JPH03503045A - Method for producing monodispersed titania spheres - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Chinia's +l・announcement Bu1 and another anus The present invention uses single-dimensional or monodisperse titania spherules as particles to form an additive for particle size control. using sol-gel chemistry to obtain high yields of the desired material. Regarding the method.

More particularly, the present invention provides a method for preparing titanium aluminum in the presence of an amine-containing particle size control additive. By hydrolysis of coxide, monodisperse spherical titania can be produced with good reproducibility and narrow particle size. It relates to a method of manufacturing in a limited manner.

Hikari summer evening view Ceramic materials offer a wide range of physicochemical properties, which depend on their unique atomic structure and microscopic properties. Depends on fine structure. Because of its fire resistance and chemical inertness, this material Enables use in environments where existing materials, such as sub-materials, do not last long. However, Its potential for growth in new application areas is high.1 Practical use requires high-performance Fulfills purity, strength, materiality and microstructural requirements for lamic applications. is not satisfied.

Conventional typical manufacturing methods for high value ceramic products result in the production of defective products that do not meet specifications. Costs are estimated to be as much as 25 to 75% of the manufacturing cost of a particular item. ing. These products reflect processes using traditional ceramic powders and manufacturing techniques. The numbers are clearly unacceptable and The current constraint on the highly technical use of It is a direct result of physicochemical properties. Average particle size, particle size distribution, and coagulation of raw material powder The degree of aggregation and dispersion properties combine to improve the green and final firing of the ceramic. It limits the microscopic materiality of the condensed state. Materiality in the microstructure of ceramics These properties are optimized by processing the powder under tightly controlled conditions. Become. Monodisperse metal oxide powder obtained by the sol-gel method has this morphology. It is the best example of this material.

Monodisperse metal oxide powders offer many process advantages over traditional ceramic powders. I can do it. The spherical shape and narrow point of particle size distribution of monodisperse powders make green ceramics allows tight control over the loading of powder particles in the container. Fewer aggregates are scratched , the particle packing is very uniform and the residual pore size in the green ceramic is It is often two pieces in diameter (1 micron or less).

As a result, residual pore sizes are often on the order of the diameter of a single particle. 1mi Chronic (or larger) residual pores and agglomerates are present in the fired ceramic structure. If present, it may cause cracks and defects in the material, reducing overall performance and strength. This is an extremely important advantage. In conventional ceramic powder processing to remove residual porosity and defects resulting from insufficient powder packing or agglomerates. It is very difficult to perform this by applying pressure and Addition of sintering aids for grain growth is a typical method. Pressure during high temperature processing It is not desirable to add a tA bonding agent because it is extremely costly. This is also undesirable for particles of a single dimension, since it adversely affects the high temperature properties of processing is not necessary to achieve density, microstructural symmetry, and sinterability. .

In addition to giving a more homogeneous green microstructure, monodisperse powders It has special advantages over traditional powders when firing ceramics. Sintering Since temperature is inversely proportional to particle size, the submicron diameter of the powder particles will affect the sintering of the material. They often reduce the temperature required for condensation by several hundred degrees. Tightly controlled particle size Therefore, the problem of non-uniform sintering that occurs with conventional powders, i.e. small particles that scrape In the compact, sintering does not start before the large particles. became. This often leads to undesirable large particle growth, particle size distribution and porosity. This method can have dire consequences on the performance and properties of ceramic materials.

For single-dimensional powders, the sintering of the powder particles is fast and spatially symmetrical, so that the particles in the sintered product are The fine structure of the child becomes symmetrical. Since the material is made from sol/gel, it can be baked as needed. Coagulation aids can be inexpensively and uniformly included in the synthesis process, and powder composition can be tightly controlled. Ru. This single-dimensional powder offers unique opportunities for control over many process variables; This defines the performance and application of ceramic products.

Studies have shown that aging of metal oxide particles affects powder surface area and microporosity. have a huge impact. Appropriate controls during the manufacturing process ensure that adsorbents, gas permeable membranes and and biological support materials, scanning electron microscopy assay materials, high strength structural ceramics and Powder with controlled micro and macro porosity, very useful as a substrate At present, titania is used for oxygen sensors, electronic components, etc. Widely used in the production of pigments.

U.S. Pat. No. 4,543,341 reports the route of monodisperse powders by sol-gel method. There is. This research is attributable to a resurgence of interest in sol-gel chemistry and the ability of this material to be manufactured using conventional methods. has generated a great deal of excitement due to its numerous advantages over ceramic powders.

In this early work, a synthetic method for producing monodisperse silica from alkoxides was developed for titanium. It was changed and expanded to include aluminum and zirconia.

U.S. Pat. The synthesis and characterization of the following titania powders are described. The production of powder is Mix equal amounts of tantetraethoxide ethanol solution and water, and stir for a short time. It will be done. Isolation of the powder must be done within 30 minutes after settling begins. , otherwise hard necked agglomerates of individual particles -gregates) is generated. The isolation method was just created. The powder is centrifuged at low speed and then sol decanethisilane. The powder is ethano The surface of the titania particles is given a negative charge by washing with water and alkaline water. This creates a net interparticle repulsion potential that inhibits powder agglomeration. Ru.

1 Omega dish! It is therefore an object of the present invention to produce titania monodisperse spheroidal bodies as molded compacts and provides a method for producing reproducibly as a dispersion in a suitable fluid medium. be.

Another object of the invention is to form titania spheroids into individual grains in the range of about 0.1-1 microns. In addition, the particle size distribution standard is approximately 172 mm of the average particle size, i.e. monodisperse or One provision is defined as a single size.

In one aspect, one embodiment of the invention produces a precipitate of titanium tetraathania. This can be seen in the manufacturing process of monodispersed titania, which consists of the following steps:

Another embodiment of the invention is to use basic water or titanium alkoxide based sols. production of monodisperse titania particles by aging a dispersion of said titania in a medium such as Found in the process of increasing internal porosity.

Still other aspects of the invention include adding the dispersion of chikunia particles to a porous mold and green body compact consisting of recovery of said solid green body compact from the mold of This can be seen in the manufacturing method of impact.

Other objects and embodiments are found in the following more detailed description of the invention.

Main plate Kohai Toyosei Shusho The present invention deals with the production of monodispersed titanium from an alcoholic solution of titanium tetraalkoxide. For the production of titanium alcohol particles using an amine-containing additive and water. The desired titania particles are produced by hydrolyzing the oxide solution and subsequently the monodisperse A solution of titanium ethoxide is dissolved in ethanol, secondary butylamine is added, Aqueous methanol is then added to the resulting solution to produce the desired monodisperse titania particles. to be accomplished. The particles can be separated and recovered from the solution to form a spherical solid. desired hydroxypropyl, alkoxide or alcohol when mixed with water. Cellulose may also be added. However, it is preferable to add it to a mixture of alcohol and water. stomach. Furthermore, after the monodispersed titania particles are redispersed in a redispersion medium, the titania particles are Collect as a dispersion.

