Titanium Oxide Particles, Resin Composition for Electronic Materials, Molded Article, Member for Electronic Equipment, and Method for Producing Titanium Oxide Particles

Abstract

Titanium oxide particles containing titanium dioxide, wherein the average crystallite size determined from the peak at 2θ = 27.5° ± 1.0° obtained by X-ray diffraction measurement of the titanium dioxide is 220 nm or more. A production method of titanium oxide particles, comprising: a mixing step of mixing a titanium compound, a molybdenum compound, and a potassium compound and / or a sodium compound to form a mixture; and a firing step of firing the mixture, wherein the molar ratio of Mo / M1 (wherein M1 represents Na and K) in the mixture is more than 0.5.

Description

Technical Field

[0001] The present invention relates to titanium oxide particles, a resin composition for electronic materials, a molded product, a member for electronic devices, and a method for producing the titanium oxide particles.

Background Art

[0002] Titanium oxide particles are widely used in various fields such as inks, resin fillers, catalysts, catalyst carriers, adsorbents, photocatalysts, antibacterial agents, optical materials, cosmetic ingredients, pigments, paints, fillers, and electronic materials. Patent Document 1 discloses rutile-type titanium oxide particles containing molybdenum, wherein the average particle diameter of the titanium oxide particles is 0.1 to 100 μm.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when attempting to apply titanium oxide particles by taking advantage of their dielectric properties, there is still room for improvement in reducing the dielectric loss tangent of the titanium oxide particles.

[0005] The present invention has been made to solve the above problems, and an object thereof is to provide titanium oxide particles with a reduced dielectric loss tangent.

Means for Solving the Problems

[0006] (1) Titanium oxide particles containing titanium dioxide, wherein the average crystallite size determined from the peak at 2θ = 27.5° ± 1.0° obtained by X-ray diffraction measurement of the titanium dioxide is 220 nm or more. (2) The titanium oxide particles according to (1) above, wherein the average particle diameter of the titanium oxide particles is 0.1 to 300 μm. (3) The titanium oxide particles according to (1) or (2) above, which contain molybdenum. (4) The titanium oxide particles according to any one of (1) to (3) above, wherein the titanium dioxide contains rutile-type titanium dioxide. (5) The titanium oxide particles according to any one of (1) to (4) above, wherein the dielectric tangent at 1 GHz is 0.0040 or less. (6) The titanium oxide particles according to any one of (1) to (5) above, which are for electronic materials. (7) A resin composition for electronic materials, which contains a resin and the titanium oxide particles according to any one of (1) to (6) above. (8) A molded product of the resin composition for electronic materials according to (7) above. (9) A member for electronic equipment, which contains the titanium oxide particles according to any one of (1) to (6) above. (10) A method for producing the titanium oxide particles according to any one of (1) to (6) above, which includes a mixing step of mixing a titanium compound, a molybdenum compound, and a potassium compound and / or a sodium compound to form a mixture, and a firing step of firing the mixture. A method for producing titanium oxide particles, wherein the molar ratio of Mo / M1 (where M1 represents Na and K) in the mixture is more than 0.5. (11) The mixing step is a step of mixing a titanium compound and a compound containing molybdenum and potassium, or a compound containing molybdenum and sodium, to form a mixture. The compound containing molybdenum and potassium is K2Mo2O7. The method for producing titanium oxide particles according to (10) above, wherein the compound containing molybdenum and sodium is Na2Mo2O7. (12) The method for producing titanium oxide particles according to (10) or (11) above, wherein the firing step fires the mixture under the conditions of a firing temperature of 1200 to 1350 °C and a firing temperature holding time of 15 to 30 hours.

Advantages of the Invention

[0007] According to the present invention, titanium oxide particles with a reduced dielectric loss tangent can be provided.

Brief Description of the Drawings

[0008]

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Modes for Carrying Out the Invention

[0009] Hereinafter, embodiments of the titanium oxide particles, resin compositions for electronic materials, molded articles, members for electronic devices, and methods for producing titanium oxide particles of the present invention will be described.

[0010] ≪Titanium Oxide Particles≫ The titanium oxide particles of the embodiment contain titanium dioxide, and the average crystallite size of the titanium dioxide determined from the peak at 2θ = 27.5° ± 1.0° obtained by X-ray diffraction measurement is 220 nm or more.

[0011] The average crystallite size of titanium dioxide contained in the titanium oxide particles, determined from the peak at 2θ = 27.5° ± 1.0° obtained by X-ray diffraction measurement, is 220 nm or more, preferably 250 nm or more, more preferably 300 nm or more, still more preferably 350 nm or more, yet more preferably 400 nm or more, and particularly preferably 500 nm or more. By including titanium dioxide having an average crystallite size of the above lower limit or more, the value of the dielectric tangent of the titanium oxide particles is reduced.

[0012] The upper limit of the average crystallite size of the titanium dioxide, determined from the peak at 2θ = 27.5° ± 1.0° obtained by X-ray diffraction measurement, may be, for example, 1000 nm or less, may be 800 nm or less, may be 700 nm or less, may be 650 nm or less, or may be 600 nm or less.

[0013] As an example of the numerical range of the above numerical values of the average crystallite size of the titanium dioxide, determined from the peak at 2θ = 27.5° ± 1.0° obtained by X-ray diffraction measurement, it may be 220 nm or more and 1000 nm or less, may be 250 nm or more and 1000 nm or less, may be 300 nm or more and 800 nm or less, may be 350 nm or more and 700 nm or less, may be 400 nm or more and 650 nm or less, or may be 500 nm or more and 600 nm or less.

[0014] The above average crystallite size in the titanium oxide particles of the embodiment can be specified by the following measurement method.

