JP2003026417A - Method for producing silica sol and silica-based composite oxide sol - Google Patents

Abstract

(57) [Summary] [Problem] To be excellent in production efficiency, fast in particle growth rate,
A silica sol and a silica-based composite oxide sol having a uniform and stable particle diameter are produced. SOLUTION: An alkali silicate aqueous solution is added to a core particle dispersion or an alkali silicate aqueous solution in the presence of an electrolyte to grow core particles, thereby producing a silica sol. In addition, in the presence of an electrolyte in a nuclear particle dispersion or an aqueous solution of an alkali silicate,
An aqueous solution of an alkali silicate and an aqueous solution of a metal salt or a non-metal salt other than silicon are added to grow core particles, thereby producing a silica-based composite oxide sol. The electrolyte comprises a salt of a strong acid, and the ratio (E _A ) of the number of equivalents (E _A ) of the alkali in the supplied alkali silicate to the number of equivalents (E _E ) of the electrolyte.
/ E _E ) is preferably in the range of 0.5 to 8.
After the addition of the alkali silicate aqueous solution, the mixture is aged in a temperature range of 40 to 150 ° C. for 10 minutes to 3 hours. The mixture was deionized to reduce the amount of residual anions to Si.
The content may be 0.01% by weight or less of O ₂ .

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a silica sol and a silica-based composite oxide sol by utilizing the particle growth of core particles.

[0002]

Inorganic oxide sols such as silica sol, alumina sol, titania sol, silica alumina sol, silica zirconia sol are plastic admixtures, film fillers, refractive index adjusting materials, transparent base material coating materials, various binders, and polishing particles. , Filler for inkjet receiving layer, etc.
It is used for various purposes. As a method for producing the above-mentioned inorganic oxide sol, the applicant of the present application has disclosed in Japanese Patent Laid-Open No. 63-64911 that an acidic silicic acid solution (silicic acid obtained by dealkalizing alkali silicate) is added to a dispersion of core particles to form a core. It is disclosed that, when growing particles, if the core particles become large, the sol having a uniform particle size distribution can be obtained by decreasing the addition rate of the acidic silicic acid solution. In addition, JP-A-5-
Japanese Laid-Open Patent Publication No. 132309 similarly discloses a method for producing a composite oxide sol. However, in the conventional method for producing a silica sol, when the acidic silicic acid solution is supplied to grow the core particles, it is not possible to increase the supply rate of the acidic silicic acid solution because the solubility of silica is low. As the diameter increases, the surface area of the core particles decreases in inverse proportion to this, and the silica deposition rate of the acidic silicic acid solution decreases. On the other hand, when the supply speed of the acidic silicic acid solution is increased, fine particles are generated in addition to the core particles, resulting in a problem that the particle diameter of the obtained sol becomes nonuniform, the stability decreases, and in some cases gelation occurs. there were.

The acidic silicic acid solution is obtained by dealkalizing alkali silicate using an ion exchange resin or the like. At this time, if the concentration of silicic acid exceeds 5 to 7% by weight as SiO ₂ , it becomes unstable. However, there are restrictions on the production and use of silicic acid solutions. Further, it has been pointed out that the above-mentioned ion exchange resin is regenerated and used, so that the production efficiency is low. JP-A-58-110417 discloses that a soluble salt of an alkali metal is 40 to 1000 ppm.
A method for producing a silica sol composed of silica particles having a desired particle size and a uniform particle size distribution by using an existing active acidic silica sol (that is, an acidic silicic acid solution) is disclosed. However, this method also has to produce an active acidic silica sol as described above, and the production efficiency is not always satisfactory.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing a silica sol and a silica-based complex oxide sol which have excellent production efficiency, a high particle growth rate, a uniform particle size, and a stable particle size. It is a thing.

