JP2019064936A - Silicon oxide-coated zinc oxide particle-containing aqueous composition, and cosmetics - Google Patents

Abstract

To provide a silicon oxide-coated zinc oxide particle-containing aqueous composition which facilitates uniform mixing of silicon oxide-coated zinc oxide particles when making oil-in-water emulsion, and has excellent dispersion stability, and cosmetics containing the same.SOLUTION: A silicon oxide-coated zinc oxide particle-containing aqueous composition contains water, a nonionic surfactant, a water-soluble vinyl polymer, and silicon oxide-coated zinc oxide particles. When it is blended in gel containing a carboxyvinyl polymer, the agglomerated particles are 60 μm or less in sizes.SELECTED DRAWING: None

Description

  The present invention relates to an aqueous composition containing silicon oxide-coated zinc oxide particles and a cosmetic.

  Cosmetics provided with a UV shielding function are frequently used on a daily basis as well as leisure applications. Therefore, for cosmetics, a feeling that does not feel stress so as to be used daily is emphasized. In order to obtain such feeling, as a cosmetic, a water-based product with a fresh feeling of use is required.

  Water-based cosmetics are less sticky and have less burden on the skin than oil-based cosmetics, and have recently been used as various oil-in-water (O / W) cosmetics such as sunscreens, emulsions, and creams. ing.

  As ultraviolet shielding particles that can be used for such water-based cosmetics, zinc oxide particles coated with silicon oxide are known (see, for example, Patent Documents 1 and 2).

International Publication No. 2014/171322 International Publication No. 2015/072499

  However, when a water-based cosmetic is prepared using silicon oxide-coated zinc oxide particles described in Patent Document 1 and Patent Document 2, mixing silicon oxide-coated zinc oxide particles in water-based cosmetic However, there is a problem that the desired ultraviolet shielding properties can not be obtained when this mixture is used as a coating.

  The present invention has been made in view of the above circumstances, and provides a silicon oxide-coated zinc oxide particle-containing aqueous composition having excellent ultraviolet shielding properties even when applied to an aqueous cosmetic, and a cosmetic comprising the same The purpose is to

  As a result of intensive studies to solve the above problems, the present inventors have found that silicon oxide-coated zinc oxide particles obtained by coating the surface of zinc oxide particles with a silicon oxide film, a water-soluble vinyl polymer, If an ionic surfactant is dispersed in water to form an aqueous dispersion, and this aqueous dispersion is applied to the aqueous phase of the cosmetic composition, the ultraviolet shielding performance is improved, the transparency is also excellent, and zinc ions It has been found that the problem caused by elution is also solved, and the present invention has been completed.

  That is, the aqueous composition containing silicon oxide-coated zinc oxide particles of the present invention comprises water, a nonionic surfactant, a water-soluble vinyl polymer, and silicon oxide-coated zinc oxide particles, and a carboxyvinyl polymer The agglomerated particle size is 60 μm or less when blended in a gel containing

  The cosmetic of the present invention is characterized by containing the silicon oxide-coated zinc oxide particle-containing aqueous composition of the present invention and a cosmetic base material.

  The oil-in-water cosmetic of the present invention is characterized in that the silicon oxide-coated zinc oxide particle-containing aqueous composition of the present invention is contained in the aqueous phase.

  According to the water-based composition containing silicon oxide-coated zinc oxide particles of the present invention, even when applied to a water-based cosmetic, it has excellent ultraviolet shielding properties.

  According to the cosmetic of the present invention, since the silicon oxide-coated zinc oxide particle-containing aqueous composition of the present invention is contained, a cosmetic excellent in the ultraviolet shielding effect and the feeling in use can be obtained.

  According to the oil-in-water cosmetic of the present invention, since the silicon oxide-coated zinc oxide particle-containing aqueous composition of the present invention is contained, a cosmetic excellent in ultraviolet shielding effect and feeling of use can be obtained.

It is an optical microscope observation image of the water-based cosmetic of Example 1. It is a figure which shows the transmittance | permeability curve of water-based cosmetics of Examples 1-3 and a comparative example. FIG. 2 is a view showing the change with time of the viscosity at 40 ° C. of the water-based composition of Example 1. 3 is an optical microscope observation image of the oil-in-water cosmetic of Example 1. FIG. It is an optical microscope observation image of the water-based cosmetic of Example 2. 7 is an optical microscope observation image of the oil-in-water cosmetic of Example 2. FIG. It is an optical microscope observation image of the water-based cosmetic of Example 3. 7 is an optical microscope observation image of the oil-in-water cosmetic of Example 3. FIG. It is an optical microscope observation image of the water-based cosmetics of a comparative example. It is an optical microscope observation image of the oil-in-water type cosmetics of a comparative example.

The silicon oxide-coated zinc oxide particle-containing aqueous composition of the present invention, and a cosmetic containing the same, and a preferred embodiment for practicing an oil-in-water cosmetic are described.
The following embodiments are specifically described for better understanding of the gist of the invention, and the invention is not limited unless otherwise specified.

[Water-based composition containing silicon oxide-coated zinc oxide particles]
The water-based composition containing silicon oxide-coated zinc oxide particles according to this embodiment contains water, a nonionic surfactant, a water-soluble vinyl polymer, and silicon oxide-coated zinc oxide particles, and is a carboxyvinyl polymer. It is a composition having an aggregate particle diameter of 60 μm or less when it is blended in a gel to be contained.

Here, a gel containing a carboxyvinyl polymer means a carboxyvinyl polymer gel containing 0.2% by mass of a carboxyvinyl polymer and adjusted to pH 7.5 with an aqueous solution of sodium hydroxide. That is, carboxyvinyl polymer gel is composed only of carboxyvinyl polymer, sodium hydroxide and water.
Moreover, being mix | blended with the gel containing a carboxy vinyl polymer means mixing 90 mass parts of carboxy vinyl polymer gels, and 10 mass of silicon-oxide-coated zinc oxide particle containing water-based compositions of this embodiment.

  The silicon oxide-coated zinc oxide particle-containing composition of the present embodiment may be liquid or gel.

  In the silicon oxide-coated zinc oxide particle-containing water-based composition of the present embodiment, as required, dispersants, stabilizers, water-soluble binders, thickeners, alcohols, chelating agents, etc. are generally used in water-based cosmetics. Additives may be included.

In the silicon oxide-coated zinc oxide particle-containing water-based composition of the present embodiment, the content of the nonionic surfactant per 100 parts by mass of the silicon oxide-coated zinc oxide particles is 0.1 parts by mass or more and 10.0 parts by mass or less And more preferably 0.2 parts by mass or more and 9.0 parts by mass or less and still more preferably 0.5 parts by mass or more and 8.0 parts by mass or less.
When the content of the nonionic surfactant is 0.1 parts by mass or more and 10.0 parts by mass or less based on 100 parts by mass of the silicon oxide-coated zinc oxide particles, the ultraviolet shielding is performed even when applied to a water-based cosmetic It is preferable because the effect of improving the property can be easily obtained.

Moreover, in the silicon oxide-coated zinc oxide particle-containing water-based composition of the present embodiment, the content of the nonionic surfactant is preferably 0.1% by mass or more and 10% by mass or less. % Or more and 7% by mass or less is more preferable, and 0.1% by mass or more and 5% by mass or less is more preferable.
In the silicon oxide-coated zinc oxide particle-containing water-based composition of the present embodiment, the total content of the respective components is 100% by mass, and the total content of the respective components does not exceed 100% by mass.

A non-ionic surfactant is a surfactant having a hydrophilic group that does not ionize when it is dissolved in water, and is less susceptible to the influence of water hardness and electrolyte.
The nonionic surfactant is not particularly limited as long as it can be mixed with water at an arbitrary ratio and can be used for cosmetics.
As such a nonionic surfactant, an ester surfactant, an ether surfactant, an ester / ether surfactant or the like can be used. One of these nonionic surfactants may be used alone, or two or more thereof may be used in combination.

  The ester surfactant has a structure in which a polyhydric alcohol such as glycerin, sorbitol or sucrose and a fatty acid are ester-linked. As ester type surfactant, glycerine fatty acid ester, sorbitan fatty acid ester, sucrose fatty acid ester etc. are mentioned, for example.

  The ether type surfactant is obtained by mainly adding ethylene oxide to a substance having a hydroxyl group such as higher alcohol or alkylphenol. Examples of the ether type surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene polyoxypropylene glycol and the like. As polyoxyethylene alkyl ether, for example, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene alkyl ether, polyoxyethylene milliester ether, polyoxyethylene Octyl dodecyl ether etc. are mentioned.

  The ester / ether type surfactant is obtained by adding ethylene oxide to an ester composed of a polyhydric alcohol such as glycerin and sorbitol and a fatty acid. Examples of the ester / ether type surfactant include polyoxyethylene glycol and polyoxyethylene oleic acid ester.

One of these nonionic surfactants may be used alone, or two or more thereof may be used in combination.
Further, among these nonionic surfactants, ether surfactants are preferable, from the viewpoint of being able to easily prepare a cosmetic, because the viscosity decrease, the viscosity increase, and the influence on other components are small, and polyoxyethylene surfactants are preferable. Alkyl ethers are more preferred, and polyoxyethylene octyl dodecyl ether is more preferred.

