Titanium oxide powder and method for producing the same

Abstract

The present application provides a titanium oxide powder characterized in that the ratio (I A / I R ) of the peak intensity (I A ) of an anatase crystal to the peak intensity (I R ) of a rutile crystal in X-ray diffraction measurement is 0.1 or less; the average minor axis length of the contained particles is 10 to 50 nm, and the average ratio of major axis to minor axis is 1 to 3; the ratio (A 450 / A 320 ) of the absorbance A 450 at a wavelength of 450 nm to the absorbance A 320 at a wavelength of 320 nm is 0.015 to 0.5; and nitrogen atoms are contained, and a peak from the nitrogen atoms is observed at 395 to 402 eV in ESCA (Electron Spectroscopy for Chemical Analysis) measurement. Thus, a titanium oxide powder can be provided, which is mainly composed of a rutile crystal, has excellent UVA shielding effect, is highly safe for the human body, and has a good color tone.

Description

TECHNICAL FIELD

[0001] The present application relates to titanium oxide powder, its use, and a method for producing the same. BACKGROUND

[0002] Sunburn caused by ultraviolet rays can cause adverse effects on the skin, and thus sunburn-preventing cosmetics are widely used. In addition, not only sunburn-preventing cosmetics, but also in most cases, ultraviolet ray shielding effects are required in color cosmetics. In response to this, cosmetics in which inorganic particles such as titanium oxide, zinc oxide, or organic ultraviolet absorbers are combined have been developed. Among these, titanium oxide is widely used because of its high ultraviolet ray shielding effect and because it does not easily cause skin problems such as organic ultraviolet absorbers. In particular, titanium oxide particles having a particle size of several tens of nm or less are smaller in size than the wavelength of light, and thus have excellent transmittance of visible light, and cosmetics containing the same have reduced white color from the titanium oxide and excellent transparency when used (see Patent Documents 1 to 3).

[0003] However, in order to improve transparency, the more finely divided and highly dispersed it is, the more it is affected by Rayleigh scattering. With respect to the strength of Rayleigh scattering, the smaller the particles, the stronger it is, and blue light is more easily scattered than red light, and thus when a cosmetic containing fine titanium oxide particles is applied to the skin, a bluish color is perceived. A bluish-white color is not suitable as a cosmetic because it makes the color of the skin appear unhealthy.

[0004] In response to this, there is a method for eliminating the bluish color by containing a small amount of iron oxide (Fe2O3). However, iron oxide not only exhibits yellow, which is the complement of blue, but also exhibits red, and thus it is not possible to avoid the cosmetic becoming a cloudy color, and thus a better method is needed.

[0005] In Patent Document 4, titanium oxide powder containing a rutile-type crystal doped with a divalent sulfur atom (S 2－ ) is described, which makes it possible to obtain a cosmetic that eliminates the blue color from Rayleigh scattering, has good transparency, and also has a good color tone. In addition, it is described that the average minor axis length of the particles contained in the titanium oxide powder is 4 to 13 nm, and the average ratio of the major axis to the minor axis is 2 to 7. In this way, although the transparency and the shielding effect of UVB (280 to 320 nm) can be improved by reducing the particle size, the shielding effect of UVA (320 to 400 nm) is reduced. In order to effectively suppress the deposition of melanin caused by sun exposure to maintain white skin, it is necessary to improve the shielding effect of UVA.

[0006] It is known that the shielding effect of UVA can be improved by increasing the particle diameter of the fine particulate titanium oxide. However, when the particle diameter is increased, there is a problem that transparency is reduced and whitening occurs. In addition, the spindle-shaped rutile-type titanium oxide particles, which are widely used as ultraviolet shielding use, can be increased in particle diameter by growing the crystal, but at this time, the crystal growth mainly occurs in the long axis direction, and the ratio of the major axis length to the minor axis length of the particles can be increased. In recent years, fine particles having a large ratio of the major axis to the minor axis are considered to have a safety problem for the human body for the reason that the skin irritation is strong, and the like, and for example, in the European cosmetic standards, the ratio of the major axis to the minor axis of the titanium oxide fine particles is regulated to be 4.5 or less. Therefore, the method of increasing the particle diameter of the titanium oxide only by growing the crystal has a problem.

[0007] On the other hand, a photocatalyst composed of titanium oxide nanoparticles doped with nitrogen and containing both anatase crystals and rutile crystals is described in Non-Patent Literature 1. The titanium oxide nanoparticles exhibit absorption of light of 400 to 500 nm Figure 4 b). In addition, examples in which the proportion of the rutile crystals is 18.3%, 20.2%, and 36.9% are described, and it is described that the photocatalyst activity is the most excellent in the example of 20.2% (see Table 1 and Figure 5 ). That is, it is described that the photocatalyst activity is higher when the anatase crystals are contained much more than the rutile crystals.

[0008] Prior Art Documents

[0009] Patent Documents

[0010] Patent Document 1: Japanese Patent Application Laid-Open (JP A) No. 2010-173863

[0011] Patent Document 2: Japanese Patent Application Laid-Open (JP A) No. 2011-001199

[0012] Patent Document 3: Japanese Patent Application Laid-Open (JP A) No. 2014-084251

[0013] Patent Document 4: International Publication No. 2020 / 230812

[0014] Non-Patent Literature

[0015] Non-Patent Literature 1: J. Liu et al., Catalysts, 2020, 10, 1126 SUMMARY

[0016] PROBLEMS TO BE SOLVED BY THE INVENTION

[0017] The present application has been achieved in order to solve the above-described technical problems, and has an object to provide a titanium oxide powder having rutile-type crystals as a main component, an excellent UVA shielding effect, high safety for the human body, and a good color tone. It also has an object to provide a dispersion having a good transparency and a good color tone, particularly a cosmetic. Further, the present application has an object to provide a suitable production method of the titanium oxide powder.

[0018] Technical solution for solving the above-described technical problems

[0019] The above-described technical problems can be solved by providing a titanium oxide powder having the following characteristics:

[0020] The ratio (I A / I R ) of the peak intensity (I A ) of the anatase-type crystals to the peak intensity (I R ) of the rutile-type crystals in the X-ray diffraction measurement is 0.1 or less,

[0021] The average short axis length of the contained particles is 10 to 50 nm, and the average ratio of long axis to short axis is 1 to 3,

[0022] The ratio (A 450 / A 320 ) of the absorbance A 450 at a wavelength of 450 nm to the absorbance A 320 at a wavelength of 320 nm is 0.015 to 0.5, and

[0023] It contains nitrogen atoms, and in the measurement by ESCA (Electron Spectroscopy for Chemical Analysis), a peak from the nitrogen atoms is observed at 395 to 402 eV.

[0024] At this time, it is preferable that no peak of the anatase-type crystals is observed in the above-described X-ray diffraction measurement. It is also preferable that the specific surface area is 25 to 100 m 2 / g. It is further preferable that the absorbance A 600 at a wavelength of 600 nm is 0.1 or less. In addition, it is further preferable that in the L * a * b * color system, the L * value is 92 to 99, the a * value is -5 to 2, and the b * value is 3 to 30.

[0025] In a suitable embodiment, the surface of the particles contained in the above-mentioned powder is coated with a layer of an inorganic compound and / or an organic compound. At this time, it is preferable that it be a titanium oxide powder in which the surface of the above-mentioned particles is coated with a layer of an inorganic compound containing at least one element selected from the group consisting of aluminum, magnesium, calcium, silicon, zinc, titanium, zirconium, iron, cerium, and tin. Also at this time, it is preferable that it be a titanium oxide powder in which the surface of the above-mentioned particles is coated with a layer of an organic compound selected from the group consisting of at least one of a fatty acid or a salt thereof, an organosilicon compound, a coupling agent, and a fluorine compound. Further, at this time, it is also preferable that the L * a * b * In the color system, the L * value is 92 to 99, the a * value is -5 to 2, and the b * value is 2 to 30.

[0026] A dispersion in which the above-mentioned titanium oxide powder is dispersed in a dispersion medium is a suitable embodiment. A cosmetic, a paint, and an ink containing the above-mentioned titanium oxide powder are also suitable embodiments. Also, a toner containing the above-mentioned titanium oxide powder as an external additive is a suitable embodiment.

