WO2015033990A1 - Square-plate-shaped zinc oxide particles and method for producing same - Google Patents

Abstract

[Problem] Provided are square-plate-shaped zinc oxide particles having a novel shape which was unknown until now, and a method for producing the same. [Solution] Square-plate-shaped zinc oxide particles which are characterized in that the ratio of the length of the long side to the length of the short side (long-side length/short-side length) is 1.00-1.30, and the ratio of the length of the long side to the thickness (long-side length/thickness) is 3-100.

Description

Square plate-like zinc oxide particles and method for producing the same

The present invention relates to rectangular plate-like zinc oxide particles and a method for producing the same.

Zinc oxide particles have various properties such as cosmetics, resin compositions, paints, and inks that require these properties because they have UV shielding performance, electrical conductivity, visible light transparency, and infrared shielding effectiveness. Used in Control of the shape of the zinc oxide particles is performed so as to have excellent properties in each of these applications.

For example, Patent Document 1 describes flaky zinc oxide particles that can be used as an ultraviolet absorber, and describes the use of these in various applications. Furthermore, Patent Document 2 describes a zinc oxide powder in which primary particles are aggregated in a plate shape by hydrothermal synthesis. Patent Document 3 describes the production of plate-like zinc oxide particles. However, the known plate-like zinc oxide particles are usually hexagonal, and the square plate-like zinc oxide particles are not known and the production method is not known.

JP-A-9-137152 JP 2007-223874 A JP-A-7-187673

An object of this invention is to provide the square plate-like zinc oxide particle which is a novel shape which is not known until now, and its manufacturing method.

In the present invention, the ratio of the long side length to the short side length (long side length / short side length) is 1.00 to 1.30, and the long side length to thickness ratio (long side) The square plate-like zinc oxide particles are characterized in that the side length / thickness is 3 to 100.

The length of the long side is preferably 5 μm or more and 100 μm or less.
The rectangular plate-like zinc oxide particles preferably have a zinc oxide content of 85% by weight or more, and no foreign phase is observed from the XRD pattern.

The present invention has a step (1) of mixing raw material zinc oxide, zinc nitrate, and trivalent and / or tetravalent metal elements in a solvent, and the method for producing the rectangular plate-like zinc oxide particles as described above But there is.

In the above production method, it is preferable that a part or all of the trivalent and / or tetravalent metal element is present in the raw material zinc oxide.
In the above production method, it is preferable that a part or all of the trivalent and / or tetravalent metal element is dissolved and / or dispersed in the solvent.

This invention is also cosmetics containing the square plate-shaped zinc oxide particle mentioned above.
The present invention is also a resin composition containing the square plate-like zinc oxide particles described above.
The present invention is also a coating composition containing the square plate-like zinc oxide particles described above.
The present invention is also an ink composition containing the square plate-like zinc oxide particles described above.

According to the present invention, there are provided square plate-like zinc oxide particles that have excellent ultraviolet shielding performance, conductivity, and slipperiness, and can be suitably used in the fields of cosmetics, resin compositions, paints, inks, and the like. can do.

1 is an electron micrograph of zinc oxide obtained in Example 1. FIG. 4 is a view showing an electron micrograph of zinc oxide obtained in Example 3. FIG. 4 is an electron micrograph of zinc oxide obtained in Example 4. FIG. 6 is a view showing an electron micrograph of zinc oxide obtained in Example 5. FIG. 6 is an electron micrograph of zinc oxide obtained in Example 6. FIG. 6 is an electron micrograph of zinc oxide obtained in Example 7. FIG. 6 is an electron micrograph of zinc oxide obtained in Example 8. FIG. 2 is an electron micrograph of zinc oxide obtained in Comparative Example 1. FIG. 6 is an electron micrograph of zinc oxide obtained in Comparative Example 2. FIG. It is a figure which shows the electron micrograph of the zinc oxide obtained by the comparative example 3. It is a figure which shows the electron micrograph of the zinc oxide obtained by the comparative example 4. 2 is a diagram showing an XRD pattern of zinc oxide obtained in Example 1. FIG. 4 is a diagram showing an XRD pattern of zinc oxide obtained in Example 3. FIG. 6 is a diagram showing an XRD pattern of zinc oxide obtained in Example 4. FIG. 6 is a diagram showing an XRD pattern of zinc oxide obtained in Example 5. FIG. 6 is a diagram showing an XRD pattern of zinc oxide obtained in Example 6. FIG. 6 is a diagram showing an XRD pattern of zinc oxide obtained in Example 7. FIG. 6 is a diagram showing an XRD pattern of zinc oxide obtained in Example 8. FIG. 6 is a diagram showing an XRD pattern of zinc oxide obtained in Comparative Example 1. FIG. It is a figure which shows the XRD pattern of the zinc oxide obtained by the comparative example 2. It is a figure which shows the XRD pattern of the zinc oxide obtained by the comparative example 3. 2 is a diagram showing a UV reflectance spectrum of zinc oxide obtained in Example 1. FIG.

The present invention is zinc oxide particles having a square plate shape. The square plate shape is a quadrangular plate shape, preferably a square plate shape, a rectangular plate shape, a parallelogram plate shape, or a rhombus plate shape. The rectangular plate-like zinc oxide particles of the present invention have a ratio of the length of the long side to the length of the short side, that is, the length of the long side / the length of the short side is 1.00 to 1.30. Square plate-like zinc oxide particles having a ratio of length to thickness, that is, the length / thickness of the long side is 3 to 100. Zinc oxide particles having such a square plate shape have not been known so far and have been completed by the present invention. Since the square plate-like zinc oxide particles of the present invention are plate-like, they have good slip properties, and particularly when used as a blending component in cosmetics, excellent usability is expected. Furthermore, it can mix | blend with a resin composition, a coating material, ink, etc. In the present invention, “long side” refers to the length of the longest side of the quadrangular shape, and “short side” refers to the length of the shortest side of the quadrangular shape. In the case of a square plate shape or a rhombus plate shape, the lengths of all sides are the same. In this case, the length of the long side / the length of the short side is 1.00.

The square plate-like zinc oxide particles of the present invention have a long side length / short side length of 1.00 to 1.30.
Here, the length of the long side / the length of the short side is shown in a photograph taken with a scanning electron microscope (SEM, JSM-7000F, manufactured by JEOL Ltd.) at a magnification such that 10 particles can be contained in one field of view. The length of each long side / the length of the short side of each plate-like particle was calculated, and the average value of 50 plate-like particles was calculated.
By setting it as the said range, it is preferable at the point that slipperiness improves. The ratio is more preferably 1.00 to 1.25.

The rectangular plate-like zinc oxide particles of the present invention have a long side length / thickness of 3 to 100. By setting it as the thing within the said range, it will have a favorable plate-shaped shape and the objective of this invention mentioned above can be achieved favorably. The ratio is more preferably 4 to 70, and preferably 5 to 50. Here, the length / thickness of the long side is the same as when measuring the length of the long side / the length of the short side, and the length / thickness of the long side is calculated with the plate-like side face as the thickness. The average value of 50 plate-like particles is measured by a method of calculating.

