JPH062223B2 - Tungsten oxide-tin monoxide composite sol and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a stable tungsten oxide-tin oxide composite sol and a method for producing the same. The tungsten oxide-tin oxide composite sol of the present invention is a treatment agent for fibers and papers; a surface treatment agent for metals, glass, plastics, etc .; a paint binder; a flame retardant aid for fibers, plastics, etc .; ceramics fibers, glass. It is used as a binder for fibers, ceramics, etc .; an antistatic agent for paper, plastics, etc .; a refractive index improver for a hard coat agent, a hardness improver, etc.

(Prior Art) A stable sol containing only tungsten oxide is not known yet, but WO ₃ : SiO ₂ : M ₂ O (where M represents an alkali metal atom or an ammonium group) obtained by adding a silicate. ) A sol having a molar ratio of 4 to 15: 2 to 5: 1 is proposed in JP-A-54-52686.

Also, Japanese Patent Publication No. 40-40119 discloses that the molar ratio of Si: Sn is 2
A silicic acid-stannic acid composite sol of ~ 1000: 1 has been proposed.

(Problems to be Solved by the Invention) The sol of tungsten oxide described in JP-A-54-52686 described above is obtained by subjecting an aqueous solution of tungstate to a decationization treatment to obtain an aqueous solution of tungstic acid containing a silicate. , But it is stable only in strong acidity, and its usefulness is not wide-ranging. For example, even if it is used as a flame retardant aid, its flame retardancy improving effect is small, and when it is used as a hard coat agent, the refractive index improving effect of the coating film is small.

The silicic acid-stannic acid composite sol described in JP-B-50-40119 is obtained by decationizing a mixed aqueous solution of alkali silicate and alkali stannate. Not suitable for.

The present invention aims to provide a novel tungsten oxide-tin oxide composite sol suitable for various applications.

(Means for Solving the Problems) The stable tungsten oxide-tin oxide composite sol of the present invention is a composite colloidal particle of tungsten oxide (WO ₃ ) and tin oxide (SnO ₂ ) and an alkali metal, ammonium or amine positive. And the weight ratio of WO ₃ and SnO ₂ contained in this sol is ₂ to 100 as WO ₃ / SnO 2.
And the amount of cation of alkali metal, ammonium or amine contained in this sol is M ₂ O / WO ₃ + SnO ₂
(However, M represents an alkali metal atom, an ammonium group or an amine molecule.) The molar ratio is 0.02 to 0.7.

Stable tungsten oxide of the present invention - tin composite sol oxide, preferably, a tungstic acid aqueous solution obtained by treating an aqueous solution of tungstate with hydrogen-type cation exchanger, an aqueous solution of stannate WO ₃ / SnO ₂ in a ratio of ₂ to 100, and M of alkali metal hydroxide, ammonium hydroxide or amine in the mixture and WO _{3 of} these tungstic acids and SnO ₂ of stannate.
₂ O / WO ₃ + SnO ₂ (where M is the same as above) molar ratio
It is obtained by a method characterized by adjusting to 0.02-0.7.

The composite colloidal particles of WO ₃ and SnO ₂ contained in the tungsten oxide-tin oxide composite sol of the present invention have a particle size of about 7 mm or less, usually 5 to 2 mm, as observed by an electron microscope. The dispersion medium for the colloidal particles of this sol may be either water or a hydrophilic organic solvent.
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. Kinds; glycols such as ethyl cellosolve, butyl cellosolve, ethylene glycol and the like can be mentioned.

Examples of the alkali metal, ammonium or amine contained in the sol of the present invention include Li, Na, K, Rb, Cs, NH ₄ , ethylamine, triethylamine, isopropylamine,
Examples thereof include alkylamines such as n-propylamine; aralkylamines such as benzylamine; alicyclic amines such as piperidine; and alkanolamines such as monoethanolamine and triethanolamine. These may be contained as a mixture of two or more kinds.

A preferred sol of the present invention contains WO ₃ and SnO ₂ in a WO ₃ / SnO ₂ weight ratio of 2 to 100, and these WO ₃ and S
The above-mentioned alkali metal, ammonium, amine and the like are contained in a ratio of 0.02 to 0.7 in terms of M ₂ O / WO ₃ + SnO ₂ molar ratio with respect to the total of nO ₂ .

