Metal oxide powder, dispersion liquid and cosmetic preparation

Metal oxide powders, dispersions and cosmetics

The present invention relates to metal oxide powders, dispersions and cosmetics. This application claims priority based on Japanese Patent Application No. 2015-255773 filed in Japan on December 28, 2015, the contents of which are incorporated herein by reference.

Metal oxide powders made of metal oxide particles such as titanium oxide, zinc oxide, and zirconium oxide are used for various purposes because they have a high refractive index and an ultraviolet shielding property. For example, the star-shaped titanium oxide particles described in Patent Document 1 have a light scattering ability of visible light to near-infrared light, and are contained in paints, resin compositions, plastic films, plastic plates and cosmetics. ,It's being used.

<p num="0003"><patcit num="1"><text>Japanese Patent No. 4382607</text></patcit></p>

<p num="0004">However, the paints and cosmetics containing the metal oxide powder as described above do not have sufficient adhesion to the object to be coated.</p><p num="0005"> The present invention has been made to solve the above problems, and an object of the present invention is to provide a metal oxide powder having excellent light scattering properties. Further, it is an object of the present invention to provide a dispersion liquid and a cosmetic containing this metal oxide powder, which have excellent light scattering properties and excellent adhesion to an object to be coated.</p>

<p num="0006"> One aspect of the present invention is a metal oxide powder using metal oxide particles as a forming material, wherein the metal oxide powder includes a first metal oxide particle having at least one protrusion and a first metal oxide particle. The first metal oxide particles have an average primary particle diameter of 100 nm or more and 1000 nm or less, and the second metal oxide particles have an average primary particle diameter of 100 nm or more. Provided is a metal oxide powder having a ratio of the total mass of particles having a primary particle diameter of less than 100 nm to the total mass of the metal oxide powder of less than 100 nm of 0.3% by mass or more and 10% by mass or less.</p><p num="0007"> In one aspect of the present invention, the first metal oxide particles include a plurality of first protrusions that project radially in a substantially vertical direction from the central axis of the first metal oxide particles, and the central axis. A pair of second protrusions that project in a direction in which the tips are separated from each other along the above, and between each tip of the first protrusion and each tip of the second protrusion. It preferably forms a ridge and has a star-shaped morphology as a whole.</p><p num="0008"> In one aspect of the present invention, the metal oxide particles are preferably titanium oxide particles.</p><p num="0009"> In one aspect of the present invention, a surface treatment layer using a surface treatment agent as a forming material may be provided on the surface of the metal oxide particles.</p><p num="0010"> One aspect of the present invention provides a dispersion liquid containing the above metal oxide powder and a dispersion medium.</p><p num="0011"> One aspect of the present invention provides a cosmetic containing at least one selected from the group consisting of the above metal oxide powder and the above dispersion liquid.</p>

<p num="0012"> According to one aspect of the present invention, a metal oxide powder having excellent light scattering properties is provided. Further, a dispersion liquid and a cosmetic containing the metal oxide powder, having excellent light scattering properties and excellent adhesion to an object to be coated are provided.</p>

<figref num="1">It is a top view which shows typically the 1st metal oxide particles which concerns on this Embodiment.</figref><figref num="2">It is sectional drawing which follows the AA line of FIG.</figref><figref num="3">It is a top view which shows typically the modification of the 1st metal oxide particle which concerns on this embodiment.</figref><figref num="4">It is a scanning electron microscope image which shows the titanium oxide powder of Example 4.</figref><figref num="5">It is a scanning electron microscope image which shows the titanium oxide powder of Comparative Example 1.</figref><figref num="6">It is a scanning electron microscope image which shows the titanium oxide powder of the comparative example 2.</figref>

Hereinafter, embodiments of the metal oxide powder, the dispersion liquid, and the cosmetic according to the present invention will be described. The present embodiment will be specifically described in order to better understand the gist of the present invention, and is not limited to the present invention unless otherwise specified.

&lt;First Embodiment&gt; [Metal Oxide Powder] The metal oxide powder of the present embodiment uses metal oxide particles as a forming material. The metal oxide powder has a first metal oxide particle having at least one protrusion and a second metal oxide particle. Hereinafter, each form of the first metal oxide particles and the second metal oxide particles in the present embodiment will be described in detail with reference to the drawings as appropriate.

For the average primary particle size used in the following description, a value obtained as follows from an image obtained by a scanning electron microscope (hereinafter, SEM) is adopted. The primary particle size of each metal oxide particle in the SEM image can be measured using a measuring instrument such as a caliper or an image analyzer.

For the primary particle size, the value that maximizes the distance between the parallel lines when each metal oxide particle in the SEM image is sandwiched between two parallel lines (maximum ferret diameter (JIS Z 8827-1: 2008)) is adopted. do. 100 of these primary particle diameters are randomly measured, and the weighted average of the obtained measured values is taken as the average primary particle diameter.

When the metal oxide particles form aggregates (secondary particles), the primary particle diameters of the primary particles constituting the secondary particles are randomly measured to be 100 and used as the average primary particle diameter.

For the mass of the metal oxide particles, the value obtained as follows is adopted. First, 100 primary particle diameters of metal oxide particles are randomly measured on an SEM image. Next, the volume of the metal oxide particles is calculated from the primary particle diameter according to the shape of the metal oxide particles. Further, the mass of the metal oxide particles is calculated by multiplying this volume by the density of the metal oxides constituting the metal oxide particles.

(First Metal Oxide Particles) The first metal oxide particles according to the present embodiment refer to those having an average primary particle diameter of 100 nm or more and 1000 nm or less. Within this range, the average primary particle size of the first metal oxide particles is preferably 150 nm or more and 800 nm or less, more preferably 200 m or more and 600 nm or less, and further preferably 250 nm or more and 400 nm or less. ..

FIG. 1 is a plan view schematically showing the first metal oxide particles 100 according to the present embodiment. FIG. 2 is a cross-sectional view taken along the line AA of FIG. The first metal oxide particles 100 shown in FIGS. 1 and 2 have a plurality of first protrusions 1 protruding radially from the central axis Z in a substantially vertical direction of the central axis Z, and each other along the central axis Z. Includes a pair of second protrusions 2 that project in the direction in which the tips are separated. The first metal oxide particle 100 forms a ridge 10 between each tip 1a in the first protrusion 1 and each tip 2a in the second protrusion 1, and has a star-shaped shape as a whole. It is preferable to have.

When the first metal oxide particles 100 have a "star-shaped" shape, the first metal oxide particles 100 preferably have six first protrusions 1. At this time, it is preferable that the six first protrusions 1 are formed at substantially equal intervals in the circumferential direction of the central axis Z.

In FIG. 2, the distance between the two opposing tips 2a of the first metal oxide particle 100 having a star-shaped morphology is crystallographically determined by the type of the metal oxide particle and the exposed crystal plane. ing. For example, in the case of anatase-type titanium oxide whose main exposed crystal plane is the (101) plane, it is crystallographically 0.56 times the primary particle size (distance between two opposing tips 1a). Therefore, in the present embodiment, the distance between the two opposing tips 2a of the first metal oxide particle 100 having a star-shaped morphology is a crystaltically determined value (anathase-type titanium oxide). When the main exposed crystal plane is the (101) plane, it is regarded as 0.56 times the primary particle diameter), and the volume of the first metal oxide particle 100 having a star-shaped morphology is calculated.

The first metal oxide particles according to the present embodiment may have at least one protrusion selected from the group consisting of the first protrusion and the second protrusion. For example, in the metal oxide particles 101 shown in FIG. 3, it can be inferred that the first protrusion 1 is damaged when compared with the shape of the first metal oxide particles 100 shown in FIG. In such a case, the metal oxide particles 101 can be classified into the first metal oxide particles according to the present embodiment. That is, when it has a shape similar to that of the first metal oxide particle 100 shown in FIG. 1 and it is presumed that this shape is formed from the first metal oxide particle 100 due to breakage, the first It shall be regarded as the metal oxide particles of.

The proportion of the above-mentioned star-shaped particles in the first metal oxide particles is preferably 95% by mass or more, more preferably 99% by mass or more, and 100% by mass. Is even more preferable.

In the metal oxide powder of the present embodiment, the second metal oxide particles are preferably scattered between the first metal oxide particles. As a result, the dispersion liquid or cosmetic containing the metal oxide powder of the present embodiment has excellent adhesion to the surface to be coated.