Redispersion of monodispersed titania powder can be accomplished by any method known to those skilled in the art. However, it is preferable to use a vibrassometer manufactured by Sonics Materials, for example. High frequency sonic device (sonication d) such as Vibra Ce1l evice) and a dispersant selected from the mids.

Depending on the type of dispersion medium chosen and the powder loading (wt%) in the medium, the redispersion There are various uses for these materials. The redispersed material is then injected into a porous mold. Compacts and green body ceramics are made, then the material is tape It is molded into a shape and left to stand slowly to form an evenly packaged green ceramic. or the material is p) a salt preferably using ammonium hydroxide in the I range 8-11. Aged for 1-14 days in a basic water-like medium. The aging conditions are 15 The temperature of the product is from 1 to 90°C and the pressure is from 1 to 10 atmospheres. The increase in surface area is due to aging, whereas the surface area of the product is 5n (/g). The product increases to approximately 200 T'If/g.

The titania tetraalkoxide used in the present invention has the chemical formula Ti (OR) a ( R is a lower alkyl group having 1-4 carbon atoms) is Examples include, but are not limited to, dibenium tetramethoxide, titanium tetramethoxide, Thoraethoxide, titanium tetrapropoxide, titanium tetrabutoxide Sid, titanium tetraalkoxide, titanium isopropoxide, titanium titanium methoxytriethoxide, titanium ethoxypropoxybutoxide , titanium dimethoxyjethoxide and titanium methoxyethoxyp selected from the group of lopoxybutoxides.

Alcohols (ROH) of the present invention include, but are not limited to, methanol, ethanol, Tanol, 1-propertool, 1-butanol, 2-propertool, 2-butano 2-methyl-2-propanol. Alco with chemical formula ROH It is important that the R group in the group is selected from lower alkyl groups having 1 to 4 carbon atoms.

In the present invention, the alcohol solution of titanium tetraalkoxide is 0.05 Desirably, the concentration ranges from 1.0 molar to 1.0 molar.

The water content of the final hydrolysis mixture should not exceed a molar concentration of 0.2 to 1.5H. , and the initial alcohol solution has a concentration of less than 500 ppm (preferably 200 ρpi). It is important that it is not above. Furthermore, titanium tetraalkoxide alcohol The water content is preferably 100 to 300 pp.

The present invention provides a new particle size for producing single-sized titania by sol-gel chemistry. Concerning control additive systems. Secondary amines and diethylamine/hydroxy Propyl cellulose is one of the two preferred additive systems and powder during precipitation/production. In addition to preventing agglomeration of powder particles, hydrolysis of titanium alkoxide A monodisperse spherical powder is produced immediately.

This method is much superior to the known method. In typical examples, 0.001 to 0.1M used in an amount sufficient to form a solution containing

The widest range, 'd9, includes amines with alkyl groups of 1 to 7 carbon atoms in length. makes the process of this invention effective. Hydroxypropylene gives the best results. Special grade without lopyl cellulose (RPC) is the best among mono- or di-substituted amines. However, trialkylamines give the best results in the presence of HPC. give fruit. It is also true to use not only individual amines but also mixtures of amines. within the scope of the invention.

The mono- and di-substituted amines of the present invention include, but are not limited to, ethyl alcohol. amine, diethylamine, methylamine, dimethylamine, propylamine, dipropylene Lopylamine, butylamine, dibutylamine, pentylamine, diisothyla hexylamine, diethylamine, heptylamine, diethylamine, Sopropylamine, diisopropylamine, isobutylamine, diisobutylamine amine, 5ec-butylamine, di-5ec-butylamine, tert-butylamine amine, di-tert-butylamine, isopentylamine, tert-heptylamine selected from the group such as ethylpropylamine, hexylbutylamine, and others It will be done.

The trialkylamines of the present invention include, but are not limited to, triethyl amines. Trimethylamine, Triisopropylamine, Tributylamine, Trimethylamine, Trimethylamine, Triisopropylamine, Tributylamine sobutylamine, tri-5ec-butylamine, tri-tert-butylamine , tripentylamine, triisopentylamine, trihexylamine, trihexylamine butylamine, methyldiethylamine, ethylmethylpropylamine, propyl Diethylamine, hexylmethylpentylamine, propyl ethylbutylamine amine, pentyldibutylamine, and others.

The standard deviation of the charcoal distribution is 1/2 or less of the average particle size.

In a preferred embodiment, the 5ec-butylamine concentration is between about 0.001H and 0.001H. The concentration of triethylamine should be in the range of 1M to 0.001M. ．． range of 1M, and the concentration of hydroxypropyl cellulose contains alkoxides. As a basis it should be between 0.5 and 5% by weight. Alternatively, triethylamine The amine such as is present in the range of about 1 to 6 mole percent based on the titanium metal. Can be done.

These amine additives increase the relative sparseness of the powder particles. In addition to controlling the average particle size of the precipitated powder, It is valid. By simply changing the concentration of amine-containing additives, the fine particle size of the powder can be improved. The average particle size of the titania particles increases or decreases while maintaining the distribution. This particle size change is caused by water Although the concentration of both alkoxide reagents (and other reaction media) is constant, is a fundamental advance in the manufacture of these materials.

Particle size control additives are critical to the success of the reaction scheme of this invention. , its role in the process is unclear.

Unlike the well-understood organic polymerization reactions, the inorganic polymerization chemistry of metal alkoxides is extremely complicated. It's complicated. The structure of many metal alkoxides is such that they form oligomers in solution. It is not clear because it exists as a mixture. Various types of oligomers present in solution The sesame ratio depends on distillation, the presence of Lewis bases such as alcohols and amines, and It depends on the process of its synthesis. The presence of a small amount of water also causes metal narcoxide oligomers. influence not only the molecular structure and composition of the compounds, but also the relative rates of hydrolysis of those compounds. give a sound. What emerges from this huge variable matrix is a monodisperse metal acid is an extremely complex complex chemical system that constitutes the starting material for the synthesis of compound powders. . In this way, the development of the dosing system described herein makes it possible to This enabled the reproducible synthesis of monodisperse titania powder from crude starting materials.

