KR100491344B1 - Titanium oxide particles and composition containing the same - Google Patents

Abstract

Titanium oxide fine particles having a BET specific surface area of 3m ² / g~200m ² / g is 4 the titanium chloride in the vapor phase to a high temperature to prepare a titanium oxide by oxidation with an oxidizing gas, the oxidizing gas and the gas containing titanium tetrachloride each It is obtained by preheating to 500 degreeC or more, supplying it to a reaction tube, and making it react. This fine particulate titanium oxide is fine particles with little aggregation and is excellent in dispersibility.

Description

Titanium oxide fine particle and the composition containing it {TITANIUM OXIDE PARTICLES AND COMPOSITION CONTAINING THE SAME}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to particulate, particularly particulate titanium oxide obtained by a gas phase method, a method for producing the same, and a composition containing the same. Titanium and its manufacturing method.

Industrial applications of particulate titanium oxide, in particular ultrafine titanium oxide, are very wide, and their applications, including ultraviolet shielding materials, additives to silicone rubber, and photocatalysts, are widely used. JIS) is called "titanium dioxide", but "titanium oxide" is also used as a general name. Therefore, hereinafter, this brief term will be used in the description of the present invention.

For example, in the field of cosmetics, clothing materials, etc., the use for shielding ultraviolet rays is considered more important in recent years. As a shielding material, ultrafine titanium oxide has high safety and is used a lot. Shielding requires two functions, ultraviolet absorption and scattering, but the ultrafine titanium oxide has both functions.

Titanium oxide has the property of absorbing ultraviolet rays having a wavelength of about 400 nm or less to excite electrons. The electrons and holes generated in the titanium oxide fine particles absorbing ultraviolet rays, when reaching the particle surface, are combined with oxygen or water to generate various radical species. Since radical species have an effect of decomposing organic matter, when titanium oxide is used in cosmetics or the like, surface treatment is generally performed on the ultrafine particles of titanium oxide. Further, fine titanium oxide is used to utilize the photocatalytic reaction by photoexcitation of titanium oxide. When titanium oxide is used for the purpose of scattering ultraviolet rays, ultrafine titanium oxide having a primary particle diameter of about 80 nm is used. In general, the primary particle diameter of the ultrafine particles is not clear, but is usually referred to for fine particles of about 0.1 μm or less.

Titanium oxide is generally a liquid phase method of hydrolysis in a hydrophilic solvent using titanium tetrachloride or titanium sulfate as a raw material, or a volatile raw material such as titanium tetrachloride is vaporized, followed by an oxidizing gas such as oxygen or water vapor, and a gaseous state. It is prepared by using a gas phase method to react under high temperature. For example, Japanese Patent Application Laid-Open No. Hei 1-45307 discloses a method for producing spherical metal oxide ultrafine particles by setting a flow rate of either a volatile metal compound or water vapor to 5 m / sec or more.

Generally, the titanium dioxide powder produced by the liquid phase method has the drawback that aggregation is severe. Therefore, when titanium oxide is used in cosmetics or the like, it is necessary to disintegrate or pulverize titanium oxide strongly, causing problems such as mixing of abrasions caused by processing such as grinding, uneven particle size distribution, and deterioration of touch.

Also in the case of titanium dioxide produced by the gas phase method, in the conventional gas phase method, ultrafine titanium oxide is obtained, but only grain grown titanium oxide particles are obtained. In order to obtain particulate titanium oxide, it is necessary to strongly disintegrate or pulverize the titanium oxide. And had the same problems as in the liquid phase method.

Summary of the Invention

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a titanium oxide having excellent dispersibility, as a particulate form having a very small agglomeration, especially an ultrafine grain form.

An object other than the present invention is to provide a method for producing such particulate titanium oxide.

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching the said problem, the present inventors succeeded in obtaining the microparticles | fine-particles of titanium oxide which were very excellent in dispersibility by preheating raw material gas and oxidizing gas in the vapor phase method, respectively.

That is, in the gas phase method for producing titanium oxide by oxidizing titanium tetrachloride with an oxidizing gas at high temperature, the method for producing titanium oxide according to the present invention comprises reaction of preheating the gas containing titanium tetrachloride and the oxidizing gas to 500 ° C. or higher, respectively. was reacted by supplying the tube, BET specific surface area of 3m ² / g~200m ² / g of the fine particle titanium oxide, in particular BET specific surface area of ^{5m 2 / g~200m 2 / g,} 2 / g is further a BET specific surface area of 10m It is characterized by producing particulate titanium oxide which is ˜200 m ² / g.