[0015] [Measurement of Crystallite Size] Using an X-ray diffractometer (for example, SmartLab, manufactured by Rigaku Corporation), using an ultra-high resolution spiral analyzer (CALSA) as a detector, and using PDXL2 as analysis software, the measurement is performed. The measurement method is the 2θ / θ method, and the average crystallite size of titanium dioxide is calculated using the Scherrer equation from the half-width of the peak that appears at 2θ = 27.5° ± 1.0° under the following measurement conditions. [Measurement Conditions] Scan range: 2θ = 10 to 70° Step: 2θ = 0.002° Speed: 2θ = 0.05° / min βs = 20 rpm Soller / PSC: 2θ = 2.5° short Soller: 2θ = 2.5° Analysis software: PDXL2 Device inherent width: None Peak shape: Automatically analyzed using the CALSA function

[0016] The titanium oxide particles of the embodiment contain titanium dioxide (TiO2). The titanium oxide particles of the embodiment preferably contain 50% by mass or more of titanium dioxide (TiO2) based on the total mass (100% by mass) of the titanium oxide particles, more preferably 50 to 99.9% by mass, still more preferably 80 to 99.9% by mass, and even more preferably 90 to 99.8% by mass.

[0017] The content of titanium dioxide (TiO2) in the titanium oxide particles of the embodiment may be a value calculated by the following XRF analysis.

[0018] The titanium content in the titanium oxide particles of the embodiment may be such that the content rate in terms of TiO2 conversion with respect to 100% by mass of the total mass of the titanium oxide particles, which is determined by subjecting the titanium oxide particles to XRF analysis, is 50% by mass or more, may be 50 to 99.9% by mass, may be 80 to 99.9% by mass, or may be 90 to 99.8% by mass.

[0019] The content rate in terms of TiO2 conversion means a value obtained from the amount of TiO2 obtained by converting the titanium content determined by subjecting the titanium oxide particles to XRF analysis using a calibration curve in terms of TiO2 conversion.

[0020] The titanium oxide particles of the embodiment may contain molybdenum. The titanium oxide particles of the embodiment can contain molybdenum derived from a molybdenum compound that may be used in the production method described later.

[0021] The existing state and amount of molybdenum that may be contained in the titanium oxide particles of the embodiment are not particularly limited. In addition to molybdenum metal, molybdenum oxide, molybdenum compounds in which a part has been reduced, etc. may be contained in the titanium oxide particles. Molybdenum is considered to be contained in the titanium oxide particles as MoO3, but in addition to MoO3, it may also be contained in the titanium oxide particles as MoO2, MoO, etc.

[0022] The form of molybdenum content is not particularly limited, and it may be contained in a form attached to the surface of the titanium oxide particles, in a form substituted for a part of the crystal structure of the titanium oxide particles, in an amorphous state, or a combination thereof.

[0023] The molybdenum content in the titanium oxide particles of the embodiment may be such that the content rate in terms of MoO3 conversion with respect to 100% by mass of the total mass of the titanium oxide particles, which is determined by XRF analysis of the titanium oxide particles, is 0.01% by mass or more, may be 0.01 to 25% by mass, may be 0.05 to 10% by mass, or may be 0.1 to 5% by mass.

[0024] The content rate in terms of MoO3 conversion refers to a value obtained from the amount of MoO3 obtained by converting the molybdenum content determined by XRF analysis of the titanium oxide particles using a calibration curve in terms of MoO3 conversion.

[0025] The titanium oxide particles of the embodiment may contain potassium and / or sodium. The titanium oxide particles of the embodiment can contain potassium and / or sodium derived from a potassium compound and / or a sodium compound that may be used in the production method described later.

[0026] The potassium and / or sodium content in the titanium oxide particles may be such that the total content rate in terms of K2O conversion and Na2O conversion with respect to 100% by mass of the total mass of the titanium oxide particles, which is determined by XRF analysis of the titanium oxide particles, is 5% by mass or less, or may be 0.01 to 5% by mass.

[0027] The total content in terms of K2O conversion and Na2O conversion refers to the value obtained from the sum of the amount of K2O obtained by converting the potassium content determined by XRF analysis of the titanium oxide particles using a calibration curve for K2O conversion and the amount of Na2O obtained by converting the sodium content determined by XRF analysis using a calibration curve for Na2O conversion. Note that the potassium content and / or sodium content in the titanium oxide particles may be 0.

[0028] The values of the titanium content, molybdenum content, and potassium and / or sodium content in the titanium oxide particles can be freely combined.

[0029] As an example of the titanium oxide particles of the embodiment, titanium oxide particles can be exemplified in which the content rate in terms of TiO2 of titanium with respect to 100% by mass of the total mass of the titanium oxide particles determined by XRF analysis is 50 to 99.9% by mass, and the content rate in terms of MoO3 of molybdenum is 0.01 to 25% by mass.

[0030] As an example of the titanium oxide particles of the embodiment, titanium oxide particles can be exemplified in which the content rate in terms of TiO2 of titanium with respect to 100% by mass of the total mass of the titanium oxide particles determined by XRF analysis is 50 to 99.9% by mass, the content rate in terms of MoO3 of molybdenum is 0.01 to 25% by mass, and the total content rate in terms of K2O conversion and Na2O conversion of potassium and / or sodium is 0.01 to 5% by mass.

[0031] The average particle diameter of the titanium oxide particles of the embodiment may be 0.1 μm or more, may be 0.5 μm or more, may be 5 μm or more, or may be 50 μm or more. Titanium oxide particles having an average particle diameter of the above lower limit value or more are easy to handle and have excellent resin filling properties when contained in a resin composition, and can be easily filled at a high density in the resin composition.

[0032] The average particle diameter of the titanium oxide particles may be 300 μm or less, may be 250 μm or less, may be 200 μm or less, and may be 150 μm or less. Titanium oxide particles having an average particle diameter equal to or less than the above upper limit value can easily obtain a molded product with excellent surface smoothness.

[0033] As an example of the numerical range of the above values of the average particle diameter of the titanium oxide particles, it may be 0.1 μm or more and 300 μm or less, may be 0.5 μm or more and 250 μm or less, may be 5 μm or more and 200 μm or less, and may be 50 μm or more and 150 μm or less.

[0034] In this specification, the average particle diameter of titanium oxide particles means that titanium oxide particles are photographed with a scanning electron microscope (SEM), and for the titanium oxide particles confirmed on the two-dimensional image, among the distances between two points on the contour line of the primary particles of 50 or more randomly selected titanium oxide particles, the maximum length is taken as the particle diameter, and its average value is adopted.

