Spherical composite oxide particle material, production method therefor, slurry composition, and transparent resin composition

Abstract

The present invention addresses the problem of providing: a spherical composite oxide particle material having high transparency and composed of a composite oxide containing Si and Al; a production method therefor; a slurry composition; and a transparent resin composition. This spherical composite oxide particle material is composed of a composite oxide containing Si and Al and has an alkali metal content of at most 5 ppm and a degree of crystallinity of at most 0.5%. The transparency of said material when dispersed in a resin material can be improved by setting the degree of crystallinity to at most 0.5%. It is particularly preferable that the mass of Al is less than 50% with respect to the mass of Si and Al, the number of moles of Al is at least 10% with respect to the number of moles of Si, the refractive index is 1.50±0.03, the circularity is at least 0.9, and the volume-average particle diameter is 0.1-20 μm.

Description

Spherical composite oxide particle material, its manufacturing method, slurry composition, and transparent resin composition

[0001] The present invention relates to a spherical composite oxide particle material, a method for producing the same, a slurry composition, and a transparent resin composition.

[0002] Resin compositions containing dispersed fillers made of metal oxide particles are used to achieve heat resistance and low thermal expansion of resins. When a resin composition requires optical properties (transparency) in addition to heat resistance and low thermal expansion, the refractive index of the dispersed filler needs to be close to that of the resin material.

[0003] Silica and alumina are commonly used as metal oxides for fillers. Silica has a refractive index of 1.46, and alumina has a refractive index of 1.77. When using a resin material with a refractive index significantly different from these refractive indices, it is difficult to obtain a resin composition with high transparency even if silica or alumina is used. Therefore, in conventional technology, a composite oxide of silica and alumina is formed to control the refractive index between 1.46 and 1.77, and the composite oxide is used as a filler (Patent Documents 1 and 2).

[0004] Patent Document 1 describes the method as "producing the emulsion by a method including a step of mixing raw materials containing an aqueous alkali silicate solution, an aluminum compound or an aqueous solution thereof, a surfactant, and an organic solvent in a predetermined ratio to obtain an emulsion, and a step of mixing the emulsion obtained in the mixing step with at least one salt selected from inorganic salts and organic salts" (Claim 9, paragraph 0007, etc.).

[0005] In Patent Document 2, a mullite composition (Al ６ O １３ Si ２ The present invention discloses a method for producing a composite oxide powder containing mullite by reacting metallic silicon and metallic aluminum mixed in a molar ratio of 1:1 with oxygen in a flame.

[0006] JP 2020-033240 A JP 07-108766 A

[0007] In the invention of Patent Document 1, particulate silica is produced using an aqueous alkali silicate solution containing an alkali metal as a raw material (see paragraph 0029), and therefore the obtained particulate silica contains a large amount of alkali metal.

[0008] Furthermore, Patent Document 2 aims to produce mullite, and a mixture of mullite, which is a crystalline composite oxide, and an amorphous composite oxide is obtained, so it is difficult to say that the resulting mixture has sufficient transparency when used as a filler in a transparent resin composition.

[0009] The present invention was completed in view of the above-mentioned circumstances, and an object of the present invention is to provide a highly transparent spherical composite oxide particle material composed of a composite oxide containing Si and Al, a method for producing the same, a slurry composition, and a transparent resin composition.

[0010] (1) The spherical composite oxide particle material of the present invention, which solves the above-mentioned problems, is composed of a composite oxide containing Si and Al, has an alkali metal content of 20 ppm or less, and has a crystallinity of 0.5% or less.

[0011] By limiting the content of alkali metals such as Na, which tend to leach out to the outside, to 20 ppm or less, the adverse effects of alkali metals can be suppressed.Furthermore, by limiting the crystallinity to 0.5% or less, the transparency when dispersed in a resin material can be improved.

