JP2020164370A - Complex oxide and method for producing the same - Google Patents

Abstract

To provide an Al-Si-Ti complex oxide in which optical activity is inhibited.SOLUTION: A complex oxide of Al, Si, and Ti satisfies the following requirements (1) to (3): (1) an Al content (in Al2O3 conversion) is 60 mass% or more, an Si content (in SiO2 conversion) is 1.0 to 10 mass%, and Ti content ( in TiO2 conversion) is 12 to 30 mass%; (2) an absorption edge wavelength of the absorption peak, measured by the ultraviolet-visible spectral analysis is 350 nm or less; and (3) the following formula is satisfied:ΔLAS=LAS150-LAS250≥190 μmol/g, wherein LAS150 and LAS250 is the amount at Lewis acid point per unit mass of the complex oxide, measured by infrared spectroscopy, or is the amount at the Lewis acid point when exhaust gas temperatures after pyridine adsorption are each 150°C and 250°C in the production of a measurement sample.SELECTED DRAWING: Figure 2

Description

The present invention relates to a composite oxide of aluminum, silicon and titanium (also referred to as "Al-Si-Ti composite oxide" in the present invention) and a method for producing the same.

Conventionally, Al-Si-Ti composite oxide particles have been used as a filler (additive) for improving coating film strength in a paint, as a hard disk abrasive (Patent Document 1), and as a cosmetic using a refractive index (Patent Document 1). Patent Document 2), as a catalyst (catalyst carrier agent) that directly or indirectly utilizes the surface solid acid in the reaction (Patent Documents 3 to 5), a heat resistant agent that utilizes heat resistance, and a material for a fuel cell (Patent Document 2). It is widely used as Patent Document 6).

As a method for producing the same, for example, Patent Documents 3 and 5 describe a first aqueous solution containing a titanium mineral salt and an acidic aluminum salt and a second aqueous solution containing a basic aluminum salt in the presence of silicate ions. It includes a step of mixing so as to have a pH of 6.5 to 9.5 to obtain a slurry of hydrate, and a step of calcining the hydrate to obtain a carrier made of an Al—Si—Ti composite oxide. The manufacturing method is disclosed.

Japanese Unexamined Patent Publication No. 2012-200832 JP-A-10-236928 Japanese Unexamined Patent Publication No. 2011-072928 Japanese Unexamined Patent Publication No. 2004-33819 JP-A-2018-167196 Japanese Unexamined Patent Publication No. 2005-197242

The Al—Si—Ti composite oxide of the prior art has room for further improvement from the viewpoint of suppressing photoactivity.
Therefore, an object of the present invention is to provide an Al—Si—Ti composite oxide in which photoactivity is further suppressed (hereinafter, also simply referred to as “composite oxide”), and a method for producing the same.

The present invention relates to the following [1] to [7].
[1]
A composite oxide of aluminum, silicon and titanium that meets the following requirements (1) to (3).
Requirement (1): Aluminum content is 60% by mass or more in terms of Al ₂ O ₃ , silicon content is 1.0 to 10% by mass in terms of SiO ₂ , and titanium content is TiO ₂ It is 12 to 30% by mass in terms of conversion.
Requirement (2): The absorption edge wavelength of the absorption peak measured by ultraviolet spectroscopic analysis is 350 nm or less.
Requirement (3): Satisfy the following formula.
ΔLAS = LAS ₁₅₀ -LAS ₂₅₀ ≧ 190 μmol / g
[In the formula, LAS ₁₅₀ and LAS ₂₅₀ are the amounts of Lewis acid points per unit mass of the composite oxide measured by infrared spectroscopy using pyridine as a probe molecule, and are used in the preparation of measurement samples. It is the amount of Lewis acid points when the exhaust temperature after pyridine adsorption is 150 ° C. and 250 ° C., respectively. ]

[2]
The composite oxide of the above [1], wherein the diffraction peak showing the crystal structure of the anatase type titania (101) plane and the rutile type titania (110) plane is not detected by the X-ray diffraction analysis.

[3]
The composite oxide of the above [1] or [2] having a specific surface area of 280 m ² / g or more and a pore volume of 0.45 ml / g or more.

[4]
The composite oxide according to any one of [1] to [3], wherein the value of ΔLAS per unit specific surface area is 0.50 to 0.70 μmol / m ² .

[5]
A method for producing a composite oxide of aluminum, silicon and titanium.
A first aqueous solution containing a mineral acid and a titanium mineral salt compound containing the basic component of the mineral acid and a second aqueous solution containing a basic aluminum salt are mixed in the presence of silicate ions to pH 6 The first step of obtaining a mixed solution of .5-9.5 and precipitating a precursor of the composite oxide, and the first step of separating the precursor from the mixed solution and then heat-treating to obtain the composite oxide. A method for producing a composite oxide, which comprises two steps.