The first metal oxide particles according to the present embodiment are preferably formed of, for example, titanium oxide, zinc oxide, zirconium oxide, tin oxide or the like. As the material for forming the first metal oxide particles, titanium oxide or zinc oxide is more preferable because of its high refractive index and excellent ultraviolet shielding property, and anatase having high hiding power and easily obtaining a color close to skin color. Molded titanium oxide is more preferred.

In the present embodiment, the anatase-type titanium oxide particles preferably have a (101) plane as the main exposed crystal plane. Here, "the main exposed crystal plane is the (101) plane" means that the exposed crystal plane is determined from the plane spacing by observing the lattice image with a field emission transmission electron microscope (hereinafter, FE-TEM). Yes, it means that other exposed crystal planes are virtually unobservable. In the present embodiment, when two or more types of main exposed crystal planes are observed when observing a lattice image with FE-TEM, it is assumed that the exposed surface is indefinite.

In the present embodiment, the above-mentioned metal oxide particles may contain an additive as long as the effects of the present invention are not impaired. Examples of the addition of the additive to the metal oxide particles include tin oxide particles to which antimony is added. The tin oxide particles to which this antimony is added are excellent in heat ray shielding property.

(Second Metal Oxide Particles) The second metal oxide particles according to the present embodiment have an average primary particle size of less than 100 nm. The lower limit of the average primary particle size of the second metal oxide particles according to the present embodiment is not particularly limited, but is preferably 1 nm or more in terms of stable production. That is, the average primary particle diameter of the second metal oxide particles according to the present embodiment is preferably 1 nm or more and less than 100 nm, preferably 3 nm or more and 70 nm or less, and more preferably 5 nm or more and 50 nm or less. It is preferably 10 nm or more and 30 nm or less, more preferably.

The second metal oxide particles according to the present embodiment are preferably formed of, for example, titanium oxide, zinc oxide, zirconium oxide, tin oxide or the like. As the material for forming the second metal oxide particles, titanium oxide or zinc oxide is more preferable because of its high refractive index and excellent ultraviolet shielding property, and anatase having high hiding power and easily obtaining a color close to skin color. Molded titanium oxide is more preferred.

In the present embodiment, the anatase-type titanium oxide particles preferably have a (101) plane as the main exposed crystal plane. The second metal oxide particles may be formed of the same forming material as the first metal oxide particles.

The second metal oxide particles according to this embodiment are not limited to a specific embodiment. Examples of the morphology of the second metal oxide particles include spheres, ellipses, rectangular parallelepipeds, cubes, polyhedra, triangular pyramids, quadrangular pyramids, spindles, protrusions, and stars. .. Further, the second metal oxide particles may be a mixture of metal oxide particles having a plurality of forms. The second metal oxide particle is preferably in a form having no acute-angled end portion in that an adhesion effect can be more easily obtained. Examples of such a form include a spherical shape, an elliptical shape, a rectangular parallelepiped shape, and a cubic shape.

When the second metal oxide particles include metal oxide particles having one or more protrusions, for example, when the metal oxide particles have a star-shaped shape or the like, the following embodiment is used. preferable. That is, the ratio of the total mass of the metal oxide particles having one or more protrusions having an average particle diameter of less than 100 nm to the total mass of the first metal oxide particles is 0.01% by mass or more and 7% by mass or less. It is more preferably 0.1% by mass or more and 5% by mass or less, and further preferably 1.3% by mass or more and 3% by mass or less.

The first metal oxide particles and the second metal oxide particles can be visually distinguished from the images obtained by SEM.

(Content) The content of metal oxide particles with respect to the total mass of metal oxide powder can be measured by inductively coupled plasma (ICP) emission spectroscopy.

The total mass of the first metal oxide particles and the second metal oxide particles with respect to the total mass of the metal oxide powder according to the present embodiment is preferably 99.7% by mass or more, more preferably 99.8% by mass or more, and 99.9% by mass. More preferably by mass% or more.

For example, when the first metal oxide particles and the second metal oxide fine particles are titanium oxide particles, the content of the titanium oxide particles in the titanium oxide powder is preferably 99.7% by mass or more, preferably 99.8. It is more preferably mass% or more, and further preferably 99.9 mass% or more.

Among the components contained in the metal oxide powder of the present embodiment, the components other than the first metal oxide particles and the second metal oxide particles include, for example, adsorption adhering to the metal oxide particles. Examples include water and impurities derived from raw materials. When the metal oxide particles are titanium oxide particles, for example, iron oxide may be contained.

The ratio of the total mass of particles having an average primary particle diameter of 100 nm or more and 1000 nm or less (first metal oxide particles) to the total mass of the metal oxide powder according to the present embodiment is 90% by mass or more and 99.7% by mass. It is preferably 92% by mass or more and 99.5% by mass or less, more preferably 94% by mass or more and 99.0% by mass or less, and further preferably 96% by mass or more and 98.5% by mass or less. ..

The ratio of the total mass of particles having an average primary particle diameter of less than 100 nm (second metal oxide particles) to the total mass of the metal oxide powder according to the present embodiment is 0.3% by mass or more and 10% by mass or less. , 0.5% by mass or more and 8% by mass or less, more preferably 1% by mass or more and 6% by mass or less, and further preferably 1.5% by mass or more and 4% by mass or less.

The metal oxide powder of the present embodiment can be used as a dispersion liquid or cosmetics when the ratio of the total mass of particles having a primary particle diameter of less than 100 nm to the total mass of the metal oxide powder satisfies the above conditions. When contained, the dispersion liquid and cosmetics exhibit excellent adhesion to an object to be coated such as skin.

[Method for producing metal oxide powder] In the method for producing metal oxide powder according to the present embodiment, the first metal oxide particles and the second metal oxide particles are prepared and mixed. It is a method of manufacturing by. An example of the method for producing the metal oxide powder according to the present embodiment will be described. In the following description, star-shaped titanium oxide particles having an average primary particle diameter of 100 nm or more and 1000 nm or less are used as the first metal oxide particles. Further, as the second metal oxide particles, anatase-type granular titanium oxide particles having an average primary particle diameter of 1 nm or more and 40 nm or less are used.

(Method for Producing Anatase-Type Star-shaped Titanium Oxide Particles) Star-shaped titanium oxide particles having an average primary particle diameter of 100 nm or more and 1000 nm or less can be produced by a known method. As a known method, for example, the production method described in JP-A-2009-292717 can be mentioned. Specifically, in the above-mentioned star-shaped titanium oxide particles, a hydrolysis product of titanium alkoxide or a titanium metal salt and an organic alkali are mixed in a predetermined solvent, and the obtained reaction solution is subjected to high temperature and high pressure. It can be produced by reacting (hydrothermal synthesis) in the presence of hot water.

Examples of the titanium alkoxide of the present embodiment include tetraethoxytitanium, tetraisopropoxytitanium, tetranormalpropoxytitanium, tetranormalbutoxytitanium and the like. As the titanium alkoxide, tetraisopropoxytitanium and tetranormalbutoxytitanium are preferable, and tetraisopropoxytitanium is more preferable, because it is easily available and the hydrolysis rate is easily controlled.

Examples of the titanium metal salt of the present embodiment include titanium tetrachloride and titanium sulfate.

In the present embodiment, in order to obtain high-purity star-shaped titanium oxide particles, it is preferable to use high-purity titanium alkoxide or high-purity titanium metal salt.

The hydrolysis product of this embodiment is obtained by hydrolyzing the above-mentioned titanium alkoxide or titanium metal salt. The obtained hydrolysis product is, for example, a cake-like solid, which is titanium hydroxide containing metatitanium acid or orthotitanium acid.

Hydrolyzed products obtained by hydrolyzing titanium alkoxides or titanium metal salts include by-products alcohols, hydrochloric acid and sulfuric acid. Since these inhibit the crystal growth of titanium oxide particles, it is preferable to wash them with pure water. As a method for washing the hydrolysis product, for example, a decantation method, a nutche method, and an ultrafiltration method are preferable.

The organic alkalis of the present embodiment have a function as a pH adjuster for the reaction solution and a function as a catalyst for hydrothermal synthesis described later. Examples of the organic alkalis include amines, high molecular weight amines and salts of high molecular weight amines, compounds having a five-membered ring containing ammonia or nitrogen, and the like.

Examples of the above-mentioned amines include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, monoethanolamine, diethanolamine, triethanolamine, tetramethylammonium chloride, and tetraethylammonium chloride. , Tetrapropylammonium chloride, tetrabutylammonium chloride, octylamine, laurylamine, stearylamine and the like.

Examples of the above-mentioned high molecular weight amine and high molecular weight amine salt include high molecular weight amine and high molecular weight amine salts composed of the above-mentioned amines.