In the silicon oxide-coated zinc oxide particle-containing water-based composition of the present embodiment, the content of the water-soluble vinyl polymer is 100 parts by mass to 0.02 parts by mass with respect to 100 parts by mass of the silicon oxide-coated zinc oxide particles And 0.05 parts by mass or more and 5.0 parts by mass or less, and more preferably 0.1 parts by mass or more and 4.5 parts by mass or less.
When the content of the water-soluble vinyl polymer is 0.02 parts by mass or more and 6.0 parts by mass or less based on 100 parts by mass of the silicon oxide-coated zinc oxide particles, the ultraviolet ray shielding property is obtained even when applied to a water-based cosmetic It is preferable because the improvement of the

  In the silicon oxide-coated zinc oxide particle-containing aqueous composition according to this embodiment, the content of the water-soluble vinyl polymer is preferably 0.02% by mass or more and 6.0% by mass or less, and 0.05 It is more preferable that it is mass% or more and 5.0 mass% or less, and it is further more preferable that it is 0.1 mass% or more and 4.5 mass% or less.

The water-soluble vinyl polymer is not particularly limited as long as it can be mixed with water in any proportion and can be used for cosmetics.
As such a water-soluble vinyl polymer, a carboxyvinyl polymer, an alkyl-modified carboxyvinyl polymer, an alkyl acrylate / methacrylic acid / polyoxyethylene copolymer, etc. can be used. One of these water-soluble vinyl polymers may be used alone, or two or more thereof may be used in combination.
Among these water-soluble vinyl polymers, it is more preferable to use an alkyl-modified carboxyvinyl polymer. The alkyl-modified carboxyvinyl polymer is the same component as the thickener even if it is added to water-based cosmetics or oil-in-water cosmetics thickened with a carboxyvinyl polymer, alkyl-modified carboxyvinyl polymer, etc. The cosmetic composition can be easily prepared with little impact on other ingredients.

  As the carboxyvinyl polymer, for example, Carbopol (registered trademark) 940, Carbopol (registered trademark) 941, Carbopol (registered trademark) 980, Carbopol (registered trademark) 981, Carbopol (registered trademark) Ultrez 10 (manufactured by Lubrizol Advanced Materials) What is known by a brand name is mentioned.

  As the alkyl-modified carboxyvinyl polymer, for example, those known under the trade name of Carbopol (registered trademark) 1342, PEMULEN (registered trademark) TR-1, PEMULEN (registered trademark) TR-2 (manufactured by Lubrizol Advanced Materials) Can be mentioned.

In the case of using an alkyl-modified carboxyvinyl polymer as the water-soluble vinyl polymer, in the aqueous composition containing silicon oxide-coated zinc oxide particles of the present embodiment, the inclusion of the alkyl-modified carboxyvinyl polymer relative to 100 parts by mass of silicon oxide-coated zinc oxide particles The amount is preferably 0.02 parts by mass or more and 6.0 parts by mass or less, more preferably 0.05 parts by mass or more and 5.0 parts by mass or less, 0.1 parts by mass or more and 4. parts by mass. More preferably, it is 5 parts by mass or less.
When the content of the alkyl-modified carboxyvinyl polymer relative to 100 parts by mass of the silicon oxide-coated zinc oxide particles is 0.02 parts by mass or more and 6.0 parts by mass or less, the ultraviolet shielding properties even when applied to water-based cosmetics It is preferable because the improvement of the

As an alkyl acrylate / methacrylic acid / polyoxyethylene copolymer, for example, (acreates / steareth methacrylate 20) copolymer, (acreates / beh heth methacrylate 25) copolymer, (acreates / steareth methacrylate 20) cloth Polymer is mentioned. In addition, Accurin (registered trademark) 22, Accurin (registered trademark) 28, and Accurin (registered trademark) 88, which are commercially available from Rohm & Haas, may be used as the alkyl acrylate / methacrylic acid / polyoxyethylene copolymer. Good.
Among these alkyl acrylate / alkyl methacrylate / polyoxyethylene copolymers, Accurin (registered trademark) 22 (acrylates / steareth methacrylate 20) copolymer is particularly preferable in that it is free from stickiness and has a good feeling in use. is there.

  In order to improve the dispersibility of the nonionic surfactant and the silicon oxide-coated zinc oxide particles in water, the water-based composition containing silicon oxide-coated zinc oxide particles of the present embodiment preferably contains an alcohol.

In the silicon oxide-coated zinc oxide particle-containing water-based composition according to the present embodiment, the content of the alcohol is preferably 10 parts by mass to 100 parts by mass with respect to 100 parts by mass of the silicon oxide-coated zinc oxide particles, and 20 parts by mass More preferably, it is 50 parts by mass or less.
If the content of the alcohol relative to 100 parts by mass of the silicon oxide-coated zinc oxide particles is 10 parts by mass or more, the dispersibility of the silicon oxide-coated zinc oxide particles can be further improved. On the other hand, when the content of alcohol relative to 100 parts by mass of silicon oxide-coated zinc oxide particles is 100 parts by mass or less, deterioration of stickiness and feel when a silicon oxide-coated zinc oxide particle-containing aqueous composition is blended in a cosmetic It can be suppressed.

  Moreover, in the silicon oxide-coated zinc oxide particle-containing aqueous composition according to the present embodiment, the content of the alcohol is preferably 0.1% by mass or more and 30% by mass or less, and 0.3% by mass or more and 25% by mass. It is more preferable that it is mass% or less, and it is further more preferable that it is 0.5 mass% or more and 20 mass% or less.

The alcohols are not particularly limited as long as they can be used for cosmetics, and examples thereof include ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, octanol, glycerin and 1,3-butylene glycol C1-C6 monohydric alcohols, such as propylene glycol and sorbitol, polyhydric alcohols, etc. can be used.
Among these alcohols, glycerin is preferable in that it is widely used for cosmetics because it improves the feel and moisturizing effect of cosmetics.

The silicon oxide-coated zinc oxide particle-containing aqueous composition according to the present embodiment has an aggregate particle diameter of 60 μm or less, preferably 50 μm or less, and 45 μm or less, when it is blended in a cosmetic containing carboxyvinyl polymer Is more preferred. The lower limit of the agglomerated particle size is about 35 nm, which is equivalent to the particle size of the silicon oxide-coated zinc oxide particles.
When the aggregated particle size exceeds 60 μm, it is shown that silicon oxide-coated zinc oxide particles are easily aggregated in a cosmetic containing a carboxyvinyl polymer. When such silicon oxide-coated zinc oxide particles are blended in a cosmetic containing a carboxyvinyl polymer, it becomes difficult to uniformly apply the silicon oxide-coated zinc oxide particles to the skin. As a result, the desired ultraviolet shielding performance (SPF) can not be obtained. In addition, the feel when applied to the skin is deteriorated.

In the silicon oxide-coated zinc oxide particle-containing water-based composition according to this embodiment, the aggregated particle size in the case of being incorporated into a cosmetic containing a carboxyvinyl polymer is the silicon oxide-coated in a cosmetic containing a carboxyvinyl polymer. It is the maximum particle size of an aggregate formed by aggregation of primary particles of zinc oxide particles. That is, the agglomerated particle size refers to the largest size of an aggregate generated when the silicon oxide-coated zinc oxide particle-containing aqueous composition of the present embodiment and a cosmetic containing a carboxyvinyl polymer are mixed. It is.
The agglomerated particle size was observed with an optical microscope by sandwiching a mixture of a silicone oxide-coated zinc oxide particle-containing aqueous composition of this embodiment and a cosmetic containing a carboxyvinyl polymer between two glass slides. Sometimes it means the largest particle size of the observed aggregates.

The silicon oxide-coated zinc oxide particle-containing water-based composition of the present embodiment has a viscosity of 0.1 Pa · s or more when measured under conditions of 20 ° C. and 30 rotations (rpm) using a BII rotational viscometer. The pressure is preferably 50 Pa · s or less, more preferably 0.2 Pa · s or more and 30 Pa · s or less, and still more preferably 0.3 Pa · s or more and 15 Pa · s or less.
When the viscosity of the silicon oxide-coated zinc oxide particle-containing aqueous composition is in the above range, the silicon oxide-coated zinc oxide particle-containing aqueous composition can be suitably used for an oil-in-water cosmetic.

The silicon oxide-coated zinc oxide particle-containing aqueous composition according to this embodiment preferably has a viscosity of 0.1 Pa · s or more and 15 Pa · s or less after storage for 2 weeks at 40 ° C., and 0.2 Pa · s. It is more preferable that it is s or more and 13 Pa · s or less, and further preferably 0.3 Pa · s or more and 10 Pa · s or less.
Even when stored at 40 ° C. for 2 weeks, the viscosity of the silicon oxide-coated zinc oxide particle-containing aqueous composition is within the above range, so that the performance as an oil-in-water cosmetic can be maintained, which is preferable. .

The silicon oxide-coated zinc oxide particle-containing aqueous composition according to this embodiment preferably has a hydrogen ion index (pH) of 6.0 or more and 9.0 or less, and is 6.5 or more and 9.0 or less Is more preferably 7.0 or more and 9.0 or less.
When the pH is in the above range, it can be suitably used for an oil-in-water cosmetic.

Further, the silicon oxide-coated zinc oxide particle-containing aqueous composition of the present embodiment preferably has a hydrogen ion index (pH) of 6.0 or more and 9.0 or less after storage at 40 ° C. for one month, It is more preferably 6.5 or more and 9.0 or less, and still more preferably 7.0 or more and 9.0 or less.
Even when stored at 40 ° C. for one month, the hydrogen ion index being in the above range is preferable because it can maintain the performance that can be used as the hydrogen ion index of cosmetics.