The total concentration of WO ₃ and SnO ₂ contained in the sol of the present invention is usually 40% by weight or less, practically preferably 2% by weight or more, and preferably 10 to 30% by weight.

The sol of the present invention may contain other optional components as long as the object of the present invention is achieved. In particular, when an oxycarboxylic acid is contained in an amount of about 30% by weight or less based on the total amount of WO ₃ and SnO ₂ , a further improved sol can be obtained. Examples of the oxycarboxylic acid used include lactic acid, tartaric acid, citric acid, gluconic acid, malic acid, glycolic acid and the like.

A preferred sol of the present invention exhibits a pH of 1-9 and is colorless,
It is a transparent or almost transparent liquid. It is stable for 3 months or longer at room temperature and stable for 1 month or longer even at 60 ° C., no precipitate is formed in the sol, and the sol does not thicken or gel. .

Examples of the tungstates and stannates used in the production of the sol of the present invention include the above-mentioned tungstates of alkali metals, ammonium and amines, stannates and the like. In particular, sodium tungstate Na ₂ WO ₄ .2H ₂ O and sodium stannate Na ₂ SnO ₃ .3H ₂ O are preferable. Also.
The thing which melt | dissolved tungsten oxide, tungstic acid, stannic acid, etc. in the aqueous solution of an alkali metal hydroxide can also be used.

The hydrogen-type cation exchanger used may be an ordinary one, and a hydrogen-type cation exchange resin can be conveniently obtained as a commercial product. The alkali metal hydroxide, ammonium hydroxide, amine and the like used may be commercial products. Examples of alkali metal hydroxides include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like. Examples of amines include those exemplified above.

The aqueous solution of tungstic acid used for producing the sol of the present invention can be easily obtained by treating the above aqueous solution of tungstate with the above cation exchange resin at a temperature of 100 ° C. or lower, preferably room temperature to 60 ° C. or so. . Since this aqueous solution of tungstic acid has colloidal properties and therefore has a property of easily gelling, it is convenient to use it before gelling. The aqueous solution of tungstate used for preparing the aqueous solution of tungstic acid is WO
₃ is preferably 0.1 to 15% by weight, and even if an aqueous solution of tungstic acid is used, its WO ₃ concentration is 0.1 to
About 15% by weight is preferable.

The aqueous solution of stannate used for producing the sol of the present invention preferably has a SnO ₂ concentration of about 0.1 to 30% by weight, but may have a higher concentration. In some cases, solid stannate can be used.

The sol according to the present invention is produced by mixing the aqueous solution of tungstic acid with the aqueous solution of stannate. This mixing is preferably performed at room temperature to 100 ° C., preferably room temperature to 60 ° C., with sufficient stirring. The liquid amount to be mixed is preferably a WO ₃ / SnO ₂ weight ratio of about 2 to 100. Due to this mixing, M ₂ O
(M is the same as above) in a molar ratio of about 0.015 to 0.44 with respect to the sum of WO ₃ and SnO ₂ . A preferred sol according to the present invention has a M ₂ O / WO ₃ + SnO ₂ molar ratio in this liquid of 0.02 to
Since it is 0.7, the M ₂ O / WO ₃ + SnO ₂ molar ratio in the liquid obtained by the above mixing is adjusted in some cases.
As a method for increasing the above molar ratio in the liquid obtained by the above mixing, it can also be carried out by adding an alkali metal oxide, ammonium hydroxide, amine or the like to this mixed liquid. After treatment with a cation exchange resin, it can be carried out by adding alkali metal hydroxide, ammonium hydroxide, amine, etc. so that the molar ratio of M ₂ O / WO ₃ + SnO ₂ is 0.02 to 0.7. it can.

By the above mixing, or by the above mixing and adjusting the M ₂ O / WO ₃ + SnO ₂ molar ratio, a stable tungsten oxide-tin oxide composite aqueous sol according to the present invention is obtained. When the concentration of the aqueous sol is low, the concentration of the sol can be increased, if desired, by a conventional concentration method such as an evaporation method or an ultrafiltration method. In particular, the ultrafiltration method is preferable. Even in this concentration, the temperature of the sol is about 100 ° C.
It is particularly preferable to keep the temperature below 60 ° C.

