier processing into optical materials and the like.

[0041] The resin in the composite particles may be composed of aggregated and bonded resin particles (hereinafter, these resin particles are referred to as "primary resin particles"). The average particle diameter of the primary resin particles is preferably 10 μm or less, more preferably 5.0 μm or less, and even more preferably 1.0 μm or less. The lower limit of the average particle diameter of the primary resin particles is not particularly limited, but may be, for example, 20 nm, 50 nm, or 100 nm.

[0042] In this embodiment, the average particle size of the primary resin particles is determined using a scanning electron microscope (SEM). Specifically, primary resin particles are imaged with an SEM, 10 particles are randomly selected from the multiple primary resin particles captured, and the average of the longitudinal lengths of these particles is taken as the average particle size of the primary resin particles. Specific conditions for the SEM can be those described in the examples.

[0043] The resin content in the composite particles is preferably 10% to 40% by mass, more preferably 15% to 35% by mass, and even more preferably 20% to 30% by mass, relative to the total mass of the composite particles. Having the resin content in the composite particles within this range tends to result in superior dispersion stability and viscosity when used as a varnish, as described later.

[0044] 1.3. Other ingredients The composite particles in this embodiment may contain other components as needed. These other components are not particularly limited, but examples include inorganic particles, which preferably have a refractive index of 1.8 or higher, more preferably 2.0 or higher, and even more preferably 2.2 or higher. Furthermore, the average particle diameter of the inorganic particles is preferably 100 nm or less, more preferably 50 nm or less, and even more preferably 30 nm or less. In particular, an average particle diameter of 100 nm or less tends to result in more transparent, harder composite particles and coatings. Such inorganic particles are not particularly limited, but examples include oxide particles such as titanium dioxide, zirconia, cerium oxide, zinc oxide, and tin oxide. The refractive index can be improved by including such inorganic particles in the composite particles.

[0045] The inorganic particle content in the composite particle can be appropriately selected according to the application and is not particularly limited, but for example, it may be 10% by mass or less, 5.0% by mass or less, or 3.0% by mass or less relative to the total mass of the composite particle. The lower limit of the inorganic particle content is not particularly limited, but for example, it may be 0% by mass.

[0046] 1.4. Manufacturing method One embodiment of the method for producing composite particles in this embodiment is a method that includes a grinding step in which a crystal of the dinaphthothiophene derivative and a resin are ground in a mill. In the production method of this embodiment, even if the crystal of the dinaphthothiophene derivative is ground, it can be made into composite particles while maintaining its crystal structure without becoming amorphous. Because the crystal structure of the raw material is maintained, the optical properties of the raw material crystal can be maintained even after being made into composite particles. Generally, it is known that the degree of crystallinity decreases when a crystal is ground (for example, Bulletin of the Faculty of Engineering, Hokkaido University, No. 102 (1981), pp. 55-66, and Japanese Patent Publication No. 2012-111841), so it is remarkable that composite particles can be made while maintaining the crystal structure.

[0047] Specific examples of dinaphthothiophene derivatives are as described above. The crystal shape of the dinaphthothiophene derivative before pulverization is preferably rod-shaped or needle-shaped.

[0048] Examples of mills used in the grinding process include ball mills, bead mills, and jet mills. Examples of ball mills include planetary ball mills and vibrating ball mills.

[0049] In the grinding process, either dry grinding or wet grinding may be employed. Dry grinding is a method of grinding in a gas such as air, in a vacuum, or in an inert gas. Wet grinding is a method of grinding in a liquid such as water. In this embodiment, the grinding process is preferably dry grinding, and more preferably a treatment in which high shear force and compressive force are applied during dry grinding (hereinafter referred to as "mechanochemical compounding treatment").

[0050] The grinding conditions are appropriately adjusted depending on the size and shape of the dinaphthothiophene derivative crystals used as raw materials and the desired composite particles.

[0051] (Dry grinding method using planetary ball mill) While not strictly limited, it is preferable to use a planetary ball mill when employing a dry grinding method. A planetary ball mill generates a large grinding force based on centrifugal force by rotating a grinding container filled with balls as the grinding medium, and then revolving it in the opposite direction to its rotation.

