JP3235097B2 - Modified metal oxide sol and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention coats the surface of tri- to pentavalent metal oxide colloidal particles with 2 to 7 millimicron tungsten oxide-tin oxide composite colloidal particles. The present invention relates to a sol of modified colloidal particles of trivalent to pentavalent metal oxide having a particle diameter of about 4.5 to 60 millimicrons and a method for producing the same.

The sol of the present invention is used for various other purposes as a component of a hard coat agent applied to the surface of a plastic lens.

(Prior Art) Sols of various metal oxides are already known.

In order to improve the surface of a plastic lens that has been widely used in recent years, a metal oxide sol having a high refractive index is used as a component of a hard coat agent applied to the surface.

For example, Japanese Patent Publication No. 63-37142 discloses Al, Ti, Zr, Sn, S
Hard coating agents containing 1 to 300 millimicron particles of metal oxides such as b are described.

A stable sol of tungsten oxide alone is not yet known, but WO ₃ : SiO ₂ : M ₂ O obtained by adding silicate
(However, M represents an alkali metal atom or an ammonium group.) A sol having a molar ratio of 4 to 15: 2 to 5: 1 is disclosed in
It is proposed in Japanese Patent Application Laid-Open No. 4-52686.

Japanese Patent Publication No. 50-40119 proposes a silicate-stannate composite sol having a molar ratio of Si: Sn of 2 to 1000: 1.

(Problems to be Solved by the Invention) However, when these conventional metal oxide sols, particularly cationic metal oxide sols, are used as components of the hard coat agent, the stability of the obtained hard coat agent is not sufficient. Instead, the transparency of the cured film of this hard coat agent,
Adhesion and weather resistance are not sufficient. Further, when the Sb ₂ O ₅ sol is used as a hard coating agent component, the refractive index of Sb ₂ O ₅ is about 1.65 to 1.70. Sb ₂ O ₅ sol does not sufficiently improve the refractive index of the cured film.

The sol of tungsten oxide described in Japanese Patent Application Laid-Open No. 54-52686 is an aqueous solution of tungstic acid obtained by subjecting an aqueous solution of tungstate to decation treatment.
Although it is obtained by adding a silicate, it is stable only in strong acidity, and when used as a component of a hard coat agent, the effect of improving the refractive index of the coating film is small.

The silicic acid-stannic acid composite sol described in JP-B-50-40119 is obtained by subjecting a mixed aqueous solution of alkali silicate and alkali stannate to decation treatment,
Similarly to the above, when used as a component of a hard coat agent, the effect of improving the refractive index of the coating film is small.

The present invention seeks to provide a stable sol of metal oxide colloid particles having a high refractive index, especially a refractive index of 1.7 or more.

Still another object of the present invention is to provide a metal oxide sol which can be used as a component for improving the performance of a hard coat film applied to the surface of a plastic lens, which can be mixed with a paint for the hard coat.

(Means for Solving the Problems) The present invention is based on colloidal particles of metal oxides having a valence of 3, 4 or 5 having a particle diameter of 4 to 50 millimicrons, and the surface of which is WO ₃ / SnO ₂ weight 0.5 to 100 ratio and particle size 2
A modified metal oxide sol comprising modified metal oxide colloid particles having a particle diameter of 4.5 to 60 millimicrons formed by being coated with tungsten oxide-tin oxide composite colloid particles having a particle size of ７7 millimicrons, The modified metal oxide colloid particles have a ratio of 2 to 100 parts by weight of a tungsten oxide-tin oxide complex with respect to 100 parts by weight of a metal oxide having a valence of 3, 4 or 5; 2 to 2 in the above sol as all metal oxides
The modified metal oxide sol is contained in an amount of 50% by weight.

The sol of the modified metal oxide colloidal particles having a particle diameter of 4.5 to 60 mm, which is surface-coated with the colloidal particles of the tungsten oxide-tin oxide composite of the present invention, is 0.5 to 5 μm.
0% by weight of a metal oxide having a valence of 3, 4 or 5 and 4 to 5
100 parts by weight of the sol of the metal oxide colloid particles having a particle size of 0 millimicron as the metal oxide,
Tungsten oxide having a particle diameter and WO ₃ / SnO ₂ weight ratio and WO ₃ and SnO ₂ total concentration of 0.5 to 40% by weight of 0.5 to 100 2-7 millimicrons - the sol colloidal particles consisting of tin oxide composite By mixing the WO ₃ and SnO _{2 in} a ratio of 2 to 100 parts by weight in total at 0 to 100 ° C., or if necessary,
It is obtained by concentrating the sol obtained by this mixing.

Examples of the water-soluble tungstate and water-soluble stannate used for producing the tungsten oxide-tin oxide composite sol of the present invention include tungstates and stannates of alkali metals, ammonium or water-soluble amines. . Preferred examples of these alkali metals, ammonium and amine include Li, Na, K, Rb, Cs, NH ₄ , ethylamine,
Triethylamine, isopropylamine, n-propylamine, isobutylamine, diisobutylamine, di (2
Alkylamines such as -ethylhexyl) amine; aralkylamines such as benzylamine; alicyclic amines such as piperidine; alkanolamines such as monoethanolamine and triethanolamine. Particularly, sodium tungstate Na ₂ WO ₄ · 2H ₂ O and sodium stannate Na
₂ SnO ₃ .3H ₂ O is preferred. Also, a solution in which tungsten oxide, tungstic acid, stannic acid, or the like is dissolved in an aqueous solution of an alkali metal hydroxide can be used.

The hydrogen-type cation exchanger used may be a conventional one, and a hydrogen-type cation exchange resin can be conveniently obtained as a commercial product. Commercially available industrial products may also be used for alkali metal hydroxides, ammonium hydroxide, amines, and the like used in some cases. Examples of the alkali metal hydroxide include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like.

The aqueous solution of tungstic acid used can be easily obtained by treating the aqueous solution of tungstate with the above cation exchange resin at a temperature of 100 ° C. or lower, preferably room temperature to about 60 ° C. Since the aqueous solution of tungstic acid has a property of being easily gelled due to its colloidal property, it is preferably used before the gelation. The aqueous solution of the tungstate used to make the aqueous solution of the tungstate, WO ₃ as a 0.1 to 15 wt%
Preferably having density, also as an aqueous solution of tungstic acid, the WO ₃ concentration is preferably about 0.1 to 15 wt%.

The aqueous solution of the stannate used has a SnO ₂ concentration of 0.1
It is preferably about 30% by weight, but may be higher.
In some cases, a solid stannate can also be used.

The production of the tungsten oxide-tin oxide composite sol according to the present invention is performed by mixing the aqueous solution of tungstic acid and the aqueous solution of stannate. This mixing is carried out under sufficient stirring at a temperature higher than the temperature at which the liquid freezes, at 100 ° C. or lower, preferably at room temperature to about 60 ° C. The amount of liquid to be mixed is preferably about 0.5 to 100 by weight of WO ₃ / SnO ₂ , and particularly preferably 2 to 100. This mixing can be completed in about 5 to 100 minutes, preferably about 30 to 60 minutes. The mixed liquid obtained by this mixing usually contains the alkali metal ion, ammonium ion, amine and the like. When these alkali metal atoms, NH ₄ or amine molecules are represented by M, WO ₃ and SnO
The ratio of the number of moles of M ₂ O contained the total number of moles of ₂ M ₂ O / (WO
₃ + SnO ₂₎ is about .01 to .44.

