JPH09235119A - Aqueous sol of low-active zirconia and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a stable aqueous sol of a low-active colloidal zirconia readily removable by washing with water even when adhesion occurs on the surface of a material such as a semiconductor. SOLUTION: This method for producing an aqueous sol comprises baking a raw material colloidal zirconia, having 10-400m<2> /g specific surface area and 20-500nm particle diameter and holding 4-15wt.% dehydrating moisture content at 400-1000 deg.C for 0.5-50hr, producing a baked zirconia powder holding 0.1-2wt.% dehydrating moisture content and pulverizing the resultant baked zirconia powder in water containing a water-soluble acid or alkali present therein. The resultant stable aqueous sol contains a colloidal zirconia, having 5-200m<2> /g specific surface area and 20-1500nm particle diameter and holding 0.1-3wt.% dehydrating moisture content at 5-80wt.% concentration.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a stable aqueous sol of low activity zirconia and a method for producing the same. In particular, the colloidal zirconia of this sol has a particle size of 20 to 1500 nm, and even if it adheres to the surface of the material, washing the material in water removes the adhered colloidal zirconia from the surface of the material. Shows low surface activity.

[0002]

2. Description of the Prior Art U.S. Pat.
And an average of 5 to 200 nm by electron microscope observation
Particle size (D), 5-4 measured by nitrogen gas adsorption method
00m ^Two Specific surface area / g and A × D = 1000 to 20
The ultimate colloidal zirconia particles with a relationship of 00
Certain acidic aqueous sols are disclosed. The sol is Jill
Heat the conium salt under pressure at a temperature of 120-300 ° C.
It is produced by a method of hydrolyzing the above salt.

JP-A-2-167826 discloses a stable alkaline aqueous sol of colloidal zirconia. The sol was prepared by adding a water-soluble organic compound having a hydroxyl group to an acidic aqueous sol of colloidal zirconia having a particle size of 50 nm, and then forming a sol having a pH of 6 to 14 in the produced sol. So that a basic compound is added.

The colloidal particles of zirconia in prior art sols associated with sols as disclosed in these references have been found when the surface of materials such as semiconductor materials is polished with the sols and then washed with water. , Adheres to the surface as colloidal particles and remains on the surface of the material, or when the sol comes into contact with the inside of the container, when the container is emptied and then washed with water, on the inner wall Remain as colloidal particles on the inner wall of the container.
Thus, prior art colloidal particles of zirconia are characterized by having a high surface activity or a highly active surface.

[0005]

One of the objects of the present invention is that when colloidal zirconia adheres to the surface of a material, it is easily removed from the surface by washing it with water or in water. A stable aqueous sol of colloidal zirconia having such low surface activity is provided.

Another object of the present invention is to provide a method for preparing stable aqueous sols of colloidal zirconia having such low surface activity.

[0007]

The stable aqueous sol of colloidal zirconia provided according to the present invention has a colloidal zirconia content of 5 to 5 measured by a nitrogen gas adsorption method.
It is a stable aqueous sol of colloidal zirconia having a specific surface area of 200 m ² / g and a particle size of 20 to 1500 nm measured by a dynamic light scattering method.

The characteristic of colloidal zirconia of the sol is that when the sol is dried at 150 ° C. for 3 hours to obtain a dry powder of colloidal zirconia, the dry powder is 1100 ° C. When heated for a period of time, 0.1 to 3% by weight of the dry powder due to dehydration
Is to show a weight loss of. In other words, the sol's colloidal zirconia carries 0.1 to 3% by weight of dehydratable water. The sol has colloidal zirconia as ZrO _{2 in} an amount of 5 to 80% by weight and is based on 1 mol of ZrO _{2 of} colloidal zirconia and 0.0
It has a water-soluble acid in an amount of 1-100 meq and a water-soluble alkali in an amount of 1-100 meq.

The method for producing a stable aqueous sol of colloidal zirconia according to the present invention has a specific surface area of 10 to 400 m ² / g and 2
Having a particle size of 0-500 nm and 4-15% by weight
4 of the colloidal zirconia that retains the dehydrating water of
A step of forming calcined zirconia having a dehydrating water content of 0.1 to 2 wt% by calcining at a temperature of 00 to 1000 ° C. for 0.05 to 50 hours; in an aqueous medium containing a water-soluble alkaline water-soluble acid or 1 to 100 milliequivalents of ZrO ₂ 1 mole per 0.01 to 100 milliequivalents, keeping the ZrO ₂ concentration of the calcined zirconia to 5-80% by weight,
It comprises a step of continuing pulverization until an aqueous sol of colloidal zirconia having a particle size 1 to 3 times the particle size of the above-mentioned pre-calcined colloidal zirconia is formed.