[0052] In a dry grinding method using a planetary ball mill, the material of the container wall and the balls is not particularly limited, but in order to minimize the incorporation of impurities due to wear of the container wall and the balls, it is preferable that the material of the container wall and the balls be the same. Examples of materials for the container wall and balls include agate, alumina, zirconia, tungsten carbide, chrome steel, and silicon nitride. From the viewpoint of wear resistance, agate, alumina, or zirconia are preferred for the container wall and balls.

[0053] In a dry grinding method using a planetary ball mill, the size of the balls is not particularly limited, but the diameter of the balls is preferably 1 mm to 15 mm, and more preferably 5 mm to 10 mm. By making the diameter of the balls 1 mm or more, the separation of the ground sample from the balls becomes easier. By making the diameter of the balls 15 mm or less, the grinding efficiency can be improved.

[0054] In a dry grinding method using a planetary ball mill, the packing rate of the dinaphthothiophene derivative crystals and balls together in the grinding container is preferably 10% by volume or more and 80% by volume or less, and more preferably 20% by volume or more and 70% by volume or less. By setting the packing rate to 10% by volume or more, direct collisions between balls and between balls and the inner wall of the container can be further suppressed, and wear of the balls and grinding container can be further reduced. By setting the packing rate to 80% by volume or less, grinding efficiency can be improved.

[0055] In a dry grinding method using a planetary ball mill, it is preferable to stop the operation as needed during the grinding process to allow for a cooling period in order to suppress the rise in temperature inside the container due to collisions and abrasion between the balls and between the balls and the inner wall of the container. During the stoppage, it is preferable to remove any sample adhering to the inner wall of the container and to break up any lumpy samples.

[0056] (Wet grinding method using a bead mill) While not particularly limited, it is preferable to use a bead mill when employing a wet grinding method. In a bead mill, beads as the grinding medium and a slurry containing the raw materials are placed in a grinding container, and a large grinding force can be obtained by the centrifugal force generated by rotating the agitator at high speed.

[0057] In a wet grinding method using a bead mill, the solvent (dispersion medium) used to disperse the dinaphthothiophene derivative, which is the raw material, is not particularly limited as long as it is a solvent in which the raw material is sparingly soluble or insoluble. Examples include water, or alcohols such as methanol, ethanol, isopropanol, glycerin, or propylene glycol. From the viewpoint of the environment and cost, it is preferable to use water.

[0058] In a wet grinding method using a bead mill, a surfactant may be added when water is used as the dispersion medium. The type of surfactant is not particularly limited as long as it has the effect of suppressing particle aggregation during the grinding process. Examples of surfactants include nonionic surfactants, amphoteric surfactants, cationic surfactants, and anionic surfactants.

[0059] In a wet grinding method using a bead mill, the material of the inner wall of the container and the beads is not particularly limited, but in order to minimize the introduction of impurities due to wear of the inner wall of the container and the beads, it is preferable that the material of the inner wall of the container and the beads be the same. Examples of materials for the inner wall of the container and the beads include alumina, zirconia, tungsten carbide, glass, chrome steel, and silicon nitride. From the viewpoint of wear resistance, the inner wall of the container and the beads made of zirconia are preferred.

[0060] In a wet grinding method using a bead mill, the size of the beads is not particularly limited, but the diameter of the beads is preferably 0.03 mm or more and 2 mm or less, and more preferably 0.1 mm or more and 0.8 mm or less. By setting the diameter of the beads to 0.03 mm or more, the separation of the ground sample from the beads becomes even easier. By setting the diameter of the beads to 2 mm or less, the efficiency of generating nanofiber crystals of the dinaphthothiophene derivative can be improved.

[0061] In a wet grinding method using a bead mill, the solid content concentration in the slurry is preferably 0.5% by mass or more and 30% by mass or less, more preferably 1% by mass or more and 10% by mass or less. By setting the solid content concentration to 0.5% by mass or more, direct collisions between beads and between beads and the inner wall of the container can be further suppressed, thereby reducing wear on the beads and the grinding container. By setting the solid content concentration to 30% by mass or less, the fluidity of the slurry can be better maintained, and the grinding efficiency can be improved.

[0062] In a wet grinding method using a bead mill, the bead filling rate in the grinding container is preferably 50% by volume or more and 95% by volume or less, and more preferably 70% by volume or more and 90% by volume or less. By setting the filling rate to 50% by volume or more, the efficiency of generating nanofiber crystals of the dinaphthothiophene derivative can be improved. By setting the filling rate to 95% by volume or less, wear of the beads and the grinding container can be further suppressed.

