KR101050549B1 - Preparation method of silica sol and silica sol - Google Patents

Abstract

The seed particles are rapidly grown by adding active silica particles having a predetermined size to the seed particle dispersion.

The method for producing a silica sol comprising adding the active silicate particle dispersion liquid of the following (b) to the seed particle dispersion of the following (a) continuously or intermittently while heating, and attaching the active silicate particle to the seed particle to grow the particles. .

(a) An aqueous dispersion of seed particles having an average particle diameter (D _LS ) measured in the range of 5 to 1000 nm as measured by dynamic light scattering by a laser beam, the seed particle dispersion having a pH of 7 to 12

(b) the average particle diameter (D _LF ) measured by the dynamic light scattering method by laser light is in the range of 2 to 50 nm, provided that the average particle diameter (D _LF ) is smaller than the average particle diameter (D _LS ); Moreover, the average particle diameter (D _NaF ) measured by NaOH titration method is in the range of 0.9 to 6 nm, and moreover, the ratio of the average particle diameter (D _LF ) and the average particle diameter (D _NaF ) (D _LF ) / (D An aqueous silicate dispersion of active silicate particles having _NaF ) in the range of 1.8 to 30, wherein the active silicate particle dispersion having a pH in the range of 5 to 11.

Description

Silica sol manufacturing method and silica sol {Method of Manufacturing of Silica Sol and Silica Sol}

TECHNICAL FIELD This invention relates to the manufacturing method of the silica sol using a seed particle dispersion, and the silica sol obtained by this manufacturing method.

Conventionally, many proposals are made about the method of manufacturing a silica sol. Among them, in the method of adding an acidic silicate solution obtained by de-alkali alkali metal silicate to the seed particle dispersion, the particle diameter of the silica colloidal particles obtained is uniform and can be adjusted to the desired particle size. For example, the inventors of the present application prepare seed particles in Japanese Patent Application Laid-Open No. 63-45114 (Patent Document 1), and remove an alkali metal silicate aqueous solution such as water glass into an ion exchange resin or the like. A method of producing silica sol by adding an acidic silicic acid solution obtained by alkali, bonding, stacking and depositing acidic silicic acid on the seed particle surface to grow the seed particles.

However, in the method of adding an acidic silicic acid solution to such a seed particle dispersion, (1) the polymerization degree of the acidic silicic acid is low at about 1 to 4, so that it takes a long time to grow the particles, and in particular, silica particles having a uniform and large particle diameter are produced. In order to obtain the silica sol containing, it was necessary to repeat particle growth. In addition, (2) the particle surface area decreases with the growth of the particles, so that, for example, it is necessary to reduce the addition rate of the acidic silicic acid solution. When the addition speed of the liquid was increased, the particles were agglomerated, new fine particles were generated, and the particle diameter distribution of the obtained silica sol was uneven. In addition, (3) the acidic silicic acid solution has low stability, and thus has a problem such as a very strict condition for process control.

[Patent Document 1]

Japanese Patent Laid-Open No. 63-45114

The present invention is to provide a method for producing a silica sol capable of rapidly growing a seed particle by adding a dispersion containing active silica particles having a predetermined size to the seed particle dispersion.

Moreover, an object of this invention is to provide the silica sol obtained by the said manufacturing method.

In the method for producing a silica sol according to the present invention, the active silicate particle dispersion of the following (b) is continuously or intermittently added to the seed particle dispersion of the following (a) while heating to attach active silica particles to the seed particle, It is characterized by growing the particles.                         

(a) The seed particle dispersion liquid whose pH was in the range of 7-12 as an aqueous acid solution of the seed particle whose average particle diameter (D _LS ) measured by the dynamic light scattering method by a laser beam is 5-1000 nm.

(b) the average particle diameter (D _LF ) measured by the dynamic light scattering method by laser light is in the range of 2 to 50 nm, provided that the average particle diameter (D _LF ) is smaller than the average particle diameter (D _LS ); Furthermore, the average particle diameter (D _NaF ) measured by NaOH titration method is in the range of 0.9 to 6 nm, and further, the ratio of the average particle diameter (D _LF ) and the average particle diameter (D _NaF ) (D _LF ) / ( D _NaF ), which is an aqueous acid solution of active silica particles in the range of 1.8 to 30, wherein the active silica particle dispersion has a pH in the range of 5 to 11.

In this manufacturing method, it is preferable to perform said heating in the temperature range of 60-160 degreeC.

Activated silica particles obtained by neutralizing silica hydrogel produced by (a) neutralizing alkali silicate with acid with alkali, or (b) silica hydrogel produced by neutralizing alkali silicate with acid It is preferable that it is an active silicate particle obtained by making it refine | miniaturize mechanically, bridge | crosslinking with alkali.

In addition, the average particle diameter (D _LF) of the active silicic acid particles is not more than the mean particle size (D _LS) of the seed particles is 12nm, is less than or equal to 7/10 of the mean particle size (D _LS), the species When the average particle diameter D _{LS of the} particles exceeds 12 nm, the average particle diameter D _LS is preferably 5/10 or less of the average particle diameter D _LS .

In the silica sol according to the present invention, the average particle diameter (D _LZ ) measured by the dynamic light scattering method by laser light is in the range of 12 to 200 nm, and the average particle diameter (D _NaZ ) measured by the NaOH titration _method is 5 to in the range of 30nm, and further characterized in that the mean particle size (D _LZ) and the ratio _{(D LZ) / (D NaZ} ) with the mean particle size (D _NaZ) is within the range from 2 to 30.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated concretely.