At this time, the gas and the oxidizing gas containing the preheated titanium tetrachloride can be supplied to the reaction tube at a flow rate of 10 m / sec or more, respectively.

In addition, a gas containing preheated titanium tetrachloride and an oxidizing gas are supplied to the reaction tube, and the temperature in the reaction tube is 3 seconds or less, preferably 1 second or less, and more preferably 0.5 second at a high temperature condition exceeding 600 ° C. It can be made to react by holding for the following time.

The method for producing particulate titanium oxide of the present invention is a gas phase method for producing titanium oxide by high temperature oxidation of titanium tetrachloride with an oxidizing gas, wherein the gas containing titanium tetrachloride and the oxidizing gas are respectively preheated to 500 ° C. or higher. High temperature conditions in which the preheated titanium tetrachloride gas and the oxidizing gas are respectively supplied to the reaction tube at a flow rate of 10 m / sec or more, the average flow rate in the reaction tube is 5 m / sec or more, and the temperature in the reaction tube exceeds 600 ° C. At 3 seconds or less, preferably 1 second or less, more preferably 0.5 seconds or less, and the reaction is characterized in that the reaction.

In each of the above production methods, after preheating the gas containing titanium tetrachloride and the oxidizing gas to 500 ° C. or higher, respectively, the preheated titanium tetrachloride gas and the oxidizing gas are supplied into the reaction tube to cause turbulence in the reaction tube. It is preferable.

Further, the gas containing titanium tetrachloride and the oxidizing gas are supplied into the reaction tube by a coaxial parallel flow nozzle, and the inner diameter of the coaxial parallel flow nozzle inner tube may be 50 mm or less.

In addition, the gas containing titanium tetrachloride may contain 10% to 100% of titanium tetrachloride.

The temperature for preheating the gas containing titanium tetrachloride and the oxidizing gas may be 800 ° C. or higher.

Microparticulate titanium oxide of the present invention, a BET specific surface area of 3m ² / g~200m ² / g of particles and, in particular, a BET specific surface area of 5m ² / g~200m ² / g, also a BET specific surface area of 10m ² / g Ultra-fine particles of ˜200 m ² / g, and characterized in that 90% cumulative weight particle size distribution diameter D90 is 2.2 μm or less.

Microparticulate titanium oxide of the present invention, and a BET specific surface area of 3m ² / g~200m ² / g, in particular 5m ² / g~200m ² / g, also 10m ² / g~200m ² / g, also under rosin The distribution constant n by the lambda formula is characterized by being 1.7 or more.

R = 100exp (-bD ⁿ )

(Wherein D represents a particle diameter and b is an integer.)

The particulate titanium oxide of the present invention is produced using any one of the above production methods.

Further, the particulate titanium oxide composition of the present invention is characterized by containing at least one kind of the titanium oxide.

The above and other objects, effects, features and advantages of the present invention will be described below with reference to the accompanying drawings.

The ultrafine titanium oxide of the present invention is produced by high temperature oxidation using oxygen or water vapor or a mixed gas (hereinafter referred to as "oxidizing gas") in a gas phase method using gas containing titanium tetrachloride as a raw material. However, the gas containing titanium tetrachloride and the oxidizing gas need to be preheated to 500 ° C. or higher before introduction into the reaction tube.

In the present invention, it is preferable to introduce each of the gas containing titanium tetrachloride and the oxidizing gas into the reaction tube at a flow rate of 10 m / sec or more, preferably 30 m / sec or more, and under high humidity conditions in the reaction tube. It is preferable to react these gases so that the time for the gas to stay and react (hereinafter also referred to as "high temperature residence time") is within 3 seconds, preferably within 1 second, more preferably within 0.5 seconds. According to this production, the dispersion is extremely high, the BET specific surface area of 3m ² / g~200m ² / g of titanium oxide on the particles, especially having a BET specific surface area of 5m ² / g~200m ² / g, further a BET specific surface area 10m ² / g~200m the titanium oxide on the ultrafine particles ² / g is obtained. Titanium oxide produced so far by the vapor phase method had a BET specific surface area of less than 10 m ² / g.

