JPH03218928A - Zirconia organosol and production thereof - Google Patents

Abstract

PURPOSE:To obtain a coating agent for rendering functions such as heat resistance, heat reflecting property, heat insulating property, UV absorbency and hardness to a substrate or improving such functions of a substrate by adding an org. solvent to a zirconia hydrosol and substituting the solvent for the water in the hydrosol by distillation under heating. CONSTITUTION:An org. solvent is added to a zirconia hydrosol produced from an aq. zirconium salt soln. and urea or a zirconia hydrosol obtd. by hydrolyzing a reaction product of zirconyl ammonium carbonate with a chelating agent and the solvent is substd. for the water in the hydrosol by distillation under heating to obtain a desired zirconia organosol. A beta-dicarbonyl compd. such as beta-diketone, beta-ketonic acid or ester thereof is suitable for use as the chelating agent. The zirconia organosol forms a transparent crystalline zirconia coating film having high hardness especially by heat treatment at low temp.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a zirconia sol and a method for producing the same.
Specifically, the present invention relates to a zirconia sol whose solvent is an organic solvent and a method for producing the same.

The zirconia sol of the present invention is used as a coating agent, an inorganic binder, or a composite material of zirconia and an organic or inorganic compound. In particular, the zirconia sol of the present invention can be used for metals and glasses. Coating the surface of a base material such as plastic to make the base material heat resistant and wear resistant. chemical resistance,
Insulating, anti-reflective, heat reflective. Heat shielding properties, UV absorption.
It can be suitably used as a coating agent to impart or improve functions such as hardness. Above all, the transparent and crystalline coating film obtained from the zirconia sol of the present invention, alone or laminated with other materials, has the advantage that the above-mentioned functions can be imparted to a transparent substrate such as glass without impairing its transparency. be.

(Prior Art) Various methods are used to form a zirconia film, including physicochemical methods such as vacuum evaporation and spasotering, and coating with a zirconium-containing composition liquid. Among these conventional methods, the coating method is relatively easy to scale up and industrialize, so research has been progressing in various places in recent years.

Conventionally, organic solvent-based zirconium-containing composition liquids have had zirconium alkoxide as a substrate as a component thereof. However, zirconium alkoxide has a very fast hydrolysis rate, and as a result, the coating solution is unstable, and it is difficult to prepare a uniform coating composition because it is susceptible to hydrolysis due to moisture and carbon dioxide gas in the air, which may affect its storage stability. Ta. Furthermore, for the same reason, the coating conditions are narrow, the workability is poor, and it is difficult to form a film without holes. For this reason, zirconium alkoxide hydrolysis inhibitors such as glycols are added to the coating composition solution, or zirconium alkoxide and β-dykenent are added. Zirconium compounds obtained from β-ketonic acid and β-dicarbonyl compounds such as its esters are used as coating liquid compositions. However, the coatings obtained by these methods also have the disadvantage that they are prone to cracking and uneven thickness, making it difficult to obtain a homogeneous coating.

(Problems to be Solved by the Invention) The present invention provides a zirconia sol dispersed in an organic solvent in order to solve the above-mentioned problems of the conventional method. Suitable for forming zirconia coating films with high hardness and hardness. It also provides an organic solvent-dispersed zirconia sol to which a compound of a metal element other than zirconium is added, and unless otherwise specified, the zirconia sol is also collectively referred to as zirconia sol in the present invention.

(Means) In order to form a zirconia coating film in the present invention, there are a step of preparing a coating solution, a step of forming a coating film, a step of drying and gelling the coating film, and a heat treatment of the gelled film to convert it into a zirconia film. Including process. In coating using a solution method as in the present invention, the preparation of the coating solution is a fundamentally important issue.In the present invention, a zirconia sol is once generated in an aqueous solvent, and then the zirconia sol is coated with the aqueous solvent replaced with an organic solvent. This is the main component of the solution. Zirconia has monoclinic and tetragonal systems. It has a cubic crystal system, and a monoclinic system, which is a stable phase, usually occurs at temperatures above about 600°C. However, the crystallization temperature of zirconia and its crystal system are affected by the type of starting materials, reaction method, gel heat treatment method, etc. The present invention is an organic solvent-dispersed zirconia sol in which a zirconia sol that can be crystallized and highly densified at low temperatures is first synthesized in an aqueous solvent, and then water is replaced with an organic solvent in order to have the properties necessary as a coating solution. This was made based on the knowledge that the coating film targeted by the invention can be obtained, and will be described in more detail below.

