JPH0463807B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to spherical inorganic oxide particles whose main constituents are silica and an oxide of a group metal of the periodic table, and whose particle diameters are very uniform. (Prior Art and Problems to be Solved by the Invention) Conventionally, spherical particles with very uniform particle diameters have been used as standard particles for electron microscopic observation and powder particle size measurement. Polystyrene has the advantages of having a well-uniformed particle size, a true spherical shape, and the ability to synthesize particles of any particle size, and is used as the standard particle mentioned above. . However, it is said that when polymer particles such as polystyrene are used as standard particles for atomic microscopic observation, the polymer particle diameter becomes small due to the influence of the electron beam, making accurate observation impossible. Therefore, it is conceivable to use inorganic compound particles that are not easily affected by electron beams as standard particles. As inorganic compound particles, 1.0 μ with a well-uniformed particle size is recommended.
It is known that silica particles up to
Publication No. 41810). It is also produced by spray pyrolysis of metal alkoxide, and the particle size is 1.5~
Silica particles in the 20 μm range are also known, but these silica particles have a wide particle distribution and are therefore not suitable for use as standard particles as described above. As described above, inorganic compound particles with well-uniform particle diameters in the range of 1.5 to 20 μm have not yet been obtained. (Means for Solving the Problems) Therefore, the present inventors developed a spherical inorganic compound with well-uniformed particle diameters of 1.5 μm or more, which is suitably used as standard particles for electron microscopy and powder particle size measurement. We have been conducting research with the aim of synthesizing particles. As a result, they succeeded in synthesizing the desired inorganic oxide particles by using silica and an oxide of a metal from group 3 of the periodic table as the main constituents, and completed the present invention. That is, the present invention has silica and an oxide of a metal of group 3 of the periodic table as main components, and has a particle size of 1.5.
~20μm, and the standard deviation value of particle size is 1.00
It is a spherical inorganic oxide particle that ranges from ~1.10. Note that the standard deviation value as used herein is an index indicating the degree of variation in particle diameter of inorganic oxide particles, as defined later. The inorganic oxide particles of the present invention are an oxide of a silicon atom of silica and a metal of group of the periodic table, for example,
Lithium oxide, sodium oxide, potassium oxide, etc. are bonded through oxygen, and the main constituents are oxides of metals from Group 3 of the periodic table and silica. In the inorganic oxide particles of the present invention, silica and an oxide of a group metal of the periodic table are chemically bonded, and these constituent components cannot be physically separated. Moreover, the chemical bonding of both components can be confirmed by measuring the infrared spectrum of the inorganic oxide particles. The oxide of a metal belonging to group 1 of the periodic table is necessary in order to make the particle size of the inorganic oxide particles of the present invention a relatively large value of 1.5 to 20 μm. The composition ratio of the oxides of metals in Group 1 of the periodic table in the inorganic oxide particles is selected from a wide range, but in order to improve the standard deviation value of the particle size of the obtained inorganic oxide particles and the shape 0.1 to 20 to keep it spherical.
mol %, preferably in the range of 2 to 13 mol %. The inorganic oxide particles of the present invention may contain, in addition to the above-mentioned oxides of metals from group 3 of the periodic table, other substances as long as they do not adversely affect the variation in particle size or shape of the inorganic oxide particles. A metal oxide may be included. Examples of oxides of other metals include oxides of metals in Group Group of the Periodic Table, such as magnesium oxide, calcium oxide, strontium oxide, and barium oxide; oxides of metals in Group Group of the Periodic Table, such as aluminum oxide; titanium oxide, zirconium oxide,
Examples include oxides of metals in group 3 of the periodic table, such as hafnium oxide. In order to reduce the variation in the particle size of the inorganic oxide particles and to maintain the spherical shape of these metal oxides,
It is suitable that the composition ratio in the inorganic oxide particles is 20 mol% or less, preferably 10 mol% or less. The shape, particle size, particle size distribution, etc. of the inorganic oxide particles of the present invention can be measured by observation using a scanning electron microscope. The inorganic oxide particles of the present invention have a particle size of 1.5 μm to 20 μm, preferably,
The particle size is in the range of 2.0 μm to 15 μm, and the particle size distribution is very narrow, and the standard deviation value of the particle size is in the range of 1.00 to 1.10, preferably in the range of 1.00 to 1.05, and more preferably in the range of 1.00 to 1.03. You can also do it. When the particle size is less than 1.5 μm, the variation in particle size is large, and the standard deviation value is 1.00 to 1.10 specified by the present invention.
