JP2727589B2 - Large particle size almonium pentoxide sol and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a particle having a regular octahedral structure and a particle diameter of
It relates to a stable large particle size antimony pentoxide sol in the range of 40-300 mμ.

(Prior Art) Known antimony pentoxide sols obtained by the following method are known.

A method of deionizing an alkali salt of antimonic acid with an ion exchange resin (Japanese Patent Publication No. 52-21298, U.S. Pat.
No. 47), a method of oxidizing antimony trioxide with hydrogen peroxide at a high temperature (JP-B-53-20479, JP-A-52-21298)
JP-A-52-123997) or a method of pulverizing an alkali antimonate after reacting the same with an inorganic acid (JP-A-60-123997).
-41536, JP-A-61-227918). The particle size of the antimony pentoxide sol obtained by these methods is 5 to 10
In the range of 0 μm, the particle size distribution is fairly wide, and although the crystal is a crystal by X-ray diffraction, it does not show a clear crystal shape by observation with a transmission electron microscope.

(Problems to be Solved by the Invention) The above-mentioned conventional antimony pentoxide sol is used for various applications by utilizing its fine particle characteristics. However, in practical use, a high concentration is required, so that organic amine is used as a stabilizer. Often added. When used in the form of a mixture with an emulsion or aqueous solution of various resins or an organic solvent solution, a surface modifier is often added to improve the dispersibility and compatibility during mixing. The conventional antimony pentoxide sol has a small particle size of 5 to 100 mμ, and also has a large specific surface area due to low crystallinity and high surface activity,
These stabilizers and surface modifiers must be used in a large amount, which leads to deterioration of the resin and disadvantages such as poor weather resistance. In addition, when the antimony pentoxide sol is dried and used as a powder, the particles of the conventional antimony pentoxide sol form cohesive bonds during drying, so that the primary particles are re-used at the time of use except when redispersed in water. Is difficult to disperse. For this reason, the inherent characteristics of fine particles are often not utilized.

The above-mentioned problems can be solved by increasing the particle size of the antimony pentoxide colloidal particles, reducing the specific surface area by increasing the crystallinity, and decreasing the surface activity. As a result of
The present inventors have found a method for producing an antimony pentoxide sol having high crystallinity and a large particle diameter of antimony pentoxide colloid particles.

An object of the present invention is to provide an antimony pentoxide sol in which the specific surface area is reduced by increasing the particle size of antimony pentoxide colloidal particles and increasing the crystallinity.

(Means for Solving the Problems) That is, the present invention relates to a large-particle-diameter antimony pentoxide sol having a particle shape having a regular octahedral structure and a particle diameter in a range of 40 to 300 mμ.

The large particle size antimony pentoxide sol of the present invention comprises the following (A) to (C) (A) alkali antimonate in a stoichiometric ratio of 0.7 to 5:
Reaction with double amount of monovalent or divalent inorganic acid to form antimony pentoxide gel, (B) Then, the gel is separated and washed with water to obtain wet cake. (C) This wet cake is treated with antimony pentoxide sol. And a step of mixing and heating.

The alkali antimonate used in the step (A) of the present invention is represented by the general formula MSb (OH) ₆ , wherein M is Na,
K represents an alkali metal. As the alkali metal, sodium is preferable, and particularly, sodium antimonate hydrate Na
_{2 O · Sb 2 O 5 ·} 6H 2 O (NaSb (OH) 6: Sb 2 O 5 63~65 wt%, Na
2O12~13 wt%, H ₂ O23~24 wt%) is preferred.

Acids that can be used in the step of producing antimony pentoxide gel by the reaction of alkali antimonate and acid in step (A) of the present invention are monovalent or divalent inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid, and sulfamic acid. is there. Since phosphoric acid has almost the same acid strength as antimonic acid (HSb (OH) ₆ ), an antimony pentoxide gel cannot be obtained. If the acid strength is low, for example, formic acid, oxalic acid, etc., the desired antimony pentoxide gel cannot be obtained.