Examples of the above-mentioned compound having a five-membered ring containing nitrogen include pyrrole, imidazole, indole, purine, pyrrolidine, pyrazole, triazole, tetrazole, isothiazole, isoxazole, frazane, carbazole or 1,5-diazabicyclo- [4.3. .0]-5-Nonen and the like.

Among the above-mentioned compounds having a five-membered ring containing nitrogen, the compound having a five-membered ring containing one nitrogen atom is preferable because it can produce titanium oxide particles having excellent crystallinity due to a narrow particle size distribution. Examples include pyrrole, indole, pyrrolidine, isothiazole, isoxazole, frazan, carbazole and 1,5-diazabicyclo- [4.3.0] -5-nonene.

Further, among the above-mentioned compounds having a five-membered ring containing one nitrogen atom, the compound having a saturated heterocyclic structure in the five-membered ring has a narrower particle size distribution than the above-mentioned compound and has excellent crystallinity. Is more preferable because it can be produced. For example, pyrrolidine and 1,5-diazabicyclo- [4.3.0] -5-nonene can be mentioned.

By using these nitrogen-containing five-membered ring compounds as catalysts for hydrothermal synthesis, anatase single-phase (anatase-type) star-shaped titanium oxide particles having a (101) main exposed crystal plane are obtained. be able to.

In the present embodiment, the blending amount of the organic alkalis is preferably 0.008 mol to 0.09 mol, more preferably 0.009 mol to 0.08 mol, still more preferably 0.01 mol to 0.07 mol, based on 1 mol of the titanium atom in the hydrolysis product. ..

The reaction solution of the present embodiment is obtained by mixing a hydrolysis product of titanium alkoxide or a titanium metal salt with organic alkalis in a predetermined solvent. The method for producing this reaction solution is not particularly limited as long as they can be uniformly dispersed. Examples of the method for preparing the reaction solution include a method of mixing the hydrolysis product and organic alkalis using a stirrer, a bead mill, a ball mill, an attritor, a dissolver or the like.

Further, in the present embodiment, water may be added to the reaction solution to adjust the concentration of the reaction solution. Examples of the water added to the reaction solution include deionized water, distilled water, pure water and the like.

The pH of the solution after the hydrothermal reaction according to this embodiment is preferably 9 to 12.5, preferably 10 to 12. In the present embodiment, the pH of the solution after the hydrothermal reaction can be controlled within the above range by controlling the blending amount of the organic alkalis.

In this embodiment, if the pH of the solution after the hydrothermal reaction is less than 9, the catalytic action of organic alkalis on nucleation may be reduced. As a result, the nucleation rate of the titanium oxide particles generated in the reaction solution becomes slow, and the number of nuclei of the titanium oxide particles in the reaction solution may decrease. As a result, the primary particle size of the individual titanium oxide particles becomes large, and the average primary particle size of the obtained titanium oxide particles may become too large.

On the other hand, if the pH of the solution after the hydrothermal reaction is higher than 12.5, the nucleation rate of the titanium oxide particles formed in the reaction solution becomes high, and the nuclei of the titanium oxide particles may increase in the reaction solution. As a result, the primary particle size of the individual titanium oxide particles becomes small, and the average primary particle size of the obtained titanium oxide particles may become too small.

In the present embodiment, the shape, average primary particle size, and particle size distribution of the obtained star-shaped titanium oxide particles can be controlled by adjusting the pH of the reaction solution.

The titanium atom concentration in the reaction solution according to the present embodiment can be appropriately set according to the desired average primary particle size of the titanium oxide particles. The titanium atom concentration in the reaction solution is preferably 0.05 mol / L to 3.0 mol / L, more preferably 0.1 mol / L to 2.5 mol / L. In the present embodiment, the titanium atom concentration in the reaction solution can be controlled within the above range by controlling the content of the hydrolysis product of titanium alkoxide or titanium metal salt.

In the present embodiment, when the titanium atom concentration in the reaction solution is smaller than 0.05 mol / L, the nucleation rate of titanium oxide particles generated in the reaction solution becomes slow, and the number of nuclei of titanium oxide particles in the reaction solution becomes slow. May decrease. As a result, the primary particle size of the individual titanium oxide particles becomes large, and the average primary particle size of the obtained titanium oxide particles may become too large.

On the other hand, if the titanium atom concentration in the reaction solution is higher than 3.0 mol / L, the nucleation rate of the titanium oxide particles generated in the reaction solution becomes high, and the number of nuclei of the titanium oxide particles in the reaction solution may increase. be. As a result, the primary particle size of the individual titanium oxide particles becomes small, and the average primary particle size of the obtained titanium oxide particles may become too small.

In the present embodiment, the molar ratio of titanium atoms to organic alkalis in the reaction solution is preferably in the range of 1.00: 0.008 to 1.00: 0.09, more preferably in the range of 1.00: 0.009 to 1.00: 0.08. When the molar ratio of titanium atoms to organic alkalis in the reaction solution is within the above range, titanium oxide particles having excellent crystallinity can be synthesized.

In the present embodiment, star-shaped titanium oxide particles can be produced by reacting the above-mentioned reaction solution in the presence of hot water at high temperature and high pressure. Such synthesis that reacts in the presence of hot water at high temperature and high pressure is called hydrothermal synthesis. In the hydrothermal synthesis of the present embodiment, a hermetically sealed high-temperature and high-pressure container (autoclave) is preferably used.

The heating temperature in the hydrothermal synthesis of the present embodiment is preferably 150 to 350 ° C, more preferably 200 to 350 ° C. In the present embodiment, the heating rate from room temperature to the above-mentioned temperature range is not particularly limited. Further, the pressure in the hydrothermal synthesis of the present embodiment is set to the pressure when the reaction solution is heated to the above temperature range in the closed container.

When the heating temperature in hydrothermal synthesis is within the above range, the solubility of the hydrolysis product of titanium alkoxide or titanium metal salt in water is improved, and the titanium alkoxide or titanium metal salt can be dissolved in the reaction solution. Furthermore, when the heating temperature in hydrothermal synthesis is within the above range, nuclei of titanium oxide particles can be generated and the nuclei can be grown. This makes it possible to produce the desired star-shaped titanium oxide particles.

The heating time in the hydrothermal synthesis of the present embodiment may be appropriately adjusted so that the metal oxide particles have a desired size, but is preferably 2 hours or more, and more preferably 3 hours or more. If the heating time is shorter than 2 hours, the raw material (hydrolyzed product of titanium alkoxide or titanium metal salt) is not consumed and the yield may decrease. Since the heating time is affected by the type and concentration of the raw material, a preliminary experiment may be carried out as appropriate, and the heating time may be set so that the metal oxide particles have a desired size. For example, the heating time may be 9 hours, 12 hours, 24 hours, 48 hours, or 72 hours. However, from the viewpoint of production efficiency, heating may be stopped when the metal oxide particles reach a desired size.

In the hydrothermal synthesis of the present embodiment, it is preferable to perform preheating (preheating the reaction solution at a temperature lower than the above temperature range). For example, when preheating is performed in the temperature range of 70 ° C to 150 ° C for 1 hour or more, only star-shaped titanium oxide particles having an average primary particle size of 100 nm or more and 1000 nm or less are formed. On the other hand, without preheating, in addition to the star-shaped titanium oxide particles having an average primary particle size of 100 nm or more and 1000 nm or less, granular titanium oxide particles having an average primary particle size of 1 nm or more and 40 nm or less are formed. Will be done.

In the present embodiment, examples of the method for extracting the star-shaped titanium oxide particles from the above-mentioned reaction solution include a method of solid-liquid separation by a decantation method, a nutche method, or the like. After taking out the star-shaped titanium oxide particles, the obtained star-shaped titanium oxide particles may be washed with pure water or the like for the purpose of reducing impurities.

The desired star-shaped titanium oxide particles can be obtained by drying the taken-out star-shaped titanium oxide particles by a known method.

In the present embodiment, it is preferable to forcibly stir the solution containing the hydrolysis product of titanium alkoxide or titanium metal salt or the reaction solution by using a stirrer such as a stirrer or a stirrer. The stirring speed in this embodiment is preferably 100 rpm to 300 rpm, for example.

(Method for Producing Anatase-Type Granular Titanium Oxide Particles) Anatase-type granular titanium oxide particles can be produced by a known method. As a known method, for example, the production method described in JP-A-2007-176753 can be mentioned. Specifically, the above-mentioned titanium oxide particles are produced by crystallization of a mixture of a hydrolyzed product of titanium alkoxide or a titanium metal salt as a starting material and an alkaline aqueous solution, water, diol or triol. be able to.