may not fall within the range. In addition, the particle size
Inorganic oxide particles exceeding 20 μm are not practical because it takes too much time to produce them. The inorganic oxide particles of the present invention, which are mainly composed of silica and an oxide of a metal from group 3 of the periodic table, are compared to general inorganic compound particles even though they do not undergo a sintering process. Small surface area, typically 0.01
The specific surface area is in the range ˜50 m ² /g, usually in the range 0.01 to 5 m ² /g. The inorganic oxide particles of the present invention are mostly amorphous or a mixture of amorphous and partially crystalline particles. This determination can be confirmed by X-ray diffraction analysis of the inorganic oxide particles of the present invention. Further, the inorganic oxide particles of the present invention have -OH groups bonded to their surfaces. The amount of OH groups can be confirmed by measurement using an alkali neutralization method.
The inorganic oxide particles of the present invention generally have OH groups in the range of 0.00001 to 0.5 mmol/g, depending on the specific surface area. Furthermore, the specific gravity of the inorganic oxide particles of the present invention is
Although it is not possible to give a general indication because it varies depending on the composition ratio of silica and metal oxide of group 3 of the periodic table, the most common specific gravity is in the range of 1.90 to 2.20. Since the inorganic oxide particles of the present invention have the various properties described above, they can be used for various purposes, but the production method is not particularly limited as long as the method provides the above properties. Regarding the most typical methods,
This will be explained in detail below. That is, this is a method in which a hydrolyzable organosilicon compound is hydrolyzed in a reaction solution in the presence of an alkali metal ion from group 3 of the periodic table. In this method, it is sufficient that an alkali metal ion of Group 1 of the periodic table is generally present in a reaction solution consisting of water, ammonia, and a solvent, and other conditions are not particularly limited. The hydrolyzable organosilicon compound that is the raw material is not particularly limited, but typically includes alkoxysilanes represented by the general formula Si(OR) ₄ or SiR′ _o (OR) _4-o ,
Alternatively, low condensates obtained by partially hydrolyzing alkoxysilanes are easily available industrially, and one or a mixture of two or more thereof is preferably used. In addition, in the above general formula, R and
R′ is an alkyl group, such as methyl group, ethyl group,
Lower alkyl groups such as isopropyl group and butyl group are preferred. n is an integer from 1 to 3. In addition to the above-mentioned hydrolyzable organosilicon compound, a 20%
If it is less than mol%, preferably less than 10 mol%,
Other hydrolyzable organometallic compounds can also be used in conjunction. As other organometallic compounds, known compounds may be employed without any restrictions. For example, the general formula M ¹ (OR′), M ² (OR′) ₂ , M ³ (OR′) ₃ ,
