JP6045875B2 - Method for producing surface-modified composite metal oxide fine particles - Google Patents

Description

  The present invention relates to composite metal oxide fine particles whose surface is modified with a silicon compound having a specific structure, and a method for producing the same.

  Conventionally, in the field of optical materials that require high transparency, acrylic resins and epoxy resins have been widely used. However, they absorb high-temperature environments or short-wavelength light, such as light-emitting diode (LED) encapsulants. Under such use conditions, there is a problem that the optical resin gradually deteriorates and yellowing or cracking occurs. Therefore, silicone resins having high heat resistance and light resistance are used in applications that require high durability. However, the silicone resin has a refractive index lower than that of a conventional optical resin. For example, when it is used as an LED sealing material or a lens, there is a problem that light utilization efficiency is lowered. Phenyl silicone having a higher refractive index is also used, but since the heat resistance and light resistance are reduced by introduction of the phenyl group, the range of use is limited.

  Therefore, a method of increasing the refractive index by dispersing an inorganic filler having a high refractive index in a silicone resin has been studied, and the development of a silicone resin in which metal oxides such as titanium oxide, zirconium oxide, and zinc oxide are dispersed has been developed. (For example, Patent Documents 1 to 3). Moreover, since the composite metal oxide represented by barium titanate has a higher refractive index, it can be said that it is preferable as an inorganic filler for the purpose of increasing the refractive index.

JP 2010-138270 A JP 2010-241935 A JP 2009-173866 A

  However, metal oxides such as titanium oxide, zirconium oxide, and zinc oxide are known to exhibit photocatalytic properties, and it is known that there is a concern of promoting deterioration of the resin depending on use conditions. On the other hand, the use of composite metal oxides typified by barium titanate has also been studied, but the fine particles are more cohesive than conventional metal oxides, and the dispersion is derived from metal components. It was difficult to impart dispersibility to the silicone resin by appropriate surface modification such as basicity.

  In view of the above situation, the present invention is capable of uniform dispersion in a silicone resin, and maintains surface transparency of the silicone resin and is suitable as an inorganic filler for increasing the refractive index. It is an issue to provide. Another object of the present invention is to provide a solution uniformly dispersed in an organic solvent and a cured product suitable as an optical material such as an LED sealant and a lens by using the surface-modified composite metal oxide fine particles.

  As a result of intensive studies to achieve the above object, the present inventors have found that the composite metal oxide fine particles surface-treated with a silicon compound having a specific structure can be uniformly dispersed in a silicone resin. And it discovered that it was useful as an inorganic filler aiming at physical property improvement, such as high refractive index, and completed this invention. That is, the present invention is as follows.

[1] On the surface of the composite metal oxide fine particles, the following general formula (1):
^{R 1 R 2 R 3 Si-} A-SiR 4 n X (3-n) (1)
{Wherein R ^{1 to} R ³ are each independently a hydrocarbon group having 1 to 18 carbon atoms or an optionally substituted siloxy group, and R ⁴ is a hydrocarbon group having 1 to 4 carbon atoms. A is a divalent hydrocarbon group having 2 to 6 carbon atoms, and X is a hydrogen atom, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a cycloalkoxy group having 3 to 6 carbon atoms, or An acetoxy group and n is 0 or 1; }
Surface-modified composite metal oxide fine particles having a structural site derived from a silicon compound represented by the formula:

  [2] The surface modified composite metal oxide fine particles according to [1], wherein the composite metal oxide fine particles have an average primary particle diameter of 1 nm or more and 40 nm or less.

  [3] The surface-modified composite metal oxide fine particles according to [1] or [2], wherein the composite metal oxide fine particles are barium titanate fine particles.

  [4] Any one of [1] to [3], including a step of adding the silicon compound represented by the general formula (1) to the uniform dispersion of the composite metal oxide fine particles containing alcohol and water. A method for producing the surface-modified composite metal oxide fine particles according to Item.

  [5] A uniform dispersion containing the surface-modified composite metal oxide fine particles according to any one of [1] to [3] and an organic solvent.

  [6] A step of curing a molded product obtained by molding the surface-modified composite metal oxide fine particles according to any one of [1] to [3] without using a solvent, or the method according to [5]. The manufacturing method of hardened | cured material including the process of hardening the thin film obtained by apply | coating the uniform dispersion liquid of this on a board | substrate.

  [7] A cured product obtained by the production method according to [6].

  According to the present invention, surface-modified composite metal oxide fine particles that can be uniformly dispersed in a silicone resin, are suitable as an inorganic filler for maintaining the transparency of the silicone resin and increasing the refractive index are provided. Further, by using the surface-modified composite metal oxide fine particles of the present invention, a highly transparent uniform dispersion liquid in which aggregation of the fine particles is suppressed is provided. Furthermore, a highly transparent and high refractive index cured product suitable as an optical material such as an LED sealant and a lens is provided.

It is a 1H-NMR spectrum of silicon compound S-1 used in an embodiment of the present invention. It is a 1H-NMR spectrum of silicon compound S-6 used in another embodiment of the present invention.