In this invention, the particle size distribution measured by the laser diffraction type particle size distribution measuring method is employ | adopted as an index of dispersibility. The particle size distribution measurement procedure will be described as follows.

Ultrasonic irradiation (46KHz, 65W) was performed for 3 minutes to the slurry which added 50 micrometers of pure waters, and 100 microliters of 10% of 10% hexamethyl phosphate aqueous solution to 0.05 g of titanium oxides. This slurry is hanged on a laser diffraction particle size distribution measuring apparatus (SALD-2000J manufactured by Shimadzu Corporation) to measure the particle size distribution. When the value of the 90% cumulative weight particle size distribution diameter D90 in the particle size distribution thus measured is small, it is judged that the dispersibility is good in the hydrophilic solvent.

The fine particle titanium oxide of the present invention is excellent in uniformity of particle size. In the present invention, the Rosin-Rammler equation is used for the uniformity of the particle size, and the distribution constant n is defined. Hereinafter, the rosin-lamellar type will be briefly described. Details thereof are described in pages 596 to 598 of the Ceramic Engineering Handbook (first edition of the Japan Ceramic Association, Inc.).

The rosin-lamer type is represented by the following formula (1).

R = 100exp (-bD ⁿ ) (1)

In the formula, D represents a particle size, b is an integer, R is a percentage of the total number of particles larger than D (particle size), n is a distribution integer.

In this case, if b = 1 / De ⁿ , the formula (1)

R = 100exp {-(D / De) ⁿ } (2)

Can be changed to However, De is a particle size characteristic number, n is an integer called a distribution constant. The constant b in the formula (1) is the particle size characteristic De, i.e., from the particle diameter and distribution constant n for the plus particle (ober particle diameter) 36.8% (R = 1 / e = 0.368), the formula (b = 1 / De ⁿ ) Is an integer derived by.

The following formula (3) is obtained from formula (1) or formula (2).

log {log (100 / R)} = nlogD + C (3)

However, in formula, C represents an integer. From the above formula (3), when these relationships are plotted on a rosin-lambler (RR) diagram with a scale of 1ogD on the x-axis and 1og {log (100 / R)} on the y-axis, the line becomes almost straight. The gradient n of the straight line represents the degree of uniformity of the particle size, and it is judged that the larger the value of n, the better the uniformity of the particle size.

It is preferable that 90% cumulative weight particle size distribution diameter D90 of the particulate-form titanium oxide of this invention is 2.2 micrometers or less, and it is preferable that distribution constant n by rosin-lambler type is 1.7 or more.

The particulate titanium oxide of the present invention is included as a particle component using pigments or photocatalytic effects of various compositions, and specifically, it can be used for additives of various products such as cosmetics, medical care, ultraviolet shielding materials or silicone rubber.

Next, the manufacturing method of titanium oxide is demonstrated.

A general method for producing titanium oxide by the gas phase method is known, and when titanium tetrachloride is oxidized using an oxidizing gas such as oxygen or water vapor under reaction conditions at about 1,000 ° C., fine particulate titanium oxide is obtained.

There are two types of growth mechanisms of particles in the gas phase method, one of which is CVD (chemical vapor growth), and the other is growth by collision (merging) or sintering of particles. In order to obtain the ultrafine titanium oxide for the purpose of the present invention, all of these growth times must be shortened. That is, in the growth of electrons, the growth can be suppressed by increasing the preheating temperature and increasing the chemical reactivity (reaction rate). In the latter growth, growth by sintering or the like can be suppressed by cooling, diluting or the like immediately after completion of CVD and minimizing the high temperature residence time as much as possible.

In the present invention, in the gas phase method for producing titanium oxide by oxidizing a gas containing titanium tetrachloride to an oxidizing gas at high temperature, by preheating the gas containing titanium tetrachloride and the oxidizing gas to 500 ° C. or higher, respectively, has been found that it is possible to inhibit the growth of CVD and, BET specific surface area of 3m ² / g~200m ² / g can be obtained in the titanium oxide fine particles.

In addition, the titanium oxide fine particles of the present invention are composed of amorphous or non-spherical particles, and are different from spherical particles as disclosed in Japanese Patent Application Laid-Open No. Hei 1-45307 (transmission electron microscope of titanium oxide particles obtained in Example 2). See photo).

