JPH09221324A - Titanium dioxide ceramic coating material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: A stable ceramic coating material contg. titanium dioxide excellent in transparency, adhesion and photocatalytic performance as a principal component and to provide its production. SOLUTION: An aq. soln. of a titanium compd. is allowed to react with a peroxide, preferably hydrogen peroxide and the resultant liq reactional product is subjected to impurity ion removal treatment to obtain the objective ceramic coating material contg. titanium dioxide or colloidal titanic acid and peroxotitanic acid so that the weight ratio of H2 TiO3 to H4 TiO5 is regulated to 20,000:(1-500) and not practically contg. impurity ions.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a titanium oxide-based ceramic coating material and a method for producing the same. More specifically, the present invention relates to a ceramic coating containing titanium oxide as a main component, which is easy to impart a photocatalytic function, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as a ceramic coating which is superior in heat resistance and abrasion resistance to organic coatings, alkali metal silicates, phosphates, silica sols, metal oxides, etc. Paints are known. These paints have the characteristics of inorganic paints in terms of excellent heat resistance, abrasion resistance, etc. as described above, but in recent years, in addition to the above-mentioned characteristics of the film obtained by the ceramic paint, a new function has been added. Attempts have been made to focus on metal oxide systems.

Among the metal oxides, titanium oxide has a high photocatalytic effect on the coating film, so that a titanium oxide film having such a photocatalytic effect is formed on the surface of an object to be coated such as metal, glass or ceramics. Therefore, it is known that it is effective for prevention of adhesion of dirt, purification of air and water quality, rust prevention, antibacterial, prevention of algae growth, purification of air and water quality, and the like. For such applications, various titanium oxide paints for forming a better titanium oxide film on the surface of the material and some methods for producing the same have been proposed so far.

The most common method of forming a titanium oxide film is a method of applying a paint containing a hydrolysis product of titanium alkoxide, that is, a sol-gel method.
As a technique similar to this, for example, Japanese Patent Laid-Open No. 4-835
37, that is, a method for preparing a coating by adding amide and glycol to titanium alkoxide, and a method described in JP-A-7-100378, that is, adding alcohol amines to titanium alkoxide. A method of preparing a paint is disclosed.

In addition to this, Japanese Patent Laid-Open No. 6-29351
No. 9 discloses a method in which fine particles of titanium oxide crystallized by hydrothermal treatment are dispersed using a dispersant and the dispersion is applied. As yet another method, crystalline titanium oxide particles are disclosed. There is known a method in which a binder such as water glass, colloidal silica, or a fluororesin is mixed and applied.

However, in the method using the sol-gel method,
There are problems that the acid used for hydrolysis remains in the paint, amines and glycols added as additives easily remain in the film, and the raw material is expensive. In addition, the method of applying crystal-grown titanium oxide has a problem that the adhesion of the film is poor and the formed film does not become transparent. Further, when a binder is used for this, the coating property and adhesion of the paint are improved, but the titanium oxide content of the film is reduced, so that the photocatalytic ability is not sufficiently exhibited.

[0007]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the above-mentioned problems of the prior art, and contains almost no impurities harmful to the photocatalytic activity of titanium oxide, and transparent oxidation is possible only by drying at room temperature. (EN) It is intended to provide a peroxotitanic acid-containing ceramic coating material having excellent coatability and adhesiveness capable of forming a continuous titanium film, and a method for producing the same.

[0008]

Means for Solving the Problems As a result of intensive studies on the means for solving the above technical problems, the present inventors have found that titanic acid or titanium oxide colloid and peroxotitanic acid are contained in a specific ratio, It has been found that the above problems can be solved by a titanium oxide-based ceramic paint, the balance of which is substantially water, and the present invention has been completed.

The titanium oxide ceramic coating material of the present invention is
An aqueous liquid containing a colloid of titanic acid or titanium oxide and peroxotitanic acid, wherein the H ₂ TiO ₃ equivalent content of the titanic acid or titanium oxide colloid is the H ₄ TiO ₅ equivalent content of the peroxotitanic acid. To 20,000: 1 to 500, and is substantially free of other ions.

The production method of the present invention for producing the above-mentioned peroxotitanic acid-containing ceramic coating composition is a method in which a water-soluble titanium compound and a peroxide compound are reacted in water, and the resulting reaction product-containing aqueous liquid is contaminated. It is characterized by being subjected to an ion removing step. In the present invention,
Contaminant ions are ionic species that remain in the coating film after the ceramic coating material of the present invention is applied and baked.
^The components necessary for forming titanium oxide, such as ⁴⁺ , Ti ⁶⁺ , OH ⁻ , H ⁺ , and H ₂ O _2, are not included in the contaminant ions.