In order to obtain a tungsten oxide-tin oxide composite sol with high stability, M ₂ O / (WO ₃
+ SnO ₂ ) The molar ratio is preferably adjusted to about 0.02 to 0.7.
As a method of increasing the molar ratio in the liquid obtained by the above mixing, it can be carried out by adding an alkali metal oxide, ammonium hydroxide, an amine or the like to the mixed liquid. After treatment with a cation exchange resin, alkali metal hydroxide, ammonium hydroxide, ammonium hydroxide, and the like are used such that the molar ratio of M ₂ O / (WO ₃ + SnO ₂ ) is 0.02 to 0.7.
It can be performed by adding an amine or the like.

WO contained in the tungsten oxide-tin oxide composite sol after the above mixing or after the above molar ratio adjustment
Colloid particles composed of a complex of ₃ and SnO ₂ can be observed by an electron microscope, and usually have a size of 7 mm or less, and a preferable sol particle size is usually 2 to 2.
5 micron.

When it is desired to increase the concentration of the tungsten oxide-tin oxide composite sol obtained by the above method, a usual concentration method,
For example, the concentration of the sol can be increased by an evaporation method, an ultrafiltration method, or the like. In particular, the ultrafiltration method is preferable. Also in this concentration, the temperature of the sol is about 100 ° C. or less, particularly 60 ° C.
It is preferable to keep the following. However, enrichment as high as 40% by weight or more as a total concentration of WO ₃ and SnO ₂ is preferably avoided because the stability of the sol becomes poor. The practically preferable concentration is 2% by weight or more, particularly preferably about 10 to 30% by weight.

Preferred tungsten oxide obtained as described above
The aqueous sol of the tin oxide complex usually shows a pH of 1 to 9,
It is a colorless, transparent or almost transparent liquid. The room temperature is stable for 3 months or more, and at 60 ° C. for 1 month or more. No sediment is formed in the sol, and the sol does not increase in viscosity or cause gelation. .

By replacing water in the aqueous sol with a hydrophilic organic solvent, a hydrophilic organic solvent sol called an organosol is obtained. Examples of the hydrophilic organic solvent include lower alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol; linear amides such as dimethylformamide and N, N'-dimethylacetamide; cyclic amides such as N-methyl-2-pyrrolidone And glycols such as ethyl cellosolve, butyl cellosolve, and ethylene glycol.

The replacement of the water with the hydrophilic organic solvent can be easily performed by a usual method, for example, a distillation replacement method, an ultrafiltration method, or the like. When the pH of the aqueous sol is high, before or simultaneously with the above substitution, an oxycarboxylic acid such as lactic acid, tartaric acid, citric acid, gluconic acid, malic acid or glycolic acid is added to the aqueous sol in the total amount of WO ₃ and SnO ₂ . About 30% by weight or less with respect to Regardless of the presence or absence of this oxycarboxylic acid, the temperature of the sol is about 100 even when the medium of the sol is replaced.
It is preferable to keep the temperature at or below 60 ° C.

The colloidal particles of the tungsten oxide-tin oxide composite sol obtained as described above are treated with another valence of 3, 4 or 5
Oxides such as Al ₂ O ₃ , Y ₂ O ₃ , Sb ₂ O ₃ , In ₂ O ₃ , Bi _{2
O 3, TiO 2, ZrO 2} , SnO 2, CeO 2, TeO 2, Sb 2 O 5, Nb 2 O 5, is coupled to the colloidal particle surface of the sol, such as Ta ₂ O ₅ in said tungsten oxide the surface By coating with the colloidal particles of the tin oxide composite, the surface of the metal oxide having the valence of 3 to 5 modified with the colloidal particles as nuclei and having the surface having the properties of the tungsten oxide-tin oxide composite. Colloidal particles can be produced and the modified colloidal particles can be obtained as a sol stably dispersed in a liquid medium.

The colloidal particles of the trivalent to pentavalent metal oxide used can be formed in a known method, for example, about 4 to 50 millimicrons by a method called an ion exchange method, a peptization method, a hydrolysis method, a reaction method, or the like. In the form of a sol of colloidal particles having a particle size of

Examples of the ion exchange method include a method of treating the acidic salt of the metal with a hydrogen-type cation exchange resin, and a method of treating the basic salt of the metal with a hydroxyl-type anion exchange resin. Examples of the deflocculation method include neutralizing the acidic salt of the metal with a base, or washing the gel obtained by neutralizing the basic salt of the metal with an acid, and then pulverizing with an acid or a base. Glue method. Examples of the hydrolysis method include a method of hydrolyzing an alkoxide of the metal or a method of hydrolyzing a basic salt of the metal under heating and then removing an unnecessary acid. Examples of the reaction method include a method of reacting the metal powder with an acid.

The medium of these metal oxide sols may be either water or a hydrophilic organic solvent, but an aqueous sol in which the medium is water is preferred. Further, the pH of these sols is preferably a value that stabilizes the sol, and is generally preferably about 1 to 9. As long as the object of the present invention is achieved, these metal oxide sols include optional components, for example, an alkaline substance for stabilizing the sol,
An acidic substance, an oxycarboxylic acid and the like may be contained.
The concentration of the metal oxide sol used is about 0.5 to 50% by weight as the metal oxide, but the lower the concentration, the better, preferably 1 to 30% by weight. Further, as long as the stable sol of the present invention can be obtained, a mixture of two or more sols can be used.

The sol of these trivalent to pentavalent metal oxide colloidal particles modified by the above-described tungsten oxide-tin oxide composite colloidal particles contains 100 parts by weight of these trivalent to pentavalent metal oxide sol as the metal oxide. the tungsten oxide - the ratio of 2 to 100 parts by weight of tin oxide composite sol as the sum of WO ₃ and SnO ₂ of the sol is preferably obtained by mixing under stirring strong. This mixture is 0-100 ° C
, Preferably at room temperature to 60 ° C. This mixing can be completed in about 5 to 10 minutes, preferably about 30 to 60 minutes. Sol colloidal particles modified to be obtained by the mixing, to contain a total of from 2 to 40% by weight of the 3-5-valent metal oxides and WO ₃ and SnO _2, tungsten oxide used in the above mixed - It is preferable to select the concentration of the tin oxide composite sol and the concentration of the trivalent to pentavalent metal oxide sol before the mixing, and then mix these two sols. However, when it is desired to further increase the concentration of the sol obtained by this mixing, the sol can be concentrated to a maximum of about 50% by weight by a conventional method such as an evaporation method and an ultrafiltration method.

The modified colloidal particles in the sol obtained by the above mixing can be observed by an electron microscope and have a particle size of approximately 4.5 to 60 millimicrons. The sol obtained by the above mixing has a pH of about 1 to 9 and is stable. When it is desired to adjust the pH of the sol, it is carried out by adding the hydroxide of alkali metal, ammonium or the like, the amine, oxycarboxylic acid or the like to the sol after the above-mentioned mixing or the above-mentioned concentration in a pH range of about 1 to 9. be able to. In particular, the total concentration of the metal oxide and WO ₃ and SnO ₂ is 10
Sols that are 〜40% by weight are practically preferred.

When the modified metal oxide sol obtained by the mixing is an aqueous sol, an organosol is obtained by replacing the aqueous medium of the aqueous sol with a hydrophilic organic solvent. This substitution can be performed by a usual method such as a distillation method and an ultrafiltration method. Examples of the hydrophilic organic solvent include lower alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; linear amides such as dimethylformamide, N, N'-dimethylacetamide;
Cyclic amides such as methyl-2-pyrrolidone; and glycols such as ethyl cellosolve, butyl cellosolve, and ethylene glycol.