The gas containing titanium tetrachloride as a raw material preferably has a concentration of titanium tetrachloride in the gas of 10% by volume to 100% by volume, more preferably 20% by volume to 100% by volume. When a gas having a titanium tetrachloride concentration of 10% by volume or more is used as a raw material, the generation of uniform nuclei or reactivity increases, making it difficult to form grown particles by CVD domination, thereby obtaining particles having a narrow particle size distribution.

It is also to be chosen that the gas which dilutes titanium tetrachloride in the gas containing titanium tetrachloride does not react with and is not oxidized with titanium tetrachloride. Specifically, nitrogen, argon, etc. are mentioned as a preferable dilution gas.

The preheating temperature of the gas containing titanium tetrachloride and the oxidizing gas may be the same or different, but each must be at least 500 ° C, preferably at least 800 ° C. However, the smaller the preheating temperature difference of each gas is, the better, but the preheating temperature difference depending on the target particle size may be selected within a range not exceeding 300 ° C. When the preheating temperature is lower than 500 ° C., since the generation of uniform nuclei is less and the reactivity is low, the particle size distribution of the particulate titanium oxide obtained is widened. On the other hand, the preheating temperature is sufficient if the reaction temperature below.

It is preferable that the flow velocity at the time of introducing the gas containing titanium tetrachloride and an oxidizing gas into a reaction tube is 10 m / sec or more. This is because increasing the flow rate promotes mixing of the gases. When the temperature of gas introduction into the reaction tube is 500 ° C or higher, the reaction is completed at the same time as mixing, so that the generation of uniform nuclei is enhanced and the zone in which grown particles are formed by CVD domination can be shortened.

In the present invention, the source gas is preferably introduced into the reaction tube so that the gas introduced into the reaction tube is sufficiently mixed. If the gases are sufficiently mixed, there is no particular limitation as to the fluid state of the gas in the reaction tube, but it is preferably a fluid state in which turbulence occurs, for example. Swirl streams may also be present. If there is a difference in the preheating temperature described above, turbulence or vortex flow of the gas introduced into the reaction tube may occur.

Moreover, although the nozzle which provides coaxial parallel flow, cross flow, cross flow, etc. is employ | adopted as an introduction nozzle which introduces source gas into a reaction tube, it is not limited to these. In general, coaxial parallel flow nozzles have a somewhat lower degree of mixing than nozzles for providing cross flow and cross flow, but are preferably used in design because they have a simple structure.

For example, in the case of a coaxial parallel flow nozzle, a gas containing titanium tetrachloride is introduced into the inner tube. However, the inner tube diameter is preferably 50 mm or less from the viewpoint of gas mixing.

In the present invention, the flow rate of the gas introduced into the reaction tube in the reaction tube is preferably large in order to completely mix the gas, and in particular, the average flow rate is preferably 5 m / sec or more. When the flow rate of the gas in the reaction tube is 5 m / sec or more, the mixing in the reaction tube can be sufficiently performed, the generation of grown particles due to CVD domination is small, and the particles having a wide particle size distribution are not produced.

This reaction in the reaction tube is an exothermic reaction, and the reaction temperature is higher than the sintering temperature of the prepared ultrafine titanium oxide. Although there is heat radiation from the reaction apparatus, the fine particles of the produced titanium oxide are sintered unless they are rapidly cooled after the reaction, resulting in grown particles. In the present invention, the high temperature residence time exceeding 600 ° C in the reaction tube is 3 seconds or less, preferably 1 second or less, particularly preferably 0.5 seconds or less, and then quenched after that.

As means for quenching the particles after the reaction, a large amount of cooling air or a gas such as nitrogen is introduced into the mixture after the reaction, or water is sprayed.

Fig. 1 shows a schematic diagram of a reaction tube having a coaxial parallel flow nozzle used for producing the titanium oxide of the present invention. The gas containing titanium tetrachloride is preheated to the predetermined temperature by the preheater 2, and introduced into the reaction tube 3 from the inner tube of the coaxial parallel flow nozzle portion 1. The oxidizing gas is preheated to the predetermined temperature by the preheater 2 and introduced into the reaction tube 3 from the appearance of the coaxial parallel flow nozzle unit 1. In addition, in this invention, the temperature of the preheater 2 is the same, different, or respectively, respectively. The gas introduced into the reaction tube 3 is mixed and reacted, quenched with a cooling gas, and then sent to the bug filter 4 to collect particulate titanium oxide.

Example

Hereinafter, although it demonstrates concretely using an Example, this invention is not limited to these Examples.