[Seed particle dispersion]

The seed particle dispersion of the present invention is an aqueous acid solution of seed particles having an average particle diameter (D _LS ) measured in a dynamic light scattering method using a laser beam, in the range of 5 nm to 1000 nm, wherein the pH is in the range of 7 to 12. Used.

As seed particles of the seed particle dispersion used in the present invention, inorganic oxides such as SiO ₂ , Al ₂ O ₃ , TiO ₂ , ZrO ₂ , or fine particles of these composite oxides are used, but among them, SiO ₂ is preferable. . This seed particle is usually used in the state of an aqueous sol dispersed in water.

In addition, other conventionally known seed particle dispersions may be used, and for example, the seed liquid disclosed in the above-mentioned Patent Publication No. 63-45114 may be preferably used. Specifically, an alkali silicate aqueous solution and / or an alkaline aqueous solution and an acidic silicic acid solution are mixed to adjust the SiO ₂ / M ₂ O (M: alkali metal) molar ratio of the mixed solution to 2.8 to 10, followed by a temperature of 60 ° C. or higher. By aging with a seed solution (seed particle dispersion) can be obtained.

The particle size of the seed particles may be appropriately selected and used in consideration of the silica particle diameter of the silica sol to be finally obtained, but the particle used in the silica sol production method according to the present invention has a high particle growth rate. The particle does not necessarily need to prepare the seed particle which enlarged in advance in time, and can use the seed particle of small particle diameter in the range which functions as a seed particle.

The average particle diameter of such seed particles is approximately 5 to 1000 nm, preferably 7 to 100 nm, as measured by the dynamic light scattering method using a laser beam. When the average particle diameter is less than 5 nm, the seed particles may be unstable and may gel or aggregate when the active silicate particle dispersion is added. In addition, when the average particle diameter exceeds 1000 nm, it usually takes time for preparation of the seed particles, which is not suitable for the well-known art of improving the productivity by growing the seed particles quickly.

Although there is no restriction | limiting in particular in the density | concentration of a seed particle dispersion liquid, Usually, the range of 0.1-20 weight%, Preferably it is 0.5-10 weight% in conversion of oxide. When this value is less than 0.1 weight% in oxide conversion, since concentration is low, it may melt | dissolve easily and particle | grains may reduce or disappear, and it may not show a function as a seed particle. When the concentration of the seed particle dispersion exceeds 20% by weight in terms of oxide, the seed particles may agglomerate, whereby a monodisperse sol having a uniform particle diameter may not be obtained. In addition, since the concentration of seed particles is high, it is necessary to slow down the feed rate of the active silicate particle dispersion and prevent aggregation and the like. Furthermore, because of the large number of seed particles, the growth rate of each particle can be suppressed, and rapid grain growth may be hindered.

The pH of the seed particle dispersion is usually in the range of 7 to 12, and more preferably in the range of 8 to 11. If the pH is less than 7, the potential of the particle surface is lowered and the particles may aggregate, and if the pH exceeds 12, the seed particles may dissolve or the activated silica particles to be added may dissolve, resulting in slow particle growth. The particle diameter distribution may become uneven.

From 2.8 to 200 (for an alkali metal M) molar ratio, seed particle dispersion is, NaOH, KOH, etc. or an aqueous solution of an alkali metal aqueous solution such as is preferred, seed particles SiO ₂ / M ₂ O in the dispersion liquid was added as needed, It is especially preferable to set it as the range of 2.8-120. When the SiO ₂ / M ₂ O molar ratio is less than 2.8, the seed particles may be dissolved. On the other hand, when the SiO ₂ / M ₂ O molar ratio exceeds 200, when the active silicate particle dispersion is supplied to the seed particle dispersion. The pH of a dispersion falls and particle | grains may aggregate.

[Active silicate particle dispersion]

As the active silica particle dispersion of the present invention, the average particle diameter (D _LF ) measured by the dynamic light scattering method by laser light is in the range of 2 to 50 nm (wherein the average particle diameter (D _LF ) is the average particle diameter (D _LS )). Smaller), and furthermore, the average particle diameter (D _NaF ) measured by NaOH titration method is in the range of 0.9 to 6 nm, and furthermore, the ratio of the average particle diameter (D _LF ) to the average particle diameter (D _NaF ) As the aqueous acid solution of the active silica particles in which D _LF ) / (D _NaF ) is in the range of 1.8 to 30, those having a pH in the range of 5 to 11 are used.

The active silica particles used in the present invention are required to be within a predetermined particle size range from the necessity of contributing to the rapid grain growth of seed particles. In addition, in order for the active silica particles to adhere to the seed particles and grow particles, the average particle diameter of the active silica particles is required to be smaller than that of the seed particles. As the active silicate particles used in the present invention, porous activated silica particles are used. The method for producing such active silica particles is not particularly limited, and examples thereof include active silica particles prepared by using silica hydrogel as a raw material. In addition, since the active silicate particles used in the present invention are porous, not only the measured values by the dynamic light scattering method by laser light but also the measured values by the NaOH titration method are required as a method for defining the average particle diameter.

Hereinafter, these are explained in full detail.