[0027] The above-mentioned technical problem can also be solved by providing a method for producing a titanium oxide powder, the method comprising:

[0028] an alkalization step of adding an alkali metal hydroxide to an aqueous dispersion of a titanium oxide to obtain an alkali metal titanate;

[0029] an acidification step of adding hydrochloric acid to the aqueous dispersion of the alkali metal titanate to obtain a titanium oxide containing a rutile crystal;

[0030] an impregnation step of impregnating a nitrogen-containing compound into the titanium oxide; and

[0031] a firing step of firing at 200 to 600°C.

[0032] At this time, it is preferable that the specific surface area of the titanium oxide before firing be 120 to 300 m 2 / g. Also, it is preferable that, in the impregnation step, the hydrochloric acid remaining after the acidification step be neutralized with a basic nitrogen-containing compound to impregnate the nitrogen-containing compound into the titanium oxide.

[0033] Effects of the Invention

[0034] The titanium dioxide powder of this invention is mainly composed of rutile crystals, exhibiting excellent UVA blocking effect, high safety for human use, and good color tone. Therefore, it can provide a dispersion that eliminates the bluish tint from Rayleigh scattering, possesses good transparency, and a good color tone, particularly suitable for cosmetics. Furthermore, according to the manufacturing method of this invention, such titanium dioxide powder can be easily obtained. Attached Figure Description

[0035] Figure 1 The specific surface area obtained in Example 1 is approximately 80 m². 2 X-ray diffraction pattern of / g titanium oxide powder (after calcination).

[0036] Figure 2 The specific surface area obtained in Example 1 is approximately 80 m². 2 Spectrum determined by ESCA of / g titanium oxide powder (after calcination).

[0037] Figure 3 The specific surface area obtained in Example 1 is approximately 60 m². 2 Spectrum determined by ESCA of / g titanium oxide powder (after calcination).

[0038] Figure 4 The spectrum is determined by ESCA of the titanium dioxide powder "MT-100Z" used in Comparative Example 3.

[0039] Figure 5 The specific surface area obtained in Example 1 is approximately 80 m². 2 Transmission electron microscope (TEM) image of titanium dioxide powder (after sintering) at a density of / g.

[0040] Figure 6 The specific surface area obtained in Example 1 is approximately 60 m². 2 Transmission electron microscope (TEM) image of titanium dioxide powder (after sintering) at a density of / g.

[0041] Figure 7 The specific surface area obtained in Comparative Example 1 and Comparative Example 2 is approximately 80 m². 2 A graph showing the absorbance of / g of titanium dioxide powder (after sintering).

[0042] Figure 8 This is a graph showing the light transmittance of the coating film of the emulsion preparation with a concentration of 10% by mass obtained in Comparative Example 1 and Comparative Example 3. Detailed Implementation

[0043] The peak intensity (I) of anatase crystals in the titanium oxide powder of the present invention, as determined by X-ray diffraction. A ) and the peak intensity of rutile crystals (I R The ratio of (I)A / I R ) is 0.1 or less,

[0044] the average short axis length of the contained particles is 10 to 50 nm, and the average long / short axis ratio is 1 to 3,

[0045] absorbance at a wavelength of 450 nm A 450 absorbance at a wavelength of 320 nm A 320 ratio (A 450 / A 320 ) is 0.015 to 0.5, and

[0046] contains nitrogen atoms, and in an ESCA (Electron Spectroscopy for Chemical Analysis) measurement, a peak from the nitrogen atoms is observed at 395 to 402 eV. Such a titanium oxide powder is a powder that has been first manufactured by the inventors of the present application. Details will be described below.

[0047] In the titanium oxide powder of the present application, the ratio (I A / I R ) of the peak intensity (I A ) of the anatase-type crystal to the peak intensity (I R ) of the rutile-type crystal in an X-ray diffraction measurement is 0.1 or less. When the content ratio of the anatase-type crystal is high, the photocatalyst activity becomes high, and thus, in applications in which exposure to ultraviolet light or visible light is involved, organic substances that come into contact with the titanium oxide particles are easily deteriorated. In particular, in the case where the titanium oxide is incorporated in a cosmetic, the skin is irritated, and thus, this is not preferable.

[0048] Here, the peak intensity (I R ) of the rutile-type crystal is the peak intensity (I R ) of the rutile-type titanium oxide (110 plane) near 2θ = 27.5° in an X-ray diffraction measurement. In addition, the peak intensity (I A ) of the anatase-type crystal is the peak intensity (I A ) of the anatase-type titanium oxide (101 plane) near 2θ = 25.3°. These peak intensities can be obtained using the X-ray diffraction device described in the Examples of the present specification or a device equivalent thereto, under the measurement conditions described in the Examples of the present specification or measurement conditions equivalent thereto. Each peak appearing in the X-ray diffraction measurement spectrum does not need to be an independent peak, and can be a peak of the anatase-type crystal observed as a shoulder peak of the peak of the rutile-type crystal. The peaks are separated by the analysis software attached to the device, and the intensity of each peak is calculated.

[0049] ratio (I A / IR ) is preferably 0.05 or less, and further preferably no peak of the anatase crystal is observed in the above X-ray diffraction measurement. Here, the observation of no peak of the anatase crystal means that no peak of the anatase crystal is detected when the measurement is performed under the conditions described in the Examples of the present application. In the conditions of the present Examples, the ratio (I A / I R ) is less than 0.03.

[0050] The average minor axis length of the particles contained in the titanium oxide powder of the present application is 10 to 50 nm. By making the average minor axis length 10 nm or more, the shielding effect of UVA (320 to 400 nm) can be improved. In the case where the average minor axis length is less than 10 nm, although the shielding effect of UVB (280 to 320 nm) can be improved, the shielding effect of UVA is reduced. Although the shielding of UVB, which is feared to cause inflammation of the skin, is important, the shielding of UVA, which causes the deposition of melanin and makes the skin black, is also important, and particularly from the viewpoint of cosmetics, the shielding of UVA is extremely important. The average minor axis length is preferably 12 nm or more, and more preferably 14 nm or more. On the other hand, by making the average minor axis length 50 nm or less, the transparency of the coating film containing the titanium oxide can be improved. The average minor axis length is preferably 40 nm or less, and more preferably 30 nm or less. The average minor axis length and the average major axis length are obtained by taking a transmission electron microscope (TEM) photograph, and image processing the particles.

[0051] In addition, the average length-to-minor axis ratio (average major axis length / average minor axis length) of the particles contained in the titanium oxide powder of the present application is 1 to 3. Generally, inorganic particles in a needle shape are feared to irritate the lungs or the skin, and thus there is a concern about the safety to the human body. By making the average length-to-minor axis ratio 3 or less, the safety to the human body can be improved. In addition, by reducing the average length-to-minor axis ratio, the powdery peculiar feeling of stickiness when the cosmetic containing the titanium oxide is applied to the skin can be greatly reduced, and thus the feeling of use is also excellent. The average length-to-minor axis ratio is more preferably 2.5 or less, and further preferably 2 or less.

[0052] The absorbance A450 of the titanium oxide powder of the present application at a wavelength of 450 nm 450 The absorbance A320 at a wavelength of 320 nm 320 The ratio (A 450 / A 320 ) is 0.015 to 0.5. By making the ratio (A 450 / A 320 ) 0.015 or more, blue light can be absorbed, and the blue based on Rayleigh scattering can be effectively eliminated. Furthermore, a color tone close to the skin color can be obtained, and thus the transparency when applied to the skin can be improved. The ratio (A 450 / A 320The preferred value is 0.025 or higher. On the other hand, the ratio of (A) to... 450 / A 320 When the concentration exceeds 0.5, it will cause significant coloring and become difficult to use in cosmetics. Compared to (A... 450 / A 320 The absorbance is preferably 0.4 or less, more preferably 0.3 or less. The absorbance of the titanium dioxide powder is obtained by compressing the powder into a molded product as a sample and measuring it using a spectrophotometer with diffusion-reflectance method.

[0053] The titanium dioxide powder of the present invention contains nitrogen atoms, and in ESCA (Electron Spectroscopy for Chemical Analysis) measurements, peaks from these nitrogen atoms are observed in the range of 395–402 eV. In ESCA measurements, the binding energy peak of Ti–N is considered to appear around 397 eV, and the binding energy peaks of Ti–N–O and Ti–O–N are considered to appear around 400 eV. The presence or absence of these peaks can be determined by observing them in ESCA measurements under the conditions described in the embodiments of this application. Furthermore, the presence of nitrogen atoms can be determined by observing any of these peaks. It should be noted that, in ESCA measurements, peaks from scandium atoms are known to appear as doublets (width 4.3 eV) at 406 eV and 401.7 eV. Of these, the 401.7 eV peak overlaps with the 395–402 eV range specified in the present invention, but this peak is not considered. Additionally, scandium atoms are generally not incorporated into the titanium dioxide powder of the present invention.