The square plate-like zinc oxide particles of the present invention preferably have a long side length of 5 μm or more and 100 μm or less. If the thickness is less than 5 μm, there may be a problem in that the slipperiness is deteriorated, and if it exceeds 100 μm, a problem may occur in that the dispersibility in the resin is deteriorated. The lower limit of the length of the long side is more preferably 10 μm, and the upper limit of the length of the long side is more preferably 70 μm. Here, the length of the long side is the same as the case of measuring the length of the long side / the length of the short side, and the length of the long side of the plate-like particles is measured to obtain 50 plate-like particles. It is measured by the method of calculating the average value of.

The rectangular plate-like zinc oxide particles of the present invention preferably have a zinc oxide content of 85% by weight or more (in terms of metal element oxide). That is, it is preferable that the component other than zinc oxide contained as an impurity is a certain ratio or less, so that a decrease in the ultraviolet shielding effect can be suppressed. In addition, the content rate of zinc oxide here was analyzed with the wavelength dispersion type | mold fluorescence X-ray-analysis apparatus (PrimusII by Rigaku). The content is more preferably 90% by weight or more, and still more preferably 95% by weight or more.

Since the square plate-like zinc oxide particles of the present invention have good sliding properties, they have excellent performance when blended in cosmetics. Specifically, the average friction coefficient is preferably 0.85 or less, and more preferably 0.80 or less. Particles in such a numerical range show good performance in use feeling when blended in cosmetics. Further, the average deviation of the friction coefficient is preferably 0.015 or less, and more preferably 0.013 or less. When the average deviation of the friction coefficient is within the above range, it is preferable in that a smooth feel can be obtained. In addition, the average friction coefficient mentioned above and the average deviation of a friction coefficient are the values measured by the method explained in full detail in the Example.

In the method for producing rectangular plate-like zinc oxide particles of the present invention described in detail below, raw material zinc oxide and zinc nitrate are mixed in the presence of a certain amount of trivalent and / or tetravalent metal elements. Among these, some of the trivalent and / or tetravalent metal elements are incorporated in the rectangular plate-like zinc oxide, and the abundance thereof is preferably 7.5 mol% or less. When other elements are present beyond the above range, the crystallinity of zinc oxide is lowered and the ultraviolet shielding performance is lowered, which is not preferable. The upper limit is more preferably 4.5 mol%, still more preferably 3.6 mol%, and even more preferably 2.5 mol%. The lower limit is preferably 0.004 mol%, more preferably 0.04 mol%, still more preferably 0.25 mol%.

It is preferable that the heterogeneous phase is not recognized from the XRD pattern of the square plate-like zinc oxide particles of the present invention. “No heterogeneous phase is observed from the XRD pattern” here is measured with an X-ray diffractometer RINT-TTRIII (manufactured by Rigaku Corporation, X-ray source CuKα), and 2θ = 31.4 ° to 32.32. A peak with a peak top in the range of 1 °, a peak with a peak top in the range of 2θ = 34.0 ° to 34.9 °, and a peak with a peak top in the range of 2θ = 35.8 ° to 36.8 ° And zinc oxide is a peak having a peak top in the range of 2θ = 47.1 ° to 48.0 ° and a peak having a peak top in the range of 2θ = 56.2 ° to 57.2 °. This means that, among the peaks other than zinc oxide excluding the five peaks, those having a relative intensity (cps) ratio of 1/20 or more with respect to the zinc oxide main peak are not included. That is, the zinc oxide in such a state is substantially free of zinc element in a state other than the oxide due to the crystal structure.

The rectangular plate-like zinc oxide particles of the present invention as described above are a plate-like zinc oxide having a step (1) of mixing raw material zinc oxide, zinc nitrate, and trivalent and / or tetravalent metal elements in a solvent. It can be obtained by a method for producing particles. Such a manufacturing method is also one aspect of the present invention. That is, in the method for producing zinc oxide particles by dissolving and reprecipitating a part of the raw material zinc oxide in a zinc nitrate solution, the process is mixed in the presence of a trivalent and / or tetravalent metal element. It has characteristics. At this time, it is preferable that the raw material zinc oxide is not completely dissolved and is in a slurry state. By producing zinc oxide particles by such a novel production method, zinc oxide particles having the above-described characteristic shape can be obtained.

The production method of the present invention is characterized in that in the step (1), the raw material zinc oxide and zinc nitrate are mixed in the presence of a trivalent and / or tetravalent metal element. The tetravalent metal element may be dissolved in a slurry liquid medium, or may be mixed in the raw material zinc oxide in the state of oxide, hydroxide, etc. It may be in a state of being dispersed in the slurry in the form of a metal compound such as an oxide or a metal powder. That is, it may be present in any state such as ions, metals, oxides, hydroxides, etc., in the slurry as the reaction system regardless of the form.

More preferably, the step (1) is a trivalent and / or tetravalent metal element dissolved in a liquid medium in a slurry in a ionic state (first aspect), or raw material zinc oxide It is preferable to use a material containing a trivalent and / or tetravalent metal element (second embodiment).

The trivalent and / or tetravalent metal element is not particularly limited, and examples thereof include aluminum, tin, titanium, gallium, and indium. Among these, aluminum is preferable because it is inexpensive and has high safety. Moreover, when providing electroconductivity, aluminum or gallium is preferable and gallium is more preferable.

The trivalent and / or tetravalent metal element is preferably used in a proportion of 0.01 mol% to 10 mol% with respect to the zinc element of the raw material zinc oxide. It is preferably used at a rate of 0.1 mol% to 8.0 mol%, more preferably at a rate of 0.5 mol% to 5.0 mol%.

In the step (1), mixing is performed in a slurry containing raw material zinc oxide. The liquid medium constituting the slurry is preferably water or a mixed liquid of water and an aqueous organic solvent, and most preferably water. When using a liquid mixture of water and an aqueous organic solvent, the aqueous organic solvent can be mixed with water such as lower alcohols such as methanol and ethanol, water such as acetone, ethylene glycol, diethylene glycol, and polyethylene glycol at an arbitrary ratio. The aqueous organic solvent is preferably used in an amount of 1 to 30% by weight based on the total amount of the mixed solvent.

The raw material zinc oxide is not particularly limited in its particle diameter, particle shape, etc., but for example, those having a spherical shape, an elliptical shape, a petal shape, a needle shape, a tetrapot shape, a whisker shape, or a rod shape are used. can do.

The raw material zinc oxide may be a commercially available one, or may be synthesized and used. Examples of commercially available products include FINEX-50 (manufactured by Sakai Chemical Industry Co., Ltd.), zinc oxide type I (manufactured by Sakai Chemical Industry Co., Ltd.), and the like. The synthesis method in the case of synthesizing and using is not specifically limited, For example, the various zinc oxides obtained by baking the precursor compound which baked and becomes zinc oxide can be used.
The precursor compound is not particularly limited, and examples thereof include zinc hydroxide, zinc carbonate, basic zinc carbonate, zinc sulfate, and zinc nitrate.

In the case of producing square plate-like zinc oxide particles according to the second aspect, the raw material zinc oxide needs to contain a trivalent and / or tetravalent metal element. The method for producing zinc oxide containing a trivalent and / or tetravalent metal element is not particularly limited. For example, a zinc salt aqueous solution and a trivalent and / or tetravalent metal element-containing aqueous solution are mixed, By adjusting the pH of the mixed solution, a hydroxide precipitate is formed, and the resulting precipitate is filtered and then baked, a solid phase method, a coprecipitation method, a spray drying method, an in-liquid surface treatment method, etc. be able to.