The method for producing zirconia sol from an aqueous zirconium salt solution is to peptize the precipitate produced by the reaction between the aqueous zirconium salt solution and a basic substance with an acid, or to add the basic substance to an aqueous zirconium salt solution to an extent that no precipitation occurs. A method is known in which a sol is produced by injection mixing up to a pH of .

Furthermore, a method is known in which a zirconia-based colloidal sol is obtained by heating and hydrolyzing an aqueous solution containing a zirconium salt under normal pressure or increased pressure.

Then, the ions in the sol solution are removed from the sol produced by these methods.

In order for the zirconia coating film to crystallize at low temperatures, the shape, particle size, and uniformity of the sol particles are extremely important. Therefore, it is important to prepare a universal zirconia sol, and the present inventors As a result of intensive study on the preparation method of zirconia sol, it was found that acidic type and neutral type zirconia sols prepared by the following method satisfy the gist of the present invention.

CI) Acidic zirconia sol and its preparation method This sol is a transparent zirconia sol produced from an aqueous zirconium salt solution and urea, and its preparation method will be described in detail.

First, zirconium oxychloride. A zirconia sol is produced by adding urea to an aqueous solution of a zirconium salt selected from water-soluble zirconium salts such as zirconium nitrate, zirconium sulfate, or zirconium acetate, and heating the solution.

This reaction is characterized by the fact that the concentration of ammonia produced by hydrolysis of urea according to the following formula is extremely uniform in the aqueous solution, and the particle size of the zirconia sol produced from this ammonia and zirconium salt is extremely small and uniform. There is.

(N!{z) zco + fho→2NHi+COz
The reaction is stopped while the sol thus obtained remains transparent.

The p value of the sol after the reaction is 1.2 to 2.9.

After cooling the sol, it is washed and concentrated using an ultrafiltration membrane. The ions in the sol are discharged from the system along with water. If the concentration of ions in the sol after concentration is high, the process of adding pure water to the sol, washing and concentrating is repeated to reach the desired ion concentration. In addition, as a method for removing ions, is it necessary to maintain a certain level of ion concentration? It is also an effective method to wash with ultrafiltration and then use an ion exchange resin to remove ions. Concentration using an ultrafiltration membrane is limited by the ultrafiltration membrane, but it is possible to concentrate up to 20% by weight as zrOz. If the concentration is higher than this, the sol is concentrated by heating. This concentration needs to be carried out at a temperature of the sol of 80°C or lower, preferably 60°C or lower, more preferably 40°C or lower, and can be carried out efficiently under stirring and reduced pressure. The transparent zirconia sol thus obtained can have a concentration of up to 50% by weight as ZrO and is stable for a long period of time.

In addition, when using zirconia sol as a thick film coating or as an inorganic binder with higher strength, it is advantageous to use it at a high concentration as Zr02, or when using it as a coating agent or an inorganic binder in a high lA region,
Calcium is used as a stabilizer to prevent volume changes caused by phase transformation of zirconia. Compounds consisting of elements such as magnesium and yttrium must be added to the sol, and the mechanical properties such as hardness and adhesive strength of the coating film, as well as electrical resistance, need to be added to the sol. antistatic. tIf you want to improve electromagnetic properties such as magnetic wave prevention, optical properties such as light absorption ability, and refractive index compared to those of zirconia alone, compounds of metal elements other than zirconium are added to zirconia sol. There is a need. When the zirconia sol produced by the above method has such a high concentration or coexists with other metal element compounds, the zirconia sol may become highly viscous or become unstable over time, resulting in thickening and gelation. In such cases, viscosity adjustment and stability over time can be improved to some extent by adjusting the pH of the sol, but the effects are insufficient. As a result of further investigation into this problem, we found that the above-mentioned transparency, the viscosity of the sol, and the viscosity of the zirconia sol can be improved by adding a chelating agent to the zirconia sol, resulting in a higher concentration. It was found that adjustment and long-term stabilization of the sol over time is possible.