[0054] like Figure 2 As shown, in Example 1, the specific surface area obtained by calcining at 380°C after neutralization with ammonia is approximately 80 m². 2 In titanium dioxide powder of / g, a peak near 400eV exists on the surface of the particles, and a peak near 397eV exists inside the particles. On the other hand, as Figure 3 As shown, in Example 1, the specific surface area obtained by calcining at 480°C after neutralization with ammonia is approximately 60 m². 2 In titanium dioxide powder of / g, a peak near 400eV exists on the surface of the particles, but a peak near 397eV is absent inside the particles. Therefore, when the particles are increased in size during high-temperature sintering, there is a possibility that the Ti-N bonds temporarily formed inside the particles may disappear. On the other hand, as... Figure 4 As shown, in Comparative Example 3, no peaks were observed in the commercially available titanium dioxide powder that was neither neutralized with ammonia nor calcined. It should be noted that, as shown in Comparative Example 2, the titanium dioxide particles obtained by calcination without ammonia neutralization had a specific surface area of ​​approximately 60 m² compared to Example 1. 2Similarly, the titanium dioxide powder of / g exhibited a peak around 400eV on the surface of the particles, but no peak around 397eV inside the particles. It is believed that this peak around 400eV is generated by nitrogen atoms from atmospheric nitrogen molecules combining with the surface of the titanium dioxide particles during atmospheric firing. However, unlike the titanium dioxide powders of Examples 1-4, the titanium dioxide powder of Comparative Example 2 did not adequately absorb light at 450nm, and the absorbance A at a wavelength of 450nm was [not specified]. 450 Absorbance A at a wavelength of 320 nm 320 The ratio (A) 450 / A 320 The value is below 0.015. Given the above, it is speculated that by neutralizing with ammonia and then calcining at high temperature, even if the Ti-N bonds temporarily formed inside the particles disappear, a structure that absorbs light at 450 nm will remain. Therefore, a peak from nitrogen atoms was observed in the range of 395–402 eV, and this resulted in a higher value than (A). 450 / A 320 With a concentration of 0.015 to 0.5, titanium dioxide powder with a good color tone can be obtained.

[0055] Furthermore, the absorbance A of the titanium dioxide powder of the present invention at a wavelength of 600 nm... 600 Preferably, it is below 0.1. This is achieved by making the absorbance A... 600 A value below 0.1 effectively suppresses the absorption of red light. When both blue and red light are absorbed, the hue becomes darker, making it less desirable for cosmetic use. Absorbance A 600 More preferably, it is 0.07 or less, and even more preferably, it is 0.05 or less.

[0056] The titanium dioxide powder of the present invention is preferably in L * a * b * In the color system, L * The value is 92-99, a * Values ​​range from -5 to 2, b * The value is between 3 and 30. By making L... * A value of 92 or higher can produce powders with high whiteness and no dullness. * The value is more preferably 93 or higher, and even more preferably 95 or higher. Furthermore, by making a... * A value below 2 can suppress redness. * The value is more preferably 0 or less, and even more preferably -1 or less. Furthermore, by making b... * A value of 3 or higher can effectively eliminate blue. * The value is more preferably 4 or higher, and even more preferably 5 or higher. On the other hand, b * When the value exceeds 30, the yellow color may sometimes be too concentrated. *The value is more preferably 20 or less, and further preferably 15 or less.

[0057] In addition, the titanium oxide powder of the present application preferably has an iron content of 300 ppm or less. The iron content (ppm) is the mass of iron element with respect to the mass of the powder. By having an iron content of 300 ppm or less, a dispersion, particularly a cosmetic, having excellent transparency without a dull feeling can be obtained. The iron content is further preferably 200 ppm or less, and further preferably 150 ppm or less. When the iron content is too high, the titanium oxide particles can aggregate, and there is a risk that the transparency will deteriorate. Note that the titanium oxide powders obtained in the examples and comparative examples are powders that do not particularly contain iron elements.

[0058] The specific surface area of the titanium oxide powder of the present application is preferably 25 to 100 m 2 / g. By having a specific surface area of 25 m 2 / g or more, whitening can be reduced, and a dispersion, particularly a cosmetic, having excellent transparency can be obtained. The specific surface area is more preferably 40 m 2 / g or more, and further preferably 50 m 2 / g or more. On the other hand, by having a specific surface area of 100 m 2 / g or less, UVA can be effectively shielded, and a dispersion, particularly a cosmetic, that suppresses the production of melanin due to sunlight can be obtained. The specific surface area is more preferably 90 m 2 / g or less.

[0059] The manufacturing method of the titanium oxide powder of the present application will be described below. Suitable manufacturing methods include: an alkalization step of adding an alkali metal hydroxide to an aqueous dispersion of hydrous titanium oxide (TiO2-nH2O) to obtain an alkali metal titanate; an acidification step of adding hydrochloric acid to the aqueous dispersion of the alkali metal titanate to obtain titanium oxide (TiO2) containing rutile crystals; an impregnation step of impregnating a nitrogen-containing compound into the titanium oxide; and a firing step of firing at 200 to 600°C.

[0060] In the above-mentioned alkalization step, an alkali metal hydroxide is added to an aqueous dispersion of hydrous titanium oxide (titanium dioxide hydrate: TiO2-nH2O) to obtain an alkali metal titanate. The manufacturing method of the hydrous titanium oxide used at this time is not particularly limited, and a hydrous titanium oxide manufactured by hydrolyzing an aqueous solution of titanyl sulfate (TiOSO4) by heating, or the like, can be used. The hydrous titanium oxide thus obtained generally contains anatase crystals.

[0061] As the alkali metal hydroxide to be added to the above aqueous dispersion of titanium oxide, sodium hydroxide, potassium hydroxide and lithium hydroxide can be mentioned, with sodium hydroxide and potassium hydroxide being preferred, and sodium hydroxide being particularly preferred. The number of moles of the alkali metal hydroxide added at this time is preferably 2 to 20 times the number of moles of titanium element in the aqueous titanium oxide. The heating temperature at this time is preferably 60 to 120°C. Thus, an aqueous dispersion of alkali metal titanate can be obtained. As the alkali metal titanate, sodium titanate (Na2OTi3), potassium titanate and lithium titanate can be mentioned.

[0062] In the acidification step after the alkalization step, hydrochloric acid is added to the above aqueous dispersion of alkali metal titanate to obtain titanium oxide (TiO2) containing rutile-type crystals. By adding hydrochloric acid to make the aqueous dispersion acidic, an aqueous dispersion in which titanium oxide particles containing rutile-type crystals are dispersed can be obtained. The amount of hydrochloric acid to be added is an amount that can neutralize the excess alkali in the aqueous dispersion and make the aqueous dispersion acidic. Further, it is preferable to heat after adding the hydrochloric acid to perform ripening, and by adjusting the conditions thereof, the particles can be grown. A suitable ripening temperature is 40 to 110°C. More preferably, it is 60°C or higher. Further, more preferably, it is 105°C or lower. A suitable ripening time is 2 minutes to 24 hours. More preferably, it is 5 minutes or more. Further, more preferably, it is 10 hours or less.

[0063] In the impregnation step after the acidification step, a nitrogen-containing compound is impregnated into the obtained titanium oxide. Either the nitrogen-containing compound can be added to the aqueous dispersion of titanium oxide obtained in the acidification step and impregnated, or the aqueous dispersion can be dried and then the nitrogen-containing compound can be impregnated. The nitrogen-containing compound used here is not particularly limited, and ammonia, ammonium bicarbonate, amine, urea, etc. can be used.

[0064] In the impregnation step, it is preferable to neutralize the hydrochloric acid remaining after the acidification step with a basic nitrogen-containing compound and impregnate the nitrogen-containing compound into the titanium oxide. By doing so, in the aqueous dispersion containing titanium oxide particles, the nitrogen-containing compound can be uniformly impregnated while performing the neutralization operation. As the basic nitrogen-containing compound used at this time, ammonia, ammonium bicarbonate, amine, etc. can be used. The addition of aqueous ammonia is particularly preferred because it is simple and inexpensive. After the neutralization operation, the titanium oxide particles are dried by removing the water by heating. A suitable drying temperature is 70°C or higher and less than 200°C. After drying, the titanium oxide powder (before firing) can be obtained by pulverizing and sieving as needed.