[0012] In particular, it is preferable that the mass of Al is less than 50% based on the mass of Si and Al, the number of moles of Al is 10% or more based on the number of moles of Si, the refractive index is 1.50±0.03, the circularity is 0.9 or more, and the volume average particle size is 0.1 μm or more and 20 μm or less. (2) Another spherical composite oxide particulate material of the present invention that solves the above problems is a spherical composite oxide particulate material that can be produced by a method for producing a spherical composite oxide particulate material, the method comprising: a preparation step of preparing a raw particle material containing metallic silicon and metallic aluminum and having an alkali metal content of 20 ppm or less; and a deflagration and spheroidization step of introducing the raw particle material into a high-temperature oxidizing atmosphere, deflagrating it to form an oxide, and then rapidly cooling it to spheroidize it, thereby producing a spherical composite oxide particulate material having a crystallinity of 0.5% or less. (3) A method for producing a spherical complex oxide particulate material of the present invention that solves the above-mentioned problems comprises: a preparation step of preparing a raw particle material containing metallic silicon and metallic aluminum and having an alkali metal content of 20 ppm or less; and a deflagration and spheroidization step of introducing the raw particle material into a high-temperature oxidizing atmosphere, deflagrating it to form an oxide, and then rapidly cooling it to spheroidize it to form a spherical complex oxide particulate material having a crystallinity of 0.5% or less. (4) A slurry composition of the present invention that solves the above-mentioned problems comprises the spherical complex oxide particulate material of the present invention and a dispersion medium for dispersing the spherical complex oxide particulate material. (5) A transparent resin composition of the present invention that solves the above-mentioned problems comprises the spherical complex oxide particulate material of the present invention and a transparent resin material for dispersing the spherical complex oxide particulate material.

[0013] The spherical composite oxide particle material of the present invention has the above-mentioned structure, and thus can improve transparency when dispersed in a resin material or a dispersion medium.

[0014] 1 shows XRD spectra of each test sample in the examples.

[0015] The spherical composite oxide particle material of the present invention will be described in detail below based on the following embodiments. The spherical composite oxide particle material of this embodiment can be used as a composition dispersed in a resin material or a dispersion medium. In particular, by dispersing the spherical composite oxide particle material in a transparent resin material to form a transparent resin composition, the material can be used in electronic materials such as photonic-electronic integrated devices that process optical and electrical signals in logic ICs and analog ICs, optical materials such as lenses, LED encapsulants, dental materials, and more. (Spherical Composite Oxide Particle Material) The spherical composite oxide particle material of this embodiment is composed of an oxide (including a composite oxide) containing Si and Al and has a crystallinity of 0.5% or less. The Si / Al composition ratio is preferably less than 50% by mass of Al based on the mass of Si and Al, and more preferably 35%, 30%, 27.5%, 25%, or 20%.

[0016] Furthermore, the mole number of Al is preferably 10% or more, more preferably 15% or more, and even more preferably 20% or more, based on the mole number of Si. These upper and lower limit values ​​can be combined arbitrarily. The spherical composite oxide particle material preferably has a uniform composition.

[0017] The spherical composite oxide particle material may contain oxides of other metals in addition to oxides of Si and Al. The content of Si and Al is determined based on the total mass of the material. ２ , Al ２ O ３ Preferably, the lower limit of the mass of Si and Al oxides calculated as SiO 2 is 85%, 90%, 95%, or 100%.

[0018] The alkali metal content of the spherical composite oxide particle material is 5 ppm or less, preferably 3 ppm or less, and more preferably 1 ppm or less. The alkali metal content is measured by ICP atomic emission spectrometry or the like.

[0019] The degree of crystallinity of the spherical composite oxide particle material is preferably 0.5% or less, and more preferably 0.3% or less. The degree of crystallinity is measured by measuring the area (a) of the amorphous region and the area (b) of the crystalline region (40.8°) using a spectrum measured by XRD (CuKα radiation) from 5° to 90°, and calculating b / (a+b)×100(%).

[0020] The spherical composite oxide particle material preferably has a circularity of 0.9 or more, more preferably 0.95 or more, even more preferably 0.98 or more, and particularly preferably 0.99 or more. A larger circularity tends to improve the packing property when dispersed in a composition, and also tends to reduce the viscosity of the composition. The circularity can be determined by taking a photograph with an SEM and using the area and perimeter of the observed particle, as follows: (Circularity) = {4π × (Area) ÷ (Perimeter)} ２}. The closer to 1, the closer to a perfect sphere. Specifically, the average value measured for 100 particles using image analysis software (Asahi Kasei Engineering Co., Ltd.: Azo-kun) is adopted. The refractive index of the spherical composite oxide particle material is preferably 1.50±0.03. The refractive index can be controlled by controlling the ratio of Si to Al, and the refractive index can be increased by increasing the Al. It is preferable that all of the particles constituting the spherical composite oxide particle material fall within this range, and the range is preferably ±0.02, more preferably ±0.01, and particularly preferably ±0.005.