[0063] In a wet grinding method using a bead mill, the peripheral speed of the stirring mechanism is preferably 6.0 m / s to 15 m / s, and more preferably 8.0 m / s to 12 m / s. By setting the peripheral speed to 6.0 m / s or higher, the efficiency of nanofiber crystal formation can be improved. By setting the peripheral speed to 15 m / s or lower, wear on the beads and grinding container can be further suppressed.

[0064] In a wet grinding method using a bead mill, the slurry temperature can be controlled by adjusting the cooling water temperature, circulation speed, peripheral speed, etc. The slurry temperature at the outlet of the grinding container is preferably 10°C to 30°C, and more preferably 15°C to 25°C. By keeping the slurry temperature above 10°C, the amount of cooling water required can be further reduced, and temperature control becomes easier. By keeping the slurry temperature below 30°C, wear on the beads and grinding container can be further suppressed.

[0065] In a wet grinding method using a bead mill, the operating method is not particularly limited and examples include batch type, pass type, and circulating type. From the viewpoint of temperature control and work efficiency, the circulating type operating method is preferred.

[0066] 2. Varnish The varnish in this embodiment comprises the composite particles and solvent of this embodiment, or comprises a dinaphthothiophene derivative, resin and solvent, and may optionally contain other components.

[0067] 2.1. Solvent The solvent in this embodiment is preferably one that is difficult to dissolve the dinaphthothiophene derivative and can dissolve the resin, and one or more solvents can be selected depending on the application.

[0068] Such solvents are not particularly limited, but examples include aromatic solvents such as toluene and xylene; ether solvents such as tetrahydrofuran and diphenyl ether; amide solvents such as dimethylformamide and dimethylacetamide; hydrocarbon solvents such as cyclohexane and decalin; ketotic solvents such as methyl ethyl ketone and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; nitrile solvents such as acetonitrile and butyronitrile; sulfur solvents such as carbon disulfide and dimethyl sulfoxide; and halogen solvents such as chloroform, dichloroethane, and trichloroethane.

[0069] The solvent content in the above varnish is preferably 50% to 95% by mass, more preferably 65% ​​to 85% by mass, and even more preferably 70% to 80% by mass, based on the total mass of the varnish. By having the solvent content in the varnish within this range, an even thinner and more uniform coating film can be produced.

[0070] The varnish of this embodiment may contain, for example, inorganic nanoparticles as other components, although this is not particularly limited. Such inorganic particles preferably have a refractive index of 1.8 or higher, more preferably 2.0 or higher, and even more preferably 2.2 or higher. The average particle diameter of the inorganic particles is preferably 100 nm or less, more preferably 50 nm or less, and even more preferably 30 nm or less. In particular, an average particle diameter of 100 nm or less tends to make it easier to obtain a more transparent and hard coating film. Such inorganic particles are not particularly limited, but examples include oxide nanoparticles such as titanium dioxide, zirconia, cerium oxide, zinc oxide, and tin oxide. The inclusion of such inorganic particles in the varnish tends to improve the refractive index of the coating film.

[0071] 2.2. Manufacturing method When preparing a varnish containing particles of the dinaphthothiophene derivative according to this embodiment, the composite particles of this embodiment can be added to a solvent that is difficult to dissolve the dinaphthothiophene derivative but capable of dissolving the resin particles.

[0072] Furthermore, to prepare a varnish containing the dinaphthothiophene derivative of this embodiment but without its particles, the dinaphthothiophene derivative, resin, and other components as needed are added to a solvent capable of dissolving the dinaphthothiophene derivative and resin, and the mixture is stirred or otherwise disposed of.

[0073] To rapidly disperse the composite particles or dinaphthothiophene derivative in the solvent, known apparatus may be used as needed. Such apparatus is not particularly limited, but examples include ultrasonic cleaners.

[0074] By using the composite particles and varnish of this embodiment, transparent coatings (especially transparent and hard coatings) and other transparent, hard molded articles can be produced. Furthermore, such composite particles and varnish can also be used as adhesives for bonding materials together.

[0075] More specifically, by simply heating the composite particles of this embodiment in their solid state, a dry coating can be created on the surface of an object, and it can be used for bonding two or more materials. For example, by creating a thin, uniform powder layer made of the composite particles of this embodiment on the surface of a glass plate and then heating it at an appropriate temperature and time, a transparent and hard coating can be created on the surface of the glass plate. Also, by heating a powder layer of composite particles sandwiched between two glass plates, the powder layer changes into a transparent material, and at the same time, the two glass plates can be bonded together.