[0065] In addition, the residual hydrochloric acid after the acidification step can be neutralized by using a base other than the nitrogen-containing compound. As such a base, sodium hydroxide, potassium hydroxide, and the like can be exemplified. After the neutralization operation, the titanium oxide particles are dried by heating, whereby water is removed. The suitable drying temperature is 70°C or higher and lower than 200°C. After drying, the titanium oxide powder (before firing) can be obtained by pulverizing and sieving as necessary. The titanium oxide powder (before firing) is impregnated with a solution of the basic nitrogen-containing compound, preferably an aqueous solution, and then subjected to a firing step.

[0066] In the firing step, the titanium oxide powder is fired at 200 to 600°C. Thereby, the short axis length of the titanium oxide particles can be elongated, and the ratio of the long axis to the short axis can be reduced. The firing temperature is preferably 250°C or higher, and more preferably 300°C or higher. In addition, the firing temperature is preferably 550°C or lower, and more preferably 500°C or lower. The atmosphere during firing is not particularly limited, and the powder can be fired in an atmospheric atmosphere. In this case, a nitrogen atom from a nitrogen molecule in the atmosphere can sometimes be combined with the surface of the titanium oxide particles. After firing, the titanium oxide powder (after firing) can be obtained by pulverizing and sieving as necessary.

[0067] The titanium oxide powder of the present application can be directly used for various applications, and is preferably surface-coated. That is, a suitable embodiment of the present application is a titanium oxide powder in which the surface of the titanium oxide particles contained in the above powder is coated with a layer of an inorganic compound and / or an organic compound.

[0068] As the inorganic compound for coating the titanium oxide particles, a compound containing at least one element selected from the group consisting of aluminum, magnesium, calcium, silicon, zinc, titanium, zirconium, iron, cerium, and tin is preferable. By using a compound containing these elements for coating, the durability and dispersion stability of the titanium oxide particles can be improved. A particularly suitable compound is an aluminum compound, and coating in the form of aluminum hydroxide is preferable, whereby the dispersion stability can be improved, and the photocatalyst activity peculiar to titanium oxide can be suppressed. As a method for coating with aluminum hydroxide, a method in which a salt such as aluminum chloride is added to a slurry containing titanium oxide particles, and the aluminum hydroxide is precipitated on the surface of the titanium oxide particles by hydrolysis can be exemplified. The suitable content of aluminum in the titanium oxide powder is 2 to 30 parts by mass with respect to 100 parts by mass of TiO2 as Al2O3.

[0069] As the organic compound to coat the titanium oxide particles, at least one selected from the group consisting of a fatty acid or a salt thereof, a silicone-based compound, a coupling agent, and a fluorine compound can be exemplified. Among these, a fatty acid or a salt thereof is preferred, whereby lipophilicity can be imparted to the surface of the titanium oxide particles, and dispersion in an oil phase becomes easy. In particular, when used in cosmetics and the like, the cosmetics applied to the skin are not easily taken away by sweat or rain, and durability is improved. As the fatty acid used here, a higher fatty acid having 12 to 30 carbon atoms is preferably used, and an aluminum salt is preferably used as the salt thereof. As a method of coating with the fatty acid or the salt thereof, a method of adding an alkali metal fatty acid salt to a slurry containing titanium oxide particles, and then precipitating free fatty acid onto the surface of the titanium oxide particles by adding a strong acid such as sulfuric acid can be exemplified. As a suitable content of the fatty acid or the salt thereof in the titanium oxide powder, 2 to 50 parts by mass per 100 parts by mass of TiO2 is preferable. This content is an amount converted into free fatty acid.

[0070] The layer of the inorganic compound coating the surface of the titanium oxide particles is not necessarily a uniform layer, and can be a layer coating only a part of the surface. The same is true for the layer of the organic compound. The layer of the inorganic compound and the layer of the organic compound can be formed as different layers, or both the inorganic compound and the organic compound can be contained in one layer. In a suitable embodiment, the surface of the titanium oxide particles is coated with a layer containing aluminum hydroxide and a higher fatty acid having 12 to 30 carbon atoms or an aluminum salt thereof.

[0071] In the case of the titanium oxide powder in which the surface of the titanium oxide particles is coated with a layer of an inorganic compound and / or an organic compound, in L * a * b * In the color system, L * is preferably 92 to 99, a * is -5 to 2, and b * is 2 to 30. By coating the surface, the b * value decreases compared to the uncoated powder, and therefore, in the coated titanium oxide powder, the lower limit value of the b * value is lowered to 2. As a more suitable range, L * , a * , and b * all have the same values as the uncoated titanium oxide powder.

[0072] A dispersion obtained by dispersing the thus obtained titanium oxide powder of the present application in a dispersion medium is a suitable embodiment. The dispersion medium at this time can be water, or an organic solvent. In addition, it can be a mixed solvent of water and an organic solvent, or an emulsion formed from water and an organic solvent.

[0073] Suitable uses are cosmetics, paints, inks, toners, and the like, which contain the titanium oxide powder of the present application.

[0074] Particularly suitable uses among these are cosmetics, preferably cosmetics having an ultraviolet-shielding effect, and particularly cosmetics capable of inhibiting the deposition of melanin. In the cosmetics of the present application, inorganic pigments and organic pigments other than the titanium oxide powder of the present application can be incorporated. As inorganic pigments that can be used, titanium oxide, zinc oxide, red iron oxide, yellow iron oxide, black iron oxide, ultramarine, Prussian blue, cerium oxide, talc, white mica, synthetic mica, phlogopite, biotite, synthetic fluorphlogopite, mica titanium, mica-like iron oxide, sericite, zeolite, kaolin, bentonite, clay, silicic acid, silicic anhydride, magnesium silicate, aluminum silicate, calcium silicate, barium sulfate, magnesium sulfate, calcium sulfate, calcium carbonate, magnesium carbonate, boron nitride, bismuth oxychloride, aluminum oxide, zirconium oxide, magnesium oxide, chromium oxide, malachite, carbon black, hydroxyapatite, and complexes thereof can be used. In addition, as organic pigments that can be used, silicone powder, polyurethane powder, cellulose powder, nylon powder, silk powder, polymethyl methacrylate (PMMA) powder, starch, polyethylene powder, polystyrene powder, tar pigment, natural pigment, and complexes thereof can be used.

[0075] In the cosmetics of the present application, other components can be incorporated as necessary. For example, pH adjustors, humectants, tackifiers, surfactants, dispersion stabilizers, preservatives, antioxidants, metal masking agents, astringents, anti-inflammatory agents, ultraviolet absorbers, perfumes, and the like can be appropriately incorporated.

[0076] As the form of the cosmetics of the present application, emulsions, lotions, oils, creams, pastes, and the like can be exemplified. In addition, as specific uses thereof, sunscreen cosmetics, makeup bases, foundations, concealers, control colors, lipsticks, lip balms, eye shadows, eye liners, mascaras, blushes, nail polishes, and the like can be exemplified.

[0077] In the case where the titanium oxide powder of the present application is used in paints and inks, the titanium oxide particles can be dispersed in a solution in which a base polymer is dissolved, or the titanium oxide particles can be dispersed in an aqueous emulsion in which particles of a base polymer are dispersed. In addition, pigments, matting agents, surfactants, dispersion stabilizers, leveling agents, tackifiers, antioxidants, ultraviolet absorbers, and the like, which are generally added to paints and inks, can be incorporated. In addition, in paints in which particulate titanium oxide is incorporated, there are paints having a so-called "flip-flop" effect in which the color tone changes depending on the viewing angle, and by using the titanium oxide of the present application, a "flip-flop" paint film having less bluing can be formed.

[0078] In the case where the titanium oxide powder of the present application is used as an external agent for toner, it is used after being mixed with toner particles containing a pigment. By using the fine particulate titanium oxide, toner having excellent stability of charging performance in various environments can be provided. At this time, various additives conventionally added can be incorporated in the toner.

[0079] Examples

[0080] The present application is more specifically described below by way of examples. The analysis method and evaluation method in the examples are based on the following methods.

[0081] (1) X-ray Diffraction Measurement

[0082] The titanium oxide powder which was pressed flat on a sample holder with a glass plate was measured using an X-ray diffractometer (manufactured by Philips). The measurement conditions were as follows.