In the step of removing contaminant ions in the production method of the present invention, the reaction product-containing aqueous liquid may be subjected to a dialysis treatment using a semipermeable membrane or an electrodialysis treatment. Alternatively, in the step of removing contaminant ions of the method of the present invention, the reaction product-containing liquid may be subjected to electrolytic treatment in an electrolytic cell in which the cathode chamber and the anode chamber are partitioned by an ion exchange membrane. Good. Alternatively, in the step of removing contaminant ions of the method of the present invention, the reaction product-containing aqueous liquid may be contacted with an ion exchange material.

In the method of the present invention, the reaction product-containing aqueous liquid may be subjected to a heat treatment, and then to the step of removing contaminant ions. The heat treatment is 100
It is preferably applied at temperatures below ° C.

[0013]

DETAILED DESCRIPTION OF THE INVENTION In general, titanic acid is H ₂ TiO ₃ ,
Titanium oxide is represented by the chemical formula of TiO ₂ . Titanium oxide used in the present invention includes anatase type titanium oxide, rutile type titanium oxide, and amorphous titanium oxide,
Titanic acid also includes hydrous titanium oxide represented by TiO ₂ .nH ₂ O.

The above-mentioned aqueous colloid of titanic acid or titanium oxide is prepared from an acidic solution of a water-soluble titanium compound, preferably titanium trichloride, titanium tetrachloride, titanium sulfate, titanyl sulfate or titanium fluoride, preferably an alkaline solution. It can be prepared by neutralizing with, or by performing a heat pretreatment followed by a deionization treatment. In this case, if the particle size of the colloidal particles of titanic acid or titanium oxide exceeds 1 μm, the aqueous liquid and the coating film may lose transparency, so the particle size of the colloidal particles is 1
It is preferably not more than μm. Further, if the particle size of colloidal particles of titanic acid or titanium oxide is less than 10 ⁻⁵ μm, the obtained coating material may gel and lose fluidity, which is not preferable. The preferred colloidal particle size range is 1
It is from 10 ^-5 , more preferably from 10 ^-1 to 10 ^-4 μm.

Peroxotitanic acid, which is an essential component of the ceramic paint of the present invention, can be easily obtained by reacting a part of titanic acid or titanium ion with a peroxide compound, preferably hydrogen peroxide. Since hydrogen peroxide water becomes water after the oxidation reaction, it is advantageous because there are no unnecessary decomposition products and there is little risk of explosion etc., but other peroxides such as sodium peroxide and barium peroxide. May be used in the method of the present invention.

The weight ratio of the content of titanic acid or titanium oxide colloid to the content of peroxotitanic acid in the ceramic coating material of the present invention is [H ₂ TiO ₃ / H ₄ Ti].
It is 20,000: 1 to 500, that is, 40 to 20,000: 1 in terms of O ₅ ].

When the weight ratio of [H ₂ TiO ₃ / H ₄ TiO ₅ ] exceeds 20,000: 1, the colloidal sol in the obtained aqueous liquid tends to be unstable, and when it is less than 40: 1, it is obtained. A large amount of oxygen gas is generated during drying and baking of the coating film using the coating composition, which is not preferable because it causes defects in the coating film. More preferred [H ₂ TiO ₃ / H ₄ T
range of iO _5] weight ratio is 200～8,000: 1.

The total concentration of the titanium oxide or titanic acid colloid and the peroxotitanic acid in the coating composition of the present invention is not particularly limited, but is preferably 200 to 80,000 ppm.

The pH of the ceramic coating material of the present invention is preferably 2 to 10, and more preferably 3 to 9. If the pH value exceeds 10, the alkali content in the obtained coating film may be excessively high, and the photocatalytic effect may be insufficient. If the pH value is less than 2, the coating acidity is strong, and therefore its application. , The material to be coated may corrode during baking.

When a ceramic coating material is used in the titanium compound solution of the present invention, ceramics (eg, TiO ₂ , MoO ₃ , SiO) composed of various oxides, nitrides, carbides, etc. are added depending on the purpose of use. ₂ , TiN, B
N, WC, mica, etc.) and one or more kinds selected from metal fine particles such as zinc dust and aluminum dust.