[0035] For the particle diameter of the titanium oxide particles measured as described above, the value calculated by standard deviation / average particle diameter × 100 is preferably 30% or less, preferably 2 - 30%, more preferably 5 - 25%, and even more preferably 10 - 25%. Titanium oxide particles satisfying the above numerical range of standard deviation / average particle diameter × 100 are even more excellent in resin filling property when contained in a resin composition.

[0036] The median diameter D of the titanium oxide particles of the embodiment 50 may be 0.1 μm or more and 300 μm or less, may be 0.5 μm or more and 200 μm or less, and may be 50 μm or more and 150 μm or less.

[0037] For the median diameter D50 of the titanium oxide particles of the embodiment, using a laser diffraction dry particle size distribution analyzer (for example, HELOS (H3355)&RODOS manufactured by Nippon Laser Co., Ltd.), under the conditions of a dispersion pressure of 3 bar and a suction pressure of 90 mbar, the particle size distribution of the sample powder is measured dry, and the particle size at the point where the distribution curve of volume integration % intersects the horizontal axis of 50% is taken as D 50 and obtained as such.

[0038] The crystal structure of titanium dioxide contained in the titanium oxide particles of the embodiment can be specified by the XRD pattern of the spectrum obtained in the XRD analysis.

[0039] As the crystal structure of titanium dioxide, there are anatase type, rutile type, and brookite type. It is preferable that the titanium oxide particles of the embodiment contain rutile type titanium dioxide. The rutile crystallization rate of the titanium dioxide is preferably 90% or more. Titanium oxide particles containing rutile type titanium dioxide have a higher relative permittivity compared to titanium dioxide particles with other crystal structures, and can easily miniaturize the millimeter wave (for example, wavelength: 4 - 12 mm, frequency: 24 - 71 GHz, etc.) antenna substrate for the fifth generation mobile communication system (5G).

[0040] According to the manufacturing method of the embodiment described later, it is excellent in shape control according to the crystal shape of the composition of the manufactured titanium oxide particles. The crystal shape of the titanium oxide particles of the embodiment is controlled and can have a polyhedral shape or an idiomorphic shape such as a substantially spherical shape. As the shape, it may be a polyhedron that is substantially spherical with a flat surface, or a substantially spherical shape with a smooth spherical surface. Titanium oxide particles having these shapes can be manufactured by the manufacturing method described later.

[0041] The dielectric loss tangent of the titanium oxide particles of the embodiment is reduced. The dielectric loss tangent of the titanium oxide particles of the embodiment may be 0.0040 or less, 0.0025 or less, 0.0010 or less, or 0.0008 or less at 1 GHz.

[0042] The titanium oxide particles of the embodiment may have a relative permittivity at 1 GHz of 51 to 160, may be 53 to 150, or may be 65 to 120.

[0043] For the dielectric loss tangent and relative permittivity of the titanium oxide particles of the embodiment, the sample powder filled in the measurement tube is set in a cavity resonator (for example, CP-001-PW, manufactured by EM Lab), and the complex relative permittivity of the mixture of the sample powder and air at 1 GHz is measured under the measurement conditions of a temperature of 25°C using a vector network analyzer (for example, P9373A, manufactured by Keysight). Then, using Lichtenecker's rule, from the measured complex relative permittivity, the volume fraction of the sample powder, and the complex relative permittivity of air, the relative permittivity (ε r ) and dielectric loss tangent (tanδ) of the sample powder are calculated.

[0044] The titanium oxide particles of the embodiment can be suitably used as a resin filler contained in a resin composition. The titanium oxide particles of the embodiment can be used as a dielectric.

[0045] Since the dielectric loss tangent of the titanium oxide particles of the embodiment is reduced, they can be suitably used as titanium oxide particles for electronic materials. As used herein, "for electronic materials" means that the titanium oxide particles are used in applications where they are contained in at least a part of an electronic device or a member constituting the electronic device. The electronic device is preferably a communication device, and more preferably a communication device for high-frequency applications.

[0046] The titanium oxide particles of the embodiment can be suitably used as a filler for electronic materials contained in a composition for constituting an electronic device or a member of an electronic device. As the composition, a resin composition is preferable. The titanium oxide particles of the embodiment can be suitably used as a filler for electronic materials contained in a resin composition for constituting an electronic device or a member of an electronic device.

[0047] As one embodiment of the present invention, there is provided a resin composition for electronic materials containing a resin and titanium oxide particles, wherein the titanium oxide particles contain titanium dioxide, and the average crystallite size of the titanium dioxide determined from the peak at 2θ = 27.5° ± 1.0° obtained by X-ray diffraction measurement is 220 nm or more.

[0048] Examples of the titanium oxide particles contained in the resin composition for electronic materials can be the same as those exemplified as the titanium oxide particles in the above embodiment.

[0049] The resin contained in the resin composition for electronic materials is not particularly limited, and for example, a thermosetting resin or a thermoplastic resin can be used.

[0050] In this specification, a thermosetting resin is a resin having a property that it can be substantially insolubilized and infusibilized when cured by heating or means such as radiation or a catalyst. Specific examples thereof include epoxy resins, phenolic resins, urea resins, melamine resins, benzoguanamine resins, alkyd resins, unsaturated polyester resins, vinyl ester resins, diallyl terephthalate resins, silicone resins, urethane resins, furan resins, ketone resins, xylene resins, thermosetting polyimide resins, benzoxazine resins, active ester resins, aniline resins, cyanate ester resins, styrene maleic anhydride (SMA) resins, maleimide resins, and the like. These thermosetting resins can be used alone or in combination of two or more.