When an active silica particle dispersion having an average particle diameter (D _LF ) of active silica particles of less than 2 nm is added to the seed particle dispersion, the particle growth rate of the seed particles is slow, and the active silica particle dispersion is similar to the acid silicate solution. It is unstable, and it is difficult to make it high concentration. When a low concentration of active silicate dispersion is added to the seed particle dispersion, the seed particle concentration in the dispersion is also lowered, resulting in a decrease in production efficiency.

On the other hand, if the average particle diameter (D _LF ) of the active silica particles exceeds 50 nm, it hardly contributes to the grain growth of the seed particles. Therefore, it is preferable that this average particle diameter D _LF exists in the range of 3-40 nm.

The particle diameter by the dynamic light scattering method by a laser beam can be measured, for example by a particle size distribution measuring apparatus (NICOMP-380 by Particle Sizing Systems), and a visual measurement value can be obtained.

In addition, a more in order to obtain a rapid particle growth rate, the average particle size of the active silicic acid particles (D _LF) is, when the average particle diameter (D _LS) of the seed particles less than 12nm, the average particle diameter (D _LS) When it is 7/10 or less and the average particle diameter D _LS of the said seed particle exceeds 12 nm, it is preferable that it is 5/10 or less of the said average particle diameter D _LS .

Further, the active silica particles have an average particle diameter (D _NaF ) measured by NaOH titration method in the range of 0.9 to 6 nm, and furthermore, the ratio of the average particle diameter (D _LF ) to the average particle diameter (D _NaF ) ( It is required that D _LF ) / (D _NaF ) be in the range of 1.8 to 30.

When the average particle diameter (D _NaF ) is less than 0.9 nm, the growth rate of the seed particles is slow as in the case of using a conventional acidic silicate solution, and the stability of the active silicate particle dispersion is insufficient, so that the active silicate particle dispersion is We cannot do it at high concentration and cannot expect improvement of productivity. When the average particle diameter (D _NaF ) exceeds 6 nm, the particle diameter of the silica particles finally obtained by generating new particles without selectively depositing them on the surface of the seed particles, depending on the particle size of the seed particles. The distribution tends to be nonuniform.

In addition, when the ratio (D _LF ) / (D _NaF ) of the average particle diameter of the active silica particles measured using the dynamic light scattering method by laser light and the average particle diameter of the same particles measured using the NaOH titration method is less than 1.8. Also, depending on the size of the average particle diameter (D _LF ), the reactivity of the active silica particles is low, the effect of increasing the particle growth rate is insufficient. On the other hand, when the ratio (D _LF ) / (D _NaF ) of the above average particle diameter exceeds 30, the particle strength of the silica particles obtained is weakened, for example, when used as an abrasive, such as a semiconductor substrate, as abrasive particles. In some cases, sufficient polishing speed may not be obtained.

The particle diameter by NaOH titration method can be calculated | required by measuring the specific surface area (SA _Na ) of active silicic acid computed by the Sears method, and calculating by following formula (1).

D _Na = 6000 / (2.2 × SA _Na ) ... (1)

In formula (1), the constant 2.2 is the specific gravity of silica. In the measurement by the NaOH titration method, when the particles are not porous, they are almost the same as the measured values by the laser beam, but when the particles are porous, the particle diameter is apparently small.

Porous active silica particles are considered to have high reactivity with seed particles and adhere to the seed particles, causing active particle growth.                     

As said active silicate particle dispersion, the thing of pH range 5-11 is mainly used for the synthetic reason. In addition, when it is out of this range, it becomes difficult to obtain sufficient particle growth rate.

[Preparation of Active Silicate Particle Dispersion]

The above-mentioned active silicate particles can be produced by various methods, but are obtained by mechanically miniaturization while (a) peptizing silica hydrogel with alkali or (b) peptizing silica hydrogel with alkali. Silicate particles are preferred as the active silicate particles of the present invention. Moreover, you may mix and use the active silicate particle obtained by the method of said (a) and (b).

As the silica hydrogel, a silica hydrogel produced by neutralizing alkali silicate with an acid is preferable. At this time, as alkali silicate, alkali metal silicates such as sodium silicate and potassium silicate are used, and it can be obtained by adding an acid such as hydrochloric acid, nitric acid, sulfuric acid, etc. to this aqueous solution.

The concentration of the alkali metal silicate solution at the time of neutralization, a SiO ₂ 1~10% by weight, more 2-8% by weight, the temperature is room temperature (usually 15~35 ℃), pH after neutralization is in the range of 3 to 7 It is preferable. When this concentration is less than 1% by weight as SiO ₂ , polymerization (gelling) of silicic acid is insufficient, the particle size (D _LF ) of the active silicic acid particles obtained becomes small, and the particle growth rate may be insufficient. On the other hand, when this concentration exceeds 10% by weight as SiO ₂ , it cannot be uniformly neutralized and the polymerization of silicic acid becomes nonuniform, and the particle diameter (D _LF ) distribution of the active silicate particles obtained tends to be nonuniform.

It is preferable to wash and use the silica hydrogel obtained by neutralizing in this way as needed.

As a 1st manufacturing method of an active silicate particle dispersion, the method of adding an alkali to the dispersion liquid of a silica hydrogel, and peptizing a silica hydrogel is mentioned. At this time, the concentration of the silica hydrogel dispersion, as SiO ₂ is preferably in the range of 0.5 to 5% by weight, more 1-4% by weight. When this concentration is less than 0.5% by weight, the proportion of silica dissolved is increased, and the average particle diameter (D _LF ) of the active silica particles obtained is small, making it difficult to obtain an effect of accelerating the particle growth rate. In addition, when this concentration exceeds 5% by weight as SiO ₂ , the average particle diameter (D _LF ) of the active silica particles obtained may exceed 50 nm or become nonuniform, and depending on the size of the seed particles, Particle diameter distribution may become nonuniform.