In the synthesis of monodisperse powders using sol-gel technology, the nucleation and growth of particle formation are Several important criteria need to be met at this stage. most in this process An important factor is the homogeneity of the solution. Forming monodisperse powders by solution precipitation techniques For this to occur, uniform nucleation and grain growth must occur; therefore, prior to precipitation, nucleation The forming site needs to be removed from the solvent. These removals are typically submicron The reagent solution is passed through a filter (millibore), thus serving as a nucleation site. This function effectively removes heterogeneous precipitates.

In the hydrolysis reaction of metal alkoxides, this reaction results in rapid growth and precipitation of the material. Proceeds at a rate sufficient to ensure sludge, yet not so fast as to precipitate immediately upon addition of reagent. It is especially important that it is not fast. If the reaction is extremely fast, the local supersaturation It spreads into the sol, with the concomitant formation of non-uniform precipitates. Therefore, the solution Uniform with no local supersaturation, particle growth continues at some rate following initial precipitation. It must proceed with this.

Another point that should be incorporated into a successful reaction plan is that during particle growth in the sol, This is due to the irreproducibility of titania's chemical reactions. This is a very important factor.

At the beginning of particle growth, the particle surface has sufficient charge or there is a gap between the particles. The force is repulsive and the material is sterically stabilized to the extent that it prevents the formation of a strong coagulum. For powders synthesized under pH conditions close to the zeta potential of metal oxides, However, unless stabilized in some way, a concentrated dispersion of powder will Regarding the “agglomeration” process (flocculation) (precipitation of material in clusters of flocculated particles) occurs. child These points must be resolved in order to synthesize titania powder from alkoxides with good reproducibility. This is a major issue that must be addressed.

The method of the present invention involves mixing titanium tetraalkoxide with alcohol in a suitable container. Batch method by mixing and then adding amine-containing additives and hydroalcoholic medium It can be carried out with

After mixing for a suitable period of time, the monodisperse titania particles formed are separated from the reaction mixture; Wash with a suitable washing medium and recover as solid particles.

Separation and recovery of monodisperse titania particles can be achieved using gravity, standstill, batch or batch methods known in the industry. or by methods involving continuous centrifugation and filtration. The precipitation time is approx. A range of 0.1 to 30 minutes is desirable.

The selection of the redispersion medium is not limited to this, but ketones, water, carbon atoms of 1 -4 alcohols, aldehydes, chlorinated hydrocarbons, carboxylic acids, amines , and solutions of acids or bases.

Prior to the final separation of the monodisperse powder from the liquid, the reaction liquid is separated to form the powder body. contains (but is not limited to) water and alcohols containing 1-4 carbon atoms. I got stuck several times with the liquid I chose from the group.

In contrast, the precipitation reaction is carried out in a continuous operation. When performing this type of operation, of solution A consisting of nium tetraalkoxide, ethanol and amine additive. A certain amount is prepared by continuous method from its component chemicals, placed in a suitable container and subjected to appropriate temperature and stress. 0 reactor added to a volume of B solution consisting of water and ethanol maintained in a suitable working medium. After mixing in the reaction vessel for a suitable period of time, the effluent is continuously removed and separated using conventional separation methods. Separated by steps. At this time, the desired titania powder was collected and taken out. The liquid can be recycled if desired.

Monodisperse titania particles correspond to a standard deviation of the particle size distribution that is less than 1 part of the average particle size. manufactured with a relatively narrow particle size distribution.

On the other hand, in the conventional method, the particle size significantly exceeds 1 micron, the uniformity is poor, and the particle size exceeds 1 micron. The standard deviation is not less than the average particle size. The present invention has a particle size of 0.1 to 1.0 microns. The homogeneous spherical particles of Chron, in contrast to those produced in experiments with conventional methods, are The particles are manufactured to have a particle size of 1 micron or more. obtained using the method of the present invention The well-defined spherical shape and narrow particle size range of Cera Green body compact with high density and microstructural uniformity in the mink industry The long-held desire for a powder that could be used to create a powder was realized.

In contrast to published literature, titania particles obtained by methods known from the literature are reproducible. According to scanning electron microscopy (SEM), the products of the known method are ・1.2 microns as measured by Northrop Small Particle Analyzer (SPA) It is a highly aggregated agglomeration of particles with an average particle size of 1. This previous method was 0.3-0 ．． reported a particle size of 7 microns, but this method can be broadly and deeply replicated. However, the resulting particles were 1.2 microns in diameter, hard and intertwined. It is an inseparable aggregate made up of spherical 0.3 micron titania particles. there was.

In this specification and claims, the term "compact" is defined as Obtained by porous molds with dispersions of non-redispersed titania and monodispersed titania. or molded solid titania obtained by other molding methods known to those skilled in the art. This includes: Also, the word "Green Body J" refers to unfired pre-ceramic Define compact to mean compact.

Although the following examples are provided for illustrative purposes, they are not intended to be illustrative in nature. It should be understood that the present invention is not necessarily limited to these. I want to be.

stop comparison banto In order to distinguish the present invention from conventional patents, products must be made using methods described in the literature. Ta.

Titanium tetraethoxide was purchased from three different manufacturers and vacuum distilled. and carefully handled under inert nitrogen to minimize contact with atmospheric moisture.

All reaction solutions were filtered through a nylon 0.4 micron Millipore filter immediately before use. - Filtered. All solution handling was done in a dry, inert atmosphere of nitrogen. .

Particle size distribution values were measured using a Reeve Northrop Small Particle Analyzer (SPA). did. This measuring device uses laser light scattering to measure particle size distribution in the 0.1-35 micron range. Set. Scanning electron microscopy (SEM) is used to check particle size values by measuring SPA. It was used to investigate the morphology of powder particles. Make sure that the powder sampling method is appropriate. SEM and SPA granularity data are It always matched.

0 of titanium tetraethoxide in absolute ethanol according to a previously reported method. ．． A 2 molar (M) dilute solution is added to a solution of water in ethanol (0.83M) and this In the experiment, a settling time of about 10 seconds was given to redisperse the particles, and the particle size was measured using SPA. 1 ．． The average particle size with SPA of 3 microns is based on previous patents for this material. It was several times larger than the predicted value. According to the SEM photo of this powder, the surface of the particles is Most of the particles have a diameter of 0.3 microns. hard necked aggregates It was Furthermore, the surface magnified 30,000 times has very few microstructures and is quite smooth. It was. Although the particle size is incorrect, the appearance of the particle surface is consistent with the description of the powder seen in reports for this material. It matches well with the description.

This observation is important. This is because the fine particles on the surface of powder made using various additives This is because the fine structure is significantly different from that obtained in conventional patents.