The colloidal zirconia used in the step of forming the calcined zirconia is derived from the raw material zirconia sol. The colloidal zirconia is dried at a temperature of 150 ° C. for 3 hours and then dried zirconia. When the powder is obtained, the dry powder is
When the dry powder is heated at 1100 ° C. for 1 hour, dehydration is characterized by a weight loss of 4 to 15% by weight of the dry powder. In other words, the sol's colloidal zirconia possesses 4-15% by weight of dehydratable water.

When the calcined zirconia is dried at a temperature of 150 ° C. for 3 hours to obtain a dry calcined zirconia powder, the dry powder is obtained by heating the dry powder at 1100 ° C. for 1 hour. It is characterized by showing a weight loss of 0.1 to 2% by weight of the dry powder due to dehydration. In other words, the calcined zirconia retains 0.1-2% by weight of dehydratable water prior to grinding.

The specific surface area of colloidal zirconia is measured by a conventional nitrogen gas adsorption method. Particle size of the colloidal zirconia is measured by a dynamic light scattering method by using a device named commercially available devices, for example, US Coulter (Coulter) manufactured by "N _4". The amount of water-soluble acid or water-soluble alkali contained in the sol, colloidal zirconia, colloidal zirconia powder, calcined zirconia and zirconia after heating at 1100 ° C. is measured by a chemical analysis known in the art. To be done.

The stable aqueous sol of colloidal zirconia of the present invention essentially comprises a raw material sol of colloidal zirconia or a raw material sol of colloidal zirconia, for example, from 80 to
A method comprising a step of calcining powdery colloidal zirconia obtained by drying at a temperature of 200 ° C., thereby forming calcined zirconia, and a step of pulverizing the calcined zirconia in water in the presence of an acid or an alkali. Manufactured.

The colloidal zirconia in the raw material sol is 10 to 400, preferably 20 to 300 and more preferably 20 to 500 m ² measured by a nitrogen gas adsorption method.
/ G specific surface area, and measured by dynamic light scattering 2
It may have a particle size of 0 to 500, preferably 50 to 400 and more preferably 70 to 300 nm. The colloidal zirconia of the raw material sol is obtained by drying the colloidal zirconia at a temperature of 150 ° C. for 3 hours to obtain a dry zirconia powder.
When the dry powder is heated at 1100 ° C. for 1 hour, dehydration is characterized by a weight loss of 4 to 15% by weight of the dry powder. In other words, the sol's colloidal zirconia possesses 4-15% by weight of dehydratable water.

The raw sol of colloidal zirconia may be prepared by methods known in the art, for example by heating a zirconium salt in an aqueous medium as disclosed in US Pat. No. 2,984,628. Is prepared by hydrolyzing the salt and forming colloidal zirconia in the medium. The raw material sol is a zirconium salt such as zirconium oxychloride, zirconium nitrate, zirconium sulfate or zirconium acetate at a zirconium ion concentration of 0.01 to 2 mol per liter of water at a temperature of 100 to 200 ° C. under pressure of 1 to 1. 100
It is preferably prepared by a method of heating over time, thereby forming an acidic aqueous sol of colloidal zirconia.

The purified type raw material sol can be produced by ultrafiltration of an acidic sol. The alkaline type raw material sol can be obtained by adding an alkaline substance to an acidic sol, which is disclosed in JP-A-2-167827. The colloidal zirconia can be used even in the form of large particles formed by agglomeration of those particles. For example, a slurry produced by adjusting the pH of a colloidal zirconia sol to a neutral range can also be used. Can be used.

Specific surface area of 10 to 400 m ² / g and 20 to
To form a colloidal zirconia powder with a particle size of 500 nm, the raw sol is dried in a dryer, preferably a spray dryer at 80-200 ° C, preferably 1
You may dry at 00-150 degreeC. The powder of colloidal zirconia loses weight when the powder is re-dried at higher temperatures, and the particles have higher temperatures at higher temperatures.
For example, even if it is fired at 500 ° C, the weight is further reduced.
However, the powder after heating at a temperature of 1100 ° C. does not lose weight after heating the powder again at a temperature above 1100 ° C. The decrease in the weight of the powder may be due not only to the release of water from the powder due to dehydration, but also to the release of volatile substances other than water, such as acids, alkalis or salts contained in the powder. Had been found.

The amount of water (H) that can be dehydrated from the raw material colloidal zirconia powder is determined by the weight (W ₁ ) of the powder after drying the powder at 150 ° C. for 3 hours and H ₂ O in the powder.
Other than the volatile components (C ₁ ) were measured, and the weight of the powder after heating the powder at 1100 ° C. for 1 hour (W ₂ ) and the weight of the volatile components other than H ₂ O in the powder ( C
₂ ) again, and the equation: H = (W ₁ −C ₁ ).
- obtained by determining H by (W ₂ -C _2). The amount of water that can be dehydrated from colloidal zirconia is
It is expressed in% by weight given by (H / W ₁ ) × 100.