As an alkali, alkali metal hydroxides, such as KOH and NaOH, ammonium hydroxide, an amine aqueous solution, etc. can be used. The amount of the alkali is, the number of moles (M _A) with a non _{(M S) / (M A} ) of number of moles of SiO ₂ in the silica hydrogel dispersions (M _S) and alkali (expressed as M ₂ O) 5~100, It is preferable to use so that it may become the range of 10-50 further. When the molar ratio (M _S ) / (M _A ) is less than 5, the average particle diameter (D _NaF ) measured by the NaOH titration method tends to be less than 0.9 nm, and the proportion of dissolved silica increases, and thus the silica sol Production efficiency or yield is lowered. On the other hand, when the molar ratio (M _S ) / (M _A ) exceeds 100, peptising is insufficient, and the average particle diameter (D _NaF ) exceeds 6 nm, resulting in deactivation of the active silicate particle dispersion. The active silica particles used for growing the particles are reduced, resulting in uneven particle diameter distribution of the resulting silica sol. The pH at the time of peptizing has the preferable range of 5-11. When pH is less than 5, since a dispersion liquid becomes high viscosity, it becomes difficult to obtain stable active silicate particle. When the pH exceeds 11, the silica is easily dissolved and becomes unstable.

It is preferable that the temperature at the time of peptizing the said silica hydrogel with alkali is in the range of 50-150 degreeC, and also 60-95 degreeC. In the case of less than 50 degreeC, sufficient uniform peptization may not be possible. When the temperature exceeds 150 ° C, the average particle diameter (D _NaF ) also exceeds 10 nm, and the particle diameter distribution of the resulting silica sol tends to be nonuniform.

As a 2nd manufacturing method of an active silicate particle dispersion, the method of mechanically refine | miniaturizing, peptizing silica hydrogel with alkali is mentioned. Micronization is performed by treating with a grinder, such as a sand mill and a ball mill, for about 10 minutes-several hours, adding alkali to the dispersion liquid of a silica hydrogel, and peptizing.

[Production of Silicazol]

In the silica sol production method according to the present invention, the active silicate particle dispersion is added to the seed particle dispersion continuously or intermittently while heating. It is preferable that the temperature of the seed particle dispersion liquid in this case exists in the range of 60-160 degreeC, and further 70-120 degreeC. If the temperature is less than 60 ° C., since the precipitation rate of the active silica particles on the surface of the seed particles is slow, it is necessary to slow down the addition rate of the active silica particle dispersion, resulting in inhibiting the rapid growth of the seed particles. There is a case. Moreover, when this temperature exceeds 160 degreeC, there exists a tendency for the melt | dissolution amount of the silica which is a seed particle to increase, and agglomerated particles generate | occur | produce, or the yield of a silica sol falls. On the other hand, when the active silicate particle dispersion is added to the seed particle dispersion, it is usually preferable to stir slowly. In addition, you may perform this operation using an autoclave as needed.

The active silicate particle dispersion to be added may be added to the active silicate particle dispersion having a concentration of approximately 0.5 to 5% by weight as SiO ₂ obtained by the above method as it is, but may be diluted or concentrated if necessary. In this case, the concentration of the active silicate particle dispersion at the time of addition is preferably in the range of 0.5 to 10% by weight and more preferably 1 to 8% by weight as SiO ₂ . When this concentration is less than 0.5% by weight, the concentration of the seed particle dispersion decreases with the addition of the active silicate particle dispersion, the solubility of the silica increases when the particle grows under heating, the dispersion becomes unstable and the particles aggregate, Yield may fall. On the other hand, when this concentration exceeds 10% by weight, depending on the rate of addition of the active silicate particle dispersion, new fine particles may be generated and a silica sol having a uniform particle size distribution may not be obtained.

The ratio of adding the active silicate particle dispersion to the seed particle dispersion depends on the concentration of the seed particles in the seed particle dispersion, the particle diameter of the seed particles, the degree of polymerization of the active silica particles, the temperature of the seed particle dispersion, and the like. It is preferable to adjust so that the growth rate of a diameter may be in the range of 0.5 to 5 nm / hour, and further 1 to 4 nm / hour. As an addition ratio of the active silicate particle dispersion liquid such that the particle diameter growth rate of the seed particles is less than 0.5 nm / hour, there is no significant difference from the conventional method for producing silica sol by acidic silicate solution, and the effect of speeding up the particle growth rate Is not exerted enough. In addition, the addition of the active silicate particle dispersion in which the particle diameter growth rate of the seed particles exceeds 5 nm / hour is too fast, so that the active silicate particles generate new fine particles, thereby obtaining a uniform particle size distribution of silica sol. There may be no.

After the addition of the active silicate particle dispersion is completed, aging can be carried out as necessary. When aging, a silica sol having a more uniform particle size can be obtained.

As described above, the silica sol obtained by the method for producing a silica sol according to the present invention has an average particle diameter D _LZ of 12 to 200 nm, preferably 15 to 180 nm, as measured by dynamic light scattering method using a laser beam. The average particle diameter (D _NaZ ) measured by the NaOH titration method is in the range of 5 to 30 nm, preferably 5 to 20 nm.