The viscosity of the silicon oxide-coated zinc oxide particle-containing water-based composition according to the present embodiment is, for example, a viscosity when stored at 40 ° C. when stored under accelerated conditions, and a viscosity measured after one month has elapsed. Is preferably divided by a viscosity after viscosity reduction under initial conditions, for example, a viscosity measured after lapse of 720 hours at 40.degree. C., which is preferably 0.7 or more and 1.0 or less.
As described above, the silicon oxide of the present embodiment is obtained by setting the value obtained by dividing the viscosity after 1 month progress under the acceleration condition, that is, the viscosity after the viscosity decrease under the initial condition, into the above range. The viscosity of the coated zinc oxide particle-containing aqueous composition can be maintained over a medium to long period. The water-based composition containing silicon oxide-coated zinc oxide particles as described above can be obtained by controlling (adjusting) the conditions described herein.

  The silicon oxide-coated zinc oxide particle-containing water-based composition of the present embodiment is diluted with an alcohol as necessary, and the content of silicon oxide-coated zinc oxide particles in the silicon oxide-coated zinc oxide particle-containing water-based composition is 5% by mass. When a thin film having a thickness of 12 μm (an aqueous composition containing silicon oxide-coated zinc oxide particles) is formed using this composition, the thin film preferably has a transmittance of 40% or more for light of 450 nm wavelength. % Or more is more preferable, and 60% or more is more preferable. The transmittance is a silicon oxide-coated zinc oxide particle-containing aqueous composition containing 5% by mass of silicon oxide-coated zinc oxide particles to form a thin film on a quartz substrate to a thickness of 12 μm, and the spectral transmittance of the thin film It can obtain | require by measuring by SPF analyzer UV-1000S (made by Labsphere).

Water is not particularly limited as long as it is water generally used for cosmetics, and pure water, ion exchanged water, distilled water, purified water, ultrapure water, natural water, alkali metal ion water, deep layer water, etc. Used.
The content of water in the silicon oxide-coated zinc oxide particle-containing aqueous composition of the present embodiment is appropriately adjusted according to the desired characteristics. The content of water is preferably 10% by mass or more and 99% by mass or less, and 20% by mass or more and 95% by mass or less from the viewpoint of improving the feeling of use of the silicon oxide-coated zinc oxide particle-containing aqueous composition It is more preferable that it is 40 mass% or more and 94 mass% or less.

The silicon oxide-coated zinc oxide particles are not particularly limited as long as they can suppress increase and decrease in viscosity and fluctuation in pH when mixed in water to form an aqueous composition.
Such silicon oxide-coated zinc oxide particles are obtained by coating the surface of zinc oxide particles with a silicon oxide film, and the silicon oxide film is dense or remains in the silicon oxide-coated zinc oxide particles. It is preferable to use an alkali metal substituted by at least one selected from the group consisting of Mg, Ca and Ba.

  The content of the silicon oxide-coated zinc oxide particles in the silicon oxide-coated zinc oxide particle-containing water-based composition of the present embodiment is appropriately adjusted according to the desired characteristics. The content of the silicon oxide-coated zinc oxide particles is preferably 1% by mass or more and 80% by mass or less, and more preferably 5% by mass or more and 70% by mass or less from the viewpoint of transparency and ultraviolet shielding properties Preferably, the content is 10% by mass or more and 70% by mass or less, and most preferably 20% by mass or more and 65% by mass or less.

(Example 1 of silicon oxide coated zinc oxide particles)
An example of a silicon oxide-coated zinc oxide particle having a dense silicon oxide film is a silicon oxide-coated zinc oxide particle formed by coating the surface of a zinc oxide particle with a silicon oxide film, and Q ³ of silicon in the silicon oxide film the abundance ratio in the environment ^{Q 3,} when the presence ratio in ^{Q 4} environment of silicon oxide, silicon in the coating film was ^{Q 4, Q 3 + Q 4} ≧ 0.6 and ^{Q 4 / (Q 3 + Q} 4) ≧ 0.5 And silicon oxide-coated zinc oxide particles. Furthermore, it is preferable that the silicon oxide film uniformly coats the entire zinc oxide particles to such an extent that the decomposition rate of brilliant blue generated by the photocatalytic activity of the silicon oxide-coated zinc oxide particles is 3% or less.

The silicon oxide film is, "when Q ³ of the presence ratio in Q ³ environments of silicon oxide, silicon in the ^coating, the presence ratio in Q ⁴ environment of silicon oxide, silicon in the coating film was ^{Q 4, Q 3 + Q 4} ≧ 0. As long as 6 and Q ⁴ / (Q ³ + Q ⁴ ) ≧ 0.5 ”are satisfied, the degree of condensation may be high.
There is a close relationship between the "fineness" of the dense silicon oxide film and the "degree of condensation" of the silicon oxide, and the higher the degree of condensation of the silicon oxide, the higher the denseness of the silicon oxide film. It becomes.
That is, the term “compact” of the dense silicon oxide film referred to herein means that the degree of condensation of silicon oxide is such that Q ³ + Q ⁴ 0.60.6 and Q ⁴ / (Q ³ + Q ⁴ ) ≧ 0.5. It means the silicon oxide film in the high state.

Regarding the degree of condensation of silicon oxide, the NMR spectrum of silicon oxide-coated zinc oxide particles is measured by solid state ²⁹ Si MAS-nuclear magnetic resonance (NMR) spectroscopy, and from the peak area ratio of this NMR spectrum, Q ⁰ , Q ¹ , It can be easily known by measuring the area ratio of signals assigned to the environments of Q ² , Q ³ and Q ⁴ .
Here, Q ⁿ (n = 0 to 4) means a bridging oxygen atom among oxygen atoms of SiO ₄ tetrahedral unit which is a constituent unit of silicon oxide, that is, oxygen atoms bonded to two Sis. It is a chemical structure that depends on the number.
These ^{Q 0, Q 1, Q 2} , Q 3, Q 4 area ratio of the signal to be attributed to each ^environment, referred to as ^{Q 0, Q 1, Q 2} , Q 3, Q 4. ^However, it is ^{Q 0 + Q 1 + Q 2} + Q 3 + Q 4 = 1.

  The reason why the decomposition rate of brilliant blue generated by the photocatalytic activity of silicon oxide-coated zinc oxide particles is preferably 3% or less will be described below. The reason is that if the decomposition rate of this brilliant blue is 3% or less, the photocatalytic activity of the zinc oxide particles is suppressed, so that the homogeneity of the silicon oxide film covering the zinc oxide particles is also high. Because it means Here, the high homogeneity of the silicon oxide film covering the zinc oxide particles indicates that there is no uneven coating, that the film is not localized, and that there is no pinhole or the like. The decomposition rate of brilliant blue is used as an indicator of the photocatalytic activity of zinc oxide particles. The photocatalytic reaction of zinc oxide particles basically takes place on the surface of the zinc oxide particles. That is, the low decomposition rate of brilliant blue generated by the photocatalytic activity of the zinc oxide particles indicates that the zinc oxide particles are less exposed at the surface of the silicon oxide-coated zinc oxide.

The method of measuring the degradation rate of brilliant blue is as follows.
First, a brilliant blue aqueous solution having a prescribed content (for example, 5 ppm) of brilliant blue is prepared, and a predetermined amount of this brilliant blue aqueous solution is collected into a screw tube, and this collected brilliant blue aqueous solution is converted to zinc oxide particles. Silicon oxide-coated zinc oxide particles of 1% by mass with respect to the mass of the aqueous solution are charged and ultrasonically dispersed to prepare a suspension.
Next, ultraviolet light of a predetermined wavelength is irradiated to the suspension from a predetermined distance (for example, 10 cm) for a predetermined time (for example, 6 hours) using an ultraviolet irradiation lamp.
As the ultraviolet irradiation lamp, for example, a sterilization lamp GL20 (wavelength 253.7 nm, ultraviolet output 7.5 W: manufactured by Toshiba Corporation) can be used.

Next, the supernatant is collected from the suspension irradiated with the ultraviolet light, and the absorptiance spectra of the above-mentioned brilliant blue aqueous solution and the supernatant are measured by atomic absorption spectrophotometry.
Then, using these measured values, the decomposition rate D of brilliant blue is calculated by the following equation (1).
D = (A0-A1) / A0 ... (1) (where A0 is the absorbance at the absorption maximum wavelength (630 nm) of the absorptiometry spectrum of brilliant blue aqueous solution (5 ppm), A1 is the absorptiance spectrum of the above supernatant liquid Absorption at the absorption maximum wavelength of

  In addition, it was 90% as a result of measuring the decomposition rate of brilliant blue about the normal zinc oxide particle (average particle diameter 35 nm; Sumitomo Osaka Cement Co., Ltd. make) based on said method. Thus, it was confirmed that the zinc oxide particles (average particle diameter: 35 nm; manufactured by Sumitomo Osaka Cement Co., Ltd.) have high decomposition rate of Brilliant Blue when having photocatalytic activity.