The observed precipitation times for comparable reagent concentrations were very close to literature values. in general , the precipitation time increases as water reduces the alkoxide concentration, but These differences result in differences in powder particle morphology and particle size. according to the previous method All obtained materials were measured by SPA and independently confirmed by SEM. It is a non-uniform powder agglomerate with an average particle size of 1 micron or more.

A number of different reagent concentrations, reaction temperatures and experimental media were considered.

The grain size and microstructure of titania produced by these methods may vary due to changes in the production medium. There is almost no impact. This medium change occurs during the reaction of titanium ethoxide. Use the received product, the first distilled product, and the second distilled product. Or use 200 proof anhydrous ethanol.

The water used for the reaction was deionized water (18 megohm) and distilled water.

In addition to these precautions, the process of washing, isolating, and redispersing the powder after precipitation is also sufficient. I paid attention. The precipitation reaction can be carried out standing still, but it can also be carried out slowly or with vigorous stirring. The speed of centrifugation can be varied and sonication and sonication can be applied to redisperse the powder. Used as if it were a power or a solvent. More than 40 studies using methods from previous publications The experimental results show that none of the particles obtained reproduce the claimed results. Ta.

stop comparison ■dragon This comparative example shows how triethylamine was measured without using IPC (according to a previously reported experimental method). This is to see the effect. Contains 2 mol% triethylamine (based on titanium) Prepare a 0.2M solution of the alkoxide in ethanol as described in Example I. Mixed with a 0.83M solution in water. With this combination, the precipitation time of solid titania The time increases from 10 seconds to 35 seconds, and the highly aggregated sol and precipitated powder become flat. The average particle size was 10.4 microns. Reconstitute the isolated particle sample in water at pH 10. Upon dispersion, the average SPA particle size of this particle was reduced to 1.1 microns, as in Example ■. The value was very close to the 1.06 micron obtained in the unmodified synthesis as shown in .

In the laser light scattering and SEM characterization results of experiments using triethylamine, , the newly precipitated powder is highly agglomerated and even when redispersed in basic water, it remains 0.9 ml. No particles with an average particle size smaller than Kron were obtained. Distilling amines from barium oxide Powders made using distilled amines are obtained using materials that are not distilled. It showed the same particle size distribution.

Emperor's soil To see the effect of primary amine additives, freshly distilled titanium tetra Ethoxide (Ti(OEt)4) 4sL, secondary butylamine 10μL Mix 100 mL of dry ethanol and 100 mL of dry ethanol in an inert atmosphere of dry nitrogen. Prepare lucoxide solution (A). For the hydrolysis solution (B), add 3 mL of distilled water to anhydrous alcohol. Next, both solutions were prepared by adding 100 L of coal to 0.4 micron micrometers in nitrogen. Remove particulate matter from the solution by separately heating it with Lipore and a nylon filter (and adding water. For decomposition, take equal volumes of both solutions, mix vigorously for a few seconds, then mix well. Let the solution stand for 30 minutes. The liquid, which was initially clear, became cloudy 13 seconds after mixing. child The milky dispersion of titania powder made from - was centrifuged for 20 minutes, and the ethanol was removed. Remove the powder from the compact by tilting it, and place the powder in a small amount of ethanol using ultrasonic waves. Spread. The powder was again isolated by centrifugation, redispersed in 91110 water, and separated by particle size. The fabric was analyzed using a Reeve Northrop Small Particle Analyzer (SPA) with scattered light. Measure. The average particle size of the titania particles was 0.88 microns. powder dispersion By drying a part of the 56M microgram, the shape of the spherical particles of the precipitate was determined. It was separately confirmed that the particle size distribution was uniform.

Specific gravity This comparative example is a pair of comparative experiment with Example ■, and the same raw materials of water and alkoxide solution is used. Using the basic method of Example Solution of 4 sL of freshly collected Ti(GEL)* in 100 mL of pure alcohol Dissolve 1.5*L of distilled water in 100mL of ethanol and treat in the same manner. Added in an atmosphere of dry nitrogen. Stir the resulting solution briefly and let it stand for 20 minutes. did. The initially clear reaction solution began to become cloudy 28 seconds after mixing.

The state of the condensate was observed after it was left standing for 30 minutes. Large clumps of powder particles in the sol This is clear evidence that agglomeration has occurred. by laser light scattering method The average particle size of the precipitate measured was 9.56 microns, which is consistent with visual observation of the lumps. I did it. To reduce the average particle size of the precipitate, the centrifuged compacts were immersed in ethanol. Alternatively, redispersion in ptno water using powerful ultrasound was not very successful. Re The average particle size after dispersion has decreased - but the diameter is still less than 1 micron. There wasn't. According to the results of the SEM examination, the powder particles are mostly hard constrictions with a diameter of 0.3 mm. It was an agglomerate of titania particles with a chron diameter. Average particle size measured by SPA: 1.3 mm From Kron, based on the SEM photo, the "average titania particle" in this sample is , estimated to consist of aggregates of three or more 0.3 micron primary particles of titania. It was.

1 ship ■work This example was carried out to demonstrate the effect of adding the amine of the present invention against comparative example ■. . Comparative example ■An ethanol solution of titanium ethoxide prepared according to 18 microliters of fresh secondary butylamine was added. This solution is 0.4 Filter with a 5 micron Millipore filter, then add 1.5+L of distilled water to 100 aL engineering.

Added to solution in ethanol. This reaction was carried out unmodified as described in the comparative example. ied) The reaction was carried out in parallel, but the solution started to become cloudy 30 seconds after mixing. Contrary to what was mentioned above, the appearance of the There wasn't. Measurement of the average particle size of the dispersion by light scattering method and independently performed SE It turned out to be M's side cane.

Implementation IL This example shows the effect of increasing the amine concentration of the present invention.

Using the method described in Example ■, distilled Ti (OEt) a4taL was converted into pure a Dissolve in 100 mL of cole and add 57 microliters of secondary butyl amine. Make solution A. After filtering with a Millipore filter, add 1.5 sL of solution A to water. Mix with B solution dissolved in 100 sL of pure alcohol. The finished solution takes 55 seconds It becomes cloudy. The average particle size of the precipitated titania particles was 0.47 microns, with particle size and shape The condition is very even. Comparing Example I and ■, it can be seen that the secondary When butylamine was increased, the titania particle size changed from 0.88 microns in Example I to Example I. (2) and further decreases to 0.75 micron as shown in Table 1 of this example.