  Hereinafter, modes for carrying out the present invention (hereinafter abbreviated as “embodiments”) will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

The surface-modified composite metal oxide fine particles of the present embodiment have the following general formula (1):
^{R 1 R 2 R 3 Si-} A-SiR 4 n X (3-n) (1)
{Wherein R ^{1 to} R ³ are each independently a hydrocarbon group having 1 to 18 carbon atoms or an optionally substituted siloxy group, and R ⁴ is a hydrocarbon group having 1 to 4 carbon atoms. A is a divalent hydrocarbon group having 2 to 6 carbon atoms, and X is a hydrogen atom, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a cycloalkoxy group having 3 to 6 carbon atoms, or An acetoxy group and n is 0 or 1; }
The surface has a structural site derived from a silicon compound represented by the formula:
The surface-modified composite metal oxide fine particles can be obtained by surface-modifying the composite metal oxide fine particles using the silicon compound represented by the general formula (1).

<Silicon compound>
In the general formula ^(1), R 1 ~R ³ is a hydrocarbon group, or a substituted optionally may be siloxy group having 1 to 18 carbon atoms and may be the same or different. Examples of the hydrocarbon group having 1 to 18 carbon atoms include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylpropyl group, 1,1-dimethylpropyl group, 1,2-dimethylpropyl group, 2,2-dimethylpropyl group, Acyclic or cyclic saturated carbonization such as cyclopentyl group, n-hexyl group, cyclohexyl group, n-heptyl group, 2-methylhexyl group, n-octyl group, n-nonyl group, n-decyl group, octadecyl group, etc. Aromatic hydrocarbon group such as hydrogen group, phenyl group, tolyl group, xylyl group, vinyl group, propenyl group, butenyl group, pentenyl group, hexenyl group, cyclohexenyl group An acyclic and cyclic unsaturated hydrocarbon group such as a benzene group, a cyclohexenylethyl group, a norbornenylethyl group, a heptenyl group, an octenyl group, a nonenyl group, a decenyl group, and a styryl group, Examples thereof include arylalkyl groups such as 2-methylbenzyl group, 3-methylbenzyl group, 4-methylbenzyl group and the like. Examples of the optionally substituted siloxy group include trimethylsiloxy group, methyldiethylsiloxy group, dimethylethylsiloxy group, dimethylbutylsiloxy group, dimethylcyclohexylsiloxy group, dimethylphenylsiloxy group, methyldiphenylsiloxy group and the like. Can be mentioned.

Among these, from the viewpoint that the surface modification reaction with the composite metal oxide fine particles proceeds easily and suppresses the decrease in the refractive index due to the surface modification group, R ^{1 to} R ³ are methyl group, ethyl group, trimethylsiloxy. Or a dimethylphenylsiloxy group, more preferably a methyl group or a trimethylsiloxy group.

In the general formula (1), ^{R 4} is a hydrocarbon group having 1 to 4 carbon atoms. Examples of the hydrocarbon group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a sec-butyl group. Among these, R ⁴ is preferably a methyl group from the viewpoint that the surface modification reaction with the composite metal oxide fine particles easily proceeds.

  In the said General formula (1), A is a C2-C6 bivalent hydrocarbon group. As a C2-C6 bivalent hydrocarbon group, a C2-C6 linear or branched alkylene group etc. are mentioned, for example. Among these, from the viewpoint of ease of synthesis, A is preferably a linear or branched alkylene group having 2 or 3 carbon atoms, more preferably a linear or branched alkylene group having 2 carbon atoms. is there.

  In the silicon compound represented by the general formula (1), A in the general formula (1) greatly affects the reactivity and stability of the silicon compound. For example, in the surface modification reaction with the composite metal oxide fine particles described later, a reactive substituent on the same silicon atom {corresponds to X in the general formula (1). } And a siloxy group such as a trimethylsiloxy group, the hydrolysis reaction and condensation reaction of only the silicon compound proceed preferentially, and the target surface modification reaction does not proceed. The reason why the reactivity is so different is not clear, but it is considered that the decomposition reaction of the silicon compound proceeds due to the basicity derived from the surface hydroxyl group of the composite metal oxide fine particles.

  Moreover, 2 or more types of A in the general formula (1) may be mixed. As will be described later, as an example of the method for producing the silicon compound represented by the general formula (1), a hydrosilylation reaction between a corresponding hydrosilane compound and an alkenylsilane compound can be mentioned. In this reaction, generally, a mixture of cis-trans isomers is obtained as an addition product. it can.

In the above general formula (1), X is a hydrogen atom, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a cycloalkoxy group having 3 to 6 carbon atoms, or an acetoxy group. Examples of the halogen atom include fluorine, chlorine, bromine, iodine and the like. Moreover, as a C1-C6 alkoxy group, a methoxy group, an ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, t-butoxy group, n-hexyloxy group etc. are mentioned, for example. Moreover, as a C3-C6 cycloalkoxy group, a cyclohexyloxy group etc. are mentioned, for example.
Among these, from the viewpoint of easy reaction control, X is preferably a hydrogen atom or an alkoxy group, more preferably a hydrogen atom, a methoxy group, or an ethoxy group.