[0021] The refractive index of the spherical composite oxide particle material is measured by the following method. A plurality of mixed solvents with different blending ratios of two solvents with known refractive indices are prepared, and the particle material is dispersed in these at a concentration of 10 g / L. The refractive index of the mixed solution at the point where the mixed solution is most transparent is taken as the refractive index of the particle material. The refractive indices of the mixed solvents prepared are set in increments of 0.01, with 1.50 as the base.

[0022] The spherical composite oxide particle material preferably has a volume average particle size of 0.1 μm or more and 20 μm or less. The upper limit of the volume average particle size can be 20 μm, 10 μm, or 5 μm, and the lower limit can be 0.1 μm, 0.5 μm, or 1.0 μm. These upper and lower limit values ​​can be combined arbitrarily. The spherical composite oxide particle material is preferably dispersed into primary particles.

[0023] The spherical composite oxide particle material may be surface-treated. Examples of surface treatment agents include organosilicon compounds. Organoaluminum compounds and organotitanium compounds can also be used. Examples of organosilicon compounds include silane compounds such as silane coupling agents, and silazanes. Examples of silane compounds include compounds having an alkoxy group, a phenyl group, a vinyl group, an epoxy group, a methacryl group, an amino group, a ureido group, a mercapto group, an isocyanate group, or an acrylic group.

[0024] The amount of surface treatment agent bonded to the surface is not particularly limited, and can be selected as 100%, 75%, 50%, 25%, or the like, based on the amount of OH groups present on the surface of the spherical composite oxide particle material. Excessive amounts exceeding 100% (e.g., 120%, 150%) can also be selected. (Method for Producing Spherical Composite Oxide Particulate Material) The method for producing spherical composite oxide particulate material of this embodiment is a method for producing spherical composite oxide particulate material of this embodiment, and includes a preparation step, a deflagration and spheroidization step, and other steps that can be selected as necessary. Preparation Step: This step is a step for preparing a raw particle material. The raw particle material is a particle material containing metallic silicon and metallic aluminum, and can be a mixture of separate particle materials for metallic silicon and metallic aluminum, or a particle material composed of an alloy of metallic silicon and metallic aluminum. Since the purity of the raw particle material directly affects the purity of the spherical composite oxide particulate material produced, the purity of the raw particle material is adjusted to the required purity.

[0025] Metallic silicon or metallic aluminum can be melted and formed into a particulate material using an atomizer or by pulverization. The ratio of metallic silicon and metallic aluminum contained in the raw particulate material can be approximately the same as the ratio of Si and Al contained in the spherical composite oxide particulate material to be produced. The particle size of the raw particulate material is not particularly limited, but can be approximately 0.1 μm to 40 μm.

[0026] Furthermore, the raw particle material can be surface-treated. Surface treatment can prevent the raw particle material from agglomerating when placed in a high-temperature oxidizing atmosphere, as described below. Examples of surface treatments include organic silicon compounds such as silane compounds, organic aluminum compounds such as aluminate coupling agents, and organic titanium compounds such as titanate coupling agents. Deflagration and spheroidization process: This process involves placing the raw particle material in a high-temperature oxidizing atmosphere, and is also known as the VMC method. As a result, the raw particle material becomes an oxide through a deflagration reaction. The resulting oxide falls due to gravity, etc., and is rapidly cooled after being removed from the high-temperature oxidizing atmosphere, yielding a spherical composite oxide particle material. The resulting spherical composite oxide particle material can be recovered using a bag filter or cyclone.