[0005]

A method for producing a silica sol or a silica-based composite oxide sol according to the present invention is characterized in that solution II is added to solution I described below in the presence of an electrolyte to grow core particles. To do. Solution I: Nuclear particle dispersion or aqueous solution of alkali silicate Solution II: Aqueous solution of alkaline silicate or aqueous solution of alkaline silicate and aqueous solution of metal salt or non-metal salt other than silicon The electrolyte comprises a salt of a strong acid and is supplied by an alkali silicate solution. number of equivalents of alkali in (E _a) and the number of equivalents of said electrolyte (E _E) of the ratio _{(E a} / E E) is 0. 5
It is preferably in the range of 8. After adding the liquid II, it is preferable to age the mixed liquid for 10 minutes to 3 hours in the temperature range of 40 to 150 ° C. It is preferable to deionize the mixed solution so that the amount of residual anions is 0.01% by weight or less of SiO ₂ . It is preferable to use the silica sol or the silica-based composite oxide sol obtained by any one of the methods described above as the core particle dispersion liquid. It is preferable to replace the silica sol or the silica-based composite oxide sol obtained by the method described above with an organic solvent.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a silica sol and a silica-based composite oxide sol according to the present invention will be specifically described below.

[Liquid I] As the core particle dispersion liquid, a conventionally known silica sol, alumina sol, or other fine particle dispersion sol of metal oxide can be used. Further, the core particle dispersion liquid can be prepared by diluting or neutralizing alkali silicate, sodium aluminate, and the like. Such silica sol is disclosed in Japanese Patent Application Laid-Open No. 63-64911 filed by the applicant of the present application.
The silica sol obtained by the method described in JP-A No. 2003-242242, or a dispersion liquid of silica particles having a relatively small particle size used as seed particles at this time can be preferably used. The particle size of the core particles depends on the particle size of the sol to be finally obtained and is not particularly limited, but is preferably 100 nm or less, and more preferably 50 nm or less. When the particle size of the core particles exceeds 100 nm, the time required to obtain the core particles themselves generally becomes long, and the effect of shortening the manufacturing time cannot be obtained. The lower limit of the particle size is not particularly limited as long as it functions as a core particle, but it is preferably an oligomer of silicic acid or more, and particularly a decamer or more.

The concentration of the core particle dispersion varies depending on the particle size of the core particles, but is preferably in the range of 0.005 to 10% by weight, more preferably 0.01 to 5% by weight as an oxide. When the concentration of the core particle dispersion liquid is less than 0.005% by weight, the core particles are too small and it is necessary to slow down the supply rate of the alkaline silicate aqueous solution. , The particle size distribution of the obtained sol may become broad because it acts as a core particle. If the concentration of the core particle dispersion exceeds 10% by weight, the core particles may coagulate when the alkaline silicate aqueous solution is supplied because the concentration is too high. In this case as well, the particle size distribution becomes broad and the particles adhere to each other. The particles tend to form.

The pH of the core particle dispersion is 8-12, especially 9.
It is desirable to be in the range of 5 to 11.5. When the pH is less than 8, the reactivity of the surface of the core particles is low, and the rate at which the supplied alkali silicate deposits on the surface is slow, and therefore unreacted alkali silicate increases or new fine particles are generated. Since this acts as a core particle, the particle size distribution of the obtained sol may become broad or agglomerated particles may be obtained. If the pH exceeds 12, the solubility of silica will be high and the precipitation of silica will be delayed, which tends to delay the particle growth. The pH of the nuclear particle dispersion liquid is adjusted by adding an alkali, and an alkali metal hydroxide such as NaOH or KOH, ammonia water, a quaternary ammonium hydroxide or an amine compound can be used. The temperature of the dispersion liquid at the time of preparing the core particle dispersion liquid is not particularly limited and is usually in the range of 10 to 30 ° C.

In the present invention, an aqueous solution of alkali silicate such as sodium silicate or potassium silicate may be used instead of the core particle dispersion liquid. That is, a silica sol or a silica-based complex oxide sol can also be obtained by adding an alkaline silicate aqueous solution (or an alkaline silicate aqueous solution and an aqueous solution of a metal salt or non-metal salt other than silicon) described below to such a non-dispersed core particle. be able to. This is because fine particles are generated in the alkaline silicate aqueous solution at the initial stage of adding the aqueous solution,
This is because this acts as a nuclear particle thereafter.