Antimony concentrations alkali in the reaction of antimonate alkali and the acid of the above step (A) can be 2 to 40% by weight of anhydrous antimony pentoxide in the reaction solution (Sb ₂ O _5). When the content is less than 2% by weight, the production amount of antimony pentoxide gel is reduced, so that it is not economical. If it exceeds 40% by weight, the solid content in the reaction solution exceeds 60% by weight, and the reaction tends to be uneven. Preferably, it is 6 to 30% by weight as anhydrous antimony pentoxide.

In the reaction between the alkali antimonate and the acid in the step (A), the concentration of the acid is such that the acid / alkali antimonate is in a stoichiometric ratio of 0.5 to 5, preferably 1 to 3.
It is. If the stoichiometric ratio is less than 0.5, the desired antimony pentoxide gel cannot be obtained even if the reaction temperature and alkali antimonate concentration are increased. On the other hand, if the stoichiometric ratio exceeds 5, the produced antimony pentoxide gel is peptized at the time of washing, and the sol flows out into the filtrate, resulting in poor productivity.

The reaction temperature in the above step (A) is from room temperature to 100 ° C., and the reaction time can be 0.5 to 15 hours. In order to obtain an antimony pentoxide sol having a good shape and a narrow flow rate distribution, the reaction temperature is preferably 50 ° C. or lower and the reaction time is preferably 10 hours or less. The reaction temperature exceeds 50 ° C and the reaction time is 15
When the time is longer than the time, the shape of the obtained large particle diameter antimony pentoxide sol tends to be distorted.

Next, the antimony pentoxide gel obtained in the step (A) is separated and washed with water. In the step (B), a wet cake of the antimony pentoxide gel is obtained.

The fine antimony pentoxide colloid produced by the reaction in the step (A) is remarkably agglomerated due to the acid and the alkali metal salt thereof in the system, and forms an antimony pentoxide gel (usually particles of 3 μ or more) to form a reaction. The gel slurry obtained in the step (A) is subjected to pressure (suction) because the gel precipitates quickly in the liquid.
It can be separated very easily by a method such as filtration or centrifugal filtration. After filtration, washing is required to remove the coexisting acid and its alkali metal salt. At the time of washing, partial hydrolysis of the antimony pentoxide gel may be promoted by contact with a large amount of water, and partial deflocculation may also occur. Injection washing must be performed promptly with 4 times the amount of water.

Incidentally, the amount of antimony pentoxide that flows into the filtrate by filtration and washing in the method of the present invention is 3% by weight or less.

The wet cake of antimony pentoxide gel obtained by the filtration and washing in the above step (B) has a water content of 30 to 40% by weight.
Most of which is water of crystallization.

The five X-ray diffraction pattern of the antimony oxide gel the same as antimony pentoxide hydrate _{(Sb 2 O 5 · 4H 2} O), X -ray diffraction pattern of the antimonate alkali material is not permitted.

The antimony pentoxide gel obtained in the step (B) is mixed with an antimony pentoxide sol and heated. In the step (C), an antimony pentoxide sol having a large particle diameter is obtained. As the antimony pentoxide sol used in the step (C), those produced by any of the above methods can be used, but those produced by an ion exchange method or a peptization method are preferable. Furthermore,
By repeatedly using the antimony pentoxide sol obtained in the above steps (A) to (C) as the antimony pentoxide sol used in the step (C), it was obtained in the first steps (A) to (C). The particle size can be made larger than the particle size of antimony pentoxide.

In the step (C) of the present invention, the antimony pentoxide gel is pulverized by heating in the presence of an organic base and / or phosphoric acid in a state of being dispersed in water to form fine antimony pentoxide colloid particles. However, this is bonded to the surface of the colloidal particles of the antimony pentoxide sol coexisting to cause particle growth, so that an antimony pentoxide sol having a large particle diameter is generated.

Therefore, the higher the ratio of the antimony pentoxide gel to the antimony pentoxide sol at the time of charging in the step (C), the larger the sol having a larger particle diameter is obtained. In such a case, the gel is peptized. Requires the addition of an organic base and / or phosphoric acid.

Examples of the organic base usable herein include amines such as n-propylamine, benzylamine, triethanolamine, tripropanolamine, diethanolamine, monoethanolamine, N-ethylaminoethanolamine, tetraethanolammonium hydroxide, monomethyltrimethylamine, and the like. Examples include quaternary ammonium hydroxides such as ethanol ammonium hydroxide, and organic bases such as guanidine hydroxide. Bases such as sodium hydroxide, potassium hydroxide, and ammonia are unsuitable because they are incorporated into the antimony pentoxide structure, causing only partial peptization.