The ratio (D _LZ ) / (D _NaZ ) of the average particle diameter is in the range of 2 to 30, preferably 2 to 20. When said ratio (D _LZ ) / (D _NaZ ) is less than 2, it may require long-term aging or aging at high temperature, and the rapid particle growth effect in this invention cancels out. On the other hand, when the ratio (D _LZ ) / (D _NaZ ) exceeds 30, the particle strength of the silica particles is insufficient, and, for example, when the abrasive particles are used in abrasive materials such as semiconductor substrates, a desired polishing rate can be obtained. You may not be able to.

The silica sol of this invention can be used as it concentrates or dilutes as needed. As the concentration method, there are a method of heating and evaporating water, a method of using an ultrafiltration membrane, and the like. At this time, the concentration of silica sol as SiO ₂ is usually adjusted in the range of 10 to 50% by weight.

In addition, the silica sol of this invention can also be made into an organosol by carrying out solvent substitution with an organic solvent as needed. As an organic solvent which can be used for this solvent substitution, Alcohol, such as methanol, ethanol, propanol, butanol, diacetone alcohol, furfural alcohol, tetrahydrofurfural alcohol, ethylene glycol, hexylene glycol; Esters such as methyl acetate and ethyl acetate; Ethers such as diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether and diethylene glycol monoethyl ether; Ketones, such as acetone, methyl ethyl ketone, acetyl acetone, and aceto acetate ester, amides, such as N-methylpyrrolidone, dimethylformamide, etc. are mentioned. These may be used independently, and may mix and use 2 or more types.

In addition, the silica sol of this invention may be surface-treated with a silane coupling agent, and may give hydrophobicity, and may remove and use alkali in a silica sol by ion-exchange resin etc. as needed.                     

Example 1

Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. In the following Examples and Comparative Examples, for the seed particles, the active silica particles and the silica sol, the average particle diameter was measured using a dynamic light scattering method using a laser beam (a particle diameter distribution measuring apparatus manufactured by Particle Sizing System: NICOMP model 380], and the results are shown in Table 1. In addition, in the active silica particles and the silica sol, the average particle diameter measurement calculated from the specific surface area calculated by the NaOH titration method (Sears method) was also performed, and the results are shown in Table 1 as well.

Table 1 also shows the pH values of the seed particle dispersions and the active silica particle dispersions used in the following Examples and Comparative Examples, and the ratio of the average particle diameter (D _LF ) and the average particle diameter (D _NaF ) of the active silica particles. The value of (D _LF ) / (D _NaF ) and the ratio of the average particle diameter (D _LF ) of the active silica particles to the average particle diameter (D _LS ) of the seed particles (D _LF ) / (D _LS ) Values are also shown.

Preparation of Acidic Silicate

Of the concentration as a SiO ₂ 24% by weight sodium silicate aqueous solution (SiO ₂ / Na ₂ O molar ratio of 3.1) was diluted with ion-exchanged water, the concentration of SiO ₂ as to prepare a dilute aqueous solution of sodium silicate, 5.2% by weight. The acidic silicic acid solution was prepared through the column which filled this solution with the hydrogen type ion exchange resin (made by Mitsubishi Chemical Corporation: Diaion SK-1B). The SiO ₂ concentration of the acidic silicate solution was 5.O wt% and the pH was 2.7. In addition, the average particle diameter measured by the dynamic light scattering method by a laser beam was 1 nm.

Preparation of seed particle dispersion (1)

Reflux group was diluted in a stainless steel vessel of a stirrer, a 30L with a temperature sensing device, the a sodium silicate aqueous solution has a concentration as a SiO ₂ 24% by weight of (SiO ₂ / Na ₂ O molar ratio of 3.1) 163g with ion exchange water 2760g . 4420 g of the acidic silicic acid solution prepared separately was mixed with this liquid, and then heated at 60 ° C. for 30 minutes to prepare a seed particle dispersion 1 having a concentration of 4.6 wt% as SiO ₂ . The mean particle size of the seed particles measured by a dynamic light scattering method with the laser light (D _LS) is 5nm, SiO ₂ / Na ₂ O molar ratio was 20.

Preparation of Active Silicate Particle Dispersion (1)

Of the concentration as a SiO ₂ 24% by weight sodium silicate aqueous solution (SiO ₂ / Na ₂ O molar ratio of 3.1) was diluted with ion-exchanged water, the concentration of SiO ₂ as to prepare a dilute aqueous solution of sodium silicate, 5.2% by weight. Sulfuric acid was added to this aqueous sodium silicate solution and neutralized to prepare a silica hydrogel. After sufficiently washing the silica hydrogel with water, 43 kg of a silica hydrogel dispersion having a concentration of 5% by weight of SiO ₂ was added thereto, and 955 g of a 20% by weight aqueous NaOH solution was added thereto, and the solution was peptized at 80 ° C. for 3 hours. A silicate particle dispersion (1) was prepared. SiO ₂ concentration in this case is 3% by weight, the number of moles of SiO ₂ (M _S) and alkali (expressed as M ₂ O) molar number ratio _(S M) / (M _A) with _(A M) of was 15. In addition, the average particle diameter (D _LF ) measured by the dynamic light scattering method by a laser beam was 3 nm, and the average particle diameter (D _NaF ) measured by the NaOH titration method was 1 nm.