[6]
In the first aqueous solution, the value of (amount of substance of titanium mineral acid compounds (converted to the amount of substance of titanium)) / (amount of substance of mineral acid) is 0.15 to 0.70, the above [5]. Method for producing composite oxides.

[7]
The method for producing a composite oxide according to the above [5] or [6], wherein the first aqueous solution is prepared at 60 ° C. or lower.

Since the composite oxide of the present invention has substantially no aggregation of titania and ΔLAS is in a predetermined range, the photoactivity is low even though it contains a titania component. Therefore, the composite oxide of the present invention can be used as an optical material, or can be applied to cosmetics, resin fillers, additives for surface coating materials (for the purpose of optical scattering, refractive index adjustment, etc.) and the like.

Furthermore, according to the production method of the present invention, the composite oxide of the present invention exhibiting the above-mentioned effects can be produced.

FIG. 1 is an ultraviolet visible light diffuse reflection spectrum of the Al—Si—Ti composite oxide particles produced in Example 1 and Comparative Example 5. FIG. 2 is an X-ray diffraction spectrum of the Al—Si—Ti composite oxide particles produced in Example 1 and Comparative Example 5.

Hereinafter, the present invention will be described in more detail.
[Composite oxide]
The composite oxide of the present invention (also referred to as "Al-Si-Ti composite oxide" in the present invention) is a composite oxide of aluminum, titanium and silicon, and the requirements (1) to be described below. (3) is satisfied.

<< Requirements (1) >>
The content of aluminum in the Al—Si—Ti composite oxide of the present invention (the amount of the Al—Si—Ti composite oxide is 100% by mass; the same applies hereinafter) is 60 in terms of Al ₂ O ₃ . It is mass% or more, the silicon content is 1.0 to 10% by mass in terms of SiO ₂ , and the titanium content is 12 to 30% by mass in terms of TiO ₂ .

The content of aluminum is preferably 65% by mass or more, more preferably 70% by mass or more, from the viewpoint of further increasing the strength of the Al—Si—Ti composite oxide.
The content of the above silicon is preferably 1.5% by mass or more, and more preferably 2.0% by mass or more. Further, from the viewpoint of making the pore diameter uniform when the Al—Si—Ti composite oxide is porous, the silicon content is preferably 7.0% by mass or less, more preferably 5. It is 0.0% by mass or less.

The titanium content is preferably 15.0% by mass or more, and more preferably 18.0% by mass or more. Further, from the viewpoint of effectively suppressing the aggregation of TiO _{2 in} the Al—Si—Ti composite oxide, the Ti content is preferably 28.0% by mass or less, more preferably 25. It is 0% by mass or less.

<< Requirements (2) >>
In the Al—Si—Ti composite oxide particles of the present invention, the absorption edge wavelength of the absorption peak (this peak is derived from Titania) measured by ultraviolet spectroscopic analysis is 350 nm or less. The absorption edge wavelength of 350 nm or less means that the dispersibility of the titania component in the Al—Si—Ti composite oxide is good. From this point of view, the absorption edge wavelength is preferably 345 nm or less. On the other hand, the lower limit of the absorption edge wavelength is not particularly limited, but from the viewpoint of ensuring a sufficient Ti content in the Al—Si—Ti composite oxide, for example, it may be 320 nm or more, or 325 nm or more. ..

In the present invention, the absorption edge wavelength of the absorption peak measured by ultraviolet spectrophotometry is a wavelength indicating the absorption edge of the diffused reflection spectrum measured by an ultraviolet-visible spectrophotometer (or an ultraviolet spectrophotometer). Specifically, it is the maximum wavelength at which the value of the spectral intensity is 0.3 or more when the absorption intensity is KM-converted using the Kubelker-Munk function (KM function).

<< Requirements (3) >>
The Al—Si—Ti composite oxide of the present invention satisfies the following formula.
ΔLAS = LAS ₁₅₀ -LAS ₂₅₀ ≧ 190 μmol / g
In the formula, LAS ₁₅₀ and LAS ₂₅₀ are the amounts of Lewis acid points per unit mass of the composite oxide measured by infrared spectroscopy using pyridine as a probe molecule, and are pyridines when preparing a measurement sample. It is the amount of Lewis acid points when the exhaust temperature after adsorption is 150 ° C. and 250 ° C., respectively.

LAS ₁₅₀ , LAS ₂₅₀ and ΔLAS are more specifically measured by the following method or an equivalent method.
The measurement atmosphere is evacuated at 500 ° C. for 1 hour and then cooled to 30 ° C. Then, the temperature is raised to 150 ° C. again, and the background spectrum is measured. Next, pyridine vapor is introduced into the measurement atmosphere, exhaust treatment is performed, and an IR spectrum (hereinafter referred to as "150 ° C. exhaust spectrum") is measured. Further, the measurement atmosphere is heated to 250 ° C. under vacuum exhaust, cooled to 150 ° C., and the IR spectrum (hereinafter referred to as “250 ° C. exhaust spectrum”) is measured.