Example 1

Gas containing titanium tetrachloride 11.8Nm ³ / hour in concentration 100% (N stands for standard state, i.e. 0 ° C, 760mmHg. The same below) at 1,000 ° C, 8Nm ³ / hour of oxygen and 20Nm ³ / The mixed gas of steam of time was preheated to 1,000 degreeC, respectively, and it introduce | transduced into the reaction tube at the flow rates of 49 m / sec and 60 m / sec using the coaxial parallel flow nozzle, respectively. However, the reaction used the reaction tube as shown in FIG. 1, the coaxial parallel-flow nozzle inner tube diameter was 20 mm, and the gas containing titanium tetrachloride was introduce | transduced into the inner tube.

The inner diameter of the reaction tube was 100 mm, and the flow velocity in the tube at the reaction temperature of 1,320 ° C. was 10 m / sec. After the reaction, cooling air is introduced into the reaction tube so that the high temperature residence time in the reaction tube is 0.3 seconds or less, and thereafter, particulate powder produced using a Teflon bug filter is collected.

The obtained titanium oxide fine particles were fine particles having a BET specific surface area of 14 m ² / g. In addition, the 90% cumulative weight particle size distribution diameter D90 in the particle size distribution measured by the laser diffraction particle size distribution measuring method for the obtained titanium oxide fine particles was 0.8 μm, and the n value in the rosin-lamellar type was 2.8. In addition, n-values were obtained by three points of data, D10, D50, and D90 obtained by laser diffraction, respectively, as R = 90%, 50%, and 10% in the RR (Rosin-Lambler) diagram, respectively. It was.

<Example 2>

Gas containing titanium tetrachloride mixed with gaseous titanium tetrachloride 8.3Nm ³ / hour and nitrogen 6Nm ³ / hour is 800 ° C, and an oxidizing gas with oxygen 4Nm ³ / hour and water vapor 15Nm ³ / hour is mixed at 900 ° C. Each was preheated and introduced into the reaction tube at a flow rate of 50 m / sec and 38 m / sec, respectively, using a coaxial parallel flow nozzle. However, the coaxial parallel flow nozzle inner tube diameter was 20 mm, and the gas containing titanium tetrachloride was introduce | transduced into an inner tube.

The inner diameter of the reaction tube was 100 mm, and the flow velocity in the tube was 8 m / sec at a calculated temperature of 1,200 占 폚. After reaction, cooling air was introduce | transduced into a reaction tube so that the high temperature residence time in a reaction tube might be 0.2 second or less, and the particulate powder was collected using the Teflon bug filter after that.

The obtained titanium oxide fine particles were fine particles having a BET specific surface area of 78 m ² / g. For the obtained titanium oxide fine particles, the 90% cumulative weight particle size distribution diameter D90 in the particle size distribution measured by the laser diffraction particle size distribution measuring method was 1.4 μm, and the n value in the rosin-lamellar formula obtained as in Example 1 was 2.1. .

When the obtained titanium oxide fine particles were irradiated with a transmission electron microscope (TEM), the non-spherical or irregular particle shown in the TEM photograph of FIG. 2 was observed.

Example 3

Gaseous titanium tetrachloride 4.7Nm ³ / hour and nitrogen 16Nm ³ / hour mixed with the gas containing titanium tetrachloride comprising the 1,100 ℃, air 20Nm ³ / hour and water vapor 25Nm ³ / hour and mixed with an oxidizing gas comprising 1,000 Each was preheated to ° C and introduced into the reaction tube at a flow rate of 92 m / sec and 97 m / sec, respectively, using a coaxial parallel flow nozzle. However, the coaxial parallel flow nozzle inner tube diameter was 20 mm, and the gas containing titanium tetrachloride was introduce | transduced into an inner tube.

The inner dimension of the reaction tube was 100 mm, and the flow velocity in the tube at the reaction temperature of 1,250 ° C. was 13 m / sec. After reaction, cooling air is introduce | transduced into a reaction tube so that high temperature residence time may be 0.2 second in a reaction tube, and fine particle powder is collected using a Teflon bug filter after that.

The obtained titanium oxide microparticles | fine-particles were microparticles | fine-particles whose BET phase specific surface area is 115 m <^2> / g. The titanium oxide fine particles thus obtained had a 90% cumulative weight particle size distribution diameter D90 of 2.1 μm in the particle size distribution measured by the laser diffraction particle size distribution measuring method, and the n value in the rosin-lamellar formula obtained as in Example 1 was 1.8. .