The amount of the organic base to be added is [base] / [Sb ₂ O
₅ ] is 0.5 or less, preferably 0.2 or less. If the stoichiometric ratio exceeds 0.5, the amount of free organic base which is peptized but not adsorbed by the colloid particles increases, thereby causing the above-mentioned adverse effects such as deterioration of physical properties of the resin and deterioration of weather resistance.

Further, as the phosphoric acid usable here, orthophosphoric acid,
Examples thereof include pyrophosphoric acid, metaphosphoric acid, triphosphoric acid, and tetraphosphoric acid, and orthophosphoric acid is most preferable.

In the present invention, since phosphoric acid is strongly adsorbed on antimony pentoxide gel and is not removed even by washing, it shows exactly the same effect as when phosphoric acid is added during the reaction of alkali antimonate and inorganic acid, when pulverized. . Similarly, phosphoric acid can be added both during the reaction and during the peptization. The amount of phosphoric acid added is 5% or less in P ₂ O ₅ / Sb ₂ O ₅ % by weight in either case of adding during the reaction, adding during peptization, or adding both. Preferably it is 2% or less. If the added amount exceeds 5% by weight, peptization occurs, but particle growth does not sufficiently occur, and an undesirably small particle sol is formed.

When adding both an organic base and phosphoric acid, each can be added within the above-mentioned range. Further, these peptizing aids may be contained in advance in antimony pentoxide sol serving as a core, or may be added when mixing and heating antimony pentoxide gel and antimony pentoxide sol.

In the step (C) of the present invention, the temperature for growing the particles is from room temperature to 250 ° C. Although heating by an autoclave is also possible, it is not economical and preferably 50 to 100 ° C.
When an organic base is added as a peptizing aid, the closer to 100 ° C. as much as possible, the better the crystallinity of the grown colloidal particles and the smaller the specific surface area. Observation of the obtained large particle diameter antimony pentoxide sol with a transmission electron microscope shows that when the particles grow at approximately 90 ° C. or less, the colloidal particles are derived from the fine colloidal particles in the antimony pentoxide gel. In contrast to the apparent irregularities, when the particles were grown at 90 ° C. or higher, the surface of the colloidal particles was found to be smooth and to have an accurate regular octahedral structure.

Generally, an antimony pentoxide sol having high crystallinity can be obtained by heating the antimony pentoxide sol to 100 ° C. or higher. This is because dehydration condensation proceeds at a temperature of 100 ° C. or more to form a single crystal.

In the present invention, active microcolloid particles are bonded to antimony pentoxide colloid particles serving as nuclei, dehydration condensation proceeds, single crystallization proceeds, the shape becomes a regular octahedron, and the microcolloids grow epitaxially on the octahedron. It seems to go.

In the present invention, in order to obtain an antimony pentoxide sol having a larger particle size, it is necessary to increase the ratio of the antimony pentoxide gel to the antimony pentoxide sol in the step (C). If the whole amount of the antimony oxide gel is added to the antimony pentoxide sol at a time and heated, not only particle growth does not occur uniformly but also small particles independent of freshness are generated, so that the particle size distribution becomes very wide, which is not preferable.

Therefore, in order to obtain a large particle sol having a narrow particle size distribution and high crystallinity, in the step (C), the antimony pentoxide gel is added little by little into the heated antimony pentoxide sol and the particles grow slowly. Is preferred. As a method for this, it is advantageous that the antimony pentoxide gel is dispersed in water to form a slurry, and the slurry is added intermittently or continuously using a metering pump such as a tube pump because of good operability. When this slurrying method is employed, an organic base and / or phosphoric acid can be added to the slurry. The concentration of the antimony pentoxide sol as a core is 0.04 as anhydrous antimony pentoxide (Sb ₂ O ₅ ).
1-40% by weight is possible. If the content of antimony pentoxide gel to the antimony pentoxide sol (Sb ₂ O ₅ weight ratio) is less than 0.01% by weight, the concentration of the finally obtained sol becomes 2% by weight or less, which is not economical. ,
Conversely, if it exceeds 40% by weight, the particle growth becomes non-uniform and small particles are easily formed, which is not preferable.