That is, as mentioned above, a zirconium-based sol in which a chelating agent and/or a compound of a metal element other than zirconium is blended with transparent zirconium obtained from an aqueous zirconium salt solution and urea can greatly expand the uses of zirconia sol. , its preparation method is described below.

Chelating agents that can be used in the present invention include oxyphenols such as catechol and pyrogallol, and amino alcohols such as diethanolamine and triethanolamine. Glycolic acid. Oxyacids such as lactic acid and hydroxyacrylic acid, and their ester acids such as methyl, ethyl, and hydroxyethyl. Acetylacetone. β-diketones such as penzoylacetone, stearoylbenzoylmethane, dibenzoylmethane, acetoacetic acid.
β-carboxylic acids such as propionyl acetic acid and benzoyl acetic acid, and their methyl, ethyl, n-propyl, and i-propyl acids. n-butyl. Examples include esters such as t-butyl.

Among these, β-dicarbonyl compounds such as β-diketones, β-keto acids and esters thereof are preferably used.

The amount of the chelating agent to be added may be relatively small, and a sufficient effect is exhibited within the range of 0.02 to 1 mole of zirconia in the sol. Note that even if it is added in an amount exceeding 1 mole, the quantitative effect is small and it is not economical.

The metal element compound used in the present invention includes vanadium, which has a higher valence than zirconium. diopter, tantalum, chromium, molybdenum, tungsten, etc., or titanium, tin, silicon, etc. with the same valence as zirconium,
Cerium, etc., as well as aluminum and yttrium, which have a lower valence than zirconium. Examples include compounds such as indium, calcium, and magnesium. By using these metal elements alone or in combination with zirconia, mechanical properties are improved compared to when zirconia is used alone. It is possible to add and improve electromagnetic, optical, and other functions.

There are no particular restrictions on the timing and method of adding the chelating agent and metal element compound, and they can be added at any time from before the formation of the transparent zirconia sol to after the formation. For example, (1) heating an aqueous zirconium salt solution and urea to form transparent zirconia, (2) concentrating the transparent zirconia sol using an ultrafiltration membrane, (3) concentrating it by ultrafiltration, Furthermore, it may be added after being concentrated by heating.

Furthermore, (4) it may be added to a mixed solution of a zirconium salt aqueous solution and urea. In this case, since each component can be mixed uniformly before the sol generation reaction, a more homogeneous zirconia-based sol can be obtained, and furthermore, it is possible to obtain a zirconia-based sol with a higher degree of homogeneity. It is possible to produce a sol.

The zirconia-based sol thus obtained is stable at room temperature for more than 6 months even at high concentrations.

[■] Neutral zirconia sol and its preparation method Zirconia sol produced from a zirconium salt aqueous solution by a conventionally known method is stable only in the acidic pH range, and its viscosity increases in the neutral or alkaline range. or gel. Therefore, it cannot be used as a sol in the presence of an alkaline substance, and when a sol is produced in an aqueous solvent as the purpose of the present invention and then the water is replaced with an organic solvent, the water content is When this decreases, viscosity and gelation may occur, making it impossible to reduce the water content significantly, or narrowly limiting the types of organic solvents that can be substituted. Furthermore, when applied as a coating agent to metallic materials, the problem of corrosion due to acid content remaining in the sol occurs.

Neutral zirconia sol was invented to address the above problems, and is a zirconia sol that is stable over a wide pH range, particularly in the neutral to alkaline range.

The sol is prepared by mixing an aqueous solution of zirconyl ammonium carbonate and a chelating agent to once convert the zirconyl ammonium carbonate into a zirconium chelate compound, then heating and hydrolyzing the chelate compound, and then filtration using an ultrafiltration membrane if necessary. Obtained by washing.

The neutral type sol will be explained in detail below.