An example of a method for producing the raw material zinc oxide containing trivalent and / or tetravalent metal elements by the above-described method will be described in detail below.
It does not specifically limit as a zinc salt compound which can be used as a zinc salt aqueous solution, Zinc salts, such as hydrochloric acid, nitric acid, a sulfuric acid, an acetic acid, an oxalic acid, a fatty acid, can be used. This can be dissolved in a solvent such as water, alcohol or a mixed solvent thereof and used as an aqueous zinc salt solution. Moreover, the zinc salt aqueous solution obtained by using metal zinc and zinc oxide as a raw material, and melt | dissolving these with an acid etc. may be sufficient. In the above method, it is preferable to use these compounds to form a 50 to 200 g / kg zinc salt aqueous solution as a metal salt containing no hydration water.

The trivalent and / or tetravalent metal element-containing aqueous solution is not particularly limited, and the raw materials include aluminum nitrate, aluminum sulfate, aluminum chloride, gallium nitrate, gallium sulfate, gallium chloride, gallium oxide, indium chloride, indium oxide, and tetrachloride. Titanium, titanyl sulfate, titanium tetraisopropoxide, sodium titanate, tin nitrate, tin chloride, tin oxide, zirconium chloride, zirconium nitrate, zirconium oxide and the like can be used.
In the above method, these compounds are preferably used to form an aqueous solution containing 10 to 300 g / kg of a trivalent and / or tetravalent metal element as a metal salt containing no hydration water.

And these are mixed in the ratio according to the predetermined amount of trivalent and / or tetravalent metal elements required in the raw material zinc oxide. Thereafter, by adjusting the pH to be in the range of 7 to 8, zinc hydroxide partially containing a trivalent and / or tetravalent metal element is precipitated, filtered, and if necessary By washing with water and firing, zinc oxide containing a trivalent and / or tetravalent metal element can be obtained.

In the step (1), when preparing a slurry containing raw material zinc oxide and zinc nitrate, the raw material zinc oxide is preferably in a concentration of 1 to 40% by weight based on the total amount of the mixed slurry. The concentration is more preferably 1 to 20% by weight, and further preferably 5 to 10% by weight. The zinc nitrate is preferably 5 to 50% by weight as a metal salt containing no hydration water with respect to the total amount of the above mixed slurry. The concentration is more preferably 10 to 40% by weight, and further preferably 15 to 30% by weight. By setting it within the above range, the desired square plate-like zinc oxide particles can be obtained satisfactorily.

In the step (1), it is necessary to use zinc nitrate. This is because when other zinc salt compounds such as zinc chloride and zinc sulfate are used, the square plate-like zinc oxide particles of the present invention having the specific shape as described above cannot be obtained.

In the first aspect, in the step (1), an ionic compound of a trivalent and / or tetravalent metal element is added to the slurry, and in the presence of a trivalent and / or tetravalent metal ion. Mix.
In said 2nd aspect, in the said process (1), it mixes using the raw material zinc oxide containing a trivalent and / or tetravalent metal element.

The ionic compound of a trivalent and / or tetravalent metal element that can be used in the first aspect is not particularly limited. For example, aluminum nitrate, aluminum sulfate, aluminum chloride, gallium nitrate, gallium sulfate, Examples include gallium chloride, indium chloride, titanium tetrachloride, titanyl sulfate, titanium tetraisopropoxide, sodium titanate, tin nitrate, tin chloride, zirconium chloride, and zirconium nitrate.

In addition, in the said 1st aspect, using the raw material zinc oxide containing the trivalent and / or tetravalent metal element mentioned above as raw material zinc oxide, the conditions of both the first aspect and the second aspect There is no problem even if the mixing is performed under the condition of having both.

The mixing in the above step (1) can be carried out while stirring the slurry at a normal pressure, hydrothermal, or solvothermal slurry temperature of 30 ° C. to 200 ° C. The slurry temperature is more preferably 45 ° C. to 180 ° C., and further preferably 45 ° C. to 110 ° C. Although mixing time depends on the mixing temperature, it can be carried out in 0.5 to 5 hours.

The slurry can be prepared by mixing raw material zinc oxide and other necessary components in a liquid medium. Moreover, you may use a dispersing agent as needed. The dispersant is not particularly limited, and the amount used is preferably 1 to 10% by weight.

The slurry having been subjected to the above step (1) is then filtered, and washed with water, dried and fired as necessary to obtain the desired rectangular plate-like zinc oxide particles.

When firing, the firing temperature is preferably 300 to 1000 ° C. If it is 300 degreeC or more, it is preferable at the point which crystallinity is high and the ultraviolet-ray shielding effect becomes high. When the step (1) is completed, a square plate shape is formed, and the firing atmosphere is not particularly limited, and examples thereof include air, oxygen, nitrogen, carbon dioxide, hydrogen, argon, and methane. When imparting electrical conductivity, firing in a reducing atmosphere is preferred. Although the firing time depends on the firing temperature, it is preferably 1 to 5 hours. The square plate-like zinc oxide obtained by firing in this manner is particularly preferable because it is easy to prevent a heterogeneous phase from being seen from the XRD pattern.

After obtaining the square plate-like zinc compound particles by the step (1), surface treatment may be performed as necessary. For example, the slurry containing the square plate-like zinc compound particles after completion of the mixing in the step (1) may be subjected to surface treatment as it is, and then the filtered square plate-like zinc compound is again treated. The surface treatment may be performed by dispersing in water, the surface treatment may be performed by dispersing again in water after firing, or the surface treatment may be performed as it is after firing. Also good. The square plate-like zinc compound referred to here is a square plate-like zinc oxide and / or a square plate-like zinc compound that is fired to form a square plate-like zinc oxide, which may be a kind of compound or several types. A mixture of these compounds may also be used.

The surface treatment is not particularly limited, and the surface on which a film is formed with at least one compound selected from the group consisting of silicon oxide, hydrated silicon oxide, aluminum oxide, and aluminum hydroxide. Examples thereof include surface treatment with a water repellent organic compound, surface treatment with a coupling agent such as a silane coupling agent and a titanium coupling agent. A combination of these two or more surface treatments may be used.

The formation of the film with at least one compound selected from the group consisting of silicon oxide, silicon oxide hydrate, aluminum oxide, and aluminum hydroxide is performed by using a Si source compound and / or an Al source compound. Can be performed by a method such as precipitation on the powder surface by hydrolysis, thermal decomposition, or the like. As the Si source compound and / or a Al source compound, tetraalkoxysilane or its hydrolytic condensate, sodium silicate, potassium silicate, aluminum alkoxide or its hydrolytic condensate, sodium aluminate and the like, readily SiO ₂ Ya A compound that converts to Al (OH) ₃ or Al ₂ O ₃ can be used.