[Liquid II] In the present invention, an aqueous solution of an electrolyte and an aqueous solution of an alkali silicate (in the case of producing a silica-based complex oxide sol, are added to the nuclear particle dispersion (or the non-nuclear particle dispersion, the same applies hereinafter). , An aqueous solution of alkali silicate and an aqueous solution of a metal salt other than silicon or a non-metal salt (the same applies hereinafter)) to grow core particles. The electrolyte aqueous solution may be partially or wholly added to the core particle dispersion in advance, but it is preferably added continuously or intermittently together with the alkali silicate aqueous solution.

Examples of alkali silicates are LiOH and NaO.
Examples thereof include silicic acid alkali salts such as H, KOH, RbOH, CsOH, NH ₄ OH, and quaternary ammonium hydride. Among them, sodium silicate (water glass), potassium silicate and the like can be preferably used. Further, an alkali silicate aqueous solution obtained by hydrolyzing a hydrolyzable organic compound such as tetraethyl orthosilicate (TEOS) with an excess of NaOH or the like is also suitable.

Examples of the metal salt or non-metal salt other than silicon include Al, B, Ti, Zr, Sn, Ce, P, Sb,
Examples thereof include alkali metal salts, alkaline earth metal salts, ammonium salts, and quaternary ammonium salts of oxo acids of elements selected from Mo, Zn, W, and the like, specifically, sodium aluminate, sodium tetraborate. Preferred are ammonium zirconium carbonate, potassium antimonate, potassium stannate, sodium aluminosilicate, sodium molybdate, cerium ammonium nitrate, sodium phosphate, and the like. In the production of the silica-based complex oxide sol, the amount of the alkali silicate aqueous solution and the aqueous solution of the metal salt or non-metal salt other than silicon supplied is the mol when silica is represented by SiO ₂ and the oxide other than silica is represented by MO _X. Ratio (MO _X
/ SiO ₂ ) is preferably in the range of 0.05 to 5, particularly 0.1 to 2. If the molar ratio is less than 0.05, the effect of introducing a component other than silica cannot be obtained, and if the molar ratio exceeds 5, silica particle growth is hindered and unreacted silica and components other than silica increase. Then, the particles may aggregate. When the molar ratio (MO _X / SiO ₂ ) is within the above range, a silica-based composite oxide sol having a uniform particle size distribution and excellent stability can be obtained.

The temperature of the dispersion when adding the alkali silicate aqueous solution is preferably in the range of 40 to 150 ° C, more preferably 60 to 100 ° C. When the temperature is lower than 40 ° C., the reaction rate of silicic acid is slow, the amount of unreacted silicic acid may increase, and particles having a desired size may not be obtained. When the temperature of the dispersion liquid exceeds 150 ° C., there is a problem that the operating pressure becomes too high, the cost of the apparatus becomes high, the production capacity is lowered, and the economical efficiency is lowered. Further, the effect of increasing the reaction rate and the particle growth rate is small in practice.

The addition amount of the aqueous alkali silicate solution can be appropriately selected depending on the particle size of the sol to be obtained. The addition rate of the aqueous alkali silicate solution also varies depending on the temperature of the dispersion, but it can be increased or decreased in proportion to the total external surface area of the core particles in the dispersion, and the addition rate can be adjusted within the range where new fine particles are not formed. You can speed it up. In the present invention, the "addition rate" is expressed by the weight (g) of the SiO ₂ supplied per unit time (m ² ) of the core particles per hour. Here, the "surface area of the core particle" is the external surface area of the sphere calculated by using the average particle diameter by regarding the core particle as a sphere. In the present invention, the supply rate of silica is 0.02 as SiO _2.
05-0.5 g / nuclear particle unit surface area (m ² ) · time, particularly 0.01 to 0.3 g / nuclear particle unit surface area (m ² ) ·
It is preferably in the range of time. In addition, in the production of the silica-based composite oxide sol, when adding an aqueous solution of alkali silicate and an aqueous solution of a metal salt or a non-metal salt other than silicon, “SiO ₂ ” is read as “SiO ₂ + MO _X ”. Further, in the method of the present invention, the addition of the alkali silicate aqueous solution may be intermittent, so the feed rate means the average feed rate. The addition rate is 0.
Below 005 g / nuclear particle unit surface area (m ² ) · hour,
There is no big difference from the method of supplying buildup (particle growth) by supplying an ordinary silicic acid solution, and the effect of increasing the speed cannot be obtained. Moreover, when the addition rate exceeds 0.5 g / nuclear particle unit surface area (m ² ) · time, new fine particles are generated,
The particle size distribution may be wide, non-uniform, and in some cases particles may aggregate.