Zirconyl ammonium carbonate is usually obtained by reacting zirconyl carbonate with an alkali carbonate such as ammonium carbonate or ammonium hydrogen carbonate.

? ZrOC(h ・8H20+4NH4HCOy+(N
H4)zcOi →2(NHa) iZrOH(CO
a) s ・2HzO + 5HzO This zirconyl ammonium carbonate is dissolved in pure water to make a zirconyl ammonium carbonate aqueous solution, but in the above reaction, an excessive amount of alkali carbonate is used, the structure of zirconyl ammonium carbonate is complicated, or carbonate Although it is difficult to unambiguously define a zirconylammonium carbonate aqueous solution because there are many unknowns about the behavior of zirconylammonium in an aqueous solution, in the present invention, a zirconylammonium carbonate aqueous solution, which is commonly referred to as a zirconylammonium carbonate aqueous solution, is used. and
A commercially available aqueous solution of zirconyl ammonium carbonate is preferably used, and its properties include a PTT of 8 to 9 and a concentration of 12 to 14% by weight as ZrO.

When an aqueous solution of zirconyl ammonium carbonate is heated above 60°C, the zirconyl ammonium carbonate is hydrolyzed into hydrous zirconia with the generation of gases such as ammonia and carbon dioxide. This reaction solution has an alkaline pH and exhibits properties as a sol. It becomes like this. However, if the reaction is continued for W1, the viscosity of the reaction solution increases and gelation occurs in a relatively short period of time, and only a small amount of zirconyl ammonium carbonate can be hydrolyzed. The present inventors investigated a method for stably continuing the hydrolysis reaction of zirconyl ammonium carbonate and found that the desired neutral zirconia sol could be obtained by the following method. That is, an aqueous solution of zirconyl ammonium carbonate and a chelating agent are mixed to form a reaction product between the zirconyl ammonium carbonate and the chelating agent, and then the aqueous solution containing the product is heated to 60°C or higher to undergo hydrolysis. This method involves conducting a reaction to obtain zirconia sol. Specifically, when an aqueous solution of zirconyl ammonium carbonate is placed in a stirred tank reactor and a chelating agent is added while stirring, the zirconyl ammonium carbonate and chelating agent react rapidly at room temperature. After the reaction, when the reaction solution is heated to 60° C. or higher, the hydrolysis reaction of the reactant between zirconyl ammonium carbonate and the chelating agent proceeds while generating gas mainly consisting of carbon dioxide and ammonia. During the reaction, the reaction solution does not increase in viscosity, and the reaction can be completed while maintaining the transparency of the reaction solution. The pH of the reaction solution after the reaction is from weakly alkaline to neutral and weakly acidic, and even if an alkaline substance is added to this reaction solution, the reaction solution does not thicken or gel, and the reaction solution remains in the neutral range. Alternatively, it is used as a stable zirconia sol even in an alkaline region.

One of the characteristics of this sol preparation method is that during the above hydrolysis reaction, ammonium ions and carbonate ions, which are impurity ions, are discharged from the system as ammonia and carbon dioxide. The reaction solution of the hydrolysis reaction of the reaction product of the chelating agent and the chelating agent can be used as a zirconia sol without special washing, and it can also be concentrated to a high concentration by ordinary heating and evaporation. However, if a trace amount of unreacted substances, carbonate ions, ammonium ions, etc. remaining in the reaction solution are to be removed to obtain a zirconia sol of higher purity, an ultrafiltration membrane is used to remove acidic zirconia sol. It can be easily washed using the same preparation method as described above.