A hydrophilic organic solvent sol called an organosol is obtained by substituting the hydrophilic organic solvent for water in the aqueous sol. The replacement of the water with the hydrophilic organic solvent can be easily carried out by an ordinary method such as a distillation replacement method or an ultrafiltration method. When the pH of the aqueous sol is high, it is preferable to add the oxycarboxylic acid to the aqueous sol before or at the same time as the above substitution. Regardless of the presence or absence of this oxycarboxylic acid, the sol temperature is about 10 even when the medium of the sol is replaced.
It is preferable to keep it at 0 ° C or lower, particularly 60 ° C or lower.

(Function) 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 are contained in a WO ₃ / SnO ₂ weight ratio of 2 to 100.
It has been found that a stable sol can be obtained by mixing with. Stability of this sol, the colloidal particles of tin oxide and tungsten oxide colloidal particles produced by the above mixing or composite colloidal particles of tungsten oxide and tin oxide by the binding of polyanions, alkali metal introduced by stannate, It is considered that this is because cations such as ammonium and amine were bound to form stable colloidal particles.

However, if the weight ratio of WO ₃ / SnO ₂ in the obtained sol is less than 2, it is unstable when the sol is acidic, and if the weight ratio exceeds 100, the sol also shows no stability. Even when the amount of cations such as alkali metals, ammonium and amine contained in the sol is less than 0.02 as the M ₂ O / WO ₃ + SnO ₂ molar ratio, such a sol has poor stability, and However, if this molar ratio exceeds 0.7, the water resistance of the dry coating film obtained using such a sol is low, which is not preferable in practice. The oxycarboxylic acid added when forming 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 WO ₃ and SnO in the sol.
_If it is more than 30% by weight based on the total of ₂ , the water resistance of the dry coating film obtained by using such a sol will be lowered. The pH of the sol changes depending on the amount of alkali metal, ammonium, amine, oxycarboxylic acid, etc. in the sol. When the pH of the sol is 1 or less, the sol is unstable, and when the pH is 9 or more, the composite colloidal particles of tungsten oxide and tin oxide are easily dissolved in the liquid. When the total concentration of WO ₃ and SnO _{2 in} the sol is as high as 40% by weight or more, the sol also has poor stability. If this concentration is too low, it is impractical, and the preferable concentration for industrial products is 10 to 30% by weight.

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

In addition, the WO ₃ concentration of the aqueous solution of tungstic acid used is
If it is less than 0.1% by weight, the concentration of the obtained sol is lowered and a large amount of water needs to be removed at the time of concentration, which is not efficient. When the WO ₃ concentration of this aqueous solution of tungstic acid is as high as 15% by weight or more in the reaction, such an aqueous solution has poor stability and is likely to be difficult to handle.

When the ultrafiltration method is used as the concentration method, the polyanion of tungsten oxide, ultrafine particles, etc. coexisting in the sol pass through the ultrafiltration membrane together with water, which causes the destabilization of the sol. These polyanions and ultrafine particles can be removed from the sol.

In the aqueous sol of the present invention, at a temperature of 100 ° C. or higher, since the composite colloidal particles of tungsten oxide and tin oxide in the sol are hydrolyzed and dissolved, or these oxides are easily precipitated, the above cation exchange is performed. Maintained at 100 ° C or lower during treatment with resin, mixing, concentration, etc. As a safe temperature at which such a change does not occur, 60 ° C. or lower is preferable.

(Example) Example 1 By dissolving 550 g of sodium tungstate Na ₂ WO ₄ .2H ₂ O (first-grade reagent) in 4850 g of water, 5400 g of an aqueous solution of sodium tungstate was obtained. This aqueous solution had a specific gravity of 1.086, a pH of 9.79 and a WO ₃ content of 7.16% by weight.

Next, the entire amount of the above aqueous solution is passed through a column packed with a hydrogen type cation exchange resin (Amberlite 120B, manufactured by Organo) to give an aqueous solution 5690 of tungstic acid.
g was obtained. 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 wt% and a Na ₂ O content of 0.04 wt%.
And was a yellow transparent liquid. The aqueous solution changed into a gel after 1 hour at room temperature.