  In the general formula (1), n is 0 or 1. From the viewpoint that the surface modification reaction with the composite metal oxide fine particles easily proceeds, n is preferably 0 or 1.

  The silicon compound represented by the general formula (1) can be produced, for example, by a hydrosilylation reaction between a corresponding hydrosilane compound and an alkenylsilane compound. Specifically, in a hydrocarbon-based organic solvent or in the absence of a solvent, the hydrosilane compound and the alkenylsilane compound are dissolved so that the equimolar amount or one of the compounds is slightly excessive, and the metal catalyst is added and heated and stirred. It is manufactured by.

The hydrosilane compound and alkenylsilane compound correspond to the silicon compound represented by the general formula (1), and the following general formula (2):
R ¹ R ² R ³ Si—H (2)
{In the formula, R ^{1 to} R ³ are as defined in the general formula (1), but exclude an unsaturated hydrocarbon group. }
And the following general formula (3):
B-SiR ⁴ _n X _(3-n) (3)
{Wherein R ⁴ , X and n are as defined in the general formula (1), X is a hydrogen atom and B is an unsaturated hydrocarbon group having 2 to 6 carbon atoms. It is. }
An alkenylsilane compound represented by:
Or the following general formula (4):
R ¹ R ² R ³ Si-B (4)
{Wherein R ^{1 to} R ³ are as defined in the general formula (1), and B is an unsaturated hydrocarbon group having 2 to 6 carbon atoms. }
And an alkenylsilane compound represented by the following general formula (5):
_{^{H-SiR 4 n X (3}} -n) (5)
{Wherein R ⁴ , X and n are as defined in the general formula (1). }
The hydrosilane compound represented by these can be used in combination.
B in the general formulas (3) and (4) is an unsaturated hydrocarbon group having 2 to 6 carbon atoms. In B, the position of the unsaturated bond, the three-dimensional structure, and the presence or absence of a branched structure are not particularly limited, but B is preferably a vinyl group or an allyl group from the viewpoint of availability of raw materials or ease of synthesis. .

  Although there is no restriction | limiting in particular in the molar ratio of the said hydrosilane compound and an alkenylsilane compound, Generally, an alkenylsilane compound should be used in 0.9-1.1 mol with respect to 1 mol of hydrosilane compounds. Is preferred.

  Examples of the hydrocarbon organic solvent include hydrocarbon organic solvents such as hexane, octane, toluene, and xylene. The organic solvent can be used in any amount.

  Examples of the metal catalyst include platinum group metals such as platinum, palladium, rhodium, and ruthenium, supported catalysts in which the platinum group metal is supported on a carrier such as carbon, alumina, silica, and polymer, chloroplatinic acid, and alcohol-modified platinum chloride. Examples include acids, olefins or acetylene complexes of chloroplatinic acid, vinylsiloxane complexes of platinum, tetrakis (triphenylphosphine) palladium, and chlorotris (triphenylphosphine) rhodium. Among these, chloroplatinic acid (Speier catalyst), platinum tetramethyldivinyldisiloxane complex (Karsttedt catalyst), and chlorotris (triphenylphosphine) rhodium (Wilkinson catalyst) are preferable. These metal catalysts may be used alone or in combination of two or more.

The usage-amount of the said metal catalyst can be used in the range of 1 * 10 < ^-6 > -0.01 mol with respect to 1 mol of said hydrosilane compounds.

  The reaction temperature of the hydrosilylation reaction is preferably in the range of 0 to 150 ° C., and the reaction time is preferably in the range of 0.5 to 48 hours.

  When the silicon compound represented by the general formula (1) is synthesized by the hydrosilylation reaction, a cis isomer and a trans isomer are formed when the hydrosilane is added to the unsaturated bond site of the alkenyl silane, and a mixture of these isomers. May be obtained. This isomer mixture can be separated by a separation operation such as distillation or column chromatography. However, even if it is a cis-trans isomer mixture, it is preferably used in the surface modification reaction with the composite metal oxide fine particles described later. can do.

  Among the silicon compounds represented by the general formula (1), for the silicon compound in which X in the general formula (1) is a hydrogen atom, for example, X in the general formula (1) is a halogen atom, an alkoxy group, A silicon compound which is a cycloalkoxy group or an acetoxy group can be produced by the above-described method and then subjected to a reduction reaction using a reducing agent such as lithium aluminum hydride or sodium borohydride.

<Composite metal oxide fine particles>
In the present embodiment, the composite metal oxide fine particles are composed of composite metal oxide fine particles containing two or more kinds of metal atoms and oxygen atoms. Examples of the composite metal oxide include barium titanate, strontium titanate, lead titanate, zirconium silicate, lead zirconate, indium tin oxide, antimony tin oxide, lithium niobate, and lithium cobaltate. Among these, from the viewpoint of improving the refractive index, barium titanate and strontium titanate are preferable. These may be used alone or in combination of two or more.