As another method, a hydrolysis product of titanium alkoxide or a titanium metal salt is mixed with a compound having a five-membered ring containing nitrogen to prepare a reaction solution, and the reaction solution is used as hot water at high temperature and high pressure. It can be produced by reacting (hydrothermal synthesis) in the presence of.

Examples of the titanium alkoxide of the present embodiment include tetraethoxytitanium, tetraisopropoxytitanium, tetranormalpropoxytitanium, tetranormalbutoxytitanium and the like. As the titanium alkoxide, tetraisopropoxytitanium and tetranormalbutoxytitanium are preferable, and tetraisopropoxytitanium is more preferable, because it is easily available and the hydrolysis rate is easily controlled.

Examples of the titanium metal salt of the present embodiment include titanium tetrachloride and titanium sulfate.

In the present embodiment, in order to obtain high-purity anatase-type granular titanium oxide particles, it is preferable to use high-purity titanium alkoxide or high-purity titanium metal salt.

The hydrolysis product of this embodiment is obtained by hydrolyzing the above-mentioned titanium alkoxide or titanium metal salt. The obtained hydrolysis product is, for example, a cake-like solid, which is titanium hydroxide containing metatitanium acid or orthotitanium acid.

Hydrolyzed products obtained by hydrolyzing titanium alkoxides or titanium metal salts include by-products alcohols, hydrochloric acid and sulfuric acid. Since these inhibit the crystal growth of titanium oxide particles, it is preferable to wash them with pure water. As a method for washing the hydrolysis product, for example, a decantation method, a nutche method, and an ultrafiltration method are preferable.

The nitrogen-containing five-membered ring compound of the present embodiment has a function as a pH adjuster for the reaction solution and a function as a catalyst for hydrothermal synthesis described later. Examples of the nitrogen-containing compound having a five-membered ring include pyrrole, imidazole, indole, purine, pyrrolidine, pyrazole, triazole, tetrazole, isothiazole, isoxazole, frazan, carbazole or 1,5-diazabicyclo- [4.3. 0] -5- Nonen and the like can be mentioned.

Among the above-mentioned compounds having a five-membered ring containing nitrogen, the compound having a five-membered ring containing one nitrogen atom is preferable because it can produce titanium oxide particles having excellent crystallinity due to a narrow particle size distribution. Examples include pyrrole, indole, pyrrolidine, isothiazole, isoxazole, frazan, carbazole and 1,5-diazabicyclo- [4.3.0] -5-nonene.

Further, among the above-mentioned compounds having a five-membered ring containing one nitrogen atom, the compound having a saturated heterocyclic structure in the five-membered ring has a narrower particle size distribution than the above-mentioned compound and has excellent crystallinity. Is more preferable because it can be produced. For example, pyrrolidine and 1,5-diazabicyclo- [4.3.0] -5-nonene can be mentioned.

By using these nitrogen-containing compounds having a five-membered ring as a catalyst for hydrothermal synthesis, granular titanium oxide particles having an anatase single-phase (anatase type) whose main exposed crystal plane is the (101) plane are obtained. be able to.

In the present embodiment, the blending amount of the compound having a five-membered ring containing nitrogen is preferably 0.1 mol to 1.0 mol, more preferably 0.1 mol to 0.7 mol, and 0.1 mol with respect to 1 mol of titanium atoms in the hydrolysis product. ~ 0.5 mol is more preferable.

The reaction solution of the present embodiment is obtained by mixing a hydrolysis product of titanium alkoxide or a titanium metal salt with a compound having a five-membered ring containing nitrogen. The method for producing this reaction solution is not particularly limited as long as they can be uniformly dispersed. Examples of the method for preparing the reaction solution include a method of mixing a compound having a five-membered ring containing a hydrolysis product and nitrogen using a stirrer, a bead mill, a ball mill, an attritor, a dissolver or the like.

Further, in the present embodiment, water may be added to the reaction solution to adjust the concentration of the reaction solution. Examples of the water added to the reaction solution include deionized water, distilled water, pure water and the like.

The pH of the solution after hydrothermal synthesis according to this embodiment is preferably 9 to 13, preferably 11 to 13. In the present embodiment, the pH of the solution after hydrothermal synthesis can be controlled within the above range by controlling the blending amount of the compound having a five-membered ring containing nitrogen.

In this embodiment, if the pH of the solution after hydrothermal synthesis is less than 9, the catalytic action of the nitrogen-containing five-membered ring compound on nucleation may be reduced. As a result, the nucleation rate of the titanium oxide particles generated in the reaction solution becomes slow, and the number of nuclei of the titanium oxide particles in the reaction solution may decrease. As a result, the primary particle size of the individual titanium oxide particles becomes large, and the average primary particle size of the obtained titanium oxide particles may become too large.

On the other hand, if the pH of the solution after hydrothermal synthesis is higher than 13, the nucleation rate of titanium oxide particles formed in the reaction solution becomes high, and the nuclei of titanium oxide particles may increase in the reaction solution. As a result, the primary particle size of the individual titanium oxide particles becomes small, and the average primary particle size of the obtained titanium oxide particles may become too small.

Further, if the pH of the solution after hydrothermal synthesis is higher than 13, the dispersibility of the reaction solution may change, and the particle size distribution of the produced titanium oxide particles may become too wide.

In the present embodiment, the shape, average primary particle size, and particle size distribution of the obtained anatase-type granular titanium oxide particles can be controlled by adjusting the pH of the reaction solution.

The titanium atom concentration in the reaction solution according to the present embodiment can be appropriately set according to the desired average primary particle size of the titanium oxide particles. The titanium atom concentration in the reaction solution is preferably 0.05 mol / L to 3.0 mol / L, more preferably 0.5 mol / L to 2.5 mol / L. In the present embodiment, the titanium atom concentration in the reaction solution can be controlled within the above range by controlling the content of the hydrolysis product of titanium alkoxide or titanium metal salt.

In the present embodiment, when the titanium atom concentration in the reaction solution is smaller than 0.05 mol / L, the nucleation rate of titanium oxide particles generated in the reaction solution becomes slow, and the number of nuclei of titanium oxide particles in the reaction solution becomes slow. May decrease. As a result, the primary particle size of the individual titanium oxide particles becomes large, and the average primary particle size of the obtained titanium oxide particles may become too large.

On the other hand, if the titanium atom concentration in the reaction solution is higher than 3.0 mol / L, the nucleation rate of the titanium oxide particles generated in the reaction solution becomes high, and the number of nuclei of the titanium oxide particles in the reaction solution may increase. be. As a result, the primary particle size of the individual titanium oxide particles becomes small, and the average primary particle size of the obtained titanium oxide particles may become too small.

Further, if the titanium atom concentration in the reaction solution is larger than 3.0 mol / L, the dispersibility of the reaction solution may change, and the particle size distribution of the produced titanium oxide particles may become too wide.

In the present embodiment, the molar ratio of the titanium atom to the compound having a five-membered ring containing nitrogen in the reaction solution is preferably in the range of 1.000.10 to 1.00: 1.00, more preferably in the range of 1.00.10 to 1.0: 00.70. preferable. When the molar ratio of the titanium atom and the compound having a five-membered ring containing nitrogen in the reaction solution is within the above range, titanium oxide particles having a narrow particle size distribution and excellent crystallinity can be synthesized.

In the present embodiment, anatase-type granular titanium oxide particles can be produced by reacting the above-mentioned reaction solution in the presence of hot water at high temperature and high pressure. Such synthesis that reacts in the presence of hot water at high temperature and high pressure is called hydrothermal synthesis. In the hydrothermal synthesis of the present embodiment, a hermetically sealed high-temperature and high-pressure container (autoclave) is preferably used.

The heating temperature in the hydrothermal synthesis of the present embodiment is preferably 150 to 350 ° C, more preferably 150 to 210 ° C. In the present embodiment, the heating rate from room temperature to the above-mentioned temperature range is not particularly limited. Further, the pressure in the hydrothermal synthesis of the present embodiment is set to the pressure when the reaction solution is heated to the above temperature range in the closed container.

When the heating temperature in hydrothermal synthesis is within the above range, the solubility of the hydrolysis product of titanium alkoxide or titanium metal salt in water is improved, and the titanium alkoxide or titanium metal salt can be dissolved in the reaction solution. Furthermore, when the heating temperature in hydrothermal synthesis is within the above range, nuclei of titanium oxide particles can be generated and the nuclei can be grown. This makes it possible to produce desired anatase-type granular titanium oxide particles.