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

Then, an aqueous solution of tungstic acid 569 immediately after the above production
By adding 505 g of the aqueous solution of sodium stannate to 0 g under strong stirring at room temperature, a tungsten oxide-tin oxide composite aqueous sol of the present invention was obtained. This sol had a slight colloidal color, but was almost colorless and transparent. And specific gravity 1.073, pH 5.03, viscosity 1.5 cp, WO
₃ content 6.25% by weight, SnO ₂ content 1.22% by weight, Na ₂ O content
The content was 0.54% by weight, and the colloidal particle diameter by electron microscope observation was about 5 millimicrons. Further, this sol had stability for 3 months or more when it was left at room temperature under a closed condition. From the above values, the value of the weight ratio WO ₃ / SnO ₂ of WO ₃ and SnO ₂ in this sol is
The value of 5.12 and Na ₂ O / WO ₃ + SnO ₂ molar ratio was calculated to be 0.25.

Example 2 By passing 3100 g of the aqueous sol obtained in Example 1 through a column packed with a hydrogen type cation exchange resin, a specific gravity of 1.06 was obtained.
2, pH 1.53, viscosity 1.5 cp, WO ₃ content 5.69% by weight, SnO
An aqueous sol of the present invention having a ₂ content of 1.11% by weight and a Na ₂ O content of 0.04% by weight was obtained. From the above values, Na ₂ O / WO ₃ + S of this sol
The nO ₂ molar ratio is calculated to be 0.02.

Next, 3400 g of this sol having a pH of 1.53 and 3095 g of the sol having a pH of 5.03 obtained in Example 1 were mixed at room temperature to obtain an aqueous sol of the present invention. The sol obtained here had a slight colloidal color, but was almost colorless and transparent, with a specific gravity of 1.068, a pH of 2.36, a viscosity of 1.5 cp, and a WO ₃ content of 5.
The content was 96% by weight, the SnO ₂ content was 1.17% by weight, the Na ₂ O content was 0.28% by weight, and the colloidal particle size was about 5 millimicron as observed by an electron microscope. It was stable for more than 3 months in a test of leaving it at room temperature. When calculated from the above values, the WO ₃ / SnO ₂ weight ratio was 5.12, and the Na ₂ O / WO ₃ + SnO ₂ molar ratio was 0.135.

Next, when 6495 g of this sol having a pH of 2.36 was concentrated by an ultrafiltration method, 1840 g of a high-concentration sol was obtained. This sol also had a slight colloidal color, but was almost colorless and transparent, with a specific gravity of 1.212, a pH of 2.34 and a viscosity of 2.5.
cp, WO ₃ content 17.1% by weight, SnO ₂ content 3.93% by weight, Na ₂ O
The content was 0.88% by weight, the colloidal particle size by electron microscope observation was about 5 mm, and the particle size by dynamic light scattering method (N ₄ apparatus manufactured by Coulter Co., USA) was 90 mm. The WO ₃ / SnO ₂ weight ratio of this high-concentration sol was 4.35, N
The a ₂ O / WO ₃ + SnO ₂ molar ratio is calculated to be 0.14. Further, the ultrafiltration reduces about 20% of WO _{3 in} the trace before filtration. This reduction is due to WO ₃ passing through the ultrafiltration membrane.
Of polyanions or ultrafine particles were present in the sol before filtration.

Furthermore, when the above-mentioned high-concentration sol was tested, the dispersion in methanol was good, and it had stability at room temperature for 3 months or more. The light refractive index of the dried sol was 1.84.

Example 3 6135 g of an aqueous solution of tungstic acid was prepared by passing 5400 g of an aqueous solution of sodium tungstate having a WO ₃ content of 7.16% by weight through a column packed with a hydrogen type cation exchange resin.
Got This aqueous solution has a specific gravity of 1.062, pH of 1.48 and viscosity.
2.5 cp, WO ₃ content 6.16% by weight, Na ₂ O content 0.03% by weight
Met. Therefore, the Na ₂ O / WO ₃ molar ratio is calculated to be 0.018.

Then, an aqueous solution of tungstic acid 613 immediately after the above production
To 5 g, 765 g of an aqueous solution of sodium stannate (SnO ₂ content 15.0% by weight, Na ₂ O content 62% by weight) was added under strong stirring at room temperature to obtain 6900 g of the aqueous sol of the present invention. This sol has a specific gravity of 1.073, a pH of 6.72 and a viscosity of 1.5c.
p, WO ₃ content 5.60% by weight, SnO ₂ content 1.67% by weight, Na ₂ O
The content was 0.71% by weight. By calculation, the WO ₃ / SnO ₂ weight ratio is 3.35 and the Na ₂ O / WO ₃ + SnO ₂ molar ratio is 0.33.