Preparation of Silica Sol (1)

To 410 g of the seed particle dispersion (1) prepared at a temperature of 80 ° C, 42716 g of the active silicate particle dispersion (1) was added for 11 hours to prepare a silica sol (1). Table 1 shows the SiO ₂ concentration of silica sol, average particle diameter (D _LZ ) measured by dynamic light scattering method by laser light, average particle diameter (D _Na ) and particle growth rate measured by NaOH titration method. On the other hand, in calculating the particle growth rate, the measured value of the average particle diameter (D _LZ ) measured by the dynamic light scattering method using a laser beam was used.

[Example 2]

Preparation of seed particle dispersion (2)

Reflux group was diluted in a stainless steel vessel of a stirrer, a 30L with a temperature sensing device, the a sodium silicate aqueous solution has a concentration as a SiO ₂ 24% by weight of (SiO ₂ / Na ₂ O molar ratio of 3.1) 163g with ion exchange water 2760g . 18200 g of the acidic silicic acid solution prepared in the same manner as in Example 1 was mixed, and then heated at 80 ° C. for 30 minutes to prepare a seed particle dispersion _{2 having} a concentration of 4.6 wt% as SiO ₂ . The average particle diameter measured by a dynamic light scattering method with the laser light (D _LS) is 12nm, SiO ₂ / Na ₂ O molar ratio was 70.

Preparation of Active Silicate Particle Dispersion (2)

The active silicate particle dispersion 2 was prepared in the same manner except that only 480 g of NaOH aqueous solution having a concentration of 20% by weight was prepared according to the method for producing the active silicate particle dispersion 1. SiO ₂ concentration at this time was 3% by weight, the number of moles of SiO ₂ (M _S) and alkali (expressed as M ₂ O) molar number _(A M) ratio _{(M S) / (M A} ) of between 30. In addition, the average particle diameter (D _LF ) measured by the dynamic light scattering method by a laser beam was 6 nm, and the average particle diameter (D _NaF ) measured by the NaOH titration method was 2 nm.

Preparation of Silica Sol (2)

To 410 g of the seed particle dispersion (2) prepared at a temperature of 80 ° C, 24556 g of the active silicate particle dispersion (2) was added for 15 hours to prepare a silica sol (2). As in Example 1, SiO ₂ concentration, average particle diameter, and particle growth rate of the silica sol are shown in Table 1.

Example 3

Preparation of Active Silicate Particle Dispersion (3)

Of the concentration as a SiO ₂ 24% by weight sodium silicate aqueous solution (SiO ₂ / Na ₂ O molar ratio of 3.1) was diluted with ion-exchanged water, the concentration of SiO ₂ as to prepare a dilute aqueous solution of sodium silicate, 5.2% by weight. Sulfuric acid was added to this aqueous sodium silicate solution and neutralized to prepare a silica hydrogel. After sufficiently washing the silica hydrogel with water, a silica hydrogel dispersion having a concentration of SiO ₂ of 5% by weight was added, and 555 g of a 20% by weight aqueous NaOH solution was added to 25 kg of the silica hydrogel dispersion, followed by 3 hours at 80 ° C. It peptized to prepare an active silicate particle dispersion (3). SiO ₂ concentration in this case is 3% by weight, the number of moles of SiO ₂ (M _S) and alkali (expressed as M ₂ O) molar number ratio _(S M) / (M _A) with _(A M) of was 25. In addition, the average particle diameter (D _LF ) measured by the dynamic light scattering method by a laser beam was 4 nm, and the average particle diameter (D _NaF ) measured by the NaOH titration method was 2 nm.

Preparation of silica sol (3)

To 410 g of the seed particle dispersion (2) prepared at a temperature of 80 ° C, 24556 g of the active silicate particle dispersion (3) was added for 15 hours to prepare a silica sol (3). As in Example 1, SiO ₂ concentration, average particle diameter, and particle growth rate of the silica sol are shown in Table 1.

Example 4

Preparation of Active Silicate Particle Dispersion (4)

Of the concentration as a SiO ₂ 24% by weight sodium silicate aqueous solution (SiO ₂ / Na ₂ O molar ratio of 3.1) was diluted with ion-exchanged water, the concentration of SiO ₂ as to prepare a dilute aqueous solution of sodium silicate, 5.2% by weight. Sulfuric acid was added to this aqueous sodium silicate solution and neutralized to prepare a silica hydrogel. After sufficiently washing the silica hydrogel with water, a silica hydrogel dispersion having a concentration of SiO ₂ of 5% by weight was added, and 167 g of an aqueous NaOH solution having a concentration of 20% by weight was added to 35 kg of the silica hydrogel dispersion, and the mixture was heated at 80 ° C for 3 hours. Peptides prepared an active silicate particle dispersion (4). SiO ₂ concentration in this case is 3% by weight, the number of moles of SiO ₂ (M _S) and alkaline (C represented by M ₂ O) molar number (M _A) ratio _{(M S) / (M A} ) with the was 70. In addition, the average particle diameter (D _LF ) measured by the dynamic light scattering method by a laser beam was 8 nm, and the average particle diameter (D _NaF ) measured by the NaOH titration method was 2 nm.

Preparation of silica sol (4)

To 410 g of the seed particle dispersion (2) prepared at a temperature of 80 ° C, 24556 g of the active silicate particle dispersion (4) was added for 15 hours to prepare a silica sol (4). As in Example 1, SiO ₂ concentration, average particle diameter, and particle growth rate of the silica sol are shown in Table 1.