[0076] Furthermore, it is possible to use all or part of the composite particles of this embodiment by dissolving them in a solvent. Specifically, the varnish of this embodiment can be used as a coating agent or adhesive. For example, by applying the varnish of this embodiment to the surface of a glass plate to create a thin, uniform coating layer, and then volatilizing the organic solvent in the varnish, a transparent coating film can be created on the surface of the glass plate. Alternatively, the varnish can be sandwiched between two glass plates, and the organic solvent in the varnish can be volatilized to bond the two glass plates together.

[0077] Since the refractive index of the resulting coating film is correlated with the content of the dinaphthothiophene derivative in the composite particles or varnish, it is possible to control the refractive index of the resulting hard coating film by adjusting the content of the dinaphthothiophene derivative in the composite particles or varnish. [Examples]

[0078] The present invention will be described more specifically below using examples and comparative examples. The present invention is not limited in any way by the following examples.

[0079] 1. Measurement conditions <Conditions for Nuclear Magnetic Resonance (NMR)> The measurement was performed using an NMR spectrometer manufactured by JEOL Ltd. (product name: JNM-ECA600), with dimethyl sulfoxide-d6 (DMSO-d6) as the solvent and the residual H signal of the measurement solvent (2.49 ppm) as the standard substance.

[0080] <Conditions for Scanning Electron Microscope (SEM)> Analytical instrument: Scanning electron microscope manufactured by JEOL Ltd. (Product name: JSM-6610LA) Acceleration voltage: 20kV Pretreatment, etc.: The sample was fixed onto carbon tape and gold deposition was performed.

[0081] <Conditions for powder X-ray diffraction (XRD) measurement> Measurement device: Powder X-ray diffractometer manufactured by Rigaku Corporation (product name: RINT) X-ray:Cu / 40kV / 30mA Counting time / scan speed: 2 deg / min Goniometer: Ultima+ Horizontal Goniometer Sampling width: 0.02 deg Scan axis: 2θ / θ Scanning range: 5-80 degrees Long side limiting slit: 10mm Entrance slit: 1° Light-receiving slit 1:1° Light-receiving slit 2: 0.3 mm Detector: Scintillation counter Scan mode: Continuous

[0082] <Conditions for Differential Scanning Calorimetry (DSC)> Measurement device: Differential scanning calorimeter manufactured by Seiko Instruments Inc. (Product name: DSC6200) Reference: Al (container only) Heating rate: 10℃ / min Gas: N2 Gas flow rate: 50 mL / min

[0083] <Conditions for Mechanochemical Compounding Treatment> Equipment used: Planetary ball mill (Product name: premium-line P-7, manufactured by Fritsch Japan Co., Ltd.) Container used: Volume; 80mL, Type: Zirconia Compounding process: 10g of the mixed powder was placed in the above container together with 80g of zirconia with a diameter of 5mm, and the mixture was ground at a rotation speed of 600rpm for a total rotation time of 45 minutes. In order to suppress the rise in temperature inside the container due to friction, the process was repeated with a 60-minute interval between each 5-minute rotation, until the total rotation time reached 45 minutes.

[0084] 2. Preparation of dinaphthothiophene derivatives Dinaphthothiophene (DNT) was synthesized based on the method described in Example 1 of Japanese Patent Publication No. 2011-178985.

[0085] Furthermore, based on the methods described in Examples 2, 3, and 7 of Japanese Patent Publication No. 2011-178985, a methacrylate monomer (DNTMA) having a dinaphthothiophene skeleton was synthesized, and a 100% pure white powder was obtained. [ka]

[0086] The results of the NMR measurement of DNTMA are as follows: 1H NMR (DMSO-d6, 600MHz): δ(ppm) 1.94(3H,s), 5.63(2H,s), 5.75(1H,s), 6.15(1H,s), 7.63-7.67(4H,m), 8 .10-8.11(1H,d), 8.16-8.19(3H,m), 8.23-8.24(1H,d), 8.69-8.73(2H,m)

[0087] 3. Fabrication of composite particles <Example 1: Composite Particle 1> A mixture of the following composition was placed in a mortar, ground and mixed for approximately 5 minutes to produce a mixed powder, which was then subjected to the above-described mechanochemical compounding treatment to obtain composite particle 1. [Mixing ratio (mass%)] DNTMA: 64.3% DNT: 7.1% Polyimide resin (product number: KPI-MX300F, manufactured by Kawamura Sangyo Co., Ltd.): 28.6%