I 10 microliters 0.88 micron I [1B micro Little 0.75 micron 1 [[57 microliter 0. 47 micron specific gravity u According to Example ■, 8 L of titanium tetraethoxide (ri(oEt) 4 ) in 200 sL of pure alcohol, warmed, and then 0.27 g of Mix hydroxypropyl cellulose (RPC) and stir vigorously to make solution A. and then add it to solution B consisting of 3+wL water and 200+*L pure alcohol. I can do it. Cloudiness appeared after 24 seconds. After 30 minutes, the solution is centrifuged. Once the powder compact is made, wash it as before. This spherical titania The average particle size of the precipitate was 0.21 microns.

1 旌U Same as Comparative Example ■, except that solution A was 106 microliters of triethylamine this time Mix solutions A and B and use the resulting powder compact as before. Similar treatment yields titania with an average particle size of 0.59 microns and high sphericity. . Comparing the above two examples, it can be seen that the addition of triethylamine to RPC is different from that of the present invention. In agreement, the average particle size of the titania powder is 0.21 while maintaining the spherical shape of the particles. It increased from micron to 0.59 micron.

Uraseigoy To determine the effect of various amines on the hydrolysis chemistry of titanium ethoxide. For this purpose, a series of reactions were carried out according to the description in Example (2). As a typical reaction is 2 aaL of Ti(OEt)a with 3 mol% (relative to titanium) of a specific amine. Dissolve in 50 mL of ethanol containing Apply this solution to a micron-sized Millipore The filter was filtered in a nitrogen atmosphere and then washed with 0.75 in 50 mL ethanol. The mixture was thoroughly mixed and then allowed to stand for 30 minutes. The time when turbidity occurs depends on the type of amine. However, it was in the range of 27 to 45 seconds. A small portion of the powder was taken out and subjected to light scattering method and S. Characteristics were investigated by EM. Powder particles are very uniform spherical particles with a particle size distribution of It was small. The results are summarized in Table 2.

Isopropyl 25 microliters 45 seconds 0.50 diethyl 3 1 microliter 43 seconds 0.50 propyl 24 micro Little 30 seconds 0.87 Butyl 29 Microliter 32 seconds 0.75 dibutyl 50 microliters 4 0 seconds 0.44 hexyl 39 microliters 27 seconds 0.62 Secondary Butyl 28 microliters 45 seconds 0 ．． 71 Amendment translation submission form (Patent Law Article 184-8) September 3, 1990 Yoshi, Commissioner of the Patent Office 1) Takeshi Moon PCT/US88100649 2. Name of the invention Method for producing monodispersed titania spheres 3. Patent applicant Address: Morris County, New Chassis, USA 07960 , Morris Township.

Columbia Road and Park Avenue (no street address) Name: Allied-Signal Incorporated 4, Agent Address: Shin-Otemachi Building 206, 2-2-1 Otemachi, Chiyoda-ku, Tokyo 5. Date of submission of written amendment Conventional typical manufacturing methods for backed ceramic products with high value do not allow for the production of defective products that do not meet specifications. Costs are estimated to be as much as 25 to 75% of the manufacturing cost of a particular item. ing. These products reflect processes using traditional ceramic powders and manufacturing techniques. The numbers are clearly unacceptable and The current constraint on the highly technical use of It is a direct result of physicochemical properties. Average particle size, particle size distribution, and coagulation of raw material powder The degree of aggregation and dispersion properties combine to improve the green and final firing of the ceramic. It limits the microscopic materiality of the condensed state. Materiality in the microstructure of ceramics These properties are optimized by processing the powder under tightly controlled conditions. Become. Monodisperse metal oxide powder obtained by the sol-gel method has this morphology. It is the best example of this material.

Monodisperse metal oxide powders offer many process advantages over traditional ceramic powders. I can do it. The spherical shape and narrow point of particle size distribution of monodisperse powders make green ceramics allows tight control over the loading of powder particles in the container. There are very few aggregates. , the particle packing is very uniform and the residual pore size in the green ceramic is Slowly coagulates a dispersion of 0 particles, which is often 2 particles in diameter (1μ or less). Then, due to the statistical arrangement of the particles, the residual pore size is often smaller than the diameter of a single particle. You can get something like that. Residual pores and agglomerates of 1 micron (or larger) are removed by firing. If present in the formed ceramic structure, it can cause cracks and defects in the material and damage the overall structure. This is an extremely important advantage since it reduces the performance and strength of the material. Traditional In the processing of ceramic powders, residues due to insufficient powder packing and agglomerates can be It is very difficult to remove porosity and defects. To do this, use ceramic Typical methods include pressurization for densification and addition of sintering aids for particle growth. It is the law. Pressurization during high-temperature processing is extremely costly and is not desirable. . The addition of sintering aids is also undesirable, since it adversely affects the high temperature properties of the material.

For particles of a single dimension, these treatments can achieve density, microstructural symmetry, and sinterability. It is not necessary to accomplish this.

European published patent publication @0186149 discloses that inorganic oxide-containing airgel is Emphasis is placed on the use of supercritical extraction of the solvent used in the production of the oil. child The gel is formed under acidic conditions, and the gel produced by the inventors under basic conditions is It is very different from a small ball.

In the UK patent application GB2170189A, a much larger 1 The production of spheres up to 000 g va is discussed. This large sphere is in an aqueous solution Obtained by forming a dispersion of organometallic oxide precursor droplets.

The droplets are then allowed to react while being protected by a protective colloid.

Journal of the Ceramic Society of America 65 (E 1574.77 (1986)) Methods similar to the present invention are discussed. There, hydroxypropyl cellulose A carbonaceous solution is used to prevent agglomeration of small particles of TiO□.

1st corridor JL abbreviation It is therefore an object of the present invention to produce titania monodisperse spheroidal bodies as molded compacts and provides a reproducible method of manufacturing (as a dispersion in a suitable fluid medium) be.

Another object of the invention is to produce titania spheroids with individual particle sizes in the range of about 0.1-1 μm. In addition, the particle size distribution standard is about 1/2 of the average particle size, i.e. monodisperse or monodisperse. This is defined as the size provided.

The content of the present invention is to convert titanium tetraalkoxide into a liquid consisting of alcohol. to form a solution of the alkoxide and then add an amine-containing particle size control additive. A solution of alcohol and water containing alcohol and water to produce a precipitate of solid monodisperse spherical titania. This is a method for producing monodisperse titania, which consists of the steps of:

It is found in the manufacturing process of monodisperse titania, which consists of a step of producing monodisperse titania.

Another embodiment of the invention is to use basic water or titanium alkoxide based sols. production of monodisperse titania particles by aging a dispersion of said titania in a medium such as Found in the process of increasing internal porosity.