M ⁴ (OR') ₄ (where R' is an alkyl group) metal alkoxide compound or one or two alkoxide groups (OR') in the above general formula are substituted with a carboxyl group or β-dicarbonyl group Compounds that have been used are preferred. where M ¹ is a group metal, M ²
is a group metal, ^M3 is a group metal, and ^M4 is a group metal, such as lithium, sodium, potassium, magnesium, calcium, strontium, barium, aluminum, titanium, zirconium, germanium, Hafnium, tin or lead are preferably used. Specific examples of the above-mentioned compounds that are generally preferably used in the present invention include NaOCH ₃ , NaOC ₂ H ₅ , NaOC ₃ H ₇
In place of organic sodium compounds such as and the above Na,
Group compounds substituted with Li, K, etc., Mg
( _{OCH3 ) 2} , Mg( _OC2H5 ) ₂ , Mg( _OC3H7 ) ₂ , _Mg
Organomagnesium compounds such as (OC ₄ H ₉ ) ₂ , Mg(OC ₅ H ₁₁ ) _{2 ,} group compounds in which Ca, Sr, Ba, etc. are substituted for the above Mg, Al(OC ₂ H ₅ ) ₂ , Al
Compounds such as (OC ₃ H ₇ ) ₂ , Al(OC ₄ H ₉ ) ₂ and the above Al
In place of B, group compound, Ti
(O-isoC ₃ H ₇ ) ₄ , Ti(O-nC ₄ H ₉ ) ₄ , Ti(O-
CH ₂ CH (C ₂ H ₅ ) C ₄ H ₉ ) ₄ , Ti (OC ₁₇ H ₃₅ ) ₄ , Ti
(O-isoC ₃ H ₇ ) ₂ [CO(CH ₃ )CHCOCH ₃ ] ₂ , Ti(O
−nC ₄ H ₉ ) ₂ [OC ₂ H ₄ N(C ₂ H ₄ OH) ₂ ] ₂ , Ti(OH) ₂
[OCH (CH ₃ ) COOH] ₂ , Ti (OCH ₂ CH (C ₂ H ₅ )
CH(OH) _C3H7 ) ₄ , Ti ₍ O _{- nC4H9} ) ₂
(OCOC ₁₇ H ₃₅ ) and other compounds and instead of the above Ti,
Group metal compounds substituted with Zr, Ge, Hf, Sn, Pb, etc. Also, CaCl ₂ , Ca
[HOC ₆ H ₄ COO] Compounds such as _{2.2H 2} O can also be suitably used. In the following description, the above-mentioned organosilicon compound and other organometallic compounds used as necessary may be simply referred to as an organometallic compound. In the present invention, the above-mentioned hydrolyzable organometallic compound can be added to the reaction solution as it is without using a solvent, but in order to easily control the reaction, the concentration of the organosilicon compound or If other organometallic compounds are used, their total concentration is generally below 50% by weight, especially between 5 and 5%.
It is preferable to use it diluted to a range of 50% by weight. There are no particular restrictions on the use of this diluted solution, as long as it can dissolve hydrolyzable organometallic compounds and can be mixed uniformly with water at a certain ratio. Alcohols such as methanol, ethanol, isopropyl alcohol, butanol, ethylene glycol, and propylene glycol are preferably used. Next, a homogeneous mixed solution is prepared as a reaction solution, which generally consists of water, ammonia, and a solvent, and also contains an alkali metal ion of group 1 of the periodic table. The solvent used for the reaction solution is not particularly limited as long as it can prepare a homogeneous solution with water and ammonia, and the above-mentioned alcohols are generally preferred, and generally the more carbon atoms are used, the better the yield. There is a tendency for the particle size of the inorganic oxide particles to be increased. In addition, the concentrations of water and ammonia in the reaction solution are generally 0.5 to 0.