The chelating agent used in this preparation method is catechol. Oxyphenols such as birogallol; diethanolamine. Amino alcohols such as triethanolamine; glycolic acid. Citric acid, tartaric acid. Lactic acid. Mandelic acid. Oxyacids such as malic acid and hydroxyacrylic acid, and their methyl and ethyl acids. Esters such as hydroxyethyl, oxyaldehydes such as glycolaldehyde; oxalic acid. Polycarboxylic acids such as malonic acid; amino acids such as glycine and alanine; acetylacetone and penzoylacetone. stearoyl acetone,
Stearoyl acetone. Stearoyl bezoylmethane. β-diketones such as dibenzoylmethane. as well as acetoacetic acid and probionyl acetic acid. β-ketonic acids such as benzoylacetic acid and their methyl, ethyl, n-propyl, isopropyl, n-butyl. One type or a combination of two or more types of esters such as t-butyl can be used. Among these, glycolic acid and citric acid.
Tartaric acid. Lactic acid. Mandelic acid. Malic acid. Oxyacids such as hydroxyacrylic acid and β-diketones such as acetylacetone are preferably used. More preferably, α, β, and γ-oxyacids are α, β, and γ-oxyacids, respectively.
α-, β- with a functional group having an oxygen atom on the carbon of γ
, T-catonic acids or their esters.

The amount of chelating agent used varies depending on the type of chelating agent used, but the ratio of chelating agent (number of moles)/zirconia (number of moles) is 0.02/1 to 4/1, preferably 0.02/1 to 4/1.
1 to 3/1, more preferably 0. 5/1~2/
It is best to select a value within the range of 1.

If the amount of chelating agent used is too small, certain organic zirconium salts formed by the reaction between the chelating agent and zirconyl ammonium carbonate will be degraded when hydrolyzed by the method of the present invention compared to when zirconyl ammonium carbonate alone is used. It exhibits similar behavior, and the hydrolysis reaction cannot be continued and the chelating agent has no effect.On the other hand, even if it is used at a ratio exceeding 4/1, no special effect can be obtained and it is not economical.

The hydrolysis reaction in this method may be carried out at 60° C. or higher, and the reaction is preferably carried out in a pressurized atmosphere to promote the reaction.

Practical reaction temperatures are 60-300°C.

In this method, the reaction solution after the completion of the hydrolysis reaction has a transparent appearance and its 9H is approximately 7, and can be used as a zirconia sol, but this sol uses a chelating agent in the preparation process. Because of this, the sol has extremely high stability.Even when the concentration is high, the sol has a low viscosity and is stable over time. Preparation of the system sol is also extremely easy. As with the method for preparing acidic zirconia sol described above, there are no particular restrictions on the timing or method of adding metal compounds other than zirconium. A type zirconia sol is obtained.

The above-mentioned acidic and neutral zirconia sols, which are aqueous solvents, are used as coating agents, inorganic binders, and the like. When these are used, for example, as a coating agent, the coated gel film undergoes crystallization upon heat treatment at about 360° C. or higher. The heat treatment temperature at which the zirconia gel crystallizes, the type of crystals, the crystallite size, etc. are influenced by the preparation method of the zirconia sol, the starting material, the shape and particle size of the sol particles, and the conditions such as the heat treatment atmosphere. Different types of zirconia sol are used depending on the purpose, or both are used in parallel, such as alternately.

When the zirconia sol is used as a coating agent, the water in the sol is usually replaced with an organic solvent for reasons such as adjusting the drying rate of the coating film and adhesion to the substrate. In this replacement method, an organic solvent is added to the aqueous zirconia sol obtained by the method described above, and this mixed solution is heated and distilled to discharge water or a mixture of water and organic solvent from the system. A method of replacing the zirconia sol in the aqueous solvent with that in the organic solvent, or using an ultrafiltration membrane, draining the water and organic solvent out of the system, and adding the organic solvent to the original mixed solution while converting the water into the organic solvent. A flow-through replacement method is used industrially. These methods can efficiently replace the water content until the water content in the zirconia sol that has been replaced with an organic solvent is approximately 1% by weight or less, which is sufficient for use as a coating agent. The water content can be reduced to a level that can be handled.

If you want to reduce water content further, use molecular sheep or calcium carbonate. It is also effective to use a moisture adsorbent such as aluminum phosphate.

Examples of organic solvents used in the present invention include acetone, methylethyl. Ketones such as ketones; carbone M such as formic acid and acetic acid; esters such as ethyl acetate and methyl formate; methanol. ethanol. Alcohols such as isopropanol; polyvalent alcohols such as ethylene glycol and glycerin? Calls and their esters such as methyl cellosolve and ethyl cellosolve; and other solvents such as one or a mixture of two or more hydrophilic organic solvents having hydrophilic groups such as one COOH or -OH group in the molecule such as glycolic acid and malic acid. By replacing these with water,
No phenomena such as gelation or clouding of the sol are observed, and a transparent organic solvent-dispersed zirconia sol can be obtained from both acidic and neutral zirconia sol in an aqueous solvent.