<Comparative Example 1>

The gaseous titanium tetrachloride 11.8Nm ³ / hour of the concentration of 100% to 400 ℃, respectively preheat the oxidizing gas is a mixture of oxygen 8Nm ³ / hour and water vapor 20Nm ³ / hour to 850 ℃, and using a coaxial parallel flow nozzle, The reaction tubes were introduced at a flow rate of 26 m / sec and 40 m / sec, respectively. However, the coaxial parallel flow nozzle inner tube diameter was 20 mm, and the gas containing titanium tetrachloride was introduce | transduced into an inner tube.

The inner dimension of the reaction tube was 100 mm, and the flow velocity in the tube at the reaction temperature of 680 ° C. was 5.6 m / sec. After the reaction, cooling air is introduced into the reaction tube so that the high temperature residence time in the reaction tube is 0.3 seconds or less, and thereafter, particle powder is collected using a Teflon bug filter.

The obtained titanium oxide particles were particles having a BET specific surface area of 8 m ² / g. In the particle size distribution measured by the laser diffraction particle size distribution measurement method, the obtained titanium oxide particles had a 90% cumulative weight particle size distribution diameter D90 of 11 µm, and the n value in the rosin-lamer's equation obtained in the same manner as in Example 1 was 1.1. .

Compared with Example 1, this value is larger in both primary and secondary particle diameters, and the particle size distribution is wider.

<Comparative Example 2>

Each preheated gaseous titanium tetrachloride 11.8Nm ³ / hour of the concentration of 100% to 1,000 ℃, the oxidizing gas is mixed with oxygen 8Nm ³ / hour and water vapor 20Nm ³ / hour to 1,000 ℃, and using a coaxial parallel flow nozzle, The reaction tubes were introduced at flow rates of 5.4 m / sec and 23 m / sec, respectively. However, the coaxial parallel flow nozzle inner tube diameter was 60 mm, and the gas containing titanium tetrachloride was introduce | transduced into an inner tube.

The inner dimension of the reaction tube was 100 mm, and the flow velocity in the tube at the reaction temperature of 1,320 ° C. was 10 m / sec. After the reaction, cooling air is introduced into the reaction tube so that the high temperature residence time in the reaction tube is 0.3 seconds or less, and thereafter, particle powder is collected using a Teflon bug filter.

The obtained titanium oxide particles were particles having a BET specific surface area of 8 m ² / g. For the titanium oxide particles thus obtained, the 90% cumulative weight particle size distribution diameter D90 in the particle size distribution measured by the laser diffraction particle size distribution measuring method was 2.3 μm, and the n value in the rosin-lamer's equation obtained in the same manner as in Example 1 was 1.6. It was.

Compared with Example 1, this value is larger in both the primary and secondary particle diameters, and the particle size distribution is wider.

<Comparative Example 3>

The gaseous titanium tetrachloride 11.8Nm ³ / hour of the concentration of 100% to 1,000 ℃, and respectively preheat the oxidizing gas is mixed with oxygen 8Nm ³ / hour and water vapor 20Nm ³ / hour in 1, 000 ℃, using a coaxial parallel flow nozzle And introduced into the reaction tube at a flow rate of 49 m / sec and 32 m / sec, respectively. However, the inner tube diameter of the coaxial parallel flow nozzle was set to 20 mm, and a gas containing titanium tetrachloride was introduced into the inner tube.

The inner diameter of the reaction tube was 100 mm, and the flow velocity in the tube at the reaction temperature of 1,320 ° C. was 14 m / sec. After the reaction, cooling air is introduced into the reaction tube so that the high temperature residence time is 2 seconds in the reaction tube, and thereafter, particle powder is collected using a Teflon bug filter.

The obtained titanium oxide particles were particles having a BET specific surface area of 8 m ² / g. For the titanium oxide particles thus obtained, the 90% cumulative weight particle size distribution diameter D90 in the particle size distribution measured by the laser diffraction particle size distribution measurement method was 1.8 µm, and the n value in the rosin-lamellar equation obtained in the same manner as in Example 1 was obtained. It was 2.0.

Compared with Example 1, this value is larger in both primary and secondary particle diameters, and the particle size distribution is wider.

