KR100493906B1 - A titanium oxide composition comprising particulate titanium oxide - Google Patents

Abstract

A composition containing particulate titanium oxide is provided. Titanium oxide contained in the composition of the present invention is a mixed crystal titanium oxide containing rutile crystals produced by a gas phase method, the following formula,

R≥1300 × B ^-0.95

[Wherein, R represents rutile content (%) and B represents BET specific surface area (m 2 / g).]

It is a particulate titanium oxide which has the characteristic shown by these.

This titanium oxide is a high rutile-containing titanium oxide in the form of highly dispersible fine particles with very small aggregation.

Description

A composition containing particulate titanium oxide {A TITANIUM OXIDE COMPOSITION COMPRISING PARTICULATE TITANIUM OXIDE}

TECHNICAL FIELD This invention relates to the composition containing particulate titanium oxide suitable for a sunscreen use, a photocatalyst use, etc. More preferably, the present invention relates to a composition containing ultrarutile titanium oxide containing ultrafine particles obtained by vapor phase method using titanium tetrachloride as a raw material.

Industrial applications of particulate titanium oxide, in particular ultrafine titanium oxide, are very wide, and their applications include ultraviolet shielding materials, additives to silicone rubbers, photocatalysts, and the like. (JIS) is described as "titanium dioxide," and is commonly used herein as "titanium oxide", so it is abbreviated herein as titanium oxide.) Especially in the field of cosmetics and clothing materials, Its use is considered to be more important in recent years, and as a shielding material, ultrafine titanium oxide has high safety and is frequently used. Shielding requires two functions: ultraviolet absorption and scattering, but ultrafine titanium oxide has both functions.

There are three crystalline forms of titanium oxide: brute kite, anatase and rutile, and anatase and rutile are of particular industrial importance. In addition, since the band gap (corresponding to excitation energy) of rutile is smaller than that of anatase (the absorption wavelength range of light is longer than that of anatase), rutile is preferable for ultraviolet ray shielding applications. However, in addition to this absorption, the present invention also needs to cope with scattering effects depending on the particle diameter.

In recent years, titanium oxide absorbs ultraviolet rays of about 400 nm or less to excite the outermost electrons, and electrons and holes generated at this time reach the particle surface and combine with oxygen or water to generate various radical species. It is reported that there is an action of decomposing organic matter present in the vicinity. For this reason, when titanium oxide is used in cosmetics or the like, it is generally attempted to surface-treat the surface of the titanium oxide surface in the form of fine particles, particularly ultrafine particles.

In addition, in order to utilize the photocatalytic reaction by photoexcitation of titanium oxide, particulate titanium oxide is used. In addition, 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 the fine particles of 0.1㎛ or less.

The production method of titanium oxide is roughly a liquid phase method of hydrolyzing in a hydrophilic solvent using titanium tetrachloride or titanium sulfate as a raw material, or vaporizing a volatile raw material such as titanium tetrachloride and reacting it with an oxidizing gas such as oxygen or water vapor. There is a vapor phase method. In the vapor phase method, ultrafine titanium oxide is obtained, but only anatase is obtained as a main phase. Therefore, conventionally, ultrafine titanium oxide having a rutile structure is obtained by a gas phase method.

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

Several methods for producing gorutile-containing titanium oxide have been proposed. For example, Japanese Patent Application Laid-Open No. 3-252315 discloses a production method for adjusting the content of rutile by changing the ratio of hydrogen in a mixed gas of oxygen and hydrogen in a gas phase reaction, and the hydrogen concentration to 15 to 17% by volume. A method of producing high purity titanium oxide having a rutile content of 99% or more by adjusting is disclosed. Further, Japanese Patent Laid-Open No. Hei 6-340423 discloses a high rutile-containing titanium oxide (rutile content of 85 wt% to 90 wt%) prepared by using a molar ratio of titanium tetrachloride, hydrogen and oxygen in a mixed gas as a specific mixing ratio. A manufacturing method is disclosed.