The step of forming the calcined zirconia is obtained by calcining the raw sol or slurry in a vessel such as a ceramic or metal vessel in an electric or gas furnace, or preferably by drying the raw sol. The obtained colloidal zirconia is fired. Firing is 1-10 per minute
It is preferred to start by raising the temperature at a rate of ℃, and firing is 400-1000 ℃, preferably 50.
Carrying out at temperatures of 0-950 ° C and more preferably 600-900 ° C to form calcined zirconia. The calcined zirconia is dried at 150 ° C. for 3 hours to obtain a dry powder, and when the dried powder is then heated at 1100 ° C. for 1 hour, it is 0.1-2, preferably 0.1% based on the dry powder. 1-1.5 and more preferably 0.1-1%,
It has the characteristic of showing weight loss due to dehydration. In other words, the calcined zirconia is 0.1-2, preferably 0.1.
It has a dehydrating water content of ˜1.5, most preferably 0.1 to 1% by weight. It is preferred to complete the calcination at a temperature of 400 to 1000 ° C. within a time of 0.05 to 50 hours, and most preferred to complete the calcination at a higher temperature in a shorter time. The calcined zirconia is cooled to room temperature.

The amount (Q) of water dewatered from the calcined zirconia obtained by calcining is also as described above, ie, 15
Weight of calcined zirconia after drying at 0 ° C. for 3 hours (W ₃ ) and weight of volatile matter other than H ₂ O (C ₃ ) and 1
From the weight of zirconia (W ₄ ) after heating at 100 ° C. for 1 hour and the weight of volatile components other than H ₂ O (C ₄ ),
_{Equation: Q = (W 3 -C 3} ) - obtained according to (W ₄ -C _4). The amount of water dehydrated from the calcined zirconia is
Expressed in weight percent given by (Q / W ₃ ) × 100. Calcined zirconia has a lower specific surface area compared to the specific surface area of colloidal zirconia before calcining.

Then, the calcined zirconia is added to water for 5-8 times.
0, preferably 10-60 and more preferably 20-
Grind at a ZrO ₂ concentration of 50 wt% calcined zirconia. A stable sol of acidic colloidal zirconia is obtained by adding calcined zirconia to 0.01 to 100, preferably 0.03 to 50, and more preferably 0.05 to 30 mm based on 1 mol of ZrO _{2 in} the calcined zirconia. Obtained by milling in water containing an equivalent amount of water-soluble acid. The acidic sol has a pH of 1-6, preferably 2-6 and more preferably 3-6. A stable sol of alkaline colloidal zirconia is prepared by adding 1 to 100, preferably 3 to 50, and more preferably 5 to 30 milliequivalents of water-soluble alkali to 1 mol of ZrO _{2 in} the calcined zirconia. It is obtained by crushing in the water it contains. The alkaline sol has a p of 8 to 13.5, preferably 9 to 13 and more preferably 10 to 13.
Have H. Another stable sol of alkaline type colloidal zirconia is obtained by adding an alkaline substance to the acidic sol prepared as described above.

The water-soluble acid in the sol is an inorganic acid such as hydrogen chloride, nitric acid, sulfuric acid, an organic acid such as formic acid, acetic acid, oxalic acid, tartaric acid, citric acid, lactic acid or an acid salt thereof. Good. The water-soluble alkali in the sol is a hydroxide of a metal such as sodium, potassium or lithium, or a quaternary ammonium such as tetraethanolammonium, monoethyltriethanolammonium, tetramethylammonium or trimethylbenzylammonium. It may be an oxide, or an amine such as, for example, monoethanolamine, diethanolamine, triethanolamine, aminoethylethanolamine, N, N-dimethylethanolamine, N-methylethanolamine, monopropanolamine or morpholine, or ammonia. .

Grinding may also be carried out by adding additives of the type of water-soluble polymeric substances, such as xanthan gum, locust bean gum, guar gum, carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, polyvinyl alcohol, sodium. It may also be carried out in the presence of polyacrylates, polyethylene oxides etc. or polyhydric alcohols such as glycerin, propylene glycol, ethylene glycol etc.

The crushing may be carried out in a mill such as a ball mill, a sand mill or an attrition mill, and the particle size of colloidal zirconia before calcination is from 1 to 3.
Times, preferably 1 to 2.5 times and more preferably 1 to
Grinding is continued for a period of time until an aqueous sol of colloidal zirconia having a double particle size is formed. Grinding is completed, for example, in 20 to 100 hours when using a ball mill.