Next, the above sol is rotoevaporated.
When concentrated under reduced pressure, 1610 g of high-concentration aqueous sol was obtained. This high-concentration sol was slightly colored in color, but almost colorless and transparent, with a specific gravity of 1.385, pH of 6.68,
The viscosity was 2.6 cp, the WO ₃ content was 24.0% by weight, the SnO ₂ content was 7.14% by weight, the Na ₂ O content was 3.06% by weight, and the colloidal particle diameter by an electron microscope was about 5 mm. It was stable for more than 3 months even at room temperature.

Example 4 To 3250 g of the aqueous sol having a specific gravity of 1.068 and pH of 2.36 obtained in Example 2, 22 g of n-propylamine and 19 g of tartaric acid were added with stirring to obtain an aqueous sol. This sol has a specific gravity of 1.067, a pH of 3.82, a viscosity of 1.5 cp, and a WO ₃ content.
5.88 wt%, SnO ₂ content 1.16 wt%, Na ₂ O content 0.28
% By weight, the above amine content is 0.67% by weight, tartaric acid content is 0.5
It was 8% 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
Is.

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 slight colloidal color, but was almost colorless and transparent, with a specific gravity of 1.282, a pH of 3.68 and a viscosity of 2.3c.
p, WO ₃ content 1.99% by weight, SnO ₂ content 3.93% by weight, Na ₂ O
The content was 0.95% by weight, the amine content was 2.27% by weight, and the tartaric acid content was 1.97% by weight. This sol had good dispersibility in methanol, and had stability for standing at room temperature for 3 months or more.

Example 5 215 g of an aqueous sol having a specific gravity of 1.212 and a pH of 2.34 obtained in Example 2 was charged into a rotary evaporator, to which methanol 3 was continuously added little by little under reduced pressure.
By distilling off the medium of the sol, 376 g of methanol sol in which water in the aqueous sol was replaced with methanol was obtained.
This sol had a slight colloidal color, but was almost colorless and transparent, with a specific gravity of 0.932, a pH of 3.46 (equal weight mixture of this sol and water), a viscosity of 6.2 cp, and a WO ₃ content of 9.78. % By weight, a SnO ₂ content of 2.25% by weight, and a water content of 7.5% by weight.
This sol produced a very small amount of sediment on standing,
The amount was stable and did not increase even if the standing period was extended.

Example 6 For 300 g of the high-concentration aqueous sol obtained in Example 4, 350 g of methanol sol was obtained by replacing the medium water with methanol in the same manner as in Example 5. This sol had a slight colloidal color, but was almost colorless and transparent, with a specific gravity of 0.978, pH 5.28 (equal weight mixture of this sol and water), viscosity 4.0 cp, and WO ₃ content 17.1% by weight. , SnO ₂ content
3.37% by weight, Na ₂ O content 0.81% by weight, n-propylamine content 1.94% by weight, tartaric acid content 1.69% by weight, water content
The content was 3.5% by weight, and no sediment was formed at 3 months when left at room temperature, which was stable.

Comparative Example 1 1420 g of an aqueous solution of tungstic acid was obtained by passing an aqueous solution of sodium tungstate having a WO ₃ content of 7.16% by weight through a column packed with a hydrogen type cation exchange resin. This aqueous solution has a specific gravity of 1.068, pH of 1.60, viscosity of 2.0 cp, and WO
_{The 3} content was 6.8 wt% and the Na ₂ O content was 0.04 wt%.

An aqueous sol was obtained by adding separately prepared 5 g of an aqueous solution of sodium stannate having an SnO ₂ content of 15.0% by weight and a Na ₂ O content of 6.2% by weight to 1420 g of the above tungstic acid aqueous solution with vigorous stirring. However, this sol gelled after about 1 hour. Immediately after production, this sol has a specific gravity of 1.068, pH of 1.62,
WO ₃ content 6.78% by weight, SnO ₂ content 0.053% by weight, Na ₂ O
The content is 0.062% by weight, and the WO ₃ / SnO ₂ weight ratio is 12
8. The Na ₂ O / WO ₃ + SnO ₂ molar ratio is calculated to be 0.034.

