JP6682950B2 - Surface treated zinc oxide particles, dispersion, cosmetics and zinc oxide particles - Google Patents

Description

  The present invention relates to surface-treated zinc oxide particles, dispersions, cosmetics and zinc oxide particles.

  It is known that zinc oxide has an excellent ability to block ultraviolet rays, has a high gas barrier property, and has good transparency. Therefore, particles using zinc oxide as a forming material (hereinafter referred to as zinc oxide particles) are used as a forming material for various materials that have functions such as ultraviolet ray shielding and gas barrier and need transparency. Examples of such a material include an ultraviolet shielding film, an ultraviolet shielding glass, cosmetics, and a gas barrier film.

  One of the methods for obtaining transparency with respect to the various materials described above is to reduce the primary particle diameter of zinc oxide particles as a forming material. As a method for reducing the primary particle diameter of zinc oxide particles, various methods such as a thermal decomposition method and a vapor phase method have been studied (see, for example, Patent Documents 1 and 2).

  When applying zinc oxide particles to cosmetics, surface treatment of the zinc oxide particles is performed in order to match the surface of the zinc oxide particles to the properties of the cosmetic product and to suppress the catalytic activity of the zinc oxide particles. As the surface treatment agent for such zinc oxide particles, for example, a metal soap such as Mg stearate, a silicone oil such as dimethicone or hydrogen dimethicone, or a silane coupling agent having an alkoxy group such as octyltriethoxysilane is used. (See, for example, Patent Documents 3 and 4).

  Among them, the zinc oxide particles surface-treated with the silane coupling agent have high stability because the silane coupling agent as the surface treatment agent is chemically bonded to the surface of the zinc oxide particles. Furthermore, by using a surface treating agent having different substituents, the properties of the particle surface can be easily changed. In the following description, zinc oxide particles surface-treated with a silane coupling agent are referred to as surface-treated zinc oxide particles.

  Such surface-treated particles are blended into cosmetics as they are, or are blended into cosmetics in the form of a dispersion liquid dispersed in a dispersion medium.

JP-A-2002-284527 JP, 2000-95519, A JP, 2002-362925, A JP, 2001-181136, A

  However, the surface-treated particles sometimes have a poor UV-shielding property when blended in a cosmetic, and there is a problem that the quality is difficult to stabilize.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide surface-treated zinc oxide particles that stably exhibit high ultraviolet shielding properties. Moreover, it aims at providing together the dispersion liquid and cosmetics containing such surface-treated zinc oxide particles. Moreover, it aims at providing the zinc oxide particle which can manufacture such a surface treatment zinc oxide particle suitably.

In order to solve the above problems, one embodiment of the present invention is a surface-treated zinc oxide particle, wherein the particle surface of the zinc oxide particle is treated with a silane coupling agent having an alkoxy group, wherein the zinc oxide particle is: Provided are surface-treated zinc oxide particles satisfying formula (1).
S · M / σ ² ≧ 0.05 (1)
(S is the specific surface area of zinc oxide particles (unit: m ² / g), M is the Na content of zinc oxide particles (unit: mg / kg), σ is 10 parts by mass of zinc oxide particles and 90 parts by mass of pure water. Is the conductivity (unit: μS / cm) of the slurry obtained by mixing for 1 hour.)

In one aspect of the present invention, the specific surface area S may be 4 m ² / g or more and 35 m ² / g or less.

  In one aspect of the present invention, the silane coupling agent may be at least one selected from the group consisting of alkylalkoxysilane, allylalkoxysilane, and polysiloxane having an alkyl group or an allyl group in its side chain. .

  In one aspect of the present invention, the silane coupling agent may be at least one selected from the group consisting of octyltriethoxysilane, octyltrimethoxysilane, and dimethoxydiphenylsilane-triethoxycaprylylsilane crosspolymer. .

  In order to solve the above problems, one embodiment of the present invention provides a dispersion liquid containing the above surface-treated zinc oxide particles and a dispersion medium.

  In order to solve the above problems, one aspect of the present invention provides a cosmetic containing at least one selected from the group consisting of the surface-treated zinc oxide particles and the dispersion.

In order to solve the above problems, one embodiment of the present invention provides zinc oxide particles that satisfy the following formula (1).
S · M / σ ² ≧ 0.05 (1)
(S is the specific surface area of zinc oxide particles (unit: m ² / g), M is the Na content of zinc oxide particles (unit: mg / kg), σ is 10 parts by mass of zinc oxide particles and 90 parts by mass of pure water. Is the conductivity (unit: μS / cm) of the slurry obtained by mixing for 1 hour.)

In one aspect of the present invention, the specific surface area S may be 4 m ² / g or more and 35 m ² / g or less.

  According to the present invention, it is possible to provide surface-treated zinc oxide particles that stably exhibit high ultraviolet shielding properties. Further, according to the present invention, it is possible to provide a dispersion liquid and a cosmetic containing such surface-treated zinc oxide particles. Further, according to the present invention, it is possible to provide zinc oxide particles capable of suitably producing such surface-treated zinc oxide particles.

6 is a graph showing the relationship between S · M / σ ² and d50. 5 is a graph showing the relationship between S · M / σ ² and SPF value.

  Embodiments of the surface-treated zinc oxide particles, the dispersion, the cosmetic and the zinc oxide particles of the present invention will be described. It should be noted that the present embodiment is specifically described for better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified.

  In the following description, the surface-treated zinc oxide particles may be abbreviated as “surface-treated particles”.

[Zinc oxide particles]
The zinc oxide particles of this embodiment can be suitably used for producing the surface-treated particles of the present invention. The zinc oxide particles of this embodiment satisfy the following formula (1).
S · M / σ ² ≧ 0.05 (1)
(S is the specific surface area of zinc oxide particles (unit: m ² / g), M is the Na content of zinc oxide particles (unit: mg / kg), σ is 10 parts by mass of zinc oxide particles and 90 parts by mass of pure water. Is the conductivity (unit: μS / cm) of the slurry obtained by mixing for 1 hour.)