The difference spectrum between the 150 ° C. exhaust spectrum and the background spectrum is obtained, and the amount of Lewis acid points is determined from the area of the absorption band near 1450 cm- ¹ , the absorption constant (1.67 cm / mol), and the sample mass. The measurement is performed three times, and the average value of the amount of Lewis acid points in the three measurements is adopted as LAS ₁₅₀ . Further, the amount of Lewis acid points is obtained in the same manner as LAS ₁₅₀ based on the difference spectrum between the 250 ° C. exhaust spectrum and the background spectrum, and the average value of three measurements is adopted as LAS ₂₅₀ . Further, the value of ΔLAS (= LAS ₁₅₀ -LAS ₂₅₀ ) is calculated from these values.

Incidentally, BAS _0.99 is the amount of Bronsted acid sites in the case of the exhaust gas temperature after pyridine adsorption and 0.99 ° C., the absorption band (absorption constant near 1540 cm ^-1 in place of the absorption band near 1450 cm ^-1: 2. The measurement can be performed in the same manner as the measurement method of LAS ₁₅₀ except that the focus is on 22 cm / mol).

The difference (ΔLAS) between the amount of Lewis acid points in the 150 ° C. exhaust gas (LAS ₁₅₀ ) and the amount of Lewis acid points in the 250 ° C. exhaust gas (LAS ₂₅₀ ) is 190 μmol / g or more, preferably 200 μmol / g or more. The upper limit is preferably 220 μmol / g, more preferably 215 μmol / g, and even more preferably 210 μmol / g from the viewpoint of ease of manufacture and the like. When ΔLAS is 190 μmol / g or more, it means that components other than alumina (silica component, titania component) are uniformly dispersed.

The value of ΔLAS can be increased by a method such as reducing the proportion of the basic aluminum salt or adding water vapor to the firing atmosphere in the production method described later, for example.
In the Al—Si—Ti composite oxide of the present invention, the dispersibility of the titania component is good, and the components other than alumina are uniformly dispersed, so that the photoactivity is suppressed, and therefore the cosmetic and resin fillers. , Additives to surface coating materials (for the purpose of optical scattering, refractive index adjustment, etc.) and the like can be preferably applied.

<< Optional requirements, etc. >>
The Al—Si—Ti composite oxide of the present invention may contain other elements in addition to aluminum, silicon and titanium. Examples of other elements include phosphorus (P), boron (B), zirconium (Zr) and the like. When the Al—Si—Ti composite oxide contains other elements, the content of these in the Al—Si—Ti composite oxide is, for example, 1.0% by mass or more in terms of oxide of each element. It may be 20% by mass or less. Further, although it depends on the production method, a small amount of alkali metal elements (sodium (Na), potassium (K), etc.) in the production process may remain in the Al—Si—Ti composite oxide.
A part of the structure of the Al—Si—Ti composite oxide of the present invention is schematically shown by a chemical formula as follows.

An example of the structure of an Al-Si-Ti composite oxide

本発明のＡｌ−Ｓｉ−Ｔｉ複合酸化物には、通常、Ｘ線回折分析により、アナターゼ型チタニア（１０１）面の結晶構造を示す回折ピーク及びルチル型（１１０）面の結晶構造を示す回折ピーク（以下、「チタニア回折ピーク」ともいう。）が検出されない。チタニア回折ピークが検出されないということは、本発明のＡｌ−Ｓｉ−Ｔｉ複合酸化物にはチタニア成分の凝集が実質的に存在しないということを意味する。

The Al—Si—Ti composite oxide of the present invention usually has a diffraction peak showing a crystal structure of an anatase type titania (101) plane and a diffraction peak showing a crystal structure of a rutile type (110) plane by X-ray diffraction analysis. (Hereinafter, also referred to as "titania diffraction peak") is not detected. The fact that the titania diffraction peak is not detected means that the Al—Si—Ti composite oxide of the present invention has substantially no aggregation of the titania component.

<Measurement conditions for X-ray diffraction analysis>
Approximately 30 ml of the measurement sample is collected in a magnetic crucible (B-2 type), heated at 110 ° C. for 12 hours for heat treatment, and then placed in a desiccator to cool to room temperature. Next, after crushing the cooled product in a mortar for 15 minutes, the crystal morphology of the measurement sample is measured using an X-ray diffractometer (eg, RINT1400 manufactured by Rigaku Denki Co., Ltd.).

Examples of the shape (form) of the Al—Si—Ti composite oxide of the present invention include particles (powder), sol, and gel. Particles are preferable from the viewpoint of application to cosmetics, resin fillers, additives to surface coating materials, and the like.