The amount of antimony pentoxide gel to be added is such that anhydrous antimony pentoxide (Sb ₂ O
₅ ) The ratio is 0.3 to 100, preferably 1 to 50
It is. If it is less than 0.3, particle growth does not occur so that the crystallinity of the produced sol becomes sufficiently high, and the particle diameter is only about 10% larger than that of the nuclear sol, so that a sufficient effect cannot be obtained. On the other hand, if it exceeds 100, addition of the whole amount of antimony pentoxide gel in a relatively short time makes the particle growth non-uniform, and also generates new small particles and broadens the particle size distribution. The antimony pentoxide gel is slowly added so that the uniformity occurs, and during this time, the colloidal particles in the antimony pentoxide gel undergo dehydration condensation between themselves and grow into particles. However, they no longer contribute to the particle growth of the nuclear sol and form independent particles. Therefore, sufficient particle growth does not occur, and the particle size distribution is widened, which is not preferable.

This change with time of the antimony pentoxide gel occurs similarly whether or not the antimony pentoxide gel is slurried, and if it is slurried, whether or not an organic base and / or phosphoric acid is added. It is a phenomenon. Therefore, it is not preferable to store the antimony pentoxide gel wet cake for a long time.

The concentration of the large particle diameter antimony pentoxide sol obtained in the present invention can be 2 to 60% by weight as anhydrous antimony pentoxide (Sb ₂ O ₅ ), but the higher the concentration, the more uneven the particle growth. The content is preferably 30% by weight or less because it easily occurs. When the concentration of the sol obtained by particle growth is 2 to 30% by weight, a high concentration sol of 30 to 60% by weight can be easily obtained by concentrating by an evaporation method, an ultrafiltration method, a reverse osmosis method, or the like. Can be. If the concentration is less than 2% by weight, the cost of concentration increases and it is not economical. If the concentration exceeds 60% by weight, the viscosity of the sol increases, which is not preferable. With conventional sols, it was difficult to increase the concentration to 55% by weight or more due to thickening.
The large particle size antimony pentoxide sol of the present invention has an advantage that a sol having a concentration of 60% by weight can be obtained without significantly increasing the viscosity.

As described above, the antimony pentoxide sol having a large particle diameter obtained by the method of the present invention can be used as the antimony pentoxide sol used in the step (C) of the present invention to further increase the particle diameter. The range that can be increased by this repetitive operation is approximately 300 mμ.

The pH of the large particle size antimony pentoxide sol of the present invention is 1.5 to 1
It is in the range of 0.5. When an organic base is added as a peptizing aid, the sol is passed through a column filled with a cation exchange resin, so that the organic base-free pH can be easily obtained.
It can be 1.5 to 4 sols. The dried product of this sol has a very sharp X-ray diffraction peak.

Next, the present invention will be described in more detail by way of examples. However, the present invention is not limited by these examples.

Incidentally,% referred in the following examples are by weight%, sodium antimonate used is _{Sb 2 O 5 65%, Na} 2 O12.5%, H 2 O2
It has a composition of 2.5%.

Comparative Example 1 400 g of sodium antimonate was dispersed in 431 g of water, and 209 g of 35% hydrochloric acid was added with stirring. This slurry was heated to 30 ° C. and reacted for 4 hours. The concentration of antimony pentoxide in the reaction solution was 25.0%, and the equivalent ratio of hydrochloric acid / sodium antimonate was 1.
25. Next, the antimony pentoxide gel slurry produced by the reaction was filtered by suction, and 1500 g of pure water was injected to wash. 410 g of the obtained antimony pentoxide gel wet cake was dispersed in 1595 g of water, and then 85% orthophosphoric acid 5.3 g
After adding g, the temperature was raised to 80 ° C. and peptization was performed for 2 hours.
The addition amount of phosphoric acid was 1.27% by weight of P ₂ O ₅ / Sb ₂ O ₅ , and there was no unpeptized substance.