[0027] The high-temperature oxidizing atmosphere can be, for example, a flame formed by burning a combustible gas in an oxidizing atmosphere. The high-temperature oxidizing atmosphere can be formed in an appropriate furnace. Examples of the combustible gas include hydrocarbon gases such as methane, propane, and butane, hydrogen, and ammonia. The oxidizing atmosphere (combustion-supporting gas) can be oxygen gas or air. The amount of oxygen in the oxidizing atmosphere can be 1.0 times or more, 1.1 times or more, 1.2 times or more, 1.3 times or more, 1.4 times or more, 1.5 times or more, 1.75 times or more, or 2.0 times or more of the amount of oxygen stoichiometrically required to oxidize the raw particle material and the combustible gas.

[0028] The raw material particles are preferably dispersed in a carrier gas and then charged. Examples of the carrier gas include air and nitrogen gas. The concentration of the raw material particles dispersed in the carrier gas is 0.3 kg / Nm. ３ ~8 kg / Nm ３The degree of surface treatment can be adjusted to about 100%. Other Steps After the deflagration and spheroidization step, other steps may be selected as needed, such as a surface treatment step and a classification step. If these steps are not particularly required, it does not matter whether they are performed before or after the deflagration and spheroidization step. Surface Treatment Step The surface treatment step is a step in which the spherical composite oxide particle material is surface-treated with a surface treatment agent such as an organosilicon compound, organoaluminum compound, or organotitanium compound. The surface treatment is carried out by contacting the surface with the surface treatment agent directly (either in liquid or gaseous form) or by contacting the surface with the surface treatment agent dissolved in some kind of solvent. After the surface treatment, heating can also be carried out to promote the reaction between the surface treatment agent and the surface of the spherical composite oxide particle material.

[0029] The surface treatment agent is not particularly limited, and examples thereof include those having a phenyl group, an alkyl group, a vinyl group, a methacryl group, an epoxy group, a phenylamino group, an amino group, a styryl group, and the like.

[0030] The amount of the surface treatment agent used for the surface treatment is not particularly limited, and can be selected from amounts such as 100%, 75%, 50%, and 25% based on the amount of OH groups present on the surface of the spherical composite oxide particle material. Excessive amounts exceeding 100% (e.g., 120%, 150%) can also be selected. Classification Process: The classification process is a process for adjusting the particle size distribution of the produced spherical composite oxide particle material and removing coarse particles. Examples of classification procedures include sieving using a sieve with appropriate mesh size, centrifugation in an appropriate dispersion medium, and sedimentation classification. Examples of appropriate dispersion mediums include gases such as air, and liquids such as organic solvents and water, which are exemplified in the slurry composition described below. Using a liquid as the dispersion medium allows impurities contained in the spherical composite oxide particle material to be transferred into the dispersion medium and then removed, thereby reducing the amount of impurities. The classification process can be repeated until the desired particle size distribution is achieved. Furthermore, the particle size distribution can be adjusted by mixing spherical composite oxide particle materials adjusted to different particle size distributions by classification procedures. (Slurry Composition) The slurry composition of this embodiment is a composition in which the spherical composite oxide particle material of this embodiment is dispersed in a dispersion medium such as an organic solvent. The organic solvent is not particularly limited, but examples include methanol, ethanol, isopropanol, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl acetate, ethyl acetate, toluene, hexane, THF, ethyl methyl ketone, methyl isobutyl ketone, cyclohexanone, dimethylacetamide, dimethylformamide, acetic acid, and oleic acid.

[0031] The mixing ratio of the spherical composite oxide particle material to the organic solvent is not particularly limited as long as fluidity is maintained. For example, the mass ratio of (particle material):(organic solvent) can be approximately 5:95 to 85:15. The slurry composition of this embodiment can be used to supply the particle material when mixed with a resin material or other particle material, or can be used to apply the particle material by applying it to a target site and then drying the organic solvent. (Transparent Resin Composition) The transparent resin composition of this embodiment is a composition in which the spherical composite oxide particle material of this embodiment is dispersed in a transparent resin material. Examples of transparent resin materials that can be used include polymeric compounds that can be melted by heating, polymeric compounds after curing, and polymer precursors that can be cured by reaction. Examples of transparent resin materials that can be used include, but are not limited to, acrylic resins, silicone resins, epoxy resins, urea resins, urea resins, polyester resins, polyimide resins, LCP resins (liquid crystal resins), COC resins (cyclic olefin copolymers), and fluororesins.