Comparative Example 2 2100 g of an aqueous sol having a specific gravity of 1.062 and a pH of 1.53 obtained in Example 2 and 300 g of an aqueous sodium stannate solution having a SnO ₂ content of 15.0 wt% and a Na ₂ O content of 6.2 wt% were prepared. An aqueous sol was obtained by mixing with vigorous stirring. This sol has a slight colloidal color, is almost colorless and transparent, and has a specific gravity of 1.0.
79, pH 8.02, viscosity 1.5 cp, WO ₃ content 4.98% by weight, S
The nO ₂ content was 2.85% by weight and the Na ₂ O content was 0.81% by weight.

Next, when this sol was concentrated under reduced pressure in a rotary evaporator, it became cloudy as the concentration proceeded.

Separately, the pH was lowered by adding a hydrogen type cation exchange resin to the above sol with stirring. When the pH reached about 5, the sol thickened and a stable sol could not be obtained.

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

(Effects of the Invention) The novel tungsten oxide-tin oxide composite sol of the present invention is stable for a long period of time even at a high concentration and has various useful properties. The colloidal particles of this sol are composite colloidal particles produced by combining the colloidal particles of tungsten oxide and the colloidal particles of tin oxide, which are stabilized by cations such as alkali metals, ammonium and amines, and have a particle diameter of about 7 mm. It is less than micron and is negatively charged. The sol is stable in the pH range of about 1 to 9 and almost colorless and transparent.

This sol has good miscibility with other sol composed of negatively charged colloidal particles because the colloidal particles are negatively charged. For example, silica sol, antimony pentoxide sol,
It can be stably mixed with a dispersion such as an anionic or nonionic surfactant, an aqueous solution of polyvinyl alcohol or the like, an anionic or nonionic resin emulsion, water glass, an aqueous solution of aluminum phosphate or the like.

The dry coating film of this sol is transparent and has a high refractive index of about 1.8 to 1.9, and has high bond strength and hardness, and also has high water resistance and adhesion. Furthermore, antistatic property,
It also has good heat resistance and wear resistance. Therefore, this sol has many uses. For example, a flame retardant or non-flammability imparting agent, a film refractive index improver, a hard coating agent,
Antistatic agent, anti-slip agent, dyeability improver, wettability improver, anticorrosion improver, various paints, adhesives, molding binders,
It can be used as an agent for preventing dusting of inorganic fibers, a surface treatment agent for glass, ceramics, plastics, metal, etc., a catalyst and the like.

Such a sol of the present invention can be simply prepared by the method of the present invention from an aqueous solution of tungstate and an aqueous solution of stannate.
And it can be efficiently manufactured as an industrial product.

Claims (4)

[Claims] 1. Tungsten oxide (WO ₃ ) and tin oxide (SnO)
A stable tungsten oxide-tin oxide composite sol containing the composite colloidal particles of ₂ ) and an alkali metal, ammonium or amine cation. 2. The stable tungsten oxide-tin oxide composite sol according to claim 1 contains WO ₃ and SnO.
The weight ratio of ₂ is 2 to 100 as WO ₃ / SnO _2, and the amount of the cation of the alkali metal, ammonium or amine the total amount of WO ₃ and SnO ₂ contained in the sol
M ₂ O / WO ₃ + SnO ₂ (wherein M represents an alkali metal atom, an ammonium group or an amine molecule) as a molar ratio of 0.02
Stable tungsten oxide-tin oxide composite sol, characterized in that it is ~ 0.7. 3. An aqueous solution of tungstic acid obtained by treating an aqueous solution of tungstate with a hydrogen cation exchanger and an aqueous solution of stannate as a WO ₃ / SnO ₂ weight ratio of 2 to 100. A method for producing a tungsten oxide-tin oxide composite sol, which comprises mixing with 4. A mixed solution obtained by the mixing according to claim 3 is mixed with M ₂ O (where M is an alkali metal atom or ammonium) based on the total number of moles of WO ₃ and SnO _{2 in} the mixed solution. Group or amine molecule) molar ratio M ₂ O / WO ₃ +
A method for producing a tungsten oxide-tin oxide composite sol, which comprises adjusting a molar ratio such that SnO ₂ is 0.02 to 0.7.