The heating time in the hydrothermal synthesis of the present embodiment may be appropriately adjusted so that the metal oxide particles have a desired size, but is preferably 3 hours or more, and more preferably 4 hours or more. If the heating time is shorter than 3 hours, the raw material (hydrolyzed product of titanium alkoxide or titanium metal salt) is not consumed and the yield may decrease. Since the heating time is affected by the type and concentration of the raw material, a preliminary experiment may be carried out as appropriate, and the heating time may be set so that the metal oxide particles have a desired size. For example, the heating time may be 9 hours, 12 hours, 24 hours, 48 hours, or 72 hours. However, from the viewpoint of production efficiency, heating may be stopped when the metal oxide particles reach a desired size.

In the present embodiment, examples of the method for extracting anatase-type granular titanium oxide particles from the above-mentioned reaction solution include a method of solid-liquid separation by a decantation method, a nutche method, or the like. After taking out the anatase-type granular titanium oxide particles, the obtained granular titanium oxide particles may be washed with pure water or the like for the purpose of reducing impurities.

The desired anatase-type granular titanium oxide particles can be obtained by drying the extracted anatase-type granular titanium oxide particles by a known method.

In the present embodiment, it is preferable to forcibly stir the solution containing the hydrolysis product of titanium alkoxide or titanium metal salt or the reaction solution by using a stirrer such as a stirrer or a stirrer. The stirring speed in this embodiment is preferably 100 rpm to 300 rpm, for example.

(Method for Producing Metal Oxide Powder) The method for mixing the first metal oxide particles and the second metal oxide particles is not particularly limited, and examples thereof include a method of mixing using known instruments and devices. Examples of known instruments include mortars and the like. Known devices include, for example, a mixer, a ball mill, and the like.

According to the present embodiment, a metal having excellent light scattering properties and having excellent adhesion to the object to be coated (surface to be coated) when the dispersion liquid or cosmetic is contained in the dispersion liquid or cosmetic. Oxide powder can be obtained.

[Surface Treatment] In the present embodiment, a surface treatment layer using a surface treatment agent as a forming material may be provided on the surface of the metal oxide particles.

The above-mentioned surface treatment agent is not particularly limited, and can be appropriately selected depending on the use of the metal oxide powder. Hereinafter, an example of the surface treatment agent according to the present embodiment will be described by showing a case where the metal oxide powder of the present embodiment is contained in the cosmetic, but the surface treatment agent according to the present embodiment is not limited thereto. ..

The surface treatment agent of the present embodiment is not particularly limited as long as it is a surface treatment agent conventionally used in cosmetics, and either an inorganic component or an organic component can be used.

Examples of the above-mentioned inorganic component include silica, alumina and the like. Examples of the above-mentioned organic component include at least one selected from the group consisting of silicone compounds, organopolysiloxanes, fatty acids, fatty acid soaps, fatty acid esters and organic titanate compounds. Moreover, you may use a surfactant as an inorganic component or an organic component.

Examples of the above-mentioned silicone compound include silicone oils such as methylhydrogenpolysiloxane, dimethylpolysiloxane, and methylphenylpolysiloxane, and alkyls such as methyltrimethoxysilane, ethyltrimethoxysilane, hexyltrimethoxysilane, and octyltrimethoxysilane. silane, trifluoromethyl ethyltrimethoxysilane, fluoroalkyl silanes, such as heptadecafluorodecyltrimethoxysilane, methicone, hydrogenphosphite dimethicone, triethoxysilyl ethyl polydimethylsiloxyethyl dimethicone, Torieto silyl ethyl polydimethylsiloxy hexyl dimethicone, (Akuriretsu / Tridecyl acrylate / Triethoxysilylpropyl methacrylate / Dimethicone methacrylate) copolymer or triethoxycaprylylsilane and the like can be mentioned. Further, as the silicone compound, a copolymer of these silicone compounds may be used.

These silicone compounds may be used alone or in combination of two or more.

Examples of the above-mentioned fatty acids include palmitic acid, isostearic acid, stearic acid, lauric acid, myristic acid, behenic acid, oleic acid, logonic acid, 12-hydroxystearic acid and the like.

Examples of the above-mentioned fatty acid soap include aluminum stearate, calcium stearate, aluminum 12-hydroxystearate and the like.

Examples of the above-mentioned fatty acid ester include dextrin fatty acid ester, cholesterol fatty acid ester, sucrose fatty acid ester, starch fatty acid ester and the like.

Examples of the above-mentioned organic titanate compound include isopropyltriisostearoyl titanate, isopropyldimethacrylisostearoyl titanate, isopropyltri (dodecyl) benzenesulfonyl titanate, neopentyl (diallyl) oxy-tri (dioctyl) phosphate titanate or neopentyl (diallyl). Oxy-trineododecanoyl titanate and the like can be mentioned.

As described above, an example of the surface treatment agent according to the present embodiment has been described by showing the case where the metal oxide powder of the present embodiment is contained in the cosmetic. When the metal oxide powder of the present embodiment is contained in an ultraviolet shielding film, a gas barrier film, or the like, a general dispersant can be used in addition to the above-mentioned surface treatment agent. Examples of general dispersants include anionic dispersants, cationic dispersants, nonionic dispersants, silane coupling agents, wet dispersants and the like.

The method for forming the surface treatment layer using the surface treatment agent as the forming material on the surface of the metal oxide particles according to the present embodiment is not particularly limited, and a known method is adopted depending on the type of the surface treatment agent. be able to.

According to this embodiment, a metal oxide powder having excellent light scattering properties can be obtained. Further, by surface-treating the metal oxide powder with the above-mentioned surface treatment agent, the surface activity of the metal oxide powder can be suppressed and the dispersibility can be improved.

[Dispersion Liquid] The dispersion liquid of the present embodiment contains the above-mentioned metal oxide powder and the dispersion liquid. The dispersion liquid of the present embodiment also contains a paste-like dispersion having a high viscosity.

The dispersion medium contained in the dispersion liquid of the present embodiment can be appropriately selected depending on the use of the dispersion liquid. An example of the dispersion medium according to the present embodiment will be described below, but the dispersion medium of the present embodiment is not limited thereto.

Examples of the dispersion medium according to the present embodiment include alcohols, esters, ethers, ketones, hydrocarbons, amides, polysiloxanes, and modified products of polysiloxanes.

As the above-mentioned alcohols, for example, water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, octanol, glycerin and the like are preferable.

As the above-mentioned esters, for example, ethyl acetate, butyl acetate, ethyl lactate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, γ-butyrolactone and the like are preferable.

As the above-mentioned ethers, for example, diethyl ether, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (ethyl cellosolve), ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and the like are preferable. ..

As the above-mentioned ketones, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, cyclohexanone and the like are preferable.

As the above-mentioned hydrocarbon, for example, aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene, and cyclic hydrocarbons such as cyclohexane are preferable.

As the above-mentioned amides, for example, dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone and the like are preferable.

Examples of the above-mentioned polysiloxanes include chain polysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, and diphenylpolysiloxane, and cyclic polysiloxanes such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexanesiloxane. Polysiloxanes are preferred.

As the modified product of the above-mentioned polysiloxanes, for example, amino-modified polysiloxane, polyether-modified polysiloxane, alkyl-modified polysiloxane, fluorine-modified polysiloxane, and the like are preferable.

Other dispersion media include hydrocarbon oils such as liquid paraffin, squalane, isoparaffin, branched light paraffin, vaseline and selecin, and ester oils such as isopropylmillistate, cetylisooctanoate and glyceryltrioctanoate. , Silicone oils such as decamethylcyclopentasiloxane, dimethylpolysiloxane, methylphenylpolysiloxane, higher fatty acids such as uric acid, myristic acid, palmitic acid, stearic acid, lauryl alcohol, cetyl alcohol, stearyl alcohol, hexyldodecanol, iso A hydrophobic dispersion medium such as a higher alcohol such as stearyl alcohol may be used.

As the dispersion medium of the present embodiment, only one type may be used alone, or two or more types may be mixed and used.

The content of the dispersion medium contained in the dispersion liquid of the present embodiment can be appropriately adjusted according to the use of the dispersion liquid. The content of the dispersion medium with respect to the mass of the dispersion liquid is, for example, preferably 10% by mass or more and 99% by mass or less, more preferably 20% by mass or more and 90% by mass or less, and 30% by mass or more and 30% by mass or less. 80% by mass or less is more preferable.