Still other aspects of the invention include adding the dispersion of titania particles to a porous mold and green body compact consisting of recovery of said solid green body compact from the mold of This can be seen in the manufacturing method of impact.

Other objects and embodiments are found in the following more detailed description of the invention.

In the present invention, titanium tetraalkoxide is alco.

The concentration of the solution is preferably in the range of 0.05 to 1.0 M/1.

The water content of the final hydrolysis mixture is between 0.2 and 1.5 M/j! Do not exceed the molar concentration of and that the initial alcohol solution has a pH of 500 ppm, preferably 200 ppm or less. It is important not to have water on top. Furthermore, titanium tetraalkoxide The water content of alcohol is preferably 100 to 300 pps+.

The present invention provides a new particle size for producing single-sized titania by sol-gel chemistry. Concerning control additive systems. Secondary amines and triethylamine/hydroxylamine Lopil cellulose is a desirable additive system for the powder during precipitation/formation. In addition to preventing particle agglomeration, it is also possible to directly A monodisperse spherical powder is produced.

These additives produce highly uniform dispersions of single-sized titania particles that are highly reproducible. It provides a method that can be manufactured with high efficiency, and is very superior to the above-mentioned known methods. Typical examples are 0.001 to 0.1M#! Use in sufficient amount to form a solution containing I can stay.

The most widespread type of am is amines with alkyl groups of 1 to 7 carbon atoms in length. This makes the process of the invention effective. The best results are given by Hydroxypro In the absence of pill cellulose (RPC), mono- or di-substituted amines are the best Get results and give results. Use mixtures of amines as well as individual amines It is also within the scope of the present invention to do so.

The mono- and di-substituted amines of the present invention include, but are not limited to, ethyl alcohol. amine, diethylamine, methylamine, dimethylamine, propylamine, dipropylene Lopylamine, butylamine, dibutylamine, pentylamine, diisothyla hexylamine, diethylamine, heptylamine, diethylamine, Sopropylamine, diisopropylamine, isobutylamine, diisobutylamine amine, 5ec-butylamine, di-5ec-butylamine, tert-butylamine amine, di-tert-butylamine, isopentylamine, tert-butylamine selected from the group of amines, ethylpropylamine, hexylbutylamine, and others. Ru.

The trialkylamines of the present invention include, but are not limited to, triethyl amines. Trimethylamine, Triisopropylamine, Tributylamine, Trimethylamine, Trimethylamine, Triisopropylamine, Tributylamine sobutylamine, tri-5ec-butylamine, tri-tert-butylamine tripentylamine, triisopentylamine, trihexylamine, tripentylamine, tripentylamine, triisopentylamine, trihexylamine, heptylamine, methyldiethylamine, ethylmethylpropylamine, propylamine diethylamine, hexylmethylpentylamine, propyl ethyl to butyl amine amine, pentyldibutylamine, and others.

The standard deviation of the variable distribution is 172 or less of the average particle size.

In a preferred embodiment, the 5ec-butylamine concentration is about 0.001 to 0.1 M#2 and the concentration of triethylamine should be in the range of about 0.0OL to 0. ．． 1M#2 range, and the concentration of hydroxypropyl cellulose is alkoxy It should be between 0.5 and 5% by weight based on the amount of carbon. Or triethyla Amines such as amines are present in the range of about 1 to 6 mole percent based on the titanium metal. be able to.

These amine additives increase the relative sparseness of the powder particles. In addition to controlling the average particle size of the precipitated powder, it is also possible to It is valid. By simply changing the concentration of amine-containing additives, the fine particle size of the powder can be improved. The average particle size of the titania particles increases or decreases while maintaining the distribution. This particle size change is caused by water However, the concentration of both alkoxide reagents (and other reaction media as well) is carried out under constant conditions.

This is a fundamental advance in the manufacture of these materials.

Monodisperse titania particles correspond to a standard deviation of the particle size distribution less than 172 of the average particle size. manufactured with a relatively narrow particle size distribution.

On the other hand, in the conventional method, the particle size significantly exceeds 1μ, the uniformity is poor, and the standard deviation The difference is not less than the average particle size. The present invention has a particle size of 0.1 to 1.0 μm. Uniform spherical particles are produced, in contrast to particles produced in experiments using conventional methods. produces particles with a particle size of 1 μm or more. Sharpness obtained using the method of the invention The spherical shape and narrow particle size range make the ceramic In industry, dense and microstructurally uniform green-body tania particles can be reproduced. According to scanning electron microscopy (SEM), the product of the known method has no lead 1.2μ as measured by the Northrop Small Particle Analyzer (SPA) It is a highly agglomerated mass of particles with an average particle size of This previous method was 0.3-0 ．． reported a particle size of 7μ intestine, but we have not attempted to replicate this method broadly and deeply. However, the resulting particles were 1.2 μm in diameter, hard, intertwined, and inseparable. It was an aggregate of spherical titania particles with a diameter of 0.3 μm.

In this specification and the appended claims, the term "compact" is defined as: A porous type with a dispersion of separated non-redispersed titania and monodispersed titania molded solid titanium obtained or obtained by other molding methods known to those skilled in the art. This includes both (a). Also, the term "green body" refers to unfired presses. Define to mean ramic compact.

Although the following examples are provided for illustrative purposes, they are not intended to be illustrative in nature. It is understood that the present invention is not necessarily limited to this. I want to be

soil comparison±1 In order to distinguish the present invention from conventional patents, products must be made using methods described in the literature. Ta.

Titanium tetraethoxide was purchased from three different manufacturers and vacuum distilled. and carefully handled under inert nitrogen to minimize contact with atmospheric moisture.

All reaction solutions were passed through a nylon 0.4 μm millibore filter immediately before use. I passed away. All solution handling was done under a dry, inert atmosphere of nitrogen.

Particle size distribution values were measured using a Laser Northrop Small Particle Analyzer (SPA). did. This measuring device uses laser light scattering to measure particle size distribution in the 0.1-35μm range. Ru. Scanning electron microscopy (SEM) is used to check particle size values by measuring sp. It was used to examine the morphology of particles. Ensure that the powder sampling method is appropriate. As long as proper care is taken, SEM and SPA granularity data are highly It matched.

0 of titanium tetraethoxide in absolute ethanol according to a previously reported method. ．． A 2 molar (M/1') dilute solution of water in ethanol was given. Got it after 30 minutes Wash the light powder with ethanol, redisperse it in deionized water at pH 1o, and reduce the particle size with SPA. It was measured. The average particle size by SPA of 1.3 μ- It was several times larger than the value claimed by the patent. According to the S8M photograph of this powder, the particles are The surface is curved or spherical, and most of the particles are 0.3uya. hard necked aggregation of particles of about tes).