[0051] In this specification, a thermoplastic resin refers to a resin that can be melt-molded by heating. Specific examples thereof include polyethylene resin, polypropylene resin, polystyrene resin, rubber-modified polystyrene resin, acrylonitrile-butadiene-styrene (ABS) resin, acrylonitrile-styrene (AS) resin, polymethyl methacrylate resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyethylene terephthalate resin, ethylene vinyl alcohol resin, cellulose acetate resin, ionomer resin, polyacrylonitrile resin, polyamide resin, polyacetal resin, polybutylene terephthalate resin, polylactic acid resin, polyphenylene ether resin, modified polyphenylene ether resin, polycarbonate resin, polysulfone resin, polyphenylene sulfide resin, polyetherimide resin, polyethersulfone resin, polyarylate resin, thermoplastic polyimide resin, polyamideimide resin, polyetheretherketone resin, polyketone resin, liquid crystal polyester resin, fluororesin, syndiotactic polystyrene resin, cyclic polyolefin resin, and the like. These thermoplastic resins can be used alone or in combination of two or more.

[0052] The resin composition for electronic materials may have other formulations. For example, catalysts, polymerization initiators, inorganic pigments, organic pigments, extender pigments, clay minerals, waxes, surfactants, stabilizers, flow regulators, coupling agents, dyes, leveling agents, rheology control agents, ultraviolet absorbers, antioxidants, flame retardants, plasticizers, reactive diluents, and the like can be mentioned.

[0053] In the resin composition for electronic materials, the ratio of the content of the titanium oxide particles of the embodiment to 100% by volume of the total volume of the resin composition for electronic materials is preferably 5 to 90% by volume.

[0054] The resin composition for electronic materials can be used, for example, for the manufacture of electronic devices or members for electronic devices constituting electronic devices, and in addition to a molding material, it can be used as, for example, a sealing agent, an adhesive, a coating agent, and the like.

[0055] As one embodiment of the present invention, a molded article of the resin composition for electronic materials of the above embodiment can be provided. The molded article may be a molded article containing the resin composition for electronic materials of the embodiment, or may be a molded article made of the resin composition for electronic materials of the embodiment.

[0056] Also, as one embodiment of the present invention, a member for electronic equipment containing the titanium oxide particles of the embodiment can be provided. Also, as one embodiment of the present invention, an electronic device containing the titanium oxide particles of the embodiment can be provided.

[0057] Examples of the electronic device or the member for electronic equipment constituting the electronic device include cables such as flexible flat cables, antennas, antenna modules, various electronic circuit boards (for example, printed boards such as flexible printed boards and build-up printed boards), prepregs, laminates, metal foil-clad laminates such as copper-clad laminates, resin sheets, insulating materials, resin films, adhesive films, fusion films, semiconductor packages, and the like. These electronic devices or members for electronic equipment constituting the electronic device can include the molded article of the above embodiment.

[0058] Examples of the above communication devices include mobile phones, smartphones, IoT devices, and the like. These communication devices or members for electronic equipment constituting the communication device can include the molded article of the above embodiment.

[0059] The titanium oxide particles of the embodiment can be produced, for example, by the <<Method for Producing Titanium Oxide Particles>> described later. Note that the titanium oxide particles of the present invention are not limited to those produced by the method for producing titanium oxide particles of the following embodiment.

[0060] <<Method for Producing Titanium Oxide Particles>> The method for producing titanium oxide particles according to the embodiment includes (I) firing a titanium compound in the presence of a molybdenum compound and a potassium compound and / or a sodium compound, or (II) firing a titanium compound in the presence of a molybdenum compound.

[0061] The method for producing titanium oxide particles according to the embodiment may include a mixing step of mixing a titanium compound, a molybdenum compound, and a potassium compound and / or a sodium compound to form a mixture, and a firing step of firing the mixture. The molar ratio of Mo / M1 (where M1 represents Na and K) in the mixture in the mixing step may be greater than 0.5, may be 0.65 or more, may be 0.9 or more, and may be 1 or more.

[0062] According to the method for producing titanium oxide particles in which the value of the molar ratio (Mo / M1) is greater than 0.5, the flux effect is improved, and it is possible to easily improve the average crystallite size of titanium dioxide contained in the produced titanium oxide particles.

[0063] The molar ratio of Mo / M1 (where M1 represents Na and K) in the mixture in the mixing step may be 3 or less, may be 2 or less, and may be 1.5 or less.

[0064] As an example of the numerical range of the molar ratio of Mo / M1 (where M1 represents Na and K) in the mixture in the mixing step, it may be greater than 0.5 and 3 or less, may be 0.65 or more and 3 or less, may be 0.9 or more and 2 or less, and may be 1 or more and 1.5 or less. When the mixture does not contain K, M1 may be only Na. When the mixture does not contain Na. M1 may be only K. When the mixture contains both Na and K, M1 may be the total amount of Na and K.

[0065] As the amounts of the titanium compound and the molybdenum compound used, in order to obtain the titanium oxide particles of the above-described embodiment with high efficiency, the molar ratio of titanium atoms in the mixture to molybdenum atoms in the molybdenum compound is preferably in the range of 0.5 to 50.0, more preferably in the range of 0.5 to 35.0, and particularly preferably in the range of 1.5 to 20.

[0066] In the case of the production method of the aforementioned (II), the molar ratio of titanium atoms in the mixture to molybdenum atoms in the molybdenum compound is preferably in the range of more than 35.0 and 120.0 or less, and more preferably in the range of more than 35.0 and 100.0 or less. Being within the above range is preferable from the viewpoints of the crucible releasability of the obtained titanium oxide particles and the ease of washing.

[0067] Here, instead of at least a part of the molybdenum compound and the potassium compound, a compound containing molybdenum and potassium such as potassium molybdate (for example, K2Mo n O 3n+1 , n = 1, 2, 3) can also be used. Similarly, instead of at least a part of the molybdenum compound and the sodium compound, a compound containing molybdenum and sodium such as sodium molybdate (for example, Na2Mo n O 3n+1 , x = 1, 2, 3) can also be used. In particular, the use of Na2Mo2O7 or K2Mo2O7 has a high flux effect on crystal growth, and the average crystallite size of titanium dioxide tends to be easily improved. The step of mixing a titanium compound and a compound containing molybdenum and potassium and / or sodium to form a mixture is also regarded as the step of mixing a titanium compound, a molybdenum compound, a potassium compound and / or a sodium compound to form a mixture.