Next, a method for producing the ceramic coating material of the present invention will be described. The peroxotitanic acid-containing ceramic coating material of the present invention can be prepared by the method of the present invention described below. That is, a water-soluble titanium compound and a peroxide compound are reacted in water, and the obtained reaction product-containing aqueous liquid is subjected to a contaminant ion removing step. The ions to be removed depend on the types of the water-soluble titanium compound and the peroxide compound, the presence / absence of the neutralization treatment, and the like. Also,
In the process of removing impurities, mainly reaction by-products,
The unreacted raw material anions are removed from the reaction product-containing aqueous liquid, and when alkali hydroxide or aqueous ammonia is added for neutralization, these alkaline cations are also removed.

The water-soluble titanium compound used in the method of the present invention is selected from titanium trichloride, titanium tetrachloride, titanium sulfate, titanium fluoride and the like, as described above. The peroxide compound used in the method of the present invention can be selected from hydrogen peroxide, sodium peroxide, barium peroxide, etc. as described above, but hydrogen peroxide is preferably used. The reaction between the titanium compound and the peroxide compound in the method of the present invention is carried out by adding the aqueous solution of the peroxide compound to an aqueous solution of the titanium compound at a concentration of 3 to 30% and at a temperature of 10 to 50 ° C. within a pH range of 0.5 to 3. It is preferably carried out. The amount of the aqueous peroxide compound solution used is preferably an amount sufficient to react with the total amount of the titanic acid compound to generate titanium oxide or titanic acid colloid and peroxotitanic acid in the above content weight ratio. For example, when hydrogen peroxide is used as the peroxide compound and a trivalent titanium compound such as titanium trichloride is used as the titanium compound, it is preferable to use about 3 mol of hydrogen peroxide to 1 mol of titanium (III). . When a tetravalent titanium compound is used as the titanium compound, titanium (IV) 1
It is preferred to use about 2 moles of hydrogen peroxide per mole.

In the method of the present invention, the step of removing contaminant ions is a step aiming at mainly removing anions such as reaction by-products such as Cl ⁻ , SO ₄ ²⁻ and F ^−. If it is neutralized with, for example, caustic soda or aqueous ammonia,
Impurity cations such as ⁺ or NH ₄ ⁺ can also be removed.

As a first method for removing impurities, a titanium compound solution is reacted with hydrogen peroxide solution, and then the reaction product-containing aqueous liquid is dialyzed or electrodialysed using a semipermeable membrane. Is to be applied. By this treatment, the contaminating anion and the contaminating cation in the reaction product-containing aqueous liquid are removed through the semipermeable membrane, and the titanium oxide or titanic acid colloid and the peroxotitanic acid-containing aqueous liquid are purified.

The second method for removing contaminant ions is to react a titanium compound solution with hydrogen peroxide solution, and then partition the resulting reaction product-containing aqueous liquid with an ion exchange membrane between the cathode chamber and the anode chamber. It is used as an electrolytic solution in an existing electrolytic cell and electrolyzes it. For the installation of the ion exchange membrane in the electrolytic cell, the cathode plate / anion exchange membrane / anode plate may be arranged in parallel with the bipolar plates, or the cathode plate / anion exchange membrane / cation exchange membrane / anode plate may be installed. The arrangement is preferable, and the latter arrangement is preferably used when a contaminating cation is contained. By this treatment, the contaminating anions in the reaction product-containing aqueous liquid are removed in the anion exchange membrane and the anolyte, and the contaminating cations are removed in the cation exchange membrane and the catholyte. In this way, a purified titanium oxide or titanic acid colloid and a peroxotitanic acid aqueous solution are obtained in the central electrolysis chamber.

A third method for removing impurities is to react a titanium compound solution with aqueous hydrogen peroxide, and then use the resulting reaction product-containing aqueous liquid with an ion exchanger such as an anion exchange resin (for example, Diaion). SA (trademark), Mitsubishi Chemical Co., Ltd.) cation exchange resin (for example, Diaion SK)
(Trademark, manufactured by Mitsubishi Chemical Corporation).
By this treatment, the contaminant ions in the reaction product-containing aqueous liquid are collected and removed by the ion exchanger to obtain a purified aqueous liquid containing titanic acid or titanium oxide colloid and peroxotitanic acid.

In the production method of the present invention, in order to prevent the hydrolysis of titanium ions in the aqueous solution of titanium compound, it is acceptable to add hydrochloric acid or sulfuric acid in excess to the reaction system.