(Operation) Both the colloidal particles of the tungsten oxide-tin oxide composite according to the present invention and the colloidal particles of the modified trivalent to pentavalent metal oxide whose surface is coated with the particles are negatively charged in the sol. Particles were found. Except for the colloidal particles of Sb ₂ O ₅ ,
Since the surface of the colloidal particles of the valent metal oxide is positively charged, the mixing causes the negatively charged tungsten oxide-tin oxide composite colloidal particles to surround the positively charged colloidal particles. The tungsten oxide-tin oxide composite colloid particles are electrically attracted and bound by chemical bonding on the surface of the positively charged colloidal particles, and the surface of the tungsten oxide-tin oxide composite is formed with the positively charged particles as nuclei. Is covered by
It is considered that the modified colloid particles of the trivalent to pentavalent metal oxide were formed. However, since the Sb ₂ O ₅ colloidal particles are not positively charged, the surface of the colloidal particles of tungsten oxide is not affected by the electrostatic attraction of the particles themselves, but by a different force.
Tungsten oxide Sb ₂ O ₅ colloidal particles surface by the colloidal particles of tin oxide composite was drawn - is believed that the colloidal particles of tin oxide complex bound. A sol of these generated negatively charged colloidal particles,
When a well-known negatively charged silica sol is mixed, a stable mixed sol can be obtained without aggregation of colloid particles. Any of the coated modified trivalent to pentavalent metal oxide colloid particles,
This indicates that the colloidal particles are negatively charged enough to maintain a stable sol.

However, the particle diameter of the trivalent or pentavalent metal oxide is 4 to 50.
And sol colloidal particles millimicrons, tungsten oxide - when mixing the sol of tin oxide composite colloidal particles, the total amount of WO ₃ and SnO ₂ is less than 2 parts by weight per the metal oxide 100 parts by weight , A stable sol cannot be obtained.
This means that when the amount of the colloidal particles of the tungsten oxide-tin oxide complex is insufficient, the surface of the metal oxide colloidal particle with the core of the metal oxide colloidal particle is insufficiently coated by the composite colloidal particle, and the produced colloidal particle It is considered that aggregation easily occurs and the resulting sol becomes unstable. Therefore, the amount of the tungsten oxide-tin oxide composite colloid particles to be mixed may be smaller than the amount covering the entire surface of the metal oxide colloid particles, but it is necessary to form a stable modified metal oxide colloid particle sol. More than the minimum required. When an amount of the tungsten oxide-tin oxide composite colloid particles exceeding the amount used for the surface coating was used in the above mixing, the obtained sol was formed as a sol of the tungsten oxide-tin oxide composite colloid particles. It is only a stable mixed sol with the sol of the modified metal oxide colloid particles.

Preferably, to modify the metal oxide colloid particles by their surface coating, the tungsten oxide used
The amount of the colloidal particles of the tin oxide complex depends on the WO in the composite sol.
_As a total of ₃ and SnO ₂ , 10 parts by weight of metal oxide, 10
0 parts by weight or less is preferred.

Preferred aqueous sols of the modified metal oxides according to the invention have a pH of 1 to 9; when the pH is lower than 1, such sols tend to be unstable. Also, if this pH exceeds 9,
The tungsten oxide-tin oxide composite covering the modified metal oxide colloid particles is easily dissolved in the liquid. Further, the above metal oxide in the sol of the modified metal oxide colloid particles and WO ₃
Even when the total concentration of SnO ₂ and SnO ₂ exceeds 50% by weight, such a sol tends to be unstable. The preferred concentration as an industrial product is about 10 to 40% by weight.

When mixing the tri- to pentavalent metal oxide sol and the tungsten oxide-tin oxide composite sol, both the metal oxide concentration and the total concentration of WO ₃ and SnO ₂ in these sols are 50%.
It is not preferable to use a sol in excess of the weight% because gelation may occur during the mixing. Rather, the concentration of the sol used is preferably low, but too low a concentration results in an increase in the amount of liquid to be removed when the sol obtained by mixing is concentrated. Also, at the time of this mixing,
When performed at a high temperature of 100 ° C. or more, the tungsten oxide-tin oxide composite colloid particles are easily susceptible to hydrolysis.

SnO ₂ sol, ZrO ₂ sol,
When a TiO ₂ sol, Sb ₂ O ₅ sol, or the like is used, a sol of the present invention having sufficient stability, colloidal particle size, and modified metal oxide colloidal particle refractive index can be obtained.

If the sol of the colloidal particles of the tungsten oxide-tin oxide composite is not prepared by a preferable method, only a sol having poor practicality can be obtained.

Sol obtained by mixing an aqueous solution of tungstic acid obtained by treating an aqueous solution of tungstate with a hydrogen-type cation exchange resin and an aqueous solution of stannate in a WO ₃ / SnO ₂ weight ratio of 2 to 100 The stability of the stannic acid is as follows: the colloidal particles of tin oxide and tin oxide formed by the mixing of the colloidal particles of tin oxide and the colloidal particles of tungsten oxide or the polyanion which is a low polymer of tungstic acid are combined with the stannic acid. It is considered that the cations such as alkali metal, ammonium, and amine introduced by the salt acted as a stabilizing counter ion to generate stable colloidal particles.

However, when the weight ratio of WO ₃ / SnO ₂ in the obtained sol is less than 0.5, the sol is unstable when it is acidic, and when the weight ratio exceeds 100, the sol still does not show stability. The amount of cations such as alkali metal, ammonium, and amine contained in the sol is M ₂ O / (WO ₃ + SnO ₂ )
When the molar ratio is less than 0.01, such a sol has poor stability, and when the molar ratio exceeds 0.7,
The water resistance of a dried coating film obtained using such a sol is low, which is not preferable in practical use. The oxycarboxylic acid added when preparing the above-mentioned organosol from an aqueous sol having a high pH also contributes to the stabilization of the sol, but the amount added is
When WO ₃ and the sum of SnO ₂ with respect to greater than 30 wt%, it decreases the water resistance of the dried coating obtained using such a sol. The pH of the sol changes according to the amount of the alkali metal, ammonium, amine, oxycarboxylic acid and the like in the sol. If the pH of the sol is 1 or less, the sol is unstable, and if the pH is 9 or more, the colloidal particles of the composite of tungsten oxide and tin oxide are easily dissolved in the liquid. If the total concentration of WO ₃ and SnO _{2 in} the sol is as high as 40% by weight or more, the sol still has poor stability. If this concentration is too low, it is impractical and the preferred concentration for an industrial product is 10 to 30% by weight.

When an aqueous solution in which a tungstate and a stannate are dissolved is treated with a hydrogen-type cation exchange resin instead of the production method of the present invention, the formed colloid particles are too small or tin oxide is likely to precipitate. The method of producing a sol by adding the alkali metal hydroxide, ammonium hydroxide, amine or the like to the liquid obtained by the treatment with the hydrogen-type cation exchange resin is not efficient.

When the aqueous solution of tungstic acid used has a WO ₃ concentration of 0.1% by weight or less, the concentration of the obtained sol decreases,
It is not efficient because a large amount of water is required for concentration. Conversely, if the aqueous solution of tungstic acid has a WO ₃ concentration as high as 15% by weight or more, such an aqueous solution is poor in stability and tends to be difficult to handle.