  In general, surface-treated particles obtained by surface-treating zinc oxide particles with a silane coupling agent having an alkoxy group (hereinafter referred to as a silane coupling agent) may be used by being mixed with a cosmetic material. However, the surface-treated particles using the conventional zinc oxide particles sometimes have a poor UV-shielding property when blended in cosmetics, and there is a problem that the quality is difficult to stabilize.

  The inventors of the present invention have earnestly studied the above problems, and found that when the zinc oxide particles contained a large amount of impurities, the cosmetic using the obtained surface-treated particles had a low UV-shielding property, and completed the present invention.

  That is, when zinc oxide particles satisfying the above formula (1) are used, the obtained surface-treated particles stably exhibit a high ultraviolet shielding property. Therefore, the zinc oxide particles of the present embodiment can be used for various purposes, but are particularly useful as a raw material for cosmetics. In addition, in this embodiment, an ultraviolet-shielding property shall be evaluated using a SPF (Sun Protection Factor) value.

  The specific surface area of the zinc oxide particles of the present embodiment means a value measured by the BET method using a fully automatic specific surface area measuring device (trade name: Macsorb HM Model-1201, manufactured by Mountech Co., Ltd.).

  The Na content of the zinc oxide particles of the present embodiment means a value measured by a polarized Zeeman atomic absorption altimeter (model number: Z-2000, manufactured by Hitachi High-Tech Co., Ltd.). The measurement is performed using a solution in which zinc oxide particles are placed in a Teflon (registered trademark) beaker, an appropriate amount of water and 5 ml of nitric acid are added, and the mixture is heated and dissolved.

  The electrical conductivity of a slurry obtained by mixing 10 parts by mass of zinc oxide particles of the present embodiment with 90 parts by mass of pure water for 1 hour (hereinafter referred to as slurry conductivity) means a value measured by the following method. The measurement is performed by mixing 10 parts by mass of zinc oxide particles and 90 parts by mass of pure water for 1 hour, and using a conductivity meter (trade name: ES-12, manufactured by Horiba, Ltd.) for the obtained slurry.

The specific surface area of the zinc oxide particles of the present embodiment is preferably 4 m ² / g or more, more preferably 6 m ² / g or more, further preferably 8 m ² / g or more, and 9 m ² / g. More preferably, it is more preferably 10 m ² / g or more, particularly preferably 20 m ² / g or more. Moreover, the specific surface area of the zinc oxide particles is preferably 35 m ² / g or less, more preferably 33 m ² / g or less, and further preferably 31 m ² / g or less. The upper limit value and the lower limit value of the specific surface area of the zinc oxide particles can be arbitrarily combined.

  When the specific surface area of the zinc oxide particles is within the above range, a cosmetic material having higher transparency can be obtained when formulated into a cosmetic material, which is preferable.

  The Na content of the zinc oxide particles of the present embodiment is preferably 10 mg / kg or more, more preferably 20 mg / kg or more, and further preferably 50 mg / kg or more. In addition, the Na content of the zinc oxide particles is preferably 500 mg / kg or less, more preferably 200 mg / kg or less, and further preferably 100 mg / kg or less. The upper limit value and the lower limit value of the Na content of the zinc oxide particles can be arbitrarily combined.

  When the Na content of the zinc oxide particles is within the above range, the uniformity and homogeneity of the surface treatment reaction with the silane coupling agent becomes good, the dispersibility is high, and the surface treated particles having excellent ultraviolet shielding performance are obtained. You can

  The slurry conductivity of the zinc oxide particles of the present embodiment is preferably 25 μS / cm or more, more preferably 30 μS / cm or more, and further preferably 50 μS / cm or more. Moreover, the slurry conductivity of the zinc oxide particles is preferably 200 μS / cm or less, more preferably 150 μS / cm or less, and further preferably 100 μS / cm or less. The upper limit value and the lower limit value of the slurry conductivity of the zinc oxide particles can be arbitrarily combined.

  When the slurry conductivity of the zinc oxide particles is within the above range, the uniformity and homogeneity of the surface treatment reaction with the silane coupling agent becomes good, the dispersibility is high, and the surface treated particles having excellent ultraviolet shielding performance are obtained. You can

From the viewpoint of further improving the SPF value, the left side (S · M / σ ² ) of the above formula (1) is preferably 0.10 or more, more preferably 0.20 or more, and 0. It is more preferably 30 or more.

The upper limit of S · M / σ ² is not particularly limited. For example, it may be 1.0 or less, 0.80 or less, 0.60 or less, or 0.50 or less.

The upper limit value and the lower limit value of S · M / σ ² can be arbitrarily combined.

  Furthermore, when the zinc oxide particles of the present embodiment are surface-treated with a silane coupling agent, the slurry obtained by mixing 10 parts by mass of the zinc oxide particles and 90 parts by mass of pure water for 1 hour has a pH of 7.1 or more and It is preferably 9.0 or less, more preferably 7.5 or more and 9.0 or less, and further preferably 7.5 or more and 8.5 or less.

  The pH of the slurry prepared by mixing 10 parts by mass of zinc oxide particles of the present embodiment and 90 parts by mass of pure water for 1 hour means a value measured by the following method. The measurement is performed by mixing 10 parts by mass of zinc oxide particles and 90 parts by mass of pure water for 1 hour, and using a pH meter (trade name: D-51, manufactured by Horiba, Ltd.) for the obtained slurry.