When the Al—Si—Ti composite oxide of the present invention is a particle, the specific surface area (SA) measured by the BET method may be, for example, 280 m ² / g or more, preferably 290 m ² / g. That is all. The specific surface area (SA) may be, for example, 450 m ² / g or less, preferably 430 m ² / g or less. When the specific surface area (SA) is 450 m ² / g or less, the decrease in mechanical strength of the Al—Si—Ti composite oxide can be suppressed more effectively.

The value of ΔLAS per unit specific surface area of the Al—Si—Ti composite oxide of the present invention, that is, the value obtained by dividing the ΔLAS by the specific surface area is preferably 0.50 to 0.70 μmol / m ² , more preferably. Is 0.55 to 0.65 μmol / m ² . Within this range, the Al—Si—Ti composite oxide of the present invention can exhibit photoactivity when used as an optical material or when applied to cosmetics, resin fillers, additives for surface coating materials, and the like. Low sex.

The value of BAS ₁₅₀ of the Al—Si—Ti composite oxide of the present invention is preferably 0 μmol / g. That is, in the difference spectrum between the 150 ° C. exhaust spectrum and the background spectrum described above, preferably, no absorption band around 1540 cm- ¹ attributed to the Bronsted acid point is observed.

In the Al—Si—Ti composite oxide of the present invention, the pore volume (PV) measured by the water pore filling method may be, for example, 0.45 ml / g or more, preferably 0.50 ml / g or more. Is. The pore volume (PV) may be, for example, 0.80 ml / g or less, preferably 0.70 ml / g or less. When the pore volume (PV) is 0.80 ml / g or less, the decrease in strength can be suppressed more effectively.

[Method for producing Al-Si-Ti composite oxide]
The method for producing an Al—Si—Ti composite oxide according to the present invention is
A first aqueous solution containing mineral acid and a titanium mineral acid compound containing the basic component of the mineral acid and a second aqueous solution containing a basic aluminum salt are mixed in the presence of silicate ions to pH 6 The first step of obtaining a mixed solution of .5-9.5 and precipitating the precursor of the Al—Si—Ti composite oxide, and the precursor is separated from the mixed solution and then heat-treated to obtain the Al. It is characterized by including a second step of obtaining a −Si—Ti composite oxide.
The Al—Si—Ti composite oxide according to the present invention described above can be produced by the method for producing an Al—Si—Ti composite oxide according to the present invention.

(First step)
The first aqueous solution used in the first step is usually an acidic aqueous solution, and the second aqueous solution is usually a basic aqueous solution.
Examples of mineral acids contained in the first aqueous solution include hydrogen chloride, sulfuric acid and nitric acid. In the present invention, the "basic component of mineral acid" is a component obtained by removing hydrogen ions from mineral acid, and for example, the basic components of hydrogen chloride, sulfuric acid and nitric acid are chloride ion, sulfate ion and nitrate ion, respectively. is there.

Examples of titanium mineral salts contained in the first aqueous solution include titanium mineral salts such as titanium tetrachloride, titanium trichloride, titanium sulfate and titanium nitrate, titanium oxychloride and titanium oxysulfate (titanyl sulfate). Be done. In particular, titanyl sulfate is preferably used.

The "titanium mineral acid compound containing a basic component of a mineral acid" is, for example, a titanium mineral acid compound containing a sulfate ion when the mineral acid is sulfuric acid, that is, titanium sulfate, titanium oxysulfate (titanyl sulfate). And so on.

From the viewpoint of satisfactorily dispersing the titania component in the composite oxide without agglomeration, the value of (amount of substance of titanium mineral acid compounds (converted to the amount of substance of titanium) / (amount of substance of mineral acid) is usually set. If it is 0.15 to 0.70, there is no particular limitation, but it is preferable that the precursor of the composite oxide is 0.25 to 0.65 due to the post-treatment.

The first aqueous solution is preferably free of acidic aluminum salts. When the first aqueous solution does not contain an acidic aluminum salt, the aggregation of the titania precursor can be more effectively suppressed when the precursor of the composite oxide is produced.

The first aqueous solution is prepared, for example, by adding an aqueous solution of mineral acid to an aqueous solution of a titanium mineral acid salt compound. An aqueous solution of a titanium mineral acid salt compound is prepared, for example, by dissolving the titanium mineral acid salt compound or a hydrate thereof in water.
Examples of the basic aluminum salt contained in the second aqueous solution include sodium aluminate, potassium aluminate and the like.