When the ultrafiltration method is used in the concentration, the polyanion, ultrafine particles, etc. of tungsten oxide coexisting in the sol pass through the ultrafiltration membrane together with water, and these cause the instability of the sol. Polyanions, ultrafine particles and the like can be removed from the sol. At a temperature of 100 ° C. or higher, the aqueous sol of the colloidal particles of the tungsten oxide-tin oxide composite dissolves due to the hydrolysis of the composite colloidal particles of tungsten oxide and tin oxide in the sol, Since it is easy to precipitate, it is kept at 100 ° C. or less during the treatment with the cation exchange resin, mixing, concentration and the like. A safe temperature that does not cause such a change is preferably 60 ° C. or less.

(Examples) The present invention will be described in more detail with reference to the following Examples and Comparative Examples. However, the present invention is not limited by these examples.

Reference Example 1 Sodium tungstate _{Na 2 WO 4 · 2H 2 O} ( reagent first grade)
Was dissolved in 4850 g of water to obtain 5400 g of an aqueous solution of sodium tungstate. This aqueous solution has a specific gravity
1.086, pH9.79, were WO ₃ content of 7.16 wt%.

Next, the whole amount of the aqueous solution was passed through a column filled with a hydrogen-type cation exchange resin (Amberlite 120B, manufactured by Organo Corporation) to obtain 5690 g of an aqueous solution of tungstic acid. This aqueous solution has a specific gravity of 1.068, pH 1.60, viscosity of 2.0 cp, WO
₃ content was 6.8% by weight, Na ₂ O content was 0.04% by weight, and it was a yellow transparent liquid. Also, when this aqueous solution is left at room temperature,
After 1 hour, it turned into a gel.

Separately, sodium stannate Na ₂ SnO ₃ · 3H ₂ O (first grade reagent)
Was dissolved in water to obtain a sodium stannate aqueous solution having a specific gravity of 1.244, a pH of 12.8, a SnO ₂ content of 15.0% by weight, and a Na ₂ O content of 6.2% by weight.

Then, the aqueous solution of tungstic acid 5690 immediately after the above production
By adding 505 g of the above aqueous solution of sodium stannate to the g under strong stirring at room temperature, a tungsten oxide-tin oxide composite aqueous sol that can be used in the present invention was obtained. This sol had a slightly colloidal color, but was almost colorless and transparent. And specific gravity 1.073, pH 5.03, viscosity 1.5
The content of cp and WO _{3 was} 6.25% by weight, the content of SnO _{2 was} 1.22% by weight, the content of Na ₂ O was 0.54% by weight, and the colloidal particle diameter determined by electron microscopic observation was about 5 mm. Further, this sol had stability of 3 months or more when left at room temperature in a sealed state. From the above values, the value of the weight ratio WO ₃ / SnO ₂ of WO ₃ and SnO ₂ in this sol is
5.12, the value of the molar ratio of Na ₂ O / WO ₃ + SnO ₂ is calculated to be 0.25, respectively.

Reference Example 2 By passing 3100 g of the aqueous sol obtained in Reference Example 1 through a column filled with a hydrogen-type cation exchange resin, a specific gravity of 1.062, p
An aqueous sol having an H of 1.53, a viscosity of 1.5 cp, a WO ₃ content of 569% by weight, a SnO ₂ content of 1.11% by weight and a Na ₂ O content of 0.04% by weight was obtained, which can be used in the present invention. From the above values, the Na ₂ O / WO ₃ +
The SnO ₂ molar ratio is calculated to be 0.02.

Next, 3400 g of the sol having a pH of 1.53 and 3095 g of the sol having a pH of 5.03 obtained in Reference Example 1 were mixed at room temperature to obtain an aqueous sol that can be used in the present invention. The sol obtained here had a little colloidal color, but was almost colorless and transparent, specific gravity 1.068, pH 2.36, viscosity 1.5 cp, WO ₃ content
The content was 5.96% by weight, the content of SnO _{2 was} 1.17% by weight, the content of Na ₂ O was 0.28% by weight. It was stable for more than 3 months in a test at room temperature. Incidentally, when calculated from the above values, the WO ₃ / SnO ₂ weight ratio
5.12, the molar ratio of Na ₂ O / WO ₃ + SnO ₂ is 0.135.

Next, 6495 g of the pH 2.36 sol was concentrated by an ultrafiltration method to obtain 1840 g of a high-concentration sol. The sol also had little had colloidal color, is substantially colorless and transparent, specific gravity 1.212, PH2.34, viscosity 2.5 cP, WO ₃ content 17.
1 wt%, SnO ₂ content of 3.93 wt%, Na ₂ O content of 0.88 wt%,
Colloidal particle diameter of about 5 millimicrons by electron microscopy, dynamic light scattering method and a particle diameter 90 millimicrons by (US Apparatus Coulter N _4). The high-concentration sol had a WO ₃ / SnO ₂ weight ratio of 4.35 and a NaO / WO + SnO ₂ molar ratio of 0.14.
Is calculated. Further, the ultrafiltration reduces about 20% of WO _{3 in} the sol before the filtration. This decrease, polyanions or microfine particles of WO ₃ which passes through the ultrafiltration membrane indicating that was present in the sol before filtration.

Furthermore, when the above high concentration sol was tested,
The dispersion in methanol was good, and the stability was at least 3 months at room temperature. The dried sol was measured for refractive index to find that it was 1.84.

Reference Example 3 An aqueous solution of sodium tungstate having a WO ₃ content of 7.16% by weight (5400 g) was passed through a column filled with a hydrogen-type cation exchange resin to obtain 6135 g of an aqueous solution of tungstic acid.
This aqueous solution had a specific gravity of 1.062, a pH of 1.48, a viscosity of 2.5 cp, a WO ₃ content of 6.16% by weight, and a Na ₂ O content of 0.03% by weight. Therefore,
The Na ₂ O / WO ₃ molar ratio is calculated to be 0.018.

Then, an aqueous solution of tungstic acid 6135 immediately after the above production
g of an aqueous solution of sodium stannate (SnO ₂ content 15.0% by weight, Na ₂ O content 62% by weight) at room temperature under vigorous stirring to obtain an aqueous sol 6900 which can be used in the present invention.
g was obtained. This sol has a specific gravity of 1.073, pH 6.72, viscosity of 1.5c
p, WO ₃ content of 5.60 wt%, SnO ₂ content of 1.67 wt%, Na ₂ O content
0.71% by weight. By calculation, WO ₃ / SnO ₂ weight ratio 3.3
5. The molar ratio of Na ₂ O / WO ₃ + SnO ₂ is 0.33.

Next, the above sol was concentrated under reduced pressure by a rotary evaporator to obtain 1610 g of a high-concentration aqueous sol. The high concentration of the sol is slightly exhibited colloidal color is substantially colorless and transparent, specific gravity 1.385, PH6.68, viscosity 2.6cp, WO ₃ content of 24.0 wt%, SnO ₂ content of 7.14 wt%, Na
_{The 2} O content was 3.06% by weight, and the colloidal particle diameter determined by an electron microscope was about 5 mm. Even at room temperature standing test 3
It has been stable for more than a month.

Reference Example 4 The aqueous sol 325 having a specific gravity of 1.068 and a pH of 2.36 obtained in Reference Example 2.
An aqueous sol was obtained by adding 22 g of n-propylamine and 19 g of tartaric acid to 0 g with stirring. This sol has a specific gravity of 1.06
7, pH3.82, viscosity 1.5 cp, WO ₃ content of 5.88 wt%, SnO ₂ content
1.16 wt%, Na ₂ O content of 0.28 wt%, the amine content 0.67
% By weight and a tartaric acid content of 0.58% by weight. By calculation,
Na ₂ O + (amine) ₂ O / WO ₃ + SnO ₂ molar ratio 0.31, tartaric acid / WO ₃
+ SnO ₂ 9.52% by weight.