Although it does not specifically limit as said hydrolysis, The method using acids, such as a sulfuric acid, hydrochloric acid, acetic acid, nitric acid, is mentioned. The neutralization method in this silica treatment method using an aqueous dispersion is a method in which an acid is added to the dispersion and then an Si source compound and / or an Al source compound is added. An Si source compound and / or an Al source is added to the dispersion. Either a method of adding an acid after adding the compound, or a method of simultaneously adding an Si source compound and / or an Al source compound and an acid to the dispersion may be used.

The treatment with the water repellent organic compound is not particularly limited, and examples thereof include silicone oil, alkyl silane, alkyl titanate, alkyl aluminate, polyolefin, polyester, metal soap, amino acid, amino acid salt and the like. Of these, silicone oil is preferred because of its chemical stability. Specific examples of this silicone oil include dimethylpolysiloxane (for example, KF-96A-100cs manufactured by Shin-Etsu Chemical Co., Ltd., DM10 manufactured by Asahi Kasei Wacker Silicone), methyl hydrogen polysiloxane (for example, KF-99P manufactured by Shin-Etsu Chemical Co., Ltd., Toray Industries, Inc.) SH1107C manufactured by Dow Corning), (dimethicone / methicone) copolymer (for example, KF-9901 manufactured by Shin-Etsu Chemical), methylphenyl silicone (for example, KF-50-100cs manufactured by Shin-Etsu Chemical), amino-modified silicone (for example, Shin-Etsu Chemical) KF-8015 manufactured by Toray Dow Corning, JP-8500 Conditioning Agent, ADM 6060 manufactured by Asahi Kasei Wacker Silicone, triethoxysilylethyl polydimethylsiloxyethyl dimethicone (for example, Shin-Etsu Chemical) Kogyo KF-9908), triethoxysilyl ethyl polydimethylsiloxy hexyl dimethicone (for example, a treatment by Shin-Etsu Chemical KF-9909).

Examples of the treatment with the silane coupling agent include vinyltris (2-methoxyethoxy) silane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, 3-glycol. Sidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltri Methoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopro Rumethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminotriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxy Silane hydrochloride, 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanate B pills triethoxysilane, tetramethoxysilane, tetraethoxysilane, methyl trimethoxysilane, methyl triethoxysilane, phenyl triethoxy silane, hexamethyldisilazane, hexyltrimethoxysilane and decyltrimethoxysilane.
The treatment with the titanium coupling agent includes tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, tetramethyl titanate, titanium acetylacetonate, titanium tetraacetylacetonate, titanium ethylacetoacetate. , Titanium octanediolate, titanium lactate, titanium triethanolamate, and polyhydroxytitanium stearate.

When the surface treatment is performed, the surface treatment is preferably performed at a ratio of 1 to 10% by weight with respect to the total amount of the powder after the treatment. By setting it within the range, it is preferable in terms of improving slipperiness, improving moisture resistance, and improving dispersibility in the resin.

The square plate-like zinc oxide particles of the present invention can be mixed with other components and blended in cosmetics, inks, paints and the like. In particular, since it has the above-mentioned characteristics, it is preferable in that a cosmetic having excellent stability and ultraviolet shielding effect can be obtained.

The cosmetic is not particularly limited, and by mixing the square plate-like zinc oxide particles of the present invention with cosmetic raw materials as necessary, UV protective cosmetics such as sunscreen agents; base makeup cosmetics such as foundations A point makeup cosmetic such as lipstick can be obtained. Moreover, since it has the characteristic of ultraviolet-ray shielding ability, when using for cosmetics, the outstanding ultraviolet-ray shielding performance is shown.

The cosmetics can be in any form of oily cosmetics, aqueous cosmetics, O / W cosmetics, and W / O cosmetics. Especially, it can use especially suitably in a sunscreen agent.

The cosmetic may be used in combination with any aqueous component or oily component that can be used in the cosmetic field. The aqueous component and the oil component are not particularly limited, and examples thereof include oil agents, surfactants, humectants, higher alcohols, sequestering agents, natural and synthetic polymers, water-soluble and oil-soluble polymers, UV shielding agents, Various extracts, colorants such as organic dyes, preservatives, antioxidants, pigments, thickeners, pH adjusters, fragrances, cooling agents, antiperspirants, fungicides, skin activators, other agents, various It may contain components such as powder.

The oil agent is not particularly limited. For example, natural animal and vegetable oils and fats (for example, olive oil, mink oil, castor oil, palm oil, beef tallow, evening primrose oil, coconut oil, cacao oil, macadamia nut oil and the like); wax (for example, jojoba oil) Higher alcohols (eg, lauryl alcohol, stearyl alcohol, cetyl alcohol, oleyl alcohol, etc.); higher fatty acids (eg, lauric acid, palmitic acid, stearic acid, oleic acid, behenine), beeswax, lanolin, carnauba wax, candelilla wax, etc. Acids, lanolin fatty acids, etc .; higher aliphatic hydrocarbons such as liquid paraffin, solid paraffin, squalane, petrolatum, ceresin, microcrystalline wax, etc .; synthetic ester oils (eg, butyl stearate, hexyl laurate, diisopropyl adipate, di Sopropyl sebacate, octyldodecyl myristate, isopropyl myristate, isopropyl palmitate isopropyl myristate, cetyl isooctanoate, neopentyl glycol dicaprate); silicone derivatives (eg, silicone oils such as methyl silicone and methyl phenyl silicone) Etc. can be exemplified. Furthermore, oil-soluble vitamins, preservatives, whitening agents, and the like can be added.

Examples of the surfactant include a lipophilic nonionic surfactant and a hydrophilic nonionic surfactant. The lipophilic nonionic surfactant is not particularly limited. For example, sorbitan monooleate, sorbitan monoisostearate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan sesquioleate, sorbitan trioleate. Sorbate, sorbitan fatty acid esters such as diglycerol sorbitan penta-2-ethylhexylate, diglycerol sorbitan tetra-2-ethylhexylate, mono-cotton oil fatty acid glycerin, glyceryl monoerucate, glyceryl sesquioleate, glyceryl monostearate, α, α '-Glycerol polyglycerin fatty acids such as pyroglutamate glyceryl oleate, glyceryl monostearate malate, propylene glycol monostearate Glycol fatty acid esters, hardened castor oil derivatives, glycerin alkyl ethers and the like.

The hydrophilic nonionic surfactant is not particularly limited. For example, POE sorbitan fatty acid esters such as POE sorbitan monooleate, POE sorbitan monostearate, POE sorbitan tetraoleate, POE sorbite monolaurate, and POE sorbite mono POE sorbite fatty acid esters such as oleate, POE sorbite pentaoleate, POE sorbite monostearate, POE glycerin fatty acid esters such as POE glycerol monostearate, POE glycerol monoisostearate, POE glycerol triisostearate, POE POE fatty acid esters such as monooleate, POE distearate, POE monodiolate, ethylene glycol stearate, POE lauryl ether, POE POE alkyl ethers such as yl ether, POE stearyl ether, POE behenyl ether, POE 2-octyldodecyl ether, POE cholestanol ether, POE alkyl phenyl ethers such as POE octyl phenyl ether, POE nonyl phenyl ether, POE dinonyl phenyl ether Plu-alonic types such as brulonic, POE / POP cetyl ether, POE / POP2-decyltetradecyl ether, POE / POP monobutyl ether, POE / POP hydrogenated lanolin, POE / POP alkyl ethers such as POE / POP glycerin ether, Tetronic PEO / TetraPOP ethylenediamine condensates, POE castor oil, POE hydrogenated castor oil, POE hydrogenated castor oil monoisos POE castor oil triisostearate, POE cured castor oil monopyroglutamic acid monoisostearic acid diester, POE castor oil cured castor oil derivatives such as POE cured castor oil maleic acid, POE beeswax and lanolin derivatives such as POE sorbite beeswax, Alkanolamides such as coconut oil fatty acid diethanolamide, lauric acid monoethanolamide, fatty acid isopropanolamide, POE propylene glycol fatty acid ester, POE alkylamine, POE fatty acid amide, sucrose fatty acid ester, POE nonylphenyl formaldehyde condensate, alkylethoxydimethylamine Examples thereof include oxide and trioleyl phosphate.