[0032] The mixing ratio of the spherical composite oxide particle material to the resin material is not particularly limited as long as fluidity is maintained, but for example, the mass ratio of (particle material):(resin material) can be about 5:95 (lower limit) to 90:10 (upper limit), with the lower limit being 10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, or 80:20. The resin composition of this embodiment can be used for some or all of the semiconductor encapsulation material, as well as for some or all of the substrate material.

[0033] The spherical composite oxide particle material and its manufacturing method of the present invention will be described in detail below with reference to the following examples. Example 1 A raw particle material was prepared by blending metallic silicon powder having an average particle size of 20 μm and a purity of 99% or more with metallic aluminum powder having an average particle size of 20 μm and a purity of 99% or more in a mass ratio of Si:Al=60:40 (preparation step).

[0034] The raw material particles were charged into a flame as a high-temperature oxidizing atmosphere formed in a furnace (volume 0.4 to 5 kL) from propane gas as a combustible gas and air as a combustion-supporting gas. The raw material particles were charged into air as a carrier gas at a density of 1500 g / Nm ３At a concentration of 0.4 Nm ３ The resulting spherical composite oxide particle material was collected by a bag filter and used as a test sample for this example. ２ The theoretical amount of oxygen required for combustion and oxidation ２The ratio of the amounts was 1.0 to 2.0 times. Example 2: A spherical composite oxide particulate material was produced in the same manner as in Example 1, except that the Si:Al ratio of the raw particle material was changed to 70:30, and used as the test sample of this example. Example 3: A spherical composite oxide particulate material was produced in the same manner as in Example 1, except that the Si:Al ratio of the raw particle material was changed to 74:26, and used as the test sample of this example. Example 4: A spherical composite oxide particulate material was produced in the same manner as in Example 1, except that the Si:Al ratio of the raw particle material was changed to 76:24, and used as the test sample of this example. Example 5: A spherical composite oxide particulate material was produced in the same manner as in Example 1, except that the Si:Al ratio of the raw particle material was changed to 80:20, and used as the test sample of this example. Comparative Example 1: A spherical composite oxide particulate material was produced in the same manner as in Example 1, except that the Si:Al ratio of the raw particle material was changed to 40:60, and used as the test sample of this comparative example. Comparative Example 2: A spherical composite oxide particle material was produced in the same manner as in Example 1, except that the Si:Al ratio of the raw particle materials was changed to 25:75. This was used as the test sample for this Comparative Example. Comparative Example 3: A spherical composite oxide particle material was produced in the same manner as in Example 1, except that the Si:Al ratio of the raw particle materials was changed to 15:85. This was used as the test sample for this Comparative Example. Comparative Example 4: Particulate silica was produced using the method described in Example 1 of Patent Document 1, and this was used as the test sample for this Comparative Example. Comparative Example 5: The test sample from Comparative Example 4 was dispersed in ion-exchanged water at a concentration of 20% by mass to prepare a dispersion, and then the dispersion medium was removed using a centrifuge to obtain particulate silica from which water-soluble impurities had been removed. This was then dried to obtain the test sample for this Comparative Example. Evaluation Method: Refractive Index: Multiple levels of mixed solvents containing two solvents with known refractive indices and different blend ratios were prepared. Particles were dispersed in these solvents. The refractive index of the mixed solution at the point where the mixed solution exhibited the highest transparency was used as the refractive index of the particles. Crystallinity: XRD measurements were performed using a Rigaku SmartLab X-ray diffractometer, and the ratio of amorphous to crystalline phases was calculated. For reference, the XRD spectra of Examples 1-5 and Comparative Examples 1-5 are shown in Figure 1. As is clear from Figure 1, in Comparative Examples 1-3, a peak corresponding to crystals is present at 40.8°, indicating a higher degree of crystallinity than in the Examples.In Figure 1, the horizontal axis represents 2θ (°), and the vertical axis represents intensity (arbitrary units). Al (mol%) and Si (mol%) were calculated using an X-ray fluorescence analyzer (Supermini 200, manufactured by Rigaku Corporation) after 6.0 to 6.1 g of the test sample from each Example and Comparative Example was placed in a cell. From the measurement results, the percentage of Al moles relative to the number of Si moles was calculated using Al (mol%) / Si (mol%) x 100 (%). Equivalent circle diameter (particle diameter) and circularity were measured using an SEM and average values ​​were calculated for 100 or more particles using image analysis software (Asahi Kasei Engineering Co., Ltd.: A-zo-kun). Average particle diameter: The volume-average particle diameter was measured using a laser diffraction particle size analyzer (Malvern Panalytica, Mastersizer 3000), and D50 was used as the average particle diameter. Alkali metal content: The alkali metal content was measured using ICP atomic emission spectroscopy. As a result, the values ​​of all elements except Na were below the detection limit, so the Na content was measured.