  The composite metal oxide fine particles are preferably spherical, rod-shaped, plate-shaped or fibrous, or a shape in which two or more of these are combined, and more preferably spherical. In addition, the spherical shape here means a substantially spherical shape including a spheroid, an oval and the like in addition to a true spherical shape.

  The average primary particle diameter of the composite metal oxide fine particles is preferably equal to or less than the wavelength of light used in the intended application in order to avoid adverse effects on transparency due to light scattering. The average primary particle diameter is preferably 1 nm or more and 100 nm or less, more preferably 1 nm or more and 40 nm or less. If the average primary particle diameter is 1 nm or more, the dispersibility of the composite metal oxide fine particles is good, and if it is 100 nm or less, the transparency when dispersed in an organic solvent or resin is good. In the present disclosure, the average primary particle diameter means a number average value. The average primary particle diameter can be determined by direct observation with a transmission electron microscope (TEM).

The composite metal oxide fine particles can be produced by a hydrothermal method, a sol-gel method, a coprecipitation method, or the like, and the average primary particle size can be controlled by changing the production conditions.
About the specific manufacturing method of the composite metal oxide fine particles, for example, in the case of barium titanate, in 2-methoxyethanol, after equimolar amounts of metal barium and tetraethyl orthotitanate are heated and dissolved, Examples thereof include a method in which a hydrolysis reaction and a condensation reaction are advanced by adding water to obtain a dispersion of barium titanate fine particles. If necessary, powdery barium titanate fine particles can be obtained by performing a drying treatment such as spray drying or vacuum drying. In addition, by performing the sintering process in an electric furnace or the like, the surface hydroxyl group amount of the barium titanate fine particles can be controlled according to the sintering process time.

<Surface treatment>
In the present embodiment, the surface-modified composite metal having a structure portion derived from the silicon compound on the surface by causing the silicon compound represented by the general formula (1) to act on the composite metal oxide fine particles to perform a surface modification reaction. A method for producing oxide particulates is disclosed.

  Specifically, for example, it is produced by a step of adding the silicon compound to a uniform dispersion of composite metal oxide fine particles containing alcohol and water. The alcohol that can be used is preferably an alcohol having 1 to 4 carbon atoms from the viewpoint of easy mixing with water, for example, methanol, ethanol, n-propanol, 2-propanol, n-butanol, methoxyethanol, ethoxyethanol. Etc.

  The uniform dispersion may contain water used in the hydrolysis step when producing the composite metal oxide fine particles as it is, and by removing a part or adding water, the water content can be reduced. It can also be controlled. The silicon compound may be added as it is, or may be added after diluting with alcohol, water or other organic solvent.

  The reaction temperature for the surface modification reaction is preferably 0 ° C to 120 ° C, more preferably 30 ° C to 100 ° C. The reaction time is preferably 0.5 hours to 24 hours, more preferably 0.5 hours to 3 hours.

  The composite metal oxide fine particles used for the surface modification reaction may be dispersed in water, an organic solvent, or a mixture thereof, or may be a powder obtained by a drying treatment. When the surface modification reaction is performed using the powdered composite metal oxide fine particles, the surface modification reaction may be performed in a dispersion apparatus such as a bead mill.

  The bead mill is a dispersing device including a bead separation mechanism that separates beads, which are a rotor, a stator, and stirring particles. The beads that are stirring particles are required to be ultrafine beads, and the particle diameter is preferably 3 μm to 300 μm, more preferably 10 μm to 50 μm. If the particle diameter is 3 μm or more, impact energy required for dispersion can be obtained, and if it is 300 μm or less, reaggregation due to excessive impact energy can be suppressed.

Examples of the stirring particles include zirconia, alumina, silica, glass, silicon carbide, and silicon nitride. Among these, zirconia is preferable from the viewpoint of excellent strength and stability as stirring particles.
In the surface modification reaction, the reactive functional group X of the silicon compound represented by the general formula (1) and the surface hydroxyl group (M-OH) of the composite metal oxide fine particle undergo a condensation reaction, thereby sharing via an oxygen atom. A bond (M-O-Si) is generated.
The presence or absence of a covalent bond (MO—Si) via an oxygen atom can be confirmed by detecting an absorption peak derived from the covalent bond with a transmission type or diffuse reflection type infrared spectroscopic device.

<Uniform dispersion>
Another aspect of the present embodiment provides a uniform dispersion containing the surface-modified composite metal oxide fine particles and an organic solvent. The organic solvent is preferably one that can uniformly disperse the composite metal oxide fine particles. Further, when a resin, a dispersant, a storage stabilizer or the like is added, the organic solvent has high solubility in those additives. It is preferable to have.