Examples of other surfactants include anionic surfactants such as fatty acid soaps, higher alkyl sulfates, POE lauryl sulfate triethanolamine, alkyl ether sulfates, alkyltrimethylammonium salts, alkylpyridinium salts, alkyl quaternary salts. Stability and skin irritation of cationic surfactants such as ammonium salts, alkyldimethylbenzylammonium salts, alkylamine salts, polyamine fatty acid derivatives, and amphoteric surfactants such as imidazoline amphoteric surfactants and betaine surfactants You may mix | blend in the range without a problem.

The humectant is not particularly limited, and examples thereof include xylitol, sorbitol, maltitol, chondroitin sulfate, hyaluronic acid, mucoitin sulfate, caronic acid, atelocollagen, cholesteryl-12-hydroxystearate, sodium lactate, bile salt, dl- Examples include pyrrolidone carboxylate, short-chain soluble collagen, diglycerin (EO) PO adduct, Isaiyobara extract, yarrow extract, and merirot extract.

The higher alcohol is not particularly limited, and examples thereof include linear alcohols such as lauryl alcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol, myristyl alcohol, oleyl alcohol, cetostearyl alcohol, monostearyl glycerin ether (batyl alcohol), 2-decyl. Examples thereof include branched chain alcohols such as tetradecinol, lanolin alcohol, cholesterol, phytosterol, hexyldodecanol, isostearyl alcohol, octyldodecanol, and the like.

The sequestering agent is not particularly limited. For example, 1-hydroxyethane-1,1-diphosphonic acid, 1-hydroxyethane-1,1-diphosphonic acid tetrasodium salt, sodium citrate, sodium polyphosphate, metaphosphoric acid Examples thereof include sodium, gluconic acid, phosphoric acid, citric acid, ascorbic acid, succinic acid, edetic acid and the like.

The natural water-soluble polymer is not particularly limited. For example, arabia gum, tragacanth gum, galactan, guar gum, carob gum, caraya gum, carrageenan, pectin, agar, quince seed (malmello), alge colloid (guckweed extract), starch (rice, rice, Corn, potato, wheat), plant polymers such as glycyrrhizic acid, microbial polymers such as xanthan gum, dextran, succinoglucan and pullulan, and animal polymers such as collagen, casein, albumin and gelatin. .

The semi-synthetic water-soluble polymer is not particularly limited. For example, starch-based polymers such as carboxymethyl starch and methylhydroxypropyl starch, methylcellulose, nitrocellulose, ethylcellulose, methylhydroxypropylcellulose, hydroxyethylcellulose, sodium cellulose sulfate, Examples thereof include cellulose polymers such as hydroxypropylcellulose, sodium carboxymethylcellulose (CMC), crystalline cellulose, and cellulose powder, and alginic acid polymers such as sodium alginate and propylene glycol alginate.

The synthetic water-soluble polymer is not particularly limited, and examples thereof include vinyl polymers such as polyvinyl alcohol, polyvinyl methyl ether, and polyvinyl pyrrolidone, and polyoxyethylene polymers such as polyethylene glycol 20,000, 40,000, and 60,000. Polymer, polyoxyethylene polyoxypropylene copolymer copolymer polymer, acrylic polymer such as sodium polyacrylate, polyethyl acrylate, polyacrylamide, polyglycerin, polyethyleneimine, cationic polymer, carboxyvinyl polymer, alkyl Modified carboxyvinyl polymer, (hydroxyethyl acrylate / acryloyl dimethyl taurine Na) copolymer, (Na acrylate / acryloyl dimethyl taurine Na) copolymer, (acryloyl dimethyl tantalum) Phosphorus ammonium / vinylpyrrolidone) copolymer, and (ammonium acryloyldimethyltaurate methacrylate Beheneth-25) cross-polymer.

The inorganic water-soluble polymer is not particularly limited, and examples thereof include bentonite, silicate AlMg (beegum), laponite, hectorite, and silicic anhydride.

The UV screening agent is not particularly limited. For example, paraaminobenzoic acid (hereinafter abbreviated as PABA), PABA monoglycerin ester, N, N-dipropoxy PABA ethyl ester, N, N-diethoxy PABA ethyl ester, N, N-dimethyl Benzoic acid UV screening agents such as PABA ethyl ester and N, N-dimethyl PABA butyl ester; Anthranilic acid UV screening agents such as homomenthyl-N-acetylanthranylate; Amyl salicylate, Menthyl salicylate, Homomentil salicylate, Octyl salicylate , Salicylic acid UV screening agents such as phenyl salicylate, benzyl salicylate, p-isopropanol phenyl salicylate; octylcinnamate, ethyl-4-isopropylcinnamate, methyl-2,5- Isopropyl cinnamate, ethyl-2,4-diisopropyl cinnamate, methyl-2,4-diisopropyl cinnamate, propyl-p-methoxycinnamate, isopropyl-p-methoxycinnamate, isoamyl-p-methoxycinnamate, 2- Ethoxyethyl-p-methoxycinnamate, cyclohexyl-p-methoxycinnamate, ethyl-α-cyano-β-phenylcinnamate, 2-ethylhexyl-α-cyano-β-phenylcinnamate, glyceryl mono-2-ethylhexa Cinnamic acid-based UV screening agents such as noyl-diparamethoxycinnamate; 2,4-dihydroxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone , 2, 2 ', 4,4'-tetrahydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-4'-methylbenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonate, 4 -Benzophenone-based UV shielding agents such as phenylbenzophenone, 2-ethylhexyl-4'-phenyl-benzophenone-2-carboxylate, 2-hydroxy-4-n-octoxybenzophenone, 4-hydroxy-3-carboxybenzophenone; (4'-methylbenzylidene) -d, l-camphor, 3-benzylidene-d, l-camphor, urocanic acid, urocanic acid ethyl ester, 2-phenyl-5-methylbenzoxazole, 2,2'-hydroxy- 5-methylphenylbenzotri Sol, 2- (2′-hydroxy-5′-t-octylphenyl) benzotriazole, 2- (2′-hydroxy-5′-methylphenylbenzotriazole), dibenzalazine, dianisoylmethane, 4-methoxy-4′- Examples thereof include t-butyldibenzoylmethane, 5- (3,3-dimethyl-2-norbornylidene) -3-pentan-2-one, and the like.