  The average primary particle diameter of the silicon oxide-coated zinc oxide particles is preferably 3 nm or more and 2 μm or less, and the above-mentioned silicon oxide-coated zinc oxide particle-containing aqueous composition has the above-mentioned desired transparency and ultraviolet shielding properties. It adjusts suitably within the range. When it is desired to obtain a highly transparent silicon oxide-coated zinc oxide particle-containing aqueous composition, the average primary particle diameter of the silicon oxide-coated zinc oxide particles is preferably 1 nm or more and 50 nm or less. On the other hand, in order to improve the ultraviolet shielding properties of the silicon oxide-coated zinc oxide particle-containing aqueous composition, the average primary particle diameter of the silicon oxide-coated zinc oxide particles is preferably 50 nm or more and 2 μm or less.

The “average primary particle diameter” in the silicon oxide-coated zinc oxide particles constituting the silicon oxide-coated zinc oxide particle-containing aqueous composition of the present embodiment is a numerical value determined by the following method. That is, when the silicon oxide-coated zinc oxide particles constituting the water-based composition containing silicon oxide-coated zinc oxide particles of the present embodiment are observed using a transmission electron microscope (TEM) or the like, the silicon oxide-coated zinc oxide particles are A predetermined number, for example, 200 or 100 is selected. Then, the longest linear portion (maximum major axis) of each of these silicon oxide-coated zinc oxide particles is measured, and these measured values are weighted and averaged.
In the case where silicon oxide-coated zinc oxide particles are agglomerated, the agglomerated particle size of the agglomerate is not measured. A predetermined number of particle sizes (primary particle sizes) of silicon oxide-coated zinc oxide particles constituting the aggregates are measured to obtain an average primary particle size.

  The content of zinc oxide particles in silicon oxide-coated zinc oxide particles is preferably 50% by mass or more and 90% by mass or less. Here, if the content of zinc oxide particles in silicon oxide-coated zinc oxide particles is 50% by mass or more, a desired ultraviolet shielding effect can be obtained. That is, it is not necessary to use a large amount of silicon oxide-coated zinc oxide particles in order to obtain a desired ultraviolet shielding effect. On the other hand, if the content of zinc oxide particles in silicon oxide-coated zinc oxide particles is 90% by mass or less, the ratio of zinc oxide particles in silicon oxide-coated zinc oxide particles does not become too high, and the surface of zinc oxide particles It can be fully covered with a silicon oxide film.

When silicon oxide-coated zinc oxide particles are immersed in an aqueous solution having a hydrogen ion index of 5 for 1 hour so as to be 0.05% by mass, the elution ratio of zinc ions eluted in the aqueous solution is 60% by mass or less The content is preferably 20% by mass or less, and more preferably 10% by mass or less.
Here, the reason why the dissolution rate of zinc ions is preferably 60% by mass or less is that if the dissolution rate of zinc ions is 60% by mass or less, the stability of the silicon oxide-coated zinc oxide particles themselves is improved When the silicon oxide-coated zinc oxide particles are applied to a cosmetic, the zinc ions eluted do not react with the organic ultraviolet screening agent, the water-soluble polymer such as a thickener, etc. There is no decline in the performance as a filler, no discoloration, and no increase or decrease in viscosity.

For the dissolution rate of zinc ions, for example, silicon oxide-coated zinc oxide particles are dispersed in a pH = 5 buffer solution to 0.05 mass%, stirred for 1 hour, and then solid-liquid separation is performed to obtain liquid phase The zinc concentration can be measured by measuring with an ICP emission analyzer.
The buffer solution of pH = 5 is not particularly limited as long as it is a buffer solution capable of dispersing silicon oxide-coated zinc oxide particles, and for example, 500 ml of a 0.1 M aqueous solution of potassium hydrogen phthalate and 0.1 M sodium hydroxide After mixing with the aqueous solution 226 ml, water is added to make the total volume 1000 ml, and a buffer solution is preferably used.

  The average primary particle size of the zinc oxide particles is appropriately adjusted in order for the silicon oxide-coated zinc oxide particle-containing aqueous composition to obtain desired transparency and ultraviolet shielding properties. When it is desired to obtain a highly transparent silicon oxide-coated zinc oxide particle-containing aqueous composition, the average primary particle diameter of the zinc oxide particles is preferably 1 nm or more and 50 nm or less. On the other hand, when it is desired to improve the ultraviolet shielding properties of the silicon oxide-coated zinc oxide particle-containing aqueous composition, the average primary particle diameter of the zinc oxide particles is preferably 50 nm or more and 500 nm or less.

A method of producing such silicon oxide coated zinc oxide particles is detailed in WO 2014/171322. According to this manufacturing method, zinc oxide particles are coated with a silicon oxide film on the surface of zinc oxide particles using alkoxysilane or sodium silicate and alkoxysilane, and baked at 200 ° C. to 600 ° C. Thus, silicon oxide-coated zinc oxide particles having a dense silicon oxide film are obtained.
In addition, when using a zinc oxide particle whose average primary particle diameter is 50 nm or more, you may bake at 150 degreeC-600 degreeC.

(Example 2 of silicon oxide coated zinc oxide particles)
Another example of the silicon oxide-coated zinc oxide particles is silicon oxide-coated zinc oxide particles obtained by coating the surface of zinc oxide particles with a silicon oxide film, and at least selected from the group consisting of Mg, Ca and Ba. Examples include silicon oxide-coated zinc oxide particles containing one kind. The reason why it is preferable to use the silicon oxide-coated zinc oxide particles is as follows.

  In order to uniformly coat the entire surface of zinc oxide particles with a silica coating so that the decomposition rate of brilliant blue generated by the photocatalytic activity of silicon oxide-coated zinc oxide particles is 3% or less, the film contains an alkali metal such as sodium silicate Preferably, the material is used to form a silicon oxide film. However, when the alkali metal remains in the silicon oxide-coated zinc oxide particles, when the silicon oxide-coated zinc oxide particles are dispersed in the aqueous phase, the alkali metal ions are eluted and the pH and viscosity are largely changed. , The quality stability as a cosmetic is lost.

Therefore, oxidation of silicon oxide-coated zinc oxide particles is carried out by replacing the alkali metal contained in the silicon oxide film of the silicon oxide-coated zinc oxide particles with at least one selected from the group consisting of Mg, Ca and Ba. The alkali metal contained in the silicon coating is removed from the silicon oxide coating of the silicon oxide coated zinc oxide particles.
On the other hand, at least one selected from the group consisting of alkali metal substituted Mg, Ca and Ba contained in the silicon oxide film is present in the silicon oxide film of silicon oxide coated zinc oxide particles after substitution. . These substituted Mg, Ca and Ba are present as magnesium silicate, calcium silicate, barium silicate and the like which have low water solubility.

  As a result of the substitution, the mass percentage of the total of at least one selected from the group consisting of Mg, Ca and Ba contained in the silicon oxide film of the silicon oxide coated zinc oxide particles is that of the alkali metal contained in the silicon oxide film. It becomes larger than mass percentage. Therefore, even if the silicon oxide-coated zinc oxide particles are mixed in the aqueous phase, the elution of the alkali metal can be suppressed, and fluctuations in pH and viscosity can be suppressed, and quality stability as a cosmetic can be maintained. it can.

  The average primary particle diameter of the silicon oxide-coated zinc oxide particles is selected as necessary, but is preferably 2 nm or more and 2 μm or less, more preferably 5 nm or more and 500 nm or less, and 10 nm or more and 400 nm or less It is further preferred that

  The smaller the average primary particle size of the silicon oxide-coated zinc oxide particles, the more suitable it is for increasing the transparency when used in cosmetics. On the other hand, as the average primary particle diameter of the silicon oxide-coated zinc oxide particles is larger, the scattering intensity of the ultraviolet light is also higher, and the ultraviolet light up to the long wavelength can be shielded. Therefore, the average primary particle diameter of the silicon oxide-coated zinc oxide particles is appropriately selected in accordance with the transparency of the intended cosmetic and the shielding property of ultraviolet light.

The content of zinc oxide particles in silicon oxide-coated zinc oxide particles is selected as necessary, but is preferably 50% by mass or more and 99% by mass or less, and is 70% by mass or more and 95% by mass or less It is more preferable that it is 70 mass% or more and 90 mass% or less.
Here, if the content of zinc oxide particles in silicon oxide-coated zinc oxide particles is 50% by mass or more, a desired ultraviolet shielding effect can be obtained. In cosmetics containing such silicon oxide-coated zinc oxide particles in a base, it is not necessary to use a large amount of silicon oxide-coated zinc oxide particles in order to obtain a desired ultraviolet shielding effect.
On the other hand, when the content of zinc oxide particles in silicon oxide-coated zinc oxide particles is 99% by mass or less, the proportion of zinc oxide particles in the silicon oxide-coated zinc oxide particles does not become too high. Therefore, the surface of zinc oxide particles can be sufficiently covered with a silicon oxide film, and the photocatalytic activity of zinc oxide particles and the elution of zinc ions can be sufficiently suppressed.

  The content of silicon oxide in the silicon oxide-coated zinc oxide particles is appropriately adjusted according to the average primary particle size of the zinc oxide particles. For example, with respect to zinc oxide particles having an average primary particle size of 50 nm or less, the content of silicon oxide is preferably 3% by mass or more and 45% by mass or less. Moreover, regarding the zinc oxide particle whose average primary particle diameter exceeds 50 nm, it is preferable that content of a silicon oxide is 1 mass% or more and 35 mass% or less.