Furthermore, the surface magnified 30,000 times has very few microstructures and is quite smooth. It was. Although the particle size is incorrect, the appearance of the particle surface is consistent with the description of the powder seen in reports for this material. It matches well with the description.

This observation is important. This is because the fine particles on the surface of powder made using various additives This is because the fine structure is significantly different from that obtained in conventional patents.

The observed precipitation times for comparable reagent concentrations were very close to literature values. in general , reducing the concentration of water or alkoxide increases the precipitation time, but These differences result in differences in powder particle morphology and particle size. according to the previous method All obtained materials were measured by SPA and independently confirmed by SEM. It is a non-uniform powder agglomerate with an average particle size of 1 micron or more.

A number of different reagent concentrations, reaction temperatures and experimental media were considered.

The grain size and microstructure of titania produced by these methods may vary due to changes in the production medium. There is almost no impact. This medium change occurs during the reaction of titanium ethoxide. Use the received product, the first distilled product, and the second distilled product. Or use 200 proof anhydrous ethanol.

The water used for the reaction was deionized water (18 megohm) and distilled water.

In addition to these precautions, the process of washing, isolating, and redispersing the powder after precipitation should also be carried out with sufficient care. I paid attention. The precipitation reaction can be carried out statically or with slow or vigorous stirring. The centrifugation speed was varied and sonication was applied to redisperse the powder. -Used as if it were a power or solvent. More than 40 using methods from previous publications Experimental results show that none of the particles obtained reproduce the claimed results. It was.

Specific gravity This comparative example shows the effect of triethylamine when RPC is not used in a previously reported experimental method. It is for seeing the fruit. Contains 2 mol% triethylamine (based on titanium) A 0.21'l/f solution of the alkoxide was prepared and ethanol was added as described in Example I. The mixture was mixed with a 0.83 M/l solution of water in a bottle. With this combination, solid titania The precipitation time increased from 10 seconds to 35 seconds, resulting in precipitation from a highly aggregated sol. The powder had an average particle size of 10.4 microns. Isolated particle sample in water at pH 0 When redispersed, the average SPA particle size of this particle decreased to 1.1 u+m, and Example I The value in sharp contrast to that obtained with the unmodified synthesis (1,06 μm) as in It became.

In the laser light scattering and sEh characterization results of experiments using triethylamine, , the newly precipitated powder is highly agglomerated and even when redispersed in basic water, the 0.9μ No particles with an average particle size smaller than haze were obtained. Distilling amines from barium oxide Even if purified, powders made using distilled amines are obtained using materials that are not distilled. It showed the same particle size distribution.

1 piece on a plate To see the effect of primary amine additives, freshly distilled titanium tetra Ethoxide (Ti (OEt) a) 4+L, secondary butylamine 10 mic Mix Lolitol and 100 mL of dry ethanol in an inert atmosphere of dry nitrogen. An alkoxide solution (A) is prepared. Hydrolysis solution (B) is distilled water 3+aL Both solutions prepared by adding 100a+L of absolute alcohol to 0.4% in nitrogen ■ Separately filter with millibore and nylon filters to remove particulates from the solution. .

For hydrolysis, take equal volumes of both solutions, mix vigorously for a few seconds, then mix well. Let the solution stand for 30 minutes. The initially clear liquid becomes cloudy 13 seconds after mixing. . The milky dispersion of titania powder made in this way was centrifuged for 20 minutes, and the ethanol Tilt and remove the powder from the powder compact, and place the powder in a small amount of ethanol under ultrasonic waves. dispersed by waves. The powder was again isolated by centrifugation, redispersed in pH 10 water, and the particle size Open the Reeve Northrop Small Particle Analyzer (SPA) to measure the distribution using scattered light. Measure. The average particle size of the titania particles was 0.88 am. powder dispersion By drying a part of the 58M microgram, the shape of the spherical particles of the precipitate was determined. It was separately confirmed that the particle size distribution was uniform.

Specific gravity group This comparative example is a pair of comparative experiment with Example ■, and the same raw materials of water and alkoxide solution is used. Using the basic method of Example I, millibore filtered evaporation Dissolving 4 L of freshly collected Ti(OE・t)a in 100 L of pure alcohol. The solution was dissolved in 1.5L of distilled water in 100+aL of ethanol and treated in the same manner. was added in an atmosphere of dry nitrogen. The resulting solution was stirred briefly for 20 min. I left it still. The initially clear reaction solution began to become cloudy 28 seconds after mixing.

The state of the condensate was observed after it was left standing for 30 minutes. Large clumps of powder particles in the sol This is clear evidence that agglomeration has occurred. by laser light scattering method The average particle size of the precipitate measured was 9.56 μm, which is consistent with the visual observation of the mass. Ta. To reduce the average particle size of the precipitate, the centrifuged compacts were soaked in ethanol or was redispersed in pH 10 water using powerful ultrasound without much success. redispersion Although the average particle size has decreased, the diameter has never been less than 1 μm. . According to the results of 5EM examination, powder particles are mostly hard constricted chips with a diameter of 0.3μ. It was an aggregate of Tania particles. From steel with an average grain size of 1.3μ measured by SPA, S8 Based on the M photo, the "average titania particles" in this sample are titania.

It was estimated to consist of aggregates of three or more primary particles of 0.3 μm.

Royal family ■Engineer This example was carried out to demonstrate the effect of adding the amine of the present invention against comparative example ■. . Comparative example ■An ethanol solution of titanium ethoxide prepared according to 18 microliters of fresh secondary butylamine was added. This solution is 0.4 Filter with a 5I11 millibore filter, then add 1 liter of distilled water, 1' of 5 sL ( ) was added to the solution in OmL ethanol. This reaction was carried out unmodified (unmodified) as described in the comparative example. *-odified) reaction was carried out in parallel, but the solution started to become cloudy 30 seconds after mixing. The appearance of the collected zero dispersion, contrary to the above, is very symmetrical with no visible large precipitates. There was nothing to be done. Measurement of the average particle size of the dispersion by light scattering method and independently In the SEM measurement of the line, it was 0.75 μm. Furthermore, particle morphology by SEM was found to be spherical.

Ura-sebandan This example shows the effect of increasing the amine concentration of the present invention.