[0083] • Diffractometer system: XPERT-PRO

[0084] • Ray source: Cu Kα

[0085] • Scanning step: 2θ = 0.008°

[0086] • Voltage: 45 kV

[0087] • Current: 20 mA

[0088] • Measurement range: 2θ = 5 to 100°

[0089] • Analysis accessory software: HighScore Plus

[0090] The peak intensity (I R ) of the rutile-type titanium oxide (110 plane) around 2θ = 27.5° and the peak intensity (I A ) of the anatase-type titanium oxide (101 plane) around 2θ = 25.3° were measured, and the ratio (I A / I R ) thereof was calculated. At this time, the peak search function of the above accessory software was used to perform peak search under the following conditions. In the case where peak search was performed under the above conditions, the ratio (I A / I R ) in the detection limit of the peak of the anatase-type crystal was 0.03. Therefore, the ratio (I A / I R ) when the peak of the anatase-type crystal was not detected was lower than 0.03.

[0091] • Minimum significance: 0.50

[0092] • Minimum peak tip: 0.10°

[0093] • Maximum peak tip: 1.00°

[0094] • Peak base width: 2.00°

[0095] • Method: Minimum value of 2nd differential

[0096] (2) ESCA measurement

[0097] ESCA (Electron Spectroscopy for Chemical Analysis) measurement was performed using an X-ray photoelectron spectrometer ("ESCA 3400" manufactured by Shimadzu Corporation). The powder of the sample was pressed into a thin film and fixed to a carbon tape, and then measurement was performed. Surface etching by argon sputtering for 15 seconds was repeated, and thereby the distribution of nitrogen atoms in the depth direction of the sample was measured. The binding energy of Cls at 284.6 eV was used for correction. The measurement conditions and etching conditions are as follows.

[0098] (Measurement conditions)

[0099] • X-ray source: Mg-Ka line

[0100] • Filament voltage-current: 12 kV-15 mA

[0101] • Vacuum degree: less than 1.0 x 10 －6 Pa

[0102] • Measurement range: 385-415 eV

[0103] • Measurement step: 0.1 eV

[0104] • Accumulation number: 30 times

[0105] (Argon etching conditions)

[0106] • Filament voltage-current: 2 kV-20 mA

[0107] • Ion source: argon gas

[0108] • Vacuum degree during argon etching: 1.0 x 10 －4 Pa

[0109] • Etching time: 15 seconds / time

[0110] (3) Shape and size of particles

[0111] Transmission electron microscopy (TEM) images were taken, and the major axis length (nm) and minor axis length (nm) of the particles were determined through image processing. The major-minor axis ratio was calculated as (major axis length / minor axis length). More than 200 particles were measured to obtain the average minor axis length (nm) and average major-minor axis ratio.

[0112] (4) Specific surface area

[0113] The specific surface area was determined using a fully automated specific surface area measuring device (Macsorb HM model-1208 manufactured by MOUNTECH Co., Ltd.) via the BET method. During the measurement, the surface area was degassed at 150°C for 20 minutes under a nitrogen atmosphere before measurement.

[0114] (5)Powder color

[0115] A 43φ aluminum ring (RIGAKU Co., Ltd., dimensions: outer diameter 43mm, inner diameter 40mm, height 5mm) was placed on the packaging paper for the powder sample. Titanium oxide powder was filled into the ring and smoothed. The ring was then molded using a tablet forming compressor (BRE-32, Maekawa Testing Machines Co., Ltd.), applying 15MPa pressure for 30 seconds to obtain tablets with a thickness of 2.5–3.0mm, which were used as samples for testing. The color of these samples was measured using a Konica Minolta CR-400 colorimeter. After white calibration of the colorimeter, the color difference at L was measured. * a * b * L in the color system * value, a * value and b * value.

[0116] (6) Absorbance

[0117] The tablets obtained in the same manner as those described in "(5) Powder Color" were used as samples, and their absorbance was obtained by diffusion-reflectance method using a spectrophotometer with an integrating sphere ("U-4100" manufactured by Hitachi High Tech Co., Ltd.). The measurement conditions are as follows. The measurement was performed after standard correction using a barium sulfate standard white plate.

[0118] • Scanning speed: 300nm / minute

[0119] • Sampling interval: 2nm

[0120] • Measurement wavelength: 250–700 nm

[0121] The absorbance A at a wavelength of 450 nm 450 and absorbance A at a wavelength of 320 nm 320 Calculate the absorbance ratio (A)450 / A 320 )。

[0122] (7) Color difference of coated film

[0123] A PET film on which a coated film was formed on a part of the surface was placed on a standard color of skin color, BIO SKIN (BEAULAX Co., Ltd., # BioColor BSC), and the color difference was measured from the coated film side using a color difference meter ("CR-400" manufactured by Konica Minolta Co., Ltd.). After white correction of the color difference meter, the color difference was measured for the uncoated part (blank) and the coated part on the PET film in L * a * b * L * value, a * value and b * value in the color system. Using the average value obtained by measuring the coated part twice, the color difference ΔE between the blank and the coated part was calculated by the following calculation formula. The smaller the value of ΔE, the less the deviation from the skin color, indicating better matching with the skin.

[0124]

[0125] Here, L * 1, a * 1 and b * 1 represent the L * value, a * value and b * value of the blank, and L * 2, a * 2 and b * 2 represent the L * value, a * value and b * value of the coated part.

[0126] (8) Sensory evaluation of emulsified preparation (use feeling, whitening, blueness, transparency)

[0127] A test panel of 10 people applied the emulsified preparation to the skin of the forearm under daylight and evaluated the use feeling, and evaluated the whitening, blueness and transparency by visual observation while changing the observation angle. For the evaluation of blueness, in particular, blueness in which the blue part of the veins could be seen was observed.

[0128] Example 1

[0129] Aqueous solutions of titanium oxysulfate (TiOSO4) were heated to 100°C to hydrolyze it, precipitating hydrated titanium dioxide (TiO2·nH2O) to obtain a slurry. The slurry was filtered, and the resulting filter cake was washed with water to obtain 35 kg of hydrated titanium dioxide filter cake (equivalent to 10 kg in TiO2 form). The obtained hydrated titanium dioxide contained anatase crystals. While adding 70 kg of a 48% by mass sodium hydroxide aqueous solution to the filter cake, the mixture was stirred and heated at 95–105°C for 2 hours to obtain a sodium titanate (Na2O7Ti3) slurry. This slurry was filtered, and the resulting filter cake was thoroughly washed with water to obtain a sodium titanate filter cake. Water was added to the obtained filter cake to obtain a slurry containing 170 g / L of sodium titanate in TiO2 form.

[0130] 14.0 kg of 35% hydrochloric acid was added to the above-mentioned slurry containing sodium titanate and heated to 80°C for 10 minutes. The slurry was then diluted with water to obtain a slurry containing 70 g / L of titanium oxide (based on TiO2). The obtained titanium oxide contained rutile crystals. The titanium oxide slurry was heated to 80°C, adjusted to pH 7.0 with ammonia, and then aged for 30 minutes. After aging, the pH was adjusted to 7.0 again with ammonia or hydrochloric acid. The obtained slurry was filtered and washed to obtain a titanium oxide filter cake. The filter cake was dried at 110°C, pulverized using an impact mill, and sieved through a 0.3 mm sieve to obtain titanium oxide powder (before calcination). The titanium oxide powder had an average minor axis length of 6 nm and an average major-to-minor axis ratio of 3.5. Furthermore, the specific surface area, determined by the BET method, was 204 m². 2 / g, L measured by a colorimeter * The value is 97.99, a * The value is -0.53, b * The value is 2.41. The above evaluation results are summarized in Table 1.

[0131] The obtained titanium dioxide powder (before calcination) was placed in a covered crucible that was not airtight, and then heated in an atmospheric atmosphere using a box-type electric furnace ("KBF828N1" manufactured by Koyo Thermal Systems Co., Ltd.) to achieve a specific surface area of ​​approximately 80 m². 2 The sample was fired at 380℃ for 120 minutes using a method of / g. The resulting fired product was then pulverized using an impact crusher and sieved through a 0.3mm sieve, yielding a specific surface area of ​​82.0 m². 2 / g of titanium dioxide powder (after calcination). Additionally, in the same operation, the specific surface area is made to be approximately 60m². 2 By changing the firing temperature to 480℃ using the / g method, a specific surface area of ​​60.3m² was also obtained. 2 / g of titanium dioxide powder (after calcination).