<Comparative Example 4>

The gaseous titanium tetrachloride 11.8Nm ³ / hour of the concentration of 100% to 1,000 ℃, respectively preheat the oxidizing gas is mixed with oxygen 8Nm ³ / hour and water vapor 20Nm ³ / hour to 1,000 ℃, and using a coaxial parallel nozzle, respectively, A flow rate of 49 m / sec and 60 m / sec was introduced into the reaction tube. However, the coaxial parallel flow nozzle inner tube diameter was 20 mm, and the gas containing titanium tetrachloride was introduce | transduced into an inner tube.

The inner diameter of the reaction tube was 250 mm, and the flow velocity in the tube was 1.6 m / sec at a calculated value of 1,320 占 폚. After the reaction, cooling air is introduced into the reaction tube so that the high temperature residence time in the reaction tube is 0.3 seconds or less, and thereafter, particle powder is collected using a Teflon bug filter.

The obtained titanium oxide particles were particles having a BET specific surface area of 9 m ² / g. Moreover, about the obtained titanium oxide, 90% cumulative weight particle size distribution diameter D90 in the particle size distribution measured by the laser diffraction type particle size distribution measuring method was 4.2 micrometer, n value in the rosin-lambler formula calculated like Example 1 was 1.4.

Compared with Example 1, this value is larger in both the primary and secondary particle diameters, and the particle size distribution is wider.

<Comparative Example 5>

The gaseous titanium tetrachloride 11.8Nm ³ / hour of the concentration of 100% to 400 ℃, respectively preheat the oxidizing gas is mixed with oxygen 8Nm ³ / hour and water vapor 20Nm ³ / hour to 500 ℃, and using a coaxial parallel nozzle, respectively, It was introduced into the reaction tube at a flow rate of 46 m / sec and 40 m / sec. However, the coaxial parallel flow nozzle inner tube diameter was 15 mm, and the gas containing titanium tetrachloride was introduce | transduced into an inner tube.

The inner diameter of the reaction tube was 100 mm, and the flow velocity in the tube at the reaction temperature of 550 ° C. was 5.3 m / sec. After the reaction, cooling air is introduced into the reaction tube so that the high temperature residence time in the reaction tube is 0.3 seconds or less, and thereafter, particle powder is collected using a Teflon bug filter.

The obtained titanium oxide particles were particles having a BET specific surface area of 7 m ² / g. Moreover, about the obtained titanium oxide particle, 90% cumulative weight particle size distribution diameter D90 in the particle size distribution measured by the laser diffraction type particle size distribution measuring method was 15 micrometers, and n value in the rosin-lambler formula calculated like Example 1 was 0.9.

Compared with Example 1, this value is larger in both the primary and secondary particle diameters, and the particle size distribution is wider.

As described above, according to the present invention, in the gas phase method of producing titanium oxide by high temperature oxidation of titanium tetrachloride with an oxidizing gas, a gas containing titanium tetrachloride and an oxidizing gas are respectively preheated to 500 ° C. or higher. by reacting the then supplied to the reaction tube, the fine particles onto the dispersibility is excellent, BET specific surface area of 3~200m ² / g of microparticulate titanium oxide, especially having a BET specific surface area 5~200m ² / g, a BET specific surface area also Ultrafine particulate titanium oxide of 10 to ²⁰⁰ m ² / g was obtained.

In addition, since the particulate titanium oxide of the present invention has a sharp particle size distribution and excellent dispersibility in hydrophilic solvents, a disintegration step or the like is unnecessary or very light, and has a very large practical value. will be.

The invention may be practiced in other specific embodiments without departing from its essential features. Accordingly, the present embodiments are to be considered in all respects only as illustrative and not restrictive, and the scope of the present invention is to be described by the appended claims rather than the foregoing description, and therefore, all modifications falling within the scope of equivalents of the claims are the present invention. It is included in.

1 is a schematic diagram of a reaction tube having a coaxial parallel flow nozzle.

FIG. 2 is a TEM photograph of titanium oxide obtained in Example 2. FIG.

Claims (2)

Titanium oxide fine particles having a BET specific surface area of 3 m ² / g to 200 m ² / g and a 90% cumulative weight particle size distribution diameter D 90 of 2.2 μm or less. A composition containing titanium oxide fine particles having a BET specific surface area of 3 m ² / g to 200 m ² / g and a 90% cumulative weight particle size distribution diameter D 90 of 2.2 μm or less.