The organic solvent-dispersed zirconia sol thus obtained is ZrO
(2) It was possible to contain up to 25% by weight, and it was stable even when stored for more than 6 months, with no tendency to increase viscosity. When using the organic solvent-dispersed zirconia sol of the present invention as a coatin agent, alcohols such as ethyl alcohol and isopropanol may be added to adjust the viscosity, or zirconia, titania, alumina, etc. may be added. Silicon carbide. It can be mixed with powder such as zircon to form a slurry-like coating liquid to further improve the hardness and other physical properties of the coating film, or it can be applied to thick film coatings, and pigments such as iron oxide and cobalt can be added. color coating films can be produced.

Note that it is of course possible to prepare a zirconia-based sol dispersed in an organic solvent by replacing water with an organic solvent in the zirconia-based sol to which a compound of a metal element other than zirconium is added in the same manner as described above. However, when preparing the coating solution, a compound of a metal element other than zirconium may be added to the organic solvent-dispersed zirconia sol to be used as an organic solvent-dispersed zirconia-based sol. At this time, as explained above, a chelating agent is also added if necessary.

A coating liquid prepared based on zirconia and a zirconia-based sol dispersed in an organic solvent is used and then coated on a substrate. Coating methods include spray, brush, and dab. spin. It is carried out by a roll method, etc., and the coating layer thickness per coating ranges from submicrons in the spin method to several hundred microns in the brush and roll methods.

It is also possible to apply multiple coatings, and the coatings are applied after the coating layer has dried or after heat treatment.

Conventional methods can also be applied to underground treatment of the base material to ensure adhesion to the base material, such as simply cleaning the coated surface with pure water or alcohol, and cleaning metal surfaces with alkaline. It is desirable to perform a complete degreasing.

In addition, when increasing the thickness of the coating layer, a coating film with strong adhesion strength can be obtained by blasting the coating surface. The coating liquid according to the present invention is not easily affected by the environmental atmosphere such as moisture in the atmosphere.
In the coating process, a homogeneous coating film can be obtained without requiring special consideration.

The coating thus formed is then dried and gelled. If the coating film is thin, it will dry and gel quickly at room temperature and in the atmosphere, but if the coating film is thick, it will quickly gel.
Drying is carried out at 5 to 80° C. for 1 to 24 hours, but at this time, it is necessary to adjust the drying rate to prevent cracks in the film, and a wet drying method is also employed.

Although the gelled coating film of the present invention is of poor quality, its properties such as film hardness and adhesion are suitable for practical use. However, there is also a desire to further improve the various properties of the coating film when coating materials such as plastics that are not suitable for high temperature drying. In such cases, an organic solvent-dispersed zirconia sol prepared from the acidic zirconia sol of the present invention is used, and the resulting coating film is dried in an ammonia gas atmosphere, or the coating film is dried in an alkaline atmosphere. An effective method is to contact the material with the material and then dry it, or to coat the material alternately with an organic solvent-dispersed zirconia sol prepared from a neutral zirconia sol.

The coated gel membrane is then heat treated. For heat treatment, the temperature and time are determined by considering the heat resistance of the base material. When physical characteristics such as hardness of the coating film are required, it is desirable that the heat treatment temperature is 400° C. or higher.

Note that the gelled film crystallizes to become an oxide film at temperatures above 360°C, and considerable strength can be imparted by heat treatment at 110°C, preferably 150°C or above. These produced films are transparent and have high visible light transmittance, and are used for optical applications that take advantage of zirconia's high refractive index. (Effect of the invention) By properly using the water-dispersed acidic type and neutral type zirconia sol of the present invention, the zirconia sol can be used without being restricted by pH, and both types of sols can be prepared. In both cases, reactions under heating are used. Therefore, by adjusting the thermal and chemical conditions, the shape, size, crystallinity, etc. of sol particles can be quantified relatively easily. The properties of this water-dispersed zirconia sol are inherited by an organic solvent-dispersed zirconia sol obtained by replacing water with an organic solvent.