  The surface treatment reaction of the silane coupling agent is a hydrolysis / polycondensation reaction, and it is preferable that the hydrolyzed silane coupling agent reacts rapidly with the zinc oxide particles in terms of reaction efficiency of the surface coating. When the pH of the zinc oxide particles is in the above range, the rate of hydrolysis reaction and polycondensation reaction when surface-treating the zinc oxide particles with a silane coupling agent is well balanced, and the silane coupling agent is zinc oxide. It is preferable because the surface of the particles is easily treated uniformly. It is also preferable in that it is possible to suppress the dissolution of the zinc oxide particles during the surface treatment.

  By surface-treating zinc oxide particles having a pH in the above range with a silane coupling agent, the surface treatment reaction will have good homogeneity and homogeneity, high dispersibility, and surface-treated particles having excellent ultraviolet shielding performance will be obtained. You can

  The method for producing the zinc oxide particles of the present embodiment is not particularly limited, but the zinc oxide particles can be produced by the known methods of Patent Documents 1 and 2.

  For example, it is produced by adding a solution of sodium carbonate or sodium hydroxide to an aqueous solution of zinc sulfate to form a precipitate such as basic zinc carbonate, zinc carbonate or zinc hydroxide, which is washed with water, dried, calcined and crushed. be able to. At this time, the specific surface area of the zinc oxide particles can be adjusted by changing the calcination temperature and the calcination time. In addition, the Na content, conductivity, and pH of the zinc oxide particles can be adjusted by adjusting the end point of washing the precipitate with water or washing the obtained zinc oxide particles again.

[Surface treated zinc oxide particles]
The surface-treated zinc oxide particles of the present embodiment are surface-treated zinc oxide particles whose surface is treated with a silane coupling agent having an alkoxy group, and the zinc oxide particles have the following formula (1): Fulfill.
S · M / σ ² ≧ 0.05 (1)
(S is the specific surface area of zinc oxide particles (unit: m ² / g), M is the Na content of zinc oxide particles (unit: mg / kg), σ is 10 parts by mass of zinc oxide particles and 90 parts by mass of pure water. Is the conductivity (unit: μS / cm) of the slurry obtained by mixing for 1 hour.)

  That is, the surface-treated particles of this embodiment are obtained by surface-treating the zinc oxide particles of this embodiment with a silane coupling agent.

  In the surface-treated particles of the present embodiment, the preferable range is about the specific surface area of the zinc oxide particles contained, the Na content, and the conductivity of the slurry in which 10 parts by mass of the zinc oxide particles and 90 parts by mass of pure water are mixed for 1 hour. The same numerical range as that of the zinc oxide particles described above can be adopted.

  The surface-treated particles obtained by treating the surface of the zinc oxide particles with the silane coupling agent have very high stability because the silane coupling agent and the zinc oxide particles are chemically bonded. Further, the properties of the particle surface can be easily changed by using silane coupling agents having different substituents. For example, by changing the type of the silane coupling agent, the cosmetics containing the surface-treated particles of the present embodiment has an advantage that it is possible to change the feel such as elongation and texture when applied to the skin. .

When the surface-treated particles of the present embodiment are mixed in a cosmetic, the silane coupling agent used for the surface treatment is not particularly limited as long as it is a silane coupling agent that can be used in the cosmetic.
For example, as the silane coupling agent, among the silane coupling agents represented by the general formula (2), those usable in cosmetics can be mentioned.
R ¹ Si (OR ² ) ₃ (2)
(R ¹ represents an alkyl group having 1 to 18 carbon atoms, a fluoroalkyl group or a phenyl group, and R ² represents an alkyl group having 1 to 4 carbon atoms)

Specifically, as a silane coupling agent used for surface treatment,
Methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, ethyltributoxysilane, n-propyltrimethoxysilane, n-propyl Triethoxysilane, n-propyltripropoxysilane, n-propyltributoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, isopropyltripropoxysilane, isopropyltributoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltri Propoxysilane, phenyltributoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane (triethoxycap Rirushiran), alkoxysilanes such as n- octadecyl trimethoxysilane;
Fluoroalkoxysilanes such as trifluoropropyltrimethoxysilane, perfluorooctyltriethoxysilane and tridecafluorooctyltriethoxysilane, fluoroalkylalkoxysilanes;
Is mentioned.

  Further, as a silane coupling agent used for surface treatment, a main chain of siloxane skeleton such as dimethoxydiphenylsilane-triethoxycaprylylsilane crosspolymer, triethoxysilylethylpolydimethylsiloxyethyldimethicone, triethoxysilylethylpolydimethylsiloxyethylhexyldimethicone. And a polymer type silane coupling agent having an alkoxy group and an acrylic group in the molecular structure.

  These silane coupling agents may be used alone or in combination of two or more.

Among the above silane coupling agents, a silane coupling agent having an octyl group in the molecule is preferable. Specifically, octyltriethoxysilane, octyltrimethoxysilane, and dimethoxydiphenylsilane-triethoxycaprylic, which have moderate polarity of functional groups and can be used in a wide range of polar oil phases from natural oils and ester oils to silicone oils. Rylsilane crosspolymer can be used particularly preferably.
These silane coupling agents may be used alone or in combination of two or more.

  The surface treatment amount of the silane coupling agent may be appropriately adjusted according to desired characteristics, but is preferably 2% by mass or more and 10% by mass or less with respect to the content of zinc oxide particles. By subjecting the zinc oxide particles to the surface treatment with a silane coupling agent in the above range, it is easy to obtain surface-treated particles having excellent dispersibility and ultraviolet shielding properties, which is preferable.

  In addition to the silane coupling agent, a surface treatment agent used in cosmetics other than the silane coupling agent is used as long as it does not impair the characteristics of the surface-treated particles of the present embodiment. The particles may be surface treated.

  As the surface treatment agent other than the silane coupling agent, for example, inorganic materials such as silica and alumina, and organic materials such as silicone compounds, fatty acids, fatty acid soaps, fatty acid esters and organic titanate compounds can be used.