[Electrolyte] As the electrolyte used in the present invention, a water-soluble salt composed of a conventionally known acid and base can be used. In particular, an electrolyte composed of a salt of a strong acid is preferable because it can accept an alkali of silicic acid alkali, and at this time, generate silicic acid used for grain growth of core particles. Examples of the water-soluble electrolyte composed of such a strong acid salt include sodium salts of strong acids such as sulfuric acid, nitric acid and hydrochloric acid,
Potassium salt, lithium salt, rubidium salt, cesium salt,
Examples thereof include ammonium salt, calcium salt, magnesium salt and the like. Further, alum which is a double salt of sulfuric acid such as potassium alum and ammonium alum is also suitable.

The amount of the above-mentioned electrolyte is the equivalent number (E _A ) of the alkali in the supplied alkali silicate and the equivalent number (E _A ) of the electrolyte.
The ratio of _{E) (E A / E E} ) is 0.5 to 8, particularly 0.5 5
It is preferably in the range of 5. In the production of the silica-based composite oxide sol, when adding a metal salt or a nonmetal salt solution other than alkali silicate aqueous solution and silicon, wherein the "number of equivalents of alkali in the alkali silicate (E _A)" " It should be read as "the total equivalent number (E _A ) of the alkali in the alkali silicate and the alkali or alkaline earth metal in the metal salt other than silicon or the non-metal salt". When the electrolyte ratio (E _A / E _E ) is less than 0.5, the concentration of the electrolyte salt in the dispersion is too high, and the particles may aggregate. When the electrolyte ratio (E _A / E _E ) exceeds 8, the amount of electrolyte is small and the particle growth rate does not increase sufficiently. Therefore, conventional acidic silicic acid solution is supplied to grow core particles. There is no change, and the above-mentioned electrolyte receives the alkali of silicic acid alkali, and the production of silicic acid used for the grain growth of the core particles is reduced, so that particles having a desired grain size may not be obtained. Also, the electrolyte is E _A / E _E
Is in the above range, and the concentration of the electrolyte in the dispersion is preferably in the range of 0.05 to 2% by weight. A part or all of such an electrolyte may be added to the nuclear particle dispersion for use, or may be added continuously or intermittently together with the aqueous alkali silicate solution. The amount of the electrolyte at this time is also preferably in the relation of the ratio of the amount of alkali silicate to the above-mentioned number of equivalents.

If necessary, water may be added to or concentrated in the above dispersion liquid so that the concentration of SiO ₂ (or SiO ₂ + MO _x ) in the dispersion liquid is 0.5 to 10% by weight.
Further, it is preferable to adjust the content to be in the range of 1 to 7% by weight. When the SiO ₂ (or SiO ₂ + MO _X ) concentration is less than 0.5% by weight, the concentration is too low and the production efficiency is low, and concentration may be required before use. On the other hand, when the SiO ₂ (or SiO ₂ + MO _X ) concentration exceeds 10% by weight, the silica particles tend to aggregate, and a sol in which silica particles having a uniform particle size are monodispersed may not be obtained. . While the alkaline silicate aqueous solution is supplied to grow the core particles, it is desirable to maintain the pH of the dispersion liquid in the range of 8 to 13, preferably 10 to 12, while adding an alkali or an acid as needed. As the alkali to be added, sodium hydroxide, potassium hydroxide, lithium hydroxide, aqueous ammonia, or amines such as triethylamine and triethanolamine can be used. Examples of the acid include hydrochloric acid, nitric acid, sulfuric acid, acetic acid, and the like. Organic acids can be used.

[Aging / Deionization] After the above alkaline silicate aqueous solution is added, it is aged if necessary. The aging temperature is in the range of 40 to 150 ° C., preferably 60 to 100 ° C., and the aging time is 10 minutes depending on the aging temperature.
It takes about 3 hours. By performing such aging, it is possible to obtain a silica sol having a more uniform particle size and excellent stability, and a silica-based composite oxide sol.