Is the zirconia sol prepared from the zirconia sol obtained by the present invention crystallized by heat treatment at low temperature? By coating with the coating solution using the organic solvent-dispersed zirconia sol of the present invention, a crystalline coating film can be obtained by low-temperature heat treatment, and by coating on a transparent substrate such as glass, a transparent coating film can be obtained. A coating film with high strength and high refractive index can be formed.

[Example 1] Z. ．． 18% by weight aqueous zirconyl nitrate solution as 0■
0 kg and 3 kg of urea were added to 200 liters of pure water. Next, this aqueous solution was heated and boiled for 6 hours to obtain a transparent zirconia sol. After cooling this sol, it is introduced into an ultrafiltration device and filtered at Z, 0. The sol was then concentrated to 10% by weight, then pure water was added to the concentrated sol to obtain the zirconia concentration before concentration, and washing was performed a total of 5 times, in which the sol was concentrated again using an ultrafiltration membrane. After washing, 10% by weight sol was heated at 50℃ under vacuum.
A transparent zirconia sol having a concentration of 20% by weight was obtained by heating and condensing while maintaining the following concentration. The pH of this zirconia sol is 1
．． 5. The viscosity was 40 cp and it was stable for a long period of time.

? Example 2 A commercially available zirconyl ammonium carbonate aqueous solution containing 13% by weight of 2102 was placed in a 10 f flask. To this, 1040 g of glycolic acid was gradually added while stirring. Next, the flask was heated with a mantle heater to carry out a hydrolysis reaction. Reaction liquid temperature is 50-60
Ammonia-smelling gas began to be generated at ℃, and as the temperature rose, it bubbled violently, and the reaction progressed while exhausting gases generated from unnecessary ions in the sol, such as ammonia and carbon dioxide, out of the system.

Foaming subsides by reacting at a reaction temperature of about 100°C for about 3 hours, and in this state, an aqueous yttrium acetate solution is added to the reaction solution. As No. 03, it was gradually added to Z,0■ in an amount of 3 mol %. After the addition, heating was continued for another 12 hours while adding pure water to the flask as needed, and Z, 0
YzOs is 30% by weight and 3% by mole relative to Z,OR.
An added zirconia-based sol was obtained. The sol had a transparent appearance, a pH of 7, a viscosity of 35 cp, and was stable for a long period of time.

? Example 3 345 g of ethylene glycol monoethyl ether was dissolved in 300 g of the zirconia sol prepared in Example 1 to form a uniform solution. The solution was heated and distilled, gas consisting mainly of water vapor was discharged from the system, and water in the sol was replaced with ethylene glycol monoethyl ether. When the temperature of the solution reached 124.3°C, heating was stopped and the ZrO. A zirconia sol containing 18% by weight was obtained. The sol has a transparent appearance, a water content of 3.5% by weight, and a viscosity of 2.
It was stable for more than 6 months at 0 cp.

[Example 4] 370 g of ethylene glycol was dissolved in 300 g of the zirconia sol prepared in Example 2 to form a uniform solution. In the same manner as in Example 3, water in the sol was replaced with ethylene glycol. When the temperature of the solution reached 197°C, heating was stopped, and the isothorium dispersed in ethylene glycol was added as Y20, containing 3 mol% of z.
．． 25 as 0■? % sol was obtained.

The sol has a transparent appearance and a water content of 1% by weight.
It had a viscosity of 65 cp and was stable for more than 6 months.

[Example 5] Isopropyl alcohol was added to 500 g of the zirconia sol prepared in Example 1, and this solution was placed in a liquid receiving tank of an ultrafilter. Continuously perform the ultrafiltration operation while adding isopropyl alcohol to the liquid receiving tank, and replace the water in the sol with isopropyl alcohol while discharging the mixed solution of water and isopropyl alcohol to the outside of the system. By performing the operation Z. ．． A zirconia sol dispersed in isopropyl alcohol containing 15% by weight was obtained. The sol has a transparent appearance, a water content of 2% by weight, and a viscosity of 4.
It was stable for more than 6 months at 0 cp.