[0068] [Mixing Step] The mixing step is a step of mixing a titanium compound, a molybdenum compound, a potassium compound and / or a sodium compound to form a mixture, or a step of mixing a titanium compound and a molybdenum compound to form a mixture.

[0069] The mixing state of the mixture is not particularly limited, and it is sufficient that the molybdenum compound and the potassium compound and / or sodium compound are present in the same space where they can act on the titanium compound, or that the molybdenum compound is present in the same space where it can act on the titanium compound. Specifically, even if they are not mixed, it may be any of simple mixing of powders, mechanical mixing using a pulverizer or the like, mixing using a mortar or the like, etc., and may be mixing in a dry state or a wet state.

[0070] Hereinafter, the above raw material compounds will be described.

[0071] (Titanium compound) The titanium compound used as a raw material (hereinafter sometimes referred to as a precursor) is not particularly limited as long as it becomes titanium oxide by heat treatment. For example, titanium chloride, titanium sulfate, metatitanic acid, amorphous titanium oxide, anatase-type titanium oxide, rutile-type titanium oxide, a mixed-type titanium oxide of anatase type and rutile type, etc. can be used. There are no particular limitations on the physical forms such as the shape, particle diameter, and specific surface area of the titanium compound as a precursor.

[0072] Since the shape of the titanium oxide particles after firing hardly reflects the shape of the titanium compound as a precursor, for example, spherical, amorphous, structured bodies with an aspect (wire, fiber, ribbon, tube, etc.), sheet, etc. can all be suitably used.

[0073] Similarly, regarding the particle diameter of the titanium oxide particles after firing, since the particle diameter of the titanium compound as a precursor is hardly reflected, titanium compounds ranging from several nm to several hundred μm can be suitably used. Furthermore, the specific surface area of the titanium compound as a precursor is not particularly limited, and any titanium compound can be suitably used.

[0074] The titanium compound as the precursor may consist of only the titanium compound or may contain a small amount of a metal compound in the titanium compound. For example, an aluminum compound, a silicon compound, a zinc compound, etc. may be present. When using a molybdenum compound as a fluxing agent to efficiently form titanium oxide crystals, the content of these metal compounds in the titanium compound of the precursor is preferably 20% by mass or less, and more preferably 10% by mass or less.

[0075] Also, the titanium compound as the precursor may be a composite of a titanium compound and an organic compound. For example, an organic / inorganic composite obtained by modifying titanium oxide using an organic silane, a titanium compound composite adsorbed with a polymer, etc. can also be preferably used. When using these composites, there is no particular limitation on the content rate of the organic compound, but in order to efficiently produce rutile-type titanium oxide particles having a substantially spherical automorphic shape, the content rate is preferably 60% by mass or less, and more preferably 30% by mass or less.

[0076] (Molybdenum compound) By sintering the titanium compound in the presence of molybdenum, titanium oxide particles containing molybdenum can be obtained. At this time, the molybdenum compound is used as a fluxing agent. The molybdenum compound may be molybdenum oxide or a compound containing an acid radical anion (MO x n- ; hereinafter, M represents a metal) formed by the bonding of molybdenum metal with oxygen.

[0077] The acid radical anion (MO x n- ) is formed by the bonding of molybdenum metal with oxygen, and the compound containing the acid radical anion is not particularly limited as long as it is a compound that converts to molybdenum oxide below the firing temperature. For example, molybdic acid, H3PMo 12 O 40 , H3SiMo 12 O 40 , NH4Mo7O 12etc. can be preferably used. Among these, considering the cost aspect, it is preferable to use molybdenum oxide. In this case, with the formation of titanium oxide particles, molybdenum oxide sublimes and most of it can be removed from the reaction system.

[0078] Also, as the compound containing the acid radical anion (MO x n- ) formed by the combination of molybdenum metal and oxygen, molybdenum metal salts that do not decompose at the firing temperature can also be used. For example, sodium molybdate, potassium molybdate, lithium molybdate, or a mixture of multiple molybdenum metal salts can be preferably used. For example, sodium molybdate, potassium molybdate, lithium molybdate, etc. that are soluble in water are preferable because they can be easily removed by water washing. As the fluxing agent, a mixture of a molybdenum compound and a metal compound can also be used. In this case, the molybdenum compound and the metal compound are reacted by high-temperature firing to form a molybdenum metal salt. The formed molybdenum metal salt is not particularly limited as long as it can form titanium oxide particles as the fluxing agent.

[0079] For example, a compound containing molybdenum and potassium, which is suitable as the fluxing agent, can be produced, for example, from a molybdenum compound and a potassium compound, which are cheaper and more easily available, during the firing process. Here, when using the molybdenum compound and the potassium compound as the fluxing agent, when using the compound containing molybdenum and potassium as the fluxing agent, both cases are combined and considered as the case of using the molybdenum compound and the potassium compound as the fluxing agent, that is, in the presence of the molybdenum compound and the potassium compound.

[0080] For example, a compound containing molybdenum and sodium, which is suitable as a fluxing agent, can be produced during the firing process using, for example, a more inexpensive and easily available molybdenum compound and sodium compound as raw materials. Here, when using a molybdenum compound and a sodium compound as a fluxing agent, and when using a compound containing molybdenum and sodium as a fluxing agent, both cases are considered as using a molybdenum compound and a sodium compound as a fluxing agent, that is, in the presence of a molybdenum compound and a sodium compound.

[0081] Also, potassium molybdate (K2Mo n O 3n+1 , n = 1 to 3) contains potassium and thus may also have the function as a potassium compound described later.

[0082] Also, sodium molybdate (Na2Mo n O 3n+1 , n = 1 to 3) contains sodium and thus may also have the function as a sodium compound described later.

[0083] The fluxing agent containing a molybdenum compound may consist only of a molybdenum compound or may contain other inorganic compounds. For example, it may contain a calcium compound, an iron compound, a silicon compound, etc. In order to efficiently form rutile-type titanium oxide particles using a molybdenum compound as a fluxing agent, the content of these inorganic compounds is preferably 20% by mass or less, more preferably 10% by mass or less, based on the oxide.