The resulting sol had a specific gravity of 1.137, pH 2.61, viscosity 2.5 cp, and Sb
_{2 O 5 12.8%, P 2} O 5 0.16%, particle diameter 20～25Emumyu, specific surface area 5
It was 5.9 m ² / g.

Example 1 410 g of an antimony pentoxide gel wet cake obtained by performing a reaction and filtering and washing under the same conditions as in Comparative Example 1 was mixed with 45 parts of water.
3 g, and 5.2 g of 85% orthophosphoric acid (equivalent to 1.24% by weight of P ₂ O ₅ / Sb ₂ O ₅ ) was added to form a slurry. The concentration of antimony pentoxide in this slurry was 29.6%,
The P ₂ O ₅ concentration is 0.37%.

Separately, 440 g of the sol having a particle diameter of 20 to 25 mμ obtained in Comparative Example 1 was added to water 4.
50 g was added to make 6.3% Sb ₂ O ₅ sol, and the temperature was raised to 85 ° C.
Here, the above-mentioned slurry was added in six portions at intervals of 20 minutes each of 145 g. During this time, the liquid temperature was kept at 80 to 85 ° C., and after adding the whole amount of the slurry, the solution was kept at 85 ° C. for 2 hours to complete the peptization. Of Sb ₂ O ₅ in the slurry, the ratio Sb ₂ O ₅ in the nucleus sol is 4.6.

The resulting sol had a specific gravity of 1.202, pH 2.12, viscosity of 6.4 cp, and Sb ₂ O
_{5 17.8%, P 2 O 5} 0.22%, particle diameter 40～60Emumyu, specific surface area 31.9
m ² / g. This sol was stable even after storage at 50 ° C. for one month without any increase in viscosity or formation of sediment.

Example 2 410 g of an antimony pentoxide gel wet cake obtained by performing a reaction and filtering and washing under the same conditions as in Comparative Example 1 was mixed with 49 parts of water.
The mixture was dispersed in 5 g, and 5.2 g of 85% orthophosphoric acid (equivalent to 1.24% by weight ratio of P ₂ O ₅ / Sb ₂ O ₅ ) was added to form a slurry. The concentration of antimony pentoxide in this slurry is 28.3%,
The P ₂ O ₅ concentration is 0.35%.

Separately, 450 g of the sol having a particle diameter of 35 to 50 mμ obtained in Example 1 was added to water 3
50 g was added to obtain a 10.0% Sb ₂ O ₅ sol, and the temperature was raised to 85 ° C.
Here, 182 g of the above-mentioned slurry was added in five portions at 20 minute intervals. During this time, the liquid temperature was kept at 80 to 85 ° C., and after adding the whole amount of the slurry, the solution was kept at 85 ° C. for 2 hours to complete the peptization. Of Sb ₂ O ₅ in the slurry, the ratio Sb ₂ O ₅ in the nucleus sol is 3.2.

The obtained sol had a specific gravity of 1.235, pH 2.22, viscosity of 3.7 cp, and Sb ₂ O
₅ 20.2%, P ₂ O ₅ 0.25%, particle size 60-80mμ, specific surface area 20.1
m ² / g. This sol was stable even after storage at 50 ° C. for one month without any increase in viscosity or formation of sediment.

Example 3 350 g of sodium antimonate was dispersed in 1393 g of water, and 325 g of 35% hydrochloric acid was added with stirring. The slurry was kept at 25 ° C. and reacted for 3 hours. The concentration of antimony pentoxide in the reaction solution was 11.0%, and the equivalent ratio of hydrochloric acid / sodium antimonate was 2.
22. Next, the antimony pentoxide gel slurry produced by the reaction was filtered by suction, and 1000 g of pure water was injected to wash. As a result, 370 g of an antimony pentoxide gel wet cake was obtained. 37g of this wet cake
Is dispersed in 613 g of water, then triethanolamine 0.46
g (equivalent to a stoichiometric ratio of triethanolamine / Sb ₂ O _{5 of} 0.045) was added, and the mixture was heated to 90 ° C. and peptized to obtain an antimony pentoxide sol.

This sol has a specific gravity of 1.035, pH 3.50, viscosity of 1.4 cp, and Sb ₂ O
₅ 3.4%, triethanolamine 0.07%, particle size 20-40m
μ.