The dispersion liquid of the present embodiment may contain additives generally used for the dispersion liquid as long as the effects of the present invention are not impaired. Examples of the above-mentioned additives include dispersants, stabilizers, water-soluble binders, thickeners, oil-soluble preservatives, ultraviolet absorbers, oil-soluble agents, oil-soluble pigments, oil-soluble proteins, vegetable oils and animal oils. Can be mentioned.

The method for producing the dispersion liquid according to the present embodiment is not particularly limited, and a known method can be adopted. For example, a dispersion liquid can be obtained by mechanically dispersing the metal oxide powder of the present embodiment with a dispersion medium by a dispersion device.

Examples of the above-mentioned disperser include a stirrer, a self-revolving mixer, a homomixer, an ultrasonic homogenizer, a sand mill, a ball mill, a roll mill, and the like.

According to this embodiment, it is possible to obtain a dispersion liquid having excellent light scattering properties and excellent adhesion to an object to be coated.

[Cosmetics] The cosmetics of the present embodiment include at least one selected from the group consisting of the above-mentioned metal oxide powders and dispersions. The cosmetic of another embodiment contains a cosmetic base raw material and at least one selected from the group consisting of the zinc oxide powder of the present embodiment and the dispersion liquid of the present embodiment. The cosmetic base raw material means various raw materials forming the main body of cosmetics, and examples thereof include oil-based raw materials, aqueous raw materials, surfactants, and powder raw materials. Examples of the oily raw material include fats and oils, higher fatty acids, higher alcohols, ester oils and the like. Examples of the aqueous raw material include purified water, alcohol, and a thickener. Examples of the powder raw material include colored pigments, white pigments, pearlizing agents, extender pigments and the like.

At least one selected from the group consisting of the metal oxide powder and the dispersion liquid of the present embodiment is used by blending with a conventionally known cosmetic. It is preferable to blend these components in the range of 0.1 to 50% by mass with respect to the mass of the cosmetic.

The method of blending the cosmetics according to the present embodiment is not particularly limited, and a known method can be adopted. For example, at least one selected from the group consisting of metal oxide powder and dispersion may be blended with the cosmetic base raw material in advance, and then other cosmetic ingredients may be blended, or the existing cosmetics may be blended. It may be blended later.

Examples of the cosmetics of the present embodiment include lotions, milky lotions, creams, ointments, foundations, lip balms, lipsticks, mascaras, eye shadows, eyebrows, nail enamel, and cheek colors.

The cosmetic of the present embodiment may be appropriately selected according to the characteristics of the metal oxide powder. For example, titanium oxide powder is preferably used in make-up cosmetics such as foundations because it has an ultraviolet shielding property and a hiding property that hides stains and wrinkles. As the material for forming the titanium oxide powder, it is preferable to use anatase-type titanium oxide particles because they have a color tone close to skin color, and anatase-type titanium oxide particles having a main exposed crystal plane (101) plane are used. It is more preferable to use it.

Here, for the main exposed surface of the metal oxide particles, the values obtained as follows are adopted. Using FE-TEM, observe the lattice image of the metal oxide particles and determine the exposed crystal plane from the interplanar spacing. If two or more types of main exposed crystal planes are observed at this time, it is assumed that the exposed surface is indefinite.

The mode of the cosmetic according to the present embodiment is not particularly limited, and examples thereof include solid, liquid, and gel. In addition, when the state of the cosmetic is liquid or gel, the dispersion form of the cosmetic is not particularly limited, and a water-in-oil (W / O type) emulsion, an oil-in-water (O / W type) emulsion, etc. Either an oil type or a water type can be selected.

The cosmetic of the present embodiment may contain known ingredients conventionally used in cosmetics in addition to the above-mentioned metal oxide powder, as long as the effects of the present invention are not impaired. Known ingredients include, for example, solvents, oils, surfactants, moisturizers, organic UV absorbers, antioxidants, thickeners, fragrances, colorants, bioactive ingredients, antibacterial agents and the like.

According to this embodiment, it is possible to obtain a cosmetic having excellent light scattering properties and excellent adhesion to an object to be coated.

&lt;Second Embodiment&gt; The difference between the first embodiment and the second embodiment of the present invention is that in the method for producing a metal oxide powder, the first metal oxide particles and the second metal oxide particles are used. It is to manufacture at the same time. Therefore, in the present embodiment, the description of the parts common to the first embodiment will be omitted as appropriate.

[Method for producing metal oxide powder] An example of the method for producing metal oxide powder according to the present embodiment will be described. In the following description, star-shaped titanium oxide particles having an average primary particle diameter of 100 nm or more and 1000 nm or less are used as the first metal oxide particles. Further, as the second metal oxide particles, anatase-type granular titanium oxide particles having an average primary particle diameter of 1 nm or more and 40 nm or less are used.

The titanium oxide powder of the present embodiment is prepared by mixing a hydrolysis product of titanium alkoxide or a titanium metal salt with organic alkalis, and this reaction solution is prepared in the presence of hot water at high temperature and high pressure. It can be produced by reacting (hydrolyzed synthesis).

As the titanium alkoxide or titanium metal salt of the present embodiment, the same ones that can be used in the first embodiment can be used. Therefore, the same hydrolysis products as those in the first embodiment can be obtained.

The organic alkalis of the present embodiment have a function as a pH adjuster for the reaction solution and a function as a catalyst for hydrothermal synthesis described later. Examples of the organic alkalis include amines, high molecular weight amines and salts of high molecular weight amines, compounds having a five-membered ring containing ammonia or nitrogen, and the like.

Examples of the above-mentioned amines include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, monoethanolamine, diethanolamine, triethanolamine, tetramethylammonium chloride, and tetraethylammonium chloride. , Tetrapropylammonium chloride, tetrabutylammonium chloride, octylamine, laurylamine, stearylamine and the like.

Examples of the above-mentioned high molecular weight amine and high molecular weight amine salt include high molecular weight amine and high molecular weight amine salts composed of the above-mentioned amines.

As the above-mentioned compound having a five-membered ring containing nitrogen, the same compounds as those used in the first embodiment can be used.

In the present embodiment, as in the first embodiment, water may be added to the reaction solution to adjust the concentration of the reaction solution.

The pH of the solution after the hydrothermal reaction according to this embodiment is preferably 9 to 11, preferably 9.5 to 10.5. In the present embodiment, the pH of the solution after the hydrothermal reaction can be controlled within the above range by controlling the blending amount of the organic alkalis.

In the embodiment, the shape, average primary particle size and particle size distribution of the obtained titanium oxide particles can be controlled by adjusting the pH of the reaction solution.

The titanium atom concentration in the reaction solution according to the present embodiment can be appropriately set according to the desired average primary particle size of the titanium oxide particles. The titanium atom concentration in the reaction solution is preferably 0.05 mol / L to 10 mol / L, more preferably 0.1 mol / L to 2.5 mol / L. In the present embodiment, the titanium atom concentration in the reaction solution can be controlled within the above range by controlling the content of the hydrolysis product of titanium alkoxide or titanium metal salt.

When the titanium atom concentration in the reaction solution according to the present embodiment is within the above range, the average primary particle size of the obtained titanium oxide particles can be controlled.

In the present embodiment, the reaction solution becomes a slurry by controlling the pH and the titanium atom concentration of the reaction solution so as to be within the above ranges.

In the present embodiment, the blending amount of the compound having a five-membered ring containing nitrogen is preferably 0.008 mol to 0.09 mol, more preferably 0.009 mol to 0.08 mol, and 0.01 mol with respect to 1 mol of titanium atoms in the hydrolysis product. ~ 0.07 mol is more preferable.

In the present embodiment, by performing hydrothermal synthesis using the above-mentioned reaction solution, the hydrolysis product of titanium alkoxide or the hydrolysis product of titanium metal salt in the reaction solution is decomposed at high temperature and under pressure. , Crystal growth of the obtained titanium source proceeds. In the hydrothermal synthesis of the present embodiment, as in the first embodiment, a hermetically sealed high-temperature and high-pressure container (autoclave) is preferably used.

The heating temperature in the hydrothermal synthesis of the present embodiment is preferably 200 ° C to 350 ° C, more preferably 210 ° C to 350 ° C, and even more preferably 220 ° C to 350 ° C. In the present embodiment, the heating rate from room temperature to the above-mentioned temperature range is not particularly limited.

The heating time in the hydrothermal synthesis of the present embodiment is preferably 2 hours or more, more preferably 6 hours to 12 hours.