[Example 6] Isopropyl alcohol was added to 100 g of the zirconia sol dispersed in ethylene glycol monoethyl ether prepared in Example 3 to prepare a coating solution containing 12% by weight of ZrO.

A quartz glass degreased with acetone was immersed in this coating solution, pulled up and coated at a constant speed of 3.5 am/win, and then dried at room temperature in the atmosphere to form a gelled film on the quartz glass surface. After drying, the quartz glass was heat-treated at 400° C. for 30 minutes in an air atmosphere to form a colorless and transparent coating film with a thickness of 0.14 μm on the quartz glass surface, exhibiting an interference color. In order to examine the crystallinity of this coating film, a portion of the coating liquid was poured into a glass wide plate bottom container, and the coating liquid was dried while controlling the drying rate to a thickness of 0.
A transparent plate-shaped gel sample of 1 crane was prepared, and a transparent thin plate of zirconia was obtained by heat-treating this sample under the same conditions as for the coating film described above. Electron microscopic observation of this thin plate revealed that this thin plate was composed of microcrystallite, and X-ray diffraction of this thin plate showed that most of the microcrystals were tetragonal.

[Example 7] Ethylene glycol monomer prepared in Example 3 -0, ZrO in zirconia sol dispersed in ether
Tungsten ethoxide and ethanol were added to give a concentration of 15 mol % based on ZrO. 10% by weight
A coating solution with a certain concentration was prepared. This coating solution was coated on quartz glass that had been degreased with acetone using a spin coating method. After drying, a transparent tetragonal zirconia film doped with 103 was obtained by heat treatment at 400°C. This composite film is used to improve the electrical properties such as electrical resistance or optical properties of the zirconia film.

[Example 8] To 300 g of the isotria-containing zirconia sol dispersed in ethylene glycol prepared in Example 4, 75 g of isopropyl alcohol and 25 g of an acrylic organic binder were added and thoroughly stirred. 240 g of isotria-partially stabilized zirconia powder having a particle size of 325 mesochander was added to this solution, and mixed in a ball mill for 16 hours. The thus obtained slurry was repeatedly coated on a porous zirconia plate with a brush, dried and then fired at 1200°C.

A dense, smooth layer with a thickness of one inch was coated on the porous plate surface.

Claims (1)

[Claims] 1. An organic solvent-dispersed zirconia sol obtained by adding an organic solvent to a water-dispersed zirconia sol and replacing water with the organic solvent. 2. The organic solvent-dispersed zirconia sol according to claim 1, which uses a zirconia sol produced from an aqueous zirconium salt solution and urea. 3. The organic solvent-dispersed zirconia sol according to claim 1, which uses a zirconia sol obtained by hydrolyzing a reaction product of zirconyl ammonium carbonate and a chelating agent. 4. The chelating agent is oxyphenols, amino alcohols, oxyacids, polycarboxylic acids and their esters, oxyaldehydes, amino acids, β-dikentes, and α-, β-, γ-ketone acids and The organic solvent-dispersed zirconia sol according to claim 3, which is at least one selected from these esters. 5. The organic dispersed zirconia sol according to claim 1, wherein the organic solvent is a hydrophilic organic solvent. 6. An organic solvent is added to a zirconia sol produced from an aqueous zirconium salt solution and urea, or a zirconia sol obtained by hydrolyzing a reaction product of zirconyl ammonium carbonate and a chelating agent, and then heated and distilled to remove water from the organic solvent. A method for producing an organic solvent-dispersed zirconia sol, characterized by substituting with. 7. Add an organic solvent to the zirconia sol produced from a zirconium salt aqueous solution and urea, or the zirconia sol obtained by hydrolyzing the reaction product of zirconyl ammonium carbonate and a chelating agent, and use an ultrafiltration membrane to remove water. 1. A method for producing an organic solvent-dispersed zirconia sol, which comprises replacing zirconia sol with an organic solvent.