Next, after cooling the temperature of the dispersion liquid to about 40 ° C. or lower, it is desirable to remove the ions in the dispersion liquid. As a method for removing ions in the dispersion liquid, a conventionally known method can be adopted, for example, an ultrafiltration membrane method,
Examples thereof include an ion exchange resin method and an ion exchange membrane method. For deionization, the amount of remaining anions is preferably 0.01% by weight or less, and more preferably 0.005% by weight or less of SiO ₂ . Residual ion amount is 0.01% by weight
If the amount is below, a silica sol having sufficient stability can be obtained, although it varies depending on the concentration described below, and no adverse effects such as impurities are observed in many applications. The obtained silica sol is concentrated if necessary. As a concentration method, an ultrafiltration membrane method, a distillation method or a method consisting of a combination thereof is usually adopted, and the concentration of the silica sol after concentration is approximately 10 to 50 in terms of SiO ₂ (or SiO ₂ + MO _X ). It is in the range of% by weight. The silica sol is used by appropriately diluting it before use or further concentrating it.

[Organosol] An organosol can be produced by substituting an organic solvent for the dispersion medium of the above water-dispersed silica sol or water-dispersed silica-based composite oxide sol. As a substitution method, a conventionally known method can be adopted, and when the boiling point of the organic solvent is generally higher than that of water, it can be obtained by adding an organic solvent and distilling. When the boiling point of the organic solvent is low, it can be obtained by the ultrafiltration membrane method disclosed in Japanese Patent Application Laid-Open No. 59-8614 filed by the applicant of the present application. The concentration of the obtained organosol is SiO ₂ (or SiO ₂ + MO
It is in the range of 10 to 50% by weight in terms of _X ). Also,
This organosol can be appropriately diluted or further concentrated before use.

[0022]

According to the method of the present invention, silicate, a metal salt other than silicon or a non-metal salt is added in the presence of an electrolyte to grow core particles, whereby a metal or non-metal other than silicate or silicon is added. Even if the supply rate of the salt metal salt is increased, core particles grow without generating new fine particles, and extremely stable monodisperse silica sol and silica-based composite oxide sol can be obtained.

[0023]

EXAMPLES Examples of the present invention will be described below.

[Example 1] Preparation of core particle dispersion liquid (A) Silica sol (manufactured by Catalysts & Chemicals Industry: Cataloid SI-
50, particle diameter 25 nm, SiO ₂ concentration 48% by weight) 9.
6 g of water and 877.9 g of water were mixed, and 32.5 g of a 5% by weight aqueous solution of NaOH was added to adjust the pH of the dispersion to 10.5, and then the temperature of the dispersion was raised to 95 ° C. The core particle dispersion liquid (A) was prepared by maintaining the temperature at 95 ° C. for 30 minutes. Table 1 shows the properties of the nuclear particle dispersion liquid (A). Growth of nuclear particles Next, nuclear particle dispersion liquid (A) in which the temperature was maintained at 95 ° C.
Water glass (manufactured by Dokai Chemical Industry Co., Ltd .: JIS No. 3 water glass, S
iO ₂ concentration 24% by weight) 605.8 g and water 4240.9
19 g of an aqueous solution of alkali silicate obtained by mixing g and 77.5 g of ammonium sulfate (manufactured by Mitsubishi Chemical Corporation) as an electrolyte and 4481.3 g of water.
Added in time. The addition rate at this time is 0.017Si
O ₂ g / nuclear particle unit surface area (m ² ) · hour, the equivalent ratio of alkali to electrolyte E _A / E _E was 1.33. Then, after aging for 1 hour, washing was performed with an ultrafiltration membrane until the pH of the growth nucleus particle dispersion became 10. Then, it was concentrated to obtain a silica sol (A) having a SiO ₂ concentration of 20% by weight. The core particle growth conditions are shown in Table 2, the average particle diameter of the obtained silica sol (A), the standard deviation of the particle diameter, the viscosity and the thermal stability were measured, and the results are shown in Table 3. The thermal stability was evaluated according to the following evaluation criteria by observing the time until gelation of the silica sol in a constant temperature bath at 70 ° C. ◯: stable sol without gelation for 1 week or more x: viscosity increased within 1 week or gelled sol organosol (A) preparation Isopropyl alcohol was added to a part of the silica sol (A). Distillation gave an organosol (A _IPA ) having a SiO ₂ concentration of 20% by weight. An aliquot was taken and replaced with methyl alcohol using an ultrafiltration membrane to obtain an organosol ( _AMOH ). All the sols were stable organosols.