Water-soluble polymeric substances such as xanthan gum, locust bean gum or guar gum are used in order to form a preferred sol of colloidal zirconia with high viscosity. It is effective to add to the sol formed by crushing without crushing. The colloidal zirconia in the sol obtained after crushing is measured by the nitrogen gas adsorption method.
It has a specific surface area of 00 m ² / g and a particle size of 20 to 1500 nm measured by the dynamic light scattering method, and the colloidal zirconia in the sol is obtained by drying the sol at 150 ° C. for 3 hours. When a powder of zirconia is obtained, the powder is 0.1-3, preferably 0.1-2., Based on the colloidal zirconia powder when dehydrated by heating the powder at 1100 ° C. for 1 hour.
5 and more preferably exhibits a weight loss of 0.1 to 2% by weight. In other words, the colloidal zirconia in the product sol is 0.1-3, preferably 0.1-3.
It carries 2.5 and more preferably 0.1 to 2% by weight of water which can be dehydrated. The amount of water that can be dewatered from the powder when the powder is heated is obtained in the same manner as in the colloidal zirconia in the raw material sol described above.

The product sol is Zr containing colloidal zirconia.
As O ₂ in an amount of 5 to 80 wt%. And the sol is ZrO ₂ of colloidal zirconia in the sol.
It has a water-soluble acid in an amount of 0.01 to 100 meq, or a water-soluble alkali in an amount of 1 to 100 meq based on 1 mol. The colloidal zirconia in the sol obtained after grinding has a significantly lower surface activity than the colloidal zirconia in the raw material sol, and the sol is stable,
It has a ZrO ₂ concentration of 80% by weight and an acidic pH of 1-6 or an alkaline pH of 8-13.5.

The colloidal zirconia sol obtained after grinding can be purified, if desired, by deionizing the sol through an ion exchange resin or by ultrafiltration of the sol. US Patent 298462
Colloidal zirconia formed by a method comprising heating an aqueous solution of a zirconium salt at 120-150 ° C., as shown in No. 8, has a large value of A × D, such as 10,000, which Far above the upper limit of 2000 described in the US patent specification; and its colloidal zirconia has an average particle size, as measured by nitrogen gas adsorption method, by electron microscopy or by dynamic light scattering method. It was found that the colloidal zirconia formed by the method does not have a dense structure, and has been further found, because it has a much larger specific surface area than is calculated from the diameter. The colloidal zirconia formed by the method has a heavy weight due to dehydration from the colloidal zirconia when heated at a high temperature. A decrease, eg, about 7%, for example, zirconia after calcination at about 800 ° C. shows a specific surface area of the colloidal zirconia before calcination, even though the calcination hardly changes the particle size of the colloidal zirconia. It has a much lower specific surface area, and the colloidal zirconia formed by the method has a surface area where the colloidal zirconia adheres to the surface of the material, such as after polishing the surface with the colloidal zirconia. Has a high surface activity so that it is not removed from the surface even when washed in water.

The colloidal zirconia formed by such a conventional technique is the ultimate particle composed of fine particles of zirconia existing in an aggregated form.
The fine particles of zirconia have Z on the surface of the fine particles.
Having many OH groups attached to the r atom and the OH groups imparting high surface activity to the particles, and during firing of the colloidal zirconia some of the fine particles change to larger particles. It is believed that adjacent colloidal particles of zirconia are linked together and come together.

Therefore, in the present invention, the weight reduction of the colloidal zirconia resulting from the calcination is caused by the condensation reaction of the OH group bonded to the Zr atom, and the release of water formed by the dehydration reaction from the colloidal zirconia. What is that, its calcination causes the growth of fine particles of zirconia to larger particles, which have a low surface activity resulting from a significant reduction in the number of OH groups per unit weight of zirconia. However, the calcined zirconia formed by the calcination can be crushed by external mechanical force on the particles, but cannot be finely subdivided to the extent that particles smaller than the colloidal zirconia before the calcination are formed. Therefore, the calcination of the zirconia fine particles has a perfect bond having a chemical bond expressed as Zr-O-Zr. It is contemplated that not strong enough to form a child structure.

It is also believed that the acid or alkali present in the water during the milling process functions as a stabilizer for stably dispersing the particles of colloidal zirconia formed by milling in water.

[0031]

However, the preferred sols of colloidal zirconia are prepared according to the preferred methods of the present invention. Less than 10m ² / g or 400m ²
Raw colloidal zirconia with a specific surface area greater than / g is not preferred for use in the calcination. A specific surface area of less than 10 m ² / g does not give a stable sol product in the grinding process, and a specific surface area of more than 400 m ² / g gives a product of colloidal zirconia with low surface activity in the grinding process. Because there is no.

Colloidal zirconia having a particle size smaller than 20 nm or larger than 500 nm is not preferred for use in the calcination. Particle sizes smaller than 20 nm tend to cause sintering of zirconia during firing, and particle sizes larger than 500 nm are
This is because it tends to form a colloidal zirconia product that is unstablely precipitated in the sol product.