[0088] <Example 2: Composite Particle 2> A mixture of the following composition was placed in a mortar, ground and mixed for approximately 5 minutes to produce a mixed powder, which was then subjected to the above-described mechanochemical compounding treatment to obtain composite particles 2. [Mixing ratio (mass%)] DNTMA: 64.3% DNT: 7.1% Ethylcellulose (product number 14076-01, Grade 1, manufactured by Kanto Chemical Co., Ltd.): 28.6%

[0089] <Comparative Example 1 and Example 3: Mixed Powder 1 and Composite Particles 3> A mixture of the following composition was placed in a mortar and ground and mixed for approximately 5 minutes to obtain mixed powder 1. A portion of the mixed powder 1 was subjected to the above-mentioned mechanochemical compounding treatment to obtain composite particles 3. [Mixing ratio (mass%)] DNTMA: 50% Ethylcellulose (product number 14076-01, Grade 1, manufactured by Kanto Chemical Co., Ltd.): 50%

[0090] 4. Making the varnish <Example 4: Varnish 1> After placing 1 g of composite particles 1 prepared in Example 1 into a 9 mL glass vial, 3.5 mL of THF was added as a solvent, and the lid of the glass vial was closed. Then, using a tabletop ultrasonic cleaner (W-170ST, manufactured by Honda Electronics Co., Ltd.), the solvent and composite particles in the glass vial were stirred, and this process of stirring for 10 minutes, followed by a 60-minute interval, was repeated six times, for a total of 60 minutes of stirring to obtain a transparent varnish 1.

[0091] <Example 5: Varnish 2> A transparent varnish 2 was obtained in the same manner as in Example 4, except that the composite particles were changed from composite particle 1 to composite particle 2 prepared in Example 2.

[0092] <Example 6: Varnish 3> A transparent varnish 3 was obtained in the same manner as in Example 4, except that the composite particles were changed from composite particle 1 to composite particle 3 prepared in Example 3.

[0093] 5. Rating <Composite particle 1> Figures 2, 3, and 4 show the scanning electron microscope image, powder X-ray diffraction profile, and investigative scanning calorimetry profile of composite particles 1 obtained by the above mechanochemical composite treatment. Figure 5 shows the investigative scanning calorimetry profile of the mixed powder before the production of composite particles 1.

[0094] Observations using a scanning electron microscope, as shown in Figure 2, revealed that composite particle 1 is in a state where the dinaphthothiophene derivative and resin are uniformly interwoven.

[0095] As shown in Figure 3, when comparing the X-ray diffraction measurement profiles of composite particle 1 and the mixed powder before composite formation (the mixed powder profile is not shown), the peak intensities in the X-ray diffraction measurement profile of composite particle 1 decreased, but the peak shapes and positions of each peak were almost identical. This indicates that the dinaphthothiophene derivative particles in composite particle 1 retain their crystalline properties even after being formed into composite particles.

[0096] Furthermore, the results of the investigative scanning calorimetry profile shown in Figure 4 indicate that the endothermic and heat-releasing peaks of composite particle 1 are shifted to lower temperatures compared to the investigative scanning calorimetry profile of the mixed powder shown in Figure 5. In addition, the heat quantities at the endothermic and heat-releasing peaks have also changed, indicating that composite particle 1 has different thermophysical properties compared to the mixed powder before composite formation.

[0097] <Composite particles 2> Figures 6, 7, and 8 show the scanning electron microscope image, powder X-ray diffraction profile, and investigative scanning calorimetry profile of the composite particles 2 obtained by the above mechanochemical composite treatment. Figure 9 shows the investigative scanning calorimetry profile of the mixed powder before the production of composite particles 2. Observations using a scanning electron microscope, as shown in Figure 6, revealed that composite particle 2 is in a state where the dinaphthothiophene derivative and resin are uniformly interwoven.

[0098] As shown in Figure 7, when comparing the X-ray diffraction measurement profiles of composite particle 2 and the mixed powder before composite formation (the mixed powder profile is not shown), the peak intensities in the X-ray diffraction measurement profile of composite particle 2 decreased, but the peak shapes and positions of each peak were almost identical. This indicates that the dinaphthothiophene derivative particles in composite particle 2 retain their crystalline properties even after being formed into composite particles.