Next, this sol was concentrated under reduced pressure by a rotary evaporator to obtain 970 g of a high-concentration aqueous sol. This sol had a slightly colloidal color, but was almost colorless and transparent, specific gravity 1.282, pH 3.68, viscosity 2.3 cp, WO ₃
The content was 1.99 wt%, the SnO ₂ content was 3.93 wt%, the Na ₂ O content was 0.95 wt%, the amine content was 2.27 wt%, and the tartaric acid content was 1.97 wt%. This sol had good dispersibility in methanol and had stability of standing at room temperature for 3 months or more.

Reference Example 5 The aqueous sol 215 having a specific gravity of 1.212 and a pH of 2.34 obtained in Reference Example 2.
g was put into a rotary evaporator, and while the methanol 3 was continuously added little by little under the source pressure, the sol medium was distilled off to obtain 376 g of methanol sol in which water in the aqueous sol was replaced with methanol. Although this sol had a slightly colloidal color, it was almost colorless and transparent, had a specific gravity of 0.932, pH 3.46 (equivalent weight of the sol and water), a viscosity of 6.2 cp, and a WO ₃ content of 9.78% by weight. The SnO ₂ content was 2.25% by weight and the water content was 7.5% by weight. This sol produced a trace amount of sediment during standing, but the amount did not increase even if the standing period was extended, and was stable.

Reference Example 6 Regarding 300 g of the high-concentration aqueous sol obtained in Reference Example 4,
By replacing the water in the medium with methanol in the same manner as in Reference Example 5, 350 g of methanol sol was obtained. This sol
It has a slightly colloidal color, but is almost colorless and transparent, and has a specific gravity
0.978, pH5.28 (an equal weight mixture of the sol and water), the viscosity 4.0 cP, WO ₃ content of 17.1 wt%, SnO ₂ content of 3.37 wt%, Na
_{It had a} 2O content of 0.81% by weight, an n-propylamine content of 1.94% by weight, a tartaric acid content of 1.69% by weight, and a water content of 3.5% by weight.

Sodium Reference Example 7 tungstate Na ₂ WO ₄ · 2H ₂ O-in 240g water 32
To obtain an aqueous solution of sodium tungstate (WO ₃ 4.88 wt%) 3440g by dissolving in 200 g. Next, this aqueous solution was passed through a column filled with a hydrogen-type cation exchange resin, whereby 4450 g of an aqueous solution of tungstic acid (specific gravity 1.033, pH 1.5
3) got. Tungsten oxide-tin oxide composite sol (I) (specific gravity 1.042, pH 7.02) was prepared by mixing 366 g of an aqueous solution of sodium stannate Na ₂ SnO ₃ having a SnO ₂ content of 15.0% by weight, which was separately prepared, with 3440 g of the aqueous solution of tungstic acid. 3806g
I got Then acidic tungsten oxide by passing it to a column of a hydrogen type cation exchange resin - tin oxide composite sol (I) (specific gravity 1.032, pH1.82, WO ₃ 2.87 wt%, Sn
O ₂ 0.94% by weight to obtain a WO ₃ / SnO ₂ weight ratio of 3.07) 5860g. This acidic tungsten oxide-tin oxide composite sol (I) 58
413 g of the above sodium stannate aqueous solution (SnO ₂ 15.0%) in 60 g
Was mixed to obtain 6273 g of a tungsten oxide-tin oxide composite sol (II) (specific gravity 1.044, pH 7.26). This is then passed through a column packed with a hydrogen-type cation exchange resin to form an acidic tungsten oxide-tin oxide composite sol (I
I) (specific gravity 1.032, pH2.07, WO ₃ 2.22 wt%, SnO ₂ 1.55 wt%, to obtain a WO ₃ / SnO ₂ weight ratio of 1.44) 7556g.

This acidic tungsten oxide-tin oxide composite sol (I
I) The above sodium stannate aqueous solution (SnO ₂ 15.0%) in 7556 g
8001 g of a tungsten oxide-tin oxide composite sol (III) (specific gravity 1.040, pH 7.56) was obtained by mixing 445 g.
Next, 22,000 g of water was added to the composite sol, and the mixture was passed through a column filled with a hydrogen-type cation exchange resin to obtain an acidic tungsten oxide-tin oxide composite sol (III) (specific gravity 1.013,
PH2.61, viscosity 1.5 cp, WO ₃ 0.77 wt%, SnO ₂ 0.85 wt%,
WO ₃ / SnO ₂ weight ratio 0.92) was obtained.

Further, 8.0 g of isopropylamine was added to 21.7 kg of this acidic composite sol (III) to obtain a tungsten oxide-tin oxide composite sol (IV). This sol has a specific gravity of 1.013, pH 4.0 and viscosity
1.3cp, WO ₃ 0.77 wt%, SnO ₂ 0.85 wt%, WO ₃ / SnO ₂ 1.62
Weight% WO ₃ / SnO ₂ weight ratio 0.92, isopropylamine 0.03
7 wt%, (isopropylamine) ₂ O / (WO ₃ + SnO ₂ ) molar ratio 0.035, colloid particle diameter by electron microscope was 5 mμ or less, slightly colloidal color, and almost transparent sol.

Reference Example 8 In this reference example, aqueous SnO ₂ sol (A), aqueous Sb ₂ O ₅ sol (B) and aqueous ZrO ₂ sol (C) were prepared.

(1) Preparation of SnO ₂ sol (A) Specific gravity 1.420, pH 0.40, viscosity immediately after stirring obtained by reaction of metal tin powder, aqueous hydrochloric acid solution and aqueous hydrogen peroxide solution 3
2cp, SnO ₂ content 33.0% by weight, HCl content 2.56% by weight, spindle-shaped colloidal particle diameter less than 10 millimicron by electron microscope,
The specific surface area of the particles by the BET method 120 m ² / g, in terms of particle size 7.2 millimicrons from the specific surface area, USA Coulter N ₄
Dispersion of 200 g of a pale yellow transparent tin oxide aqueous sol in 1800 g of water was performed by dispersing 200 g of a light yellow transparent tin oxide aqueous sol with an apparatus, and then 0.8 g of isopropylamine was added thereto. By passing through a resin-filled column, an alkaline tin oxide aqueous sol (A) 2240 g
I got This sol (A) is stable and exhibits a colloidal color, but has a very high transparency, a specific gravity of 1.029 and a pH of 8.8.
The viscosity was 1.4 cp, the SnO ₂ content was 2.95% by weight, and the isopropylamine content was 0.036% by weight.

(2) Preparation of Sb ₂ O ₅ sol (B) According to the method proposed in JP-A-61-227918, a gel obtained by reaction with hydrochloric acid using sodium antimonate as a raw material is peptized with phosphoric acid. Is 1.142, pH 1.7
5, the viscosity 5.6cp, Sb ₂ O ₅ content of 13.4 wt%, Na ₂ O content 0.0017
% By weight, particle size of 5-15 mm
An aqueous Sb ₂ O ₅ sol (B) was obtained.

(3) Preparation of ZrO ₂ sol (C) A highly transparent and stable aqueous ZrO ₂ sol (C) was obtained by hydrolyzing an aqueous solution of zirconium oxychloride.
This sol has a specific gravity of 1.177, pH 3.85, viscosity of 5.6 cp, and ZrO ₂ content.
22.1% by weight, and the particle diameter determined by an electron microscope was 5 mm.

Example 1 modified SnO ₂ aqueous sol was made.