[0035] The results are shown in Table 1.

[0036] As is clear from Table 1, in the test samples of the examples, the refractive index was measurable with sufficient transparency by setting the mass of Al to 45% or less (less than 50%) based on the sum of the masses of metallic aluminum (Al) and metallic silicon (Si), whereas in the test samples of Comparative Examples 1 to 3, the transparency was insufficient due to the high degree of crystallinity, and the refractive index could not be measured.

[0037] Furthermore, the refractive index could be increased by increasing the proportion of Al. Furthermore, the particulate silica of Example 1 of Patent Document 1 (Comparative Example 4) had a lower degree of crystallinity than Comparative Examples 1-3, and the refractive index could be measured, but the circularity was low and the Na content was high. Furthermore, the test sample of Comparative Example 5 was obtained by washing the test sample of Comparative Example 4 with water, but still had a high Na content, making it difficult to remove the Na.

Claims

1. A spherical composite oxide particle material composed of a composite oxide containing Si and Al, with an alkali metal content of 20 ppm or less and a crystallinity of 0.5% or less.

2. The spherical composite oxide particle material according to claim 1, wherein the mass of Al is less than 50% based on the mass of Si and Al, the number of moles of Al is 10% or more based on the number of moles of Si, the refractive index is 1.50±0.03, the circularity is 0.9 or more, and the volume average particle size is 0.1 μm or more and 20 μm or less.

3. A spherical complex oxide particulate material that can be produced by a method for producing a spherical complex oxide particulate material, the method comprising: a preparation step of preparing a raw particle material containing metallic silicon and metallic aluminum and having an alkali metal content of 20 ppm or less; and a deflagration and spheroidization step of introducing the raw particle material into a high-temperature oxidizing atmosphere, deflagrating it to form an oxide, and then rapidly cooling and spheroidizing it to form a spherical complex oxide particulate material having a crystallinity of 0.5% or less.

4. The spherical composite oxide particle material according to claim 1 or 3, wherein the mass of Al is less than 50% based on the mass of Si and Al.

5. The spherical composite oxide particle material according to any one of claims 1, 3 and 4, which has a refractive index of 1.50±0.

03.

6. The spherical composite oxide particle material according to any one of claims 1 and 3 to 5, wherein the number of moles of Al is 10% or more based on the number of moles of Si.

7. The spherical composite oxide particle material according to any one of claims 1 and 3 to 6, which has a circularity of 0.9 or more.

8. The spherical composite oxide particle material according to any one of claims 1 and 3 to 7, which has a volume average particle size of 0.1 μm or more and 20 μm or less.

9. The spherical composite oxide particle material according to any one of claims 1 to 8, which has been surface-treated with an organosilicon compound.

10. A slurry composition comprising: the spherical composite oxide particulate material according to any one of claims 1 to 9; and a dispersion medium for dispersing the spherical composite oxide particulate material.

11. A transparent resin composition comprising: the spherical composite oxide particle material according to any one of claims 1 to 9; and a transparent resin material in which the spherical composite oxide particle material is dispersed.

12. A method for producing a spherical composite oxide particulate material according to any one of claims 1 to 9, comprising: a preparation step of preparing a raw particle material containing metallic silicon and metallic aluminum and having an alkali metal content of 20 ppm or less; and a deflagration and spheroidization step of introducing the raw particle material into a high-temperature oxidizing atmosphere, deflagrating it to form an oxide, which is then rapidly cooled and spheroidized to produce a spherical composite oxide particulate material having a crystallinity of 0.5% or less.

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