Example 2 A silica sol (B) having a SiO ₂ concentration of 20% by weight was obtained in the same manner as in Example 1 except that the alkaline silicate aqueous solution and the electrolytic aqueous solution were added in 25 hours. The addition rate at this time is 0.013
SiO ₂ g / nuclear particle unit surface area (m ² ) · hour. From the silica sol (B), an organosol (B _IPA ) and an organosol (B _MOH ) were obtained in the same manner as in Example 1. All were stable organosols.

Example 3 A silica sol (C) having a SiO ₂ concentration of 20% by weight was obtained in the same manner as in Example 1 except that the alkali silicate aqueous solution and the electrolyte aqueous solution were added in 8 hours. The addition rate at this time is 0.041S
It was iO ₂ g / unit particle surface area (m ² ) · hour.
From the silica sol (C), an organosol (C _IPA ) and an organosol (C _MOH ) were obtained in the same manner as in Example 1.
All were stable organosols.

Example 4 Preparation of Nuclear Particle Dispersion Liquid (D) The silica sol (A) obtained in Example 1 (particle size 100 nm,
SiO ₂ concentration 20% by weight) 23 g and water 858.5 g are mixed, and 5% by weight concentration of NaOH aqueous solution 18.5 g is mixed with this.
Was added to adjust the pH of the dispersion to 10.5, and then the temperature of the dispersion was raised to 150 ° C. and maintained at 150 ° C. for 30 minutes to prepare a nuclear particle dispersion (D). Growth of nuclear particles Next, nuclear particle dispersion liquid (A) maintained at a temperature of 150 ° C
Water glass (manufactured by Dokai Chemical Industry Co., Ltd .: JIS No. 3 water glass, S
iO ₂ concentration 24% by weight) 605.8 g and water 4240.9
24 g of an aqueous solution of alkali silicate obtained by mixing g and 24 g of an aqueous solution of ammonium sulfate (manufactured by Mitsubishi Chemical Corporation) 77.5 g and water 4481.3 g as an electrolyte.
Added in time. The addition rate at this time is 0.48SiO
₂ g / nuclear particle unit surface area (m ² ) · hour, the equivalent ratio E _A / E _E of alkali to electrolyte was 1.33. Then,
After aging at 150 ° C. for 1 hour, it was washed with an ultrafiltration membrane until the pH of the growth nucleus particle dispersion became 10.
Then, it was concentrated to obtain a silica sol (D) having a SiO ₂ concentration of 20% by weight. Preparation of organosol (D) From the silica sol (D), organosol (D _IPA ) and organosol (D _MOH ) were obtained in the same manner as in Example 1.
All were stable organosols.

[Embodiment 5]Nuclear particle growth A nuclear particle dispersion liquid (A) was prepared in the same manner as in Example 1, and the temperature was adjusted.
To the core particle dispersion (A) whose temperature was maintained at 95 ° C.
(Doikai Chemical Co., Ltd .: JIS No. 3 water glass, SiO ₂concentration
24 wt%) 88.32 g and 271.6 g of water are mixed.
Alkaline silicate aqueous solution obtained with
Solution (Al₂O₃Concentration 22% by weight, Na₂O concentration 17-fold
%) 27.2 g and 514.4 g of water
Aqueous sodium luminate solution and ammonium sulfate as electrolyte
Nitrogen (manufactured by Mitsubishi Chemical Corporation) 11.4 g and water 286.8
and the aqueous electrolyte solution obtained by mixing
It was The addition rate at this time was 0.006 (SiO 2₂+ A
l₂O₃) G / nuclear particle unit surface area (m²) ・ Time, Al
Potassium (alkali silicate and sodium aluminate alkali
And the equivalent ratio E of the electrolyte and E_A/ E_EIs 2.18
It was Then, after aging for 1 hour, using an ultrafiltration membrane
Wash until the pH of the growth nucleus particle dispersion becomes 10.
It was Then, concentrate (SiO 2₂+ Al₂O₃) Concentration
20 wt% silica sol (E) was obtained.Preparation of organosol (E) From the silica sol (E), the same procedure as in Example 1 was conducted.
Ganosol (E_IPA), Organosol (E_MOH) Got.
All were stable organosols.