In addition, even 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 titanium oxide particles grown in grains are obtained, so that titanium oxide is obtained in order to obtain particulate titanium oxide. It needs to be pulverized or crushed strongly, and had the same problem as the liquid phase method. In addition, in the high rutile-containing titanium oxide, although it is an ultra-fine particle | grain, the specific surface area is not enough and it was not enough in the point of the dispersibility which is desired for various uses including cosmetics.

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 very high dispersibility, as a particulate form having a very small aggregation, especially an ultrafine grain form.

Another object of the present invention is to provide a method for producing a high rutile-containing titanium oxide in the form of such particulates, in particular ultrafine particles.

The present inventors earnestly studied the above problems, and in the gas phase method, the titanium tetrachloride dilution gas and the oxidizing gas diluted with titanium tetrachloride with an inert gas were respectively preheated and supplied to the reaction tube at a specific flow rate, and at a specific high temperature residence time. By reacting, it was found that the high rutile-containing titanium oxide having a specific characteristic having a high BET specific surface area as a high rutile-containing titanium oxide, in particular ultrafine particles, was obtained, thereby completing the present invention.

That is, the present invention relates to the following [1] to [10].

[1] A mixed titanium oxide containing rutile crystals produced by a gas phase method, wherein the titanium oxide is represented by the following general formula

R≥1300 × B ^-0.95

In the formula, R represents the rutile content (%) measured by the X-ray diffraction method, B represents the BET specific surface area (m 2 / g), the range of which is 15 to 200 m 2 / g.] Particulate titanium oxide, characterized by having.

[2] The particulate titanium oxide according to the above 1 item, wherein the BET specific surface area represented by B is 40 to 200 m 2 / g.

[3] The particulate titanium oxide according to claim 1 or 2, wherein the titanium oxide has a 90% cumulative weight particle size distribution diameter D90 measured by a laser diffraction particle size distribution measurement method of 2.5 µm or less.

[4] The particulate titanium oxide according to any one of the above items 1 to 3, wherein the titanium oxide has a distribution constant n of 1.5 or more according to a Rosin-Rammler formula.

[5] A gas phase method for producing titanium oxide by subjecting titanium tetrachloride dilution gas obtained by diluting titanium tetrachloride to an inert gas to 10 vol% or more and 90 vol% or less at high temperature using oxygen or steam or an oxidizing gas containing them, at 900 ° C. The titanium tetrachloride dilution gas and the oxidizing gas preheated above are respectively supplied to the reaction tube at a flow rate of 20 m / sec or more, and the high temperature residence time exceeding 700 ° C. is reacted for 3 seconds or less. Manufacturing method.

[6] A method for producing the particulate titanium oxide according to item 5, wherein a titanium tetrachloride dilution gas obtained by diluting titanium tetrachloride to 20 vol% or more and 80 vol% or less is used.

[7] The method for producing particulate titanium oxide according to claim 5 or 6, wherein the respective temperatures for preheating the titanium tetrachloride diluent gas and the oxidizing gas are 1,000 ° C or higher.

[8] The titanium tetrachloride diluent gas and the oxidizing gas are supplied into the reaction tube by a coaxial parallel flow nozzle, and the inner diameter of the outer coaxial parallel flow nozzle inner tube is 50 mm or less. The manufacturing method of the particulate titanium oxide of Claim.

[9] A particulate titanium oxide, which is produced using the method for producing particulate titanium oxide according to any one of items 5 to 8.

[10] A titanium oxide composition comprising the particulate titanium oxide according to any one of items 1 to 4 and 9.

According to the present invention, a mixed crystal titanium oxide containing a rutile crystal obtained by a gas phase method using titanium tetrachloride as a raw material (abbreviated as "rutile-containing titanium oxide") is characterized by the following formula (1). ),

R≥1300 × B ^-0.95

In the formula, R represents the rutile content (%) measured by the X-ray diffraction method, B represents the BET specific surface area (m 2 / g), the range of which is 15 to 200 m 2 / g.] It is characterized by having. That is, the particulate, particularly ultrafine, rutile-containing titanium oxide of the present invention is rutile-containing titanium oxide that satisfies the condition of the formula (1) in FIG. 2. Known particulate or ultrafine titanium oxide had properties of regions plotted at the bottom of the curve R = 1300 × B- ^0.95 , even in the case of rutile-containing titanium oxide, in the relationship between the rutile content ratio and the BET specific surface area.