Examples of the organic solvent include one or more solvents selected from alcohols, ketones, esters, ethers, and hydrocarbon solvents.
Examples of the alcohol, ketone, ester, ether, and hydrocarbon solvent include alcohols such as butanol, pentanol, hexanol, octanol, methoxyethanol, ethoxyethanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether; methyl ethyl ketone, Ketones such as methyl isobutyl ketone, isoamyl ketone, ethyl hexyl ketone, cyclopentanone, cyclohexanone, γ-butyrolactone; butyl acetate, pentyl acetate, hexyl acetate, propyl propionate, butyl propionate, pentyl propionate, hexyl propionate Esters, propylene glycol monomethyl ether acetate, ethyl lactate, etc .; butyl ethyl ether, butyl propyl ether Ethers such as toluene, dibutyl ether, anisole, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, and tetrahydrofuran; hydrocarbon solvents such as hexane, heptane, octane, decane, cyclohexane, toluene, xylene, etc. Can be mentioned. These solvents may be used alone or in combination of a plurality of solvents.

<Hardened product>
Another aspect of the present embodiment is a step of curing a molded body obtained by molding the surface-modified composite metal oxide fine particles without using a solvent, or applying the uniform dispersion on a substrate. The manufacturing method of hardened | cured material including the process of hardening the thin film obtained by this is provided.

  The said molded object is obtained by shape | molding the composite metal oxide by which surface treatment was carried out using metal, resin, or metal mold | dies, sheets, stamps, etc .. The thin film can be obtained by applying the uniform dispersion on a substrate. A pattern shape such as a concave shape, a convex shape, a fine lens shape, and a fine periodic structure can be imparted to the surface of the molded body and the thin film.

  By curing the surface-modified composite metal oxide fine particles or the thin film using heat or light, a transparent cured product preferable as an optical material can be obtained.

  The curing temperature in the case of performing the curing process with heat is preferably 30 ° C to 300 ° C, and more preferably 70 ° C to 200 ° C. The curing time is preferably 10 minutes to 12 hours, more preferably 10 minutes to 3 hours. The curing treatment by heat may be performed in the air or in an inert gas atmosphere such as nitrogen, helium, argon or the like.

  In the case of performing a curing treatment with light, for example, visible light, ultraviolet light, far ultraviolet light, or the like can be used. Examples of the light source include a low-pressure or high-pressure mercury lamp, deuterium lamp, or discharge light of a rare gas such as argon, krypton, or xenon, YAG laser, argon laser, carbon dioxide laser, or XeF, XeCl, XeBr, KrF, An excimer laser such as KrCl, ArF or ArCl can be used. The output of these light sources is preferably 10 to 5,000 W.

  Yet another aspect of the present embodiment provides a cured product obtained by the above production method. The said hardened | cured material can be utilized suitably as optical materials, such as a sealing agent and a lens in a light emitting element.

Hereinafter, although an embodiment and a comparative example explain this embodiment in detail, this embodiment is not limited to these.
In addition, the physical property in each manufacture example, an Example, and a comparative example was measured with the following method.

(1) Confirmation method of crystal structure A sample obtained by drying a powder of composite metal oxide fine particles or a dispersion liquid was measured using an X-ray diffraction (XRD) apparatus, D8 ADVANCE manufactured by Nippon Bruker Co., Ltd. The crystal structure was confirmed by comparing with the diffraction pattern.

(2) Calculation method of average primary particle diameter A dispersion liquid of composite metal oxide fine particles is dropped on a membrane for collecting a fine sample (collodion membrane) and dried, and then a transmission electron microscope manufactured by Hitachi High-Technologies Corporation ( FE-TEM) and HF-2000 were used to measure the primary particle size at an acceleration voltage of 200 kV, and the average primary particle size was calculated from the number average of 50 particles.

(3) Tracking reaction by gas chromatography (GC) The reaction mixture was measured by gas chromatography (GC), and the signal intensity of the peak derived from the raw material was recorded. The amount of raw material contained in the reaction mixture was calculated using a separately prepared calibration curve.
[GC measurement conditions]
-GC device: GC-14B (manufactured by Shimadzu Corporation)
Column: DB-1 (30 m × 250 μm × 0.25 μmF) (manufactured by Agilent Technologies)
Column temperature: Hold for 5 minutes at 50 ° C., then increase to 300 ° C. by 10 ° C. per minute. Carrier gas: He (flow rate: 1.0 mL / min)

(4) Measurement of proton nuclear magnetic resonance (1H-NMR) spectrum The proton nuclear magnetic resonance (1H-NMR) spectrum of the resulting solution was dissolved in deuterated chloroform so that the concentration of the silicon compound was 5% by mass. Was measured by integrating 16 times using an FT-NMR apparatus, AVANCE400 manufactured by Nippon Bruker Co., Ltd.