In the method of the present invention, after the titanium compound is reacted with a peroxide compound such as hydrogen peroxide, the reaction product-containing aqueous liquid obtained is subjected to a temperature of less than 100 ° C. before the step of removing contaminant ions. It is preferable to heat it for a certain period of time. By this heat treatment, particles of titanic acid or titanium oxide colloid can be grown and controlled to an optimum size, which in turn can improve the stability of the paint and the photocatalytic property of the coating film. In the prior art, it is known that the titanium oxide colloidal liquid is heated at a temperature exceeding 100 ° C., but in this case, the colloidal particles produced are coarsened or the particle size distribution varies, and the quality becomes constant. There was a problem not to do. In the method of the present invention, it is more preferably 40 ° C or higher and lower than 100 ° C, further preferably 55 to 90 ° C, and the heating time is preferably 1 minute to 3 hours.
It is more preferably 0 to 60 minutes.

Generally, the higher the temperature of heat treatment and the longer the holding time, the larger the colloidal particle size. However, when the heat treatment temperature exceeds 100 ° C., the particle size of titanium oxide particles or titanic acid particles excessively grows to 1 μm. If so, the transparency and adhesion of the coating film may become insufficient as a result.

When the particle size of the titanium oxide colloid is controlled by heat treatment, titanium oxide particles which become the nuclei for growing colloid particles, such as hydrolysis products of titanium alkoxide and hydrolysis products of titanyl sulfate, or the like. A small amount of the dispersion liquid may be added before the heat treatment, which can improve the uniformity of the particle size. Also,
In the method of the present invention, before reacting the water-soluble titanium compound with hydrogen peroxide, or before the reaction by-product removal step, the aqueous solution is neutralized with caustic soda or aqueous ammonia to adjust the pH.
The value may be adjusted, and in this case, it is preferable to perform neutralization using an alkaline solution having a concentration of 1 N or less.

In the production method of the present invention, when the step of removing contaminant ions is carried out by a dialysis method or an electroosmosis method, the semipermeable membrane used is an RO membrane, cellophane membrane, bladder membrane, collodion membrane, ion exchange membrane, bipolar membrane. It is selected from membranes and the like, but any material that does not permeate colloidal particles but permeates water and inorganic anions may be used. This dialysis operation is preferably carried out for several hours or longer, and the progress of dialysis can be confirmed by pH or electric conductivity. Incidentally, due to the increase in pH accompanying dialysis, part of peroxotitanic acid is decomposed to generate bubbles of oxygen gas. In this case, it is preferable to remove the bubbles by aeration or the like.

In the step of removing contaminant ions in the production method of the present invention, the electrolytic treatment tank is partitioned by an ion exchange membrane, and the reaction product-containing aqueous liquid is placed in the electrolytic chamber for electrolysis. As the anion exchange membrane, it is preferable to use a strongly basic anion exchange membrane having acid resistance (for example, a membrane made of a styrene-based strongly basic resin). When the cation exchange membrane is used in combination with the anion exchange membrane, it is preferable to use a strongly acidic resin (for example, styrene resin). Platinum, platinum-coated titanium, or DSE is preferably used for the anode, platinum-coated titanium, stainless steel, or the like can be used for the cathode, and the current density in the electrolytic treatment is 0.1 to 10 A.
It is preferable to carry out in the range of / dm ² . The end of the treatment can be confirmed by measuring the pH or the electric conductivity of the purified aqueous liquid in the cathode chamber.

In the method of using an ion exchanger in the step of removing contaminant ions of the method of the present invention, it is most preferable to use an anion exchange resin mixed with a cation exchange resin at an appropriate ratio as the ion exchanger. In addition to these, zeolite, basic muscovite, hydrated iron oxide, hydrated zirconium oxide and the like can be used. The contact between the reaction product-containing aqueous liquid and the ion exchanger is carried out by directly adding the ion exchanger to the reaction product-containing aqueous liquid and stirring, and by using a column filled with the reaction product-containing aqueous liquid and the ion exchanger. It is possible to use any of the passing methods. Also in this case, the completion of the treatment is that the pH of the purified liquid is high,
Alternatively, it is performed by confirming that the electric conductivity is lowered.

As the titanium compound aqueous solution used in the method of the present invention, it is preferable to use one containing few impurities, and deionized water or distilled water from which hardness has been removed is preferably used as water used for dilution, neutralization and the like.