Example 5

Preparation of seed particle dispersion (3)

Reflux group was diluted in a stainless steel vessel of a stirrer, a 30L with a temperature sensing device, the a sodium silicate aqueous solution has a concentration as a SiO ₂ 24% by weight of (SiO ₂ / Na ₂ O molar ratio of 3.1) 163g with ion exchange water 2760g . 25220 g of the acidic silicic acid solution prepared in the same manner as in Example 1 was mixed with this solution, and then heated at 90 ° C. for 30 minutes to prepare a seed particle dispersion 3 having a concentration of 4.6 wt% as SiO ₂ . The mean particle size of the seed particles measured by a dynamic light scattering method with the laser light (D _LS) was 25nm, SiO ₂ / Na ₂ O mole ratio of 100.

Preparation of Active Silicate Particle Dispersion (5)

According to the preparation method of the active silicate particle dispersion (1), only 480 g of NaOH aqueous solution having a concentration of 20% by weight was prepared, and the active silicate particle dispersion (5) was prepared in the same manner except that it was peptized at 90 ° C. SiO ₂ concentration at this time was 3% by weight, the number of moles of SiO ₂ (M _S) and alkali (expressed as M ₂ O) molar number _(A M) ratio _{(M S) / (M A} ) of between 30. In addition, the average particle diameter (D _LF ) measured by the dynamic light scattering method by a laser beam was 12 nm, and the average particle diameter (D _NaF ) measured by the NaOH titration method was 2 nm.

Preparation of silica sol (5)

12382 g of the active silicate particle dispersion (5) was added to 410 g of the seed particle dispersion (3) adjusted to a temperature of 87 ° C for 17 hours to prepare a silica sol (5). As in Example 1, SiO ₂ concentration, average particle diameter, and particle growth rate of the silica sol are shown in Table 1.

Example 6

Preparation of seed particle dispersion 4

In a 30 L stainless steel vessel equipped with a refluxer, a stirrer, and a temperature detector, cataloid S1-80P (manufactured by Shokubai Chemical Co., Ltd.) was mixed with 363 g of ion-exchanged water, and the concentration as SiO ₂ was 4.6% by weight. Phosphorus seed particle dispersion 4 was prepared. The mean particle size of the seed particles measured by a dynamic light scattering method with the laser light (D _LS) was 100nm, SiO ₂ / Na ₂ O mole ratio of 100.

Preparation of Active Silicate Particle Dispersion (6)

According to the preparation method of the active silicate particle dispersion (1), the active silicate particle dispersion (6) was prepared in the same manner except that only an aqueous NaOH solution having a concentration of 20% by weight was 320g. SiO ₂ concentration in this case is 3% by weight, the number of moles of SiO ₂ (M _S) and an alkali number of moles (M _A) ratio _{(M S) / (M A} ) with a (represented by M ₂ O) was 45. Further, the average particle diameter measured by a dynamic light scattering method with the laser light _(LF D) has a mean particle size of 20nm as measured by, NaOH titration (D _NaF) was 2nm.

Preparation of Silica Sol (6)

2728 g of active silicate particle dispersion (6) was added to 410 g of seed particle dispersion (4) prepared at a temperature of 95 ° C for 20 hours to prepare silica sol (6). As in Example 1, SiO ₂ concentration, average particle diameter, and particle growth rate of the silica sol are shown in Table 1.

Example 7

Preparation of Active Silicate Particle Dispersion (7)

Of the concentration as a SiO ₂ 24% by weight sodium silicate aqueous solution (SiO ₂ / Na ₂ O molar ratio of 3.1) was diluted with ion-exchanged water, the concentration of SiO ₂ as to prepare a dilute aqueous solution of sodium silicate, 5.2% by weight. Sulfuric acid was added to this aqueous sodium silicate solution and neutralized to prepare a silica hydrogel. After sufficiently washing the silica hydrogel with water, it was prepared as a silica hydrogel dispersion having a concentration of SiO ₂ of 3% by weight, and this was treated with a grinder (manufactured by Yasugawa Denki Co., Ltd .: sand mill) for 0.5 hour, and activated silicic acid The particle dispersion 7 was prepared. At this time, the SiO ₂ concentration was 3% by weight and the average particle diameter (D _LF ) measured by the dynamic light scattering method by laser light was 3 nm, and the average particle diameter (D _NaF ) measured by the NaOH titration method was 1 nm.

Preparation of silica sol (7)

42716 g of the active silicate particle dispersion (7) was added to 410 g of the seed particle dispersion (1) prepared at a temperature of 80 ° C for 11 hours to prepare a silica sol (7). As in Example 1, the SiO ₂ concentration, average particle diameter, and particle growth rate of the silica sol are shown in Table 1.

Example 8

Preparation of seed particle dispersion 5

According to the preparation method of the seed particle dispersion 4, the seed particle dispersion 5 was similarly prepared except having made Cataloid S1-80P into Spherica slurry 100P (made by Shokubai Chemical Co., Ltd.). The mean particle size of the seed particles is determined by the time of the SiO ₂ concentration is 4.6 weight%, a dynamic light scattering method with the laser light (D _LS) was 120nm. The SiO ₂ / Na ₂ O molar ratio was 100.