(5) Measurement of weight average molecular weight (Mw) Gel permeation chromatography is obtained by diluting an isopropyl alcohol solution of a silicone resin or a propylene glycol methyl ether acetate solution with tetrahydrofuran so that the concentration of the silicone resin component becomes 1% by mass. Measured by graphic (GPC). The weight average molecular weight (Mw) was determined as a value in terms of polystyrene as a standard substance.
[GPC measurement conditions]
-Column: TSKgel G1000H-HR, G3000H-HR, and G5000H-HR (all manufactured by Tosoh Corporation) in series-Eluent: Tetrahydrofuran (flow rate: 1 mL / min)
Column operating temperature: 40 ° C

(6) Method for calculating surface modification rate 1.0 g of powder of composite metal oxide fine particles with surface modification and 2.0 g of crystalline cellulose (trade name: Avicel, manufactured by Funakoshi) were mixed and stirred in an automatic agate mortar for 30 minutes. . The obtained powder is filled into a 25 mmφ vinyl chloride ring, a sample is prepared with a tablet molding machine, and FP order analysis is performed using a Rigaku scanning X-ray fluorescence analyzer, ZSX Primus II. The molar ratio of silicon atoms was measured, and the amount of silicon compound present on the surface of the composite metal oxide fine particles was calculated.
When the surface area of the composite metal oxide fine particles is calculated from the average primary particle diameter and the occupied area per molecule of the silicon compound is 1.3 × 10 ⁻¹⁹ m ² , the entire surface of the composite metal oxide fine particles is The coated state was defined as a surface modification rate of 100%, and the state in which no silicon compound was present was defined as a surface modification rate of 0%.

(7) Evaluation of dispersibility in organic solvent and silicone resin In a 20 mL sample tube, 0.5 g of surface-modified composite metal oxide fine particles and 4.5 g of toluene were placed and subjected to ultrasonic treatment. Regarding the dispersibility in an organic solvent, ○ was obtained when it was dissolved in toluene to form a transparent uniform dispersion, Δ if it was not dispersed and settled but was cloudy, and × was not dissolved.
Further, 0.5 g of surface-modified composite metal oxide fine particles, 4.5 g of the silicone resin obtained in Production Example 10 below, and 100 g of toluene were added to a 300 mL flask and stirred to obtain a uniform dispersion. While heating in a water bath set at 70 ° C., the solvent was distilled off by an evaporator to prepare a silicone resin in which composite metal oxide fine particles were dispersed. The composite metal oxide fine particles are uniformly dispersed in the silicone resin, and the transparency is maintained as ◯, the transparency is maintained but turbid as △, and the white turbidity due to phase separation is transparent. The thing which lost the property was set as x.

<Method for producing fine barium titanate particles>
[Production Example 1]
A 1 L separable flask equipped with a reflux tube, a dropping funnel and a stirrer was replaced with a nitrogen atmosphere, and then 120.3 g of 2-methoxyethanol (ME), 2.75 g of metal barium, and 4.19 mL of tetraethoxytitanium were added and stirred. The mixture was heated at 120 ° C. for 2 hours. A mixture of ME 102.9 g and ion-exchanged water 18.0 g was added dropwise, and heating and stirring were continued at 120 ° C. for 3 hours to obtain a barium titanate dispersion (BT-1). In the XRD measurement, it was confirmed that it coincided with the diffraction pattern of barium titanate. Moreover, in the TEM measurement, the average primary particle diameter of BT-1 was about 7 nm.

[Production Example 2]
A barium titanate fine particle dispersion (BT-2) was obtained in the same manner as in Production Example 1 except that 36.0 g of ion-exchanged water was used. In the XRD measurement, it was confirmed that it coincided with the diffraction pattern of barium titanate. Moreover, in the TEM measurement, the average primary particle diameter of BT-2 was about 14 nm.

[Production Example 3]
A 2 L separable flask equipped with a reflux tube, a dropping funnel and a stirrer was replaced with a nitrogen atmosphere, and then 855 mL of ethanol, 24.7 g of barium metal and 37.7 mL of tetraethoxytitanium were added and heated at 70 ° C. for 2 hours with stirring. did. A mixture of 576 mL of ethanol and 324 mL of ion exchange water was added dropwise, and heating was continued at 70 ° C. for 3 hours to obtain an ethanol suspension of barium titanate fine particles.
The suspension was treated at 8,000 rpm for 30 minutes using a centrifuge to remove ethanol and water and separate the solids. This solid content was washed with ethanol and then dried under reduced pressure for 8 hours with a 70 ° C. vacuum dryer to obtain barium titanate fine particle powder (BT-3). In the XRD measurement, it was confirmed that it coincided with the diffraction pattern of barium titanate. Moreover, in the TEM measurement, the average primary particle diameter of BT-3 was about 7 nm.

<Method for producing silicon compound>
[Production Example 4]
After replacing a 2 L separable flask equipped with a reflux tube and a stirrer with a nitrogen atmosphere, 800 g of dehydrated toluene, 128.6 g of 1,1,1,3,5,5,5-heptamethyltrisiloxane, trimethoxyvinylsilane 71 .4 g and 110 μL of a 2% by mass xylene solution of platinum tetramethyldivinyldisiloxane complex (Karstedt catalyst) were added, and the mixture was heated and stirred at 60 ° C. for 8 hours until the peak of the starting material trimethoxyvinylsilane disappeared in gas chromatography. . After evaporating toluene under reduced pressure with an evaporator, the desired 1,1,1,3,5,5,5-heptamethyl-2- (2-trimethoxysilylethyl) trisiloxane (S-1) was obtained by distillation under reduced pressure. Obtained. The boiling point of S-1 was 103 ° C. at 0.57 kPa. A 1H-NMR chart of S-1 is shown in FIG.