[0132] The thus obtained titanium oxide powder (after firing) was analyzed and evaluated in accordance with the above-described method. The X-ray diffraction pattern of the titanium oxide powder (after firing) having a specific surface area of about 80 m 2 / g is shown in Fig. 2. Figure 1 No peak of anatase-type crystal was detected, and the ratio (I A / I R ) of the peak intensity (I A ) of the anatase-type crystal to the peak intensity (I R ) of the rutile-type crystal was lower than 0.03. Further, in the X-ray diffraction measurement of the titanium oxide powder (after firing) having a specific surface area of about 60 m 2 / g, no peak of anatase-type crystal was detected. Furthermore, in all of the titanium oxide powders (after firing) obtained in Examples 2 to 4 and Comparative Examples 1 and 2 described later, no peak of anatase-type crystal was detected.

[0133] The ESCA measurement spectrum of the titanium oxide powder (after firing) having a specific surface area of about 80 m 2 / g is shown in Fig. 4. Figure 2 Before etching (Ar-0 sec), a peak was observed near the binding energy of 400 eV, and after etching for 15 sec and 30 sec (Ar-15 sec, Ar-30 sec), a larger peak was observed near the binding energy of 397 eV and a smaller peak was observed near the binding energy of 400 eV. All of the peaks were peaks from nitrogen atoms.

[0134] Further, the ESCA measurement spectrum of the titanium oxide powder (after firing) having a specific surface area of about 60 m 2 / g is shown in Fig. 5. Figure 3 Before etching (Ar-0 sec), a peak from nitrogen atoms was observed near the binding energy of 400 eV, but after etching for 15 sec and 30 sec (Ar-15 sec, Ar-30 sec), no peak was observed in the range of the binding energy of 395 to 402 eV.

[0135] The TEM photograph of the titanium oxide powder (after firing) having a specific surface area of about 80 m 2 / g is shown in Fig. 6. Figure 5 Based on the TEM photograph, image processing was performed, and the average short axis length was calculated to be 12.7 nm and the average ratio of long axis to short axis was calculated to be 1.60. Further, the TEM photograph of the titanium oxide powder (after firing) having a specific surface area of about 60 m 2 / g is shown in Fig. 7. Figure 6 Based on the TEM photograph, image processing was performed, and the average short axis length was calculated to be 22.4 nm and the average ratio of long axis to short axis was calculated to be 1.54.

[0136] The color difference meter measurement results of the titanium oxide powder (after firing) having a specific surface area of about 80 m 2L of the titanium oxide powder (after firing) of 96.58, a * value of 96.04, a * value of -1.66, b * value of 7.93. In addition, the specific surface area was about 60 m 2 L of the titanium oxide powder (after firing) of 96.58, a * value of 96.58, a * value of -1.37, b * value of 7.58.

[0137] In addition, the specific surface area measured by the spectrophotometer was about 80 m 2 A graph of the absorbance of the titanium oxide powder (after firing) of the specific surface area of about 80 m 2 A graph of the absorbance of the titanium oxide powder (after firing) of the specific surface area of about 80 m Figure 7 The titanium oxide powder of Example 1 had a characteristic absorption around 450 nm, but in Comparative Example 2 in which neutralization was not performed using ammonia, there was no absorption around 450 nm.

[0138] The specific surface area was about 80 m 2 The absorbance at 320 nm was 1.041, the absorbance at 450 nm was 0.088, and the absorbance at 600 nm was 0.014. Thus, the ratio (A 450 / A 320 ) was 0.085. In addition, the specific surface area was about 60 m 2 The absorbance at 320 nm was 1.034, the absorbance at 450 nm was 0.081, and the absorbance at 600 nm was 0.007. Thus, the ratio (A 450 / A 320 ) was 0.078. With respect to the evaluation results above, the titanium oxide powder (after firing) of the specific surface area of about 80 m 2 / g is summarized in Table 2, and the titanium oxide powder (after firing) of the specific surface area of about 60 m 2 / g is summarized in Table 3.

[0139] (Preparation of varnish)

[0140] A varnish 3500 g was prepared by uniformly mixing the following materials. At this time, the solid content concentration of nitrocellulose (NC) was 10 mass %.

[0141] • Nitrocellulose (H1 / 2): 500 g

[0142] (KISHIDA Chemical Corporation, solid content concentration about 70 mass %)

[0143] • n-butyl acetate: 1050 g

[0144] • ethyl acetate: 700 g

[0145] • ethylene glycol mono-n-butyl ether: 350 g

[0146] • toluene: 900 g

[0147] (Preparation of nitrocellulose paint)

[0148] The varnish 40 g obtained as above, titanium oxide powder (after firing) 1.714 g having a specific surface area of about 80 m 2 / g, and zirconium dioxide beads (φ0.5 mm, manufactured by SHINMARU ENTERPRISES Co., Ltd.) 130 g as a dispersion medium were put into a 100 mL bottle (manufactured by NIKKO HANSEN Co., Ltd.: J bottle round mouth) and dispersed for 90 minutes using a paint conditioner (manufactured by RED DEVIL Co., "1400-OH") after which the zirconium dioxide beads were separated, and a paint was prepared. In the paint thus obtained, 30 mass% of titanium oxide was contained with respect to the entire solid components.

[0149] (Formation and evaluation of nitrocellulose coating film)

[0150] The paint thus obtained was applied to a PET film (manufactured by PANAC Co., Ltd.: LUMIRROR 100T60) using an automatic rod applicator equipped with a wire rod (No. 22), and dried at room temperature for 24 hours, and a coating film was formed. The coating film thus formed was evaluated for color difference ΔE from BIO SKIN by the above method. As a result, ΔE was 9.6. Further, a paint and a coating film were prepared in the same manner using titanium oxide powder having a specific surface area of about 60 m 2 / g, and the evaluation was performed, and ΔE was 10.2.

[0151] (Surface treatment)

[0152] To titanium oxide powder (after firing) having a specific surface area of about 80 m 2 / g or a specific surface area of about 60 m 2 / g, water was added to obtain a titanium oxide slurry of 70 g / L in terms of TiO2. The titanium oxide slurry was warmed to 85°C, and a 10 mass% aqueous solution of polyaluminum chloride (PAC: [Al3(OH) n Cl 6－n ] m ) was added, and allowed to mature for 10 minutes. As to the amount of PAC to be added, 6 parts by mass in terms of Al2O3 was added with respect to 100 parts by mass of titanium oxide powder having a specific surface area of about 80 m 2 / g, and 6 parts by mass in terms of Al2O3 was added with respect to 100 parts by mass of titanium oxide powder having a specific surface area of about 60 m2 / g of titanium oxide powder 100 parts by mass, in an amount of 4 parts by mass in terms of Al2O3. After adjusting the pH to 6.0 using a 48 mass% aqueous sodium hydroxide solution and maturing for 30 minutes, sodium stearate was added. As to the amount of sodium stearate to be added, relative to the specific surface area of about 80 m 2 / g of titanium oxide powder 100 parts by mass, in an amount of 7 parts by mass, relative to the specific surface area of about 60 m 2 / g of titanium oxide powder 100 parts by mass, in an amount of 5 parts by mass. After adding sodium stearate and maturing for 60 minutes, the pH was adjusted to 6.0 using a 50 mass% sulfuric acid, and after further maturing for 30 minutes, the obtained slurry was filtered, washed with water, and a filter cake of titanium oxide coated with layers of aluminum hydroxide and stearic acid (or aluminum stearate) was obtained. After drying the filter cake at 110°C, the same was pulverized using an impact-type pulverizer and sieved with a 0.3 mm sieve, and a surface-coated titanium oxide powder was obtained. The titanium oxide particles in the obtained powder were coated with layers of aluminum hydroxide and stearic acid (or aluminum stearate). The average minor axis length and average ratio of major axis to minor axis of the particles contained in the surface-treated titanium oxide powder were substantially the same as those of the titanium oxide powder before surface treatment.

[0153] Using the thus obtained surface-coated titanium oxide powder having a specific surface area of about 80 m 2 / g and a specific surface area of about 60 m 2 / g of titanium oxide powder, an emulsified preparation having a titanium oxide concentration of 25 mass% was prepared. In addition, using surface-coated titanium oxide powder having a specific surface area of about 60 m 2 / g of titanium oxide powder, an emulsified preparation having a titanium oxide concentration of 10 mass% was prepared. All of the emulsified preparations were assumed to be cosmetics.