Other drug components are not particularly limited and include, for example, vitamin A oil, retinol, retinol palmitate, inosit, pyridoxine hydrochloride, benzyl nicotinate, nicotinamide, nicotinic acid DL-α-tocopherol, magnesium ascorbate phosphate, 2 Vitamins such as -O-α-D-glucopyranosyl-L-ascorbic acid, vitamin D2 (ergocaciferol), dl-α-tocopherol, dl-α-tocopherol acetate, pantothenic acid, biotin; estradiol, ethinylestradiol, etc. Hormones; amino acids such as arginine, aspartic acid, cystine, cysteine, methionine, serine, leucine and tryptophan; anti-inflammatory agents such as allantoin and azulene; whitening agents such as arbutin; astringents such as tannic acid; L Menthol, cooling agents and sulfur camphor such as, lysozyme chloride, can be mentioned pyridoxine chloride, and the like.

There are no particular limitations on the various extracts, for example, Dokudami extract, Oat extract, Merirot extract, Odorikosou extract, Licorice extract, Peonies extract, Soap extract, Loofah extract, Kina extract, Yukinoshita extract, Clara extract, Kouhone extract, Fennel Extract, Primrose Extract, Rose Extract, Giant Extract, Lemon Extract, Shikon Extract, Aloe Extract, Shobu Root Extract, Eucalyptus Extract, Horsetail Extract, Sage Extract, Thyme Extract, Tea Extract, Seaweed Extract, Cucumber Extract, Clove Extract, Raspberry Extract, Melissa Extract , Carrot extract, marronnier extract, peach extract, peach leaf extract, mulberry extract, cornflower extract, hamamelis extract, placenta extract, thymus extract, silk extract, licorice Mention may be made of the kiss and the like.

Examples of the various powders include bengara, yellow iron oxide, black iron oxide, titanium mica, iron oxide-coated mica titanium, titanium oxide-coated glass flakes and other bright colored pigments, mica, talc, kaolin, sericite, titanium dioxide, Examples thereof include inorganic powders such as silica and organic powders such as polyethylene powder, nylon powder, crosslinked polystyrene, cellulose powder, and silicone powder. Preferably, a part or all of the powder component is hydrophobized by a known method with a substance such as silicones, fluorine compounds, metal soaps, oils, acyl glutamates in order to improve sensory characteristics and cosmetic durability. Used. Moreover, you may mix and use the other composite powder which does not correspond to this invention.

When using the rectangular plate-like zinc oxide particles of the present invention as an additive component to the ink, titanium oxide, Bengala, antimony red, cadmium yellow, cobalt blue, bitumen, ultramarine, carbon black, graphite and other colored pigments, and Examples of extender pigments include calcium carbonate, kaolin, clay, barium sulfate, aluminum hydroxide and talc. Further, as organic pigments, pigment components such as soluble azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, condensed polycyclic pigments; shellac resins, acrylic resins, styrene-acrylic resins, styrene-maleic acid resins It can be used in combination with a binder resin such as a binder resin such as a styrene-acrylic-maleic acid resin, a polyurethane resin, a polyester resin, or a polyamide resin; and a water-miscible organic solvent.

When the rectangular plate-like zinc oxide particles of the present invention are used as an additive component to a coating composition, coating film forming resins such as acrylic resins, polyester resins, and epoxy resins; various types such as colored pigments, extender pigments, and bright pigments Pigment: Can be used in combination with a curing catalyst, a surface conditioner, an antifoaming agent, a pigment dispersant, a plasticizer, a film-forming aid, an ultraviolet absorber, an antioxidant, and the like. The resin in the paint may be curable or non-curable.

Hereinafter, the present invention will be described in more detail with reference to examples. In addition, this invention is not limited to a following example.

Example 1
100 g of zinc oxide (1 type of zinc oxide manufactured by Sakai Chemical Industry Co., Ltd.) was added to a hydrochloric acid aqueous solution consisting of 259 g of 35 mass% hydrochloric acid (special grade reagent manufactured by Wako Pure Chemical Industries, Ltd.) and 647 g of ion-exchanged water, and the zinc oxide was completely To obtain a zinc chloride aqueous solution. Further, 9.39 g of aluminum nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) dissolved in 90 ml of ion-exchanged water was added to the prepared aqueous zinc chloride solution and dissolved until completely transparent. At this time, it was 2 mol% of aluminum with respect to the zinc element of zinc oxide. On the other hand, 300 g of sodium carbonate (special grade reagent manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 2000 ml of ion-exchanged water to prepare a sodium carbonate aqueous solution separately. The zinc chloride aqueous solution in which the aluminum nitrate was dissolved and the sodium carbonate aqueous solution were simultaneously neutralized at pH = 8 over 60 minutes to form a precipitate. Next, after aging for 30 minutes, the precipitate was sufficiently washed, filtered, and dried at 130 ° C. for 12 hours. The dried powder was crushed in an agate mortar to obtain a precursor before firing. The precursor before firing was fired in the atmosphere at 400 ° C. for 2 hours using an electric furnace to obtain fine raw material zinc oxide containing aluminum.
96 g of the obtained raw material zinc oxide was repulped with 480 ml of pure water to obtain a slurry. Then, it heated up to 90 degreeC, stirring the slurry. Subsequently, 428.38 g of zinc nitrate hexahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in ion-exchanged water to prepare 360 ml of an aqueous zinc nitrate solution. At this time, the weight of the aqueous zinc nitrate solution was 550.0 g. The aqueous solution was added to the repulp slurry over 2 hours and aged at 90 ° C. for 1 hour with stirring. After aging, the produced slurry was washed by filtration. Then, the square cake zinc compound was obtained by drying the obtained cake at 130 degreeC for 12 hours. The obtained square plate zinc compound was air baked at 450 ° C. for 1 hour to obtain square plate zinc oxide particles. The size and form of the obtained square plate-like zinc oxide particles were observed with a scanning electron microscope (SEM, JSM-7000F, manufactured by JEOL Ltd.). The ratio of the long side length to the short side length of the obtained rectangular plate-like zinc oxide particles was 1.09, and the long side length to thickness ratio was 9. The length of the long side was 24 μm. The obtained electron micrograph is shown in FIG. The zinc oxide content was 97.6% by weight, and no heterogeneous phase was observed from the XRD pattern. The XRD pattern is shown in FIG.

(Example 2)
In the same manner as in Example 1, except that 16.48 g of a gallium chloride aqueous solution prepared in advance with gallium chloride (manufactured by Yamanaka Futec Co., Ltd.) was added instead of aluminum nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) Zinc oxide particles were obtained. At this time, gallium was 2 mol% with respect to the zinc element of the raw material zinc oxide. The gallium content concentration of the gallium chloride aqueous solution was 10.6 wt%, and the gallium content concentration was measured with an ICP emission spectroscopic analyzer (SPS1700 HVR type manufactured by Seiko Denshi Kogyo). The particle size and morphology of the obtained square plate-like zinc oxide were observed with a scanning electron microscope (SEM, JSM-7000F, manufactured by JEOL Ltd.). The ratio of the length of the long side to the length of the short side of the obtained rectangular plate-like zinc oxide particles was 1.04, and the ratio of the length of the long side to the thickness was 31. The length of the long side was 50 μm. The zinc oxide content was 96.7% by weight, and no heterogeneous phase was observed from the XRD pattern.