[Example 6] Growth of nuclear particles Water glass (manufactured by Dokai Chemical Industry Co., Ltd .: JIS No. 3 water glass, SiO)
₍₂ concentration 24% by weight) 0.5 g of water and 899.5 g of water were mixed to obtain an alkali silicate aqueous solution, and the temperature was raised to 95 ° C., and water glass (manufactured by Dokai Kagaku Co., Ltd .: JIS No. 3 water glass) , S
iO ₂ concentration 24% by weight) 605.8 g and water 4240.9
19 g of an aqueous solution of alkali silicate obtained by mixing g and 77.5 g of ammonium sulfate (manufactured by Mitsubishi Chemical Corporation) as an electrolyte and 4481.3 g of water.
Added in time. In this example, 30 minutes after the start of the addition of the aqueous electrolyte solution or the like, the addition was temporarily stopped for 30 minutes to self-generate core particles and make the particle diameter uniform.
The average particle size of the obtained core particles was 3 nm. At this time, the addition rate was 0.036 SiO ₂ g / nuclear particle unit surface area (m ² ) · hour, the equivalence ratio E _A of alkali and electrolyte /
E _E was 1.33. Then, after aging for 1 hour, washing was performed with an ultrafiltration membrane until the pH of the growth nucleus particle dispersion became 10. Then, it was concentrated to obtain a silica sol (F) having a SiO ₂ concentration of 20% by weight. Preparation of Organosol (F) From the above silica sol (F), organosol (F _IPA ) and organosol (F _MOH ) were obtained in the same manner as in Example 1.
All were stable organosols.

Example 7 A nuclear particle dispersion (A) was prepared in the same manner as in Example 1, and then 77.3 g of ammonium sulfate was used as an electrolyte instead of 73.3 g of sodium sulfate.
A SiO ₂ concentration of 2 was obtained in the same manner as in Example 1 except that g was used.
0 wt% silica sol (G) was obtained. From the silica sol (G), the organosol (G
_IPA ) and organosol (G _MOH ) were obtained. All were stable organosols.

[Example 8] A nuclear particle dispersion (A) was prepared in the same manner as in Example 1, and then, as in Example 1, except that 38.8 g of ammonium sulfate and 4519 g of water were used as electrolytes. A silica sol (H) having a SiO ₂ concentration of 20% by weight was obtained. Example 1 from the above silica sol (H)
In the same manner as described above, organosol (H _IPA ) and organosol (H _MOH ) were obtained. All were stable organosols.

[Comparative Example 1] In Example 1, ammonium sulfate (produced by Mitsubishi Chemical Corporation) 77.5 as an electrolyte was used.
Silica sol (I) was obtained in the same manner as in Example 1 except that 77.5 g of water was used instead of g (that is, without using an electrolyte), and an aqueous alkali silicate solution and water were added over 19 hours. From the above silica sol (I), organosols (I _IPA) in the same manner as in Example 1 to obtain an organosol (I _MOH). All were stable organosols.

Comparative Example 2 Growth of Nuclear Particles The temperature of the nuclear particle dispersion liquid (A) prepared in the same manner as in Example 1 was maintained at 95 ° C., and water glass (JIS No. 3 water glass, SiO ₂ concentration) was added thereto. Acidified silicic acid solution (pH 2.2, SiO ₂ concentration 5% by weight) obtained by dealkalizing 5% by weight) 2900
g was added in 95 hours. The addition rate at this time is 0.0
03 SiO ₂ g / nuclear particle unit surface area (m ² ) · hour. Then, after aging for 1 hour, washing was performed with an ultrafiltration membrane until the pH of the growth nucleus particle dispersion became 10. Then, it was concentrated to obtain a silica sol (J) having a SiO ₂ concentration of 20% by weight. Preparation of organosol (J) From the above silica sol (J), organosol (J _IPA ) and organosol (J _MOH ) were obtained in the same manner as in Example 1.
All were stable organosols.