[0154] (Emulsified preparation (concentration 25 mass%))

[0155] An oil phase raw material of 30.87 g shown below, surface-coated titanium oxide powder having a specific surface area of about 80 m 2Titanium oxide powder 22.05 g having a specific surface area of 50 m2 / g and zirconium dioxide beads (manufactured by SHINMARU ENTERPRISES Co., Ltd.) having a diameter of 0.5 mm as a dispersion medium 130 g were put in a 100 mL bottle (manufactured by NIKKO HANSEN Co., Ltd.: J bottle round mouth), and dispersed for 5 hours using a paint conditioner (manufactured by RED DEVIL Co., 1400-OH). After the zirconium dioxide beads were separated, an oil phase dispersion was prepared. The oil phase dispersion 37.80 g was put in a 100 mL polypropylene cup, and a mixture of the water phase raw materials shown below 25.2 g was added while stirring at a stirring speed of 3000 rpm using a high-speed emulsifying / dispersing machine (manufactured by PRIMIX Co., "T.K. ROBOMIX"). The stirring was continued for 5 minutes at 3000 rpm, and an emulsion preparation was prepared.

[0156] (Oil phase raw materials)

[0157] • Cyclopentasiloxane 21.07 g: "KF-995" manufactured by SHIN-ETXU CHEMICAL CO., LTD.

[0158] • Liquid paraffin 4.9 g: "MORESCO WHITE P-70" manufactured by MORI SUGI CO., LTD.

[0159] • PEG-9 dimethicone 4.9 g: "KF-6019" manufactured by SHIN-ETXU CHEMICAL CO., LTD.

[0160] (Water phase raw materials)

[0161] • Ion exchange water 17.53 g

[0162] • 1,3-Butylene glycol 7.67 g

[0163] The emulsion preparation thus obtained was applied to a PET film (manufactured by PANAC Co., Ltd.: LUMIRROR 100T60) using an automatic bar coater equipped with a wire bar (No. 6), and left to stand at room temperature for 24 hours to dry, and a coating film was formed. The color difference ΔE of the coating film thus formed was evaluated by the above method. As a result, ΔE was 4.8. In addition, the specific surface area of the surface-coated titanium oxide powder was about 60 m 2 The emulsion preparation having a concentration of 25 mass% was prepared in the same manner using titanium oxide powder having a specific surface area of 50 m2 / g, and evaluated in the same manner, and ΔE was 6.4.

[0164] (Evaluation of an emulsion preparation having a concentration of 10 mass%)

[0165] The oil phase raw materials shown below 38.50 g and zirconium dioxide beads (manufactured by SHINMARU ENTERPRISES Co., Ltd.) having a diameter of 0.5 mm as a dispersion medium 130 g were put in a 100 mL bottle (manufactured by NIKKO HANSEN Co., Ltd.: J bottle round mouth), and dispersed for 5 hours using a paint conditioner (manufactured by RED DEVIL Co., 1400-OH). After the zirconium dioxide beads were separated, an oil phase dispersion was prepared. The oil phase dispersion 37.80 g was put in a 100 mL polypropylene cup, and a mixture of the water phase raw materials shown below 25.2 g was added while stirring at a stirring speed of 3000 rpm using a high-speed emulsifying / dispersing machine (manufactured by PRIMIX Co., "T.K. ROBOMIX"). The stirring was continued for 5 minutes at 3000 rpm, and an emulsion preparation was prepared. 2Titanium oxide powder 8.75 g of φ 0.5 mm zirconium dioxide beads (manufactured by SHINMARU ENTERPRISES Co., Ltd.) 130 g as a dispersion medium were put in a 100 mL bottle (manufactured by NIKKO HANSEN Co., Ltd.: J bottle round mouth), and after dispersion for 5 hours using a paint conditioner (manufactured by RED DEVIL Co., 1400-OH), the zirconium dioxide beads were separated to prepare an oil phase dispersion. The oil phase dispersion 37.80 g was put in a 100 mL polypropylene cup, and using a high-speed emulsifying / dispersing machine (manufactured by PRIMIX Co., "T.K. ROBOMIX"), while stirring at a stirring speed of 3000 rpm, a mixture of the water phase raw materials 32.2 g shown below was added, and stirring was performed at 3000 rpm for 5 minutes to prepare an emulsion preparation. The viscosity of the emulsion preparation was measured using a B-type viscometer under the conditions of No. 2 rotor, 25°C, and 60 rpm, and was 72 mPa-s.

[0166] (Oil phase raw materials)

[0167] • Dimethicone 29.75 g: "KF-96L-1.5cs" manufactured by SHIN-ETXU CHEMICAL CO., LTD.

[0168] • Liquid paraffin 4.375 g: "MORESCO WHITE P-70" manufactured by MORI SUGI CO., LTD.

[0169] • PEG-9 polydimethylsiloxane ethyl dimethicone 4.375 g: "KF-6028P" manufactured by SHIN-ETXU CHEMICAL CO., LTD.

[0170] (Water phase raw materials)

[0171] • Ion exchange water 22.4 g

[0172] • 1,3-butanediol 9.8 g

[0173] The emulsion preparation thus obtained at a concentration of 10 mass% was applied to a PET film (manufactured by PANAC Co., Ltd.: LUMIRROR 100T60) using an automatic bar coater equipped with a wire bar (No. 6), and a coating film was formed. With respect to the coating film, the color difference ΔE immediately after application and BIO SKIN was measured by the above-described method, and was 6.4, but the color difference ΔE after drying at room temperature for 24 hours was 4.0. Here, in the emulsion preparation of Comparative Example 3 using a commercially available titanium oxide powder, the color difference ΔE immediately after application was the same as that of the emulsion preparation of the present example, and was 6.4, but the color difference ΔE after drying was 4.4, which was larger than that of the emulsion preparation of the present example. Thus, the emulsion preparation of the present example can improve the transparency after drying compared to the conventional product.

[0174] In addition, the emulsified preparation was applied to a polypropylene film (Mitsui Chemicals Tohcello Co., Ltd.: no-printing OPP sheet #40) using an automatic bar coater equipped with a wire bar (No. 6) to form a coating film. The light transmittance of the coating film was measured using a spectrophotometer ("U-4100" manufactured by Hitachi High-Technologies Corporation, using an integrating sphere) under the following conditions. A graph in which the light transmittance is plotted against the wavelength is shown in FIG. 2 together with the light transmittance of the emulsified preparation of Comparative Example 3. Figure 8 It was found that the blocking effect of UVA (320 to 400 nm) was greater than that of Comparative Example 3 in which a commercially available titanium oxide powder was used. In addition, the light transmittance at 400 nm was 66.0%, the light transmittance at 450 nm was 78.9%, and the wavelength at which the light transmittance reached 50% was 374 nm.

[0175] • Scanning speed: 300 nm / min

[0176] • Sampling interval: 2 nm

[0177] • Measuring wavelength: 250 to 700 nm

[0178] In addition, the use feeling, whitening, blueness, and transparency of the obtained emulsified preparation were evaluated by the above-described method, and a vote was taken as to which of the emulsified preparation of the present example and the emulsified preparation of Comparative Example 3 in which a commercially available titanium oxide powder was used was more excellent. As a result thereof, the emulsified preparation of the present example had a lower viscosity than the emulsified preparation of Comparative Example 3, the emulsified preparation was easily spread immediately after being dropped onto the skin, and the peculiar stickiness of the powder was greatly reduced, and thus, all of the 10 testers judged that the emulsified preparation had a good use feeling. In addition, with respect to the whitening, blueness, and transparency after being spread and dried, all of the 10 testers judged that the emulsified preparation in which the titanium oxide powder of the present example was used could suppress whitening and blueness and had transparency.

[0179] Further, in order to make the viscosity of the emulsified preparation close to that of the emulsified preparation of Comparative Example 3, an emulsified preparation having a concentration of 10 mass% was prepared in the same manner as described above except that the oil phase raw material was changed as shown below. The adjusted viscosity was 1278 mPa-s, which was measured using a B-type viscometer under the conditions of a No. 3 rotor, 25°C, and 60 rpm.

[0180] (Oil phase raw material)

[0181] • Dimethicone 28.33 g: "KF-96L-1.5cs" manufactured by Shin-Etsu Chemical Co., Ltd.