[0084] In addition, the flux agent containing the molybdenum compound may be a complex of the molybdenum compound and an organic compound. For example, an organic / inorganic complex obtained by modifying the molybdenum compound using an organic silane, a molybdenum compound complex adsorbed with a polymer, etc. can also be preferably used. When using these complexes, the content of the organic compound is not particularly limited, but in order to efficiently form rutile-type titanium oxide particles, the content is preferably 60% by mass or less, and more preferably 30% by mass or less.

[0085] The above-mentioned molybdenum compounds may be used alone or in combination of two or more.

[0086] (Potassium compound) The potassium compound is not particularly limited, and examples thereof include potassium chloride, potassium chlorite, potassium chlorate, potassium sulfate, potassium hydrogen sulfate, potassium sulfite, potassium hydrogen sulfite, potassium nitrate, potassium carbonate, potassium hydrogen carbonate, potassium acetate, potassium oxide, potassium bromide, potassium bromate, potassium hydroxide, potassium silicate, potassium phosphate, potassium hydrogen phosphate, potassium sulfide, potassium hydrogen sulfide, potassium molybdate, potassium tungstate, etc. At this time, similar to the case of the molybdenum compound, the potassium compound contains isomers. Among these, it is preferable to use potassium carbonate, potassium hydrogen carbonate, potassium oxide, potassium hydroxide, potassium chloride, potassium sulfate, potassium molybdate, and more preferably potassium carbonate, potassium hydrogen carbonate, potassium chloride, potassium sulfate, potassium molybdate.

[0087] In addition, the above-mentioned potassium compounds may be used alone or in combination of two or more.

[0088] Also, similar to the above, since potassium molybdate contains molybdenum, it may also have the function as the above-mentioned molybdenum compound.

[0089] (Sodium compound) The sodium compound is not particularly limited, and examples thereof include sodium carbonate, sodium molybdate, sodium oxide, sodium sulfate, sodium hydroxide, sodium nitrate, sodium chloride, metallic sodium, and the like. Among these, from the viewpoints of industrial availability and ease of handling, it is preferable to use sodium carbonate, sodium molybdate, sodium oxide, or sodium sulfate.

[0090] Note that the above-mentioned sodium compounds may be used alone or in combination of two or more.

[0091] Also, in the same manner as above, since sodium molybdate contains molybdenum, it may also have the function as the above-mentioned molybdenum compound.

[0092] Thus, although there may be overlapping notations as molybdenum compounds in classification, the molybdenum compound is at least one compound selected from the group consisting of molybdenum oxide, potassium molybdate, and sodium molybdate, it is preferable that the sodium compound is sodium carbonate or sodium molybdate, and the potassium compound is potassium carbonate or potassium molybdate.

[0093] The mixing step is a step of mixing a titanium compound with a compound containing molybdenum and potassium or a compound containing molybdenum and sodium to form a mixture, and it is more preferable that the compound containing molybdenum and potassium is K2Mo2O7, and the compound containing molybdenum and sodium is Na2Mo2O7.

[0094] [Firing step] The firing step is a step of firing the mixture. Regarding this firing, when the firing temperature exceeds 700 °C, the molybdenum compound functions as a fluxing agent and effectively contributes to the formation of titanium oxide particles with a rutile crystallization rate of 90% or more.

[0095] Furthermore, the firing temperature may be any temperature equal to or higher than the temperature at which the target titanium oxide particles are formed. Specifically, the maximum temperature may be in the range of 700 to 1400°C. In particular, to efficiently form titanium oxide particles with an average crystallite size of 220 nm or more determined from the peak at 2θ = 27.5° ± 1.0° obtained by X-ray diffraction measurement of titanium dioxide, firing at a temperature in the range of 800 to 1400°C is more preferable, firing at a temperature in the range of 800 to 1350°C is even more preferable, and firing at a temperature in the range of 1200 to 1350°C is most preferable. In the case of Production Method (II), the firing temperature is more preferably firing in the range of 800 to 1400°C, even more preferably firing in the temperature range of 800 to 1350°C, and most preferably firing in the temperature range of 900 to 1100°C.

[0096] Regarding the firing time, it is preferable to raise the temperature to the predetermined firing temperature in the range of 20 minutes to 10 hours and hold the temperature at the firing temperature in the range of 5 minutes to 45 hours. In the case of Production Method (II), it is preferable to raise the temperature to the predetermined firing temperature in the range of 20 minutes to 10 hours and hold the temperature at the firing temperature in the range of 5 minutes to 45 hours, more preferably in the range of 15 minutes to 30 hours, and most preferably in the range of 2 to 7 hours.

[0097] Preferably, by selecting the conditions of a firing temperature of 700 to 1400°C and a firing temperature holding time of 5 minutes to 45 hours, more preferably a firing temperature of 800 to 1400°C and a firing temperature holding time of 5 minutes to 45 hours, even more preferably a firing temperature of 800 to 1350°C and a firing temperature holding time of 10 minutes to 30 hours, and particularly preferably a firing temperature of 1200 to 1350°C and a firing temperature holding time of 15 to 30 hours, the titanium oxide particles of the above embodiments can be easily obtained.

[0098] The firing atmosphere is not particularly limited. For example, firing can be performed in an atmosphere of air or oxygen or an inert atmosphere such as nitrogen or argon. However, considering cost, an air atmosphere is more preferable.

[0099] The apparatus for firing is not particularly limited, and a so-called firing furnace can be used. The firing furnace is preferably made of a material that does not react with sublimated molybdenum oxide, and it is more preferable to use a highly airtight firing furnace so as to efficiently utilize molybdenum oxide.

[0100] According to the method for producing titanium oxide particles of the embodiment, the titanium oxide particles of the above embodiment can be produced.

Examples

[0101] Next, examples are shown to explain the present invention in more detail, but the present invention is not limited to the following examples.

[0102] <Analysis and Evaluation> Using the powders of each example and comparative example as samples, the following measurements were performed.