Example 3
48 g of FINEX-50 (manufactured by Sakai Chemical Industry Co., Ltd., particle size: 0.02 μm) was repulped with 240 ml of pure water to obtain a slurry. An aqueous solution in which 4.51 g of aluminum nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 50 ml of ion-exchanged water was mixed in the slurry, and the temperature was raised to 90 ° C. while stirring the slurry. At this time, aluminum was 2 mol% with respect to the zinc element of the raw material zinc oxide. To the slurry, 180 ml of an aqueous zinc nitrate solution in which 214.19 g of zinc nitrate hexahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in ion-exchanged water was added over 2 hours and aged at 90 ° C. for 1 hour with stirring. . At this time, the weight of the aqueous zinc nitrate solution was 275.0 g. After aging, the produced slurry was washed with filtered water. Then, the square cake zinc compound was obtained by drying the obtained cake at 130 degreeC for 12 hours. The obtained square plate zinc compound was air baked at 450 ° C. for 1 hour to obtain square plate zinc oxide particles. The size and form of the obtained square plate-like zinc oxide particles were observed with a scanning electron microscope (SEM, JSM-840F, manufactured by JEOL Ltd.). The ratio of the length of the long side to the length of the short side of the obtained square plate-like zinc oxide particles was 1.03, and the ratio of the length of the long side to the thickness was 14. The length of the long side was 14 μm. The obtained electron micrograph is shown in FIG. The zinc oxide content was 98.0% by weight, and no heterogeneous phase was observed from the XRD pattern. The XRD pattern is shown in FIG.

Example 4
Square plate-like zinc oxide particles were obtained in the same manner as in Example 1 except that the obtained square plate-like zinc compound was air-fired at 700 ° C. for 1 hour. The size and form of the obtained square plate-like zinc oxide particles were observed with a scanning electron microscope (SEM, JSM-7000F, manufactured by JEOL Ltd.). The ratio of the length of the long side to the length of the short side of the obtained rectangular plate-like zinc oxide particles was 1.16, and the ratio of the length of the long side to the thickness was 11. The length of the long side was 22 μm. The obtained electron micrograph is shown in FIG. The zinc oxide content was 97.4% by weight, and no heterogeneous phase was observed from the XRD pattern. The XRD pattern is shown in FIG.

(Example 5)
Square plate-like zinc oxide particles were obtained in the same manner as in Example 1 except that 4.695 g of aluminum nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was added. At this time, aluminum was 1 mol% with respect to the zinc element of the raw material zinc oxide. The size and form of the obtained square plate-like zinc oxide particles were observed with a scanning electron microscope (SEM, JSM-7000F, manufactured by JEOL Ltd.). The ratio of the length of the long side to the length of the short side of the obtained rectangular plate-like zinc oxide particles was 1.13, and the ratio of the length of the long side to the thickness was 8. The length of the long side was 18 μm. The obtained electron micrograph is shown in FIG. The zinc oxide content was 98.9% by weight, and no heterogeneous phase was observed from the XRD pattern. The XRD pattern is shown in FIG.

(Example 6)
Square plate-like zinc oxide particles were obtained in the same manner as in Example 1 except that 18.78 g of aluminum nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was added. At this time, aluminum was 4 mol% with respect to the zinc element of raw material zinc oxide. The size and form of the obtained square plate-like zinc oxide particles were observed with a scanning electron microscope (SEM, JSM-7000F, manufactured by JEOL Ltd.). The ratio of the length of the long side to the length of the short side of the obtained rectangular plate-like zinc oxide particles was 1.11, and the ratio of the length of the long side to the thickness was 5. The length of the long side was 20 μm. The obtained electron micrograph is shown in FIG. The zinc oxide content was 96.3% by weight, and no heterogeneous phase was observed from the XRD pattern. The XRD pattern is shown in FIG.

(Example 7)
The obtained square plate-like zinc compound was put in an alumina boat, and a tubular furnace was used to circulate a mixed gas of 0.285 liter / minute of nitrogen gas and 0.015 liter / minute of hydrogen gas at 200 ° C./hour. Square plate-like zinc oxide particles were obtained in the same manner as in Example 1 except that the temperature was raised to 750 ° C. and maintained for 8 hours. The size and form of the obtained square plate-like zinc oxide particles were observed with a scanning electron microscope (SEM, JSM-7000F, manufactured by JEOL Ltd.). The ratio of the length of the long side to the length of the short side of the obtained square plate-like zinc oxide particles was 1.20, and the ratio of the length of the long side to the thickness was 12. The length of the long side was 17 μm. The obtained electron micrograph is shown in FIG. The zinc oxide content was 97.2% by weight, and no heterogeneous phase was observed from the XRD pattern. The XRD pattern is shown in FIG.

(Example 8)
The obtained square plate-like zinc compound was put in an alumina boat, and a tubular furnace was used to circulate a mixed gas of 0.285 liter / minute of nitrogen gas and 0.015 liter / minute of hydrogen gas at 200 ° C./hour. Square plate-like zinc oxide particles were obtained in the same manner as in Example 2 except that the temperature was raised to 750 ° C. and maintained for 8 hours. The size and form of the obtained square plate-like zinc oxide particles were observed with a scanning electron microscope (SEM, JSM-7000F, manufactured by JEOL Ltd.). The ratio of the long side length to the short side length of the obtained rectangular plate-like zinc oxide particles was 1.08, and the ratio of the long side length to the thickness was 36. The long side length was 58 μm. The obtained electron micrograph is shown in FIG. The zinc oxide content was 96.3% by weight, and no heterogeneous phase was observed from the XRD pattern. The XRD pattern is shown in FIG.

(Comparative Example 1)
Zinc oxide particles were obtained in the same manner as in Example 6 except that 428.38 g of zinc nitrate hexahydrate was changed to 196.29 g of zinc chloride (manufactured by Wako Pure Chemical Industries, Ltd.). The size and form of the obtained zinc oxide particles were observed with a scanning electron microscope (SEM, JSM-7000F, manufactured by JEOL Ltd.). The shape of the obtained zinc oxide particles was indefinite, and the ratio of the length of the long side to the length of the short side and the ratio of the length of the long side of the square plate to the thickness could not be measured. The obtained electron micrograph is shown in FIG. The zinc oxide content was 77.3% by weight, and a heterogeneous phase was observed from the XRD pattern. The XRD pattern is shown in FIG.

(Comparative Example 2)
Zinc oxide particles were obtained in the same manner as in Example 5 except that 428.38 g of zinc nitrate hexahydrate was changed to 414.11 g of zinc sulfate heptahydrate (manufactured by Wako Pure Chemical Industries, Ltd.). The size and form of the obtained zinc oxide particles were observed with a scanning electron microscope (SEM, JSM-7000F, manufactured by JEOL Ltd.). The shape of the obtained zinc oxide particles was indefinite, and the ratio of the length of the long side to the length of the short side and the ratio of the length of the long side of the square plate to the thickness could not be measured. The obtained electron micrograph is shown in FIG. The zinc oxide content was 79.9% by weight, and a heterogeneous phase was observed from the XRD pattern. The XRD pattern is shown in FIG.