In the first step, the first aqueous solution and / or the second aqueous solution contains silicate ions, but the timing of adding silicate ions to the first aqueous solution and / or the second aqueous solution (more accurately, The timing of adding an aqueous solution containing silicate ions or a silicate compound capable of generating silicate ions in water is not particularly limited. The same shall apply hereinafter). For example, a first aqueous solution may be prepared by adding and mixing a titanium mineral acid compound, a mineral acid and a silicate ion to water substantially at the same time, or an aqueous solution containing a titanium mineral acid compound and a mineral acid may be prepared. It may be prepared and immediately before mixing with the second aqueous solution, silicate ions may be added and mixed to obtain the first aqueous solution. Similarly, a basic aluminum salt and a silicate ion may be added and mixed with water substantially at the same time to prepare a second aqueous solution, or an aqueous solution containing a basic aluminum salt may be prepared and first. A silicate ion may be added and mixed immediately before mixing with the aqueous solution of the above to obtain a second aqueous solution.

Content of titanium mineral acid salts and mineral acids contained in the first aqueous solution, basic aluminum salts contained in the second aqueous solution, and silicate ions contained in the first aqueous solution and / or the second aqueous solution. Is not particularly limited, and the Al content of the Al—Si—Ti composite oxide obtained in the second step described later is 60% by mass or more in terms of Al ₂ O ₃ , and the Si content is 1 in terms of SiO _2. It may be appropriately adjusted so that the content of Ti is 0 to 10% by mass and the content of Ti is ₁₂ to 30% by mass in terms of TiO ₂ .

When the first aqueous solution contains silicate ions, for example, an acidic or neutral silicate compound may be used as the silicate compound to be used. Examples of the acidic silicic acid compound include silicic acid, and the concentration of silicic acid ion (converted to SiO ₂ concentration) in the first aqueous solution is preferably 5.0% by mass or less.

When the second aqueous solution contains silicic acid ions, for example, a basic or neutral silicic acid compound may be used as the silicic acid compound. Examples of the basic silicic acid compound include sodium silicate, and the concentration of silicate ions (converted to SiO ₂ concentration) in the second aqueous solution is preferably 5.0% by mass or less.

The conditions for preparing the first aqueous solution are not particularly limited, but the temperature at the time of preparation is set to 60 ° C. or lower from the viewpoint of ensuring a state in which the titanium mineral acid compounds are not crystallized in the first aqueous solution. Is preferable. The temperature at which the first aqueous solution is prepared is, for example, room temperature (23 ° C.) or higher, preferably 30 ° C. or higher, from the viewpoint of facilitating the dissolution of the titanium mineral acid salts compound.

In the first step, the first aqueous solution and the second aqueous solution are mixed to obtain a mixed solution having a pH of 6.5 to 9.5. By setting the pH of the mixed solution within the above numerical range, the precursor of the Al—Si—Ti composite oxide can be stably precipitated in the mixed solution. The pH of the mixed solution is preferably 6.5-8.5, more preferably 6.5-7.5. By setting the pH in the above range, it becomes easy to remove impurities from the precursor of the Al—Si—Ti composite oxide.

As a method of mixing the first aqueous solution and the second aqueous solution, a method of adding the first aqueous solution to the second aqueous solution and mixing them can be used. Further, the first aqueous solution may be continuously added to the second aqueous solution. In the case of continuous addition, the time from the start of addition to the completion of addition may be 3 minutes or more on the lower limit side, preferably 5 minutes or more, and 20 minutes or less on the upper limit side, which is preferable. Is within 15 minutes. In particular, when the first aqueous solution is added to the second aqueous solution and mixed, the formation of crystals such as bayarite and gibbsite in addition to pseudoboehmite is sufficiently suppressed, and the aggregation of titania is suppressed. From the viewpoint of more effectively securing the specific surface area of the obtained Al—Si—Ti composite oxide, it is preferably 15 minutes or less.

Other conditions for mixing the first aqueous solution and the second aqueous solution are not particularly limited. For example, when the first aqueous solution is added to the second aqueous solution and mixed, the second aqueous solution is placed in a container with a stirrer and usually heated to 40 to 80 ° C., preferably 55 to 70 ° C. and held. , The temperature of the second aqueous solution is ± 10 ° C., preferably ± 2 ° C., more preferably ± 1 ° C. by adding the first aqueous solution to mix the first aqueous solution and the second aqueous solution. You can.

(Second step)
The second step is a step of separating the precursor of the Al—Si—Ti composite oxide obtained in the first step from the mixed solution and then heat-treating to obtain the Al—Si—Ti composite oxide. ..
The precursor of the Al—Si—Ti composite oxide (hereinafter, also simply referred to as “precursor”) may be washed before being subjected to heat treatment, and for example, the by-product salt may be removed by washing. The conditions for washing the precursor are not particularly limited. Examples of the cleaning liquid for cleaning the precursor include an aqueous ammonia solution and the like.

In addition, the precursor may be aged before being subjected to heat treatment. Examples of the aging method include a method in which the precursor is aged in a mixed solution at 80 to 120 ° C. for 5 to 20 hours using an aging tank equipped with a reflux machine.

The precursor may be separated from the mixed solution by filtration or the like, washed optionally, and then dried at, for example, 70 to 150 ° C., preferably 90 to 130 ° C., and then subjected to firing. The precursor may be molded into a desired shape by kneading, extrusion molding or the like before drying, or may be pulverized after firing.