In the hydrothermal synthesis of the present embodiment, it is preferable not to perform preheating (preheating the reaction solution at a temperature lower than the above temperature range). For example, when preheating is performed in the temperature range of 70 ° C to 150 ° C for 1 hour or more, only star-shaped titanium oxide particles having an average primary particle size of 100 nm or more and 1000 nm or less are formed, and a desired titanium oxide powder is formed. Cannot be obtained. On the other hand, by not performing preheating, in addition to the star-shaped titanium oxide particles having an average primary particle size of 100 nm or more and 1000 nm or less, titanium oxide particles having an average primary particle size of 1 nm or more and 40 nm or less are formed. Will be done.

As a method for taking out the titanium oxide powder from this reaction solution and drying it, the same method as in the first embodiment can be adopted.

In the present embodiment, it is preferable to forcibly stir the solution containing the hydrolysis product of titanium alkoxide or titanium metal salt or the reaction solution by using a stirrer such as a stirrer or a stirrer. The stirring speed in this embodiment is preferably 100 rpm to 300 rpm, for example.

In this way, star-shaped titanium oxide particles having an average primary particle size of 100 nm or more and 1000 nm or less and titanium oxide particles having an average primary particle size of 1 nm or more and 40 nm or less can be produced at the same time.

According to the present embodiment, a metal oxide powder having excellent light scattering properties and having excellent adhesion to an object to be coated is produced by the dispersion liquid or cosmetics when it is contained in the dispersion liquid or cosmetics. Obtainable. In the present embodiment, since the first metal oxide particles and the second metal oxide particles can be produced at the same time, it is easy to obtain a metal oxide powder in which both are uniformly mixed. Therefore, the dispersion liquid and the cosmetic of the present embodiment are superior to the dispersion liquid and the cosmetic of the first embodiment in adhesion to the object to be coated.