The silicon oxide-coated zinc oxide particles contain at least one selected from the group consisting of Mg, Ca and Ba.
In the silicon oxide-coated zinc oxide particles, the mass percentage of the total of at least one selected from the group consisting of Mg, Ca and Ba contained in the silicon oxide film is from the mass percentage of the alkali metal contained in the silicon oxide film It is preferably large. Furthermore, the ratio of the mass percentage of alkali metal contained in the silicon oxide film to the mass percentage of the total of at least one selected from the group consisting of Mg, Ca and Ba contained in the silicon oxide film (mass of alkali metal Percentage / mass percentage of the total of at least one selected from the group consisting of Mg, Ca and Ba) is preferably 0.001 or more and 0.6 or less, and is 0.01 or more and 0.5 or less And more preferably 0.1 or more and 0.4 or less.
In the present embodiment, an alkali metal refers to a generally known one, and specifically, lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs) And at least one selected from the group consisting of francium (Fr).

  Here, the reason why the mass percentage of the total of at least one selected from the group consisting of Mg, Ca and Ba contained in the silicon oxide film is larger than the mass percentage of the alkali metal contained in the silicon oxide film is The main factor of the variation of the hydrogen ion index (pH) in the initial stage of silicon oxide-coated zinc oxide particles is not the elution of zinc ions contained in silicon oxide-coated zinc oxide particles but the alkali metal contained in the silicon oxide film It is the elution of ions.

The mass percentage of the alkali metal contained in the silicon oxide film in the silicon oxide-coated zinc oxide particles is preferably 0.8 mass% or less, more preferably 0.6 mass% or less, 0.2 mass It is further preferable that the content is less than or equal to%.
The lower limit of the mass percentage of the alkali metal contained in the silicon oxide film can be arbitrarily selected. The percentage by mass of the alkali metal may be 0%, and for example, it may be 0.0001% by mass or more, 0.001% by mass or more, to mention another example.

  The mass percentage of the total of at least one selected from the group consisting of Mg, Ca and Ba contained in the silicon oxide film in the silicon oxide-coated zinc oxide particles is 0.01% by mass or more and 1% by mass or less Is preferred.

  The mass percentage (mass%) of the alkali metals, Mg, Ca and Ba contained in the silicon oxide-coated zinc oxide particles (silicon oxide film) can be measured by atomic absorption spectrometry.

In silicon oxide-coated zinc oxide particles, the decomposition rate of brilliant blue produced by the photocatalytic activity of zinc oxide particles is preferably 3% or less, more preferably 2% or less, and still more preferably 1% or less .
Further, a silicon oxide film of silicon oxide-coated zinc oxide particles, "when the abundance ratio of the presence ratio in ^{Q 3} environments of silicon in ^Q 3, ^{Q 4} environment was ^{Q 4, Q 3 + Q 4} ≧ 0.6 and Q It is preferable to satisfy ⁴ / (Q ³ + Q ⁴ ) ≧ 0.5.

The average dispersed particle diameter of the silicon oxide-coated zinc oxide particles in the silicon oxide-coated zinc oxide particle-containing water-based composition of the present embodiment is preferably 10 nm or more and 2 μm or less, and more preferably 20 nm or more and 800 nm or less The thickness is preferably 25 nm or more and 500 nm or less. If the average dispersed particle size of the silicon oxide-coated zinc oxide particles is 10 nm or more, the crystallinity of the silicon oxide-coated zinc oxide particles is high, and therefore sufficient ultraviolet light shielding properties can be exhibited. On the other hand, if the average dispersed particle size of the silicon oxide-coated zinc oxide particles is 2 μm or less, no glaring, squeezing and the like will occur, and the feel of use when formulated into cosmetics is improved and the dispersion stability is improved. An improved and stable composition is obtained.
In the present embodiment, the dispersed particle size means the particle size of a state in which a plurality of silicon oxide-coated zinc oxide particles are collected and dispersed.

  According to the water-based composition containing silicon oxide-coated zinc oxide particles of the present embodiment, the ultraviolet-screening property is obtained even when applied to water-based cosmetics by containing a nonionic surfactant and a water-soluble vinyl polymer. Excellent.

[Method for producing silicon oxide-coated zinc oxide particle-containing aqueous composition]
The method for producing a water-based composition containing silicon oxide-coated zinc oxide particles according to this embodiment uniformly comprises predetermined amounts of a nonionic surfactant, a water-soluble vinyl polymer, water, and silicon oxide-coated zinc oxide particles. The method is not particularly limited as long as it can be mixed with

The nonionic surfactant and the water-soluble vinyl polymer are suitably mixed with water and a pH adjuster such as sodium hydroxide before mixing with the silicon oxide-coated zinc oxide particles to obtain a hydrogen ion index (pH) It is preferable to adjust to 4.0 to 8.5, more preferably 4.5 to 8.0, and still more preferably 5.0 to 7.5.
The pH adjuster is not particularly limited as long as it can be used as a cosmetic. As a pH adjuster, sodium hydroxide etc. are mentioned, for example.

  The viscosity of the silicon oxide-coated zinc oxide particle-containing water-based composition of the present embodiment can be adjusted by the content, pH, etc. of the nonionic surfactant and the water-soluble vinyl polymer, so that the desired viscosity can be obtained. It may be adjusted and mixed.

[Method of producing silicon oxide-coated zinc oxide particles]
A method of producing silicon oxide-coated zinc oxide particles in the present embodiment will be described.
The method for producing silicon oxide-coated zinc oxide particles in this embodiment comprises: at least at least one selected from the group consisting of Mg, Ca and Ba, composite particles obtained by coating silicon oxide containing alkali metal on the surface of zinc oxide particles. A step of mixing one species in a solution containing water, and replacing the alkali metal contained in the silicon oxide with at least one species selected from the group consisting of Mg, Ca and Ba (hereinafter referred to as “ It is a manufacturing method which has a substitution process ".) And a calcination process.

Incidentally, zinc oxide particles coated with silicon oxide containing an alkali metal before the substitution step, or silicon oxide coated zinc oxide containing at least one selected from the group consisting of Mg, Ca and Ba after the substitution step The particles, at least one of alkoxysilanes and oligomers of alkoxysilanes having a size of 10 or less, a catalyst and water are added, and the mixture is reacted by stirring for 30 minutes or more and 24 hours or less. A process may be provided in which a silicon oxide film having a high degree of condensation is formed.
Next, the method for producing silicon oxide-coated zinc oxide particles will be described in detail.

As zinc oxide particles formed by coating silicon oxide containing an alkali metal, a silicate containing an alkali metal such as sodium silicate and a zinc oxide particle are reacted to oxidize the surface of the zinc oxide particle You may use what was made to coat silicon. Alternatively, commercially available silicon oxide-coated zinc oxide particles may be used.
As a method of coating silicon oxide on the surface of zinc oxide particles, for example, JP-A-03-183620, JP-A-11-256133, JP-A-11-302015, JP-A-2007-01611, etc. The methods described can be used.

Although the method of coat | covering the surface of a zinc oxide particle with a silicon oxide is selected as needed, the following method is mentioned, for example.
First, zinc oxide particles and water are mixed, and then the zinc oxide particles are ultrasonically dispersed in water to prepare a zinc oxide particle aqueous suspension.
Next, the zinc oxide particles aqueous suspension is heated, and while stirring the zinc oxide particles aqueous suspension, an aqueous solution of sodium silicate is added and aged for 10 minutes to 60 minutes.
Next, while stirring the zinc oxide particles aqueous suspension, an acid such as dilute sulfuric acid is added to adjust the pH to 5 to 9, and the mixture is aged for 30 minutes to 5 hours.
Next, the reaction solution is subjected to solid-liquid separation, and the obtained reaction product is washed with a solvent such as water, dried at about 100 ° C. to 200 ° C., and coated with an alkali metal-containing silicon oxide. Zinc oxide particles are obtained.

"Replacement process"
The substitution step needs to be performed after the step of coating the surface of the zinc oxide particles with silicon oxide containing an alkali metal. The reason is that magnesium silicate, calcium silicate as impurities when a silicate containing an alkali metal and at least one selected from the group consisting of Mg, Ca and Ba are simply mixed in a solution containing water And at least one precipitate of barium silicate is formed. Therefore, it is preferable to incorporate the substitution step in any step after the step of covering the surface of the zinc oxide particles with silicon oxide by neutralization reaction of the silicate or the like, to the step after the drying step. . According to such a method, the reaction process can be reduced, and the silicon oxide-coated zinc oxide particles in the present embodiment can be obtained at low cost.

In the substitution step, first, zinc oxide particles coated with an alkali metal-containing silicon oxide and at least one selected from the group consisting of Mg, Ca and Ba are added to a solution containing water and mixed. Do.
The solution containing water is not particularly limited, and may be selected as necessary. As a solution containing water, for example, water or a solution obtained by mixing water and a solvent compatible with water is used.
As a solvent compatible with water, for example, protic polar solvents such as methanol, ethanol, 2-propanol and the like and aprotic polar solvents such as acetone, tetrahydrofuran and the like are preferable. Among these, protic polar solvents such as methanol, ethanol and 2-propanol are more preferable.

The reaction temperature in this mixing process is not particularly limited, and is adjusted as necessary. It may be above the freezing point of the solvent in the liquid mixture containing zinc oxide particles coated with silicon oxide, at least one selected from the group consisting of Mg, Ca and Ba, and a solution containing water.
Although the reaction proceeds even when the mixed solution is left standing, in order to enhance the reaction efficiency, it is preferable to react while stirring the mixed solution.
The reaction time is not particularly limited and may be selected as necessary. The reaction time is preferably 1 hour or more.