The conditions for firing the precursor are not particularly limited, but for example, the firing temperature may be 400 to 700 ° C., 450 to 650 ° C., or 500 to 600 ° C. The firing time may be, for example, 0.5 to 10 hours, or 2 to 8 hours.

Examples of the firing atmosphere include an inert gas atmosphere and an atmospheric atmosphere. Moreover, the firing atmosphere may contain water vapor.
Although the Al—Si—Ti composite oxide according to the present invention and the method for producing the same have been described above, the present invention is not limited to the above embodiment.

Hereinafter, the contents of the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
[Measuring method]
Various measurements were performed as follows.

<Absorption edge wavelength in UV spectroscopic analysis>
Using an ultraviolet-visible spectrophotometer (V-660 manufactured by JASCO Corporation), an integrating sphere unit ISV-772 for diffuse reflection measurement was attached, and the ultraviolet visible light diffuse reflection spectrum was measured as follows. ..

After 200 mg of the measurement sample was filled in the cell holder for the diffuse reflection sample, the absorbance was measured at room temperature. Specifically, in the photometric mode, the bandwidth is 5.0 nm, the measurement range is 500-200 nm, the data acquisition interval is 0.1 nm, the scanning speed is 100 nm / min, the light source switching wavelength is 340 nm, and the wave number range is 500-200 nm. Background corrected. The background measurement was performed under the above conditions by using a reference white plate.

The method of calculating the absorption edge from the diffuse reflection spectrum obtained above is the maximum that the value of the spectral intensity becomes 0.3 or more by performing the KM conversion using the Kubelker-Munk function (KM function). The wavelength was calculated as the absorption edge wavelength.

<Amount of Lewis acid, ΔLAS, etc.>
33 mg of the measurement sample was filled in a disk having an inner diameter of 20 mm and installed in a measuring device (FT-IR4600 manufactured by JASCO Corporation).
The measurement atmosphere was evacuated at 500 ° C. for 1 hour and then cooled to 30 ° C. Then, the temperature was raised to 150 ° C. again, and the background spectrum was measured. Next, pyridine vapor was introduced into the measurement atmosphere, exhaust treatment was performed, and an IR spectrum (hereinafter referred to as "150 ° C. exhaust spectrum") was measured. Further, the measurement atmosphere was heated to 250 ° C. under vacuum exhaust, cooled to 150 ° C., and the IR spectrum (hereinafter referred to as “250 ° C. exhaust spectrum”) was measured.

Obtain the difference spectrum between the 150 ° C. exhaust spectrum and the background spectrum, and determine the amount of Lewis acid points from the area of the absorption band near 1450 cm- ¹ , the absorption constant (1.67 cm / mol), and the sample mass (33 mg). I asked. The measurement was performed three times, and the average value of the amount of Lewis acid points in the three measurements was adopted as LAS ₁₅₀ . Further, the amount of Lewis acid points was obtained in the same manner as LAS ₁₅₀ based on the difference spectrum between the 250 ° C. exhaust spectrum and the background spectrum, and the average value of three measurements was adopted as LAS ₂₅₀ . Further, the value of ΔLAS (= LAS ₁₅₀ -LAS ₂₅₀ ) was calculated from these values.

Further, in the difference spectrum between the 150 ° C. exhaust spectrum and the background spectrum described above, the presence or absence of an absorption band around 1540 cm ^-1 attributed to the Bronsted acid point was confirmed.

<X-ray diffraction analysis>
About 30 ml of the measurement sample was collected in a magnetic crucible (B-2 type), heated at 110 ° C. for 12 hours for heat treatment, and then placed in a desiccator and cooled to room temperature. Next, the cooled product was pulverized in a mortar for 15 minutes, and then the crystal morphology was measured using an X-ray diffractometer (RINT1400, manufactured by Rigaku Denki Co., Ltd.).

<Specific surface area>
About 30 mL of the measurement sample was collected in a magnetic crucible (B-2 type), heat-treated at a temperature of 300 ° C. for 2 hours, and then placed in a desiccator to cool to room temperature. Next, 1 g of this cooled sample was taken, and the specific surface area (m ² / g) of the sample was measured by the BET method using a fully automatic surface area measuring device (manufactured by Yuasa Ionics, Multisorb 12 type).

<Measurement method of average pore diameter and pore volume>
The measurement was performed by a mercury intrusion method (mercury contact angle: 150 degrees, surface tension: 480 dyn / cm). The pore volume was defined as the volume of pores having a pore diameter of 40 Å or more, and the average pore volume was defined as the pore diameter corresponding to 50% of the pore volume.