[0182] • Liquid paraffin 4.375 g: "MORESCO WHITE P-70" manufactured by MORESCO Corporation

[0183] • PEG-9 polydimethylsiloxane 4.375 g: "KF-6028P" manufactured by Shin-Etsu Chemical Co., Ltd.

[0184] • Aluminum stearate 1.42 g

[0185] The emulsified preparation after viscosity adjustment was uniformly applied to a PMMA plate in an amount of 1.3 mg / cm 2 After that, the SPF and UVAPF were measured using an SPF analyzer (Optometrics, Labsphere UV-2000S) after natural drying at room temperature for 30 minutes. As a result, the SPF was 12.6, and it was found that UVB was effectively shielded. In addition, the UVAPF was 4.7, and it was found that UVA was also effectively shielded. The evaluation results are summarized in Table 4.

[0186] Example 2

[0187] The slurry after addition of hydrochloric acid was aged at 100 to 105°C for 30 minutes, and a titanium oxide powder was produced in the same manner as in Example 1, except for this, and was analyzed and evaluated. The evaluation results are summarized in Tables 1 to 3.

[0188] Example 3

[0189] The slurry after addition of hydrochloric acid was aged at 50°C for 20 minutes, and a titanium oxide powder was produced in the same manner as in Example 1, except for this, and was analyzed and evaluated. The evaluation results are summarized in Tables 1 to 3. For the titanium oxide powder (after firing) having a specific surface area of about 60 m 2 / g, only the specific surface area was measured.

[0190] Comparative Example 1

[0191] To the slurry containing the above sodium titanate, 10.0 kg of 35 mass% hydrochloric acid was added, and was heated and aged at 100 to 105°C for 5 hours, and a titanium oxide powder was produced in the same manner as in Example 1, except for this, and was analyzed and evaluated. The evaluation results are summarized in Tables 1 to 3.

[0192] Comparative Example 2

[0193] which is an example of not impregnating a nitrogen-containing compound. To the slurry containing the above sodium titanate, 14.0 kg of 35 mass% hydrochloric acid was added and heated, and aged at 80°C for 10 minutes. The aged slurry was diluted with water to obtain a slurry containing 70 g / L of titanium oxide in terms of TiO2. The obtained titanium oxide contained rutile crystals. The titanium oxide slurry was warmed to 80°C, adjusted to pH 6.4 with 24 mass% sodium hydroxide aqueous solution, and then aged for 30 minutes. After the aging was completed, the obtained slurry was filtered, washed, and a filter cake of titanium oxide was obtained. The filter cake was dried, pulverized, and classified in the same manner as in Example 1 to obtain a titanium oxide powder (before firing). The subsequent processes were the same as in Example 1, and a titanium oxide powder (after firing) was produced, and analyzed and evaluated. The evaluation results are shown in Tables 1 to 3.

[0194] Example 4

[0195] which is an example of spraying ammonia water immediately before firing. In the same manner as in Comparative Example 2, 10 parts by mass of 24 mass% ammonia water was sprayed to 100 parts by mass of the obtained dried titanium oxide powder (before firing), and, other than this, in the same manner as in Comparative Example 2, a titanium oxide powder (after firing) was produced, and analyzed and evaluated. The evaluation results are shown in Tables 1 to 3.

[0196] Comparative Example 3

[0197] In the emulsion preparation having a concentration of 10 mass% produced in Example 1, a commercially available titanium oxide powder ("MT-100Z" manufactured by Tayca Corporation) was used instead of the surface-coated titanium oxide powder used, the dispersion time with a paint conditioner was set to 2 hours, and, other than this, the emulsion preparation was produced under the same conditions. "MT-100Z" is a titanium oxide powder containing spindle-shaped particles, the average short axis length of which is 7.9 nm, and the average long / short axis ratio of which is 4.0, and, in the same manner as in Example 1, surface-treated with polyaluminum chloride and sodium stearate. The spectrum obtained by ESCA measurement of this powder is shown in Figure 4 . It was found that no peak was observed at 395 to 402 eV. Here, the reason for shortening the dispersion time is that a viscosity increase occurs in the dispersion, and the color difference ΔE of the paint film immediately after coating from BIO SKIN is at the same level (6.4) as the product of the present application. The viscosity of this emulsion preparation was measured with a B-type viscometer under the conditions of No. 3 rotor, 25°C, and 60 rpm, and was 1492 mPa-s. The obtained emulsion preparation was evaluated in the same manner as in Example 1, and the results are shown in Table 4.

[0198] [Table 1]

[0199]

[0200] *1) The particles are too small to be processed by image.

[0201] [Table 2]

[0202]

[0203] *1) Firing after adding 24 mass% of ammonia water 10 mass%.

[0204] [Table 3]

[0205]

[0206] *1) Firing after adding 24 mass% of ammonia water 10 mass%.

[0207] [Table 4]

[0208]

Claims

1. A titanium dioxide powder, characterized in that: The peak intensity I of the anatase-type crystal in the X-ray diffraction measurement A The peak intensity I of the rutile-type crystal R The ratio I A / I R is 0.1 or less, The average minor axis length of the contained particles is 10–50 nm, and the average major-to-minor axis ratio is 1–3. Absorbance A at a wavelength of 450 nm 450 Absorbance A at a wavelength of 320 nm 320 Ratio A 450 / A 320 is 0.015 to 0.5, and, Containing nitrogen atoms, peaks originating from these nitrogen atoms were observed in the 395–402 eV range during ESCA (Electron Energy Dispersive Spectroscopy) measurements. The specific surface area of ​​the titanium dioxide powder is 25-100 m². 2 / g.

2. The titanium dioxide powder as described in claim 1, characterized in that: No peaks of anatase crystals were observed in the X-ray diffraction measurements.

3. The titanium dioxide powder as described in claim 1 or 2, characterized in that: Absorbance A at a wavelength of 600 nm 600 It is below 0.

1.

4. The titanium dioxide powder as described in claim 1 or 2, characterized in that: In L * a * b * In the color system, L * The value is 92-99, a * Values ​​range from -5 to 2, b * The value ranges from 3 to 30.

5. The titanium dioxide powder as described in claim 1 or 2, characterized in that: The surface of the titanium dioxide powder particles is coated with a layer of inorganic and / or organic compounds.

6. The titanium dioxide powder as described in claim 5, characterized in that: It is titanium dioxide powder formed by coating the surface of the particles with a layer of inorganic compound, which contains at least one element selected from aluminum, magnesium, calcium, silicon, zinc, titanium, zirconium, iron, cerium and tin.

7. The titanium dioxide powder as described in claim 5, characterized in that: It is a titanium dioxide powder formed by coating the surface of the particles with a layer of organic compound, wherein the organic compound is at least one selected from fatty acids or their salts, organosilicon compounds, coupling agents and fluorine compounds.

8. The titanium dioxide powder as described in claim 5, characterized in that: In L * a * b * In the color system, L * The value is 92-99, a * Values ​​range from -5 to 2, b * The value ranges from 2 to 30.

9. A dispersion, characterized in that: It is a dispersion formed by dispersing the titanium dioxide powder according to any one of claims 1 to 8 in a dispersion medium.

10. A cosmetic product, characterized in that: The titanium dioxide powder contained in any one of claims 1 to 8.

11. A coating, characterized in that: The titanium dioxide powder contained in any one of claims 1 to 8.

12. An ink, characterized in that: The titanium dioxide powder contained in any one of claims 1 to 8.

13. A toner, characterized in that: The additive contains titanium dioxide powder as described in any one of claims 1 to 8.

14. A method for manufacturing titanium oxide powder, wherein the titanium oxide powder is the titanium oxide powder according to claim 1, the method being characterized in that it comprises: An alkali metal hydroxide is added to an aqueous dispersion of aqueous titanium oxide to obtain an alkali metal titanate through an alkali metal titanate ... Adding hydrochloric acid to an aqueous dispersion of the alkali metal titanate yields an acidification process containing rutile-type titanium oxide crystals. The impregnation process that infuses nitrogen-containing compounds into the titanium oxide; and The firing process is carried out at 200–600℃.

15. The method for manufacturing titanium dioxide powder as described in claim 14, characterized in that: The specific surface area of ​​titanium oxide before firing is 120–300 m². 2 / g.

16. The method for manufacturing titanium dioxide powder as described in claim 14 or 15, characterized in that: In the impregnation process, alkaline nitrogen-containing compounds are used to neutralize the hydrochloric acid remaining after the acidification process, allowing the nitrogen-containing compounds to impregnate into the titanium oxide.

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