500 g of water was added to 420 g of the composite sol having a pH of 2.36 obtained in Reference Example 1 to obtain a diluted composite sol, which was added to 2240 g of the aqueous SnO ₂ sol (A) under vigorous stirring to obtain a stable low-concentration sol. 3160 g of a modified SnO ₂ aqueous sol was obtained. This sol has a specific gravity of 1.030, a pH of 4.65, a viscosity of 1.4 cp, a (WO ₃ + SnO ₂ ) / SnO ₂ weight ratio of 0.45, has a colloidal color but is highly transparent, and has a particle diameter of about 10 mm as measured by an electron microscope. microns, a specific surface area of 104m ² / g, in terms of particle size 8.7 millimicrons from the specific surface area was U.S. dynamic light scattering method particle diameter of 108 millimicrons by Coulter N ₄ device.

Next, 3160 g of the low-concentration modified SnO ₂ aqueous sol was concentrated by an ultrafiltration device with an ultrafiltration membrane having a molecular weight cutoff of 50,000 to obtain 517 g of high-concentration modified SnO ₂ aqueous sol. This sol has a specific gravity of 1.172, pH 4.20, viscosity of 2.8 cp, total SnO ₂ 13.67% by weight, WO ₃ 3.6% by weight, Na ₂ O 0.19% by weight, isopropylamine 0.14% by weight, and (WO ₃ + SnO ₂ ) / SnO ₂ weight ratio was 0.35. Although this sol had a colloidal color, it had high transparency and was stable at room temperature for 3 months or more. From the value of the WO ₃ content before and after the ultrafiltration, that about 20% of the original WO ₃ from the sol passes through the ultrafiltration membrane together with water was observed by ultrafiltration.

This high-concentration sol shows good dispersibility in methanol, and a stable mixed sol can be obtained by mixing with a normal anion-charged silica sol. The dried film of the high-concentration sol had a refractive index of 1.84.

Example 2 modified SnO ₂ aqueous sol was made.

Composite sol of pH2.36 obtained in Reference Example 1 (WO ₃ 5.96 wt%, SnO ₂ 1.17 wt%, WO ₃ + SnO ₂ 7.13 wt%) water 420 g 5
Of the aqueous tin sol (A) prepared in Reference Example 8 under vigorous stirring, and 0.6 g of isopropylamine was further added to obtain a stable low-concentration modified SnO. 4310 g of ₂ aqueous sol was obtained.
This sol has a specific gravity of 1.028, a pH of 6.97, a viscosity of 1.4 cP, (WO ₃ + S
The ratio by weight of nO ₂ ) / SnO _{2 was} 0.30, and the colloidal color was exhibited, but the transparency was high.

Next, 4310 g of this low-concentration modified SnO ₂ aqueous sol was concentrated by an ultrafiltration device of an ultrafiltration membrane having a molecular weight cutoff of 50,000,
410 g of a modified SnO ₂ aqueous sol with a high concentration was obtained. This sol has specific gravity
1.325, pH 6.35, viscosity 6.2cp, total SnO ₂ 25.4% by weight, WO ₃ 5.2
% By weight, (WO ₃ + SnO ₂ ) / SnO ₂ weight ratio 0.25, and isopropylamine 0.39% by weight. This sol had a colloidal color, but had high transparency, and was stable at room temperature for 3 months or more. About 15 wt% of the original WO ₃ from the value of the ultrafiltration before and after the WO ₃ were observed to pass through the ultrafiltration membrane together with water. This sol had good dispersibility in methanol, and could be stably mixed with ordinary anion-charged silica sol.

Example 3 modified SnO ₂ aqueous sol was made.

To 2,370 g of the tungsten oxide-tin oxide composite sol (IV) (WO ₃ + SnO ₂ 1.62% by weight) obtained in Reference Example 7, 8678 g of the alkaline tin oxide sol (A) (SnO ₂ 2.95% by weight) prepared in Reference Example 8 was strongly added. By adding under stirring, 11048 g of a stable low-concentration modified SnO ₂ sol was obtained. This sol has a specific gravity of 1.026, p
H7.50, viscosity 1.4 cp, (WO ₃ + SnO ₂ ) / SnO ₂ weight ratio 0.15, showing a colloidal color, but high transparency.

Then, 11048 g of this low-concentration modified SnO ₂ sol was concentrated by a filtration device of an ultrafiltration membrane having a molecular weight cutoff of 50,000 to obtain 940 g of high-concentration modified SnO ₂ aqueous sol. This sol has a specific gravity of 1.332, p
H7.10, viscosity 4.0 cp, total SnO ₂ 29.3 wt%, WO ₃ 1.85 wt%, (WO ₃ + SnO ₂ ) / SnO ₂ weight ratio 0.14, isopropylamine 0.38 wt%. Although this sol had a colloidal color, it had high transparency and was stable at room temperature for 3 months or more. About 5 wt% of the original WO ₃ from the value of the ultrafiltration before and after the WO ₃ were observed to pass through the ultrafiltration membrane together with water. This sol had good dispersibility in methanol, and could be stably mixed with ordinary anion-charged silica sol.

Example 4 modified SnO ₂ aqueous sol was made.

A stable low-concentration modified SnO _{2 having} a low concentration was added to 7410 g of the tungsten oxide-tin oxide composite sol (IV) obtained in Reference Example 7 by adding 8136 g of the aqueous sol (A) of alkaline tin oxide prepared in Reference Example 8 under vigorous stirring. 15546 g of an aqueous sol was obtained. This sol has a specific gravity of 1.0222, pH 6.42, viscosity of 1.4 cp, (WO ₃ + Sn
The weight ratio of O ₂ ) / SnO _{2 was} 0.50, indicating a colloidal color, but high transparency.

Next, 15546 g of this low-concentration modified SnO ₂ sol was concentrated by an ultrafiltration device of an ultrafiltration membrane having a molecular weight cut-off of 50,000 to obtain 1440 g of high-concentration modified SnO ₂ aqueous sol. This sol has a specific gravity of 1.2
56, pH 6.21, viscosity 6.8 cP, total SnO ₂ 20.7 wt%, WO ₃ 3.63 wt%, (WO ₃ + SnO ₂ ) / SnO ₂ weight ratio 0.46, and isopropylamine 0.35 wt%. Although this sol had a colloidal color, it had high transparency and was stable at room temperature for 3 months or more. About 10 wt% of the original WO ₃ from the value of the ultrafiltration before and after the WO ₃ were observed to pass through the ultrafiltration membrane together with water. This sol had good dispersibility in methanol, and could be stably mixed with ordinary anion-charged silica sol.

Example 5 modified SnO ₂ methanol sol was made.

The sol obtained by adding 1.8 g of isopropylamine and 1.8 g of tartaric acid to 510 g of the high-concentration modified SnO ₂ aqueous sol obtained in Example 1 was mixed with methanol 4 under reduced pressure in a rotary evaporator.
The water was distilled off while little by little was added to obtain 430 g of a modified SnO ₂ methanol sol in which the water of the aqueous sol was replaced with methanol. This sol has a specific gravity of 0.974, a pH of 6.29 (an equal weight mixture with water), a viscosity of 3.0 cp, a total SnO _{2 of} 16.23% by weight, a WO
₃ 4.27 wt%, moisture 2.9 wt%, isopropylamine 0.58
It was 5% by weight and tartaric acid 0.419% by weight. This sol contained trace amounts of sediment, but had a colloidal color and high transparency. Even after leaving at room temperature for 3 months, the amount of sediment at the beginning was not increased, and was stable.

Example 6 A modified SnO ₆ methanol sol was made.