The ceramic coating material of the present invention contains as a main component a colloid of titanic acid or titanium oxide having an extremely fine particle size, and further contains peroxotitanic acid, contains almost no impurity ions, and contains a small amount of peroxotitanium. Since titanic acid enhances the stability of the sol, it does not gel even in a pH range close to neutral, and has a certain degree of viscosity, so a coating that is easy to apply, transparent, dense, and has good adhesion can be obtained. There is a feature called. Further, peroxotitanic acid is adsorbed on the surface of the titanium oxide colloidal particles and imparts a negative charge thereto, thereby preventing aggregation and precipitation of the colloidal particles and stabilizing them.

In the production method of the present invention, trivalent or tetravalent titanium ions are once converted into hexavalent titanium in peroxotitanic acid, and chlorine ions, sulfate ions, etc. are removed by anion removal steps such as dialysis and ion exchange. Only the contaminant ions are removed, and at the same time, fine colloidal particles of titanic acid or titanium oxide are produced.

In the method of the present invention, the reaction of titanium ion with hydrogen peroxide to once convert this into peroxotitanic acid, and then to form titanic acid or titanium oxide colloid is to use fine titanic acid or titanium oxide colloid. It is most important in producing particles. According to the conventional method in which particles of tetravalent titanium ions are precipitated by addition of an alkali or the like, the particles grow rapidly because the particles grow rapidly, and it is difficult to obtain a colloid of fine particles. It is possible to obtain a stable colloid of titanic acid by the method of converting the titanium ion into peroxotitanic acid and then precipitating the titanic acid or titanium oxide colloidal particles as described above. The coexistence of titanic acid improves markedly.

In the reaction at this time, when titanium trichloride is used as a raw material, the reaction for producing peroxotitanic acid is 2T.
iCl ₃ + 3H ₂ O ₂ + 4H ₂ O → 2H ₄ TiO ₅ +6
The generated HCl, which is represented by HCl, is removed by deionization treatment such as dialysis and ion exchanger treatment. The production of titanium dioxide or colloidal titanate is 2H ₄ TiO 2.
₅ → 2TiO ₂ + 4H ₂ O + O ₂ ↑
Excess hydrogen peroxide is decomposed and removed as oxygen and water.
Also, the peroxotitanic acid contained in the paint decomposes completely into titanium dioxide when the coating film is baked,
A highly pure titanium dioxide coating film is obtained.

Further, by subjecting the aqueous solution containing the reaction product to a heat treatment at a temperature of less than 100 ° C. before carrying out a treatment for removing contaminant ions such as dialysis or ion exchange, the titanium dioxide colloidal particles have an optimum particle diameter of 10 ^-1 to. Since it has a particle size of 10 ⁻⁴ μm, the transparency and adhesion of the coating film obtained from this paint can be significantly improved, and at the same time, the photocatalytic activity and the stability of the paint can be further enhanced.

[0040]

EXAMPLES The ceramic coating material of the present invention and the method for producing the same will be further described below with reference to examples.

Examples 1 to 4 To a 20% titanium trichloride aqueous solution, 31% hydrogen peroxide solution was added for sufficient reaction, and 1N caustic soda aqueous solution was added to this reaction system to adjust its pH value to 3. Then, the obtained yellow-orange reaction product-containing aqueous liquid was subjected to diffusion dialysis for 48 hours in running water using an RO membrane or a cellophane membrane as a semipermeable membrane. However, heat treatment was performed under the conditions shown in Table 1 before the diffusion dialysis. The obtained purified liquid was analyzed and tested by the method described in detail later.

Examples 5 to 7 The titanium tetrachloride solution was diluted with water and dilute hydrochloric acid and added to
Adjust the pH value to 2 by adding% ammonia water and add 3 to this.
After 1% hydrogen peroxide was added and sufficiently reacted, the obtained yellow-orange reaction product-containing aqueous liquid was subjected to heat treatment under the conditions shown in Table 1, and then this was subjected to anion exchange membrane (Selemion AMV type). : Asahi Glass Co., Ltd.) and a cation exchange membrane (Seremion CMV type, Asahi Glass Co., Ltd.) as the electrolytic solution of the electrolytic cell, and the current density using platinum-plated titanium plate as the cathode plate and the anode plate. Electrolysis was performed at 0.2-2 A / dm ² . After electrolysis, the catholyte was taken from the central electrolysis chamber and analyzed and tested.

Examples 8 to 9 A 30% titanium sulfate solution was diluted with water, and 31% hydrogen peroxide solution was added thereto for sufficient reaction. The obtained yellow-orange reaction product-containing aqueous liquids are shown in Table 1. A heat treatment was performed under the conditions described, and the liquid was mixed with an anion exchange resin and a cation exchange resin and sufficiently stirred, and then the purified liquid obtained by filtering this was analyzed and tested.