(Comparative Example 3)
Zinc oxide particles were obtained in the same manner as in Example 1 except that 428.38 g of zinc nitrate hexahydrate was changed to 316.09 g of zinc acetate dihydrate (manufactured by Wako Pure Chemical Industries, Ltd.). The size and form of the obtained zinc oxide particles were observed with a scanning electron microscope (SEM, JSM-7000F, manufactured by JEOL Ltd.). The shape of the obtained zinc oxide particles was indefinite, and the ratio of the length of the long side to the length of the short side and the ratio of the length of the long side of the square plate to the thickness could not be measured. The obtained electron micrograph is shown in FIG. The zinc oxide content was 97.2% by weight, and no heterogeneous phase was observed from the XRD pattern. The XRD pattern is shown in FIG.

(Comparative Example 4)
Zinc oxide particles were obtained in the same manner as in Example 1 except that no aluminum nitrate nonahydrate was added. The size and form of the obtained zinc oxide particles were observed with a scanning electron microscope (SEM, JSM-7000F, manufactured by JEOL Ltd.). The shape of the obtained zinc oxide particles was needle-like, and the ratio of the length of the long side to the length of the short side and the ratio of the length of the long side of the square plate shape to the thickness could not be measured. The obtained electron micrograph is shown in FIG. Further, no heterogeneous phase was observed from the XRD pattern.

(Zinc oxide content)
The content of zinc oxide was analyzed with a wavelength dispersive X-ray fluorescence analyzer (Primus II manufactured by Rigaku Corporation).

(Powder X-ray diffraction evaluation)
The X-ray diffraction spectra shown in FIG. 12 to FIG. 21 show the results of analysis using an X-ray diffractometer RINT-TTRIII (manufactured by Rigaku Corporation). Measurement conditions are X-ray source CuKα, wavelength λ = 1.5418４, scanning mode FT, scanning range 2θ = 10.000 ° to 2θ = 60.000 °, step width 0.04 °, counting time 0.2 sec. Went.

(Long side length to short side length ratio, long side length to thickness ratio, and long side length)
The length of the long side / the length of the short side is a plate-like shape in a photograph taken with a scanning electron microscope (SEM, JSM-7000F, manufactured by JEOL Ltd.) at a magnification that allows 10 particles in one field of view. It is measured by a method of calculating the length of each long side / length of the short side of the particle and calculating the average value of 50 plate-like particles.
The ratio of the length of the long side to the thickness, that is, the length / thickness of the long side is the same as when measuring the length of the long side / the length of the short side. The length / thickness is calculated, and the average value of 50 plate-like particles is calculated. Further, the length of the long side is the same as the case of measuring the length of the long side / the length of the short side, the length of the long side of the plate-like particles is measured, and the average value of 50 plate-like particles It is measured by the method of calculating.

About the zinc oxide of the above Example and the comparative example, the manufacturing method and the shape of the obtained zinc oxide particle were put together in Table 1.

 

(Powder property evaluation)
(Volume resistivity)
The volume resistivity value of the square plate-like zinc oxide particles obtained in Example 7 and Example 8 was measured using the following method.
Place 0.8 g of sample into a 20 mmφ inner diameter vinyl chloride tube, sandwich the sample using a highly conductive jig that also serves as an electrode on both sides, and apply a load of 200 kgf / cm ^{2 to} the sample. A load was applied with a press. And the resistance value of the electrode both ends was measured with the tester, maintaining the state. From the resistance value, the volume specific resistance value was determined by the following equation.
(Formula) Volume resistivity (Ω · cm)
= Resistance value (Ω) × pressed area of sample (cm ² ) / pressed thickness (cm)
The volume resistivity value of Example 7 was 590 Ω · cm, and the volume resistivity value of Example 8 was 15 Ω · cm. From the above, it is clear that the square plate-like zinc oxide particles of the present invention are excellent in conductivity.

(Slip evaluation)
The slip properties of the square plate-like zinc oxide particles obtained in Example 1 and Example 4 were measured using the following method. A 25 mm wide double-sided tape is applied to the slide glass, the particles are placed on it, spread with a cosmetic puff, and the friction coefficient is measured with a friction tester KES-SE (manufactured by Kato Tech) using a silicone rubber friction element. The average friction coefficient MIU and the average deviation MMD of the friction coefficient were calculated from the average value of the friction coefficient (μ) for 20 mm, and the slipperiness was evaluated. The results are shown in Table 2.

From Table 2, it was clarified that the rectangular plate-like zinc oxide particles of Example 1 and Example 4 are particles having good slipperiness with a small variation in average friction coefficient and friction coefficient as compared with other zinc oxides. . For comparison, FINEX-50 (average particle size 20 nm), zinc oxide type I (average particle size 0.6 μm), and large particle zinc oxide LPZINC (average particle size 2 μm) were used.

(Ultraviolet shielding evaluation)
The ultraviolet shielding property of the square plate-like zinc oxide particles obtained in Example 1 was measured using the following method.
Reflectance was measured with an ultraviolet-visible infrared spectrophotometer (V-570 type spectrophotometer and ILN471 type integrating grade device manufactured by JASCO Corporation) while the obtained powder was compacted. Measurement was performed at a wavelength range of 300 to 800 nm and a measurement speed of 200 nm / min. The results are shown in FIG.
It can be seen from FIG. 22 that the rectangular plate-like zinc oxide obtained in Example 1 has an excellent ultraviolet shielding effect.

From the above results, it is clear that the square plate-like zinc oxide particle particles of the present invention are particles having good sliding properties and can be suitably used as a cosmetic material.

The square plate-like zinc oxide particles of the present invention can be suitably used in various applications such as cosmetics, resin compositions, coating compositions, and ink compositions.

Claims (10)

1. The ratio of the long side length to the short side length (long side length / short side length) is 1.00 to 1.30, and the long side length to thickness ratio (long side length) Square plate-like zinc oxide particles, wherein the / thickness is 3 to 100.
2. The square plate-like zinc oxide particles according to claim 1, wherein the length of the long side is 5 μm or more and 100 μm or less.
3. The rectangular plate-like zinc oxide particles according to claim 1 or 2, wherein the zinc oxide content is 85% by weight or more, and no heterogeneous phase is observed from the XRD pattern.
4. 4. The rectangular plate-like zinc oxide according to claim 1, comprising a step (1) of mixing raw material zinc oxide, zinc nitrate, and trivalent and / or tetravalent metal elements in a solvent. Particle production method.
5. 5. The method for producing rectangular plate-like zinc oxide particles according to claim 4, wherein a part or all of the trivalent and / or tetravalent metal element is present in the raw material zinc oxide.
6. The method for producing rectangular plate-like zinc oxide particles according to claim 4 or 5, wherein a part or all of the trivalent and / or tetravalent metal element is dissolved and / or dispersed in a solvent.
7. A cosmetic comprising the square plate-like zinc oxide particles according to any one of claims 1 to 3.
8. A resin composition comprising the square plate-like zinc oxide particles according to any one of claims 1 to 3.
9. A coating composition containing the square plate-like zinc oxide particles according to any one of claims 1 to 3.
10. An ink composition comprising the square plate-like zinc oxide particles according to any one of claims 1 to 3.

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