Disperse the remaining 333 g of wet cake in 1240 g of water,
Then, 4.1 g of triethanolamine (corresponding to a stoichiometric ratio of triethanolamine / Sb ₂ O _{5 of} 0.044) was added to form a slurry. The concentration of antimony pentoxide in the slurry is 1
2.7%, triethanolamine concentration is 0.26%.

The slurry is mixed with the above sol having a particle size of 20 to 40 μm by 90.
While maintaining at 0 ° C, the mixture was added at a constant rate of 7.5 g / min using a tube pump over 3.5 hours. After slurry addition 30
The mixture was kept at 90 ° C. for minutes to complete the peptization.

The obtained sol had a specific gravity of 1.107, pH 5.68, viscosity of 1.7 cp, and Sb ₂ O
₅ 10.0%, triethanolamine 0.21%, particle size 60-90m
μ, specific surface area was 16.2 m ² / g, and the particles had a regular octahedral structure when observed with a transmission electron microscope.

Example 4 370 g of an antimony pentoxide gel wet cake obtained by carrying out a reaction and filtration and washing under the same conditions as in Example 3 was mixed with water 12
Then, 4.6 g of triethanolamine (equivalent to a stoichiometric ratio of triethanolamine / Sb ₂ O _{5 of} 0.045) was added to form a slurry. The antimony pentoxide concentration in the slurry is 14.2% and the triethanolamine concentration is
0.29%.

Separately, 230 g of the sol having a particle diameter of 60 to 90 mμ obtained in Example 3 was added to water 4 g.
20 g was added to obtain a 3.5% Sb ₂ O ₅ sol, and the temperature was raised to 90 ° C.
Here, 7.5 g of the above slurry using a tube pump
At a constant rate of / min over 3.5 hours. When adding the slurry, maintain the liquid temperature at 90 ° C.
The mixture was kept at 90 ° C. for minutes to complete the peptization. Sb in slurry
_The ratio of ₂ O ₅ to Sb ₂ O ₅ in the nuclear sol is 9.7.

The obtained sol had a specific gravity of 1.122, a pH of 5.58, a viscosity of 1.7 cp, and Sb ₂ O
₅ 11.1%, triethanolamine 0.23%, particle size 120-17
The particle size was 0 mμ, the specific surface area was 11.6 m ² / g, and the particles had a regular octahedral structure as in Example 3 when observed with a transmission electron microscope.

Example 5 370 g of an antimony pentoxide gel wet cake obtained by performing a reaction and filtering and washing under the same conditions as in Example 3 was converted into a slurry under the same conditions as in Example 4.

And Sb ₂ O ₅ 5.9% of sol water 305g was added to the sol 345g particle size 100~150mμ was separately obtained in Example 4 was heated to 90 ° C.. Here, the above-mentioned slurry is
It was added at a constant rate of 7.5 g / min over 3.5 hours. When adding the slurry, keep the liquid temperature at 90 ° C, and after adding the slurry
The mixture was kept at 90 ° C. for 30 minutes to complete the peptization. In the slurry
The ratio of Sb ₂ O ₅ to Sb ₂ O ₅ in the nuclear sol is 5.8.

The obtained sol had a specific gravity of 1.126, pH 5.94, viscosity of 1.6 cp, and Sb ₂ O
₅ 11.7%, triethanolamine 0.24%, particle size 170 ~ 24
The particles had a specific surface area of 8.2 m ² / g, and were observed by a transmission electron microscope. As a result, the particles had a regular octahedral structure as in Example 5.

Comparative Example 2 Of 370 g of antimony pentoxide gel wet cake obtained by performing a reaction and filtration and washing under the same conditions as in Example 3,
2.3 g dispersed in 600 g water, then triethanolamine
0.08 g (corresponding to a stoichiometric ratio of triethanolamine / Sb ₂ O _{5 of} 0.12) was added, and the mixture was heated to 90 ° C. and peptized to obtain an antimony pentoxide sol.

This sol has a specific gravity of 1.003, pH 3.80, viscosity of 1.2 cp, Sb ₂ O
₅ 0.23%, triethanolamine 0.013%, particle size 20-30
mμ.