[0034]

TABLE 1 I liquid electrolytic electrolyte core particles having an average particle diameter pH type equivalent ratio (nm) (* 1) E A / E E Example 1 Yes 25 10.5 Ammonium sulfate 1.33 Example 2 Yes 25 10.5 Ammonium sulfate 1.33 Example 3 Yes 25 10.5 Ammonium sulphate 1.33 Example 4 Yes 100 10.5 Ammonium sulphate 1.33 Example 5 Yes 25 10.5 Ammonium sulphate 2.18 Example 6 No 3 9.8 Ammonium sulphate 1.33 Example 7 Yes 25 10.5 Na sulphate 1.33 Example 8 Yes 25 10.5 Ammonium sulphate 0.67 Comparative Example 1 Yes 25 10.5 − − Comparative Example 2 Yes 25 10.5 − − (* 1) Ammonium sulfate: ammonium sulfate, sulfur sulfate: sodium sulfate

[0035]

[Table 2] Liquid II (* 2) added condition Aged silicic acid and other MO _X addition rate Concentration pH Temperature Time Alkali metal salt / SiO ₂ (g / m ² · hr) (wt%) (℃) (hr ) Example 1 W-0 0.017 1.5 11.5 95 1 Example 2 W-0 0.013 1.5 11.5 95 1 Example 3 W-0 0.041 1.5 11.5 95 1 Example 4 W-0 0.480 1.5 11.5 150 1 Example 5 W NaAl 0.33 0.006 1.5 11.7 95 1 Example 6 W-0 0.036 1.5 11.5 95 1 Example 7 W-0 0.017 1.5 11.7 95 1 Example 8 W-0 0.017 1.5 11.6 95 1 Comparative Example 1 W-0 0.017 1.5 12.0 95 1 Comparative Example 2 A-0 0.003 3.9 10.1 95 1 (* 2) W: water glass, A: acidic silicic acid solution, NaAl: sodium aluminate

[0036]

[Table 3]

Continued front page    (72) Inventor Naoyuki Enomoto             13-2 Kitaminato-cho, Wakamatsu-ku, Kitakyushu, Fukuoka             Kasei Industry Co., Ltd. Wakamatsu factory F term (reference) 4G072 AA28 CC01 CC02 EE01 EE07                       GG01 GG02 HH02 HH18 HH24                       JJ13 JJ30 MM01 PP01 PP02                       RR12                 4G073 BA57 BD06 CE01 FB28 FD14

Claims (6)

[Claims] 1. A method for producing a silica sol or a silica-based complex oxide sol, which comprises adding a solution II to the following solution I in the presence of an electrolyte to grow core particles. Solution I: Nuclear particle dispersion or alkaline silicate aqueous solution II: Alkali silicate aqueous solution or alkaline silicate aqueous solution and metal salt or non-metal salt aqueous solution other than silicon 2. The electrolyte comprises a salt of a strong acid, and the ratio (E _A / E) of the equivalent number (E _A ) of alkali in the supplied alkali silicate and the equivalent number (E _E ) of the electrolyte.
_The method for producing a silica sol or a silica-based composite oxide sol according to claim 1, wherein _E ) is in the range of 0.5 to 8. 3. After adding the liquid II, 40 to 150 ° C.
The method for producing a silica sol or a silica-based complex oxide sol according to claim 1 or 2, wherein the mixed solution is aged in the temperature range of 10 minutes to 3 hours. 4. The mixture is deionized so that the amount of residual anions is 0.01% by weight or less of SiO ₂ .
The method for producing the silica sol or the silica-based composite oxide sol according to claim 3. 5. A silica sol or a silica-based complex oxide sol obtained by the method according to any one of claims 1 to 4 is used as the core particle dispersion liquid.
8. A method for producing the silica sol or the silica-based composite oxide sol according to any one of 1. 6. A method for producing an organosol, wherein the silica sol or the silica-based complex oxide sol obtained by the method according to claim 1 is replaced with an organic solvent.