The rutile-containing titanium oxide of the present invention satisfies the characteristics of the formula (1), and is a fine particle, in particular, an ultrafine particle, and the BET specific surface area is 15 to 200 m 2 / g, preferably 40 to 200 m 2 / It has a range of g.

In addition, the fine particle rutile-containing titanium oxide of the present invention preferably has a small particle size and a sharp particle size distribution. In the present invention, the particle size distribution was measured by employing a laser diffraction particle size distribution measuring method as an index of dispersibility. The measurement procedure of particle size distribution is demonstrated below.

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

The particulate titanium oxide of the present invention is excellent in uniformity of particle size distribution. In the present invention, the uniformity of the particle size distribution is defined by the distribution constant n using the Rosin Lamber equation. The rosin lamber type will be briefly described below, but the details thereof are described in the Ceramic Engineering Handbook (Kabushikishaki Nippon Ceramic Kyokai, First Edition, pages 596 to 598).

The rosin Lamber equation is represented by the following equation (2).

R = 100exp (-bD ⁿ ) (2)

Wherein D represents a particle diameter, R is a percentage of the total number of particles larger than D, and n is a distribution integer.

In this case, if b = 1 / De ⁿ , (2)

R = 100exp {-(D / De) ⁿ } (3)

Can be replaced with However, De is a particle size characteristic number, n is an integer called a distribution constant. In the formula (2), the constant b is obtained from the particle size and distribution constant n for the particle size characteristic De, i.e., an ober particle diameter of 36.8% (R = 1 / e = 0.368). De ⁿ ).

The formula (4) is obtained from the formula (2) or (3).

log { log (100 / R)} = n log D + C (4)

However, in formula, C represents an integer. From the above formula (3), when these relations are plotted on a rosin lamber (RR) diagram showing a scale of 1og D on the x-axis and 1og { log (100 / R)} on the y-axis, it becomes almost a straight line. 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 2.5 micrometers or less, and it is preferable that distribution constant n by a rosin ramler formula is 1.5 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 as an additive for various products such as cosmetics, medical care, ultraviolet shielding materials or silicone rubber.

Next, the manufacturing method of particulate titanium oxide of this invention is demonstrated with reference to drawings. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic schematic diagram of the reaction tube provided with the coaxial parallel flow nozzle used for the manufacturing method of particulate titanium oxide of this invention by the gas phase method. 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. In addition, in this invention, the temperature of each preheater 2 may differ. 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. The gas introduced into the reaction tube is mixed and reacted, cooled with a cooling gas, and then sent to the bag filter 4 to collect particulate titanium oxide.

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 a reaction condition at about 1,000 ° C, particulate titanium oxide is obtained.

In the gas phase method, there are two types of growth mechanisms of particles, 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 as an object of the present invention, all of these growth times (growth zones) must be shortened. That is, in the former growth, the growth can be suppressed by increasing the chemical reactivity (reaction rate) each time the preheating temperature is increased. In the latter growth, growth by sintering or the like can be suppressed by performing rapid cooling, dilution or the like after CVD is completed and minimizing the high temperature residence time as much as possible.

On the other hand, when it is going to obtain the particle | grains with a high rutile content rate, it is necessary to fully take the high temperature residence time, in order to promote the heat potential from anatase. This contradicts the conditions for producing the aforementioned fine particles, in particular ultra-fine particles.

Therefore, the microparticles | fine-particles or ultrafine particles obtained by the vapor phase method conventionally have anatase as a columnar or amorphous thing.

In the present invention, as described above, in the gas phase method of producing titanium oxide by oxidizing a titanium tetrachloride dilution gas obtained by diluting titanium tetrachloride with an inert gas to 90% or less at high temperature with the oxidizing gas, tetrachloride preheated to 900 ° C or more. The titanium dilution gas and the oxidizing gas are respectively supplied to the reaction tube at a flow rate of 20 m / sec or more, and the average residence time is reacted at 3 seconds or less, so that the fine rutile content of the high rutile content in the relationship between the BET specific surface area and the rutile content, in particular, Ultrafine particulate titanium oxide is obtained.