[Production Example 5]
The target (2-trimethylsilylethyl) triethoxysilane (S-2) was obtained in the same manner as in Production Example 4 except that trimethylvinylsilane and triethoxysilane were used as raw materials.

[Production Example 6]
The target pentamethyl (2-trimethoxysilylethyl) is prepared in the same manner as in Production Example 4 except that pentamethyldisiloxane is used instead of 1,1,1,3,5,5,5-heptamethyltrisiloxane. Disiloxane (S-3) was obtained.

[Production Example 7]
The target tris (trimethylsiloxy) (2) was prepared in the same manner as in Production Example 4 except that tris (trimethylsiloxy) silane was used instead of 1,1,1,3,5,5,5-heptamethyltrisiloxane. -Trimethoxysilylethyl) silane (S-4) was obtained.

[Production Example 8]
The desired 1,1,3,5,5,5-heptamethyl-2- (2-methyldimethoxysilylethyl) is prepared in the same manner as in Production Example 4 except that methyldimethoxyvinylsilane is used instead of trimethoxyvinylsilane. Trisiloxane (S-5) was obtained.

[Production Example 9]
A 1 L flask equipped with a reflux tube, a dropping funnel and a stirrer was replaced with a nitrogen atmosphere, and then 3.8 g of lithium aluminum hydride and 200 mL of ultra-dehydrated diethyl ether were added while cooling with ice water. To this solution, a mixture of 26.4 g of the silicon compound (S-1) synthesized in Production Example 4 above and 50 mL of ultra-dehydrated diethyl ether was added dropwise so that the internal temperature of the flask did not exceed 15 ° C. Stir for hours. In gas chromatography, after confirming that the peak of S-1 as a raw material had disappeared, it was cooled again with ice water, and 17.6 g of ethyl acetate was added dropwise so that the internal temperature of the flask did not exceed 15 ° C. Stir at room temperature for 8 hours. The reaction solution was filtered under reduced pressure using Celite 545, and then diethyl ether and excess ethyl acetate were distilled off under reduced pressure using an evaporator. The desired 1,1,1,3,5,5,5-heptamethyl-2- (2-trihydrosilylethyl) trisiloxane (S-6) was obtained by distillation under reduced pressure. The boiling point of S-6 was 58 ° C. at 0.5 kPa. A 1H-NMR chart of S-6 is shown in FIG.

<Manufacturing method of silicone resin>
[Production Example 10]
In a 1 L separable flask equipped with a reflux tube, a dropping funnel, and a stirrer, 149.9 g of methyltrimethoxysilane, 32.5 g of ethoxytrimethylsilane, and 120 g of isopropyl alcohol (IPA) were added and stirred. A mixture with 128.7 g of ion-exchanged water was added dropwise and heated in an oil bath set at 80 ° C. for 2 hours to obtain a reaction mixture.
The reaction mixture was transferred to a 1 L flask, 360 g of propylene glycol methyl ether acetate (PGMEA) was added, and IPA and water were distilled off with an evaporator. Furthermore, it concentrated until the silicone resin component became 33.3 mass%, and the PGMEA solution of silicone resin was obtained. The weight average molecular weight (Mw) of the obtained silicone resin was 957.
Into a 1 L separable flask equipped with a reflux tube, a dropping funnel, and a stirrer prepared separately, 288 g of the above PGMEA solution of silicone resin, 90.1 g of pyridine, and 100 g of PGMEA were stirred, and further 68.8 g of vinyldimethylchlorosilane and trimethyl were added. A mixture of 62.0 g of chlorosilane was added dropwise and stirred at room temperature for 1 hour.
After adding 100 g of cyclohexane and 100 g of ion-exchanged water, the aqueous layer was removed by a liquid separation operation, and the obtained organic layer was washed twice with 100 g of ion-exchanged water. The organic solvent was distilled off with an evaporator to obtain 146 g of the desired silicone resin. The weight average molecular weight (Mw) of the obtained silicone resin was 2,092.

<Surface modification reaction>
[Example 1]
A white suspension is obtained by adding 3.31 g of the silicon compound (S-1) to the dispersion (BT-1) of the barium titanate fine particles obtained in Production Example 1 and heating at 70 ° C. for 1 hour. was gotten. The solvent was removed by treating at 7,000 rpm for 30 minutes using a centrifuge, and the resulting solid component was washed with acetone and ethanol, and then vacuum-dried at 40 ° C. to achieve the desired surface modification. Barium titanate fine particles (P-1) were obtained. The surface modification rate of P-1 was 29%.

[Example 2]
The target surface-modified barium titanate fine particles (P-2) were obtained in the same manner as in Example 1 except that S-2 was used instead of S-1.

[Example 3]
The target surface-modified barium titanate fine particles (P-3) were obtained in the same manner as in Example 1 except that S-3 was used instead of S-1.