It may be determined by selecting from the range of 50 mol/, 1.0 to 10 mol/. Note that the concentrations of water and ammonia in the reaction solution are amounts expressed as water/solvent (total) and ammonia/solvent (total), respectively.Solvent (total) means the solvent of the initial reaction solution + organic metal. The total amount of the solvent of the solution of the compound + the solvent generated in the hydrolysis reaction of the organometallic compound + the solvent of the control mixture of ammonia and water described later is shown. Next, the reaction solution in which an alkali metal ion of group 1 of the periodic table is present is generally a compound capable of producing the alkali metal ion in the above-mentioned mixed solution of water, ammonia, and a solvent, and is added and mixed without particular limitation. The concentration is adjusted to a predetermined concentration. Compounds that can generate the above alkali metal ions include:
For example, alkali metal hydroxides of periodic group such as lithium hydroxide, sodium hydroxide, and potassium hydroxide are preferably used. The concentration of the above-mentioned alkali metal ions in the reaction solution cannot be determined unconditionally because it varies depending on conditions such as the particle size of the inorganic oxide particles to be produced, but it is generally determined based on the total weight of water, ammonia, and solvent used in the reaction solution. 0.001~1mol/, especially 0.002~
It is preferably in the range of 0.1 mol/. That is,
If the concentration of the alkali metal ions in the reaction solution is lower than the above range, the effect of the present invention will not be sufficiently exhibited, the particle size of the inorganic oxide particles will not increase, and the concentration of the alkali metal ions in the reaction solution will be lower. The higher the value, the more likely it is that inorganic oxide particles with a larger particle size will be obtained, but if the value is higher than the above range, inorganic oxide particles with various particle sizes will be produced, making it difficult to obtain inorganic oxide particles with a uniform particle size. do not have. Therefore,
In the present invention, the initial reaction solution may generally be prepared to maintain a predetermined alkali metal ion concentration during the continuation of the reaction, but if necessary, a compound capable of producing alkali metal ions may be added during the reaction. It is also possible to adjust the alkali metal ion concentration to a predetermined value. In the hydrolysis reaction, while the reaction is continued, water and ammonia in the reaction solution are kept substantially unchanged from the predetermined initial values generally selected in the ranges of 0.5 to 50 mol/ and 1 to 10 mol/, respectively. Control is an effective way to further improve particle size uniformity. As a method for maintaining the concentrations of water and ammonia in such a reaction solution uniform without substantially changing them, it is common to add a hydrolyzable raw material to a reaction solution of water, ammonia, and a solvent that has been adjusted to a predetermined concentration in advance. This can be easily achieved by sequentially and simultaneously adding an organic silicon compound, water, and ammonia at a rate that maintains a predetermined concentration. Note that the above-mentioned concentration of water and ammonia in the reaction solution is not substantially changed by maintaining them within ±50%, preferably within ±30% of the predetermined initial concentration (value). The reaction temperature varies depending on various conditions and cannot be absolutely limited, but it is generally 0 to 40°C under atmospheric pressure.
℃, preferably 5 to 30℃. The inorganic oxide particles of the present invention can be obtained by the above method, but if the above-mentioned hydrolysis reaction is continuously carried out for a long time, a small amount of new fine particles will be generated, and the inorganic oxide particles of uniform particle size will be generated. It becomes difficult to obtain oxide particles. Therefore, when producing inorganic oxide particles of the present invention that have a relatively large particle size, the hydrolysis reaction is stopped before fine new particles are generated, and the resulting inorganic oxide particles are subjected to the reaction. After separation from the liquid, a method is preferably adopted in which the seed particles are dispersed again in the reaction liquid and the above-mentioned hydrolysis reaction is performed to grow the seed particles. (Effects) The inorganic oxide particles of the present invention have a relatively large particle size of 1.5 to 20 μm. The particle size can be adjusted to any desired size within this range. Moreover, the particle diameters are extremely uniform, and the standard deviation value defined later can be an excellent value of 1.00 to 1.10, preferably 1.00 to 1.05, and further 1.00 to 1.03. 1.5~20μm like this