  By this mixed treatment, the alkali metal in the silicon oxide-coated zinc oxide particles is substituted with at least one selected from the group consisting of Mg, Ca and Ba, and the silicon oxide-coated zinc oxide particles Elute into the mixture from. On the other hand, at least one ion selected from the group consisting of Mg, Ca and Ba substituted with an alkali metal is incorporated into silicon oxide-coated zinc oxide particles by substitution with the alkali metal, and as a result, Mg, Ca and Ba And silicon oxide-coated zinc oxide particles containing at least one selected from the group consisting of

  The content of at least one selected from the group consisting of Mg, Ca and Ba contained in the mixed solution is not particularly limited, and is selected as necessary. In order to ion-exchange alkali metal ions such as Na and K in zinc oxide particles coated with silicon oxide with at least one ion selected from the group consisting of Mg, Ca and Ba It is preferable that the content of at least one selected from the group consisting of Mg, Ca and Ba contained in the above is the sum of the molar equivalents of alkali metals in zinc oxide particles coated with silicon oxide.

As a raw material for providing at least 1 sort (s) selected from the group which consists of Mg, Ca, and Ba, if it is an inorganic salt containing these elements, it does not specifically limit. As a raw material for providing Mg, magnesium chloride, magnesium sulfate, magnesium nitrate etc. are mentioned, for example. As a raw material for providing Ca, calcium chloride, a calcium nitrate, etc. are mentioned, for example. As a raw material for providing Ba, barium chloride, barium nitrate etc. are used suitably, for example.
These raw materials may be used in the form of solid or in the form of an aqueous solution.

Next, the liquid mixture containing silicon oxide-coated zinc oxide particles produced in this substitution step is subjected to solid-liquid separation by atmospheric pressure filtration, vacuum filtration, pressure filtration, centrifugal separation or the like. The resulting solid is washed with a solvent such as water to obtain silicon oxide-coated zinc oxide particles.
In order to further reduce the content of the alkali metal in the obtained silicon oxide-coated zinc oxide particles, after the solid-liquid separation, the obtained silicon oxide-coated zinc oxide particles and Mg, Ca and Ba are again obtained. And at least one selected from the group consisting of Mg, Ca, and Ba selected from the group consisting of Mg, Ca, and Ba, mixed in a solution containing water, in the silicon oxide-coated zinc oxide particles. It is preferable to carry out the substitution step of It is more preferable to repeat this replacement step multiple times.

Since the silicon oxide-coated zinc oxide particles thus obtained contain water, it is preferable to dry to remove the water.
The drying temperature is not particularly limited, but in general, drying at a temperature of 100 ° C. or higher is preferable. Moreover, when drying at a temperature of 80 ° C. or less, drying under reduced pressure is preferable.

  Next, the dried product is subjected to heat treatment (baking) at 200 ° C. or more and less than 600 ° C., whereby the silicon oxide-coated zinc oxide particles in the present embodiment can be produced.

[Cosmetics]
The cosmetic of the present embodiment contains the silicon oxide-coated zinc oxide particle-containing aqueous composition of the present embodiment and a cosmetic base material.
The cosmetic of the present embodiment preferably contains water.

Here, the cosmetic base material means various materials forming the main body of the cosmetic, and examples thereof include an oily material, an aqueous material, a surfactant, and a powder material.
As an oil-based raw material, fats and oils, a higher fatty acid, a higher alcohol, ester oils etc. are mentioned, for example.
Examples of the aqueous material include purified water, alcohol, thickener and the like.
As a powder raw material, a colored pigment, a white pigment, a pearlescent agent, an extender pigment etc. are mentioned.

For example, the cosmetic composition of the present embodiment uses the silicon oxide-coated zinc oxide particle-containing aqueous composition of the present embodiment as a cosmetic base material such as emulsion, cream, foundation, lipstick, blusher and eye shadow by a known method It is obtained by blending.
In addition, the cosmetic composition of the present embodiment is prepared by blending the silicon oxide-coated zinc oxide particle-containing aqueous composition of the present embodiment into an oil phase or an aqueous phase to form an O / W or W / O type emulsion. It can also be obtained by blending with a base material.

  The content of the silicon oxide-coated zinc oxide particles in the cosmetic may be appropriately adjusted according to the desired characteristics, for example, the lower limit of the content of the silicon oxide-coated zinc oxide particles is 0.01 mass% or more It may be 0.1% by mass or more, or 1% by mass or more. The upper limit of the content of the silicon oxide-coated zinc oxide particles may be 50% by mass or less, 40% by mass or less, or 30% by mass or less.

  According to the cosmetic of the present embodiment, since the silicon oxide-coated zinc oxide particle-containing aqueous composition of the present embodiment is contained, the ultraviolet shielding properties are excellent.

[In-oil type cosmetics]
The oil-in-water cosmetic of the present embodiment comprises the silicon oxide-coated zinc oxide particle-containing aqueous composition of the present embodiment in an aqueous phase.

The oil-in-water cosmetic of the present embodiment is an oil-in-water emulsion in which the aqueous phase contains the silicon oxide-coated zinc oxide particle-containing aqueous composition of the present embodiment, and the oil phase contains an oil component.
The aqueous phase optionally contains additives such as dispersants, stabilizers, water-soluble binders (water-soluble polymers), thickeners, alcohols, etc. that are generally used in water-based cosmetics. Good.
In the oil phase, if necessary, additives generally used in cosmetics such as oil-soluble preservatives, ultraviolet light absorbers, oil-soluble drugs, oil-soluble pigments, oil-soluble proteins, vegetable oils, animal oils, solvents and the like May be included as appropriate.

The oil component is not particularly limited as long as it is used for cosmetics, and one that can dissolve a desired organic ultraviolet screening agent is appropriately selected.
As such an oil component, one containing at least one selected from the group consisting of a higher alcohol, a higher fatty acid, and a fatty acid ester formed by combining a higher alcohol and a higher fatty acid is preferable. The oil component containing these components improves firmness and moisturizing feeling, and also improves the sustainability of these effects. A liquid organic ultraviolet absorber such as ethylhexyl methoxycinnamate can also be used as an oil component.

  As the higher alcohol, for example, capryl alcohol, lauryl alcohol, stearyl alcohol, oleyl alcohol, myristyl alcohol, cetyl alcohol, cholesterol, phytosterol and the like are suitably used. These higher alcohols may be used alone or in combination of two or more.

  As the higher fatty acid, for example, a saturated or unsaturated fatty acid having 12 to 24 carbon atoms is preferably used. For example, myristic acid, palmitic acid, stearic acid, isostearic acid, linoleic acid, arachidonic acid and the like are suitably used. Be One of these higher fatty acids may be used alone, or two or more thereof may be used in combination.

Examples of fatty acid esters include cetyl myristate, octyldodecyl myristate, isopropyl myristate, myristyl myristate, 2-hexyldecyl myristate, octyl palmitate, isopropyl palmitate, butyl stearate, stearyl stearate, octyl stearate Isocetyl stearate, glycol distearate, cetyl 2-ethylhexanoate, 2-ethylhexyl stearate, stearyl stearate, cholesteryl isostearate, isocetyl isostearate, isononyl isononanoate, ethyl oleate, decyl oleate, oleyl oleate, Diisopropyl sebacate, dioctyl sebacate, hexyl decyl dimethyl octanoate, cetyl octanoate, neo dioctoate Emissions chill glycol, hexyl laurate, tetra octanoate pentaerythrityl like are suitably used. These fatty acid esters may be used alone or in combination of two or more.
In the present embodiment, from the viewpoint of suppressing the separation of the water phase and the oil phase, the ester value of the fatty acid ester is preferably lower. Specifically, as the fatty acid ester, it is preferable to use one having an ester value of 95 to 170. Examples of such fatty acid esters include octyldodecyl myristate (ester number 100 to 111), cetyl 2-ethylhexanoate (ester number 135 to 160), and the like.

The oil-in-water cosmetic of the present embodiment preferably contains a chelating agent. By containing the chelating agent, it is possible to further suppress the fluctuation of the hydrogen index over time of the oil-in-water cosmetic.
The chelating agent is not particularly limited as long as it is used for cosmetics. As the chelating agent, for example, ethylenediaminetetraacetic acid (EDTA), ethylene glycoldiaminetetraacetic acid, diethylenetriaminepentaacetic acid, citric acid, phytic acid, polyphosphoric acid, metaphosphoric acid and the like are used. Among these, ethylenediaminetetraacetic acid (EDTA) is preferable in terms of high versatility.

The content of the chelating agent in the oil-in-water cosmetic is appropriately adjusted in accordance with the desired performance, but is preferably, for example, 0.01% by mass or more and 1.0% by mass or less.
Here, if the content of the chelating agent is 0.01% by mass or more, desired properties can be obtained in the oil-in-water cosmetic. On the other hand, if the content of the chelating agent is 1.0% by mass or less, the oil-in-water cosmetic can be used safely. For example, the blending amount of ethylenediaminetetraacetic acid (EDTA) in cosmetics is regulated to 1.0% or less in the quasi-drug raw material standard.