In the present invention, the titanium tetrachloride concentration in the titanium tetrachloride dilution gas is preferably 10 to 90% by volume, more preferably 20 to 80% by volume. If the titanium tetrachloride concentration is 10% or less, the reactivity is low and the rutile content does not increase. On the other hand, when the titanium tetrachloride concentration is 90% by volume or more, the collision and sintering of the particles are encouraged, and the desired fine particle, in particular, ultrafine titanium oxide is not obtained.

Gases which dilute titanium tetrachloride should be chosen not to react with titanium tetrachloride and not to be oxidized. Specifically, nitrogen, argon, etc. are mentioned.

The preheating temperature of the titanium tetrachloride diluent gas and the oxidizing gas may be the same or different, but each is preferably 900 ° C. or higher. Further, the temperature is preferably 1,000 ° C. or higher, and particularly preferably about 1,100 ° C. However, although the smaller the preheating temperature difference of each gas is, the lower the preheating temperature of the target gas is lower than 900 ° C, the lower the reactivity around the nozzle and the higher the rutile content is.

The flow rate for introducing the titanium tetrachloride diluent gas and the oxidizing gas into the reaction tube is preferably 20 m / sec or more, more preferably 30 m / sec or more, particularly preferably 50 m / sec or more. By increasing the flow rate, mixing of both gases is promoted. When the introduction temperature is 900 ° C or higher, the reaction is completed at the same time as mixing, so that uniform nucleation is promoted, and the reaction zone (zone in which grown particles are formed by CVD domination) can be reduced. If the flow rate is less than 20 m / sec, the mixing is insufficient and thus does not become the desired fine particles, especially ultra fine particles. Moreover, as an introduction nozzle, the nozzle which applies coaxial parallel flow, cross flow, cross flow, etc. is employ | adopted.

It is preferable that the preheated titanium tetrachloride diluent gas and the oxidizing gas are supplied into the reaction tube to generate vigorous air in the reaction tube. The titanium tetrachloride diluent gas and the oxidizing gas are supplied into the reaction tube by the coaxial parallel flow nozzle, and the inner diameter of the inner tube of the outer coaxial parallel flow nozzle is preferably 50 mm or less.

On the other hand, when the source gas is introduced into the reaction tube and the reaction proceeds, since the present invention is an exothermic reaction, there is a reaction zone (region) in which the reaction temperature exceeds 1,000 ° C. Although the device dissipates somewhat, titanium oxide particles grow rapidly unless quenched. Moreover, in this invention, it is preferable to suppress the high temperature residence time over 700 degreeC to 3 second or less, Preferably it is 1 second or less, Especially preferably, it is 0.5 second or less, and then quench after that. If the high temperature residence time exceeds 3 seconds, the sintering of the particles proceeds, which is not preferable.

As means for quenching the titanium oxide particles after the reaction, a method of introducing a large amount of gas such as cooling air or nitrogen into the reaction mixture, a method of spraying water, or the like is adopted.

The particulate titanium oxide of the present invention, particularly ultrafine titanium oxide, is sharp in particle size distribution and excellent in dispersibility in aqueous solvents, and thus is suitable for ultraviolet ray shielding applications in cosmetics and medical fields. Therefore, the particulate titanium oxide of the present invention can be mixed with known carriers, additives and the like used in these fields to obtain a composition that can be used for ultraviolet shielding.

Example

Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to an Example.

(Example 1)

Titanium tetrachloride diluted gas of 11.8 Nm 3 / hr (N is the standard state, which is the same below) diluted with 4 Nm 3 / hr nitrogen gas was preheated to 1,100 ° C., and 8 Nm 3 / hr of The oxidizing gas mixed with oxygen and 20 Nm 3 / hr steam was preheated to 1,000 ° C., and these raw material gases were respectively fed to a quartz glass reactor through a coaxial parallel flow nozzle using a reaction apparatus as shown in FIG. 2. It was introduced at a flow rate of 40 m / sec and 30 m / sec. Cooling air was introduced into the reactor so that the high temperature residence time over 700 ° C was 0.3 seconds, and then particulate powder of titanium oxide was collected by a Teflon bag filter.