Preparation of Active Silicate Particle Dispersion (8)

According to the preparation method of the active silicate particle dispersion (1), the active silicate particle dispersion (8) was prepared in the same manner except that only the aqueous NaOH solution having a concentration of 20% by weight was 285g. SiO ₂ concentration in this case is 3% by weight, the number of moles of SiO ₂ (M _S) and alkali (expressed as M ₂ O) molar number ratio _(S M) / (M _A) with _(A M) of was 15. In addition, the average particle diameter (D _LF ) measured by the dynamic light scattering method by a laser beam was 40 nm, and the average particle diameter (D _NaF ) measured by the NaOH titration method was 2 nm.

Preparation of Silica Sol (8)

To 410 g of the seed particle dispersion (5) prepared at a temperature of 150 ° C, 1600 g of the active silicate particle dispersion (8) was added over 20 hours to prepare a silica sol (8). As in Example 1, the SiO ₂ concentration, average particle diameter, and particle growth rate of the silica sol are shown in Table 1.

Comparative Example 1

Preparation of Active Silicate Particle Dispersion (9)

According to the preparation method of the active silicate particle dispersion (1), the active silicate particle dispersion (9) was prepared in the same manner except that only the aqueous NaOH solution having a concentration of 20% by weight was 950 g. SiO ₂ concentration in this case is 3% by weight, the number of moles of SiO ₂ (M _S) and alkali (expressed as M ₂ O) molar number ratio _(S M) / (M _A) with _(A M) of was 15. In addition, the average particle diameter (D _LF ) measured by the laser beam was 3 nm, and the average particle diameter (D _NaF ) measured by the NaOH titration method was 2 nm.

Preparation of silica sol (9)

1744 g of the active silicate particle dispersion (9) was added to 400 g of the seed particle dispersion (2) prepared at a temperature of 80 ° C. over 15 hours to prepare a silica sol (9). As in Example 1, the SiO ₂ concentration, average particle diameter, and particle growth rate of the silica sol are shown in Table 1.

Comparative Example 2

Preparation of Active Silicate Particle Dispersion (10)

According to the preparation method of the active silicate particle dispersion (1), the active silicate particle dispersion (10) was prepared in the same manner except that only 240 g of NaOH aqueous solution having a concentration of 20% by weight was used. SiO ₂ concentration in this case is 3% by weight, the number of moles of SiO ₂ (M _S) and alkali (expressed as M ₂ O) molar number ratio _(S M) / (M _A) with _(A M) of was 60. In addition, the average particle diameter (D _LF ) measured by the laser beam was 80 nm, and the average particle diameter (D _NaF ) measured by the NaOH titration method was 2 nm.

Preparation of Silica Sol (10)

1744 g of the active silicate particle dispersion (10) was added to 400 g of the seed particle dispersion (3) prepared at a temperature of 87 ° C over 15 hours to prepare a silica sol (10). As in Example 1, the SiO ₂ concentration, average particle diameter, and particle growth rate of the silica sol are shown in Table 1.

TABLE 1

[Industry availability]

In particular, the silica sol of the present invention can be suitably used as an abrasive such as a hard coat agent, a plastic filler, a lens or a silicon wafer of a transparent base material such as transparent plastic or glass.

According to the method for producing a silica sol according to the present invention, since active reactive silica particles having a predetermined range of particle diameters are attached to the surface of seed particles to grow particles, the grain growth can be performed quickly. Accordingly, the production time of the silica sol is shortened, which is very economical. Moreover, a silica sol containing silica particles having a uniform and large particle diameter can be obtained.

Claims (5)

The method for producing a silica sol comprising adding the active silicate particle dispersion liquid of the following (b) to the seed particle dispersion of the following (a) continuously or intermittently while heating, and attaching the active silicate particle to the seed particle to grow the particles. . (a) An aqueous dispersion of seed particles having an average particle diameter (D _LS ) measured in the range of 5 to 1000 nm as measured by dynamic light scattering by a laser beam, the seed particle dispersion having a pH of 7 to 12 (b) the average particle diameter (D _LF ) measured by the dynamic light scattering method by laser light is in the range of 2 to 50 nm, provided that the average particle diameter (D _LF ) is smaller than the average particle diameter (D _LS ); Furthermore, the average particle diameter (D _NaF ) measured by NaOH titration method is in the range of 0.9 to 6 nm, and further, the ratio of the average particle diameter (D _LF ) and the average particle diameter (D _NaF ) (D _LF ) / (D An aqueous silicate dispersion of active silicate particles having _NaF ) in the range of 1.8 to 30, wherein the active silicate particle dispersion having a pH in the range of 5 to 11. The method for producing a silica sol according to claim 1, wherein said heating is performed at a temperature range of 60 to 160 캜. The active silicate particles according to claim 1 or 2, wherein the active silicate particles are obtained by peptizing (a) an alkali silicate produced by neutralizing an alkali silicate with an acid, and then bridging the silica hydrogel with an alkali, or (b) alkali silicate as an acid. A method for producing a silica sol, characterized in that the activated silica particles are obtained by mechanically miniaturizing while neutralizing the silica hydrogel produced by neutralization. Article according to one of the preceding claims, wherein the mean particle size of the active silicic acid particles (D _LF) is, when the average particle diameter (D _LS) of the seed particles less than 12nm, the average particle diameter (D _LS) 7/10 or less, and when the average particle diameter (D _LS ) of the said seed particle exceeds 12 nm, it is 5/10 or less of the said average particle diameter (D _LS ), The manufacturing method of the silica sol characterized by the above-mentioned. delete