  The method for producing the surface-treated particles of the present embodiment is not particularly limited, and may be appropriately performed by a known method such as dry treatment or wet treatment depending on the components used for the surface treatment.

  For example, in the case of dry treatment, while stirring the zinc oxide particles in a mixer such as a Henschel mixer or a super mixer, the silane coupling agent is added under the liquid droplets or by spray spraying, and then vigorously stirred for a certain period at high speed. After that, the surface treatment may be performed by heating at 70 ° C. to 200 ° C. while continuing stirring.

  Water for the hydrolysis of the silane coupling agent may be water attached to the zinc oxide particles, and may be added together with the silane coupling agent or separately as necessary.

  The silane coupling agent may be diluted with a solvent that can be mixed with the silane coupling agent. Examples of such a solvent include alcohols such as methanol, ethanol and isopropanol, and n-hexane, toluene and xylene. When water is added for surface treatment, a polar solvent such as alcohol having a high compatibility with water is preferably used among these solvents.

  For example, in the case of wet treatment, zinc oxide particles, a silane coupling agent, and a solvent are stirred and mixed at 25 ° C. to 100 ° C. for several hours, solid-liquid separated, and washed. There may be mentioned a method of performing surface treatment by heat treatment at ℃. Water for the hydrolysis of the silane coupling agent may be water attached to the zinc oxide particles, and may be added together with the silane coupling agent or separately as necessary.

  The silane coupling agent may be diluted with a solvent that can be mixed with the silane coupling agent. Examples of such a solvent include alcohols such as methanol, ethanol and isopropanol, and n-hexane, toluene and xylene. When water is added for surface treatment, a polar solvent such as alcohol having a high compatibility with water is preferably used among these solvents.

[Dispersion]
The dispersion liquid of the present embodiment contains the surface-treated particles of the present embodiment and a dispersion medium.
The dispersion of the present embodiment also includes a paste-like dispersion having a high viscosity.

The dispersion medium is not particularly limited as long as it can be formulated into cosmetics and can disperse the surface-treated particles.
For example, water;
Alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, octanol and glycerin;
Esters such as ethyl acetate, butyl acetate, ethyl lactate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate and γ-butyrolactone;
Ethers such as 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;
Natural oil, ester oil, silicone oil and the like are preferably used.
These dispersion media may be used alone or in combination of two or more.

Other dispersion media include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, and cyclohexanone;
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene;
Cyclic hydrocarbons such as cyclohexane;
Amides such as dimethylformamide, N, N-dimethylacetoacetamide and N-methylpyrrolidone;
Chain polysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane and diphenylpolysiloxane are used.
These dispersion media may be used alone or in combination of two or more.

Further, other dispersion mediums include cyclic polysiloxanes such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexanesiloxane;
Modified polysiloxanes such as amino-modified polysiloxane, polyether-modified polysiloxane, alkyl-modified polysiloxane, and fluorine-modified polysiloxane are used.
These dispersion media may be used alone or in combination of two or more.

Other dispersion media include hydrocarbon oils such as liquid paraffin, squalane, isoparaffin, branched light paraffin, petrolatum and ceresin;
Ester oils such as isopropyl myristate, cetyl isooctanoate, glyceryl trioctanoate;
Silicone oils such as decamethylcyclopentasiloxane, dimethylpolysiloxane, methylphenylpolysiloxane;
Higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid;
A hydrophobic dispersion medium such as higher alcohols such as lauryl alcohol, cetyl alcohol, stearyl alcohol, hexyldecanol, and isostearyl alcohol may be used.

  The dispersion liquid of the present embodiment may contain commonly used additives as long as the characteristics are not impaired.

  Examples of the additive include other components such as preservatives, dispersants, dispersion aids, stabilizers, water-soluble binders, thickeners, oil-soluble drugs, oil-soluble dyes, oil-soluble proteins, and UV absorbers. May be included.

  The particle size (d50) when the cumulative volume percentage of the particle size distribution in the dispersion liquid of the present embodiment is 50% is preferably 300 nm or less, more preferably 250 nm or less, and further preferably 200 nm or less. preferable.

  The lower limit of d50 is not particularly limited, and may be, for example, 50 nm or more, 100 nm or more, and 150 nm or more. The upper limit value and the lower limit value of d50 can be arbitrarily combined.

  Further, the particle size (d90) when the cumulative volume percentage of the particle size distribution in the dispersion liquid of the present embodiment is 90% is preferably 400 nm or less, more preferably 350 nm or less, and more preferably 300 nm or less. More preferable.

  The lower limit value of d90 is not particularly limited, and may be, for example, 100 nm or more, 150 nm or more, and 200 nm or more. The upper limit and the lower limit of d90 can be arbitrarily combined.

  When the d50 of the dispersion is 300 nm or less, the surface-treated particles are likely to be uniformly distributed and the ultraviolet light shielding effect is improved when the cosmetic prepared using this dispersion is applied to the skin, which is preferable. When the d90 of the dispersion is 400 nm or less, the transparency of the dispersion is high, and the transparency of the cosmetic prepared using this dispersion is also high, which is preferable.

  That is, when the d50 and d90 of the dispersion liquid in the present embodiment are in the above ranges, it is possible to obtain a dispersion liquid which is excellent in transparency and ultraviolet shielding property. In addition, cosmetics produced using this dispersion are also excellent in transparency and ultraviolet shielding properties.

  The content of zinc oxide particles in the dispersion liquid of the present embodiment may be appropriately adjusted according to desired characteristics.

  When the dispersion of the present embodiment is used for cosmetics, the content of zinc oxide particles in the dispersion is preferably 30% by mass or more, more preferably 40% by mass or more, and 50% by mass. It is more preferable that the above is satisfied. Further, the content of zinc oxide particles in the dispersion is preferably 90% by mass or less, more preferably 85% by mass or less, and further preferably 80% by mass or less. The upper limit value and the lower limit value of the content of zinc oxide particles in the dispersion liquid can be arbitrarily combined.