Comparative Examples 1 to 3 Comparative Example 1 contains a yellow-orange reaction product prepared in the same manner as in Example 1, Comparative Example 2 in the same manner as Example 5, and Comparative Example 3 in the same manner as Example 8. The aqueous liquid was used as a ceramic coating without any treatment for removing contaminant ions.

Comparative Example 4 A solution prepared by diluting a titanium tetrachloride solution with water was subjected to diffusion dialysis for 48 hours in running water using an RO membrane or cellophane paper as a semipermeable membrane, and this solution was analyzed as a ceramic coating solution. It was submitted to the test.

Analysis of coating composition (1) Peroxotitanic acid concentration The concentration of peroxotitanic acid in the solution was determined by adding sulfuric acid to the test solution to make it acidic, and using a spectrophotometer to measure the absorbance of the peroxotitanic acid complex at a wavelength of 430 nm. Measure, H ₄ TiO ₅
Converted to concentration. (2) Titanic acid concentration The titanic acid concentration is 50% by heating and evaporating the water content of the sample solution.
The mixture was heated at 0 ° C. for 2 hours to form titanium dioxide, and the weight obtained by subtracting the weight of peroxotitanic acid from the weight of the residue was used as H ₂ TiO ₃
Converted to.

Evaluation of coating film performance The prepared ceramic coating sample liquid was applied on a plate glass substrate to a thickness of about 1 μm, dried at 100 ° C., and then 500
Bake at ℃. The adhesiveness, transparency, and photocatalytic property of this coating film were measured or evaluated by the following methods. (1) Adhesion and Transparency The transparency of the coating film was visually determined, and the adhesion to the plate glass was peeled off after the cellophane tape was applied and the presence or absence of peeling was observed and evaluated. (2) Photocatalytic property The photocatalytic property was obtained by applying salad oil on the surface of a coating film of 10 cm x 3 cm, irradiating it with ultraviolet rays for 20 hours using a UV light (15 W), and then determining the amount of decomposition of the applied oil from the weight difference. Expressed by value.

Table 1 shows the production conditions, composition analysis values and coating film performance of the ceramic coatings used in the test.

[Table 1]

Table 1 shows that the ceramic paints of Examples 1 to 9 according to the present invention were excellent in adhesion, transparency and photocatalytic property. On the other hand, Comparative Examples 1 to 3 outside the scope of the present invention
The ceramic paint of No. 4 was unsatisfactory in any of these performances.

[0050]

The ceramic coating material of the present invention and the ceramic coating material produced by the method of the present invention form a titanium oxide coating film having good transparency and adhesion and good photocatalytic properties. . In the ceramic coating material of the present invention, the titanium oxide colloid is stabilized by peroxotitanic acid, and the coating film obtained by this coating material has excellent photocatalytic properties, and further has a stain adhesion preventing and decomposing effect, an antibacterial effect, a rust preventive effect, In addition, it is excellent in the effect of purifying air and water quality, and has a high practical utility value.

Claims (7)

[Claims] 1. A colloid of titanic acid or titanium oxide,
And a peroxotitanic acid, wherein the weight ratio of the H ₂ TiO ₃ conversion content of the titanic acid or titanium oxide colloid to the H ₄ TiO ₅ conversion content of the peroxotitanic acid is 20,000: A titanium oxide-based ceramic paint characterized by having a content of 1 to 500 and containing substantially no other ions. 2. A water-soluble titanium compound and a peroxide compound are reacted in water, and the resulting reaction product-containing aqueous liquid is subjected to a contaminant ion removing step.
The method for producing the titanium oxide-based ceramic coating material according to claim 1. 3. The production method according to claim 2, wherein in the step of removing contaminant ions, the reaction product-containing aqueous liquid is subjected to a dialysis treatment using a semipermeable membrane or an electrodialysis treatment. 4. In the step of removing contaminant ions, the reaction product-containing aqueous liquid is subjected to electrolytic treatment in an electrolytic cell in which a cathode chamber and an anode chamber are partitioned by an ion exchange membrane. Item 2. The manufacturing method according to Item 2. 5. The method according to claim 2, wherein in the step of removing contaminant ions, the reaction product-containing aqueous liquid is brought into contact with an ion exchange material. 6. The reaction product-containing aqueous liquid is subjected to a heat treatment, and then the contaminant ion removing step is performed.
The manufacturing method according to any one of claims 2 to 5. 7. The manufacturing method according to claim 6, wherein the heat treatment is performed at a temperature lower than 100 ° C.