It is not preferred that the temperature at which the colloidal zirconia is fired is lower than 400 ° C or higher than 1000 ° C. At temperatures below 400 ° C, the milling process does not produce low surface activity colloidal zirconia products, and at temperatures above 1000 ° C, milling processes produce colloidal zirconia products that cannot be stably dispersed in sol products. Because it does. Higher than 900 ° C, especially 95
A calcination temperature higher than 0 ° C is disadvantageous because it produces a colloidal zirconia having a particle size largely deviated from the particle size of the pre-calcined colloidal zirconia in the crushing step, and lower than 600 ° C, particularly lower than 500 ° C. The firing temperature is disadvantageous because it gives colloidal zirconia exhibiting a dewatering weight loss of more than about 3% (in other words, more than about 3%) in the grinding process.

Baking times shorter than 0.05 hours or longer than 50 hours are not preferred. Because 0.05
Times shorter than hours are less reproducible in production and times longer than 50 hours have no additional benefit and reduce the efficiency of the process. Less than 0.1% or 2%
Calcined colloidal zirconia, which retains more dehydrating water, is not preferred. This is because colloidal zirconia products that can be stably dispersed in sol products cannot be obtained with a dehydrating water content of less than 0.1%, and colloids with low surface activity with a dehydrating water content of more than 2%. This is because a zirconia-like product cannot be obtained.

Acids of less than 0.01 milliequivalent or alkalis of less than 1 milliequivalent with respect to 1 mole of ZrO ₂ in the grinding step are not preferred. This is because that amount of acid or alkali does not adequately disperse the colloidal zirconia during milling. Z in the crushing process
Acids or alkalis greater than 100 milliequivalents per mole of rO ₂ do not give a stable sol product and the colloidal zirconia in the product tends to aggregate in the sol.

ZrO ₂ concentrations below 5% by weight or above 80% by weight in the grinding process are not preferred. Because sol products with concentrations less than 5% by weight usually require subsequent concentration, making the process inefficient, and concentrations above 80% by weight produce products in which the colloidal zirconia cannot be stably dispersed in the sol. Because it does. The crushing step cannot produce colloidal zirconia having a particle size smaller than that of the raw material sol. When colloidal zirconia having a particle size larger than 3 times the particle size of the colloidal zirconia in the raw material sol is produced in the pulverizing step, the colloidal zirconia tends to precipitate in the sol product.

[0037]

The present invention will be further described with reference to the following examples. These examples are not intended to limit the scope of the invention. Example 1 In this example, an acidic colloidal zirconia raw material sol (S ₁ ) and a colloidal zirconia powder (P ₁ ) are prepared.

An aqueous zirconium oxychloride solution is prepared by dissolving 1000 g of zirconium oxychloride in 2100 g of pure water. To the whole solution, stir 25
Add 264 g of% aqueous ammonia. The entire solution of zirconium oxychloride solution containing ammonia is heated in an autoclave at 130 ° C. for 7 hours, then the liquid in the autoclave is cooled to room temperature and collected.
The pH of the recovered liquid is 1 or less,
(Coulter) is an aqueous sol of colloidal zirconia having a particle size of 89 nm as measured by a dynamic light scattering method using an apparatus called "N ₄ ". The colloidal zirconia has a mean particle size of 100 nm in electron micrographs.

To 3200 g of recovered sol, 11.7 g of 25% aqueous ammonia is added to form an aqueous sol of colloidal zirconia having a pH of 5.2. Pure water is added to the colloidal zirconia at pH 5.2, and then the diluted sol is concentrated through an ultrafilter. A total of 28 kg of water is added to the sol during repeated dilution and ultrafiltration. as a result,
910 g of colloidal zirconia having a pH of 4.6, a ZrO ₂ concentration of 38% by weight, a Cl concentration of 0.88% by weight and an NH ₃ concentration of 0.1% by weight or less are obtained.

[0040] The sol (S _1), an inlet temperature of 190 ° C., dried in a spray drier outlet temperature 100 ° C., N ₂
A colloidal zirconia powder (P ₁ ) having a specific surface area of 128 m ² / g measured by the gas adsorption method is formed. Colloidal zirconia 100 (nm) x 128
The calculation of (m ² / g) gives a numerical value of 12800. The colloidal zirconia used in this experiment is described in US Patent No. 29846.
It has been found to have a threatening value of 12800, a value far exceeding the 2000 limit of 2000 shown in the 28 specification.

Powder (P₁ ) For 3 hours at 150 ° C
Dry in a drying oven. Chemical analysis of the powder after drying
It contains 2.28% by weight of Cl. Then drying
After that, 11.085 g of the powder is heated at a temperature of 1100 ° C. for 1 hour.
Heat in an electric furnace for a period of time. 10.150g heating
The latter zirconia powder is obtained. A chemical analysis shows that
The Cl content in the powder after heating is 0.01% or less. this
Colloidal zirconia due to weight loss of powder due to heating
Powder (P₁ ) Is powder (P ₁ ) At 150 ° C for 3 hours
Based on the powder prepared by drying over,
Heat the dried powder at 1100 ° C. for 1 hour
When found, 6.2% by weight of water is found to be dehydrated
Is done.