<p num="0172"> Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. Configurations can be added, omitted, replaced, and other modifications without departing from the spirit of the present invention. In this example, titanium oxide particles were used as an example of the metal oxide particles.</p><p num="0173">&lt;Preparation and evaluation of titanium oxide powder&gt; [Identification of crystal phase of titanium oxide particles] The crystal phase of titanium oxide particles was identified using an X-ray diffractometer (X'Pert PRO, manufactured by Spectris Co., Ltd.).</p><p num="0174">[Identification of the main exposed surface of the titanium oxide particles] The main exposed surface of the titanium oxide particles was identified using FE-TEM (JEM-2100F, manufactured by JEOL Ltd.). Specifically, the lattice image of titanium oxide particles was observed by FE-TEM, and the exposed crystal plane was determined from the plane spacing. At this time, when two or more types of main exposed crystal planes were observed, the exposed surface was considered to be indefinite.</p><p num="0175">[Measurement of primary particle size and average primary particle size of titanium oxide particles] The primary particle size of titanium oxide particles was measured using an image analyzer. For the primary particle size, the value that maximizes the distance between the parallel lines when each metal oxide particle in the SEM image is sandwiched between two parallel lines (maximum ferret diameter (JIS Z 8827-1: 2008)) is adopted. bottom. 100 of these primary particle diameters were randomly measured, and the weighted average of the obtained measured values was taken as the average primary particle diameter. When the titanium oxide particles formed aggregates (secondary particles), 100 primary particle diameters of the primary particles constituting the secondary particles were randomly measured and used as the average primary particle diameter.</p><p num="0176">[Measurement of mass of titanium oxide particles and particles having a primary particle size of less than 100 nm] A method of measuring the mass of titanium oxide particles will be described. First, 100 primary particle diameters (unit: nm) of titanium oxide particles were randomly measured on an SEM image. Then, from this primary particle size, the volume of titanium oxide particles (unit: nm)³) Was calculated.</p><p num="0177"> At this time, the volume of the star-shaped titanium oxide particles was determined as follows. First, assuming that the star-shaped titanium oxide particles are divided along a ridge line and a valley line sandwiched between the two ridge lines using a virtual plane including the central axis Z, the star-shaped titanium oxide particles are shown in FIG. It can be considered that 12 colored triangular pyramids are assembled in the plan view of. Here, it is assumed that the triangular pyramid, which is a constituent unit, considers the isosceles triangle on the right side of the figure obtained by dividing the cross-sectional view of FIG. 2 by the central axis Z as the bottom surface.</p><p num="0178"> When considered in this way, the height of the above-mentioned triangular pyramid is crystallographically 0.142 times the primary particle size. Further, regarding the isosceles triangle which is the bottom surface of the above-mentioned triangular pyramid, the base of the isosceles triangle is crystallographically 0.563 times the primary particle diameter. The height of the isosceles triangle is crystallographically 0.5 times the primary particle size.</p><p num="0179"> From these numerical values, the volume of the triangular pyramid, which is the above-mentioned constituent unit, can be obtained, and the volume of the star-shaped titanium oxide particles can be estimated by multiplying the volume of the obtained triangular pyramid by 12. That is, the volume of the star-shaped titanium oxide particles can be calculated by the following equation (1). In this example, the volume of the star-shaped titanium oxide particles was calculated based on the following formula (1). Volume of star-shaped titanium oxide particles = 0.08 × (primary particle size)³ ...(1) </p><p num="0180"> When the shape of the titanium oxide particles can be approximated by a sphere, the volume of the titanium oxide particles was calculated based on the formula for obtaining the volume of the sphere. The mass of the titanium oxide particles was calculated by multiplying this volume by the density of the titanium oxide particles.</p><p num="0181">[Measurement of Titanium Oxide Particle Content] The content of titanium oxide particles with respect to the mass of the titanium oxide powder was measured using a high-frequency ICP emission spectroscope (CIROS-120 EOP, manufactured by Rigaku Co., Ltd.).</p><p num="0182">[Production Example 1] (Hydrolyzed) 250 mL of pure water cooled to 10 ° C was placed in a glass container with a capacity of 1 L. 71 g of titanium tetraisopropoxide (manufactured by High Purity Chemical Laboratory Co., Ltd.) was added dropwise to this pure water using a dropping funnel while stirring at 300 rpm using a stirring blade, and the mixture was reacted for 1 hour. This gave a white aqueous suspension containing the hydrolysis product of titanium tetraisopropoxide. This aqueous suspension was suction filtered using Nutche and filter paper (manufactured by Toyo Filter Paper Co., Ltd., No. 2) to obtain a hydrolysis product of titanium tetraisopropoxide as a white cake-like solid. This cake-like solid was washed with 500 mL of pure water.</p><p num="0183">(Preparation of reaction solution) The hydrolyzed product of titanium tetraisopropoxide after washing and 1.4 g of a 26% aqueous solution of tetramethylammonium hydroxide (manufactured by Tokyo Chemical Industry Co., Ltd.) were placed in pure water, and the total mass was increased. The reaction solution was prepared so that the amount was 200 g. It was confirmed that the titanium atom concentration contained in the reaction solution was 1.25 mol / L.</p><p num="0184">(Hydrothermal synthesis) The above reaction solution was placed in an autoclave and preheated at 120 ° C. for 4 hours. Then, the reaction solution was heated at 270 ° C. for 12 hours and reacted to obtain a white aqueous suspension containing titanium oxide particles. This aqueous suspension was suction-filtered using Nutche and filter paper (manufactured by Toyo Filter Paper Co., Ltd., No. 2) to obtain a white cake-like solid containing titanium oxide particles. This cake-like solid was washed with 500 mL of pure water and dried at 120 ° C. for 24 hours to obtain titanium oxide particles of Production Example 1.</p><p num="0185"> It was found that the titanium oxide particles of Production Example 1 were star-shaped titanium oxide particles having an average primary particle diameter of 300 nm. It was found that the titanium oxide particles are anatase-type star-shaped titanium oxide particles whose main exposed crystal plane is the (101) plane.</p><p num="0186">[Production Example 2] (Hydrolyzed) 1 L of pure water cooled to 10 ° C was placed in a glass container with a capacity of 2 L. 71 g of titanium tetraisopropoxide (manufactured by High Purity Chemical Laboratory Co., Ltd.) was added dropwise to this pure water using a dropping funnel while stirring at 300 rpm using a stirring blade, and the mixture was reacted for 1 hour. This gave a white aqueous suspension containing the hydrolysis product of titanium tetraisopropoxide. This aqueous suspension was suction filtered using Nutche and filter paper (manufactured by Toyo Filter Paper Co., Ltd., No. 2) to obtain a hydrolysis product of titanium tetraisopropoxide as a white cake-like solid. This cake-like solid was washed with 500 mL of pure water.</p><p num="0187">(Preparation of reaction solution) The hydrolyzed product of titanium tetraisopropoxide after washing and 2.5 g of pyrrolidine (manufactured by Kanto Chemical Co., Inc.) are placed in pure water, and the reaction solution is adjusted to a total mass of 1 kg. Was prepared. It was also confirmed that the titanium atom concentration contained in the reaction solution was 0.25 mol / L.</p><p num="0188">(Hydrothermal synthesis) The above reaction solution was placed in an autoclave, heated at 200 ° C. for 9 hours, and reacted to obtain a white aqueous suspension containing titanium oxide particles. This aqueous suspension was suction-filtered using Nutche and filter paper (manufactured by Toyo Filter Paper Co., Ltd., No. 2) to obtain a white cake-like solid containing titanium oxide particles. This cake-like solid was washed with 500 mL of pure water and dried at 120 ° C. for 24 hours to obtain titanium oxide particles of Production Example 2.</p><p num="0189"> It was found that the titanium oxide particles of Production Example 2 were anatase-type granular titanium oxide particles having a (101) plane as the main exposed crystal plane. It was found that the average primary particle size of the titanium oxide particles was 20 nm.</p><p num="0190">[Production Example 3] Titanium oxide particles of Production Example 3 were obtained in the same manner as in Production Example 1 except that the reaction solution was heated at 250 ° C. for 8 hours without preheating.</p><p num="0191"> It was found that the titanium oxide particles of Production Example 3 contained titanium oxide particles whose main exposed crystal plane was the (101) plane. It was also found that star-shaped titanium oxide particles having an average primary particle size of 300 nm and granular titanium oxide particles having an average primary particle size of 20 nm were included.</p><p num="0192"> Table 1 shows the shape, average primary particle size, crystal phase, and main exposed crystal plane of the titanium oxide particles produced in Production Examples 1 to 3.</p><p num="0193"><tables num="1"><img file="WO2017115802A1_D0001.tif" /></tables></p><p num="0194">[Example 1] Titanium oxide of Example 1 by mixing 1.99 g of star-shaped titanium oxide particles prepared in Production Example 1 and 0.01 g of anatase-type granular titanium oxide particles prepared in Production Example 2 in a mortar. A powder was obtained.</p><p num="0195"> It was found that the obtained titanium oxide powder contained 0.5% by mass of particles having a primary particle size of less than 100 nm with respect to the total mass of the titanium oxide powder. It was found that the titanium oxide powder contained 99.9% by mass of star-shaped titanium oxide particles and anatase-type granular titanium oxide particles with respect to the total mass of the titanium oxide powder. That is, it was confirmed that high-purity titanium oxide particles were obtained without substantially containing anything other than titanium oxide particles.</p><p num="0196">[Example 2] Titanium oxide of Example 2 by mixing 1.84 g of star-shaped titanium oxide particles prepared in Production Example 1 and 0.16 g of anatase-type granular titanium oxide particles prepared in Production Example 2 in a mortar. A powder was obtained.</p><p num="0197"> It was found that the obtained titanium oxide powder contained 8% by mass of particles having a primary particle size of less than 100 nm with respect to the total mass of the titanium oxide powder. It was found that the titanium oxide powder contained 99.9% by mass of star-shaped titanium oxide particles and anatase-type granular titanium oxide particles with respect to the total mass of the titanium oxide powder.</p><p num="0198">[Example 3] 1.96 g of star-shaped titanium oxide particles prepared in Production Example 1 and 0.04 g of anatase-type granular titanium oxide particles prepared in Production Example 2 are mixed in a mortar to produce titanium oxide powder of Example 3. I got a body.</p><p num="0199"> It was found that the obtained titanium oxide powder contained 2% by mass of particles having a primary particle size of less than 100 nm with respect to the total mass of the titanium oxide powder. Furthermore, it was found that the titanium oxide powder contained 99.9% by mass of star-shaped titanium oxide particles and anatase-type granular titanium oxide particles with respect to the total mass of the titanium oxide powder.</p><p num="0200">[Example 4] Titanium oxide powder of Example 4 was obtained using 2 g of titanium oxide particles prepared in Production Example 3. FIG. 4 shows an SEM image of the titanium oxide powder according to Example 4. It was found that the obtained titanium oxide powder contained 1.5% by mass of particles having a primary particle size of less than 100 nm with respect to the total mass of the titanium oxide particles. It was also found that the star-shaped titanium oxide particles having a primary particle size of less than 100 nm were contained in an amount of 0.2% by mass based on the total mass of the particles having a primary particle size of less than 100 nm. It was found that the titanium oxide particles contained 99.9% by mass of star-shaped titanium oxide particles and anatase-type granular titanium oxide particles with respect to the total mass of the titanium oxide powder.</p><p num="0201">[Comparative Example 1] Using 2 g of the star-shaped titanium oxide particles produced in Production Example 1, the titanium oxide powder of Comparative Example 1 was obtained. FIG. 5 shows an SEM image of the titanium oxide powder according to Comparative Example 1. The obtained titanium oxide powder did not contain particles having a primary particle size of less than 100 nm.</p><p num="0202">[Comparative Example 2] Titanium oxide of Comparative Example 2 by mixing 1.6 g of star-shaped titanium oxide particles prepared in Production Example 1 and 0.4 g of anatase-type granular titanium oxide particles prepared in Production Example 2 in a mortar. A powder was obtained. FIG. 6 shows an SEM image of the titanium oxide powder according to Comparative Example 2. It was found that the obtained titanium oxide powder contained 20% by mass of particles having a primary particle size of less than 100 nm with respect to the total mass of the titanium oxide powder.</p><p num="0203">&lt;Preparation and Evaluation of Cosmetics&gt; A pseudo foundation was prepared by mixing titanium oxide powder and talc, which has been conventionally used as a base for foundations. Specifically, 2 g of titanium oxide powder of Examples and Comparative Examples and 8 g of talc were mixed in a mortar to obtain an evaluation powder.</p><p num="0204"> The obtained evaluation powder was placed on a 50 mm square substrate (Helioscreen HD-6, manufactured by Helioscreen) so that the film thickness was 3 μm, and an evaluation sample was prepared.</p><p num="0205">[Evaluation of light scattering property] The light scattering property of the titanium oxide powders of Examples 1 to 4 and Comparative Examples 1 to 2 was measured by measuring the integrated reflectance at 450 nm, 600 nm, and 750 nm of the obtained evaluation sample. Was evaluated. The integrated reflectance of the evaluation sample was measured with an ultraviolet-visible spectrophotometer (UV-3150, manufactured by Shimadzu Corporation). A barium sulfate (manufactured by Kanto Chemical Co., Inc.) green compact was used as a reference sample having an integrated reflectance of 100%.</p><p num="0206">[Adhesion evaluation] Adhesion test tape (CT-12 manufactured by Nichiban Co., Ltd.) was attached to the obtained evaluation sample so that it was 50 mm x 12 mm, and then slowly peeled off to measure the mass of the evaluation sample (A). ) Was measured. Using the mass (B) of the substrate and the mass (C) of the evaluation sample measured in advance, the peeling rate of the titanium oxide powders of Examples 1 to 3 was calculated based on the following formula (2). Peeling rate (%) = 100 × (CA) / (CB) ... (2)</p><p num="0207"> Table 2 shows the evaluation results of the light scattering property and adhesion of the titanium oxide powder produced in Examples and Comparative Examples.</p><p num="0208"><tables num="2"><img file="WO2017115802A1_D0002.tif" /></tables></p><p num="0209"> In this example, it was found that the titanium oxide powder of the present invention has excellent light scattering properties. Specifically, the evaluation powders of Examples 1 to 4 have higher integrated reflectances for all measured wavelengths and are excellent in light scattering properties as compared with the evaluation powders of Comparative Example 2. I understand.</p><p num="0210"> Further, it was found that the evaluation powder obtained by mixing the titanium oxide powder of the present invention and talc has excellent adhesion to the substrate. Specifically, the evaluation powders of Examples 1 to 4 had a lower peeling rate than the evaluation powders of Comparative Example 1, and were superior in adhesion to the substrate.</p><p num="0211">As described above, it was found that the cosmetic containing the titanium oxide powder of the present invention is excellent in both light scattering property and adhesion to the substrate. Therefore, it is considered that the cosmetic containing the titanium oxide powder of the present invention is excellent in hiding power and long-lasting makeup.</p>

It is possible to provide a metal oxide powder, a dispersion liquid and a cosmetic having excellent light scattering properties and excellent adhesion when contained in a dispersion liquid or a cosmetic.

1 1st protrusion 2 2nd protrusion 1a Tip at 1st protrusion 2a Tip at 2nd protrusion 10 Ridge 100, 101 1st metal oxide particle Z Central axis