[0099] Furthermore, the results of the investigative scanning calorimetry profile shown in Figure 8 indicate that the endothermic and heat-releasing peaks of composite particle 2 are shifted to lower temperatures compared to the investigative scanning calorimetry profile of the mixed powder shown in Figure 9. In addition, the heat quantities at the endothermic and heat-releasing peaks have also changed, indicating that the composite particles have different thermophysical properties compared to the mixed powder before composite formation.

[0100] <Composite particles 3 and mixed powder 1> Scanning electron microscope images of the prepared mixed powder 1 and composite particles 3 are shown in Figures 10 and 11, respectively. In mixed powder 1 shown in Figure 10, the dinaphthothiophene derivative particles and resin particles are separated and do not intermingle, whereas in composite particles 3 shown in Figure 11, the dinaphthothiophene derivative and resin are uniformly intermingled.

[0101] <Varnish 1> Using a film applicator (slide glass size, manufactured by Allgood), varnish 1 from Example 4 was applied to the surface of a slide glass, and then left for one day under atmospheric conditions to obtain a transparent and hard coating on the slide glass surface. The refractive index and extinction coefficient of the obtained coating were measured using a high-speed spectroscopic ellipsometer M-2000V-Te (manufactured by JAWoollam Co.).

[0102] Figure 12 shows the refractive index n and extinction coefficient k of the coating obtained using varnish 1, with wavelength on the horizontal axis. As an example of the profile shown in Figure 12, the refractive index at a wavelength of 589.5 nm was 1.68. As shown in Figure 12, it was found that a coating with excellent refractive index and transmittance can be obtained by using varnish 1.

[0103] <Varnish 2> Similarly, using varnish 2 from Example 5, a transparent and hard coating was obtained on the glass slide surface by the same procedure as with varnish 1. Then, the refractive index and extinction coefficient of the obtained coating were measured using a high-speed spectroscopic ellipsometer M-2000V-Te (manufactured by JAWoollam Co.).

[0104] Figure 13 shows the refractive index n and extinction coefficient k of the coating obtained using varnish 2, with wavelength on the horizontal axis. As an example of the profile shown in Figure 13, the refractive index at a wavelength of 589.5 nm was 1.65. As shown in Figure 13, it was found that a hard coating with excellent refractive index and transmittance can be obtained by using varnish 2.

[0105] <Varnish 3> Similarly, using varnish 3 from Example 6, a transparent and hard coating was obtained on the glass slide surface by the same procedure as with varnish 1. The refractive index of the obtained coating was then measured using a high-speed spectroscopic ellipsometer M-2000V-Te (manufactured by JAWoollam Co.).

[0106] The coating obtained using varnish 3 had a refractive index of 1.59 at a wavelength of 589.5 nm. [Industrial applicability]

[0107] The composite particles and varnish of the present invention can be used to produce transparent, hard coatings and other transparent, hard molded articles. Furthermore, the composite particles and varnish of the present invention can also be used for bonding materials together. Therefore, the composite particles and varnish of the present invention have industrial applicability in these applications. [Explanation of Symbols]

[0108] 1...Composite particles, 11...Dinaphthothiophene derivative nanofibers, 12...Resin particles.

Claims

1. The compound comprises a compound having a dinaphthothiophene skeleton and a resin. The compound includes a compound having a nanofiber-like dinaphthothiophene skeleton, The content of the aforementioned compound is 50% by mass or more and 90% by mass or less, relative to the total mass of the composite particles. composite particles.

2. The average particle diameter of the composite particles is 1 μm or more. The composite particle according to claim 1.

3. The composite particle according to claim 1, wherein the thickness of the compound is 1 μm or less.

4. The compound is a compound represented by the following formula (1), or a polymer containing a structural unit derived from the compound represented by the following formula (1). The composite particle according to any one of claims 1 to 3. 【Chemistry 1】 (In the formula, R 1 Each of these is independently an organic group, a hydroxyl group, an amino group, a nitro group, a thiol group, a sulfo group, a halogen atom, or an optionally substituted silyl group, R 2 Each of these is independently an organic group, a hydroxyl group, an amino group, a nitro group, a thiol group, a sulfo group, a halogen atom, or an optionally substituted silyl group; each of these is independently an integer from 0 to 2; and each of these is independently an integer from 0 to 4.

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