The remaining 367.7 g of the wet cake was dispersed in 1200 g of water, and then 4.5 g of triethanolamine (equivalent to a triethanolamine / Sb ₂ O ₅ stoichiometric ratio of 0.043) was added to form a slurry. The concentration of antimony pentoxide in the slurry is 14.4%, and the concentration of triethanolamine is 0.29%.
This slurry is heated at 90 ° C.
Was added over 1 hour at a constant rate of 26 g / min using a tube pump. 1 hour after completion of slurry addition 90
C. to complete the peptization. Sb ₂ O in slurry
_The ratio of ₅ to Sb ₂ O ₅ in the nuclear sol is 160.

The obtained sol had a specific gravity of 1.110, a pH of 5.69, a viscosity of 1.6 cp, and Sb ₂ O
₅ 10.3%, triethanolamine 0.21%, particle size 20-150
mμ, specific surface area was 14.4 m ² / g. When observed with a transmission electron microscope, most of the particles had a regular octahedral structure, but a large number of irregularly shaped small particles were also found.

Comparative Example 3 Antimony trioxide (average particle diameter: 3μ) 164 in 1200 g of water
The slurry obtained by adding 6.6 g and 965.2 g of 31% aqueous hydrogen peroxide with stirring was added to 2479.4 g of boiling water using a tube pump over 2 hours. The boiling state was maintained during the addition of the slurry, and 90 ° C. was further maintained for 2 hours after the addition was completed.

The obtained sol had a specific gravity of 1.377, a pH of 1.8, a viscosity of 7.2 cp, and Sb ₂ O ₅
The particle size was 30.0% and the particle size was 30 to 80 mμ. When observed with a transmission electron microscope, the particles had an irregular shape with many irregularities.

(Measurement of crystallinity)

As a measure of the crystallinity of the antimony pentoxide particles in the sols obtained in Examples 1 to 5 and Comparative Examples 1 and 3, the half width of the X-ray diffraction peak of the dried product of the antimony pentoxide sol was measured. The measured peak is 2θ due to diffraction of the (111) plane.
= 15.8 ° peak.

 Half width (2θ ゜) Example 1 0.272 Example 2 0.226 Example 3 0.215 Example 4 0.164 Example 5 0.181 Comparative example 1 0.364 Comparative example 2 0.458

[Brief description of the drawings]

FIGS. 1, 2, and 3 are electron micrographs of antimony pentoxide particles in the antimony pentoxide sols produced according to Examples 3, 4, and 5, respectively. FIGS. 4 and 5 are electron micrographs of antimony pentoxide particles in the antimony pentoxide sols produced in Comparative Examples 2 and 3, respectively. The magnification is 200,000. FIGS. 6, 7, 8 and 9 are diffraction diagrams of peak portions at 2θ = 15.8 ° in X-ray diffraction measurements of powders obtained from the antimony pentoxide sols of Examples 2 and 5 and Comparative Examples 1 and 3, respectively. .

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-52-21298 (JP, A) JP-A-61-227918 (JP, A)

Claims (5)

(57) [Claims] (1) The particle shape has a regular octahedral structure, and the particle size is
A large particle size antimony pentoxide sol having a size in the range of 40 to 300 mμ. 2. The following (A) to (C) (A) alkali antimonate is used in a stoichiometric ratio of 0.7 to 5:
(B) Then, the gel is separated and washed with water to obtain a wet cake. (C) The wet cake is mixed with the antimony pentoxide sol. And a step of heating the mixture. 3. The method according to claim 2, wherein an organic base and / or phosphoric acid is added when the wet cake and the antimony pentoxide sol are mixed and heated in the step (C). 4. When mixing and heating the wet cake and the antimony pentoxide sol in the step (C), the wet cake is dispersed in water to form a slurry, and intermittently or continuously in the heated antimony pentoxide sol. Claim 2
A method for producing the large particle diameter antimony pentoxide sol described in the above. 5. The antimony pentoxide sol obtained from the above steps (A) to (C) is used as the antimony pentoxide sol when mixing and heating the wet cake and the antimony pentoxide sol in the step (C). A method for producing the large particle size antimony pentoxide sol according to claim 2.