[Example 1]
<Preparation of precursor a of Al-Si-Ti composite oxide>
In a tank with a steam jacket with a capacity of 100 L, 10.5 kg of a 22 mass% sodium aluminate aqueous solution (manufactured by Nikki Catalyst Kasei Co., Ltd.) in terms of Al ₂ O ₃ is placed, diluted with 51 kg of ion-exchanged water, and then SiO _{2 is used.} In terms of conversion, add 1.80 kg of a 5 mass% sodium silicate aqueous solution (manufactured by AGC SI Tech Co., Ltd .; a product having a SiO ₂ concentration of 24 mass% diluted with ion-exchanged water) with stirring, and add to 60 ° C. It was warmed to prepare a second aqueous solution containing a basic aluminum salt.

Solution A was prepared by dissolving 1.82 kg of titanyl sulfate (manufactured by Teika Co., Ltd.) containing 33% by mass of titanium in terms of TiO ₂ in 10 kg of ion-exchanged water, and a 25% by mass aqueous sulfuric acid solution (solution B) was added. It was mixed with 62 kg and heated to 50 ° C. to prepare a first aqueous solution containing a titanium mineral salt compound (titanyl sulfate) and sulfuric acid. The value of (Amount of substance of titanium mineral acid compounds (converted to the amount of substance of titanium)) / (Amount of substance of mineral acid), that is, the value of (Amount of substance of titanyl sulfate) / (Amount of substance of sulfuric acid) is 0. It was 39.

Subsequently, the first aqueous solution was added to the tank containing the second aqueous solution at a constant rate for 10 minutes using a roller pump until the pH reached 7.2, and the precursor of the composite oxide (hydration) was added. A mixed solution 1 (slurry) in which product) a was precipitated was obtained. The time from mixing the solution A and the solution B until the addition of the first aqueous solution to the second aqueous solution was completed (addition completion time) was 30 minutes.

<Preparation of Al—Si—Ti composite oxide particles 1>
The obtained mixed solution 1 (slurry in which the precursor a was precipitated) was stirred at 60 ° C. for 1 hour, dehydrated using a flat plate filter, and further washed with 150 L of a 0.3 mass% ammonia aqueous solution. The precursor a in the cake state after washing was diluted with ion-exchanged water so as to have 10% by mass in terms of Al ₂ O ₃ , and then the pH was adjusted to 10.5 with 15% by mass of ammonia water. The obtained diluted solution was transferred to an aging tank equipped with a reflux machine and aged at an aging temperature of 95 ° C. for 10 hours with stirring. The mixed solution after completion of aging was dehydrated and concentrated and kneaded to a predetermined water content while kneading with a double-armed kneader equipped with a steam jacket. The obtained kneaded product was molded into a cylindrical shape having a diameter of 1.6 mm by an extrusion molding machine and dried at 110 ° C. The dried molded product was fired in an electric furnace in an air atmosphere at a temperature of 550 ° C. for 3 hours, and the obtained fired product was pulverized to obtain Al—Si—Ti composite oxide particles 1 containing Si, Ti and Al. Obtained.

Table 2 shows the properties of the Al—Si—Ti composite oxide particles 1 (Al content, Si content, Ti content, pore volume (PV), specific surface area (SA), ΔLAS, etc.).
Further, the ultraviolet-visible light diffuse reflection spectrum of the composite oxide particles 1 is shown in FIG. When the absorption edge wavelength of the Al—Si—Ti composite oxide particle 1 was calculated from the analysis result, it was 339 nm.

Further, the result of the X-ray diffraction analysis of the composite oxide particles 1 is shown in FIG. From the composite oxide particles 1, it is attributed to the peak assigned to the anatase-type titania (101) plane shown at 2θ = 25.5 ° and the rutile-type titania (110) plane shown at 2θ = 27.5 °. No peak was detected.

[Examples 2 to 5, Comparative Examples 1 to 4]
Al—Si—Ti composite oxide particles 2 to 5 and R1 to R4 were produced by the same method as in Example 1 except that the blending amount of each component was changed as shown in Table 1. The evaluation results are shown in Table 2.

[Comparative Example 5]
In a tank with a steam jacket having a capacity of 100 L, 7.00 kg of a 22 mass% sodium aluminate aqueous solution in terms of Al ₂ O ₃ is placed, diluted with 16.5 kg of ion-exchanged water, and then 5 mass% in SiO ₂ equivalent. 1.80 kg of sodium silicate solution was added with stirring and heated to 60 ° C. to prepare a second aqueous solution containing a basic aluminum salt.

A solution prepared by dissolving 1.82 kg of titanyl sulfate in an amount of 33% by mass in terms of TiO ₂ in 10 kg of ion-exchanged water was heated to 50 ° C., and 1.55 kg of a 48% by mass sodium hydroxide solution was added to this solution at 8.5 kg. A solution diluted with ion-exchanged water was added at a constant rate over 90 minutes until the pH reached 7.2 to prepare a titania precursor (gel).