Tartaric acid was added to 410 g of the high concentration modified SnO ₂ aqueous sol of Example 2.
3 g, diisobutylamine 7.4 g, defoamer (manufactured by San Nopco)
SN Deformer 483) 410 g of a modified SnO ₂ methanol sol in which the water of the aqueous sol was replaced with methanol by adding 1 drop and then distilling off water while gradually adding methanol 6 under reduced pressure using a rotary evaporator. I got
This sol has a specific gravity of 1.096, pH 8.34 (equiweight mixture with water), viscosity of 4.5cp, total SnO ₂ 25.4% by weight, WO ₃ 5.2% by weight, W
30.6% by weight of O ₃ + SnO ₂ , 2.3% by weight of water, 0.35% by weight of isopropylamine, 1.62% by weight of diisobutylamine, and 0.56% by weight of tartaric acid. In addition, about 10% by weight of the amine was lost by volatilization when the methanol was replaced.

This sol had a colloidal color, was highly transparent, and was stable without any abnormalities such as formation of sediment, turbidity and thickening even after being left at room temperature for 3 months.

 The dried product of this sol had a refractive index of 1.84.

Example 7 A modified SnO ₂ methanol sol was made.

To 940 g of the high-concentration modified SnO ₂ aqueous sol of Example 3
6g, 8.5g diisobutylamine, defoamer (manufactured by San Nopco)
SN deformer 483) 950 g of a modified SnO ₂ methanol sol in which the water of the aqueous sol was replaced with methanol by adding 1 drop and then distilling off water while gradually adding methanol 12 under reduced pressure using a rotary evaporator. I got
This sol had a specific gravity of 1.120, a pH of 7.10 (equivalent weight mixture with water), a viscosity of 7.5 cp, a total SnO _{2 of} 29.0 wt%, a WO _{3 of} 1.83 wt%,
WO ₃ + SnO ₂ 30.8% by weight, moisture 3.0% by weight, isopropylamine 0.34% by weight, diisobutylamine 0.82% by weight, and tartar powder 0.59% by weight. In addition, about 10% by weight of the amine was lost by volatilization when the methanol was replaced. This sol had a colloidal color, was highly transparent, and was stable without any formation of sediment, turbidity, thickening, etc. after standing at room temperature for 3 months. The dried product of this sol had a refractive index of 1.83.

Example 8 modified SnO ₂ methanol sol was made.

Tartar powder was added to 1440 g of the high-concentration modified SnO ₂ aqueous sol of Example 4.
After adding 7.0 g, 12.0 g of diisobutylamine and 2 drops of an antifoaming agent (SN Deformer 483 manufactured by San Nopco), water was distilled off while adding methanol 21 little by little under reduced pressure using a rotary evaporator. 1160 g of a modified SnO ₂ methanol sol in which water in the aqueous sol was replaced with methanol was obtained. This sol has a specific gravity of 1.118, a pH of 6.82 (equivalent mixture with water), a viscosity of 8.5 cp, a total SnO _{2 of} 25.7% by weight, a WO _{3 of} 4.5% by weight, a WO ₃ + SnO _{2 of} 30.2% by weight, a water of 2.5% by weight, and an isopropylamine. 0.37% by weight, diisobutylamine 0.93% by weight,
The tartaric powder was 0.60% by weight. In addition, about 10% by weight of the amine was lost by volatilization when the methanol was replaced. This sol had a colloidal color, was highly transparent, and was stable without any formation of sediment, turbidity, thickening, etc. after standing at room temperature for 3 months. The dried product of this sol had a refractive index of 1.84.

Example 9 modified Sb ₂ O ₅ aqueous sol was made.

The Sb ₂ O ₅ aqueous sol (B) 1036g of Reference Example 8, obtained in Reference Example 1 was added to the strong stirring composite sol 590g of PH2.36, stable by addition of further n- propylamine 7.0g 1626 g of a low-concentration modified Sb ₂ O ₅ aqueous sol was obtained.

Then, the low-concentration sol was concentrated with an ultrafiltration membrane having a molecular weight cut-off of 50,000 to obtain a high-concentration modified Sb ₂ O ₅ aqueous sol 890.
g was obtained. This sol has a specific gravity of 1.214, pH 2.81, and a viscosity of 2.2c.
p, Sb ₂ O ₅ 15.7% by weight, WO ₃ 3.52 wt%, SnO ₂ 0.84 wt%, Na ₂ O0.18 wt%, n-propylamine 0.72% by weight,
The weight ratio (WO ₃ + SnO ₂ ) / Sb ₂ O ₅ was 0.28. This sol has a colloidal color, but is highly transparent and has a room temperature of 3
It has been stable for more than a month. This sol showed good dispersibility in methanol and showed a refractive index of the dried film of 1.74.

Example 10 modified Sb ₂ O ₅ methanol sol was made.

250 g of the high-concentration modified Sb ₂ O ₅ aqueous sol obtained in Example 9
Then, in a rotary evaporator, by adding 2.5 methanol under reduced pressure while distilling water, modified aqueous Sb ₂ O ₅ methanol sol 3 in which water in the aqueous sol was replaced with methanol.
35 g were obtained. This sol had a specific gravity of 0.946, (mixture with water in an equal weight) PH3.69, viscosity 12.8cp, Sb ₂ O ₅ 11.8 wt%, WO ₃ 2.7
% By weight, SnO ₂ 0.62% by weight, moisture 6.1% by weight, and n-propylamine 0.52% by weight. This sol had a colloidal color, but was transparent and stable at room temperature for 3 months or more.

Example 11 modified ZrO ₂ aqueous sol was made.

1300 g of water was added to 200 g of the aqueous ZrO ₂ sol (C) of Reference Example 8 to prepare a diluted ZrO ₂ aqueous sol. Separately, 200 g of water was added to 230 g of the pH 2.36 composite sol obtained in Reference Example 1 to obtain a diluted composite sol.

Next, 430 g of the diluted composite sol was added to 1500 g of the diluted ZrO ₂ aqueous sol under vigorous stirring.
By adding 3.0 g, 1930 g of a stable low-concentration modified ZrO ₂ aqueous sol was obtained.

Further, this low-concentration denatured ZrO ₂ sol is concentrated under reduced pressure in a rotary evaporator to obtain a high-concentration denatured ZrO ₂ sol.
315 g of aqueous ZrO ₂ sol was obtained. This sol has a specific gravity of 1.184, pH
7.05, viscosity 2.4cp, ZrO ₂ 14.0% by weight, WO ₃ 4.35% by weight, Sn
O ₂ 0.85% by weight, isopropylamine 0.95% by weight, (WO ₃
+ SnO ₂ ) / ZrO ₂ weight ratio was 0.37. This sol had a colloidal color and was slightly transparent, but was stable at room temperature for 3 months or more. This sol showed good dispersibility in methanol, and could be stably mixed with ordinary anion-charged silica sol. The refractive index of the dried film of this sol was 1.95.

Test Example 1 In this test example, a hard coat agent was prepared using the modified metal oxide sol of the present invention obtained in Examples 1 to 11, and the performance of the hard coat film was tested.

As the binder, methyltrimethoxysilane 150
400 parts by weight of isopropanol was added to 0.1 parts by weight, and
12 parts by weight of N hydrochloric acid and 50 parts by weight of water are added dropwise, and the mixture is further stirred for 10 hours, and then left at room temperature for 16 hours.Then, the pH is adjusted to almost neutral by adding 0.6 g of isopropylamine. A hydrolyzed liquid of methyltrimethoxysilane was used.

11 kinds of hard coat agents, 612 g of the binder,
300 g of any of the high-concentration modified metal oxide aqueous sol and the methanol sol obtained in Examples 1 to 11, 0.2 g of a commercially available silicone surfactant, and 0.
1 g and made by stirring for 4 hours.