The obtained titanium oxide fine particles were fine particles having a BET specific surface area of 20 m 2 / g and a rutile content ratio (also called rutile content) of 92%. However, the BET specific surface area is measured by a specific surface area measuring apparatus manufactured by Shimadzu Seisakusho (type is Flosov II, 2300), and the rutile content ratio is the peak area corresponding to the rutile crystal in X-ray diffraction (abbreviated as Sr). And peak area (abbreviated as "Sa") corresponding to the anatase type crystal (= 100 x Sr / (Sr + Sa)). The rutile content rate is much larger than the value calculated by substituting 20 m 2 / g of specific surface area in formula (1).

The particle size distribution of the titanium oxide fine particles obtained here was measured by a laser diffraction particle size distribution measurement method and the 90% cumulative weight particle size distribution diameter D90 was 1.2 µm, and the n value was 2.3 in the rosin lamber equation.

In addition, the n value was plotted as three points of data, D10, D50, and D90 obtained by laser diffraction as R = 90%, 50%, and 10% in the RR diagram, respectively, and was obtained from the approximation lines of these three points.

(Example 2)

Titanium tetrachloride diluted gas diluted with 8.3 Nm 3 / hr gaseous titanium tetrachloride with 6 Nm 3 / hr nitrogen gas was preheated to 1,100 ° C., and 4 Nm 3 / hr oxygen and 15 Nm 3 / hr steam were mixed. The oxidizing gas was preheated to 1,100 ° C. and these source gases were introduced into the quartz glass reactor at a flow rate of 35 m / sec and 50 m / sec, respectively, through a coaxial parallel flow nozzle using a reactor as shown in FIG. 2. . After introducing cooling air into the reaction tube so that the high temperature residence time over 700 degreeC may be 0.2 second, the fine particle powder of titanium oxide was collected with the Teflon bag filter.

The obtained titanium oxide fine particles were fine particles having a BET specific surface area of 55 m 2 / g and a rutile content of 45%. This rutile content rate is much larger than the value computed by substituting 55 m <2> / g of specific surface areas in Formula (1). In the particle size distribution measured by the laser diffraction particle size distribution measurement method of this powder, 90% of the cumulative weight particle size distribution diameter D90 was 1.4 µm, and the n value was 2.0 in the rosin rammer formula.

(Example 3)

Titanium tetrachloride diluted gas diluted 4.7 Nm 3 / hr gaseous titanium tetrachloride to 16 Nm 3 / hr cumulative gas was preheated to 1,100 ° C, and 20 Nm 3 / hr air and 25 Nm 3 / hr steam were mixed. The oxidizing gas was preheated to 1,000 ° C., and these source gases were introduced into the quartz glass reactor at a flow rate of 45 m / sec and 60 m / sec, respectively, through a coaxial parallel flow nozzle using a reaction apparatus as shown in FIG. 2. . Cooling air was introduced into the reactor so that the high residence time over 700 ° C. was 0.2 seconds, and then particulate powder of titanium oxide was collected by a Teflon bag filter.

The obtained titanium fine particles were fine particles having a BET specific surface area of 115 m 2 / g and a rutile content of 20%. This rutile content rate is much larger than the value computed by substituting 115 m <2> / g of specific surface areas in Formula (1). In addition, in the particle size distribution measured by the laser diffraction type particle size distribution measuring method of this powder, 90% cumulative weight particle size distribution diameter D90 was 2.1 micrometers, and n value was 1.8 in rosin-lambler formula.

(Comparative Example 1)

Titanium tetrachloride diluted gas diluted with 8.3 Nm 3 / hr gaseous titanium tetrachloride with 6 Nm 3 / hr nitrogen gas was preheated to 800 ° C., and 4 Nm 3 / hr oxygen and 15 Nm 3 / hr steam were mixed. The oxidizing gas is preheated to 900 ° C., and these source gases are introduced into a quartz glass reactor through a coaxial parallel flow nozzle using a reaction apparatus as shown in FIG. 2, followed by fine particles of titanium oxide with a Teflon bag filter. The powder was collected.