Example 2 In this example, an alkaline colloidal zirconia raw material sol (S ₂ ) and a colloidal zirconia powder (P 2
₂ ) Adjust. A purified sol of colloidal zirconia (S ₁ ) having a pH of 4.6 is prepared in the same manner as in Example 1.

To 1000 g of sol (S ₁ ) is added, with stirring, 31 g of citric acid and then 39 g of 25% aqueous ammonia. Pure water is added to the sol containing citric acid and ammonia, and then the diluted sol is concentrated through an ultrafilter. Total volume during repeated dilution and subsequent ultrafiltration 7.
Add 8 kg of pure water. 8.6 pH, 36 wt% ZrO ₂ concentration, 0.01 wt% or less Cl concentration, 2.5
Purified sol of colloidal zirconia (S ₂ ) 1 having a citric acid concentration of wt% and an NH ₃ concentration of 0.08 wt%
050 g are obtained. The colloidal zirconia in the sol has a particle size of 104 nm measured with the device N ₄ .

[0044] The sol (S _2), an inlet temperature of 190 ° C., dried in a spray drier outlet temperature 100 ° C., N ₂
A colloidal zirconia powder (P ₂ ) having a specific surface area of 135 m ² / g measured by the gas adsorption method is obtained. The powder (P ₂ ) is dried in an oven at 150 ° C. for 3 hours. The powder after drying was 6.88 according to chemical analysis.
It has a citric acid content of less than 0.01% by weight, a Cl content of less than 0.01% by weight and an NH ₃ content of less than 0.01% by weight. Then, 11.713 g of the dried powder was added to 1 at a temperature of 1100 ° C.
Heat in electric furnace over time. After heating 10.16
2 g of zirconia powder is obtained. The obtained powder is 0.0
It contains citric acid in an amount less than 1% by weight or less.

The colloidal zirconia powder (P ₂ ) is
Based on the powder prepared by drying the powder (P ₂ ) at 150 ° C. for 3 hours, when the dried powder is heated at 1100 ° C. for 1 hour, 6.4% by weight of water is dehydrated. Is found to have been done. Example 3 In this example, colloidal zirconia powder (P ₂ ) was calcined under various conditions to form calcined zirconia,
Then, the calcined zirconia is ground in water.

The powder (P ₂ ) is fired in an electric furnace at the temperature and time shown in Table 1 to form fired zirconia (T ₁ ) to (T ₆ ) (T ₆ is a comparative example). Let Zirconia (T ₁ ) contains 30 ppm (by weight) of Cl according to chemical analysis. Zirconia (T ₁ ) to (T
₆ ) Measure the specific surface area (m ² / g) for each,
Then, the weight reduction rate (dehydration amount,%) of each of the zirconia (T ₁ ) to (T ₆ ) is determined by the same method as described above, that is, the calcined zirconia (T ₁ ) to (T ₆ ).
₆ ) was dried at 150 ° C. for 3 hours and then 1100
Obtained by a method of heating at ℃ for 1 hour. The results are shown in Table 1.

[0047]

[Table 1] Table 1 ───────────────────────────────── Firing temperature Time Specific surface area Dehydration amount Zirconia (℃ ) (hr) (m ² / g) (%) ───────────────────────────────── T ₁ 500 0.1 60.5 1.2 T ₂ 750 2 20.1 0.35 T ₃ 950 2 14.8 0.16 T ₄ 500 0.1 60.5 1.2 T ₅ 500 0.1 60.5 1.2 T ₆ 1200 2 4.8 0.1 or less ───────────────── ──────────────── By dissolving high-purity hydrochloric acid in pure water, 204 g of a hydrogen chloride aqueous solution containing 0.2 meq of HCl is prepared.

Next, 96 g of zirconia (T ₁ ), 204 g of adjusted hydrogen chloride aqueous solution and 700 g of hard beads made of zirconia having a diameter of 5 mm are put into a ball mill having a diameter of 8 cm. The mill is sealed and rotated at a speed of 200 rpm for 92 hours. From the mill to 5.4
A stable aqueous sol of colloidal zirconia (Z ₁ ) having a pH of 3 and a ZrO 2 concentration of 31% by weight is recovered.

The particle size of the colloidal zirconia in the sol (Z ₁ ) is 152 nm as measured by the device N ₄ . The sol (Z ₁ ) was heated at an inlet temperature of 190 ° C. and an outlet temperature of 10
Dry in a spray dryer at 0 ° C to obtain a colloidal zirconia powder. The powder exhibits a specific surface area of 61.8 m ² / g as measured by the N ₂ gas adsorption method.