As a substrate, a lens (trade name, CR-39) of a diethylene glycol bisalkali carbonate polymer which was well washed after alkali treatment was prepared.

Next, the lens was immersed in the hard coat agent, taken out, left at room temperature, and then cured at 120 ° C. for 2 hours to form a hard coat film on the lens. This coating adhered strongly to the lens, and had high refractive index, adhesion and transparency.

In Comparative Examples 1 and 2 below, examples of poorly stable tungsten oxide-tin oxide composite sols, and Comparative Example 3 examples of poorly stable modified ZrO ₂ aqueous sols, and Comparative Example 4 further includes: An example in which a hard coat film is formed using the unmodified ZrO ₂ aqueous sol (C) of Reference Example 8 is shown.

Comparative Example 1 An aqueous solution of sodium tungstate having a WO ₃ content of 7.16% by weight was passed through a column filled with a hydrogen-type cation exchange resin to obtain 1420 g of an aqueous solution of tungstic acid. This aqueous solution had a specific gravity of 1.068, a pH of 1.60, a viscosity of 2.0 cp, a WO ₃ content of 6.8% by weight, and a Na ₂ O content of 0.04% by weight.

An aqueous sol was obtained by adding 5 g of a separately prepared aqueous solution of sodium stannate having a SnO ₂ content of 15.0 wt% and a Na ₂ O content of 6.2 wt% to 1420 g of the aqueous solution of tungstic acid with vigorous stirring. Gelled after about 1 hour. The sol immediately after the production has a specific gravity of 1.068, pH1.62, WO ₃ content 6.78
Weight%, SnO ₂ content 0.053% by weight, Na ₂ O content 0.062% by weight, WO ₃ / SnO ₂ weight ratio is 128, Na ₂ O / WO ₃ + SnO ₂ molar ratio is
0.034 is calculated.

Comparative Example 2 The aqueous sol 210 having a specific gravity of 1.062 and a pH of 1.53 obtained in Reference Example 2
0 g and 300 g of an aqueous solution of sodium stannate having a SnO ₂ content of 15.0 wt% and a Na ₂ O content of 6.2 wt% were mixed with vigorous stirring to obtain an aqueous sol. This sol has a slightly colloidal color, is almost colorless and transparent, and has a specific gravity of 1.079, pH 8.02,
Viscosity 1.5 cp, WO ₃ content of 4.98 wt%, SnO ₂ content of 2.85% by weight,
The Na ₂ O content was 0.81% by weight.

Next, when this sol was concentrated under reduced pressure in a rotary evaporator, the sol became cloudy with the progress of concentration.

Separately, when the pH was lowered by adding a hydrogen-type cation exchange resin to the above sol under stirring, when the pH reached about 5, the sol was thickened and a stable sol was not obtained.

According to the contents of WO ₃ , SnO ₂ and Na ₂ O, this sol is W
The O ₃ / SnO ₂ weight ratio is 1.75, and the Na ₂ O / WO ₃ + SnO ₂ molar ratio is 0.32.

Comparative Example 3 Water (1300) was added to 200 g of the aqueous ZrO ₂ sol (C) obtained in Reference Example 8.
g was added to obtain a diluted sol, to which 10 g of the pH 2.36 composite sol obtained in Reference Example 1 was added under vigorous stirring. As a result, the mixture became cloudy and thickened, and a stable sol was obtained. Did not. Further, when this mixture was added to a usual anion-charged silica sol, remarkable gelation occurred. In this mixture, the (WO ₃ + SnO ₂ ) / ZrO ₂ weight ratio was 0.016, indicating that the amount of added composite sol was insufficient.

Comparative Example 4 In the performance test of the hard coat film of Test Example 1,
A hard coat film was formed in the same manner except that the aqueous ZrO ₂ sol (C) according to Reference Example 8 was used instead of the modified metal oxide sol, but the film had a high refractive index but showed cloudiness. Further, all of the transparency, adhesion and weather resistance were insufficient.

(Effect of the Invention) The sol of the colloidal particles of the tungsten oxide-tin oxide composite obtained by the present invention is colorless and transparent, and the dried coating film has a high refractive index of about 1.8 to 1.9, and has a bonding strength. , Hardness, water resistance and adhesion. Further, the antistatic property, heat resistance, abrasion resistance and the like are good. The sol of the trivalent to pentavalent metal oxide colloidal particles surface-modified with the tungsten oxide-tin oxide composite colloidal particles is also colorless and transparent, and the dried coating film has a refractive index of about 1.7 to 2.2, Again, it exhibits the same excellent performance as the sol of the colloidal particles of the tungsten oxide-tin oxide composite.

These sols are stable at about pH 1-9,
It can also provide sufficient stability to be supplied as an industrial product.

These sols have good miscibility with sols composed of other negatively charged colloidal particles because the colloidal particles are negatively charged, such as silica sol, antimony pentoxide sol, anionic or nonionic. Surfactants, aqueous solutions of polyvinyl alcohol and the like, anionic or nonionic resin emulsions, aqueous glasses, and aqueous dispersions of aluminum phosphate and the like.

The sol of the present invention having such properties is particularly useful as a component for improving a refractive index, a coloring property, a chemical resistance, a water resistance, a weather resistance, a wear resistance, etc. for forming a hard coat film on a plastic lens. However, it can be used for various other uses.

By applying these sols to the surface of organic fibers, fiber contact products, paper, etc., the flame retardancy, surface slip resistance, antistatic property, dyeing property, etc. of these materials can be improved. These sols also contain ceramic fibers,
It can be used as a binder for glass fibers, ceramics and the like. Furthermore, by mixing and using in various paints, various adhesives, etc., the water resistance of those cured coating films,
Chemical resistance, weather resistance, abrasion resistance, flame resistance and the like can be improved. In addition, these sols can be generally used as surface treatment agents for metal materials, ceramic materials, glass materials, plastic materials, and the like. Further, it is also useful as a catalyst component.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-151038 (JP, A) JP-A-3-172369 (JP, A) JP-A-4-4273 (JP, A) 21213 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C01G 1/02 B01J 13/00 C03C 17/23 C09D 1/00

Claims (2)

(57) [Claims] 1. The method according to claim 1, wherein said colloidal particles of metal oxide having a valence of 3, 4 or 5 having a particle diameter of 4 to 50 millimicrons are used as nuclei, and the surface thereof has a WO ₃ / SnO ₂ weight ratio of 0.5 to 100. Diameter 2
A modified metal oxide sol comprising modified metal oxide colloid particles having a particle diameter of 4.5 to 60 millimicrons formed by being coated with tungsten oxide-tin oxide composite colloid particles having a particle size of ７7 millimicrons, The modified metal oxide colloid particles have a ratio of 2 to 100 parts by weight of a tungsten oxide-tin oxide complex with respect to 100 parts by weight of a metal oxide having a valence of 3, 4 or 5; 2 to 2 in the above sol as all metal oxides
The above modified metal oxide sol containing 50% by weight. 2. A sol having a valence of 3, 4, or 5 having a particle diameter of 4 to 50 millimicrons, 100 parts by weight of a metal oxide contained in the sol, and particles of 2 to 7 millimicrons. A tungsten oxide-tin oxide composite sol having a diameter and a WO ₃ / SnO ₂ weight ratio of 0.5 to 100 is mixed in a ratio of 2 to 100 parts by weight as a composite contained in the sol. Item 10. A method for producing a modified metal oxide sol according to Item 1.