The oil-in-water cosmetic of the present embodiment preferably contains an organic ultraviolet screening agent in the oil phase.
The organic ultraviolet screening agent is not particularly limited as long as it is used for cosmetics. Examples of organic UV screening agents include anthranilates, cinnamic acid derivatives, salicylic acid derivatives, camphor derivatives, benzophenone derivatives, β, β'-diphenyl acrylate derivatives, benzotriazole derivatives, benzalmalonate derivatives, benzo Examples include imidazole derivatives, imidazolines, bisbenzoazolyl derivatives, p-aminobenzoic acid (PABA) derivatives, methylene bis (hydroxyphenylbenzotriazole) derivatives and the like. As the organic ultraviolet screening agent, at least one selected from the above group is used.

The average dispersed particle size of the silicon oxide-coated zinc oxide particles in the oil-in-water cosmetic of the present embodiment is preferably 10 nm or more and 2 μm or less, more preferably 20 nm or more and 800 nm or less, and 25 nm or more And it is further more preferable that it is 500 nm or less.
When the average dispersed particle size of the silicon oxide-coated zinc oxide particles is 10 nm or more, the crystallinity of the silicon oxide-coated zinc oxide particles does not decrease, and therefore, sufficient ultraviolet shielding properties can be exhibited. On the other hand, if the average dispersed particle size of the silicon oxide-coated zinc oxide particles is 2 μm or less, no glaring, squeezing and the like will occur, the feel of use will be improved, the dispersion stability will be improved and the stable oil-in-water A cosmetic of type is obtained. In the present embodiment, the dispersed particle size means the particle size of a state in which a plurality of silicon oxide-coated zinc oxide particles are collected and dispersed.

The oil-in-water cosmetic according to the present embodiment may be added to the above-described components and the like by appropriately adding other components, etc., such as emulsion, cream, sunscreen, foundation, serum, makeup base, lipstick, etc. You may use it in a form.
Other components include zinc oxide particles, inorganic ultraviolet screening agents such as titanium oxide, organic ultraviolet screening agents, whitening agents, thickeners, etc., additives generally used in cosmetics, cosmetic base materials, etc. Can be mentioned.

  According to the oil-in-water cosmetic of the present embodiment, since the silicon oxide-coated zinc oxide particle-containing aqueous composition of the present embodiment is contained, a cosmetic excellent in ultraviolet shielding properties and feeling in use can be obtained.

[Method of Producing Oil-in-Water Cosmetics]
In the method for producing the oil-in-water cosmetic of the present embodiment, an oil-in-water type (O in which the aqueous composition containing silicon oxide-coated zinc oxide particles of the present embodiment is contained in the aqueous phase and the oil component is contained in the oil phase It is not particularly limited as long as it is a method capable of producing a cosmetic of / W).

  For example, water, a silicon oxide-coated zinc oxide particle-containing aqueous composition according to this embodiment, a pH adjuster, and an emulsifier are mixed in advance to form a mixture for the aqueous phase. And an oil component is added and mixed with the mixture for this water phase, and the oil-in-water type cosmetics of this embodiment can be produced by setting it as an oil-in-water type emulsion.

  When the silicon oxide-coated zinc oxide particle-containing aqueous composition contains an alkyl-modified carboxyvinyl polymer or an alkyl acrylate / methacrylic acid / polyoxyethylene copolymer, the alkyl portion plays a role of an emulsifier. Therefore, it is not necessary to add an emulsifier.

  The emulsifier is not particularly limited as long as it can be used as a cosmetic for producing an oil-in-water emulsion. For example, hydrophilic surfactants can be suitably used, and as hydrophilic surfactants, glycerin, glycerin fatty acid ester, polyglycerin fatty acid ester, polyoxyethylene glycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol Fatty acid esters, polyoxyethylene (hereinafter abbreviated as "POE") sorbitan fatty acid esters, POE sorbite fatty acid esters, POE glycerin fatty acid esters, POE fatty acid esters, POE alkyl ethers, POE alkyl phenyl ethers, POE castor oil, POE alkylamine, POE fatty acid amide etc. are mentioned.

  When the organic ultraviolet shielding agent is contained, the oil component and the organic ultraviolet shielding agent may be mixed in advance, and then mixed and emulsified in the mixture for the aqueous phase.

  Hereinafter, the present invention will be specifically described by way of examples and comparative examples, but the present invention is not limited by these examples.

Example 1
[Preparation of silicon oxide-coated zinc oxide particles]
Zinc oxide particles (average particle diameter 35 nm; manufactured by Sumitomo Osaka Cement Co., Ltd.) and water were mixed, and then ultrasonic dispersion was performed to prepare a zinc oxide particle aqueous suspension having a content of zinc oxide particles of 20% by mass. .
Then, this zinc oxide particle aqueous suspension is added to an aqueous sodium silicate solution containing 20% by mass of sodium silicate in terms of silicon oxide based on the mass of zinc oxide particles in the aqueous zinc oxide particle suspension. Stir to a suspension.
The suspension was then warmed to 60 ° C. and the pH was adjusted to 6.5-7 by slowly adding dilute hydrochloric acid while stirring the suspension. Thereafter, the mixture is allowed to stand for 2 hours, and an aqueous solution of calcium chloride (50% by mass of calcium chloride dihydrate) having the same mass as that of zinc oxide particles in the suspension is further added and stirred, and further allowed to stand for 2 hours Placed.
Then, this suspension was subjected to solid-liquid separation by a centrifuge, and the obtained solid was washed with water. Thereafter, this solid was dried at 150 ° C., and heat treatment (baking) was further performed at 500 ° C. for 15 hours to produce silicon oxide-coated zinc oxide particles.
Subsequently, the silicon oxide-coated zinc oxide particles and 2-propanol are mixed, and then the mixture is ultrasonically dispersed, and silicon oxide-coated zinc oxide particles having a content of 10% by mass of the silicon oxide-coated zinc oxide particles A propanol suspension was prepared.
The suspension was then warmed to 60 ° C. and aqueous ammonia and water were added while stirring the suspension to adjust the pH of the suspension to 10-11. In addition, the addition amount of water was made to be 120 mass% with respect to the tetraethoxysilane in the tetraethoxysilane 2-propanol solution added later.
Furthermore, a tetraethoxysilane 2-propanol solution is added to this suspension in an amount of 15% by mass based on the total mass of zinc oxide particles in terms of the amount of dropwise addition of tetraethoxysilane (converted from sodium silicate) The mixture was slowly dropped so as to be the total including the amount of silicon, and stirring was continued for 6 hours.
Then, the suspension was subjected to solid-liquid separation by a centrifuge, and the obtained solid was dried at 120 ° C.
Next, the dried product was heat-treated (baked) at 500 ° C. for 3 hours to obtain silicon oxide-coated zinc oxide particles.

[Preparation of silicon oxide-coated zinc oxide particle-containing aqueous composition]
90 parts by mass of pure water and 0.4 parts by mass of an alkyl-modified carboxyvinyl polymer (trade name: PEMULEN TR-1, manufactured by Lubrizol Advanced Materials) were mixed in a homodisper.
Then, an aqueous solution of sodium hydroxide is added to this mixed solution to adjust the hydrogen ion index (pH) to 6.0, and further, pure water is added to adjust it to 100 parts by mass, and 0.4% by mass of polymer gel I got
Next, 30 parts by mass of the obtained 0.4% by mass polymer gel, 5 parts by mass of glycerin, and 65 parts by mass of the obtained silicon oxide-coated zinc oxide particles are dispersed in a homodisper to obtain a silicon oxide-coated zinc oxide A composition containing 65% by mass of particles was obtained.

90 parts by mass of pure water and 1.2 parts by mass of an alkyl-modified carboxyvinyl polymer (trade name: PEMULEN TR-1, manufactured by Lubrizol Advanced Materials) were mixed in a homodisper.
Then, an aqueous solution of sodium hydroxide is added to this mixed solution to adjust the hydrogen ion index (pH) to 6.0, and further, pure water is added to adjust it to 100 parts by mass, and a 1.2% by mass polymer gel I got
Then, 77 parts by mass of a composition containing 65% by mass of the obtained silicon oxide-coated zinc oxide particles, and polyoxyethylene octyldodecyl ether (trade name: Emulgen 2025G, manufactured by Kao Corporation) which is a nonionic surfactant 14.4 parts by mass of an aqueous solution containing 23% by mass and 8.6 parts by mass of 1.2% by mass polymer gel are mixed, 50% by mass of silicon oxide-coated zinc oxide particles, and 3.3 for nonionic surfactant A silicon oxide-coated zinc oxide particle-containing aqueous composition of Example 1 containing a mass% was obtained.

[Preparation of water-based cosmetics]
98 parts by mass of pure water and 0.2 parts by mass of carboxyvinyl polymer (trade name: Carbopol Ultrez 10 polymer, manufactured by Lubrizol Advanced Materials) were manually mixed.
Then, an aqueous solution of sodium hydroxide is added to this mixed solution to adjust the hydrogen ion index (pH) to 7.5, and further, pure water is added to adjust it to 100 parts by mass, and 0.2% by mass of carbomer gel I got
90 parts by mass of the obtained 0.2% by mass carbomer gel and 10 parts by mass of the aqueous composition of Example 1 were mixed to obtain an aqueous cosmetic preparation of Example 1.