[0103] [Average particle size] The sample was photographed with a scanning electron microscope (SEM), and for the particles confirmed on the two-dimensional image, among the distances between two points on the contour line of the primary particles of 50 or more randomly selected particles, the maximum length was taken as the particle size, and the average value thereof was taken as the average particle size.

[0104] [Analysis of crystal phase by X-ray diffraction (XRD) method] The prepared sample was placed on a holder for measurement sample with a depth of 0.5 mm, filled with a constant load to make it flat, and then set in a wide-angle X-ray diffraction (XRD) apparatus (Ultima IV, manufactured by Rigaku Corporation), and measured under the conditions of Cu / Kα ray, 40 kV / 30 mA, scan speed 2 degrees / minute, and scan range 10 to 70 degrees.

[0105] [Median diameter D 50 Measurement] Using a laser diffraction dry particle size distribution analyzer (HELOS (H3355) & RODOS, manufactured by Nippon Laser Co., Ltd.), the particle size distribution of the sample powder was measured dry under the conditions of a dispersion pressure of 3 bar and a suction pressure of 90 mbar. The particle size at the point where the volume integration % distribution curve intersects the horizontal axis of 50% was determined as D 50 as follows.

[0106] [Composition Analysis by X-ray Fluorescence (XRF)] Using an X-ray fluorescence (XRF) analyzer (PrimusIV, manufactured by Rigaku Corporation), approximately 70 mg of the prepared sample was placed on a filter paper, covered with a PP film, and the composition analysis was performed. The amounts of various elements determined by the XRF analysis results were converted to oxides (mass %) for the oxides described in Table 2, and the ratios of the contents of various oxides to 100 mass % of the total mass of the sample were calculated.

[0107] [Measurement of Crystallite Size] Using an X-ray diffractometer (SmartLab, manufactured by Rigaku Corporation), CALSA was used as a detector, and PDXL2 was used as analysis software for the measurement. The measurement method was the 2θ / θ method. Under the following measurement conditions, the average crystallite size of titanium dioxide was calculated using the Scherrer equation from the half-width of the peak that appears at 2θ = 27.5° ± 1.0°. (Measurement Conditions) Scan range: 2θ = 10 to 70° Step: 2θ = 0.002° Speed: 2θ = 0.05° / min βs = 20 rpm Soller / PSC: 2θ = 2.5° short Soller: 2θ = 2.5° Analysis software: PDXL2 Instrument inherent width: None Peak shape: Automatically analyzed using the CALSA function

[0108] [Measurement of Relative Permittivity and Dielectric Loss Tangent] The sample powder filled in the measurement tube was set in a cavity resonator (CP-001-PW, manufactured by EM Lab), and the complex relative permittivity of the mixture of the sample powder and air at 1 GHz was measured at a measurement temperature of 25 °C using a vector network analyzer (P9373A, manufactured by Keysight). Using Lichtenecker's rule, the relative permittivity (ε r ), and the loss tangent (tanδ) of the sample powder were calculated from the measured complex relative permittivity, the volume fraction of the sample powder, and the complex relative permittivity of air. The specific calculation was performed as follows. According to Lichtenecker's rule, the complex relative permittivity of the mixture of the sample powder and air is given by the following equation (1).

[0109] logε = V1logε1 + V2logε2 ··· (1)

[0110] ε: Complex relative permittivity of the mixture of the sample powder and air, ε1: Complex relative permittivity of the sample powder, ε2: Complex relative permittivity of air, V1: Volume fraction of the sample powder, V2: Volume fraction of air

[0111] Since the complex relative permittivity of air is 1, the above equation (1) can be rewritten as follows logε = V1logε1 ··· (2)

[0112] The measured values and the volume fraction of the sample powder were substituted into the above equation (2) to calculate the complex relative permittivity of the sample powder. Since the following relationships hold between the real part (ε') and the imaginary part (ε'') of the complex relative permittivity, the relative permittivity (εr) and the loss tangent (tanδ) of the sample powder were calculated from the calculated complex relative permittivity.

[0113] εr = ε' tanδ = ε'' / ε'

[0114] [Evaluation of crucible release property] The fired product was taken out of the crucible, and the detachability from the crucible was evaluated from the ratio of the amount of powder remaining on the wall and bottom surfaces of the crucible. The detachability from the crucible was calculated using the weight of the crucible (A), the weight of the crucible and powder after firing (B), and the weight of the crucible and powder after removal (C). If the detachability from the crucible was less than 0.1, it was evaluated as "〇", and if it was 0.1 or more, it was evaluated as "×". Detachability from crucible = (C - A) / (B - A)

[0115] <Production of Potassium Molybdate> [Production Example 1] 36.17 g of potassium carbonate (K2CO3) and 75.34 g of molybdenum trioxide (MoO3) were mixed to obtain a mixture. The obtained mixture was charged into a crucible and fired in a muffle furnace at 700 °C for 5 hours. The temperature was raised at a rate of 5 °C / min. After cooling to room temperature, the crucible was taken out to obtain the powder of Production Example 1. When XRD measurement was performed on this powder, scattering peaks derived from K2Mo2O7 were confirmed, and the synthesis of K2Mo2O7 was confirmed.

[0116] <Production of Titanium Oxide Particles> [Example 1] 20 g of titanium oxide (TiO2) and 20 g of potassium molybdate (K2Mo2O7) produced in Production Example 1 above were charged into a 100 mL polypropylene bottle and mixed and pulverized for 30 minutes using a paint shaker to obtain a mixture. After the obtained mixture was further uniformly mixed in a mortar, it was charged into a crucible and fired in a muffle furnace at 800 °C for 24 hours. The temperature was raised at a rate of 5 °C / min. After cooling to room temperature, the crucible was taken out to obtain a powder. Subsequently, the powder was dispersed in 80 ml of pure water for 30 minutes and then centrifuged at 5000 rpm for 10 minutes to remove the supernatant. This operation was repeated 4 times. The obtained precipitate was dried at 80 °C for 24 hours and pulverized in a mortar to obtain the pale yellow powder of Example 1.