A solution obtained by diluting 11.0 kg of a 7 mass% aluminum sulfate aqueous solution in terms of Al ₂ O ₃ with 19 kg of ion-exchanged water was added to the second aqueous solution at a constant rate until the pH reached 7.2 using a roller pump. The mixture was added over a minute to obtain a mixed solution (slurry) in which the alumina precursor was precipitated. 27 kg of the titania precursor was further mixed with this mixed solution to obtain a mixed solution R5.

Composite oxide particles R5 were obtained in the same manner as in <Preparation of Al—Si—Ti composite oxide particles 1> of Example 1 except that the mixed solution 1 was changed to the mixed solution R5. The evaluation results are shown in Table 2. The results of the ultraviolet-visible light diffuse reflection spectrum and the X-ray diffraction analysis are also shown in FIGS. 1 and 2, respectively.

[Comparative Example 6]
In a tank with a steam jacket having a capacity of 100 L, 8.16 kg of a 22 mass% sodium aluminate aqueous solution in terms of Al ₂ O ₃ is placed, diluted with 41 kg of ion-exchanged water, and then a 5 mass% sodium silicate solution in terms of SiO 2 is added. 1.80 kg was added with stirring and heated to 60 ° C. to prepare a second aqueous solution containing a basic aluminum salt. A solution obtained by diluting 7.43 kg of 7% by mass aluminum sulfate aqueous solution (manufactured by Nikki Catalyst Kasei Co., Ltd.) with 13 kg of ion-exchanged water in terms of Al ₂ O _{3 and} 1.82 kg of titanyl sulfate in terms of TiO _2. Was mixed with a solution of 10 kg of ion-exchanged water and heated to 50 ° C. to prepare a first aqueous solution containing a titanium mineral salt and an acidic aluminum salt. Subsequently, the first aqueous solution was added to the tank containing the second aqueous solution at a constant rate for 10 minutes using a roller pump until the pH reached 7.2, and the precursor of the composite oxide (hydration) was added. A mixed solution R6 (slurry) in which the substance) was precipitated was obtained.
Composite oxide particles R6 were obtained in the same manner as in <Preparation of Al—Si—Ti composite oxide particles 1> of Example 1 except that the mixed solution 1 was changed to the mixed solution R6.

Since the Al—Si—Ti composite oxide according to the present invention has low photoactivity despite containing a titania component, it can be used as an optical material or added to cosmetics, resin fillers, and surface coating materials (optical scattering, It can be applied to those for the purpose of adjusting the refractive index, etc.).

Claims (7)

A composite oxide of aluminum, silicon and titanium that meets the following requirements (1) to (3).
Requirement (1): Aluminum content is 60% by mass or more in terms of Al ₂ O ₃ , silicon content is 1.0 to 10% by mass in terms of SiO ₂ , and titanium content is TiO ₂ It is 12 to 30% by mass in terms of conversion.
Requirement (2): The absorption edge wavelength of the absorption peak measured by ultraviolet-visible spectroscopy is 350 nm or less.
Requirement (3): Satisfy the following formula.
ΔLAS = LAS ₁₅₀ -LAS ₂₅₀ ≧ 190 μmol / g
[In the formula, LAS ₁₅₀ and LAS ₂₅₀ are the amounts of Lewis acid points per unit mass of the composite oxide measured by infrared spectroscopy using pyridine as a probe molecule, and are used in the preparation of measurement samples. It is the amount of Lewis acid points when the exhaust temperature after pyridine adsorption is 150 ° C. and 250 ° C., respectively. ] The composite oxide according to claim 1, wherein a diffraction peak showing a crystal structure of anatase-type titania (101) plane and rutile-type titania (110) plane is not detected by X-ray diffraction analysis. The composite oxide according to claim 1 or 2, wherein the specific surface area is 280 m ² / g or more and the pore volume is 0.45 ml / g or more. The composite oxide according to any one of claims 1 to 3, wherein the value of ΔLAS per unit specific surface area is 0.50 to 0.70 μmol / m ² . A method for producing a composite oxide of aluminum, silicon and titanium.
A first aqueous solution containing a mineral acid and a titanium mineral salt compound containing the basic component of the mineral acid and a second aqueous solution containing a basic aluminum salt are mixed in the presence of silicate ions to pH 6 The first step of obtaining a mixed solution of .5-9.5 and precipitating a precursor of the composite oxide, and the first step of separating the precursor from the mixed solution and then heat-treating to obtain the composite oxide. A method for producing a composite oxide, which comprises two steps. In claim 5, the value of (amount of substance of titanium mineral acid compounds (converted to the amount of substance of titanium)) / (amount of substance of mineral acid) in the first aqueous solution is 0.15 to 0.70. The method for producing a composite oxide according to the above. The method for producing a composite oxide according to claim 5 or 6, wherein the first aqueous solution is prepared at 60 ° C. or lower.

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