The obtained titanium oxide fine particles were fine particles having a BET specific surface area of 21 m 2 / g and a rutile content of 26%. This rutile content rate is much smaller than the value computed by substituting 21 m <^2> / g of specific surface areas in Formula (1). In the particle size distribution measured by the laser diffraction particle size distribution measurement method of the powder, the 90% cumulative weight particle size distribution diameter D90 was 2.1 µm, and the n value was 1.8 in the rosin lamber equation.

(Comparative Example 2)

The ultrafine powdered titanium oxide P-25 manufactured by Nippon Bon Aerodyl Kabushi Kaisha was analyzed, and the specific surface area was 54 m 2 / g and the rutile content was 15%. This rutile content rate shows the numerical value smaller than the value computed by substituting 54 m <2> / g of specific surface areas in General formula (1). Moreover, in the particle size distribution measured by the laser diffraction type particle size distribution measuring method of this powder, 90% cumulative weight particle size distribution diameter D90 was 3.1 micrometers, and n value was 1.4 in the rosin-lambler formula.

The ultrafine titanium oxide IT-S manufactured by Idemitsuko Kabuki Kaisha Co., Ltd. was analyzed and found to have a specific surface area of 108 m 2 / g and a rutile content of 0% (amorphous). The value calculated by substituting the specific surface area of 108 m 2 / g in the formula (1) represents about 16%.

In the particle size distribution of the powder, the 90% cumulative weight particle size distribution diameter D90 was 6.3 µm, and the n value was 1.8 in the rosin lamber formula, as measured by a laser diffraction particle size distribution measurement method.

The particulate, particularly ultrafine, titanium oxide of the present invention satisfies the condition of the formula (1) in the correlation between the BET specific surface area (B) and the rutile content (R). In addition, the fine rutile-containing titanium oxide obtained by the production method of the present invention has a much higher rutile content and is particularly excellent in dispersibility than other titanium oxides having an equivalent BET specific surface area.

In addition, the ultrafine titanium oxide having such characteristics preferably has a 90% cumulative weight particle size distribution diameter D90 of 2.5 μm or less measured by a laser diffraction dispersion measurement method, and furthermore, a distribution constant n of the rosin lamber equation is 1.5 or more. desirable.

The ultrafine titanium oxide having the characteristics of the present invention is suitable for ultraviolet ray shielding applications and the like in cosmetics and medical fields. In addition, since the particle size distribution is sharp and the dispersibility of the aqueous solvent is excellent, the disintegration step or the like is unnecessary or extremely light, and has a great practical value industrially.

The invention can be practiced in other specific embodiments without departing from its essential features. Accordingly, the present embodiments are to be considered in all respects as illustrative and not restrictive, and the scope of the present invention is indicated by the appended claims rather than the foregoing description, and therefore all changes that fall within the scope of the claims are equivalent. All are included in this invention.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the characteristic range of the ultrafine particle rutile containing titanium oxide of this invention in the relationship between rutile content rate of ultrafine titanium oxide, and BET specific surface area.

FIG. 2 is a schematic diagram of a reaction tube having a coaxial parallel flow nozzle used in Example 2. FIG.

Claims (4)

A composition containing particulate titanium oxide, wherein the titanium oxide is a mixed crystal titanium oxide containing rutile crystals produced by a gas phase method, R≥1300 × B ^-0.95 [Wherein R represents a rutile content (%) measured by X-ray diffraction method, B represents a BET specific surface area (m ² / g), and the range thereof is 15 to 200 m 2 / g.] A composition containing particulate titanium oxide, characterized in that represented by. The composition according to claim 1, wherein the BET specific surface area represented by B is 40 m 2 / g to 200 m 2 / g. The composition according to claim 1, wherein the titanium oxide has a 90% cumulative weight particle size distribution diameter D90 of more than 0 µm and 2.5 µm or less as measured by a laser diffraction particle size distribution measurement method. The composition according to claim 1, wherein the titanium oxide has a distribution constant n of 1.5 or more according to a rosin lamber equation.