The present invention is the first to provide spherical inorganic oxide particles with relatively large particle diameters and well-uniform particle diameters. The inorganic oxide particles of the present invention having the above characteristics are suitable for use as standard particles for electron microscopy and powder particle size measurement, as well as for immunology, clinical testing, and spacers for microelectronics such as liquid crystals. Suitable for use in filter media evaluation tests, liquid chromatography, gas chromatography carriers, etc. EXAMPLES The present invention will be described in more detail with reference to Examples below. Measurements of various properties used in the Examples below were carried out as follows unless otherwise specified. (1) Specific gravity Specific gravity was measured according to the pycnometer method. (2) Standard deviation value of particle size and particle size distribution Take a scanning electron micrograph of the powder, and calculate the number of particles observed within the unit field of view of the photograph (n),
and the particle diameter (diameter X _i ), which is calculated using the following formula. Standard deviation value = X + σ _o /X However (3) Specific surface area Shibata Chemical Instruments Co., Ltd. Rapid surface measuring device SA−
1000 was used. The measurement principle is the BET method. (4) Sphericity Image analysis device connected to a scanning electron microscope (manufactured by Nippon Avionics, product name: EXCEL+
Circularity (Ci) was determined from a plane image of 20 arbitrary inorganic oxide particles using Image Command 98), and the number average of the values was taken as the sphericity. (However, n = 20) Example 1 Glass reactor with stirrer (inner volume 5)
Then, 1600 ml, 350 ml and 8 ml of methanol, aqueous ammonia (25% by weight) and 5N-NaOH aqueous solution were charged and mixed thoroughly to prepare a reaction solution. Note that the sodium ion concentration was approximately 20 mmol/. Next, a raw material solution was prepared by dissolving 205 g of tetraethyl silicate [Si(OC ₂ H ₅ ) ₄ , manufactured by Nippon Colcoat Chemical Co., Ltd., trade name: Ethyl silicate 28] in 1 methanol. Also, methanol, ammonia water (25% by weight)
and 700ml each of 5N-NaOH aqueous solution,
An alkaline solution for addition was prepared by mixing 200 ml and 100 ml. While maintaining the temperature of the reaction solution at 20° C., the above raw material solution was added dropwise to the reaction solution at a rate of 1 ml/min using a metering pump. Approximately 10 minutes after starting addition of raw material solution
Within minutes, the reaction solution began to become cloudy, and the sodium ion concentration in the reaction solution gradually decreased. After starting addition, approx. 2
The sodium ion concentration decreased to 5 mmol/in the course of time, and after this, the sodium ion concentration in the reaction solution decreased to 5 mmol/in and the water concentration decreased to 7.0 to 8.5 mol/in.
The above alkaline solution for addition was appropriately added dropwise until the reaction was stopped so that the ammonia concentration remained constant at 2.5 to 3.0 mol/. In addition, as a method to keep the sodium ion concentration in the reaction solution constant, measure the electrical conductivity in the reaction solution, and use a quantitative meter connected to an electrical conductivity controller to keep the electrical conductivity constant at 0.6 mS/cm. The additive alkaline solution was added intermittently by a pump. Approximately 30 hours after the start of the reaction, the particle size of the inorganic oxide particles in the reaction solution reached 3.0 μm, and the addition of the raw material solution and the alkaline solution for addition was stopped, and the reaction solution was allowed to stand still, allowing the inorganic oxide particles to settle. , the supernatant was separated. Furthermore, it was redispersed in methanol, subjected to decantation treatment, washed, and then observed with a scanning electron microscope. As a result, the particles were completely spherical, and the standard deviation value of the particle size was 1.019. 50g of the particles obtained above were mixed with 1600ml of methanol and 400ml of ammonia water (25% by weight).