[Example 4]
The target surface-modified barium titanate fine particles (P-4) were obtained in the same manner as in Example 1 except that S-4 was used instead of S-1.

[Example 5]
The target surface-modified barium titanate fine particles (P-5) were obtained in the same manner as in Example 1 except that S-5 was used instead of S-1.

[Example 6]
The target surface-modified barium titanate fine particles (P-6) were obtained in the same manner as in Example 1 except that S-6 was used instead of S-1.

[Example 7]
The target surface-modified barium titanate fine particles (P-7) were obtained in the same manner as in Example 1 except that BT-2 was used instead of BT-1.

[Example 8]
A 1 L separable flask equipped with a reflux tube and a stirrer was charged with 10 g of the barium titanate fine particle powder (BT-3) obtained in Production Example 3 above, 323 g of toluene, and 8.02 g of a silicon compound (S-6). The mixture was heated and stirred for 1 hour in an oil bath set to 40 ° C.
This reaction liquid was put into a tank of a bead mill (UAM-015, manufactured by Kotobuki Industries Co., Ltd.), and 100 g of toluene was added. By subjecting 350 g of zirconia beads having a particle size of 15 μm (DZB, model number φ15, manufactured by Daiken Chemical Industry Co., Ltd.) to dispersion treatment under conditions of a rotor rotation speed of 12 m / sec and a flow rate of 70 mL / min, the desired surface modification A toluene dispersion (P-8) of the barium titanate fine particles thus obtained was obtained. The surface modification rate of P-8 was 90%.

[Comparative Example 1]
The barium titanate fine particle powder (BT-3) obtained in Production Example 3 was directly used as P-9 without surface modification.

[Comparative Example 2]
The target surface-modified barium titanate fine particles (P-10) were obtained in the same manner as in Example 1 except that decyltrimethoxysilane was used instead of S-1.

[Comparative Example 3]
The target surface-modified barium titanate fine particles (P-11) were obtained in the same manner as in Example 1 except that vinyltrimethoxysilane was used instead of S-1.

[Comparative Example 4]
The target surface-modified barium titanate fine particles (P-12) were obtained in the same manner as in Example 1 except that (3-methylmethacryl) propyltrimethoxysilane was used instead of S-1.

[Comparative Example 5]
An insoluble gel-like product was obtained in the same manner as in Example 1 except that methyltrimethoxysilane was used instead of S-1.

[Comparative Example 6]
Example 1 was used except that 1,1,1-trimethyl-3,3,3-trimethoxydisiloxane (abbreviated as “trimethylsiloxytrimethoxysilane” in Table 1) was used instead of S-1. An insoluble gel product was obtained.

<Evaluation of dispersibility in organic solvent and silicone resin>
Table 1 shows the results of evaluation of dispersibility in organic solvents and silicone resins for the composite metal oxide fine particles P-1 to P-14 obtained in Examples 1 to 8 and Comparative Examples 1 to 6.

  The composite metal oxide fine particles of the present invention can be suitably used as a raw material for a highly transparent and high refractive index organic-inorganic composite resin that can be used as an optical material such as a lens, a sealing material, and a coating agent.

Claims (5)

In the uniform dispersion of the composite metal oxide fine particles containing alcohol and water, the following general formula (1):
^{R 1 R 2 R 3 Si-} A-SiR 4 n X (3-n) (1)
{Wherein R ^{1 to} R ³ are each independently a hydrocarbon group having 1 to 18 carbon atoms or an optionally substituted siloxy group, and R ⁴ is a hydrocarbon group having 1 to 4 carbon atoms. A is a divalent hydrocarbon group having 2 to 6 carbon atoms, and X is a hydrogen atom, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a cycloalkoxy group having 3 to 6 carbon atoms, or An acetoxy group and n is 0 or 1; }
Including a step of adding a silicon compound represented by:
Wherein the surface of the composite metal oxide particles, having a front following general formula (1) structural site derived from the silicon compound represented by the surface modification method of producing a composite metal oxide fine particles. The method for producing surface-modified composite metal oxide fine particles according to claim 1, wherein an average primary particle diameter of the composite metal oxide fine particles is 1 nm or more and 40 nm or less. The method for producing surface-modified composite metal oxide fine particles according to claim 1, wherein the composite metal oxide fine particles are barium titanate fine particles. The said surface modification composite metal including the process of disperse | distributing the surface modification composite metal oxide fine particle obtained by the manufacturing method of the surface modification composite metal oxide fine particle of any one of Claims 1-3 to an organic solvent uniformly method for producing a homogeneous dispersion comprising fine oxide particles and the organic solvent. The molded object obtained by shape | molding the surface modification composite metal oxide fine particle obtained by the manufacturing method of the surface modification composite metal oxide fine particle of any one of Claims 1-3 without using a solvent is hardened. The manufacturing method of hardened | cured material including the process of apply | coating the uniform dispersion liquid obtained by the process or the manufacturing method of the uniform dispersion liquid of Claim 4 on a board | substrate, and hardening the thin film obtained.

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