This mill pulverization was carried out by firing 152 calcinated zirconia.
Milling to colloidal zirconia with a particle size of nm
Bring, but sol (Z₁ ) Of colloidal zirconia
61.8m^Two The specific surface area of / g is calculated by calcining zirconia (T₁ )
60.5m^Two Almost changed compared to the specific surface area of / g
Of the sol (S
_Two ) Of colloidal zirconia with a particle size of 104 nm
It is recognized that it is 1.5 times.

The powder having a specific surface area of 61.8 m ² / g is then dried in an oven at 150 ° C. for 3 hours. The powder after drying contains 0.1% by weight or less of citric acid according to chemical analysis. 110.447 g of powder
By heating at 0 ° C. for 1 hour, 10.173 g of zirconia after heating is obtained. The colloidal zirconia in the sol (Z ₁ ) is based on the colloidal zirconia powder prepared by drying the powder obtained in a spray dryer at 150 ° C. for 3 hours.
When the dried powder is heated at 1100 ° C. for 1 hour, 2.6% by weight of water is found to be dehydrated.

Example 4 In the same manner as in Example 3, each of the calcined zirconia (T ₂ ) to (T ₆ ) was ground in water in the presence of a milliequivalent amount of acid or alkali shown in Table 2. To do. Zirconia (T
Stable aqueous sols (Z ₂ ) to (Z ₅ ) were obtained from ₂ ) to (T ₅ ), while an aqueous slurry was obtained from zirconia (T ₆ ). The specific surface area of the colloidal zirconia in each sol is almost unchanged compared to that of the corresponding zirconia (T ₂ ) to (T ₅ ). The specific surface area of zirconia in the slurry produced by pulverizing zirconia (T ₆ ) is 7.2 m ² / g,
Slightly larger than 4.8 m ² / g of zirconia (T ₆ ).

The particle size of the colloidal zirconia in each sol was measured by instrument N ₄ and is listed in Table 2. The amount of dewatered water from each of the colloidal zirconia in the sol and the zirconia in the slurry formed by milling was determined as in Example 3 and is listed in Table 2.

[0054]

[Table 2] Table 2 ─────────────────────────────────── Product Calcination Acid or alkali Particle size Dehydration amount Zirconia (milliequivalent) (nm) (%) ─────────────────────────────────── Z ₁ T ₁ HCl 0.2 152 2.6 Z ₂ T ₂ HCl 0.2 190 0.81 Z ₃ T ₃ HCl 0.2 213 0.56 Z ₄ T ₄ HNO ₃ 0.2 163 2.5 Z ₅ T ₅ KOH 10.2 212 2.6 Slurry T ₆ HCl 0.2-0.1 or less ─── ──────────────────────────────── Example 5 In this example, from sol (Z ₁ ) to colloidal zirconia Adjust the alkaline sol.

Sol prepared in the same manner as in Example 3 (Z
₁ ) To 1000 g, 1000 g of pure water is added to prepare a diluted sol of colloidal zirconia having a ZrO ₂ concentration of 15% by weight. Then 36 g of an aqueous solution of potassium hydroxide having a concentration of 5% by weight are added to the total amount of the diluted sol, and the resulting sol is vigorously stirred for 4 hours at room temperature. A stable alkaline sol of colloidal zirconia having a pH of 10.4 is obtained. 20% by weight of ZrO by distilling off water from a sol having a pH of 10.4
A concentrated sol of colloidal zirconia having ₂ concentrations is prepared.

Example 6 In this example, the surface activity of colloidal zirconia in a sol (Z ₃ ) is tested in comparison with a control of the raw sol (S ₁ ). Each of the sol (Z ₃ ) and the sol (S ₁ ) was applied on the surface of a transparent glass plate having a length of 7.5 cm and a width of 2.5 cm and dried in an indoor environment, and colloidal zirconia was applied to the glass plate. Adhere on surface.

Next, the vibration frequency is 28 kHz (kilohertz).
Tsu), add ultrasonic waves with an output of 210 W to water and
The above glass plate is immersed at room temperature for 60 minutes. Sol
(Z_Three ) From the attached colloidal zirconia is glass
Although it is removed from the surface, the sol (S ₁ ) Attached from inside
Colloidal zirconia hardly falls off the glass plate.

[0058]

The stable aqueous sol of colloidal zirconia of the present invention may be acidic or alkaline, may contain water-soluble organic additives, and may be supplied as an industrial product. The sol is contained in various fields, such as binders for producing heat-resistant reinforced molds for use in precision casting, in aqueous media for waterjet cutting materials such as metals, ceramics or concrete. The present invention can be applied to various polishing agents, or polishing agents for polishing the surface of various materials roughly, precisely, or mirror-likely.