  When the content of the zinc oxide particles in the dispersion is in the above range, the zinc oxide particles are contained in a high concentration, so that the degree of freedom in prescription can be improved and the viscosity of the dispersion can be easily handled. It can be a degree.

  The viscosity of the dispersion liquid of the present embodiment is preferably 5 Pa · s or more, more preferably 8 Pa · s or more, further preferably 10 Pa · s or more, and 15 Pa · s or more. Most preferred. Further, the viscosity of the dispersion liquid is preferably 300 Pa · s or less, more preferably 100 Pa · s or less, further preferably 80 Pa · s or less, and most preferably 60 Pa · s or less. . The upper and lower limits of the viscosity of the dispersion can be arbitrarily combined.

  When the viscosity of the dispersion liquid is within the above range, it is possible to obtain a dispersion liquid that is easy to handle even if the solid content (zinc oxide particles) is contained in a high concentration.

The dispersion liquid of the present embodiment is measured when the dispersion liquid containing 10% by mass of the surface-treated particles is applied to have a thickness of 12 μm and naturally dried for 15 minutes to form a coating film. The physical property values are preferably in the following ranges.
That is, the transmittance of the coating film at 450 nm is preferably 40% or more, more preferably 45% or more, and even more preferably 50% or more. The upper limit value is not particularly limited, and may be 100% or less, 90% or less, or 80% or less. The upper limit and the lower limit of the transmittance at 450 nm of the coating film can be arbitrarily combined.

  The higher the transmittance of the coating film at 450 nm is, the more excellent the transparency is. Therefore, the higher transmittance at 450 nm is preferable.

  The average transmittance of the coating film at 290 nm to 320 nm is preferably 10% or less, more preferably 7% or less, and further preferably 5% or less. The lower limit value is not particularly limited, and may be 0%, 0.5%, or 1%. The upper limit value and the lower limit value of the average transmittance of the coating film at 290 nm to 320 nm can be arbitrarily combined.

  The smaller the average transmittance at 290 nm to 320 nm of the coating film is, the more excellent the ultraviolet shielding property is. Therefore, it is preferable that the average transmittance at 290 nm to 320 nm is small.

  The SPF value of the coating film is preferably 30 or more, more preferably 35 or more, and further preferably 40 or more. The upper limit value is not particularly limited, and may be 150, 100, or 80. The upper and lower limits of the SPF value of the coating film can be arbitrarily combined.

  The larger the SPF value of the coating film, the greater the effect of preventing ultraviolet B waves, and therefore the larger the SPF value is.

  The critical wavelength (Critical Wavelength) of the coating film is preferably 370 nm or more. Since the critical wavelength of the dispersion liquid is 370 nm or more, the cosmetic material containing this dispersion liquid has a critical wavelength of 370 nm or more, and shields a wide range of ultraviolet rays of long wavelength ultraviolet rays (UVA) and short wavelength ultraviolet rays (UVB). be able to.

  In the present specification, the “critical wavelength” is a value obtained by measuring a coating film coated with the dispersion liquid. Specifically, when the absorption spectrum of the coating film in the ultraviolet region of 290 nm or more and 400 nm or less is measured and integrated in the obtained absorption spectrum from 290 nm to the long wavelength side, the total area of the integrated area of 290 nm or more and 400 nm or less The wavelength at which 90% of the integrated area at is obtained is the "critical wavelength" to be obtained.

  The method for producing the dispersion liquid of the present embodiment is not particularly limited. For example, a method of mechanically dispersing the surface-treated particles of this embodiment and a dispersion medium with a known dispersing device can be mentioned.

  The dispersing device can be selected as necessary, and examples thereof include a stirrer, a revolving mixer, a homomixer, an ultrasonic homogenizer, a sand mill, a ball mill, and a roll mill.

  The dispersion liquid of the present embodiment can be used for not only cosmetics but also paints having an ultraviolet shielding function, a gas permeation suppressing function, and the like.

[Composition]
The composition of the present embodiment contains the surface-treated particles of the present embodiment, a resin, and a dispersion medium.

  The content of the surface-treated particles in the composition of the present embodiment may be appropriately adjusted according to desired characteristics, but is preferably 10% by mass or more and 40% by mass or less, and 20% by mass or more and It is preferably 30% by mass or less.

  When the content of the surface-treated particles in the composition is within the above range, the solid content (zinc oxide particles) is contained in a high concentration, so that the characteristics of the surface-treated particles can be sufficiently obtained, and the surface-treated particles can be made uniform. A dispersed composition can be obtained.

  The dispersion medium is not particularly limited as long as it is one commonly used in industrial applications, for example, water, alcohols such as methanol, ethanol, propanol, methyl acetate, ethyl acetate, toluene, methyl ethyl ketone, methyl isobutyl ketone, etc. Is mentioned.

  The content of the dispersion medium in the composition of the present embodiment is not particularly limited and is appropriately adjusted according to the characteristics of the intended composition.

  The resin is not particularly limited as long as it is one that is generally used in industrial applications, and examples thereof include acrylic resin, epoxy resin, urethane resin, polyester resin, and silicone resin.

  The content of the resin in the composition of the present embodiment is not particularly limited and is appropriately adjusted according to the characteristics of the intended composition.

The composition of the present embodiment may contain a commonly used additive as long as its properties are not impaired.
Examples of the additive include a polymerization initiator, a dispersant, a preservative, and the like.

  The method for producing the composition of the present embodiment is not particularly limited, and examples thereof include a method of mechanically mixing the surface-treated particles of the present embodiment, a resin, and a dispersion medium with a known mixing device. .

  Further, a method of mechanically mixing the above-mentioned dispersion liquid and the resin with a known mixing device can be mentioned.