[Evaluation of agglomerated particle size]
The aqueous cosmetic preparation of Example 1 was sandwiched between two slide glasses and observed with an optical microscope. An optical microscope observation image is shown in FIG.
The maximum value of the agglomerated particle size measured by observation with an optical microscope was 30 μm.

[Evaluation of SPF]
A coating film was formed on a quartz substrate to a thickness of 12 μm using the water-based cosmetic of Example 1, and the spectral transmittance of the coating film was measured with an SPF analyzer UV-1000S (manufactured by Labsphere). The results are shown in FIG. The SPF value was 7.

[Stability evaluation of viscosity of water-based composition]
The viscosity after producing the aqueous composition of Example 1 (0 hour) was measured with a BII rotational viscometer (manufactured by Toki Sangyo Co., Ltd.) under conditions of 20 ° C. and 30 rotations. The composition was stored at 40 ° C., and the viscosity was measured every predetermined time. The results are shown in FIG.

[Production of oil-in-water cosmetic products]
79.1 parts by mass of water, 0.6 parts by mass of PEG-60 hydrogenated castor oil, and 0.3 parts by mass of alkyl-modified carboxyvinyl polymer (trade name: PEMULEN TR-1, manufactured by Lubrizol Advanced Materials) are mixed. A gel adjusted to pH 7.0 with 1.8 mol / L potassium hydroxide and 10.0 parts by mass of ethylhexyl methoxycinnamate were mixed with a homodisper to obtain an oil-in-water type water-based cosmetic.
An oil-in-water cosmetic comprising 90 parts by mass of the oil-in-water type aqueous cosmetic and 10 parts by mass of the zinc oxide particle-containing aqueous composition of Example 1 and containing the aqueous composition of Example 1 in the water phase I got
An optical microscope observation image when the obtained oil-in-water cosmetic is applied to a black artificial skin is shown in FIG. As a result of light microscope observation, the coated film was uniform.

Example 2
[Preparation of silicon oxide-coated zinc oxide particle-containing aqueous composition]
In Example 1, instead of using 14.4 parts by mass of aqueous solution containing 23% by mass of polyoxyethylene octyldodecyl ether, aqueous solution 7.2% by mass of pure water and 23% by mass of polyoxyethylene octyldodecyl ether Silicon oxide-coated zinc oxide particles of Example 2 containing 50% by mass of silicon oxide-coated zinc oxide particles and 1.7% by mass of non-ionic surfactant in the same manner as in Example 1 except that the mass part is used A containing aqueous composition was obtained.

[Preparation of water-based cosmetics]
In the same manner as in Example 1 except that the silicon oxide-coated zinc oxide particle-containing aqueous composition of Example 2 was used instead of using the silicon oxide-coated zinc oxide particle-containing aqueous composition of Example 1. I got a water based cosmetic.

The agglomerated particle size of the water-based cosmetic was evaluated in the same manner as in Example 1. An optical microscope is shown in FIG.
The maximum value of the agglomerated particle size measured by optical microscope observation was 40 μm.

  The spectral transmittance of the coating film formed using the aqueous cosmetic preparation of Example 2 was measured in the same manner as in Example 1. The results are shown in FIG. The SPF value was 5.

[Production of oil-in-water cosmetic products]
In the same manner as in Example 1 except that the silicon oxide-coated zinc oxide particle-containing aqueous composition of Example 2 was used instead of using the silicon oxide-coated zinc oxide particle-containing aqueous composition of Example 1. An oil-in-water cosmetic was obtained.
An optical microscope observation image when the obtained oil-in-water cosmetic is applied to a black artificial skin is shown in FIG. As a result of the optical microscope observation, the coated film was more nonuniform than the coated film of Example 1.

[Example 3]
In Example 1, instead of using 14.4 parts by mass of an aqueous solution containing 23% by mass of polyoxyethylene octyldodecyl ether, 1.4 parts by mass of an aqueous solution containing 13 parts by mass of pure water and 23% by mass of polyoxyethylene octyldodecyl ether In the same manner as in Example 1, except that 50% by mass of silicon oxide-coated zinc oxide particles and 0.3% by mass of non-ionic surfactant were used, the water system containing silicon oxide-coated zinc oxide particles of Example 3 was used. The composition was obtained.

[Preparation of water-based cosmetics]
The same procedure as in Example 1 was repeated except that the silicon oxide-coated zinc oxide particle-containing aqueous composition of Example 3 was used instead of the silicon oxide-coated zinc oxide particle-containing aqueous composition of Example 1. I got a water based cosmetic.

The agglomerated particle size of the water-based cosmetic was evaluated in the same manner as in Example 1. An optical microscope is shown in FIG.
The maximum value of the agglomerated particle size measured by optical microscope observation was 50 μm.

  The spectral transmittance of the coating film formed using the aqueous cosmetic preparation of Example 3 was measured in the same manner as in Example 1. The results are shown in FIG. The SPF value was 4.

[Production of oil-in-water cosmetic products]
The same procedure as in Example 1 was repeated except that the silicon oxide-coated zinc oxide particle-containing aqueous composition of Example 3 was used instead of the silicon oxide-coated zinc oxide particle-containing aqueous composition of Example 1. An oil-in-water cosmetic was obtained.
An optical microscope observation image when the obtained oil-in-water cosmetic is applied to a black artificial skin is shown in FIG. As a result of the optical microscope observation, the coated film was more nonuniform than the coated film of Example 2.

[Comparative example]
In the same manner as in Example 1, except that 14.4 parts by mass of pure water was used instead of 14.4 parts by mass of an aqueous solution containing 23% by mass of polyoxyethylene octyldodecyl ether in Example 1, a silicon oxide coated oxide was oxidized. A silicon oxide-coated zinc oxide particle-containing aqueous composition containing 50% by mass of zinc particles and 0.0% by mass of a nonionic surfactant was obtained.

[Preparation of water-based cosmetics]
A water-based makeup of a comparative example is carried out in the same manner as in Example 1, except that the silicon oxide-coated zinc oxide particle-containing water-based composition of the comparative example is used instead of the silicon oxide-coated zinc oxide particle-containing water-based composition of the first example. I got a fee.

The agglomerated particle size of the water-based cosmetic was evaluated in the same manner as in Example 1. An optical microscope is shown in FIG.
The maximum value of the agglomerated particle size measured by optical microscope observation was 80 μm.

  The spectral transmittance of the coating film formed using the aqueous cosmetic preparation of the comparative example was measured in the same manner as in Example 1. The results are shown in FIG. The SPF value was 3.

[Production of oil-in-water cosmetic products]
In the same manner as in Example 1 except that the silicon oxide-coated zinc oxide particle-containing aqueous composition of Comparative Example was used instead of using the silicon oxide-coated zinc oxide particle-containing water-based composition of Example 1, the oil-in-water of Comparative Example was used. I got a type of cosmetic.
An optical microscope observation image when the obtained oil-in-water cosmetic is applied to a black artificial skin is shown in FIG. As a result of the optical microscope observation, the coated film was more nonuniform than the coated film of Example 3.

  Comparing Examples 1 to 3 with the Comparative Example, the aqueous composition containing silicon oxide-coated zinc oxide particles and a nonionic surfactant when mixed with carboxyvinyl polymer gel widely used in aqueous cosmetics. It was confirmed that the aggregation of silicon oxide-coated zinc oxide particles is suppressed, and that the SPF value in the case of coating is improved.

  The water-based composition containing silicon oxide-coated zinc oxide particles according to the present invention is contained in water-based cosmetics because it contains silicon oxide-coated zinc oxide particles, a nonionic surfactant, and a water-soluble vinyl polymer. However, the desired ultraviolet shielding properties can be obtained. Therefore, UV shielding ability is required, application to water-based cosmetics and oil-in-water cosmetics that is excellent in feeling of use, as well as when used in fields other than cosmetics, selection of dispersants and resins The breadth can be broadened, and the degree of freedom in the formulation of paints and the like can be enhanced, and its industrial value is great.

Claims (7)

Water, nonionic surfactant, water-soluble vinyl polymer, silicon oxide coated zinc oxide particles,
An aqueous composition containing silicon oxide-coated zinc oxide particles, which has an aggregate particle size of 60 μm or less when it is incorporated into a gel containing a carboxyvinyl polymer.   Content of the said nonionic surfactant with respect to 100 mass parts of said silicon oxide coating zinc oxide particles is 0.1 mass part or more and 10.0 mass parts or less, The silicon oxide of Claim 1 characterized by the above-mentioned. Coated zinc oxide particle-containing aqueous composition.   Content of the said water-soluble vinyl polymer with respect to 100 mass parts of said silicon oxide coating zinc oxide particles is 0.02 mass part or more and 6.0 mass parts or less, The oxidation of Claim 1 or 2 characterized by the above-mentioned. Silicon-coated zinc oxide particle-containing aqueous composition.   The silicon oxide-coated zinc oxide particle-containing aqueous composition according to any one of claims 1 to 3, wherein the nonionic surfactant is an ether type.   The silicon oxide-coated zinc oxide particle-containing aqueous composition according to any one of claims 1 to 4, wherein the water-soluble vinyl polymer is an alkyl-modified carboxyvinyl polymer.   A cosmetic comprising the silicon oxide-coated zinc oxide particle-containing aqueous composition according to any one of claims 1 to 5 and a cosmetic base material.   An oil-in-water cosmetic comprising the aqueous composition containing silicon oxide-coated zinc oxide particles according to any one of claims 1 to 5 in an aqueous phase.