[0117] [Example 2] In Example 1, instead of titanium oxide, 24.51 g of metatitanic acid (manufactured by Xuan Cheng Jing Rui New Materials Co., Ltd., VK-P101, H2TiO3) was used, and the yellow powder of Example 2 was obtained by the same operation as in Example 1 except that the firing temperature was changed as described in Table 1.

[0118] [Example 3] In Example 1, the yellow powder of Example 3 was obtained by the same operation as in Example 1 except that the firing temperature was changed as described in Table 1.

[0119] [Example 4] In Example 1, instead of titanium oxide, 110.26 g of metatitanic acid (manufactured by Xuan Cheng Jing Rui New Materials Co., Ltd., VK-P101, H2TiO3) was used, and instead of potassium molybdate (K2Mo2O7), 24.7 g of sodium carbonate (Na2Co3) and 67.2 g of molybdenum oxide (MoO3) were used. The yellow powder of Example 4 was obtained by the same operation as in Example 1 except that the firing temperature was changed as described in Table 1.

[0120] [Example 5] In Example 4, the yellow powder of Example 5 was obtained by the same operation as in Example 4 except that 32.2 g of potassium carbonate (K2Co3) was used instead of sodium carbonate.

[0121] [Reference Example 1] 20 g of titanium oxide (TiO2) and 1 g of molybdenum oxide were charged into a 100 mL polypropylene bottle and mixed and pulverized for 30 minutes using a paint shaker to obtain a mixture. After further uniformly mixing the obtained mixture in a mortar, it was charged into a crucible and fired in a muffle furnace at 1000 °C for 5 hours. The temperature was raised at 5 °C / min. After cooling to room temperature, the crucible was taken out to obtain a powder. Subsequently, the powder was dispersed in 80 ml of pure water for 30 minutes and then centrifuged at 5000 rpm for 10 minutes to remove the supernatant. This operation was repeated 4 times. The obtained precipitate was dried at 80 °C for 24 hours and pulverized in a mortar to obtain the pale yellow powder of Reference Example 1.

[0122] [Reference Example 2] In Reference Example 1, except that 0.4 g of molybdenum oxide was used and the firing temperature was changed as described in Table 1, the pale yellow powder of Reference Example 2 was obtained by the same operation as in Reference Example 1.

[0123] [Reference Example 3] In Reference Example 1, except that 0.6 g of molybdenum oxide was used and the firing temperature was changed as described in Table 1, the pale yellow powder of Reference Example 3 was obtained by the same operation as in Reference Example 1.

[0124] [Comparative Example 1] Commercially available titanium oxide particles (manufactured by Teika Co., Ltd.) were used as the powder of Comparative Example 1.

[0125] The above synthesis conditions are shown in Table 1. "-" indicates that the corresponding compound was not used.

[0126]

Table 1

[0127] [Results] SEM images of the powders obtained in Examples 1 to 5 and Reference Examples 1 to 3 above are shown in Figures 1 to 8.

[0128] The results of the above evaluations are shown in Table 2. "N.D." is an abbreviation for not detected, indicating non-detection.

[0129]

Table 2

[0130] Table 2 describes the particle shapes of each example and comparative example as determined from the SEM images. When particles of different shapes are observed to be mixed, the representative shape (the most frequently observed shape) is described.

[0131] The results of the XRD analysis of the sample of Example 1 are shown in Fig. 9. Sharp scattering peaks derived from rutile-type titanium dioxide appeared, and no crystal system peaks other than the rutile crystal structure were observed.

[0132] From the above SEM observation and XRD analysis results, it was confirmed that the powders obtained in each example were titanium oxide particles containing molybdenum and rutile-type titanium dioxide.

[0133] The titanium oxide particles of Examples 1 to 5 had a large average crystallite size of 220 nm or more of titanium dioxide, and had a lower value of dielectric tangent at 1 GHz and could reduce dielectric loss due to heat generation compared to the titanium oxide particles of Comparative Example 1.

[0134] Each configuration and their combinations, etc. in each embodiment are examples, and additions, omissions, substitutions, and other changes of the configuration are possible without departing from the spirit of the present invention. Further, the present invention is not limited by each embodiment and is limited only by the scope of the claims.

Claims

1. Contains titanium dioxide, The titanium dioxide particles have an average crystallite size of 220 nm or more, determined from a peak at 2θ=27.5°±1.0° obtained by X-ray diffraction measurement.

2. 2. The titanium oxide particles according to claim 1, wherein the average particle size of the titanium oxide particles is 0.1 to 300 μm.

3. 3. The titanium oxide particles according to claim 1 or 2, which contain molybdenum.

4. The titanium dioxide particles according to claim 1 or 2, wherein the titanium dioxide comprises rutile titanium dioxide.

5. 3. The titanium oxide particles according to claim 1, having a dielectric loss tangent at 1 GHz of 0.0040 or less.

6. 3. The titanium oxide particles according to claim 1 or 2, which are used as electronic materials.

7. A resin composition for electronic materials, comprising a resin and the titanium oxide particles according to claim 1 or 2.

8. A molded article made of the resin composition for electronic materials according to claim 7.

9. A member for electronic devices, comprising the titanium oxide particles according to claim 1 or 2.

10. A method for producing titanium oxide particles according to claim 1 or 2, comprising the steps of: a mixing step of mixing a titanium compound, a molybdenum compound, and a potassium compound and / or a sodium compound to obtain a mixture; A calcination step of calcining the mixture, Mo / M1 in the mixture (wherein M1 represents Na and K). ) is greater than 0.

5.

11. the mixing step is a step of mixing a titanium compound with a compound containing molybdenum and potassium or a compound containing molybdenum and sodium to obtain a mixture, The compound containing molybdenum and potassium is K ２ M.O. ２ O ７ and The compound containing molybdenum and sodium is Na ２ M.O. ２ O ７ The method for producing titanium oxide particles according to claim 10,

12. The method for producing titanium oxide particles according to claim 10, wherein the calcination step comprises calcining the mixture at a calcination temperature of 1200 to 1350° C. for a retention time at the calcination temperature of 15 to 30 hours.

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