  Examples of the mixing device include a stirrer, a revolving mixer, a homomixer, and an ultrasonic homogenizer.

  Application of the composition of the present embodiment to a plastic substrate such as a polyester film by a usual application method such as a roll coating method, a flow coating method, a spray coating method, a screen printing method, a brush coating method and a dipping method. By this, a coating film can be formed. These coating films can be used as an ultraviolet shielding film or a gas barrier film.

[Cosmetics]
The cosmetic of one embodiment of the present embodiment contains at least one selected from the group consisting of the surface-treated particles of the present embodiment and the dispersion of the present embodiment.

  The cosmetic of another embodiment comprises a cosmetic base material and at least one selected from the group consisting of the surface-treated particles of this embodiment and the dispersion of this embodiment.

Here, the cosmetic base material means various raw materials forming the main body of cosmetics, and examples thereof include oily 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, thickener and the like.

  Examples of powder raw materials include colored pigments, white pigments, pearlescent agents, and extender pigments.

  The cosmetic of the present embodiment can be obtained, for example, by conventionally mixing the dispersion of the present embodiment with a cosmetic base material such as an emulsion, a cream, a foundation, a lipstick, a blusher, and an eye shadow.

  In the cosmetic of the present embodiment, the surface-treated particles of the present embodiment are blended in an oil phase or an aqueous phase to prepare an O / W type or W / O type emulsion, and then blended with a cosmetic base material. Is obtained by

  The content of the surface-treated particles in the cosmetic may be appropriately adjusted according to desired characteristics. For example, the lower limit of the content of the surface-treated particles may be 0.01% by mass or more, and 0.1% by mass. %, Or 1% by mass or more. The upper limit of the content of the surface-treated particles may be 50% by mass or less, 40% by mass or less, or 30% by mass or less. The upper limit and the lower limit of the content of the surface-treated particles in the cosmetic can be arbitrarily combined.

Hereinafter, the sunscreen cosmetics will be specifically described.
In order to effectively shield ultraviolet rays, particularly long-wavelength ultraviolet rays (UVA), and to obtain a good feeling of use with less powdery or squeaky, the lower limit of the content of the surface-treated particles in the sunscreen cosmetic is 0. The amount is preferably 01% by mass or more, more preferably 0.1% by mass or more, and further preferably 1% by mass or more. Further, the upper limit of the content of the surface-treated particles in the sunscreen cosmetic may be 50% by mass or less, 40% by mass or less, or 30% by mass or less. The upper limit and the lower limit of the content of the surface-treated particles in the sunscreen cosmetics can be arbitrarily combined.

  Sunscreen cosmetics include hydrophobic dispersion medium, inorganic fine particles other than surface-treated particles and inorganic pigments, hydrophilic dispersion medium, oils and fats, surfactants, humectants, thickeners, pH adjusters, nutrition, as necessary. It may contain agents, antioxidants, fragrances and the like.

  Examples of the hydrophobic dispersion medium include hydrocarbon oils such as liquid paraffin, squalane, isoparaffin, branched light paraffin, petrolatum and ceresin, ester oils such as isopropyl myristate, cetyl isooctanoate and glyceryl trioctanoate. , Silicone oils such as decamethylcyclopentasiloxane, dimethylpolysiloxane, methylphenylpolysiloxane, higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, lauryl alcohol, cetyl alcohol, stearyl alcohol, hexyldecanol, iso Examples thereof include higher alcohols such as stearyl alcohol.

  Examples of the inorganic fine particles and inorganic pigments other than the surface-treated particles included in the cosmetics include calcium carbonate, calcium phosphate (apatite), magnesium carbonate, calcium silicate, magnesium silicate, aluminum silicate, kaolin, talc, titanium oxide, Examples thereof include aluminum oxide, yellow iron oxide, γ-iron oxide, cobalt titanate, cobalt violet and silicon oxide.

  The sunscreen cosmetic may further contain at least one organic ultraviolet absorber.

  Examples of organic UV absorbers include benzotriazole UV absorbers, benzoylmethane UV absorbers, benzoic acid UV absorbers, anthranilic acid UV absorbers, salicylic acid UV absorbers, and cinnamic acid UV absorbers. Agents, silicone-based cinnamic acid ultraviolet absorbers, organic ultraviolet absorbers other than these, and the like.

  Examples of the benzotriazole-based ultraviolet absorber include 2,2'-hydroxy-5-methylphenylbenzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole, 2- (2'-. Hydroxy-5'-methylphenyl benzotriazole etc. are mentioned.

  Examples of the benzoylmethane-based ultraviolet absorber include dibenzalazine, dianisoylmethane, 4-tert-butyl-4′-methoxydibenzoylmethane, 1- (4′-isopropylphenyl) -3-phenylpropane-1,3- Dione, 5- (3,3′-dimethyl-2-norbornylidene) -3-pentan-2-one and the like can be mentioned.

  Examples of the benzoic acid-based ultraviolet absorber include para-aminobenzoic acid (PABA), PABA monoglycerin ester, N, N-dipropoxy PABA ethyl ester, N, N-diethoxy PABA ethyl ester, N, N-dimethyl PABA ethyl ester, Examples thereof include N, N-dimethyl PABA butyl ester and N, N-dimethyl PABA methyl ester.

  Examples of the anthranilic acid-based ultraviolet absorber include homomenthyl-N-acetylanthranilate and the like.

  Examples of the salicylic acid-based ultraviolet absorber include amyl salicylate, menthyl salicylate, homomenthyl salicylate, octyl salicylate, phenyl salicylate, benzyl salicylate, p-2-propanolphenyl salicylate, and the like.