The mixture was redispersed in a mixed solution to obtain a reaction liquid slurry. In addition, an ammonia solution for addition was prepared by mixing 800 ml of methanol, 200 ml of aqueous ammonia (25% by weight), and 10 ml of a 5N-NaOH aqueous solution. The raw material solution used had the same composition as the raw material solution described above. Next, the ammonia solution for addition is added into the reaction liquid slurry at a rate of 2 ml/min, and after about 30 minutes, the raw material solution is added at a rate of 1 ml/min in parallel with the ammonia solution for addition. did. Addition of the ammonia solution for addition is continued until the reaction is stopped, and the sodium ion concentration is 3.5 mmol/, and the water concentration is 7.5~
8.5mol/, ammonia concentration 2.5-3.0mol/
It was made to be constant. Approximately 48 hours after the start of addition of the raw material solution, the particle size of the inorganic oxide particles grew to 4.6 μm. Observation with a scanning electron microscope revealed that the obtained inorganic oxide particles were completely spherical, and the standard deviation value of the particle size was 1.017. Furthermore, when the above operation was repeated twice using the obtained particles with a particle size of 4.6 μm as seed particles, the particle size became 6.2 μm. Thereafter, the reaction solution was allowed to stand still, the inorganic oxide particles were allowed to settle, and the supernatant liquid was separated. Furthermore, the mixture was redispersed in methanol, the decantation process was repeated three times, methanol was removed using an evaporator, and the mixture was dried under reduced pressure at 120°C to obtain inorganic oxide particles as a powder. Observation results using scanning electron microscopy (first
), the shape of the powder is perfectly spherical, and its average particle size is
The particle diameter was 6.23 μm, and the standard deviation value of the particle size was 1.015. Also, the specific surface area by BET method is 1 m ² /g
It was below. According to X-ray analysis, approximately 2θ=25°
A gentle mountain-shaped absorption was observed around , and it was confirmed that the material had an amorphous structure. Furthermore, thermal changes and weight changes were measured using a differential thermal analyzer and a thermobalance. The result is 100-200℃
There was an endotherm and weight loss that was thought to be due to dehydration, and furthermore, there was an exothermic weight loss around 200-650°C. Thereafter, almost no thermal or weight changes were observed up to 1000°C. In addition, the content of Na ₂ O by atomic absorption spectrometry is
6.8mol%, the specific gravity of the particles is 2.12, and the sphericity is
At 1.00, it was a perfect sphere. Table 1 shows the sodium ion concentration in the reaction solution that was kept constant during the reaction and the number of times the seed particles regrown.
Inorganic oxide particles were produced under the same conditions as in Example 1 except for the values shown in . The results were as shown in Table 1.

[Table] Example 2 All conditions were the same as in Example 1, except that a 4N-KOH aqueous solution was used instead of the 5N-NaOH aqueous solution in the reaction solution, the alkaline solution for addition, and the ammonia solution for addition. carried out. Table 2 shows the results.

[Table] Example 3 0.1% hydrochloric acid and tetraethyl silicate [Si(OC ₂ H ₅ ) ₄ , manufactured by Nippon Colcoat Chemical Co., Ltd., trade name: ethyl silicate 28] were added at a ratio of 3 g and 130 g to 1 methanol, respectively. mix,
This solution was hydrolyzed at room temperature with stirring for about 2 hours. Thereafter, this was added to a solution of 34 g of tetrabutyl titanate [Ti(O-nC ₄ H ₉ ) ₄ , manufactured by Nippon Soda] dissolved in 420 ml of isopropanol while stirring, and the hydrolyzate of tetraethyl silicate and tetrabutyl titanate were combined. A mixed solution was prepared and used as a raw material solution. Next, inorganic oxide particles (containing Na ₂ O) having an average particle diameter of 2.5 μm produced in the same manner as in Example 1 were used as seed particles, and the seed particles were regrown using the above raw material solution. The operation for growing the seed particles was carried out under the same conditions as in Example 1, except that the above raw material solution was used. Further, in the above operation, all procedures were carried out in the same manner as above except that 34 g of tetrabutyl titanate was changed to the raw materials shown in Table 3. The results are shown in Table 3.

【table】 [Brief explanation of the drawing]

FIG. 1 is a scanning electron micrograph showing the morphology of the inorganic oxide particles of the present invention obtained in Example 1.

Claims (1)

[Claims] 1 The main constituents are silica and an oxide of a metal from group 3 of the periodic table, and the particle size is 1.5 to 20 μm,
Spherical inorganic oxide particles having a standard deviation value of particle diameter in the range of 1.00 to 1.10.