Example ■ Using the method described, 44 mL of distilled Ti (OEt) was mixed with pure alcohol. Dissolve in 100 mL and add 57 microliters of secondary butyl amine to make solution A. make. After filtering with a Millipore filter, add 1 part of solution A and 1 part of 5n+L water. Mix with solution B dissolved in 00 mL of pure alcohol. The resulting solution becomes cloudy in 55 seconds. Ru. The average particle size of the precipitated titania particles was 0.47 μm, and the particle size and morphology were non-uniform. Always proportionate. Comparing Example I and ■, it can be seen that the secondary butyl in solution A When the amine was increased, the titania particle size increased from 0.88 μ scales in Example I to 0.7 μ scales in Example II. 5 μm, and further decreases as shown in Table 1 of this example.

1 10 microliters 0.88 μm II 1B micro liter 0.75μ 1[[57 micro liter] 0.47μ - 1 koku 1■ 8 mL of titanium tetraethoxide (Ti(OEt)4) according to Example ■ A solution in 200 mL of pure alcohol was prepared, filtered, and then 0.27 g of hydroxide Combine xypropyl cellulose (HPC) and stir vigorously to make solution A. , then add this to solution B consisting of 3a+L water and 200++L pure alcohol. Ru. Cloudiness appeared after 24 seconds. After 30 minutes, the solution is centrifuged to form a powder. Now that you have a compact, clean it as before. This spherical titania precipitate The average particle size of the precipitate was 0.21 μm.

Officer Jitsugai■ Same as Comparative Example ■, except that solution A was 106 microliters of triethylamine this time Mix solutions A and B and use the resulting powder compact as before. When treated in the same manner, titania with an average particle size of 0.59 μm and high sphericity is obtained. Below Comparing the above two examples, the addition of triethylamine to the RPC is consistent with the present invention. As a result, the average particle size of the titania powder was reduced to 0.21 μm while maintaining the spherical shape of the particles. It increased from 0.59μ- to 0.59μ-.

Tips M To determine the effect of various amines on the hydrolysis chemistry of titanium ethoxide. For this purpose, a series of reactions were carried out according to the description in Example (2). As a typical reaction 2 mL of Ti(OEt)a was added to 3 mol% (relative to titanium) of a specific amine. Dissolve in 50+aL of ethanol containing This solution is A filter in a nitrogen atmosphere and then in 50 + + L ethanol. Add to 75 mL of water solution. Always stir the initially clear reaction solution at high speed to mix well. Then, it was left to stand for 30 minutes. The time when turbidity occurs depends on the type of amine. was in the range of 27 to 45 seconds. A small portion of the powder is taken out for light scattering and SEM. Therefore, we investigated its characteristics. The powder particles are very uniform spherical particles with a narrow particle size distribution. It was. The results are summarized in Table 2.

” table Isopropyl 25 microliters 45 seconds 0.50 diethyl 31 microliters 43 seconds 0.50 propyl 24 mi Chloritol 30 seconds 0.87 butyl 29 microliters 3 2 seconds 0.75 dibutyl 50 microliters 40 seconds 0.44 hexyl 39 microliters 27 seconds 0.6 2 Secondary Butyl 28 microliters 45 seconds 0.71 Claims Surroundings 1. a) Dissolve titanium tetraalkoxide in a liquid containing alcohol. A process for preparing a solution of the alkoxide having 1 to 4 carbon atoms in the alkyl group. and b) monoalcohol in combination with hydroxypropyl cellulose. From kylamines, dialkylamines, trialkylamines and mixtures thereof and the amines have 1 to 7 carbon atoms in the alkyl group. A solution of alcohol and water containing an amine-containing particle size control additive selected from A step in which a precipitate of solid monodisperse titania spherules is produced in addition to the solution A method for producing monodisperse titania spheres comprising:

λ The method according to claim 1, wherein the alcohol has the chemical formula ROH (R is a carbon atom) (representing a lower alkyl group having 1 to 4 molecules).

3. The method according to claim 1 or 2, wherein the titanium tetraalkoxy from 0.05M/1 to 1.0M#! method present in a range of concentrations.

4. The method according to claim 1.2 or 3, wherein the alcohol is ethanol. , methanol, 1-butanol, 1-propertool, 2-propertool, 2-butanol a method selected from the group of tanol and 2-methyl-2-propanol .

5. The method according to any one of claims 1 to 4, wherein the amine-containing particle size control addition If the agent is isopropylamine, diethylamine, propylamine, butylamine, Consisting of secondary butylamine, dibutylamine, hexylamine and mixtures thereof The method of being an amine selected from the group.

6. The method according to any one of claims 1 to 5, wherein the additive is present in the solution at a concentration of 0.0 01M#! ~0.1M#! How to exist within the range of.

7. The method according to any one of claims 1 to 6, wherein the additive is triethylamine. A method in which a mixture containing ester and hydroxypropyl cellulose is used.

8. The method according to claim 7, wherein triethylamine is based on titanium. Hydroxypropylcellulose is added to the solution in an amount of 1 to 6 mol%, and titanium Dissolved in an amount equivalent to 0.5 to 5% by weight based on nium tetraalkoxide. How to add it to a liquid.

international search report 111-＾＠＠＃＋１＃-とGolυ588100649 International Investigation Report L 128800649

Claims (8)

[Claims] 1. a) Dissolving titanium tetraalkoxide in a liquid consisting of alcohol A solution of the alkoxide is made, and then b) an amine-containing particle size control addition is made to the resulting solution. monodisperse spheres consisting of solid monodisperse spherical titania precipitates upon addition of solid monodisperse spherical titania precipitates. Production method of titania. 2. 2. The method of claim 1, wherein the alcohol has the chemical formula ROH, where R is a carbon atom. (representing a lower alkyl group having 1 to 4 molecules). 3. 3. The method according to claim 1 or 2, wherein the titanium tetraalkoxide is present in the solution at a concentration ranging from 0.05M to 1.0M. Method. 4. 4. The method according to claim 1, 2 or 3, wherein the alcohol is ethanol, Methanol, 1-butanol, 1-brobanol, 2-brobanol, 2-butanol selected from the group of alcohol and 2-methyl-2-brobanol. How to characterize it. 5. 5. The method according to claim 1, wherein the amine-containing particle size control additive Additives include isopropylamine, diethylamine, propylamine, butylamine, Comprising secondary butylamine, dibutylamine, hexylamine and mixtures thereof. The method is characterized in that the amine is selected from the group consisting of: 6. 6. A method according to any one of claims 1 to 5, wherein the additive is present in the solution at a concentration of 0.0 01M to 0.1M. 7. 7. The method according to claim 1, wherein the additive is triethylamine. and hydroxypropyl cellulose. 8. 8. The method of claim 7, wherein triethylamine is added to to the solution in an amount of 6 mol% and hydroxypropyl cellulose. In an amount equivalent to 0.5 to 5% by weight based on tanium tetraalkoxide. A method characterized in that it is added to a solution.