  Examples of the cinnamic acid-based ultraviolet absorber include octyl methoxycinnamate (ethylhexyl methoxycinnamate), di-paramethoxycinnamic acid-glyceryl mono-2-ethylhexanoate, octyl cinnamate, and ethyl-4-isopropyl cinnamate. Mate, methyl-2,5-diisopropylcinnamate, ethyl-2,4-diisopropylcinnamate, methyl-2,4-diisopropylcinnamate, propyl-p-methoxycinnamate, isopropyl-p-methoxycinnamate, isoamyl- p-methoxycinnamate, octyl-p-methoxycinnamate (2-ethylhexyl-p-methoxycinnamate), 2-ethoxyethyl-p-methoxycinnamate, cyclohexyl-p-methoxycinnamate, ethyl-α-cyano- β -Phenylcinnamate, 2-ethylhexyl-α-cyano-β-phenylcinnamate, glyceryl mono-2-ethylhexanoyl-diparamethoxycinnamate and the like can be mentioned.

  Examples of the silicone-based cinnamic acid ultraviolet absorber include [3-bis (trimethylsiloxy) methylsilyl-1-methylpropyl] -3,4,5-trimethoxycinnamate and [3-bis (trimethylsiloxy) methylsilyl- 3-Methylpropyl] -3,4,5-trimethoxycinnamate, [3-bis (trimethylsiloxy) methylsilylpropyl] -3,4,5-trimethoxycinnamate, [3-bis (trimethylsiloxy) methyl Silylbutyl] -3,4,5-trimethoxycinnamate, [3-tris (trimethylsiloxy) silylbutyl] -3,4,5-trimethoxycinnamate, [3-tris (trimethylsiloxy) silyl-1-methyl Propyl] -3,4-dimethoxycinnamate and the like.

  Examples of organic ultraviolet absorbers other than the above include, for example, 3- (4′-methylbenzylidene) -d, l-camphor, 3-benzylidene-d, l-camphor, urocanic acid, urocanic acid ethyl ester, and 2-phenyl. Examples include -5-methylbenzoxazole, 5- (3,3'-dimethyl-2-norbornylidene) -3-pentan-2-one, a silicone-modified ultraviolet absorber, and a fluorine-modified ultraviolet absorber.

  The critical wavelength of the cosmetic material of the present embodiment is preferably 370 nm or more. When the critical wavelength of the cosmetic is 370 nm or more, a wide range of long-wave ultraviolet (UVA) and short-wave ultraviolet (UVB) ultraviolet can be blocked.

The surface-treated zinc oxide particles as described above stably exhibit a high ultraviolet shielding property.
Further, according to the dispersion liquid and the cosmetic material as described above, since the surface-treated zinc oxide particles as described above are contained, it is possible to stably exhibit a high ultraviolet ray shielding property.
Moreover, according to the zinc oxide particles as described above, the surface-treated zinc oxide particles as described above can be preferably produced.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

  The zinc oxide particles of Examples 1 to 5 and Comparative Examples 1 and 2 were produced by changing the number of times the slurry containing the zinc oxide particles was washed with pure water when the zinc oxide particles were manufactured by the wet method.

[Example 1]
"Preparation of surface-treated particles"
Zinc oxide particles A1 (specific surface area S: 30 m ² / g, Na content M: 56 mg / kg, conductivity σ of a 10 mass% slurry stirred in pure water for 1 hour (hereinafter, “slurry conductivity σ”): 100 parts by mass of 85.6 μS / cm and S · M / σ ² = 0.23) were charged into a Henschel mixer. While stirring and mixing the zinc oxide particles A1, a mixed solution of 5 parts by mass of octyltriethoxysilane (KBE-3083 manufactured by Shin-Etsu Chemical Co., Ltd.), 0.375 parts by mass of pure water, and 7.125 parts by mass of isopropyl alcohol was mixed. Add and mix in a Henschel mixer and stir for 1 hour.

  Then, the obtained mixture was pulverized with a jet mill, and the pulverized powder was dried at 100 ° C. to obtain surface-treated particles B1 of Example 1.

"Preparation of dispersion"
10 parts by mass of the surface-treated particles B1, 2 parts by mass of a dispersant (KF-6028 manufactured by Shin-Etsu Chemical Co., Ltd.), and 88 parts by mass of decamethylcyclopentasiloxane were stirred at 4000 rpm using a stirrer, Dispersion C1 of 1 was obtained.

[Example 2]
Instead of using zinc oxide particles A1, zinc oxide particles A2 (specific surface area S: 30 m ² / g, Na content M: 70 mg / kg, slurry conductivity σ: 186.7 μS / cm, S · M / σ ² = In the same manner as in Example 1 except that (0.06) was used, surface-treated particles B2 and dispersion C2 of Example 2 were obtained.

[Example 3]
Instead of using zinc oxide particles A1, zinc oxide particles A3 (specific surface area S: 24 m ² / g, Na content M: 81 mg / kg, slurry conductivity σ: 67.1 μS / cm, S · M / σ ² = The surface-treated particles B3 and the dispersion C3 of Example 3 were obtained in the same manner as in Example 1 except that 0.43) was used.

[Example 4]
Instead of using zinc oxide particles A1, zinc oxide particles A4 (specific surface area S: 24 m ² / g, Na content M: 97 mg / kg, slurry conductivity σ: 75.7 μS / cm, S · M / σ ² = The surface-treated particles B4 and the dispersion C4 of Example 4 were obtained in the same manner as in Example 1 except that 0.41) was used.

[Example 5]
Instead of using zinc oxide particles A1, zinc oxide particles A5 (specific surface area S: 20 m ² / g, Na content M: 101 mg / kg, slurry conductivity σ: 81.2 μS / cm, S · M / σ ² = In the same manner as in Example 1 except that 0.31) was used, surface-treated particles B5 and dispersion C5 of Example 5 were obtained.