The sol is a surface of a semiconductor such as a semiconductor, for example, silicon, germanium or a compound of III-V group, II-VI group or I-VII group type; lens, prism, cathode ray tube, mask for IC or LSI, etc. Optical glass; crystallized glass, alkali-free glass, low-alkali glass, quartz glass, silicate glass, borate glass, phosphate glass, germanate glass, tungstate glass, molybdate glass, tellurium Glass, borosilicate glass, aluminosilicate glass, aluminoborate glass, fluoride glass, fluorophosphate glass, oxyhalide glass, oxynitride glass, chalcogenide glass, metallic glass; for use in optical fibers Quartz glass, glass for use in liquid crystal cells,
Surface of lithium niobate or lithium tantalate for use in optical ceramics; surface of crystal, aluminum nitride, alumina, ferrite or zirconia for use in parts of electronic or electrical products; interlayer insulating film in multilayer wiring semiconductor device, And the surface of metal wiring such as aluminum, copper, tungsten or alloys thereof; Ni provided on a substrate such as a disk for magnetic recording medium
-P or other plating layer surface, especially Ni 90-92% and P8
Surface of hard Ni-P plating layer having composition of -10%, surface of aluminum oxide layer or substrate surface of aluminum, its alloy, alumite, glass, glass carbon, etc .; and surface of cemented carbide such as tungsten carbide; Furthermore, it is clearly useful for polishing the surface of hard plastics such as polysulfone, polycarbonate, nylon. The colloidal zirconia sol of the present invention is used by adding a nitrate, an organic acid, a metal soap, a chelate compound, gluconic acid, sulfamic acid, an amine salt, hydrogen peroxide solution, hypochlorite, etc., if desired. Can be used and is further useful as an abrasive.

The colloidal zirconia sol of the present invention is
As long as the charge on the surface of the colloidal particles of the sol of other metal oxides other than Zr is the same as that of the colloidal particles of zirconia, at the desired ratio with the sol of other metal oxides other than Zr. For example, 10 to 90 parts by weight may be mixed with 100 parts by weight of zirconia. Thus, for example, by mixing an alkaline colloidal zirconia aqueous sol with an alkaline colloidal silica aqueous sol or an acidic colloidal zirconia with an acidic colloidal alumina aqueous sol, a mixed sol is obtained. can get.

The mixed sol is also useful for polishing the surface of various materials or substrates as described above. Then, the mixed sol can be used by adding a nitrate, an organic acid, a metal soap, a chelate compound, gluconic acid, sulfamic acid, an amine salt, a hydrogen peroxide solution, hypochlorite, etc., if desired. It is further useful as an abrasive.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroaki Tanaka 3-7-1 Kandanishiki-cho, Chiyoda-ku, Tokyo Nissan Chemical Industries, Ltd.

Claims (4)

[Claims] 1. A specific surface area of 5 to 200 m ² / g and 20 to
Having a particle size of 1500 nm and 0.1-3% by weight
Dehydrating water-containing colloidal zirconia as its ZrO _{2 in} a concentration of 5 to 80% by weight, and 0.1 mol / mol ZrO _{2 of} this colloidal zirconia.
A stable aqueous sol of colloidal zirconia further containing 01-100 meq of water-soluble acid. 2. 10 to 400 m^Two / G specific surface area and 20
Having a particle size of ~ 500 nm and of 4-15% by weight
40% of colloidal zirconia which has dehydrating water
Baking at a temperature of 0 to 1000 ° C. for 0.05 to 50 hours
And retains 0.1 to 2% by weight of dehydratable water.
Step of forming calcined zirconia, and the above calcined zirconia
ZirO of this calcined zirconia_Two Per mole
Aqueous medium containing 0.01-100 milliequivalents of water-soluble acid
Medium, ZrO of the above calcined zirconia _Two Concentration 5 to 80 weight
%, The particle size of the above-mentioned colloidal zirconia before firing
Water of colloidal zirconia having a particle size 1 to 3 times larger than
Claims consisting of continuing milling until a reactive sol is formed
Item 2. A stable aqueous sol of colloidal zirconia according to Item 1.
Production method. 3. A specific surface area of 5 to 200 m ² / g and 20 to
Having a particle size of 1500 nm and 0.1-3% by weight
Dehydrating water-containing colloidal zirconia as its ZrO _{2 in} a concentration of 5 to 80% by weight, and 1 to 1 mol of ZrO _{2 of} this colloidal zirconia.
A stable aqueous sol of colloidal zirconia further containing a water-soluble alkali in an amount of 100 meq. 4. The step of forming the calcined zirconia according to claim 2, and the calcined zirconia obtained in this step are 1 to 1 per 1 mol of ZrO _{2 of the} calcined zirconia.
In an aqueous medium containing 100 milliequivalents of a water-soluble alkali, the ZrO ₂ concentration of the calcined zirconia was maintained at 5 to 80% by weight, and the particle size of the pre-calcined colloidal zirconia was from 1 to
The method for producing a stable aqueous sol of colloidal zirconia according to claim 3, which comprises a step of continuing pulverization until an aqueous sol of colloidal zirconia having a particle size of 3 times is formed.