[Example 6]
Instead of using zinc oxide particles A1, zinc oxide particles A6 (specific surface area S: 10 m ² / g, Na content M: 31 mg / kg, slurry conductivity σ: 82.0 μS / cm, S · M / σ ² = The surface-treated particles B6 and the dispersion C6 of Example 6 were obtained in the same manner as in Example 1 except that 0.05) was used.

[Example 7]
Instead of using zinc oxide particles A1, zinc oxide particles A7 (specific surface area S: 15 m ² / g, Na content M: 48 mg / kg, slurry conductivity σ: 65.0 μS / cm, S · M / σ ² = The surface-treated particles B7 and the dispersion C7 of Example 7 were obtained in the same manner as in Example 1 except that 0.17) was used.

[Comparative Example 1]
Instead of using zinc oxide particles A1, zinc oxide particles A8 (specific surface area S: 30 m ² / g, Na content M: 1400 mg / kg, slurry conductivity σ: 1034 μS / cm, S · M / σ ² = 0. 04) was used in the same manner as in Example 1 to obtain surface-treated particles B8 and dispersion C8 of Comparative Example 1.

[Comparative Example 2]
Instead of using zinc oxide particles A1, zinc oxide particles A9 (specific surface area S: 24 m ² / g, Na content M: 2400 mg / kg, slurry conductivity σ: 1370 μS / cm, S · M / σ ² = 0. In the same manner as in Example 1 except that 03) was used, surface-treated particles B9 and dispersion C9 of Comparative Example 2 were obtained.

[Comparative Example 3]
Instead of using zinc oxide particles A1, zinc oxide particles A10 (specific surface area S: 8 m ² / g, Na content M: 18 mg / kg, slurry conductivity σ: 76.2 μS / cm, S · M / σ ² = In the same manner as in Example 1 except that (0.02) was used, surface-treated particles B10 and dispersion C10 of Comparative Example 2 were obtained.

"Evaluation"
(Measurement of particle size distribution)
The dispersions obtained in Examples 1 to 7 and Comparative Examples 1 to 3 were measured using a dynamic light scattering particle size distribution measuring device (model number: LB-550, manufactured by Horiba Ltd.), and the cumulative volume percentage was The particle size (d50) at 50% and the particle size (d90) at a cumulative volume percentage of 90% were determined.

(Measurement of SPF value, critical wavelength, transmittance)
The dispersions obtained in Examples 1 to 7 and Comparative Examples 1 to 3 were each applied on a quartz glass plate so as to have a thickness of 12 μm, and naturally dried for 15 minutes to form a coating film.

  The obtained coating film was measured using an SPF analyzer UV-1000S (manufactured by Labsphere), and the spectral transmittance in the ultraviolet region (average transmittance at 290 to 320 nm, transmittance at 450 nm), SPF value, and critical wavelength were determined. I asked.

  Table 1 shows the zinc oxide particles used in Examples 1 to 7 and Comparative Examples 1 to 3. Table 2 shows the evaluation results of Examples 1 to 7 and Comparative Examples 1 to 3.

FIG. 1 is a graph showing the relationship between S · M / σ ² and d50 for Examples 1 to 7 and Comparative Examples 1 to 3. FIG. 2 is a graph showing the relationship between S · M / σ ² and SPF value for Examples 1 to 7 and Comparative Examples 1 to 3. From FIGS. 1 and 2, if S · M / σ ² is 0.05 or more, a dispersion liquid having a d50 of 300 nm or less and excellent in dispersibility and having an SPF value of 30 or more and excellent in ultraviolet shielding property can be obtained. confirmed.

  From the above results, it was found that the present invention is useful.

  The surface-treated zinc oxide particles of the present invention stably show a high ultraviolet ray shielding property. Therefore, the surface-treated zinc oxide particles of the present invention are easy to ensure design quality when applied to dispersions, paints, and cosmetics, and their industrial value is great.

Claims (7)

A surface-treated zinc oxide particle, wherein the particle surface of the zinc oxide particle is treated with a silane coupling agent having an alkoxy group,
The zinc oxide particles meet the following expression (1),
Surface-treated zinc oxide particles having a Na content M in the following formula (1) of 20 mg / kg or more and 200 mg / kg or less .
S · M / σ ² ≧ 0.05 (1)
(S is the specific surface area of zinc oxide particles (unit: m ² / g), M is the Na content of zinc oxide particles (unit: mg / kg), σ is 10 parts by mass of zinc oxide particles and 90 parts by mass of pure water. Is the conductivity (unit: μS / cm) of the slurry obtained by mixing for 1 hour.) The surface-treated zinc oxide particles according to claim 1, wherein the specific surface area S is 4 m ² / g or more and 35 m ² / g or less.   The surface-treated zinc oxide according to claim 1 or 2, wherein the silane coupling agent is at least one selected from the group consisting of alkylalkoxysilanes, allylalkoxysilanes, and polysiloxanes having an alkyl group or an allyl group in the side chain. particle.   The surface-treated zinc oxide particles according to claim 3, wherein the silane coupling agent is at least one selected from the group of octyltriethoxysilane, octyltrimethoxysilane, and dimethoxydiphenylsilane-triethoxycaprylylsilane crosspolymer.   A dispersion liquid containing the surface-treated zinc oxide particles according to any one of claims 1 to 4 and a dispersion medium.   A cosmetic containing at least one selected from the group consisting of the surface-treated zinc oxide particles according to any one of claims 1 to 4 and the dispersion according to claim 5. The following formula (1) is less than,
Zinc oxide particles having a Na content M in the following formula (1) of 20 mg / kg or more and 200 mg / kg or less .
S · M / σ ² ≧ 0.05 (1)
(S is the specific surface area of zinc oxide particles (unit: m ² / g), M is the Na content of zinc oxide particles (unit: mg / kg), σ is 10 parts by mass of zinc oxide particles and 90 parts by mass of pure water. Is the conductivity (unit: μS / cm) of the slurry obtained by mixing for 1 hour.)

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